AU2013202057B2 - Acyltransferases and uses therof in fatty acid production - Google Patents

Abstract

Acyltransferases and uses therof in fatty acid production Abstract 5 The present invention relates to the recombinant manufacture of polyunsaturated fatty ac ids. Specifically, it relates to acyltransferase polypeptides, polynucleotides encoding said acyltransferases as well as vectors, host cells, non-human transgenic organisms containing said polynucletides. Moreover, the present invention contemplates methods for the manu facture of polyunsaturated fatty acids as well as oils obtained by such methods.

Description

Acyltransferases and uses therof in fatty acid production The present invention relates to the recombinant manufacture of polyunsaturated fatty ac ids. Specifically, it relates to acyltransferase polypeptides, polynucleotides encoding said 5 acyltransferase polypeptides as well to vectors, host cells, non-human transgenic organ isms containing said polynucletides. Moreover, the present invention contemplates methods for the manufacture of polyunsaturated fatty acids as well as oils obtained by such methods. Fatty acids and triacylglycerides have a various applications in the food industry, in animal 10 feed, supplement nutrition, and in the cosmetic and pharmacological and pharmaceutical field. The individual applications may either require free fatty acids or triacylglycerides. In both cases, however, polyunsaturated fatty acids either free or esterified are of pivotal in terest for many of the aforementioned applications. In particular, polyunsaturated omega-3 fatty acids and omega-6-fatty acids are important constituents in animal and human food. 15 These fatty acids are supposed to have beneficial effects on the overall health and, in par ticular, on the central nervous system, the cardivovascular system, the immune system, and the general metabolism. Within traditional food, the polyunsaturated omega-3-fatty acids are mainly found in fish and plant oils. However, in comparison with the needs of the indus try and the need for a beneficial diet, this source is rather limited. 20 The various polyunsaturated fatty acids (PUFA) and PUFA-containing triglycerides are also mainly obtained from microorganisms such as Mortierella and Schizochytrium or from oil producing plants such as soybean or oilseed rape, algae such as Crypthecodinium or Phaeodactylum and others, where they are usually obtained in the form of their triacylglyc 25 erides. The free PUFA are usually prepared from the triacylglycerides by hydrolysis. How ever, long chain polyunsaturated fatty acids (LCPUFA) having a C-18, C-20, C-22 or C-24 fatty acid body, such as docoahexaenoic acid (DHA), eicosapentaenoic acid (EPA), arachi donic acid (ARA), dihomo-gamma-linolenic acid or docosapentaenoic acid (DPA) can not be efficiently isolated from natural oil crop plants such as oilseed rape, soybean, sunflower 30 or safflower. Conventional natural sources of these fatty acids are, thus, merely fish, such as herring, salmon, sardine, redfish, eel, carp, trout, halibut, mackerel, zander or tuna, or from algae. Especially suitable microorganisms for the production of PUFA in industrial scale are micro 35 algae such as Phaeodactylum tricornutum, Porphoridium species, Thraustochytrium spe cies, Nannochloropsis species, Schizochytrium species or Crypthecodinium species, cili ates such as Stylonychia or Colpidium, fungi such as Mortierella, Entomophthora or Mucor and/or mosses such as Physcomitrella, Ceratodon and Marchantia (Vazhappilly 1998, Botanica Marina 41: 553-558; Totani 1987, Lipids 22: 1060-1062; Akimoto 1998, Appl. Bio 4195554_1 (GHMattes) P92082.AU.1 chemistry and Biotechnology 73: 269-278). Strain selection has resulted in the development of a number of mutant strains of the microorganisms in question which produce a series of desirable compounds including PUFA. However, the mutation and selection of strains with an improved production of a particular molecule such as the polyunsaturated fatty acids is a 5 time-consuming and difficult process. This is why recombinant methods as described above are preferred whenever possible. However, only limited amounts of the desired PUFA or LCPUFA and, in particular, DHA or EPA, can be produced with the aid of the above men tioned microorganisms, and, depending on the microorganism used, these are generally obtained as fatty acid mixtures of, for example, EPA, DPA and DHA. 10 Many attempts in the past have been made to make available genes which are involved in the synthesis of fatty acids or triglycerides for the production of oils in various organisms. Various desaturases have been described in the art; see, e.g., documents WO 91/13972, WO 93/11245, WO 94/11516, EP-A-0 550 162, WO 94/18337, WO 97/30582, WO 15 97/21340, WO 95/18222, EP-A-0 794 250, Stukey 1990, J. Biol. Chem., 265: 20144-20149, Wada 1990, Nature 347: 200-203, Huang 1999, Lipids 34: 649-659, WO 93/06712, US 5,614,393, WO 96/21022, WO 00/21557, WO 99/27111, WO 98/46763, WO 98/46764, WO 98/46765, WO 99/64616 or WO 98/46776. These enzymes can be used for the production of unsaturated fatty acids. Thus, due to modern molecular biology, it has become possible 20 to increase at least to some extent the content of the desired polyunsaturated fatty acids and, in particular, the PUFA or LCPUFA in a given organism. Elongases for the production of fatty acids are disclosed in the document W02009/016202. The biosynthesis of LCPUFA and the incorporation of LCPUFA into membrane lipids or tri 25 acylglycerides proceeds via various metabolic pathways (Abbadi 2001, European Journal of Lipid Science & Technology 103:106-113). In bacteria such as Vibrio, and microalgae, such as Schizochytrium, malonyl-CoA is converted into LCPUFA via an LCPUFA-producing polyketide synthase (Metz 2001, Science 293: 290-293; WO 00/42195; WO 98/27203; WO 98/55625). In microalgae, such as Phaeodactylum, and mosses, such as Physcomitrella, 30 unsaturated fatty acids such as linoleic acid or linolenic acid are converted in a plurality of desaturation and elongation steps to give LCPUFA (Zank 2000, Biochemical Society Transactions 28: 654-658). Desaturation takes place either on acyl groups bound to Coen zyme A (acyl-CoA) or on acyl groups of membrane lipids, whereas elongation is biochemi caly restricted to acyl chains bound to CoA. In mammals, the biosynthesis of DHA com 35 prises a chain shortening via beta-oxidation, in addition to desaturation and elongation steps. In microorganisms and lower plants, LCPUFA are present either exclusively in the form of membrane lipids, as is the case in Physcomitrella and Phaeodactylum, or in mem brane lipids and triacylglycerides, as is the case in Schizochytrium and Mortierella. Incorpo ration of LCPUFA into lipids and oils, as well as the transfer of the fatty acid moiety (acyl 4195554_1 (GHMattes) P92082.AU.1 group) between lipids and other molecular species such as acyl-CoA, is catalyzed by vari ous acyltransferases and transacylases. These enzymes are, known to carry out the incor poration or interexchange of saturated and unsaturated fatty acids (Slabas 2001, J. Plant Physiology 158: 505-513, Frentzen 1998, Fett/Lipid 100: 161-166, Cases 1998, Proc. Nat. 5 Acad. Sci. USA 95: 13018-13023). One group of acyltransferases having three distinct en zymatic activities are enzymes of the "Kennedy pathway", which are located on the cyto plasmic side of the membrane system of the endoplasmic reticulum (ER). The ER-bound acyltransferases in the microsomal fraction use acyl-CoA as the activated form of fatty ac ids. Glycerol-3-phosphate acyltransferase (GPAT) catalyzes the incorporation of acyl 10 groups at the sn-1 position of glycerol-3-phosphate. 1-Acylglycerol-3-phosphate acyltrans ferase, also known as lysophosphatidic acid acyltransferase (LPAAT), catalyze the incorpo ration of acyl groups at the sn-2 position of lysophosphatidic acid (LPA). After dephosphory lation of phosphatidic acid by phosphatidic acid phosphatase (PAP), diacylglycerol acyl transferase (DGAT) catalyzes the incorporation of acyl groups at the sn-3 position of diacyl 15 glycerols. Further enzymes directly involved in TAG biosynthesis - apart from the said Ken nedy pathway enzymes - are the phospholipid diacylglycerol acyltransferase (PDAT), an enzyme that transfers acyl groups from the sn-2 position of membrane lipids to the sn-3 position of diacylglycerols, and diacylglyceroldiacylglycerol transacylase (DDAT), an en zyme that transfers acylgroups from the sn-2 position of one diacylglycerol-molecule to the 20 sn-3 position of another diacylglycerol-molecule. Lysophospholipid acyltransferase (LPLAT) represents a class of acyltransferases that are capable of incorporating activated acyl groups from acyl-CoA to membrane lipids, and possibly catalyze also the reverse reaction. More specifically, LPLATs can have activity as lysophosphophatidylethanolamine acyltrans ferase (LPEAT) and lysophosphatidylcholine acyltransferase (LPCAT). Further enzymes, 25 such as lecithin cholesterol acyltransferase (LCAT) can be involved in the transfer of acyl groups from membrane lipids into triacylglycerides, as well. The documents WO 98/54302 and WO 98/54303 disclose a human LPAAT and its potential use for the therapy of diseases, as a diagnostic, and a method for identifying modulators of 30 the human LPAAT. Moreover, a variety of acyltransferases with a wide range of enzymatic functions have been described in the documents WO 98/55632, WO 98/55631, WO 94/13814, WO 96/24674, WO 95/27791, WO 00/18889, WO 00/18889, WO 93/10241, Ak ermoun 2000, Biochemical Society Transactions 28: 713-715, Tumaney 1999, Biochimica et Biophysica Acta 1439: 47-56, Fraser 2000, Biochemical Society Transactions 28: 715 35 7718, Stymne 1984, Biochem. J. 223: 305-314, Yamashita 2001, Journal of Biological Chemistry 276: 26745-26752, and WO 00/18889. Higher plants comprise PUFA, such as linoleic acid and linolenic acid. However, the LCPUFA ARA, EPA and DHA are not present in the seed oils of higher plants or only in 4195554_1 (GHMattes) P92082.AU.1 traces (Ucciani: Nouveau Dictionnaire des Huiles V6g6tales. Technique & Documentation Lavoisier, 1995. ISBN: 2-7430-0009-0). It is nevertheless highly desirable to produce LCPUFA in higher plants, preferably in oil seeds such as oilseed rape, linseed, sunflower and soybean, since large amounts of high-quality LCPUFA for the various aforementioned 5 applications may be obtained thereby at low costs. However, one drawback of using transgenic plants expressing various of the aforemen tioned desaturases and elongases involved in the synthesis of PUFA and LCPUFA is that the latter are not efficiently incorporated into triacylglycerides, but rather into membranes. 0 Furthermore, efficient processing of a given acyl molecule-substrate, e.g. linoleic acid, by a plurality of desaturation and elongation steps towards the desired LCPUFA, e.g. ARA, EPA and/or DHA, is hindered by the requirement to transfer the acyl molecule and its derivatives generated by the elongation and desaturation reactions back and forth between membrane lipids and acyl-CoA. For this reason, intermediates towards desired LCPUFA are incorpo 5 rated into oil before the synthesis of the desired LCPUFA is complete. These two problems are undesired for the following reasons: First, the main lipid fraction in oil seeds are triacyl glycerides. This is why, for economical reasons, it is necessary to concentrate LCPUFA in triacylglycerides. Second, LCPUFA which are incorporated into membranes can modify the physical characteristics of the membranes and thus have harmful effects on the integrity .0 and transport characteristics of the membranes and on the stress tolerance of plants. Third, for efficient LCPUFA synthesis, it is desirable to increase the flux of intermediate-LCPUFA between the two sites of biosynthesis -that are membrane lipids and acyl-CoA - and/or de crease the flux of intermediate-PUFA/-LCPUFA into oil. Transgenic plants which comprise and express genes coding for enzymes of LCPUFA biosynthesis and produce LCPUFA .5 have been described, e.g., in DE 102 19 203 or W02004/087902. However, these plants produce LCPUFA in amounts which require further optimization for processing the oils pre sent in said plants. Moreover, it was proposed that delta 6 desaturated fatty acids may be shifted into the acyl-CoA pool for increasing efficiency of fatty acid elongation in plants (Singh 2005, Curr. Opn. Plant B/ol., 8: 197-203). Another publication demonstrated in Ara 30 bidopsis, that the additional expression of RcDGAT2 from Ricinus communis increase the storage of hydroxyfatty acids produced by a Ricinus communis fatty acid hydroxylase 12 (FAH 12) from 17% to 30% in the seed oil. Accordingly, means for increasing the content of PUFA or LCPUFA, such as EPA and DHA, 35 in triglycerides in, e.g., plant seed oils, are still highly desirable. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, 7065178_1 (GHMatters) P92082.AU.1 i.e. to specify the presence of the stated features but not to preclude the presence or addi tion of further features in various embodiments of the invention. It is to be understood that, if any prior art publication is referred to herein, such reference 5 does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country. Thus, the present invention relates to a polynucleotide comprising a nucleic acid sequence elected from the group consisting of: 0 a) a nucleic acid sequence having a nucleotide sequence as shown in any one of SEQ ID 7065178_1 (GHMatters) P92082.AU.1 NOs: 52, 1,4,7,10,13,16,19,22,25,28,31,34, 37, 40, 43, 46, 49, and 55; b) a nucleic acid sequence encoding a polypeptide having an amino acid sequence as shown in any one of SEQ ID NOs: 53, 2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, 38, 41, 44, 47, 50, and 56; 5 c) a nucleic acid sequence being at least 40% identical to the nucleic acid sequence of a) or b), wherein said nucleic acid sequence encodes a polypeptide having acyltransferase activity; d) a nucleic acid sequence encoding a polypeptide having acyltransferase activity and having an amino acid sequence which is at least 45% identical to the amino acid se 10 quence ofb); and e) a nucleic acid sequence which is capable of hybridizing under one of the following sets of conditions to any one of a) to d), wherein said nucleic acid sequence encodes a polypeptide having acyltransferase activity: f) hybridization in 50 mM Tris, pH 7.6, 6xSSC, 5xDenhardt's, 1.0% sodium dodecyl sulfat 15 (SDS) 100pg denaturated calf thymus DNA at 340C overnight and wash twice with 2xSSC, 0.5%SDS at room temperature for 15 min each, repeat twice with 0.2xSSC, 0,5% SDS at room temperature for 15 min each and then repeat twice with 0.2 SSC, 0.5% SDS at 500C for 15 min; g) hybridization in 6xSSPE (Sodium chloride Sodium Phosphate-EDTA), 5xDenhardt's 20 solution, 0.5% SDS 100pg denaturated calf thymus DNA at 340C overnight and wash twice with 2xSSC, 0.5%SDS at room temperature for 15 min each, repeat twice with 0.2xSSC, 0,5% SDS at room temperature for 15 min each and then repeat twice with 0.2 SSC, 0.5% SDS at 500C for 15 min; h) hybridization in 20-30% formamide, 5xSSPE, 5xDenhardt's solution, 1% SDS 100pg 25 denaturated salmon sperm DNA at 340C overnight and wash twice with 2xSSPE, 0.2%SDS at 420C for 15 min each, repeat twice with 2xSSPE, 0.2%SDS at 550C for 30 min each and repeat twice with 0.2 SSC, 0.5% SDS at 500C for 15 min; i) hybridization in 7% SDS, 0.5 M NaPO4, 1 mM EDTA at 500C overnight and wash in 2 X SSC, 0.1% SDS at 500C or 650C; 30 j) hybridization in 7% SDS, 0.5 M NaPO4, 1 mM EDTA at 500C overnight and wash in 1 X SSC, 0.1% SDS at 500C or 650C; or k) hybridization in 7% SDS, 0.5 M NaPO4, 1 mM EDTA at 500C overnight and wash in 0,1 X SSC, 0.1% SDS at 500C or 650C 35 The term "polynucleotide" as used in accordance with the present invention relates to a polynucleotide comprising a nucleic acid sequence which encodes a polypeptide having acyltransferase activity. Preferably, the polypeptide encoded by the polynucleotide of the present invention having acyltransferas activity upon expression in a plant shall be capable of increasing the amount of PUFA and, in particular, LCPUFA esterified to triglycerides in, 4195554_1 (GHMattes) P92082.AU.1 e.g., seed oils or the entire plant or parts thereof. Such an increase is, preferably, statisti cally significant when compared to a LCPUFA producing transgenic control plant which ex presses the minimal set of desaturases and elongases requiered for LCPUFA synthesis but does not express the polynucleotide of the present invention. Such a transgenic plant may, 5 preferably, express desaturases and elongases comprised by the vector LJB765 listed in table 11 of example 5 in W02009/016202 or a similar set of desaturases and elongases required for DHA synthesis. Whether an increase is significant can be determined by statis tical tests well known in the art including, e.g., Student's t-test. More preferably, the in crease is an increase of the amount of triglycerides containing LCPUFA of at least 5%, at 10 least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, atleast 45% or at least 50% compared to the said control. Preferably, the LCPUFA referred to before is a polyunsaturated fatty acid having a C-20, C-22 or C24 fatty acid body, more preferably, EPA or DHA, most preferably, DHA. Suitable assays for measuring the activities mentioned before are described in the accompanying Examples. 15 The term "acyltransferase activity" or "acyltransferase" as used herein encompasses all enymatic activities and enzymes which are capable of transferring or are involved in the transfer of PUFA and, in particular; LCPUFA from the acly-CoA pool or the membrane phospholipis to the triglycerides, from the acyl-CoA pool to membrane lipids and from 20 membrane lipids to the acyl-CoA pool by a transesterification process. It will be understood that this acyltransferase activity will result in an increase of the LCPUFA esterified to triglycerides in, e.g., seed oils. In particular, it is envisaged that these acyltransferases are capable of producing triglycerides having esterified EPA or even DHA, or that these acyl transferases are capable of enhancing synthesis of desired PUFA by increasing the flux for 25 specific intermediates of the desired PUFA between the acyl-CoA pool (the site of elonga tion) and membrane lipids (the predominant site of desaturation). Specifically, acyltrans ferase activity as used herein relates to lysophospholipid acyltransferase (LPLAT) activity, preferably, lysophosphatidylcholine acyltransferase (LPCAT) or Lysophosphophatidyletha nolamine acyltransferase (LPEAT) activity, lysophosphosphatidic acid acyltransferase 30 (LPAAT) activity, glycerol-3-phosphate acyltransferase (GPAT) activity or diacylglycerol acyltransferase (DGAT), and, more preferably, to LPLAT, LPAAT, DGAT or GPAT activity. More preferably, polynucleotides having a nucleic acid sequence as shown in SEQ ID NOs: 1, 4, and 7, encoding polypeptides having amino acid sequences as shown in SEQ ID NOs: 35 2, 5, and 8 or variants thereof, preferably, exhibit LPLAT activity. Polynucleotides having a nucleic acid sequence as shown in SEQ ID NOs: 10, and 13, encoding polypeptides having amino acid sequences as shown in SEQ ID NOs: 11, and 14 or variants thereof, preferably, exhibit LPAAT activity. Polynucleotides having a nucleic acid sequence as shown in SEQ ID NOs: 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49, 52, and 55, encoding polypeptides hav 4195554_1 (GHMattes) P92082.AU.1 ing amino acid sequences as shown in SEQ ID NOs: 17, 20, 23, 26, 29, 32, 35, 38, 41, 44, 47, 50, 53 , and 56 or variants thereof, preferably, exhibit DGAT activity. A polynucleotide having a nucleic acid sequence as shown in SEQ ID NO: 55, encoding a polypeptide having amino acid sequences as shown in SEQ ID NO: 56 or variants thereof, preferably, exhibit 5 GPAT activity. A polynucleotide encoding a polypeptide having a acyltransferase activity as specified above has been obtained in accordance with the present invention, preferably, from Nan noch/oropsis oculata and/or Thraustochytrium aureum. However, orthologs, paralogs or 10 other homologs may be identified from other species. Thus, the term "polynucleotide" as used in accordance with the present invention further encompasses variants of the aforementioned specific polynucleotides representing orthologs, paralogs or other homologs of the polynucleotide of the present invention. More 15 over, variants of the polynucleotide of the present invention also include artificially gener ated muteins. Said muteins include, e.g., enzymes which are generated by mutagenesis techniques and which exhibit improved or altered substrate specificity, or codon optimized polynucleotides. The polynucleotide variants, preferably, comprise a nucleic acid sequence characterized in that the sequence can be derived from the aforementioned specific nucleic 20 acid sequences shown in any one of SEQ ID NOs: 52, 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49, and 55 or by a polynucleotide encoding a polypeptide having an amino acid sequence as shown in any one of SEQ ID NOs: 53, 2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, 38, 41, 44, 47, 50, and 56 by at least one nucleotide substitution, addition and/or deletion, whereby the variant nucleic acid sequence shall still encode a polypeptide 25 having a acyltransferase activity as specified above. Variants also encompass polynucleo tides comprising a nucleic acid sequence which is capable of hybridizing to the aforemen tioned specific nucleic acid sequences, preferably, under stringent hybridization conditions. These stringent conditions are known to the skilled artisan and can be found in Current Pro tocols in Molecular Biology, John Wiley & Sons, N. Y. (1989), 6.3.1-6.3.6. A preferred ex 30 ample for stringent hybridization conditions are hybridization conditions in 6 x sodium chlo ride/sodium citrate (= SSC) at approximately 450C, followed by one or more wash steps in 0.2 x SSC, 0.1% SDS at 50 to 650C. The skilled artisan knows that these hybridization con ditions differ depending on the type of nucleic acid and, for example when organic solvents are present, with regard to the temperature and concentration of the buffer. For example, 35 under "standard hybridization conditions" the temperature differs depending on the type of nucleic acid between 420C and 580C in aqueous buffer with a concentration of 0.1 to 6 x SSC (pH 7.2). If organic solvent is present in the abovementioned buffer, for example 50% formamide, the temperature under standard conditions is approximately 420C. The hybridi zation conditions for DNA: DNA hybrids are, preferably, 0.1 x SSC and 200C to 450C, pref 4195554_1 (GHMattes) P92082.AU.1 erably between 300C and 450C and more preferably between 450C and 650C. The hybridi zation conditions for DNA:RNA hybrids are, more preferably, 0.1 x SSC and 300C to 550C, most preferably between 450C and 650C. The abovementioned hybridization temperatures are determined for example for a nucleic acid with approximately 100 bp (= base pairs) in 5 length and a G + C content of 50% in the absence of formamide. The skilled artisan knows how to determine the hybridization conditions required by referring to textbooks such as the textbook mentioned above, or the following textbooks: Sambrook et al., "Molecular Cloning", Cold Spring Harbor Laboratory, 1989; Hames and Higgins (Ed.) 1985, "Nucleic Ac ids Hybridization: A Practical Approach", IRL Press at Oxford University Press, Oxford; 10 Brown (Ed.) 1991, "Essential Molecular Biology: A Practical Approach", IRL Press at Oxford University Press, Oxford. In detail variants of polynucleotides still encode a polypeptide having a acyltransferase ac tivity as specified above comprising a nucleic acid sequence which is capable of hybridizing 15 preferably under conditions equivalent to hybridization in 50 mM Tris, pH 7.6, 6xSSC, 5xDenhardt's, 1.0% sodium dodecyl sulfat (SDS) 100pg denaturated calf thymus DNA at 340C overnight, followed by washing twice with 2xSSC, 0.5%SDS at room temperature for 15 min each, then wash twice with 0.2xSSC, 0,5% SDS at room temperature for 15 min each and then wash twice with 0.2 SSC, 0.5% SDS at 500C for 15 min each to a nucleic 20 acid described by any one of SEQ ID NOs: 52, 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49, and 55 or the complement thereof. More preferably, said variants of polynucleotides comprising a nucleic acid sequence which is capable of hybridizing under conditions equivalent to hybridization in 6xSSPE (Sodium 25 chloride Sodium Phosphate-EDTA), 5xDenhardt's solution, 0.5% sodium dodecyl sulfat (SDS) 100pg denaturated calf thymus DNA at 340C overnight, followed by washing twice with 2xSSC, 0.5%SDS at room temperature for 15 min each, then wash twice with 0.2xSSC, 0,5% SDS at room temperature for 15 min each and then wash twice with 0.2 SSC, 0.5% SDS at 500C for 15 min each to a nucleic acid described by any one of SEQ ID 30 NOs: 52, 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49, and 55 or the com plement thereof. Most preferably, said variants of polynucleotides comprising a nucleic acid sequence which is capable of hybridizing under conditions equivalent to hybridization in 20-30% formamide, 35 5xSSPE (Sodium chloride Sodium Phosphate-EDTA), 5xDenhardt's solution, 1% sodium dodecyl sulfat (SDS) 100pg denaturated salmon sperm DNA at 340C overnight, followed by washing twice with 2xSSPE, 0.2%SDS at 420C for 15 min each, then wash twice with 2xSSPE, 0.2%SDS at 550C for 30 min each and then wash twice with 0.2 SSC, 0.5% SDS at 500C for 15 min each to a nucleic acid described by any one of SEQ ID NOs: 52, 1, 4, 7, 4195554_1 (GHMattes) P92082.AU.1 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49, and 55 or the complement thereof. In another preferred embodiment aforementioned variants of polynucleotides still encode a polypeptide having a acyltransferase activity as specified above comprising a nucleic acid 5 sequence which is capable of hybridizing under conditions equivalent to hybridization in 7% sodium dodecyl sulfate (SDS), 0.5 M NaPO4, 1 mM EDTA at 500C overnight with washing in 2 X SSC, 0.1% SDS at 500C or 650C, preferably 650C to a nucleic acid described by any one of SEQ ID NOs: 52, 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49, and 55 or the complement thereof. In still another preferred embodiment, said variants of 10 polynucleotides comprising a nucleic acid sequence which is capable of hybridizing under conditions equivalent to hybridization in 7% sodium dodecyl sulfate (SDS), 0.5 M NaPO4, 1 mM EDTA at 500C overnight with washing in 1 X SSC, 0.1% SDS at 500C or 650C, prefera bly 650C to a nucleotide sequence described by any one of SEQ ID NOs: 52, 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49, and 55 or or the complement thereof, most 15 preferably, said variants of polynucleotides comprising a nucleic acid sequence which is capable of hybridizing under conditions equivalent to hybridization in 7% sodium dodecyl sulfate (SDS), 0.5 M NaPO4, 1 mM EDTA at 500C overnight with washing in 0,1 X SSC, 0.1% SDS at 500C or 650C, preferably 650C to a nucleic acid sequence described by any one of SEQ ID NOs: 52, 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49, and 20 55 or the complement thereof. The term "hybridization" as used herein includes "any process by which a strand of nucleic acid molecule joins with a complementary strand through base pairing." (J. Coombs (1994) Dictionary of Biotechnology, Stockton Press, New York). Hybridization and the strength of 25 hybridization (i.e., the strength of the association between the nucleic acid molecules) is impacted by such factors as the degree of complementarity between the nucleic acid mole cules, stringency of the conditions involved, the Tm of the formed hybrid, and the G:C ratio within the nucleic acid molecules. As used herein, the term "Tm" is used in reference to the "melting temperature." The melting temperature is the temperature at which a population of 30 double-stranded nucleic acid molecules becomes half dissociated into single strands. The equation for calculating the Tm of nucleic acid molecules is well known in the art. As indi cated by standard references, a simple estimate of the Tm value may be calculated by the equation: Tm=81.5+0.41(% G+C), when a nucleic acid molecule is in aqueous solution at 1 M NaCl [see e.g., Anderson and Young, Quantitative Filter Hybridization, in Nucleic Acid 35 Hybridization (1985)]. Other references include more sophisticated computations, which take structural as well as sequence characteristics into account for the calculation of Tm. Stringent conditions, are known to those skilled in the art and can be found in Current Pro tocols in Molecular Biology, John Wiley & Sons, N.Y. (1989), 6.3.1-6.3.6. 4195554_1 (GHMattes) P92082.AU.1 A "complement" of a nucleic acid sequence as used herein refers to a nucleotide sequence whose nucleic acid molecules show total complementarity to the nucleic acid molecules of the nucleic acid sequence. 5 The term "Complementary" or "complementarity" refers to two nucleotide sequences which comprise antiparallel nucleotide sequences capable of pairing with one another (by the base-pairing rules) upon formation of hydrogen bonds between the complementary base residues in the antiparallel nucleotide sequences. For example, the sequence 5'-AGT-3' is complementary to the sequence 5'-ACT-3'. Complementarity can be "partial" or "total." "Par 10 tial" complementarity is where one or more nucleic acid bases are not matched according to the base pairing rules. "Total" or "complete" complementarity between nucleic acid mole cules is where each and every nucleic acid base is matched with another base under the base pairing rules. The degree of complementarity between nucleic acid molecule strands has significant effects on the efficiency and strength of hybridization between nucleic acid 15 molecule strands. Alternatively, polynucleotide variants are obtainable by PCR-based techniques such as mixed oligonucleotide primer- based amplification of DNA, i.e. using degenerated primers against conserved domains of the polypeptides of the present invention. Conserved do 20 mains of the polypeptide of the present invention may be identified by a sequence compari son of the nucleic acid sequences of the polynucleotides or the amino acid sequences of the polypeptides of the present invention. Oligonucleotides suitable as PCR primers as well as suitable PCR conditions are described in the accompanying Examples. As a template, DNA or cDNA from bacteria, fungi, plants or animals may be used. 25 Further, variants include polynucleotides comprising nucleic acid sequences which are at least up to 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at 30 least 99% identical to the nucleic acid sequences shown in any one of SEQ ID NOs: 52, 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49, and 55, preferably, encoding polypeptides retaining a acyltransferase activity as specified above. Moreover, also encompassed are polynucleotides (derivatives) which comprise nucleic acid 35 sequences encoding a polypeptide having an amino acid sequences which are at least up to 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98% or at least 99% identical to the amino acid sequences shown in any one of SEQ ID NOs: 53, 2, 5, 8, 11, 14, 17, 20, 23, 26, 4195554_1 (GHMattes) P92082.AU.1 29, 32, 35, 38, 41, 44, 47, 50, and 56, wherein the polypeptide, preferably, retains acyl transferase activity as specified above. The percent identity values are, preferably, calcu lated over the entire amino acid or nucleic acid sequence region. A series of programs based on a variety of algorithms is available to the skilled artisan for comparing different 5 sequences. In a preferred embodiment, the percent identity between two amino acid se quences is determined using the Needleman and Wunsch algorithm (Needleman 1970, J. Mol. Biol. (48):444-453) which has been incorporated into the needle program in the EM BOSS software package (EMBOSS: The European Molecular Biology Open Software Suite, Rice,P., Longden,l., and Bleasby,A, Trends in Genetics 16(6), 276-277, 2000), using either 10 a BLOSUM 45 or PAM250 scoring matrix for distantly related proteins, or either a BLOSUM 62 or PAM160 scoring matrix for closer related proteins, and a gap opening penalty of 16, 14, 12, 10, 8, 6, or 4 and a gap entension pentalty of 0.5, 1, 2, 3, 4, 5, or 6. Guides for local installation of the EMBOSS package as well as links to WEB-Services can be found at http://emboss.sourceforge.net. A preferred, non-limiting example of parameters to be used 15 for aligning two amino acid sequences using the needle program are the default parame ters, including the EBLOSUM62 scoring matrix, a gap opening penalty of 10 and a gap ex tension penalty of 0.5. In yet another preferred embodiment, the percent identity between two nucleotide sequences is determined using the needle program in the EMBOSS soft ware package (EMBOSS: The European Molecular Biology Open Software Suite, Rice,P., 20 Longden,l., and Bleasby,A, Trends in Genetics 16(6), 276-277, 2000), using the EDNA FULL scoring matrix and a gap opening penalty of 16, 14, 12, 10, 8, 6, or 4 and a gap ex tension penalty of 0.5,1, 2, 3, 4, 5, or 6. A preferred, non-limiting example of parameters to be used in conjunction for aligning two amino acid sequences using the needle program are the default parameters, including the EDNAFULL scoring matrix, a gap opening penalty of 25 10 and a gap extension penalty of 0.5. The nucleic acid and protein sequences of the pre sent invention can further be used as a "query sequence" to perform a search against public databases to, for example, identify other family members or related sequences. Such searches can be performed using the BLAST series of programs (version 2.2) of Altschul et al. (Altschul 1990, J. Mol. Biol. 215:403-10). BLAST using acyltransferase nucleic acid se 30 quences of the invention as query sequence can be performed with the BLASTn, BLASTx or the tBLASTx program using default parameters to obtain either nucleotide sequences (BLASTn, tBLASTx) or amino acid sequences (BLASTx) homologous to acyltransferase sequences of the invention. BLAST using acyltransferase protein sequences of the inven tion as query sequence can be performed with the BLASTp or the tBLASTn program using 35 default parameters to obtain either amino acid sequences (BLASTp) or nucleic acid se quences (tBLASTn) homologous to acyltransferase sequences of the invention. To obtain gapped alignments for comparison purposes, Gapped BLAST using default parameters can be utilized as described in Altschul et al. (Altschul 1997, Nucleic Acids Res. 25(17):3389 3402). 4195554_1 (GHMattes) P92082.AU.1 Table 1: Relation of sequence types of querry and hit sequences for various BLASt pro grams Input query sequence Converted Query Algorithm Converted Hit Actual Database DNA BLASTn DNA PRT BLASTp PRT DNA PRT BLASTx PRT PRT tBLASTn PRT DNA DNA PRT tBLASTx PRT DNA A polynucleotide comprising a fragment of any of the aforementioned nucleic acid se 5 quences is also encompassed as a polynucleotide of the present invention. The fragment shall encode a polypeptide which still has acyltransferase activity as specified above. Ac cordingly, the polypeptide may comprise or consist of the domains of the polypeptide of the present invention conferring the said biological activity. A fragment as meant herein, pref erably, comprises at least 50, at least 100, at least 250 or at least 500 consecutive nucleo 10 tides of any one of the aforementioned nucleic acid sequences or encodes an amino acid sequence comprising at least 20, at least 30, at least 50, at least 80, at least 100 or at least 150 consecutive amino acids of any one of the aforementioned amino acid sequences. The variant polynucleotides or fragments referred to above, preferably, encode polypep 15 tides retaining acyltransferase activity to a significant extent, preferably, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90% of the acyltransferase activity exhibited by any of the polypeptide shown in any one of SEQ ID NOs: 2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, 38, 41, 44, 47, 50, 53 , and 56 or derivative of any of these polypeptides. The activity may be tested as 20 described in the accompanying examples. The polynucleotides of the present invention either essentially consist of the aforemen tioned nucleic acid sequences or comprise the aforementioned nucleic acid sequences. Thus, they may contain further nucleic acid sequences as well. Preferably, the polynucleo 25 tide of the present invention may comprise in addition to an open reading frame further un translated sequence at the 3' and at the 5' terminus of the coding gene region: at least 500, preferably 200, more preferably 100 nucleotides of the sequence upstream of the 5' termi nus of the coding region and at least 100, preferably 50, more preferably 20 nucleotides of the sequence downstream of the 3' terminus of the coding gene region. Furthermore, the 30 polynucleotides of the present invention may encode fusion proteins wherein one partner of the fusion protein is a polypeptide being encoded by a nucleic acid sequence recited above. Such fusion proteins may comprise as additional part other enzymes of the fatty acid or 4195554_1 (GHMattes) P92082.AU.1 PUFA biosynthesis pathways, polypeptides for monitoring expression (e.g., green, yellow, blue or red fluorescent proteins, alkaline phosphatase and the like) or so called "tags" which may serve as a detectable marker or as an auxiliary measure for purification purposes. Tags for the different purposes are well known in the art and comprise FLAG-tags, 6 5 histidine-tags, MYC-tags and the like. The polynucleotide of the present invention shall be provided, preferably, either as an iso lated polynucleotide (i.e. purified or at least isolated from its natural context such as its natural gene locus) or in genetically modified or exogenously (i.e. artificially) manipulated 10 form. An isolated polynucleotide can, for example, comprise less than approximately 5 kb, 4 kb, 3 kb, 2 kb, 1 kb, 0.5 kb or 0.1 kb of nucleotide sequences which naturally flank the nu cleic acid molecule in the genomic DNA of the cell from which the nucleic acid is derived. The polynucleotide, preferably, is provided in the form of double or single stranded mole cule. It will be understood that the present invention by referring to any of the aforemen 15 tioned polynucleotides of the invention also refers to complementary or reverse comple mentary strands of the specific sequences or variants thereof referred to before. The polynucleotide encompasses DNA, including cDNA and genomic DNA, or RNA polynucleo tides. 20 However, the present invention also pertains to polynucleotide variants which are derived from the polynucleotides of the present invention and are capable of interefering with the transcription or translation of the polynucleotides of the present invention. Such variant polynucleotides include anti-sense nucleic acids, ribozymes, siRNA molecules, morpholino nucleic acids (phosphorodiamidate morpholino oligos), triple-helix forming oligonucleotides, 25 inhibitory oligonucleotides, or micro RNA molecules all of which shall specifically recognize the polynucleotide of the invention due to the presence of complementary or substantially complementary sequences. These techniques are well known to the skilled artisan. Suitable variant polynucleotides of the aforementioned kind can be readily designed based on the structure of the polynucleotides of this invention. 30 Moreover, comprised are also chemically modified polynucleotides including naturally oc curring modified polynucleotides such as glycosylated or methylated polynucleotides or arti ficial modified ones such as biotinylated polynucleotides. 35 Advantageously, it has been found in accordance with the present invention that the polynucleotides encoding the above mentioned polypeptides having acyltransferase activity and, in particular, LPLAT, LPAAT, DGAT and/or GPAT activity, can be used for the manu facture of PUFA and, in particular, LCPUFA when expressed in a transgenic host organism or cell. Specifically, the aforementioned acyltransferase activities will allow for an increase 4195554_1 (GHMattes) P92082.AU.1 of LCPUFA esterified to triglycerides in seed oils by shifting the said LCPUFA from the acyl CoA pool (by polypeptides having LPAAT, DGAT or GPAT activity as specified above) and/or from the acyl-CoA pool/pospholipid pool to the phospholipid pool/acyl-CoA pool (by polypeptides having LPLAT as specified above) via transesterification. Surprisingly, it was 5 found that the acyltransferases encoded by the polynucleotides of the present invention are also capable of efficiently shifting rather long and highly unsaturated LCPUFA towards the triglyceride pool or between the phospholipid pool and the acyl-CoA pool, in particular, even the long chain intermediates. More surprisingly even, DHA which is known to be incorpo rated in triglycerides only in very low amounts, if at all, can be efficiently transesterified to 10 triglycerides by the acyltransferases of the invention. In particular the LPLAT of the present invention can efficiently catalyse the transesterfica tion of 18:2n-6 from the sn2 position of phosphatidylcholine (PC) to CoA and/or from CoA to lysophosphatidylcholine (LPC), the transesterfication of 18:2n-6 from the sn2 position of 15 phosphatidylethanolamine (PE) to CoA and/or from CoA to lysophosphatidylethanolamine (LPE), the transesterfication of 18:2n-6 from the sn2 position of phosphatidylserine (PS) to CoA and/or from CoA to lysophosphatidylserine (LPS), the transesterfication of 18:3n-6 from the sn2 position of phosphatidylcholine (PC) to CoA and/or from CoA to lysophos phatidylcholine (LPC), the transesterfication of 18:3n-6 from the sn2 position of phosphati 20 dylethanolamine (PE) to CoA and/or from CoA to lysophosphatidylethanolamine (LPE), the transesterfication of 18:3n-6 from the sn2 position of phosphatidylserine (PS) to CoA and/or from CoA to lysophosphatidylserine (LPS), the transesterfication of 18:3n-3 from the sn2 position of phosphatidylcholine (PC) to CoA and/or from CoA to lysophosphatidylcholine (LPC), the transesterfication of 18:3n-3 from the sn2 position of phosphatidylethanolamine 25 (PE) to CoA and/or from CoA to lysophosphatidylethanolamine (LPE), the transesterfication of 18:3n-3 from the sn2 position of phosphatidylserine (PS) to CoA and/or from CoA to lysophosphatidylserine (LPS), transesterfication of 18:4n-3 from the sn2 position of phos phatidylcholine (PC) to CoA and/or from CoA to lysophosphatidylcholine (LPC), the trans esterfication of 18:4n-3 from the sn2 position of phosphatidylethanolamine (PE) to CoA 30 and/or from CoA to lysophosphatidylethanolamine (LPE), the transesterfication of 18:4n-3 from the sn2 position of phosphatidylserine (PS) to CoA and/or from CoA to lysophosphati dylserine (LPS), the transesterfication of 20:3n-6 from the sn2 position of phosphatidylcho line (PC) to CoA and/or from CoA to lysophosphatidylcholine (LPC), the transesterfication of 20:3n-6 from the sn2 position of phosphatidylethanolamine (PE) to CoA and/or from CoA to 35 lysophosphatidylethanolamine (LPE), the transesterfication of 20:3n-6 from the sn2 position of phosphatidylserine (PS) to CoA and/or from CoA to lysophosphatidylserine (LPS), the transesterfication of 20:4n-3 from the sn2 position of phosphatidylcholine (PC) to CoA and/or from CoA to lysophosphatidylcholine (LPC), the transesterfication of 20:4n-3 from the sn2 position of phosphatidylethanolamine (PE) to CoA and/or from CoA to lysophos 4195554_1 (GHMattes) P92082.AU.1 phatidylethanolamine (LPE), the transesterfication of 20:4n-3 from the sn2 position of phos phatidylserine (PS) to CoA and/or from CoA to lysophosphatidylserine (LPS), the trans esterfication of 20:4n-6 from the sn2 position of phosphatidycholine (PC) to CoA and/or from CoA to lysophosphatidylcholine (LPC), the transesterfication of 20:4n-6 from the sn2 5 position of phosphatidylethanolamine (PE) to CoA and/or from CoA to lysophosphati dylethanolamine (LPE), the transesterfication of 20:4n-6 from the sn2 position of phosphati dylserine (PS) to CoA and/or from CoA to lysophosphatidylserine (LPS), the transesterfica tion of 20:5n-3 from the sn2 position of phosphatidycholine (PC) to CoA and/or from CoA to lysophosphatidylcholine (LPC), the transesterfication of 20:5n-3 from the sn2 position of 10 phosphatidylethanolamine (PE) to CoA and/or from CoA to lysophosphatidylethanolamine (LPE), the transesterfication of 20:5n-3 from the sn2 position of phosphatidylserine (PS) to CoA and/or from CoA to lysophosphatidylserine (LPS), the transesterfication of 22:5n-3 from the sn2 position of phosphatidycholine (PC) to CoA and/or from CoA to lysophos phatidylcholine (LPC), the transesterfication of 22:5n-3 from the sn2 position of phosphati 15 dylethanolamine (PE) to CoA and/or from CoA to lysophosphatidylethanolamine (LPE), the transesterfication of 22:5n-3 from the sn2 position of phosphatidylserine (PS) to CoA and/or from CoA to lysophosphatidylserine (LPS), the transesterfication of 22:6n-3 from the sn2 position of phosphatidycholine (PC) to CoA and/or from CoA to lysophosphatidylcholine (LPC), the transesterfication of 22:6n-3 from the sn2 position of phosphatidylethanolamine 20 (PE) to CoA and/or from CoA to lysophosphatidylethanolamine (LPE) and/or the transester fication of 22:6n-3 from the sn2 position of phosphatidylserine (PS) to CoA and/or from CoA to lysophosphatidylserine (LPS). Preferably the LPAAT of the present invention can efficiently catalyse the transesterfication 25 of 18:2n-6 from CoA to the sn2 position of lysophosphatidic acid (LPA), the transesterfica tion of 18:3n-6 from CoA to the sn2 position of lysophosphatidic acid (LPA), the transester fication of 18:3n-3 from CoA to the sn2 position of lysophosphatidic acid (LPA) and/or the transesterfication of 18:4n-6 from CoA to the sn2 position of lysophosphatidic acid (LPA). 30 More preferably the LPAAT of the present invention can efficiently catalyse the transesterfi cation of 20:3n-6 from CoA to the sn2 position of lysophosphatidic acid (LPA), transesterfi cation of 20:4n-3 from CoA to the sn2 position of lysophosphatidic acid (LPA) and/or the transesterfication of 22:5n-3 from CoA to the sn2 position of lysophosphatidic acid (LPA). 35 Most preferably the LPAAT of the present invention can efficiently catalyse the transesterfi cation of 20:4n-6 from CoA to the sn2 position of lysophosphatidic acid (LPA), the trans esterfication of 20:5n-3 from CoA to the sn2 position of lysophosphatidic acid (LPA) and/or the transesterfication of 22:6n-3 from CoA to the sn2 position of lysophosphatidic acid (LPA). 4195554_1 (GHMattes) P92082.AU.1 Preferably the GPAT of the present invention can efficiently catalyse the transesterfication of 18:2n-6 from CoA to the sni position of glycerole-3-phosphate (G3P),the transesterfica tion of 18:3n-6 from CoA to the sni position of glycerole-3-phosphate (G3P), the transester 5 fication of 18:3n-3 from CoA to the sni position of glycerole-3-phosphate (G3P) and/or the transesterfication of 18:4n-6 from CoA to the sni position of glycerole-3-phosphate (G3P). More preferably the GPAT of the present invention can efficiently catalyse the transesterfi cation of 20:3n-6 from CoA to the sni position of glycerole-3-phosphate (G3P), the trans 10 esterfication of 20:4n-3 from CoA to the sni position of glycerole-3-phosphate (G3P) and/or the transesterfication of 22:5n-3 from CoA to the sni position of glycerole-3-phosphate (G3P). Most preferably the GPAT of the present invention can efficiently catalyse the transesterfi 15 cation of 20:4n-6 from CoA to the sni position of glycerole-3-phosphate (G3P), the trans esterfication of 20:5n-3 from CoA to the sni position of glycerole-3-phosphate (G3P) and/or the transesterfication of 22:6n-3 from CoA to the sni position of glycerole-3-phosphate (G3P). 20 Preferably the DGAT of the present invention can efficiently catalyse the transesterfication of 18:2n-6 from CoA to the sn3 position of Diacylglycerol (DAG), transesterfication of 18:3n 6 from CoA to the sn3 position of Diacylglycerol (DAG), the transesterfication of 18:3n-3 from CoA to the sn3 position of Diacylglycerol (DAG) and/or the transesterfication of 18:4n 6 from CoA to the sn3 position of Diacylglycerol (DAG). 25 More preferably the DGAT of the present invention can efficiently catalyse the transesterfi cation of 20:3n-6 from CoA to the sn3 position of Diacylglycerol (DAG), the transesterfica tion of 20:4n-3 from CoA to the sn3 position of Diacylglycerol (DAG) and/or the transesterfi cation of 22:5n-3 from CoA to the sn3 position of Diacylglycerol (DAG). 30 Most preferably the DGAT of the present invention can efficiently catalyse the transesterfi cation of 20:4n-6 from CoA to the sn3 position of Diacylglycerol (DAG), the transesterfica tion of 20:5n-3 from CoA to the sn3 position of Diacylglycerol (DAG) and/or the transesterfi cation of 22:6n-3 from CoA to the sn3 position of Diacylglycerol (DAG). 35 The activity of the LPLAT, LPAAT, GPAT or DGAT of the present invention is useful for the specificity of a fatty acid. This fatty acid specificity is useful to generate an artificially ARA specificity preferably. More preferably the activity of the LPLAT, LPAAT, GPAT or DGAT of the present invention is useful to generate an artificially EPA-specificity. Most preferably the 4195554_1 (GHMattes) P92082.AU.1 activity of the LPLAT, LPAAT, GPAT or DGAT of the present invention is useful to generate an artificially DHA-specificity. In a preferred embodiment of the polynucleotide of the present invention, said polynucleo 5 tide further comprises an expression control sequence operatively linked to the said nucleic acid sequence. The term "expression control sequence" as used herein refers to a nucleic acid sequence which is capable of governing, i.e. initiating and controlling, transcription of a nucleic acid 10 sequence of interest, in the present case the nucleic sequences recited above. Such a se quence usually comprises or consists of a promoter or a combination of a promoter and enhancer sequences. Expression of a polynucleotide comprises transcription of the nucleic acid molecule, preferably, into a translatable mRNA. Additional regulatory elements may include transcriptional as well as translational enhancers. The following promoters and ex 15 pression control sequences may be, preferably, used in an expression vector according to the present invention. The cos, tac, trp, tet, trp-tet, Ipp, lac, Ipp-lac, laclq, T7, T5, T3, gal, trc, ara, SP6, A-PR or A-PL promoters are, preferably, used in Gram-negative bacteria. For Gram-positive bacteria, promoters amy and SPO2 may be used. From yeast or fungal pro moters ADC1, AOX1r, GALl, MFa, AC, P-60, CYC1, GAPDH, TEF, rp28, ADH are, pref 20 erably, used. For animal cell or organism expression, the promoters CMV-, SV40-, RSV promoter (Rous sarcoma virus), CM V-enhancer, SV40-enhancer are preferably used. From plants the promoters CaMV/35S (Franck 1980, Cell 21: 285-294], PRP1 (Ward 1993, Plant. Mol. Biol. 22), SSU, OCS, lib4, usp, STLS1, B33, nos or the ubiquitin or phaseolin pro moter. Also preferred in this context are inducible promoters, such as the promoters de 25 scribed in EP 0 388 186 Al (i.e. a benzylsulfonamide-inducible promoter), Gatz 1992, Plant J. 2:397-404 (i.e. a tetracyclin-inducible promoter), EP 0 335 528 Al ( i.e. a abscisic-acid inducible promoter) or WO 93/21334 (i.e. a ethanol- or cyclohexenol-inducible promoter). Further suitable plant promoters are the promoter of cytosolic FBPase or the ST-LSI pro moter from potato (Stockhaus 1989, EMBO J. 8, 2445), the phosphoribosyl-pyrophosphate 30 amidotransferase promoter from Glycine max (Genbank accession No. U87999) or the node-specific promoter described in EP 0 249 676 Al. Particularly preferred are promoters which enable the expression in tissues which are involved in the biosynthesis of fatty acids. Also particularly preferred are seed-specific promoters such as the USP promoter in accor dance with the practice, but also other promoters such as the LeB4, DC3, phaseolin or 35 napin promoters. Further especially preferred promoters are seed-specific promoters which can be used for monocotyledonous or dicotyledonous plants and which are described in US 5,608,152 (napin promoter from oilseed rape), WO 98/45461 (oleosin promoter from Arabi dopsis, US 5,504,200 (phaseolin promoter from Phaseolus vulgaris), WO 91/13980 (Bce4 promoter from Brassica), by Baeumlein et al., Plant J., 2, 2, 1992:233-239 (LeB4 promoter 4195554_1 (GHMattes) P92082.AU.1 from a legume), these promoters being suitable for dicots. The following promoters are suit able for monocots: Ipt-2 or Ipt-1 promoter from barley (WO 95/15389 and WO 95/23230), hordein promoter from barley and other promoters which are suitable and which are de scribed in WO 99/16890. In principle, it is possible to use all natural promoters together with 5 their regulatory sequences, such as those mentioned above, for the novel process. Like wise, it is possible and advantageous to use synthetic promoters, either additionally or alone, especially when they mediate a seed-specific expression, such as, for example, as described in WO 99/16890. In a particular embodiment, seed-specific promoters are utilized to enhance the production of the desired PUFA or LCPUFA. 10 The term "operatively linked" as used herein means that the expression control sequence and the nucleic acid of interest are linked so that the expression of the said nucleic acid of interest can be governed by the said expression control sequence, i.e. the expression con trol sequence shall be functionally linked to the said nucleic acid sequence to be expressed. 15 Accordingly, the expression control sequence and, the nucleic acid sequence to be ex pressed may be physically linked to each other, e.g., by inserting the expression control sequence at the 5'end of the nucleic acid sequence to be expressed. Alternatively, the ex pression control sequence and the nucleic acid to be expressed may be merely in physical proximity so that the expression control sequence is capable of governing the expression of 20 at least one nucleic acid sequence of interest. The expression control sequence and the nucleic acid to be expressed are, preferably, separated by not more than 500 bp, 300 bp, 100 bp, 80 bp, 60 bp, 40 bp, 20 bp, 10 bp or 5 bp. In a further preferred embodiment of the polynucleotide of the present invention, said 25 polynucleotide further comprises a terminator sequence operatively linked to the nucleic acid sequence. The term "terminator" as used herein refers to a nucleic acid sequence which is capable of terminating transcription. These sequences will cause dissociation of the transcription ma 30 chinery from the nucleic acid sequence to be transcribed. Preferably, the terminator shall be active in plants and, in particular, in plant seeds. Suitable terminators are known in the art and, preferably, include polyadenylation signals such as the SV40-poly-A site or the tk-poly A site or one of the plant specific signals indicated in Loke et al. 2005, Plant Physiol 138, pp. 1457-1468, downstream of the nucleic acid sequence to be expressed. 35 The present invention also relates to a vector comprising the polynucleotide of the present invention. The term "vector", preferably, encompasses phage, plasmid, viral vectors as well as artifi 4195554_1 (GHMattes) P92082.AU.1 cial chromosomes, such as bacterial or yeast artificial chromosomes. Moreover, the term also relates to targeting constructs which allow for random or site- directed integration of the targeting construct into genomic DNA. Such target constructs, preferably, comprise DNA of sufficient length for either homolgous or heterologous recombination as described in detail 5 below. The vector encompassing the polynucleotide of the present invention, preferably, further comprises selectable markers for propagation and/or selection in a host. The vector may be incorporated into a host cell by various techniques well known in the art. If intro duced into a host cell, the vector may reside in the cytoplasm or may be incorporated into the genome. In the latter case, it is to be understood that the vector may further comprise 10 nucleic acid sequences which allow for homologous recombination or heterologous inser tion. Vectors can be introduced into prokaryotic or eukaryotic cells via conventional trans formation or transfection techniques. The terms "transformation" and "transfection", conju gation and transduction, as used in the present context, are intended to comprise a multi plicity of prior-art processes for introducing foreign nucleic acid (for example DNA) into a 15 host cell, including calcium phosphate, rubidium chloride or calcium chloride co precipitation, DEAE-dextran-mediated transfection, lipofection, natural competence, carbon based clusters, chemically mediated transfer, electroporation or particle bombardment. Suitable methods for the transformation or transfection of host cells, including plant cells, can be found in Sambrook et al. (Molecular Cloning: A Laboratory Manual, 2nd ed., Cold 20 Spring Harbor Laboratory, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, 1989) and other laboratory manuals, such as Methods in Molecular Biology, 1995, Vol. 44, Agrobacterium protocols, Ed.: Gartland and Davey, Humana Press, Totowa, New Jersey. Alternatively, a plasmid vector may be introduced by heat shock or electroporation tech niques. Should the vector be a virus, it may be packaged in vitro using an appropriate 25 packaging cell line prior to application to host cells. Preferably, the vector referred to herein is suitable as a cloning vector, i.e. replicable in mi crobial systems. Such vectors ensure efficient cloning in bacteria and, preferably, yeasts or fungi and make possible the stable transformation of plants. Those which must be men 30 tioned are, in particular, various binary and co-integrated vector systems which are suitable for the T-DNA-mediated transformation. Such vector systems are, as a rule, characterized in that they contain at least the vir genes, which are required for the Agrobacterium mediated transformation, and the sequences which delimit the T-DNA (T-DNA border). These vector systems, preferably, also comprise further cis-regulatory regions such as 35 promoters and terminators and/or selection markers with which suitable transformed host cells or organisms can be identified. While co-integrated vector systems have vir genes and T-DNA sequences arranged on the same vector, binary systems are based on at least two vectors, one of which bears vir genes, but no T-DNA, while a second one bears T-DNA, but no vir gene. As a consequence, the last-mentioned vectors are relatively small, easy to ma 4195554_1 (GHMattes) P92082.AU.1 nipulate and can be replicated both in E. coli and in Agrobacterium. These binary vectors include vectors from the pBIB-HYG, pPZP, pBecks, pGreen series. Preferably used in ac cordance with the invention are Bin19, pB1101, pBinAR, pGPTV and pCAMBIA. An over view of binary vectors and their use can be found in Hellens et al, Trends in Plant Science 5 (2000) 5, 446-451. Furthermore, by using appropriate cloning vectors, the polynucleotides can be introduced into host cells or organisms such as plants or animals and, thus, be used in the transformation of plants, such as those which are published, and cited, in: Plant Mo lecular Biology and Biotechnology (CRC Press, Boca Raton, Florida), chapter 6/7, pp. 71 119 (1993); F.F. White, Vectors for Gene Transfer in Higher Plants; in: Transgenic Plants, 10 vol. 1, Engineering and Utilization, Ed.: Kung and R. Wu, Academic Press, 1993, 15-38; B. Jenes et al., Techniques for Gene Transfer, in: Transgenic Plants, vol. 1, Engineering and Utilization, Ed.: Kung and R. Wu, Academic Press (1993), 128-143; Potrykus 1991, Annu. Rev. Plant Physiol. Plant Molec. Biol. 42, 205-225. 15 More preferably, the vector of the present invention is an expression vector. In such an ex pression vector, i.e. a vector which comprises the polynucleotide of the invention having the nucleic acid sequence operatively linked to an expression control sequence (also called "expression cassette") allowing expression in prokaryotic or eukaryotic cells or isolated frac tions thereof. Suitable expression vectors are known in the art such as Okayama-Berg 20 cDNA expression vector pcDV1 (Pharmacia), pCDM8, pRc/CMV, pcDNA1, pcDNA3 (Invi trogene) or pSPORT1 (GIBCO BRL). Further examples of typical fusion expression vectors are pGEX (Pharmacia Biotech Inc; Smith 1988, Gene 67:31-40), pMAL (New England Bio labs, Beverly, MA) and pRIT5 (Pharmacia, Piscataway, NJ), where glutathione S-transferase (GST), maltose E-binding protein and protein A, respectively, are fused with 25 the recombinant target protein. Examples of suitable inducible nonfusion E. coli expression vectors are, inter alia, pTrc (Amann 1988, Gene 69:301-315) and pET 11d (Studier 1990, Methods in Enzymology 185, 60-89). The target gene expression of the pTrc vector is based on the transcription from a hybrid trp-lac fusion promoter by host RNA polymerase. The target gene expression from the pET 11d vector is based on the transcription of a T7 30 gnlO-lac fusion promoter, which is mediated by a coexpressed viral RNA polymerase (T7 gnl). This viral polymerase is provided by the host strains BL21 (DE3) or HMS174 (DE3) from a resident -prophage which harbors a T7 gn1 gene under the transcriptional control of the lacUV 5 promoter. The skilled artisan is familiar with other vectors which are suitable in prokaryotic organisms; these vectors are, for example, in E. coli, pLG338, pACYC184, 35 the pBR series such as pBR322, the pUC series such as pUC18 or pUC19, the M113mp series, pKC30, pRep4, pHS1, pHS2, pPLc236, pMBL24, pLG200, pUR290, plN-111113-B1, gtll or pBdCl, in Streptomyces plJ101, plJ364, plJ702 or plJ361, in Bacillus pUB110, pC194 or pBD214, in Corynebacterium pSA77 or pAJ667. Examples of vectors for expres sion in the yeast S. cerevisiae comprise pYep Seci (Baldari 1987, Embo J. 6:229-234), 4195554_1 (GHMattes) P92082.AU.1 pMFa (Kurjan 1982, Cell 30:933-943), pJRY88 (Schultz 1987, Gene 54:113-123) and pYES2 (Invitrogen Corporation, San Diego, CA). Vectors and processes for the construction of vectors which are suitable for use in other fungi, such as the filamentous fungi, comprise those which are described in detail in: van den Hondel, C.A.M.J.J., & Punt, P.J. (1991) 5 "Gene transfer systems and vector development for filamentous fungi, in: Applied Molecular Genetics of fungi, J.F. Peberdy et al., Ed., pp. 1-28, Cambridge University Press: Cam bridge, or in: More Gene Manipulations in Fungi (J.W. Bennett & L.L. Lasure, Ed., pp. 396 428: Academic Press: San Diego). Further suitable yeast vectors are, for example, pAG-1, YEp6, YEp13 or pEMBLYe23. As an alternative, the polynucleotides of the present inven 10 tion can be also expressed in insect cells using baculovirus expression vectors. Baculovirus vectors which are available for the expression of proteins in cultured insect cells (for exam ple Sf9 cells) comprise the pAc series (Smith 1983, Mol. Cell Biol. 3:2156-2165) and the pVL series (Lucklow 1989, Virology 170:31-39). 15 The polynucleotide of the present invention can be expressed in single-cell plant cells (such as algae), see Falciatore 1999, Marine Biotechnology 1 (3):239-251 and the references cited therein, and plant cells from higher plants (for example Spermatophytes, such as ar able crops) by using plant expression vectors. Examples of plant expression vectors com prise those which are described in detail in: Becker 1992, Plant Mol. Biol. 20:1195-1197; 20 Bevan 1984, Nucl. Acids Res. 12:8711-8721; Vectors for Gene Transfer in Higher Plants; in: Transgenic Plants, Vol. 1, Engineering and Utilization, Ed.: Kung and R. Wu, Academic Press, 1993, p. 15-38. A plant expression cassette, preferably, comprises regulatory se quences which are capable of controlling the gene expression in plant cells and which are functionally linked so that each sequence can fulfill its function, such as transcriptional ter 25 mination, for example polyadenylation signals. Preferred polyadenylation signals are those which are derived from Agrobacterium tumefaciens T-DNA, such as the gene 3 of the Ti plasmid pTiACH5, which is known as octopine synthase (Gielen 1984, EMBO J. 3, 835) or functional equivalents of these, but all other terminators which are functionally active in plants are also suitable. Since plant gene expression is very often not limited to transcrip 30 tional levels, a plant expression cassette preferably comprises other functionally linked se quences such as translation enhancers, for example the overdrive sequence, which com prises the 5-untranslated tobacco mosaic virus leader sequence, which increases the pro tein/RNA ratio (Gallie 1987, Nucl. Acids Research 15:8693-8711). As described above, plant gene expression must be functionally linked to a suitable promoter which performs the 35 expression of the gene in a timely, cell-specific or tissue-specific manner. Promoters which can be used are constitutive promoters (Benfey 1989, EMBO J. 8:2195-2202) such as those which are derived from plant viruses such as 35S CAMV (Franck 1980, Cell 21:285 294), 19S CaMV (see US 5,352,605 and WO 84/02913) or plant promoters such as the promoter of the Rubisco small subunit, which is described in US 4,962,028. Other preferred 4195554_1 (GHMattes) P92082.AU.1 sequences for the use in functional linkage in plant gene expression cassettes are targeting sequences which are required for targeting the gene product into its relevant cell compart ment (for a review, see Kermode 1996, Crit. Rev. Plant Sci. 15, 4: 285-423 and references cited therein), for example into the vacuole, the nucleus, all types of plastids, such as amy 5 loplasts, chloroplasts, chromoplasts, the extracellular space, the mitochondria, the endo plasmic reticulum, oil bodies, peroxisomes and other compartments of plant cells. As de scribed above, plant gene expression can also be facilitated via a chemically inducible pro moter (for a review, see Gatz 1997, Annu. Rev. Plant Physiol. Plant Mol. Biol., 48:89-108). Chemically inducible promoters are particularly suitable if it is desired that genes are ex 10 pressed in a time-specific manner. Examples of such promoters are a salicylic-acid inducible promoter (WO 95/19443), a tetracyclin-inducible promoter (Gatz 1992, Plant J. 2, 397-404) and an ethanol-inducible promoter. Promoters which respond to biotic or abiotic stress conditions are also suitable promoters, for example the pathogen-induced PRP1 gene promoter (Ward 1993, Plant Mol. Biol. 22:361-366), the heat-inducible hsp80 promoter 15 from tomato (US 5,187,267), the cold-inducible alpha-amylase promoter from potato (WO 96/12814) or the wound-inducible pinll promoter (EP 0 375 091 A). The promoters which are especially preferred are those which bring about the expression of genes in tissues and organs in which fatty acid, lipid and oil biosynthesis takes place, in seed cells such as the cells of endosperm and of the developing embryo. Suitable promoters are the napin gene 20 promoter from oilseed rape (US 5,608,152), the USP promoter from Vicia faba (Baeumlein 1991, Mol. Gen. Genet. 225 (3):459-67), the oleosin promoter from Arabidopsis (WO 98/45461), the phaseolin promoter from Phaseolus vulgaris (US 5,504,200), the Bce4 pro moter from Brassica (WO 91/13980) or the legumin B4 promoter (LeB4; Baeumlein 1992, Plant Journal, 2 (2):233-9), and promoters which bring about the seed-specific expression 25 in monocotyledonous plants such as maize, barley, wheat, rye, rice and the like. Suitable promoters to be taken into consideration are the lpt2 or Ipt1 gene promoter from barley (WO 95/15389 and WO 95/23230) or those which are described in WO 99/16890 (promoters from the barley hordein gene, the rice glutelin gene, the rice oryzin gene, the rice prolamin gene, the wheat gliadin gene, wheat glutelin gene, the maize zein gene, the oat glutelin 30 gene, the sorghum kasirin gene, the rye secalin gene). Likewise, especially suitable are promoters which bring about the plastid-specific expression since plastids are the compart ment in which the precursors and some end products of lipid biosynthesis are synthesized. Suitable promoters such as the viral RNA-polymerase promoter are described in WO 95/16783 and WO 97/06250, and the clpP promoter from Arabidopsis, described in WO 35 99/46394. The abovementioned vectors are only a small overview of vectors to be used in accordance with the present invention. Further vectors are known to the skilled artisan and are de scribed, for example, in: Cloning Vectors (Ed., Pouwels, P.H., et al., Elsevier, Amsterdam 4195554_1 (GHMattes) P92082.AU.1 New York-Oxford, 1985, ISBN 0 444 904018). For further suitable expression systems for prokaryotic and eukaryotic cells see the chapters 16 and 17 of Sambrook, loc cit. It follows from the above that, preferably, said vector is an expression vector. More prefera 5 bly, the said polynucleotide of the present invention is under the control of a seed-specific promoter in the vector of the present invention. A preferred seed-specific promoter as meant herein is selected from the group consisting of Conlinin 1, Conlinin 2, napin, LuFad3, USP, LeB4, Arc, Fae, ACP, LuPXR, and SBP. For details, see, e.g., US 2003-0159174. 10 Moreover, the present invention relates to a host cell comprising the polynucleotide or the vector of the present invention. Preferably, said host cell is a plant cell and, more preferably, a plant cell obtained from an oilseed crop. More preferably, said oilseed crop is selected from the group consisting of flax 15 (Linum sp.), rapeseed (Brassica sp.), soybean (Glycine and Soja sp.), sunflower (Helian thus sp.), cotton (Gossypium sp.), corn (Zea mays), olive (Olea sp.), safflower (Carthamus sp.), cocoa (Theobroma cacoa), peanut (Arachis sp.), hemp, camelina, crambe, oil palm, coconuts, groundnuts, sesame seed, castor bean, lesquerella, tallow tree, sheanuts, tung nuts, kapok fruit, poppy seed, jojoba seeds and perilla. 20 Also preferably, said host cell is a microorganism. More preferably, said microorganism is a bacterium, a fungus or algae. More preferably, it is selected from the group consisting of Candida, Cryptococcus, Lipomyces, Rhodosporidium, Yarrowia and Schizochytrium. 25 Moreover, a host cell according to the present invention may also be an animal cell. Pref erably, said animal host cell is a host cell of a fish or a cell line obtained therefrom. More preferably, the fish host cell is from herring, salmon, sardine, redfish, eel, carp, trout, hali but, mackerel, zander or tuna. 30 It will be understood that if the host cell of the invention shall be applied for LCPUFA pro duction, it shall be capable of carrying out desaturation and elongation steps on fatty acids. To produce the LCPUFA according to the invention, the C16- or C18- fatty acids must first be desaturated by the enzymatic activity of a desaturase and subsequently be elongated by at least two carbon atoms via an elongase. After one elongation cycle, this enzyme activity 35 gives C18- or C20-fatty acids and after two or three elongation cycles C22- or C24-fatty acids. The activity of the desaturases and elongases used in the process according to the invention preferably leads to C18-, C20-, C22- and/or C24-fatty acids, advantageously with at least two double bonds in the fatty acid molecule, preferably with three, four or five dou ble bonds, especially preferably to give C20- and/or C22-fatty acids with at least two double 4195554_1 (GHMattes) P92082.AU.1 bonds in the fatty acid molecule, preferably with three, four or five double bonds in the molecule. After a first desaturation and the elongation have taken place, further desatura tion steps such as, for example, one in the delta-5 position may take place. Products of the process according to the invention which are especially preferred are DGLA, ARA, EPA 5 DPA and/or DHA, most preferably EPA and/or DHA. Desaturases and elongases which are required for this process may not always be present naturally in the host cell. Accordingly, the present invention, preferably, envisages a host cell which in addition to the polynucleo tide of the present invention comprises polynucleotides encoding such desaturases and/or elongases as required depending on the selected organism. Preferred desaturases and/or 10 elongases which shall be present in the host cell are at least one enzyme selected from the group consisting of: A-4-desaturase, A-5-desaturase, A-5-elongase, A-6-desaturase, A12 desaturase, A15-desaturase, o3-desaturase and A-6-elongase. Especially prefered are the bifunctional d12d15-Desaturases dl2d15Des(Ac) from Acanthamoeba castellanii (W02007042510), dl2dl5Des(Cp) from Claviceps purpurea (W02008006202) and 15 dl2dl5Des(Lg)l from Lottia gigantea (W02009016202), the d12-Desaturases d12Des(Co) from Calendula officinalis (W0200185968), d12Des(Lb) from Laccaria bicolor (W02009016202), d12Des(Mb) from Monosiga brevicollis (W02009016202), d12Des(Mg) from Mycosphaerella graminicola (W02009016202), dl2Des(Nh) from Nectria haemato cocca (W02009016202), d12Des(Ol) from Ostreococcus lucimarinus (W02008040787), 20 d12Des(Pb) from Phycomyces blakesleeanus (W02009016202), d12Des(Ps) from Phy tophthora sojae (W02006100241) and d12Des(Tp) from Thalassiosira pseudonana (W02006069710), the d15-Desaturases d15Des(Hr) from Helobdella robusta (W02009016202), d15Des(Mc) from Microcoleus chthonoplastes (W02009016202), d15Des(Mf) from Mycosphaerella fijiensis (W02009016202), d15Des(Mg) from Mycosphae 25 rella graminicola (W02009016202) and dl5Des(Nh)2 from Nectria haematococca (W02009016202), the d4-Desaturases d4Des(Eg) from Euglena gracilis (W02004090123), d4Des(Tc) from Thraustochytrium sp. (W02002026946) and d4Des(Tp) from Thalassiosira pseudonana (W02006069710), the d5-Desaturases d5Des(OI)2 from Ostreococcus lucima rinus (W02008040787), d5Des(Pp) from Physcomitrella patens (W02004057001), 30 d5Des(Pt) from Phaeodactylum tricornutum (W02002057465), d5Des(Tc) from Thrausto chytrium sp. (W02002026946), d5Des(Tp) from Thalassiosira pseudonana (W02006069710) and the d6-Desaturases d6Des(Cp) from Ceratodon purpureus (W02000075341), d6Des(Ol) from Ostreococcus lucimarinus (W02008040787), d6Des(Ot) from Ostreococcus tauri (W02006069710), d6Des(Pf) from Primula farinosa 35 (W02003072784), d6Des(Pir)_BO from Pythium irregulare (W02002026946), d6Des(Pir) from Pythium irregulare (W02002026946), d6Des(Plu) from Primula luteola (W02003072784), d6Des(Pp) from Physcomitrella patens (W0200102591), d6Des(Pt) from Phaeodactylum tricornutum (W02002057465), d6Des(Pv) from Primula vialii (W02003072784) and d6Des(Tp) from Thalassiosira pseudonana (W02006069710), the 4195554_1 (GHMattes) P92082.AU.1 d8-Desaturases d8Des(Ac) from Acanthamoeba castellanii (EP1790731), d8Des(Eg) from Euglena gracilis (W0200034439) and d8Des(Pm) from Perkinsus marinus (W02007093776), the o3-Desaturases o3Des(Pi) from Phytophthora infestans (W02005083053), o3Des(Pir) from Pythium irregulare (W02008022963), o3Des(Pir)2 from 5 Pythium irregulare (W02008022963) and o3Des(Ps) from Phytophthora sojae (W02006100241), the bifunctional d5d6-elongases d5d6Elo(Om)2 from Oncorhynchus my kiss (W02005012316), d5d6Elo(Ta) from Thraustochytrium aureum (W02005012316) and d5d6Elo(Tc) from Thraustochytrium sp. (W02005012316), the d5-elongases d5Elo(At) from Arabidopsis thaliana (W02005012316), d5Elo(At)2 from Arabidopsis thaliana 10 (W02005012316), d5EIo(Ci) from Ciona intestinalis (W02005012316), d5Elo(Ol) from Os treococcus lucimarinus (W02008040787), d5Elo(Ot) from Ostreococcus tauri (W02005012316), d5EIo(Tp) from Thalassiosira pseudonana (W02005012316) and d5Elo(XI) from Xenopus laevis (W02005012316), the d6-elongases d6Elo(Ol) from Ostreo coccus lucimarinus (W02008040787), d6Elo(Ot) from Ostreococcus tauri 15 (W02005012316), d6EIo(Pi) from Phytophthora infestans (W02003064638), d6Elo(Pir) from Pythium irregulare (W02009016208), d6Elo(Pp) from Physcomitrella patens (W02001059128), d6Elo(Ps) from Phytophthora sojae (W02006100241), d6Elo(Ps)2 from Phytophthora sojae (W02006100241), d6Elo(Ps)3 from Phytophthora sojae (W02006100241), d6Elo(Pt) from Phaeodactylum tricornutum (W02005012316), d6Elo(Tc) 20 from Thraustochytrium sp. (W02005012316) and d6Elo(Tp) from Thalassiosira pseudona na (W02005012316), the d9-elongases d9Elo(Ig) from Isochrysis galbana (W02002077213), d9EIo(Pm) from Perkinsus marinus (W02007093776) and d9Elo(Ro) from Rhizopus oryzae (W02009016208). 25 The present invention also relates to a cell, preferably a host cell as specified above or a cell of a non-human organism specified elsewhere herein, said cell comprising a polynu cleotide which is obtained from the polynucleotide of the present invention by a point muta tion, a truncation, an inversion, a deletion, an addition, a substitution and homologous re combination. How to carry out such modifications to a polynucleotide is well known to the 30 skilled artisan and has been described elsewhere in this specification in detail. The present invention furthermore relates to a method for the manufacture of a polypeptide encoded by a polynucleotide of any the present invention comprising a) cultivating the host cell of the invention under conditions which allow for the production 35 of said polypeptide; and b) obtaining the polypeptide from the host cell of step a). Suitable conditions which allow for expression of the polynucleotide of the invention com prised by the host cell depend on the host cell as well as the expression control sequence 4195554_1 (GHMattes) P92082.AU.1 used for governing expression of the said polynucleotide. These conditions and how to se lect them are very well known to those skilled in the art. The expressed polypeptide may be obtained, for example, by all conventional purification techniques including affinity chroma tography, size exclusion chromatography, high pressure liquid chromatography (HPLC) and 5 precipitation techniques including antibody precipitation. It is to be understood that the method may - although preferred - not necessarily yield an essentially pure preparation of the polypeptide. It is to be understood that depending on the host cell which is used for the aforementioned method, the polypeptides produced thereby may become posttranslation ally modified or processed otherwise. 10 The present invention encompasses a polypeptide encoded by the polynucleotide of the present invention or which is obtainable by the aforementioned method. The term "polypeptide" as used herein encompasses essentially purified polypeptides or 15 polypeptide preparations comprising other proteins in addition. Further, the term also re lates to the fusion proteins or polypeptide fragments being at least partially encoded by the polynucleotide of the present invention referred to above. Moreover, it includes chemically modified polypeptides. Such modifications may be artificial modifications or naturally occur ring modifications such as phosphorylation, glycosylation, myristylation and the like (Review 20 in Mann 2003, Nat. Biotechnol. 21, 255-261, review with focus on plants in Huber 2004, Curr. Opin. Plant Biol. 7, 318-322). Currently, more than 300 posttranslational modifications are known (see full ABFRC Delta mass list at http://www.abrf.org/index.cfm/dm.home). The polypeptide of the present invention shall exhibit the acyltransferase activities referred to above. 25 The present invention furthermore relates to an antibody or a fragment derived thereof as an antigen which specifically recognizes a polypeptide encoded by the nucleic acid se quences of the invention. 30 Antibodies against the polypeptides of the invention can be prepared by well known meth ods using a purified polypeptide according to the invention or a suitable fragment derived therefrom as an antigen. A fragment which is suitable as an antigen may be identified by antigenicity determining algorithms well known in the art. Such fragments may be obtained either from the polypeptide of the invention by proteolytic digestion or may be a synthetic 35 peptide. Preferably, the antibody of the present invention is a monoclonal antibody, a poly clonal antibody, a single chain antibody, a chimerized antibody or a fragment of any of these antibodies, such as Fab, Fv or scFv fragments etc.. Also comprised as antibodies by the present invention are bispecific antibodies, synthetic antibodies or chemically modified derivatives of any of the aforementioned antibodies. The antibody of the present invention 4195554_1 (GHMattes) P92082.AU.1 shall specifically bind (i.e. does significantly not cross react with other polypeptides or pep tides) to the polypeptide of the invention. Specific binding can be tested by various well known techniques. Antibodies or fragments thereof can be obtained by using methods which are described, e.g., in Harlow and Lane "Antibodies, A Laboratory Manual", CSH 5 Press, Cold Spring Harbor, 1988. Monoclonal antibodies can be prepared by the techniques originally described in K6hler 1975, Nature 256, 495, and Galfr6 1981, Meth. Enzymol. 73, 3, which comprise the fusion of mouse myeloma cells to spleen cells derived from immu nized mammals. The antibodies can be used, for example, for the immunoprecipitation, immunolocalization or purification (e.g., by affinity chromatography) of the polypeptides of 10 the invention as well as for the monitoring of the presence of said variant polypeptides, for example, in recombinant organisms, and for the identification of proteins or compounds in teracting with the proteins according to the invention. Moreover, the present invention contemplates a non-human transgenic organism compris 15 ing the polynucleotide or the vector of the present invention. Preferably, the non-human transgenic organism is a microorganism, more preferably the non-human transgenic organism is a fungus and most preferably the non-human transgenic organism is a plant, plant part, or plant seed. Preferred plants to be used for introducing the 20 polynucleotide or the vector of the invention are plants which are capable of synthesizing fatty acids, such as all dicotyledonous or monocotyledonous plants, algae or mosses. It is to be understood that host cells derived from a plant may also be used for producing a plant according to the present invention. Preferred plants are selected from the group of the plant families Adelotheciaceae, Anacardiaceae, Asteraceae, Apiaceae, Betulaceae, Boragina 25 ceae, Brassicaceae, Bromeliaceae, Caricaceae, Cannabaceae, Convolvulaceae, Chenopo diaceae, Crypthecodiniaceae, Cucurbitaceae, Ditrichaceae, Elaeagnaceae, Ericaceae, Eu phorbiaceae, Fabaceae, Geraniaceae, Gramineae, Juglandaceae, Lauraceae, Legumino sae, Linaceae, Prasinophyceae or vegetable plants or ornamentals such as Tagetes. Ex amples which may be mentioned are the following plants selected from the group consisting 30 of: Adelotheciaceae such as the genera Physcomitrella, such as the genus and species Physcomitrella patens, Anacardiaceae such as the genera Pistacia, Mangifera, Anacar dium, for example the genus and species Pistacia vera [pistachio], Mangifer indica [mango] or Anacardium occidentale [cashew], Asteraceae, such as the genera Calendula, Cartha mus, Centaurea, Cichorium, Cynara, Helianthus, Lactuca, Locusta, Tagetes, Valeriana, for 35 example the genus and species Calendula officinalis [common marigold], Carthamus tincto rius [safflower], Centaurea cyanus [cornflower], Cichorium intybus [chicory], Cynara scoly mus [artichoke], Helianthus annus [sunflower], Lactuca sativa, Lactuca crispa, Lactuca es culenta, Lactuca scariola L. ssp. sativa, Lactuca scariola L. var. integrata, Lactuca scariola L. var. integrifolia, Lactuca sativa subsp. romana, Locusta communis, Valeriana locusta 4195554_1 (GHMattes) P92082.AU.1 [salad vegetables], Tagetes lucida, Tagetes erecta or Tagetes tenuifolia [african or french marigold], Apiaceae, such as the genus Daucus, for example the genus and species Dau cus carota [carrot], Betulaceae, such as the genus Corylus, for example the genera and species Corylus avellana or Corylus colurna [hazelnut], Boraginaceae, such as the genus 5 Borago, for example the genus and species Borago officinalis [borage], Brassicaceae, such as the genera Brassica, Melanosinapis, Sinapis, Arabadopsis, for example the genera and species Brassica napus, Brassica rapa ssp. [oilseed rape], Sinapis arvensis Brassica juncea, Brassica juncea var. juncea, Brassica juncea var. crispifolia, Brassica juncea var. foliosa, Brassica nigra, Brassica sinapioides, Melanosinapis communis [mustard], Brassica 10 oleracea [fodder beet] or Arabidopsis thaliana, Bromeliaceae, such as the genera Anana, Bromelia (pineapple), for example the genera and species Anana comosus, Ananas ananas or Bromelia comosa [pineapple], Caricaceae, such as the genus Carica, such as the genus and species Carica papaya [pawpaw], Cannabaceae, such as the genus Cannabis, such as the genus and species Cannabis sativa [hemp], Convolvulaceae, such as the genera 15 lpomea, Convolvulus, for example the genera and species lpomoea batatus, lpomoea pan durata, Convolvulus batatas, Convolvulus tiliaceus, lpomoea fastigiata, lpomoea tiliacea, lpomoea triloba or Convolvulus panduratus [sweet potato, batate], Chenopodiaceae, such as the genus Beta, such as the genera and species Beta vulgaris, Beta vulgaris var. altis sima, Beta vulgaris var.Vulgaris, Beta maritima, Beta vulgaris var. perennis, Beta vulgaris 20 var. conditiva or Beta vulgaris var. esculenta [sugarbeet], Crypthecodiniaceae, such as the genus Crypthecodinium, for example the genus and species Cryptecodinium cohnii, Cucur bitaceae, such as the genus Cucurbita, for example the genera and species Cucurbita maxima, Cucurbita mixta, Cucurbita pepo or Cucurbita moschata [pumpkin/squash], Cym bellaceae such as the genera Amphora, Cymbella, Okedenia, Phaeodactylum, Reimeria, 25 for example the genus and species Phaeodactylum tricornutum, Ditrichaceae such as the genera Ditrichaceae, Astomiopsis, Ceratodon, Chrysoblastella, Ditrichum, Distichium, Ec cremidium, Lophidion, Philibertiella, Pleuridium, Saelania, Trichodon, Skottsbergia, for ex ample the genera and species Ceratodon antarcticus, Ceratodon columbiae, Ceratodon heterophyllus, Ceratodon purpureus, Ceratodon purpureus, Ceratodon purpureus 30 ssp. convolutus, Ceratodon, purpureus spp. stenocarpus, Ceratodon purpureus var. rotun difolius, Ceratodon ratodon, Ceratodon stenocarpus, Chrysoblastella chilensis, Ditrichum ambiguum, Ditrichum brevisetum, Ditrichum crispatissimum, Ditrichum difficile, Ditrichum falcifolium, Ditrichum flexicaule, Ditrichum giganteum, Ditrichum heteromallum, Ditrichum lineare, Ditrichum lineare, Ditrichum montanum, Ditrichum montanum, Ditrichum pallidum, 35 Ditrichum punctulatum, Ditrichum pusillum, Ditrichum pusillum var. tortile, Ditrichum rhyn chostegium, Ditrichum schimperi, Ditrichum tortile, Distichium capillaceum, Distichium hagenii, Distichium inclinatum, Distichium macounii, Eccremidium floridanum, Eccremidium whiteleggei, Lophidion strictus, Pleuridium acuminatum, Pleuridium alternifolium, Pleuridium holdridgei, Pleuridium mexicanum, Pleuridium ravenelii, Pleuridium subulatum, Saelania 4195554_1 (GHMattes) P92082.AU.1 glaucescens, Trichodon borealis, Trichodon cylindricus or Trichodon cylindricus var. ob longus, Elaeagnaceae such as the genus Elaeagnus, for example the genus and species Olea europaea [olive], Ericaceae such as the genus Kalmia, for example the genera and species Kalmia latifolia, Kalmia angustifolia, Kalmia microphylla, Kalmia polifolia, Kalmia 5 occidentalis, Cistus chamaerhodendros or Kalmia lucida [mountain laurel], Euphorbiaceae such as the genera Manihot, Janipha, Jatropha, Ricinus, for example the genera and spe cies Manihot utilissima, Janipha manihot, Jatropha manihot, Manihot aipil, Manihot dulcis, Manihot manihot, Manihot melanobasis, Manihot esculenta [manihot] or Ricinus communis [castor-oil plant], Fabaceae such as the genera Pisum, Albizia, Cathormion, Feuillea, Inga, 10 Pithecolobium, Acacia, Mimosa, Medicajo, Glycine, Dolichos, Phaseolus, Soja, for example the genera and species Pisum sativum, Pisum arvense, Pisum humile [pea], Albizia berteri ana, Albizia julibrissin, Albizia lebbeck, Acacia berteriana, Acacia littoralis, Albizia berteri ana, Albizzia berteriana, Cathormion berteriana, Feuillea berteriana, Inga fragrans, Pithe cellobium berterianum, Pithecellobium fragrans, Pithecolobium berterianum, Pseudalbizzia 15 berteriana, Acacia julibrissin, Acacia nemu, Albizia nemu, Feuilleea julibrissin, Mimosa julibrissin, Mimosa speciosa, Sericanrda julibrissin, Acacia lebbeck, Acacia macrophylla, Albizia lebbek, Feuilleea lebbeck, Mimosa lebbeck, Mimosa speciosa [silk tree], Medicago sativa, Medicago falcata, Medicago varia [alfalfa], Glycine max Dolichos soja, Glycine gracilis, Glycine hispida, Phaseolus max, Soja hispida or Soja max [soybean], Funariaceae 20 such as the genera Aphanorrhegma, Entosthodon, Funaria, Physcomitrella, Physcomitrium, for example the genera and species Aphanorrhegma serratum, Entosthodon attenuatus, Entosthodon bolanderi, Entosthodon bonplandii, Entosthodon californicus, Entosthodon drummondii, Entosthodon jamesonii, Entosthodon leibergii, Entosthodon neoscoticus, En tosthodon rubrisetus, Entosthodon spathulifolius, Entosthodon tucsoni, Funaria americana, 25 Funaria bolanderi, Funaria calcarea, Funaria californica, Funaria calvescens, Funaria con voluta, Funaria flavicans, Funaria groutiana, Funaria hygrometrica, Funaria hygrometrica var. arctica, Funaria hygrometrica var. calvescens, Funaria hygrometrica var. convoluta, Funaria hygrometrica var. muralis, Funaria hygrometrica var. utahensis, Funaria mi crostoma, Funaria microstoma var. obtusifolia, Funaria muhlenbergii, Funaria orcuttii, Fu 30 naria plano-convexa, Funaria polaris, Funaria ravenelii, Funaria rubriseta, Funaria serrata, Funaria sonorae, Funaria sublimbatus, Funaria tucsoni, Physcomitrella californica, Phy scomitrella patens, Physcomitrella readeri, Physcomitrium australe, Physcomitrium califor nicum, Physcomitrium collenchymatum, Physcomitrium coloradense, Physcomitrium cu puliferum, Physcomitrium drummondii, Physcomitrium eurystomum, Physcomitrium flexi 35 folium, Physcomitrium hookeri, Physcomitrium hookeri var. serratum, Physcomitrium im mersum, Physcomitrium kellermanii, Physcomitrium megalocarpum, Physcomitrium pyri forme, Physcomitrium pyriforme var. serratum, Physcomitrium rufipes, Physcomitrium sandbergii, Physcomitrium subsphaericum, Physcomitrium washingtoniense, Geraniaceae, such as the genera Pelargonium, Cocos, Oleum, for example the genera and species Co 4195554_1 (GHMattes) P92082.AU.1 cos nucifera, Pelargonium grossularioides or Oleum cocois [coconut], Gramineae, such as the genus Saccharum, for example the genus and species Saccharum officinarum, Juglan daceae, such as the genera Juglans, Wallia, for example the genera and species Juglans regia, Juglans ailanthifolia, Juglans sieboldiana, Juglans cinerea, Wallia cinerea, Juglans 5 bixbyi, Juglans californica, Juglans hindsii, Juglans intermedia, Juglans jamaicensis, Jug lans major, Juglans microcarpa, Juglans nigra or Wallia nigra [walnut], Lauraceae, such as the genera Persea, Laurus, for example the genera and species Laurus nobilis [bay], Per sea americana, Persea gratissima or Persea persea [avocado], Leguminosae, such as the genus Arachis, for example the genus and species Arachis hypogaea [peanut], Linaceae, 10 such as the genera Linum, Adenolinum, for example the genera and species Linum usita tissimum, Linum humile, Linum austriacum, Linum bienne, Linum angustifolium, Linum ca tharticum, Linum flavum, Linum grandiflorum, Adenolinum grandiflorum, Linum lewisii, Linum narbonense, Linum perenne, Linum perenne var. lewisii, Linum pratense or Linum trigynum [linseed], Lythrarieae, such as the genus Punica, for example the genus and spe 15 cies Punica granatum [pomegranate], Malvaceae, such as the genus Gossypium, for ex ample the genera and species Gossypium hirsutum, Gossypium arboreum, Gossypium barbadense, Gossypium herbaceum or Gossypium thurberi [cotton], Marchantiaceae, such as the genus Marchantia, for example the genera and species Marchantia berteroana, Mar chantia foliacea, Marchantia macropora, Musaceae, such as the genus Musa, for example 20 the genera and species Musa nana, Musa acuminata, Musa paradisiaca, Musa spp. [ba nana], Onagraceae, such as the genera Camissonia, Oenothera, for example the genera and species Oenothera biennis or Camissonia brevipes [evening primrose], Palmae, such as the genus Elacis, for example the genus and species Elaeis guineensis [oil palm], Pa paveraceae, such as the genus Papaver, for example the genera and species Papaver ori 25 entale, Papaver rhoeas, Papaver dubium [poppy], Pedaliaceae, such as the genus Sesamum, for example the genus and species Sesamum indicum [sesame], Piperaceae, such as the genera Piper, Artanthe, Peperomia, Steffensia, for example the genera and species Piper aduncum, Piper amalago, Piper angustifolium, Piper auritum, Piper betel, Piper cubeba, Piper longum, Piper nigrum, Piper retrofractum, Artanthe adunca, Artanthe 30 elongata, Peperomia elongata, Piper elongatum, Steffensia elongata [cayenne pepper], Poaceae, such as the genera Hordeum, Secale, Avena, Sorghum, Andropogon, Holcus, Panicum, Oryza, Zea (maize), Triticum, for example the genera and species Hordeum vul gare, Hordeum jubatum, Hordeum murinum, Hordeum secalinum, Hordeum distichon, Hor deum aegiceras, Hordeum hexastichon, Hordeum hexastichum, Hordeum irregulare, Hor 35 deum sativum, Hordeum secalinum [barley], Secale cereale [rye], Avena sativa, Avena fatua, Avena byzantina, Avena fatua var. sativa, Avena hybrida [oats], Sorghum bicolor, Sorghum halepense, Sorghum saccharatum, Sorghum vulgare, Andropogon drummondii, Holcus bicolor, Holcus sorghum, Sorghum aethiopicum, Sorghum arundinaceum, Sorghum caffrorum, Sorghum cernuum, Sorghum dochna, Sorghum drummondii, Sorghum durra, 4195554_1 (GHMattes) P92082.AU.1 Sorghum guineense, Sorghum lanceolatum, Sorghum nervosum, Sorghum saccharatum, Sorghum subglabrescens, Sorghum verticilliflorum, Sorghum vulgare, Holcus halepensis, Sorghum miliaceum, Panicum militaceum [millet], Oryza sativa, Oryza latifolia [rice], Zea mays [maize], Triticum aestivum, Triticum durum, Triticum turgidum, Triticum hybernum, 5 Triticum macha, Triticum sativum or Triticum vulgare [wheat], Porphyridiaceae, such as the genera Chroothece, Flintiella, Petrovanella, Porphyridium, Rhodella, Rhodosorus, Van hoeffenia, for example the genus and species Porphyridium cruentum, Proteaceae, such as the genus Macadamia, for example the genus and species Macadamia intergrifolia [maca damia], Prasinophyceae such as the genera Nephroselmis, Prasinococcus, Scherffelia, Tet 10 raselmis, Mantoniella, Ostreococcus, for example the genera and species Nephroselmis olivacea, Prasinococcus capsulatus, Scherffelia dubia, Tetraselmis chui, Tetraselmis suecica, Mantoniella squamata, Ostreococcus tauri, Rubiaceae such as the genus Cofea, for example the genera and species Cofea spp., Coffea arabica, Coffea canephora or Cof fea liberica [coffee], Scrophulariaceae such as the genus Verbascum, for example the gen 15 era and species Verbascum blattaria, Verbascum chaixii, Verbascum densiflorum, Verbas cum lagurus, Verbascum longifolium, Verbascum lychnitis, Verbascum nigrum, Verbascum olympicum, Verbascum phlomoides, Verbascum phoenicum, Verbascum pulverulentum or Verbascum thapsus [mullein], Solanaceae such as the genera Capsicum, Nicotiana, So lanum, Lycopersicon, for example the genera and species Capsicum annuum, Capsicum 20 annuum var. glabriusculum, Capsicum frutescens [pepper], Capsicum annuum [paprika], Nicotiana tabacum, Nicotiana alata, Nicotiana attenuata, Nicotiana glauca, Nicotiana langsdorffii, Nicotiana obtusifolia, Nicotiana quadrivalvis, Nicotiana repanda, Nicotiana rus tica, Nicotiana sylvestris [tobacco], Solanum tuberosum [potato], Solanum melongena [egg plant], Lycopersicon esculentum, Lycopersicon lycopersicum, Lycopersicon pyriforme, So 25 lanum integrifolium or Solanum lycopersicum [tomato], Sterculiaceae, such as the genus Theobroma, for example the genus and species Theobroma cacao [cacao] or Theaceae, such as the genus Camellia, for example the genus and species Camellia sinensis [tea]. In particular preferred plants to be used as transgenic plants in accordance with the present invention are oil fruit crops which comprise large amounts of lipid compounds, such as pea 30 nut, oilseed rape, canola, sunflower, safflower, poppy, mustard, hemp, castor-oil plant, olive, sesame, Calendula, Punica, evening primrose, mullein, thistle, wild roses, hazelnut, almond, macadamia, avocado, bay, pumpkin/squash, linseed, soybean, pistachios, borage, trees (oil palm, coconut, walnut) or crops such as maize, wheat, rye, oats, triticale, rice, bar ley, cotton, cassava, pepper, Tagetes, Solanaceae plants such as potato, tobacco, eggplant 35 and tomato, Vicia species, pea, alfalfa or bushy plants (coffee, cacao, tea), Salix species, and perennial grasses and fodder crops. Preferred plants according to the invention are oil crop plants such as peanut, oilseed rape, canola, sunflower, safflower, poppy, mustard, hemp, castor-oil plant, olive, Calendula, Punica, evening primrose, pumpkin/squash, lin seed, soybean, borage, trees (oil palm, coconut). Especially preferred plants are plants 4195554_1 (GHMattes) P92082.AU.1 such as sunflower, safflower, tobacco, mullein, sesame, cotton, pumpkin/squash, poppy, evening primrose, walnut, linseed, hemp, thistle or safflower. Very especially preferred plants are plants such as safflower, sunflower, poppy, evening primrose, walnut, linseed, or hemp. 5 Preferred mosses are Physcomitrella or Ceratodon. Preferred algae are Isochrysis, Man toniella, Ostreococcus or Crypthecodinium, and algae/diatoms such as Phaeodactylum or Thraustochytrium. More preferably, said algae or mosses are selected from the group con sisting of: Shewanella, Physcomitrella, Thraustochytrium, Nannochloropsis, Fusarium, Phy 10 tophthora, Ceratodon, Isochrysis, Aleurita, Muscarioides, Mortierella, Phaeodactylum, Cry phthecodinium, specifically from the genera and species Thallasiosira pseudonona, Eu glena gracilis, Physcomitrella patens, Phytophtora infestans, Fusarium graminaeum, Cryptocodinium cohnii, Ceratodon purpureus, Isochrysis galbana, Aleurita farinosa, Thraus tochytrium sp., Nannochloropsis oculata, Muscarioides viallii, Mortierella alpina, Phaeodac 15 tylum tricornutum or Caenorhabditis elegans or especially advantageously Phytophtora in festans and Cryptocodinium cohnii. Transgenic plants may be obtained by transformation techniques as elsewhere in this specification. Preferably, transgenic plants can be obtained by T-DNA-mediated transforma 20 tion. Such vector systems are, as a rule, characterized in that they contain at least the vir genes, which are required for the Agrobacterium-mediated transformation, and the se quences which delimit the T-DNA (T-DNA border). Suitable vectors are described else where in the specification in detail. 25 Also encompassed are transgenic non-human animals comprising the vector or polynucleo tide of the present invention. Preferred non-human transgenic animals envisaged by the present invention are fish, such as herring, salmon, sardine, redfish, eel, carp, trout, halibut, mackerel, zander or tuna. 30 It will be understood that in order to produce the LCPUFA according to the invention, the C16- or C18- fatty acids must first be desaturated by the enzymatic activity of a desaturase and subsequently be elongated by at least two carbon atoms via an elongase in the non human transgenic organism. After one elongation cycle, this enzyme activity gives C18- or C20-fatty acids and after two or three elongation cycles C22- or C24-fatty acids. The activity 35 of the desaturases and elongases used in the process according to the invention preferably leads to C18-, C20-, C22- and/or C24-fatty acids, advantageously with at least two double bonds in the fatty acid molecule, preferably with three, four or five double bonds, especially preferably to give C20- and/or C22-fatty acids with at least two double bonds in the fatty acid molecule, preferably with three, four or five double bonds in the molecule. After a first 4195554_1 (GHMattes) P92082.AU.1 desaturation and the elongation have taken place, further desaturation steps such as, for example, one in the delta-5 position may take place. Products of the process according to the invention which are especially preferred are DGLA, ARA, EPA DPA and/or DHA, most preferably EPA and/or DHA. Desaturases and elongases which are required for this proc 5 ess may not always be present naturally in the organism. Accordingly, the present inven tion, preferably, envisages a transgenic non-human organism which in addition to the polynucleotide of the present invention comprises polynucleotides encoding such desatu rases and/or elongases as required depending on the selected organism. Preferred desatu rases and/or elongases which shall be present in the organism are at least one enzyme 10 selected from the group consisting of: A-4-desaturase, A-5-desaturase, A-5-elongase, A-6 desaturase, A12-desaturase, A15-desaturase, (o3-desaturase and A-6-elongase. Especially prefered are the bifunctional d12d15-Desaturases dl2dl5Des(Ac) from Acanthamoeba castellanii (W02007042510), dl2dl5Des(Cp) from Claviceps purpurea (W02008006202) and dl2dl5Des(Lg)l from Lottia gigantea (W02009016202), the d12-Desaturases 15 d12Des(Co) from Calendula officinalis (W0200185968), d12Des(Lb) from Laccaria bicolor (W02009016202), d12Des(Mb) from Monosiga brevicollis (W02009016202), d12Des(Mg) from Mycosphaerella graminicola (W02009016202), dl2Des(Nh) from Nectria haemato cocca (W02009016202), d12Des(Ol) from Ostreococcus lucimarinus (W02008040787), d12Des(Pb) from Phycomyces blakesleeanus (W02009016202), d12Des(Ps) from Phy 20 tophthora sojae (W02006100241) and d12Des(Tp) from Thalassiosira pseudonana (W02006069710), the d15-Desaturases d15Des(Hr) from Helobdella robusta (W02009016202), d15Des(Mc) from Microcoleus chthonoplastes (W02009016202), d15Des(Mf) from Mycosphaerella fijiensis (W02009016202), d15Des(Mg) from Mycosphae rella graminicola (W02009016202) and dl5Des(Nh)2 from Nectria haematococca 25 (W02009016202), the d4-Desaturases d4Des(Eg) from Euglena gracilis (W02004090123), d4Des(Tc) from Thraustochytrium sp. (W02002026946) and d4Des(Tp) from Thalassiosira pseudonana (W02006069710), the d5-Desaturases d5Des(OI)2 from Ostreococcus lucima rinus (W02008040787), d5Des(Pp) from Physcomitrella patens (W02004057001), d5Des(Pt) from Phaeodactylum tricornutum (W02002057465), d5Des(Tc) from Thrausto 30 chytrium sp. (W02002026946), d5Des(Tp) from Thalassiosira pseudonana (W02006069710) and the d6-Desaturases d6Des(Cp) from Ceratodon purpureus (W02000075341), d6Des(Ol) from Ostreococcus lucimarinus (W02008040787), d6Des(Ot) from Ostreococcus tauri (W02006069710), d6Des(Pf) from Primula farinosa (W02003072784), d6Des(Pir)_BO from Pythium irregulare (W02002026946), d6Des(Pir) 35 from Pythium irregulare (W02002026946), d6Des(Plu) from Primula luteola (W02003072784), d6Des(Pp) from Physcomitrella patens (W0200102591), d6Des(Pt) from Phaeodactylum tricornutum (W02002057465), d6Des(Pv) from Primula vialii (W02003072784) and d6Des(Tp) from Thalassiosira pseudonana (W02006069710), the d8-Desaturases d8Des(Ac) from Acanthamoeba castellanii (EP1790731), d8Des(Eg) from 4195554_1 (GHMattes) P92082.AU.1 Euglena gracilis (W0200034439) and d8Des(Pm) from Perkinsus marinus (W02007093776), the o3-Desaturases o3Des(Pi) from Phytophthora infestans (W02005083053), o3Des(Pir) from Pythium irregulare (W02008022963), o3Des(Pir)2 from Pythium irregulare (W02008022963) and o3Des(Ps) from Phytophthora sojae 5 (W02006100241), the bifunctional d5d6-elongases d5d6EIo(Om)2 from Oncorhynchus my kiss (W02005012316), d5d6Elo(Ta) from Thraustochytrium aureum (W02005012316) and d5d6Elo(Tc) from Thraustochytrium sp. (W02005012316), the d5-elongases d5Elo(At) from Arabidopsis thaliana (W02005012316), d5Elo(At)2 from Arabidopsis thaliana (W02005012316), d5EIo(Ci) from Ciona intestinalis (W02005012316), d5Elo(Ol) from Os 10 treococcus lucimarinus (W02008040787), d5Elo(Ot) from Ostreococcus tauri (W02005012316), d5EIo(Tp) from Thalassiosira pseudonana (W02005012316) and d5Elo(XI) from Xenopus laevis (W02005012316), the d6-elongases d6Elo(Ol) from Ostreo coccus lucimarinus (W02008040787), d6Elo(Ot) from Ostreococcus tauri (W02005012316), d6Elo(Pi) from Phytophthora infestans (W02003064638), d6Elo(Pir) 15 from Pythium irregulare (W02009016208), d6Elo(Pp) from Physcomitrella patens (W02001059128), d6EIo(Ps) from Phytophthora sojae (W02006100241), d6Elo(Ps)2 from Phytophthora sojae (W02006100241), d6EIo(Ps)3 from Phytophthora sojae (W02006100241), d6EIo(Pt) from Phaeodactylum tricornutum (W02005012316), d6EIo(Tc) from Thraustochytrium sp. (W02005012316) and d6Elo(Tp) from Thalassiosira pseudona 20 na (W02005012316), the d9-elongases d9Elo(Ig) from Isochrysis galbana (W02002077213), d9Elo(Pm) from Perkinsus marinus (W02007093776) and d9Elo(Ro) from Rhizopus oryzae (W02009016208). Furthermore, the present invention encompasses a method for the manufacture of polyun 25 saturated fatty acids comprising: a) cultivating the host cell of the invention under conditions which allow for the production of polyunsaturated fatty acids in said host cell; and b) obtaining said polyunsaturated fatty acids from the said host cell. 30 The term "polyunsaturated fatty acids (PUFA)" as used herein refers to fatty acids compris ing at least two, preferably, three, four, five or six, double bonds. Moreover, it is to be un derstood that such fatty acids comprise, preferably from 18 to 24 carbon atoms in the fatty acid chain. More preferably, the term polyunsaturated fatty acids relates to long chain PUFA (LCPUFA) having from 20 to 24 carbon atoms in the fatty acid chain. Preferred unsaturated 35 fatty acids in the sense of the present invention are selected from the group consisting of arachidonic acid (ARA) 20:4 (5,8,11,14), eicosapentaenoic acid (EPA) 20:5 (5,8,11,14,17), and docosahexaenoic acid (DHA) 22:6 (4,7,10,13,16,19) and, more preferably, from EPA and DHA. Thus, it will be understood that most preferably, the methods provided by the present invention relating to the manufacture of EPA or DHA. Moreover, also encompassed 4195554_1 (GHMattes) P92082.AU.1 are the intermediates of LCPUFA which occur during synthesis starting from oleic acid 18:1 (9), preferably, linoleic acid 18:2 (9,12), alpha-linolenic acid 18:3 (9,12,15), gamma-linolenic acid 18:3 (6,9,12), stearidonic acid 18:4 (6,9,12,15), dihomo-gamma-linoleic acid 20:3 (8,11,14), eicosadienoic acid 20:2 (11,14), eicosatrienoic acid 20:3 (11,14,17), eicosate 5 traenoic acid 20:4 (8,11,14,17) and docospentaenoic acid (DPA) 22:5 (4,7,10,13,16). The term "cultivating" as used herein refers maintaining and growing the host cells under culture conditions which allow the cells to produce the said polyunsaturated fatty acid, i.e. the PUFA and/or LCPUFA referred to above, preferably, as triglyceride esters. This implies 10 that the polynucleotide of the present invention is expressed in the host cell so that the acyl transferase activity is present. Suitable culture conditions for cultivating the host cell are described in more detail below. The term "obtaining" as used herein encompasses the provision of the cell culture including 15 the host cells and the culture medium as well as the provision of purified or partially purified preparations thereof comprising the polyunsaturated fatty acids, preferably, as triglyceride esters. More preferably, the PUFA and LCPUFA are to be obtained as triglyceride esters, e.g., in form of an oil. More details on purification techniques can be found elsewhere herein below. 20 The host cells to be used in the method of the invention are grown or cultured in the manner with which the skilled artisan is familiar, depending on the host organism. Usually, host cells are grown in a liquid medium comprising a carbon source, usually in the form of sugars, a nitrogen source, usually in the form of organic nitrogen sources such as yeast extract or 25 salts such as ammonium sulfate, trace elements such as salts of iron, manganese and magnesium and, if appropriate, vitamins, at temperatures of between 00C and 1000C, pref erably between 100C and 600C under oxygen or anaerobic atmosphere depedent on the type of organism. The pH of the liquid medium can either be kept constant, that is to say regulated during the culturing period, or not. The cultures can be grown batchwise, semi 30 batchwise or continuously. Nutrients can be provided at the beginning of the fermentation or administerd semicontinuously or continuously: The produced PUFA or LCPUFA can be iso lated from the host cells as described above by processes known to the skilled artisan, e.g., by extraction, distillation, crystallization, if appropriate precipitation with salt, and/or chroma tography. It might be required to disrupt the host cells prior to purification. To this end, the 35 host cells can be disrupted beforehand. The culture medium to be used must suitably meet the requirements of the host cells in question. Descriptions of culture media for various mi croorganisms which can be used as host cells according to the present invention can be found in the textbook "Manual of Methods for General Bacteriology" of the American Soci ety for Bacteriology (Washington D.C., USA, 1981). Culture media can also be obtained 4195554_1 (GHMattes) P92082.AU.1 from various commercial suppliers. All media components are sterilized, either by heat or by filter sterilization. All media components may be present at the start of the cultivation or added continuously or batchwise, as desired. If the polynucleotide or vector of the invention which has been introduced in the host cell further comprises an expressible selection 5 marker, such as an antibiotic resistance gene, it might be necessary to add a selection agent to the culture, such as an antibiotic in order to maintain the stability of the introduced polynucleotide. The culture is continued until formation of the desired product is at a maxi mum. This is normally achieved within 10 to 160 hours. The fermentation broths can be used directly or can be processed further. The biomass may, according to requirement, be 10 removed completely or partially from the fermentation broth by separation methods such as, for example, centrifugation, filtration, decanting or a combination of these methods or be left completely in said broth. The fatty acid preparations obtained by the method of the inven tion, e.g., oils, comprising the desired PUFA or LCPUFA as triglyceride esters are also suit able as starting material for the chemical synthesis of further products of interest. For ex 15 ample, they can be used in combination with one another or alone for the preparation of pharmaceutical or cosmetic compositions, foodstuffs, or animal feeds. Chemically pure triglycerides comprising the desired PUFA or LCPUFA can also be manufactured by the methods described above. To this end, the fatty acid preparations are further purified by extraction, distillation, crystallization, chromatography or combinations of these methods. In 20 order to release the fatty acid moieties from the triglycerides, hydrolysis may be also re quired. The said chemically pure triglycerides or free fatty acids are, in particular, suitable for applications in the food industry or for cosmetic and pharmacological compositions. Moreover, the present invention relates to a method for the manufacture of poly 25 unsaturated fatty acids comprising: a) cultivating the non-human transgenic organism of the invention under conditions which allow for the production of polyunsaturated fatty acids in said host cell; and b) obtaining said polyunsaturated fatty acids from the said non-human transgenic organ ism. 30 Further, it follows from the above that a method for the manufacture of an oil, lipid or fatty acid composition is also envisaged by the present invention comprising the steps of any one of the aforementioned methods and the further step of formulating PUFA or LCPUFA as oil, lipid or fatty acid composition. Preferably, said oil, lipid or fatty acid composition is to 35 be used for feed, foodstuffs, cosmetics or pharmaceuticals. Accordingly, the formulation of the PUFA or LCPUFA shall be carried out according to the GMP standards for the individual envisaged products. For example, oil may be obtained from plant seeds by an oil mill. How ever, for product safety reasons, sterilization may be required under the applicable GMP standard. Similar standards will apply for lipid or fatty acid compositions to be applied in 4195554_1 (GHMattes) P92082.AU.1 cosmetic or pharmaceutical compositions. All these measures for formulating oil, lipid or fatty acid compositions as products are comprised by the aforementioned manufacture. The present invention also relates to oil comprising a polyunsaturated fatty acid or a poly 5 unsaturated fatty acid composition obtainable by the aforementioned methods. The term "oil" refers to a fatty acid mixture comprising unsaturated and/or saturated fatty acids which are esterified to triglycerides. Preferably, the triglycerides in the oil of the inven tion comprise PUFA or LCPUFA as referred to above. The amount of esterified PUFA 0 and/or LCPUFA is, preferably, approximately 30%, a content of 50% is more preferred, a content of 60%, 70%, 80% or more is even more preferred. The oil may further comprise free fatty acids, preferably, the PUFA and LCPUFA referred to above. For the analysis, the fatty acid content can be, e.g., determined by GC analysis after converting the fatty acids into the methyl esters by transesterification. The content of the various fatty acids in the oil 5 or fat can vary, in particular depending on the source. The oil, however, shall have a non naturally occurring composition with respect to the PUFA and/or LCPUFA composition and content. It will be understood that such a unique oil composition and the unique esterifica tion pattern of PUFA and LCPUFA in the triglycerides of the oil shall only be obtainable by applying the methods of the present invention specified above. Moreover, the oil of the in .0 vention may comprise other molecular species as well. Specifically, it may comprise minor impurities of the polynucleotide or vector of the invention. Such impurities, however, can be detected only by highly sensitive techniques such as PCR. The present invention further provides a nucleic acid construct comprising a polynucleotide, .5 wherein the polynucleotide comprises a nucleic acid sequence elected from the group con sisting of: a) a nucleic acid sequence having a nucleotide sequence as shown in any one of SEQ ID NOs: 52 and 54; b) a nucleic acid sequence encoding a polypeptide having an amino acid sequence as 30 shown in SEQ ID NO: 53, c) a nucleic acid sequence being at least 60% identical to the nucleic acid sequence of a). The present invention further provides a vector comprising the nucleic acid construct as 35 described herein. The present invention further provides a transgenic host cell comprising the nucleic acid construct as described herein or the vector as described herein. 7065178_1 (GHMatters) P92082.AU.1 The present invention further provides a method for the manufacture of a polypeptide en coded by a nucleic acid construct as described herein comprising a) cultivating the host cell as described herein under conditions which allow for the pro 5 duction of the said polypeptide; and b) obtaining the polypeptide from the host cell of step a). The present invention further provides a polypeptide encoded by the nucleic acid construct as described herein or which is obtained by the method as described herein. 0 The present invention further provides a non-human transgenic organism comprising the nucleic acid construct as described herein or the vector as described herein. The present invention further provides a feed, feedstuff, cosmetic or pharmaceutical com 5 prising the oil, lipid or fatty acid composition as described herein. The contents of all references cited throughout this application are herewith incorporated by reference in general and with respect to their specific disclosure content referred to above. .0 This invention is further illustrated by the following figures and examples which should not be construed as limiting the scope of the invention. FIGURES .5 Figure 1: Cloning strategy employed for stepwise buildup of plant expression plasmids of the invention. Figure 2: Vector map of the bbc construct used for Arabidopsis transformation. 30 Figure 3: GC chromatogram of fatty acids methyl esters of total fatty acids of Col-O, fael mutant and fae Itransformed with bbc. Total fatty acids were measured as descibed by Wu et al., 2005. The content of the different fatty is indicated in table 5. 7065178_1 (GHMatters) P92082.AU.1 Figure 4: Total ion count of 26 acyl CoA ESI-MS/MS MRM pairs for Arabidopsis (A) Col-0 and (B) fael harbouring EPA biosynthesis pathway. Maturing Arabidopsis seeds were har vested 18 days after flowering. Acyl-CoA was extracted according to Larson et al (2001) 5 and LC conditions after Han et al. (2010). Figure 5: Identification of Eicosapentaenoic and Arachidonic-CoA's in the acyl CoA pool of Arabidopsis Col-0 and EPA producing plants. MRM chromatograms of co-eluting acyl-CoA of interest in (A) wild type and (C) fael harbouring EPA biosynthetic pathway with recorded 10 reactions shown for each transition, isotopic peaks (IP) of homologous long chain acyl CoA are shown. (B) Characteristic fragmentation of the protonated acyl-CoA by neutral loss of 507 to give the protonated acyl pantetheine group. Figure 6: LPCAT activity assay. 15 A yeast mutant lacking LPEAT and LPCAT activity (due to knockout of the gene YOR175c) was transformed with the empty vector pYES2.1 (lane marked "-") and with pYES2.1 har boring the cDNA of pLPAAT-c6316(No) (lane 1 and 2, SEQ-ID: 13). Microsomal isolations of these transformants and the wildtype yeast strain BY4742 (lane marked "+") containing 5pg protein where incubated with alpha-linolenic acid-CoA and [14C]-18:1 20 lysophosphatidylcholine (LPC). Thin layer chromatography was performed to separate lipid classes. Like for wildtype yeast (lane marked "+"), phosphatidylcholine (PC) is observed for both yeast clones shown in lane 1 and 2, indicating the gene pLPAAT c6316(No) has LPCAT activity and complements the missing LPCAT activity of the knockout strain. 25 Figure 7: LPAAT activity assay. A yeast mutant lacking LPAAT activity (due to knockout of the gene YDL052c) was trans formed with the empty vector pYES2.1 (lane marked "-") and with pYES2.1 harboring the cDNA of pLPAAT-c6316(No) (lane 1 and 2, SEQ-ID: 13). Microsomal isolations of these transformants and the wildtype yeast strain BY4742 (lane marked "+") containing 5pg pro 30 tein where incubated with alpha-linolenic acid-CoA and [ 14 C]-18:1-lysophosphatidic acid (LPA). Thin layer chromatography was performed to separate lipid classes. Like for wild type yeast (lane marked "+"), phosphatidic acid (PA) is observed for both yeast clones shown in lane 1 and 2, indicating the gene pLPAAT-c6316(No) has LPAAT activity and complements the missing LPAAT activity of the knockout strain. 35 Figure 8: DGAT activity assay. A yeast mutant lacking the capability to synthesis TAG (due to knockout of the four genes YCR048W, YNR019W, YOR245C and YNR008W) was transformed with the empty vector pYES2.1 (lane marked "-") and with pYES2.1 harboring the cDNA of pDGAT2 4195554_1 (GHMattes) P92082.AU.1 c19425mod(Ta) (SEQ-ID 52, lane 1 and 2), pDGAT2_c4648(No) (SEQ-ID 34, lane 5 and 6), pDGAT2_c48271(No) (SEQ-ID 102, lane 7 and 8), BnDGAT1 (SEQ-ID 107, lane 9 and 10), AtDGAT1 (SEQ-ID 105, lane 11 and 12), pDGAT2_c699(No) (SEQ-ID 19, lane 13 and 14) and pDGAT2_c2959(No) (SEQ-ID 25, lane 15). Microsomal isolations of these transfor 5 mants and the wildtype yeast strain G175 (lane marked "+") where incubated with 14C labled oleic acid and diacylglyerole (DAG). Thin layer chromatography was performed to separate lipid classes. Like for wildtype yeast (lane marked "+"), triacylglycerole (TAG) is observed in lane 1, 2, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 and 15, indicating pDGAT2 c19425mod(Ta), pDGAT2_c4648(No), pDGAT2_c48271(No), BnDGAT1, AtDGAT1, 10 pDGAT2_c699(No) and pDGAT2_c2959(No) encode polypeptides having DGAT activity and complement the missing TAG-synthesis capability of the knockout. Figure 9: Substrate specificity of AtDGAT1 and BnDGAT1. The specific activity of the en zymes AtDGAT1 and BnDGAT1 using the substrates indicated at the x-axis is given as the 15 amount (in nmol) of substrate consumed in one minute per mg total protein and was deter mined as described in example 10. Figure 10: Substrate specificity of pDGAT2-c19425(Ta) compared to AtDGAT1 and BnDGAT1. The specific activity of the enzymes pDGAT2-c19425(Ta), AtDGAT1 and 20 BnDGAT1 using the substrates indicated at the x-axis is given as the amount (in nmol) of substrate consumed in one minute per mg total protein and was determined as described in example 10. Figure 11: Substrate specificity of pDGAT2_c699(No) and pDGAT2_c4648(No) compared 25 to AtDGAT1 and BnDGAT1. The specific activity of the enzymes pDGAT2_c699(No) and pDGAT2_c4648(No), AtDGAT1 and BnDGAT1 using the substrates indicated at the x-axis is given as the amount (in nmol) of substrate consumed in one minute per mg total protein and was determined as described in example 10. 30 EXAMPLES Example 1: General cloning methods Cloning methods as e.g. use of restriction endonucleases to cut double stranded DNA at 35 specific sites, agarose gel electrophoreses, purification of DNA fragments, transfer of nucle ic aicds onto nitrocellulose and nylon memebranes, joining of DNA-fragments, transforma tion of E.coli cells and culture of bacteria where perforemed as described in Sambrook et al. (1989) (Cold Spring Harbor Laboratory Press: ISBN 0-87965-309-6). 4195554_1 (GHMattes) P92082.AU.1 Example 2: Sequence Analysis of recombinant DNA Sequencing of recombinant DNA-molecules was performed using a laser-fluorescence DNA sequencer (Applied Biosystems Inc, USA) employing the sanger method (Sanger et al. 5 (1977) Proc. NatI. Acad. Sci. USA 74, 5463-5467). Expression constructs harboring frag ments obtained by polymerase chain reactions were subjected to sequencing to confirm the correctness of expression cassettes consisting of promoter, nulceic acid molecule to be expressed and terminator to avoid mutations that might result from handling of the DNA during cloning, e.g. due to incorrect primers, mutations from exposure to UV-light or errors 10 of polymerases. Example 3: Cloning of yeast expression construct via homologous recombination The open reading frame listed in SEQ ID NOs: 52, 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 15 37, 40, 43, 46, 49, 55, 102, 105 and 107 encoding polypeptides with the amino acid se quence SEQ ID NOs: 53, 2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, 38, 41, 44, 47, 50, 56 ,103, 106 and 108 that have acyltransferase activity can amplified using the primer listed in table 2 in a polymerase chain reaction. By doing so, the open reading frame is 5' fused to about 60 nucleotides of the 3' end of the GAL1 promotor sequence with simultanious intro 20 duction of and Asc I and/or Nco I restriction site between the fusion site and 3' fused to about 60 nucleotides of the 5' end of the CYC1 terminator sequence with simultanious in troduction of and Pac I restriction site. To integrate these fragments into pYES2.1 TOPO downstream of the galactose inducible GAL1 Promotor via homologous recombination, the vector pYES2.1 (Invitrogen) can be digested using the restriction endonucleases Pvull and 25 Xba I, and Saccharomyces cerevisea can be transformed with 5 to 20ng of linearized pYES2.1 TOPO vector and 20 to 100ng PCR product per 50 pl competent cells using the transformation method described by Schiestl et al. (Schiestl et al. (1989) Curr. Genet. 16(5 6), pp. 339-346), to obtain pYES-pLPLATc1216(No), pYES-pLPLAT_c3052(No), pYES pLPEAT-c7109(Ta), pYES-pLPAAT-c2283(No), pYES-pLPAAT-c6316(No), pYES 30 pDGAT2_Irc24907(No), pYES-pDGAT2_c699(No), pYES-pDGAT2_c1910(No), pYES pDGAT2_c2959(No), pYES-pDGAT2_c4857(No), pYES-pDGAT1_c21701(No), pYES pDGAT2_c4648(No), pYES-pDGAT2_c1660(No), pYES-pDGAT2_c29432(No), pYES pDGAT2_c1052(No), pYES-pDGAT2-c18182(Ta), pYES-pDGAT2-c5568(Ta), pYES pDGAT2-c19425(Ta), pYES-pDGAT2_c48271(No), AtDGAT1, BnDGAT1 and pYES 35 pGPATc813(No) in various wildtype yeasts and yeast mutants. Positive transformants can be selected based on the complementation of the URA auxotrophy of the chosen S.cerevisia strain. To validate the correctness of the expression construct harbored by a particular yeast clone, plasmids can be isolated as described in Current Protocols in Mole cular Biology (Hoffmann, Curr. Protoc. Mol. Biol. 2001 May; Chapter 13:Unitl3.11), trans 4195554_1 (GHMattes) P92082.AU.1 formed into E.coli for amplification and subjected to sequencing of the expression cassette as described in example 2. For later cloning into plant expression plasmids, the introduced restrictions site for Asc I and/or Nco I in combination with Pac I can be used. 5 Table 2: Primer sequences for cloning acyltransferase-polynucleotides of the invention for yeast expression Gene-Name Primer SEQ-ID Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatggacaa ggcactggcaccgtt 46 pLPLAT~c1216(No) Rvre Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaactaaactttcttccttccc tcta 47 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatgaccacg actgtcatctctag 48 pLPLAT~c3052(No) Rvre Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaatcaaagcctcccgcac aacgagc 49 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatggaggg catcgagtcgatagt 50 pLPEAT-c71 09(Ta) Rvre Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaactataaggcttctcccg gcgcgg 51 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatgaagac pLPAAT-c2283(No) gcccacgagcctggc 52 Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaattaagctctcgaatcgtc cttct 53 4195554_1 (GHMattes) P92082.AU.1 Gene-Name Primer SEQ-ID Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatggtcagg pLPAAT-c6316(No) aggaagatggacgt 54 Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaatcacgacgccggcgc cttgcagt 55 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatggcaccc pDGAT2_Irc24907(N tccccaccggcccc 56 a) Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaatcatttgaccactaaggt ggcct 57 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatgggtctat pDGAT2_c699(No) ttggcagcgggat 58 Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaactaaaagaaattcaac gtccgat 59 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatgttgagta pDGAT2_c1910(No) tccccgagtcgtc 60 Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaactaaaagaaatccagc tccctgt 61 Forward: pDGAT2_c2959(No) ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatgacgccg caagccgatatcac 62 4195554_1 (GHMattes) P92082.AU.1 Gene-Name Primer SEQ-ID Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaattactcaatggacaacg ggcgcg 63 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatggcttacc tcttccgtcgtcg 64 pDGAT2_c4857(No) Rvre Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaattaggcgatcgcaatg aactcct 65 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatgccttttg pDGAT1_c21701(No) gacgggctgcatc 66 Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaatcacccgaaaatatcct ccttct 67 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatggccaa pDGAT2_c4648(No) ggctaacttcccgcc 68 Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaatcactttataagcagctt cttgt 69 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatgttgttgc pDGAT2_c1660(No) agggattaagctg 70 Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaatcacaacaggaccaat ttatgat 71 4195554_1 (GHMattes) P92082.AU.1 Gene-Name Primer SEQ-ID Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatgttgatgg pDGAT2_c29432(No) cgccgtcgcggcg 72 Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaatcagacgatgcgaagc gtcttgt 73 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatgggcgct pDGAT2_c1052(No) accactgcgaccca 74 Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaatcacgacttcggacagt ccaaaa 75 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatgtcgttcg pDGAT2-c18182(Ta) ttgagcacagcgc 76 Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaactacacaaatcgcatc gtcttgt 77 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatggtcttcct ctgccttcccta 78 pDGAT2-c5568(Ta) Reverse: Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaactacgagtccagccac ttgatgc 79 Forward: pDGAT2-c19425(Ta) ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatgtttcttcg catcgaacggga 80 4195554_1 (GHMattes) P92082.AU.1 Gene-Name Primer SEQ-ID Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaactaaccctcggtgtaca gcgccg 81 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatgccatcc cgcagcaccattga 82 pGPAT~c813(No) Rvre Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaatcagacaagctcctctt ccccct 83 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatggccgcc pDGAT2_c48271(No) atctcaccgcgcaa 109 Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaactaccacacctccaact tcgccc 110 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatggcgattt AtDGAT1 tggattctgctgg 111 Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaatcatgacatcgatcctttt cggt 112 Forward: ataaaagtatcaacaaaaaattgttaatatacctctatactttaacgt caaggagaaaaaaccccggatcggcgcgccaccatggagattt BnDGAT1 tggattctggagg 113 Reverse: aactataaaaaaataaatagggacctagacttcaggttgtctaact ccttccttttcggttagagcggatttaattaactatgacatctttcctttg cggt 114 Table 3: Coding polynucleotide sequences, amino acid sequences encoded thereby and 4195554_1 (GHMattes) P92082.AU.1 expressed sequences (mRNA) of the acyltransferases of the invention Amin SEQ- SEQ ORF SEQ- o ID mRNA ID Gene name Organism in bp ID No. acids No. in bp No. pLPLAT-c1216(No Nannochlorops is oculata 1485 1 494 2 1908 3 pLPLAT-c3052(No Nannochlorops is oculata 1776 4 591 5 2247 6 Thraustochytri pLPEAT-c7109(Ta) um aureum 1134 7 377 8 1288 9 pLPAAT-c2283(No Nannochlorops is oculata 1284 10 427 11 1826 12 pLPAAT-c6316(No Nannochlorops is oculata 1395 13 464 14 1771 15 pDGAT2_Irc24907( Nannochlorops No) is oculata 1026 16 341 17 1100 18 Nannochlorops pDGAT2_c699(No) is oculata 1206 19 401 20 1772 21 pDGAT2_c191O(N Nannochlorops o) is oculata 1173 22 390 23 1239 24 pDGAT2_c2959(N Nannochlorops o) is oculata 1089 25 362 26 1609 27 pDGAT2_c4857(N Nannochlorops o) is oculata 1464 28 487 29 1682 30 pDGATlc21701( Nannochlorops No) is oculata 1539 31 512 32 1904 33 pDGAT2_c4648(N Nannochlorops o) is oculata 1083 34 360 35 1362 36 pDGAT2_c1660(N Nannochlorops o) is oculata 1695 37 564 38 2074 39 pDGAT2_c29432( Nannochlorops No) is oculata 1029 40 342 41 1585 42 pDGAT2_c1O52(N Nannochlorops o) is oculata 1251 43 416 44 1923 45 pDGAT2- Thraustochytri c18182(Ta) um aureum 930 46 309 47 1134 48 pDGAT2- Thraustochytri c5568(Ta) um aureum 1179 49 392 50 1303 51 4195554_1 (GHMattes) P92082.AU.1 pDGAT2- Thraustochytri c19425(Ta) um aureum 1389 52 462 53 1547 54 Nannochlorops pGPAT_c813(No) is oculata 1977 55 658 56 2460 57 pDGAT2_c48271( Nannochlorops No) is oculata 960 102 319 103 1265 104 Example 4: Assembly of genes required for PUFA synthesis within a T-plasmid For synthesis of EPA in Arabidopsis seeds, the set of genes encoding the proteins of the 5 metabolic EPA pathway (table 4) was combined with expression elements (promoter, termi nators) and transferred into binary t-plasmids that were used for agrobacteria mediated transformation of plants as described in example 5. To this end, the general cloning strate gy depicted in figure 1 was employed: Genes listed in table 4 were PCR-amplified using Phusion T M High-Fidelity DNA Polymerase (NEB, Frankfurt, Germany) according to the 10 manufactures instructions from cDNA using primer introducing a Nco I and/or Asc I restric tion site at the 5' terminus, and a PacI restriction site at the 3' terminus (figure 1B). To ob tain the final expression modules, PCR-amplified genes were cloned between promoter and terminator via Nco I and/or Pac I restriction sites (figure 1C). Up to three of those expres sion modules were combined as desired to expression cassettes harbored by either one of 15 pENTR/A, pENTR/B or pENTR/C (figure 1D).. Finally, the Multisite Gateway TM System (In vitrogen) was used to combine three expression cassette harbored by pENTR/A, pENTR/B and pENTR/C (figure 1E) to obtain the final binary T-plasmids bbc (SEQ-ID 101, figure 2). Table 4: Genes of the bbc construct for synthesis of EPA (20:5n-3) in Arabidopsis seeds. 20 The elements controlling the expression of the respective genes are as well indicated. Name Source Organism Activity SEQ- Promoter Terminator ID d12Des(Ps) Phytophtora sojae d-12 Desaturase 96 p-BnNapin t-E9 d6Des(Ot) Ostreococcus tauri d-6 Desaturase 97 p-SBP t-CatpA d5Des(Tc) Traustochytrium ssp. d-5 Desaturase 98 p-LuCnl t-AgroOCS d6Elo(Pp) Physcomitrellapatens d-6 Elongase 99 p-VfUSP t-CaMV35S o-3Des(Pi) Phytophthora o-3 Desaturase 100 p-Napin t-E9 infestans Example 5: Plant Transformation 25 The resulting binary vector bbc harboring the genes reconstituting EPA biosynthesis path 4195554_1 (GHMattes) P92082.AU.1 way were transformed into Agrobacterium tumefaciens (Hofgen and Willmitzer (1988) Nucl. Acids Res. 16: 9877). The transformation of A. thaliana was accomplished by means of the floral-dip method (Clough and Bent (1998) Plant Journal 16: 735-743), this method is known to the skilled person. Wild-type Arabidopsis seeds contain considerable amounts of 5 eicosenoic acid (20:1) (Table 5). Biosynthesis of 20:1 competes for the substrates of the PUFA biosynthesis pathway. This competition was circumvented by transforming bbc into the Arabidopsis fael mutant (James et al., (1995) The Plant Cell 7:309-319). Example 6: Quantification of metabolic fatty Acyl-CoAs in wild-type and EPA producing 10 Arabidopsis seeds The selected transgenic Arabidopsis plants from example 3 were analyzed in respect to PUFA content in seeds. Seeds from wild-type, fael mutant and transgenics harboring the bbc construct were harvested 18 days after flowering. Total fatty acid, representing the fatty acids esterified to CoA, on lipids and as triacyl-glycerides were extracted and analyzed by 15 gas chromatography as described in Wu et al., (2005) Nature Biotechnology 23(8): 1013 1017. In seeds of fael transformed with bbc the EPA accumulation was 12.2 %, the seeds contained small amounts of indermediate or side products: ARA (3.2 %), SDA (0.8 %), GLA (2.6 %) which were not present in wild-type or fael (Fig 3, Table 5). 20 Table 5: Content of fatty acids in seeds of wild-type (Col-0), fael mutant and fael transformed with bbc construct Fatty acid Common name of FA Col-0 fae1 bbc fael 16:0 Palmitic acid 6,2 8,8 6,8 18:0 Stearic acid 3,1 4,1 5,3 18:1 Oleic acid 16,3 27,5 18,9 18:2 Linoleic acid 28,2 39,0 30,8 18:3n6 Gamma-Linolenic acid 0,0 0,0 2,6 18:3n3 Alpha-Linoleic acid 15,6 18,4 11,9 18:4n3 Stearidonic acid 0,0 0,0 0,8 20:1 Eicosenoic acid 22,8 0,4 0,3 20:4n6 Arachidonic acid 0,0 0,0 3,2 20:5n3 Eicosapentaenoic acid 0,0 0,0 12,2 Others 7,8 1,8 7,2 For PUFA biosynthesis the acyl-moiety has to be shuffled between different metabolic 25 pools. For example, the elongation of the acyl chain by two carbon atoms occurs specifically on acyl-CoA (Zank et al., (2002) The Plant Journal 318(3):255-268. The efficency of the transfer of the acyl-residue between the metabolic pools may represent a 4195554_1 (GHMattes) P92082.AU.1 bottleneck for PUFA production in plants. Therefore the accumulation of EPA or intermediates of EPA biosynthesis as CoA species was analyzed by LC/MS 2 . As a control CoA pool of wild-type seeds were as well analyzed. The Acyl-CoA metabolites were extraced from the seed tissue according to Larson and Graham, 2001. LC/MS 2 was applied 5 as described by Magnes et al., 2005. Briefly, CoA were separeted with high resolution by reversed-phase high performance liquid chromatography (HPLC) with a ammonium hydroxide and acetonitrile gradient. The acyl-CoA species were identified and quantified by multireaction monitoring using triple quadrupole mass spectrometry. Only a few methods using mass spectrometry for characterization of long chain acyl-CoA have been published, 10 the majority of which employ negative ionisation mode showing abundant ions. In contrast, positive ionisation has only one abundant ion [M - H]+, furthermore the predominant ion in

MS

2 spectra is the fatty acyl-pantetheine fragment (m/z 507 - Fig 5 B), characteristic of CoA-activated substances. In choosing the acyl-pantetheine of interest in multireaction monitoring mode (MRM) a very sensitive, selective and reproducible method was estab 15 lished. CoA-activated substances can be monitored by scanning for the neutral loss of phosphoadenosine diphosphate. Generally for reliable analysis, all interfering peaks must be chromatographically separated; in the case of EPA and ARA this is not possible (Fig 4 B). However through the use of MRM, incorporating very short dwell times (15 ms), it is possible to follow the individual chromatograms of acyl-CoA of interest and demonstrate the 20 presence of EPA and ARA in the acyl CoA pool (Fig 5 C). According to internal standards the eicosapentaenoyl-CoA was in the range of ... % of the total Co-A pool. In conclusion these results show that PUFA accumulate in the metabolic CoA pool and are not transferred to DAG to be released as TAG into the seed oil. Such a bottleneck may be overcome by the co-expression of an acyltransferase from table 3, having the appropriate 25 substrate specificity. The application of suitable acyltransferase may increase the flux of fatty acid between the metabolic pools and increase the PUFA biosynthesis rate. Example 7: Activity assays using yeast extracts 30 To characterize the functions of the acyltransferase polypeptides of the invention, yeast mutants can be employed that are defective in certain acyltransferase activities. For exam ple, the yeast mutant Y13749 (Genotype: BY4742; Mat alpha; his3A1; leu2A0; lys2A0; ura3A0; YDL052c::kanMX4) lacking LPAAT activity can be transformed with expression constructs harboring candidate polypeptides to check for restoration (complementation) of 35 LPAAT activity, the yeast mutant Y12431 (genotype BY4742; Mat alpha; his3A1; leu2A0; lys2A0; ura3A0; YOR175c::kanMX4) lacking LPLAT activity can be transformed with ex pression constructs harboring candidate polypeptides to check for restoration (complemen tation) of LPLAT activity, the yeast mutant H1246 (genotype MATa leu2-3,112 trpl-1 can1 100 ura3-1 ade2-1 his3-11,15 YOR245::KanMX4 YNR008W::TRP1 YCR048W::HIS3 4195554_1 (GHMattes) P92082.AU.1 YNRO19W::LEU2) lacking the ability to synthesize triacylglycerole can be transformed with expression constructs harboring candidate polypeptides to check for restoration (comple mentation) of the ability to synthesis triacylglycerole. The yeast mutants can for example harbor the expression constructs listed in example 3 employing the transformation method 5 described in example 3. For LPAAT activity assay, clones of the yeast mutant Y13749 harboring pYES pLPAAT-c6316(No) can be grown at 280C in 10ml selective media (SC-URA) with 2% raf finose as carbon source over night. The next day, expression of the acyltransferase poly 10 peptide can be induced by transferring the cells to fresh media containing 2% galactose, for example by inoculating 100 ml of fresh culture to an optical density (measure at 600nm) of OD600=0.1. Cells are harvested after 24h incubation at 280C by centrifugation at 3000 x g for 5 min and resuspended in 1 ml resuspention buffer (25 mM Tris/HCL pH 7.6) and dis rupted using acid washed zirconium bead (200pm average diameter) in a mill (Retsch, 15 Germany) by three minutes agitation at 300rpm. The supernatant is transferred to a fresh tube and centrifuged at 3000 x g for 5 min. The obtained supernatant is the crude extract. Protein content is measured according to Bradford (Bradford, M.M. (1976), Anal. Biochem. Bd. 72, pp. 248-254) with bovine serum albumin as standard. Assay mixtures contain 1 to 50 pg of protein, 10 pl of 100 nM [ 14 C]-18:1-LPA (giving about 2000 dpm/nmol), 10 pl of 50 20 nM 18:1-CoA or 50nM 18:3n-3-CoA in assay buffer (25mM Tris/HCL pH 7.6, 0.5 mg/ml BSA) to give a total volume of 100 pl. Samples are incubated for 10 min at 300C. The as says are terminated by extraction of the lipids into chloroform according to Blight and Dyer (Bligh, E.G. and Dyer, W.J. (1959), Can. J. Biochem. Physiol. 37, pp. 911-917). Lipids are separated on thin layer chromatography (TLC) silica 60 plates (Merck) using chloro 25 form/methanol/acetic acid/water (90:15:10:3), and autoradiographic pictures are taken using an instant imager (Packard). It can be seen by the formation of phosphatidic acid (PA) in figure 7, that pLPAAT-c6316(No) (SEQ-ID 13, lane 1 and 2) encodes a polypetide having LPAAT activity. 30 For LPCAT and LPEAT activity assay, clones of the yeast mutant Y12431 harboring pYES pLPAAT-c6316(No) can be grown at 28 0 C in 10ml selective media (SC-URA) with 2% raffi nose as carbon source over night. The next day, expression of the acyltransferase polypep tide can be induced by transferring the cells to fresh media containing 2% galactose, for example by inoculating 100 ml of fresh culture to an optical density (measure at 600nm) of 35 OD 6 00 =0.1. Cells are harvested after 24h incubation at 28 0 C by centrifugation at 3000 x g for 5 min and resuspendet in 1 ml resuspention buffer (25 mM Tris/HCL pH 7.6) and dis rupted using acid washed zirconium bead (200pm average diameter) in a mill (Retsch, Germany) by three minutes agitation at 300rpm. The supernatant is transferred to a fresh tube and centrifuged at 3000 x g for 5 min. The obtained supernatant is the crude extract. 4195554_1 (GHMattes) P92082.AU.1 Protein content is measured according to Bradford (Bradford, M.M. (1976), Anal. Biochem. Bd. 72, pp. 248-254) with bovine serum albumin as standard. Assay mixtures contain either 1 Op 1 OOnM [ 1 4 C]-LPC (LPCAT activity assay) or 1 Op 1 OOnM [ 14 C]-LPE (LPEAT activity as say), 1 to 50 pg of protein, 10 pl of 50nM 18:1-CoA or 50nM 18:3n-3-CoA in assay buffer 5 (25mM Tris/HCL pH 7.6, 0.5 mg/ml BSA) to give a total volume of 100 pl. Samples are in cubated for 10 min at 300C. The assays are terminated by extraction of the lipids into chlo roform according to Blight and Dyer (Bligh, E.G. and Dyer, W.J. (1959), Can. J. Biochem. Physiol. 37, pp. 911-917). Lipids are separated on thin layer chromatography (TLC) silica 60 plates (Merck) using chloroform/methanol/acetic acid/water (90:15:10:3), and autoradio 10 graphic pictures are taken using an instant imager (Packard). It can be seen by the forma tion of phosphatidylethanolamine (PC) in figure 6, that pLPAATc6316(No) (SEQ-ID 13, lane 1 and 2) encodes a polypeptide having LPCAT activity. For DGAT activity assay, clones of the yeast mutant H1246 harboring either one of pYES 15 pDGAT2_c699(No), pYES-pDGAT2_c2959(No), pYES-pDGAT2_c4648(No), pYES pDGAT2_c48271(No), pYES-pDGAT2-c19425(Ta), pYES-AtDGAT1, or pYES-BnDGAT1 can be grown at 280C in 10ml selective media (SC-URA) with 2% raffinose as carbon source over night. The next day, expression of the acyltransferase polypeptides can be in duced by transferring the cells to fresh media containing 2% galactose, for example by in 20 oculating 100 ml of fresh culture to an optical density (measure at 600nm) of OD 6 0 0 =0.1. Activity as indicated by the formation of TAG (as indicated, the mutant H1246is unable to synthesize TAG) can be measured either by relying on yeast-endogenous substrate-DAG, or by providing substrate in an in vitro assay. For the former type of assay, cells are harvested after reaching stationary phase during in 25 cubation at 280C by centrifugation at 3000 x g for 5 min and resuspendet in 2 ml resuspen tion buffer (phosphate buffered saline (PBS) pH 7.4, see Sambrook et al., "Molecular Clon ing", Cold Spring Harbor Laboratory, 1989). The equivalent of 200 mg cell pellet is taken, the volume adjusted to 210pl using PBS and 790 pl of methanol:chloroform (2:1) are added. Cells are disrupted using acid washed zirconium bead (200pm average diameter) in a mill 30 (Retsch, Germany) by three minutes agitation at 300rpm and lipids are extracted according to Blight and Dyer (Bligh, E.G. and Dyer, W.J. (1959), Can. J. Biochem. Physiol. 37, pp. 911-917). The in vitro assay is the preferred way of testing for DGAT activity, when activity is known or expected to be week when relying on endogenous substrate. Instead, both the type and 35 concentration of the DAG acceptor molecule, as well as the type and concentration of the fatty acid-CoA can be controlled. To do so, cells are harvested after 24h incubation at 28 0 C by centrifugation at 3000 x g for 5 min and resuspendet in 1 ml resuspention buffer (25 mM Tris/HCL pH 7.6) and disrupted using acid washed zirconium bead (200pm average diame ter) in a mill (Retsch, Germany) by three minutes agitation at 300rpm. The supernatant is 4195554_1 (GHMattes) P92082.AU.1 transferred to a fresh tube and centrifuged at 3000 x g for 5 min. The obtained supernatant is the crude extract. Protein content is measured according to Bradford (Bradford, M.M. (1976), Anal. Biochem. Bd. 72, pp. 248-254) with bovine serum albumin as standard. Assay mixtures contain 10 pl 50 nM [ 14 C]-6:0-DAG (giving about 3000 dpm/nmol), 50 pg of micro 5 somal protein (the amount can be adjusted to stay within linear conditions without substrate limitation), 10 pl of 50 nM 18:3n-3-CoA or 50 nM 22:6n-3-CoA in assay buffer (50 mM Hepes buffer pH 7.2, 1 mg/ml BSA) to give a total volume of 100 pl. Samples are incubated for 10 min at 300C. In either case - in vivo or in vitro assay - lipids are separated on thin layer chromatography 10 (TLC) silica 60 plates (Merck) using hexane:diethylether:acetic acid (70:30:1), and stained in iodine vapor. It can be seen by the formation of triacylglycerole (TAG) using the in vitro assay-conditions in figure 8, that pDGAT2-c19425mod(Ta) (SEQ-ID 52, lane 1 and 2), pDGAT2_c4648(No) (SEQ-ID 34, lane 5 and 6), pDGAT2_c48271(No) (SEQ-ID 102, lane 7 and 8), BnDGAT1 (SEQ-ID 107, lane 9 and 10), AtDGAT1 (SEQ-ID 105, lane 11 and 12), 15 pDGAT2_c699(No) (SEQ-ID 19, lane 13 and 14) and pDGAT2_c2959(No) (SEQ-ID 25, lane 15) encode polypetides having DGAT activity. Table 6 summarizes the results of the LPCAT, LPAAT and DGAT activity tests. 20 Table 6: Measured with microsomal protein and [14C]-18:1-LPA, [14C]-18:1-LPC or [14C] 6:0-1,2-DAG. Ofr the in vitro DGAT assay, 1 mg/ml of BSA was added to reduce activity for staying in the linear range. Enzyme Candidate SEQ-IDs Activity in vitro Activity in Activity Class (ORF / pro- using vitro using in vivo tein / 18:3-CoA 22:6-CoA mRNA) nmol/(mg*min) nmol/(mg*min LPAAT pLPAAT-c6316(No) 13/14/15 81 64 LPCAT pLPAAT-c6316(No) 13/14/15 38 9 DGAT pDGAT2_c699(No) 19/20/21 0,22 0,17 Yes DGAT pDGAT2_c2959(No) 25/26/27 0,95 0,67 Yes DGAT pDGAT2_c4648(No) 34/35/36 1,4 0,17 Yes DGAT pDGAT2_c48271(No) 102/103/104 1,6 0 Yes DGAT pDGAT2-c19425(Ta) 52/53/54 4,0 5,6 Yes DGAT AtDGAT1 105/106/ -- 1,6 1,2 Yes DGAT BnDGAT1 107/108/-- 2,4 1,5 Yes 25 Example 8: Determination of substrate specificity for LPAAT 4195554_1 (GHMattes) P92082.AU.1 For determination of substrate specificities of the LPAAT enzymes, clones of the yeast mu tant Y13749 (described in example 7) harboring LPAAT genes in the pYES plasmid can be grown at 280C in 10ml selective media (SC-URA) with 2% raffinose as carbon source over 5 night. The next day, expression of the acyltransferase polypeptides can be induced by transferring the cells to fresh media containing 2% galactose, for example by inoculating 100 ml of fresh culture to an optical density (measure at 600nm) of OD600=0.1. Cells are harvested after 24h incubation at 280C by centrifugation at 3000 x g for 5 min and resus pended in 1 ml disruption buffer (20 mM Tris/HCL pH 7.6, 10 mM MgCl 2 , 1 mM EDTA, 5% 10 glycerol, 0.3 M (NH 4

)

2

SO

4 ) and disrupted using acid washed zirconium beads (200pm aver age diameter) in a mill (Retsch, Germany) by three minutes agitation at 300rpm. The su pernatant and the beads are transferred to a fresh tube. Disruption buffer is added up to 20 ml and the tube is centrifuged at 8000 x g for 5 min. The obtained supernatant is centri fuged for 2 hrs at 42000 rpm at 40C. The pellet (microsomal fraction) is resuspended in a 15 small volume of 0.1 M phosphate buffer pH 7.2. Protein content in the microsomal fraction is measured according to Bradford (Bradford, M.M. (1976), Anal. Biochem. Bd. 72, pp. 248 254) with bovine serum albumin as standard. Assay mixtures contain 1-5 pg of microsomal protein (the amount is adjusted to achieve linear conditions without substrate limitation), 10 pl of 1 mM [ 14 C]-18:1-LPA (5000 dpm/nmol), 10 pl of 1 mM acyl-CoA in assay buffer (0.1 M 20 phosphate buffer pH 7.2., 10 mg/ml Bovine Serum Albumine (BSA)) to give a total volume of 100 pl. Like to amount of microsomal protein added to the assay, also the amount of BSA has influence on observed anzmye activities, where higher amounts of BSA result on lower activities and lower amounts of BSA result in higher activities. The enzyme specificity can be tested for different acyl-CoA:s, e.g. 14:0-CoA, 16:0-CoA, 18:1-CoA, 18:2-CoA, 18:3 25 CoA, y18:3-CoA, 18:4-CoA, 20:3-CoA, 20:4-CoA, 20:4(n-3)-CoA, 20:5-CoA, 22:5-CoA, 22:6-CoA. Samples are incubated for 4 min at 300C. The assays are terminated by extrac tion of the lipids into chloroform according to Bligh and Dyer (Bligh, E.G. and Dyer, W.J. (1959), Can. J. Biochem. Physiol. 37, pp. 911-917). Lipids are separated on thin layer chromatography (TLC) silica 60 plates (Merck) using chloroform/methanol/acetic acid/water 30 (90:15:10:3), and autoradiographic pictures are taken using an instant imager (Packard). The amount of phosphatidic acid (PA) produced in the reaction (and hence the enzyme ac tivity) can be determined from the picture. Example 9: Determination of substrate specificity for LPLAT 35 For LPCAT and LPEAT activity assay, clones of the yeast mutant Y12431 harboring LPLAT genes in the pYES plasmid can be grown at 280C in 10ml selective media (SC-URA) with 2% raffinose as carbon source over night. The next day, expression of the acyltransferase polypeptides can be induced by transferring the cells to fresh media containing 2% galac 4195554_1 (GHMattes) P92082.AU.1 tose, for example by inoculating 100 ml of fresh culture to an optical density (measure at 600nm) of OD600=0.1 Cells are harvested after 24h incubation at 280C by centrifugation at 3000 x g for 5 min and resuspended in 1 ml disruption buffer (20 mM Tris/HCL pH 7.6, 10 mM MgCl 2 , 1 mM EDTA, 5% glycerol, 0.3 M (NH 4

)

2

SO

4 ) and disrupted using acid washed 5 zirconium beads (200pm average diameter) in a mill (Retsch, Germany) by three minutes agitation at 300rpm. The supernatant and the beads are transferred to a fresh tube. Disrup tion buffer is added up to 20 ml and the tube is centrifuged at 8000 x g for 5 min. The ob tained supernatant is centrifuged for 2 hrs at 42000 rpm at 40C. The pellet (microsomal frac tion) is resuspended in a small volume of 0.1 M phosphate buffer pH 7.2. Protein content in 10 the microsomal fraction is measured according to Bradford (Bradford, M.M. (1976), Anal. Biochem. Bd. 72, pp. 248-254) with bovine serum albumin as standard. Assay mixtures contain either 10pl 1 mM [ 1 4 C]-18:1-Lysophosphatidlycholine (-LPC), 5000 dpm/nmol (LPCAT assay) or 10pl 1 mM [ 14 C]-18:1-Lysophosphatidylethanolamine (-LPE), 5000 dpm/nmol (LPEAT assay), 1-10 pg of microsomal protein (the amount is adjusted to 15 achieve linear conditions without substrate limitation), 10 pl of 1 mM acyl-CoA in assay buf fer (0.1 M phosphate buffer pH 7.2., 10 mg/ml BSA) to give a total volume of 100 pl. Like to amount of microsomal protein added to the assay, also the amount of BSA has influence on observed anzmye activities, where higher amounts of BSA result on lower activities and lower amounts of BSA result in higher activities. The enzyme specificity can be tested for 20 different acyl-CoA:s, e.g. 14:0-CoA, 16:0-CoA, 18:1-CoA, 18:2-CoA, 18:3-CoA, y18:3-CoA, 18:4-CoA, 20:3-CoA, 20:4-CoA, 20:4(n-3)-CoA, 20:5-CoA, 22:5-CoA, 22:6-CoA.. Samples are incubated for 4 min at 300C. The assays are terminated by extraction of the lipids into chloroform according to Bligh and Dyer (Bligh, E.G. and Dyer, W.J. (1959), Can. J. Bio chem. Physiol. 37, pp. 911-917). Lipids are separated on thin layer chromatography (TLC) 25 silica 60 plates (Merck) using chloroform/methanol/acetic acid/water (90:15:10:3), and auto radiographic pictures are taken using an instant imager (Packard). The amount of phospha tidyl choline (PC) or phosphatidyl ethanol amine (PE) produced in the reaction (and hence the enzyme activity) can be determined from the picture. 30 Example 10: Determination of substrate specificity for DGAT For DGAT activity assay, clones of the yeast mutant H1246 harboring either one of pYES pDGAT2_c699(No), pYES-pDGAT2_c2959(No), pYES-pDGAT2_c4648(No), pYES pDGAT2_c48271(No), pYES-pDGAT2-c19425(Ta), pYES-AtDGAT1, or pYES-BnDGAT1 35 can be grown at 280C in 10ml selective media (SC-URA) with 2% raffinose as carbon source over night. The next day, expression of the acyltransferase polypeptides can be in duced by transferring the cells to fresh media containing 2% galactose, for example by in oculating 100 ml of fresh culture to an optical density (measure at 600nm) of OD 6 0 0 =0.1. Cells are harvested after 24h incubation at 280C by centrifugation at 3000 x g for 5 min and 4195554_1 (GHMattes) P92082.AU.1 resuspended in 1 ml disruption buffer (20 mM Tris/HCL pH 7.6, 10 mM MgCl 2 , 1 mM EDTA, 5% glycerol, 0.3 M (NH 4

)

2

SO

4 ) and disrupted using acid washed zirconium beads (200pm average diameter) in a mill (Retsch, Germany) by three minutes agitation at 300rpm. The supernatant and the beads are transferred to a fresh tube. Disruption buffer is added up to 5 20 ml and the tube is centrifuged at 8000 x g for 5 min. The obtained supernatant is centri fuged for 2 hrs at 42000 rpm at 40C. The pellet (microsomal fraction) is resuspended in a small volume of 0.1 M phosphate buffer pH 7.2. Protein content in the microsomal fraction is measured according to Bradford (Bradford, M.M. (1976), Anal. Biochem. Bd. 72, pp. 248 254) with bovine serum albumin as standard. Assay mixtures contain 5 pl 1 mM [14C]-6:0 10 DAG, 3000 dpm/nmol, 1-100 pg of microsomal protein (the amount is adjusted to achieve linear conditions without substrate limitation), 5 pl of 1 mM acyl-CoA in assay buffer (50 mM Hepes buffer pH 7.2, 1 mg/ml BSA) to give a total volume of 100 pl. The enzyme specificity can be tested for different acyl-CoA:s, e.g. 14:0-CoA, 16:0-CoA, 18:1-CoA, 18:2-CoA, 18:3 CoA, y18:3-CoA, 18:4-CoA, 20:3-CoA, 20:4-CoA, 20:4(n-3)-CoA, 20:5-CoA, 22:5-CoA, 15 22:6-CoA.. Samples are incubated for 4 min at 300C. The assays are terminated by extrac tion of the lipids into chloroform according to Bligh and Dyer (Bligh, E.G. and Dyer, W.J. (1959), Can. J. Biochem. Physiol. 37, pp. 911-917).Lipids are separated on thin layer chromatography (TLC) silica 60 plates (Merck) using hexane:diethylether:acetic acid (70:30:1), and autoradiographic pictures are taken using an instant imager (Packard). The 20 amount of triacylglycerol (TAG) produced in the reaction (and hence the enzyme activity) can be determined from the picture. In Brassica napus and Arabidopsis, the DGAT involved in TAG-formation in seeds are of the DGAT1 type. The enzyme activity AtDGAT1 and BnDGAT1 for the different substrates can be seen in figure 9. The enzyme activity of pDGAT2-c19425(Ta) for the different substrates, compared to AtDGAT1 and BnDGAT1 is 25 shown in figure 10. The enzyme activity of pDGAT2_c699(No) and pDGAT2_c4648(No) for the different substrates, compared to AtDGAT1 and BnDGAT1 is shown in figure 11. The data in figure 10 and 11 show clearly, that all DGAT2 enzymes shown in these figures vary strongly towards their activities for the various substrates, whereas the DGAT1 involved in TAG formation in Arabidopsis and Brassica napus exhibit less variability towards these dif 30 ferent substrates. Example 11: Determination of substrate selectivity for LPAAT For determination of substrate selectivities of the LPAAT enzymes, clones of the yeast mu 35 tant Y13749 (described in example 7) harboring LPAAT genes can be grown at 280C in 10ml selective media (SC-URA) with 2% raffinose as carbon source over night. The next day, expression of the acyltransferase polypeptides can be induced by transferring the cells to fresh media containing 2% galactose, for example by inoculating 100 ml of fresh culture to an optical density (measure at 600nm) of OD 60 0 =0.1. Cells are harvested after 24h incu 4195554_1 (GHMattes) P92082.AU.1 bation at 280C by centrifugation at 3000 x g for 5 min and resuspended in 1 ml disruption buffer (20 mM Tris/HCL pH 7.6, 10 mM MgCl 2 , 1 mM EDTA, 5% glycerol, 0.3 M (NH 4

)

2

SO

4 ) and disrupted using acid washed zirconium beads (200pm average diameter) in a mill (Retsch, Germany) by three minutes agitation at 300rpm. The supernatant and the beads 5 are transferred to a fresh tube. Disruption buffer is added up to 20 ml and the tube is centri fuged at 8000 x g for 5 min. The obtained supernatant is centrifuged for 2 hrs at 42000 rpm at 40C. The pellet (microsomal fraction) is resuspended in a small volume of 0.1 M phos phate buffer pH 7.2. Protein content in the microsomal fraction is measured according to Bradford (Bradford, M.M. (1976), Anal. Biochem. Bd. 72, pp. 248-254) with bovine serum 10 albumin as standard. The substrate selectivity can be determined by mixing equimolar amounts of different acyl-CoA:s in the same reaction and measure the preference for using the different acyl groups as substrates. The assay is run as in the specificity studies (Exam ple 5) but scaled up 18 times to get sufficient amount of PA for detection. Up to 4 different acyl-CoA:s can be used in the assay in equimolar amount instead of one single acyl-CoA. 15 Samples are incubated for 4 min at 300C. The assays are terminated by extraction of the lipids into chloroform according to Bligh and Dyer (Bligh, E.G. and Dyer, W.J. (1959), Can. J. Biochem. Physiol. 37, pp. 911-917). Lipids are separated on thin layer chromatography (TLC) silica 60 plates (Merck) using chloroform/methanol/acetic acid/water (90:15:10:3), and autoradiographic pictures are taken using an instant imager (Packard). The phosphatid 20 ic acid (PA) is recovered from the plate and the fatty acids methylated in situ on the gel with sulphuric acid (2%) in methanol. Fatty acid methyl esters are extracted with hexane and separated by gas-liquid chromatography (GLC) using a WCOT fused silica 50 mxO.32 mm ID capillary column coated with CP-Wax 58-CB DF = 0.3 (Chrompack inc., The Nether lands) and quantified relative to methyl-heptadecanoate added as an internal standard. The 25 selectivity can be determined by calculating the amount of each acyl group that has been acylated to LPA. Example 12: Determination of substrate selectivity for LPLAT 30 For LPCAT and LPEAT activity assay, clones of the yeast mutant Y12431 harboring LPLAt genes can be grown at 280C in 10ml selective media (SC-URA) with 2% raffinose as car bon source over night. The next day, expression of the acyltransferase polypeptides can be induced by transferring the cells to fresh media containing 2% galactose, for example by inoculating 100 ml of fresh culture to an optical density (measure at 600nm) of OD 6 00 =0.1 35 Cells are harvested after 24h incubation at 280C by centrifugation at 3000 x g for 5 min and resuspended in 1 ml disruption buffer (20 mM Tris/HCL pH 7.6, 10 mM MgCl 2 , 1 mM EDTA, 5% glycerol, 0.3 M (NH 4

)

2

SO

4 ) and disrupted using acid washed zirconium beads (200pm average diameter) in a mill (Retsch, Germany) by three minutes agitation at 300rpm. The supernatant and the beads are transferred to a fresh tube. Disruption buffer is added up to 4195554_1 (GHMattes) P92082.AU.1 20 ml and the tube is centrifuged at 8000 x g for 5 min. The obtained supernatant is centri fuged for 2 hrs at 42000 rpm at 40C. The pellet (microsomal fraction) is resuspended in a small volume of 0.1 M phosphate buffer pH 7.2. Protein content in the microsomal fraction is measured according to Bradford (Bradford, M.M. (1976), Anal. Biochem. Bd. 72, pp. 248 5 254) with bovine serum albumin as standard. The substrate selectivity can be determined by mixing equimolar amounts of different acyl-CoA:s in the same reaction and measure the preference for using the different acyl groups as substrates. The assay is run as in the spe cificity studies (Example 6) but scaled up 18 times to get sufficient amount of PC or PE for detection. Up to 4 different acyl-CoA:s can be used in the assay in equimolar amount in 10 stead of one single acyl-CoA. Samples are incubated for 4 min at 300C. The assays are terminated by extraction of the lipids into chloroform according to Bligh and Dyer (Bligh, E.G. and Dyer, W.J. (1959), Can. J. Biochem. Physiol. 37, pp. 911-917). Lipids are sepa rated on thin layer chromatography (TLC) silica 60 plates (Merck) using chloro form/methanol/acetic acid/water (90:15:10:3), and autoradiographic pictures are taken using 15 an instant imager (Packard). The PC or PE is recovered from the plate and the fatty acids methylated in situ on the gel with sulphuric acid (2%) in methanol. Fatty acid methyl esters are extracted with hexane and separated by gas-liquid chromatography (GLC) using a WCOT fused silica 50 mxO.32 mm ID capillary column coated with CP-Wax 58-CB DF = 0.3 (Chrompack inc., The Netherlands) and quantified relative to methyl-heptadecanoate added 20 as an internal standard. The selectivity can be determined by calculating the amount of each acyl group that has been acylated to LPC or LPE. Example 13: Determination of substrate selectivity for DGAT 25 For DGAT activity assay, clones of the yeast mutant H1246 harboring DGAT genes can be grown at 280C in 10ml selective media (SC-URA) with 2% raffinose as carbon source over night. The next day, expression of the acyltransferase polypeptides can be induced by transferring the cells to fresh media containing 2% galactose, for example by inoculating 100 ml of fresh culture to an optical density (measure at 600nm) of OD600=0.1. Cells are 30 harvested after 24h incubation at 28 0 C by centrifugation at 3000 x g for 5 min and resus pended in 1 ml disruption buffer (20 mM Tris/HCL pH 7.6, 10 mM MgCl 2 , 1 mM EDTA, 5% glycerol, 0.3 M (NH 4

)

2

SO

4 ) and disrupted using acid washed zirconium beads (200pm aver age diameter) in a mill (Retsch, Germany) by three minutes agitation at 300rpm. The su pernatant and the beads are transferred to a fresh tube. Disruption buffer is added up to 20 35 ml and the tube is centrifuged at 8000 x g for 5 min. The obtained supernatant is centri fuged for 2 hrs at 42000 rpm at 4 0 C. The pellet (microsomal fraction) is resuspended in a small volume of 0.1 M phosphate buffer pH 7.2. Protein content in the microsomal fraction is measured according to Bradford (Bradford, M.M. (1976), Anal. Biochem. Bd. 72, pp. 248 254) with bovine serum albumin as standard. The substrate selectivity can be determined 4195554_1 (GHMattes) P92082.AU.1 by mixing equimolar amounts of different acyl-CoA:s in the same reaction and measure the preference for using the different acyl groups as substrates. The assay is run as in the spe cificity studies (Example 7) but scaled up 18 times to get sufficient amount of TAG for de tection. Up to 4 different acyl-CoA:s can be used in the assay in equimolar amount instead 5 of one single acyl-CoA. Samples are incubated for 4 min at 300C. The assays are termi nated by extraction of the lipids into chloroform according to Bligh and Dyer (Bligh, E.G. and Dyer, W.J. (1959), Can. J. Biochem. Physiol. 37, pp. 911-917). Lipids are separated on thin layer chromatography (TLC) silica 60 plates (Merck) using chloroform/methanol/acetic ac id/water (90:15:10:3), and autoradiographic pictures are taken using an instant imager 10 (Packard). The TAG is recovered from the plate and the fatty acids methylated in situ on the gel with sulphuric acid (2%) in methanol. Fatty acid methyl esters are extracted with hexane and separated by gas-liquid chromatography (GLC) using a WCOT fused silica 50 mxO.32 mm ID capillary column coated with CP-Wax 58-CB DF = 0.3 (Chrompack inc., The Nether lands) and quantified relative to methyl-heptadecanoate added as an internal standard. The 15 selectivity can be determined by calculating the amount of each acyl group that has been acylated to TAG. 4195554_1 (GHMattes) P92082.AU.1

Claims (19)

1. A vector comprising a polynucleotide, wherein the polynucleotide comprises a nucle ic acid sequence selected from the group consisting of: a) a nucleic acid sequence having a nucleotide sequence as shown in any one of 5 SEQ ID NOs: 52 and 54; b) a nucleic acid sequence encoding a polypeptide having an amino acid sequence as shown in SEQ ID NO: 53, c) a nucleic acid sequence being at least 60% identical to the nucleic acid se quence of a) or b), wherein said nucleic acid sequence encodes a polypeptide 0 having acyltransferase activity.

2. The vector of claim 1, wherein said polynucleotide further comprises an expression control sequence operatively linked to the said nucleic acid sequence. 5

3. The vector of claim 1 or 2, wherein said polynucleotide further comprises a termina tor sequence operatively linked to the nucleic acid sequence.

4. An expression vector comprising a polynucleotide, wherein the polynucleotide comprises a nucleic acid sequence se .0 lected from the group consisting of: a) a nucleic acid sequence having a nucleotide sequence as shown in any one of SEQ ID NOs: 52 and 54; b) a nucleic acid sequence encoding a polypeptide having an amino acid sequence as shown in SEQ ID NO: 53, '5 c) a nucleic acid sequence being at least 60% identical to the nucleic acid se quence of a) or b), wherein said nucleic acid sequence encodes a polypeptide hav ing acyltransferase activity.

5. A transgenic host cell comprising the vector of claim 4, or a heterologous polynucleo 30 tide comprising a nucleic acid sequence selected from the group consisting of: a) a nucleic acid sequence having a nucleotide sequence as shown in any one of SEQ ID NOs: 52 and 54; b) a nucleic acid sequence encoding a polypeptide having an amino acid sequence as shown in SEQ ID NO: 53, 35 c) a nucleic acid sequence being at least 60% identical to the nucleic acid se quence of a) or b), wherein said nucleic acid sequence encodes a polypeptide having acyltransferase activity.

6. A method for the manufacture of a polypeptide encoded by a polynucleotide com 40 prising a nucleic acid sequence selected from the group consisting of: a) a nucleic acid sequence having a nucleotide sequence as shown in any one of 7264326_1 (GHMatters) P92082.AU.1 CLAIREG SEQ ID NOs: 52 and 54; b) a nucleic acid sequence encoding a polypeptide having an amino acid sequence as shown in SEQ ID NO: 53, c) a nucleic acid sequence being at least 60% identical to the nucleic acid se 5 quence of a) or b), wherein said nucleic acid sequence encodes a polypeptide having acyltransferase activity; the method comprising, i) cultivating the host cell of claim 5 under conditions which allow for the production of the said polypeptide; and 0 ii) obtaining the polypeptide from the host cell of step i).

7. A polypeptide which is obtained by the method of claim 6 or encoded by a polynu cleotide comprising a nucleic acid sequence selected from the group consisting of: a) a nucleic acid sequence having a nucleotide sequence as shown in any one of 5 SEQ ID NOs: 52 and 54; b) a nucleic acid sequence encoding a polypeptide having an amino acid sequence as shown in SEQ ID NO: 53, c) a nucleic acid sequence being at least 60% identical to the nucleic acid se quence of a) or b), wherein said nucleic acid sequence encodes a polypeptide .0 having acyltransferase activity.

8. A non-human transgenic organism comprising or the vector of any one of claims 1 to 4, or a heterologous polynucleotide comprising a nucleic acid sequence selected from the group consisting of: '5 a) a nucleic acid sequence having a nucleotide sequence as shown in any one of SEQ ID NOs: 52 and 54; b) a nucleic acid sequence encoding a polypeptide having an amino acid sequence as shown in SEQ ID NO: 53, c) a nucleic acid sequence being at least 60% identical to the nucleic acid se 30 quence of a) or b), wherein said nucleic acid sequence encodes a polypeptide having acyltransferase activity.

9. The non-human transgenic organism of claim 8, which is a microorganism, a plant, plant part, or plant seed. 35

10. A method for the manufacture of polyunsaturated fatty acids comprising: a) cultivating the host cell of claim 5 under conditions which allow for the production of polyunsaturated fatty acids in said host cell; and b) obtaining said polyunsaturated fatty acids from the said host cell. 40

11. A method for the manufacture of polyunsaturated fatty acids comprising: 7264326_1 (GHMatters) P92082.AU.1 CLAIREG a) cultivating the non-human transgenic organism of claim 8 or 9 under conditions which allow for the production of polyunsaturated fatty acids in said host cell; and b) obtaining said polyunsaturated fatty acids from the said non-human transgenic 5 organism.

12. The method of claim 10 or 11, wherein said polyunsaturated fatty acid is arachidonic acid (ARA), eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA). 0

13. A method for the manufacture of an oil, lipid or fatty acid composition comprising the steps of the method of any one of claims 10 to 12 and the further step of formulating the polyunsaturated fatty acid as oil, lipid or fatty acid composition.

14. The method of claim 13, wherein said oil, lipid or fatty acid composition is to be used 5 for feed, foodstuffs, cosmetics or pharmaceuticals.

15. Oil, lipids or fatty acids or a fraction thereof produced by the method of any one of claims 10 to 12. .0

16. An oil, lipid or fatty acid composition comprising a polyunsaturated fatty acid ob tained by the method of any one of claims 10 to 12.

17. An isolated antibody or a fragment derived thereof as an antigen which specifically recognizes a polypeptide encoded by the nucleic acid sequences selected from the '5 group consisting of: a) a nucleic acid sequence having a nucleotide sequence as shown in any one of SEQ ID NOs: 52 and 54; b) a nucleic acid sequence encoding a polypeptide having an amino acid sequence as shown in SEQ ID NO: 53, 30 c) a nucleic acid sequence being at least 60% identical to the nucleic acid se quence of a) or b), wherein said nucleic acid sequence encodes a polypeptide having acyltransferase activity.

18. A feed, feedstuff, cosmetic or pharmaceutical comprising the oil, lipid or fatty acid 35 composition according to claim 16.

19. The vector of claim 1 or claim 4, the transgenic host cell of claim 5, the method of any one of claims 10, 11 or 13, the polypeptide of claim 7, the non-human transgenic organism of claim 8, the lipids or fatty acids or a fraction thereof of claim 15, the oil, 40 lipid or fatty acid composition of claim 16, the antibody or fragment thereof of claim 17, or the feed, feedstuff, cosmetic or pharmaceutical of claim 18, substantially as 7264326_1 (GHMatters) P92082.AU.1 CLAIREG hereinbefore described with reference to the Examples, excluiding, if any compara tive Examples. 7264326_1 (GHMatters) P92082.AU.1 CLAIREG