A kind of fusion protein
Technical field
The present invention relates to biomedicine field, particularly relate to a kind of fusion protein.
Background technology
Phosphatidylserine (phosphatidylserine, PS), is the phospholipid that generally exists of a class, is usually located at eucaryon
The internal layer of cell membrane, is one of cell membrane component.Under normal physiological conditions, there is unsymmetry in the distribution of cytoplasma membrane fat,
This is owing to there is a kind of phospholipid translocase in cytoplasma membrane, can be specifically by Phosphatidylserine (PS) and phosphatidyl second
Hydramine (PE) is transported to the endite of film, and meanwhile, the flippase in another cytoplasma membrane is responsible for Phosphatidylserine
(PS) it is transported to cytoplasma membrane exite with phosphatidylcholine (PC).Film is worked by both enzymes simultaneously, but flippase is anti-
Answer speed than translocase slow 10 times.The two enzymatic reaction is the most independently carried out, i.e. when the activity inhibited of flippase, and indexing
Enzyme is the most active.Under normal physiological conditions, the effect of both enzymes is mutually coordinated, causes in film asymmetric point of main phospholipid
Cloth, i.e. sphingomyelins (SM) and phosphatidylcholine (PC) integrated distribution at cytoplasma membrane exite, and Phosphatidylserine (PS) with
PHOSPHATIDYL ETHANOLAMINE (PE) integrated distribution is in cytoplasma membrane endite.This film fat unsymmetry distribution be cell one from
My protection mechanism, has close with cell recognition, endocytosis with the development of outer row, blood coagulation and some disease such as thrombosis, autoimmune disease etc.
Cut relation.
Research finds, sustains damage at cell or early apoptosis (Apoptosis, also known as programmed cell death) occurs
Time, Phosphatidylserine there will be phenomenon of turning up: i.e. electronegative on bilayer lipid membrane serine from original towards cytoplasm
Becoming outside cell membrane, it produces principle or mechanism is the most fully aware of.At Cell Lab, people would generally use fluorescence mark
Annexin A5 (Annexin A5, former title Annexin V) and the propidium iodide of note detect, distinguish in cultured cell in vitro
Normal, early apoptosis and dead cell.
Annexin-V, calcium ion dependency phospholipid combines one of member of annexin family (ANXA1-ANXA13), is
Molecular weight is the Ca of 35~36KD2+Dependency cardiolipin binding protein, can be specific binding with PS high-affinity.By Annexin-V
Carry out fluorescein (FITC, PE) or biotin labelling, using the Annexin-V that marked as fluorescent probe, utilize fluidic cell
Instrument or fluorescence microscope can detect apoptotic generation.Propidium iodide (propidine iodide, PI) is a kind of nucleic acid dye
Material, it can not be through complete cell membrane, but at the cell of apoptosis middle and advanced stage and dead cell, PI can make thin through cell membrane
The red dye of karyon.Therefore Annexin-V with PI is mated use, it is possible to cell and the dead cell in apoptosis early late period are distinguished
Come.
In early days apoptosis clinically with a series of diseases such as brain and myocardial ischemic injury, neural degeneration, from
Body immune disease and malignant entity tumor damage etc. are relevant.But said method is difficult to realize Phosphatidylserine in vivo
The spike of the effect of turning up and drug targeting.
The feature that the Phosphatidylserine turned up on apoptotic cell film in view of annexin A5 is combined, the present invention will be to will
The monoclonal antibody of Phosphatidylserine, annexin A5 and derivative recombiant protein thereof and radiosiotope, medicine, albumen or
Luminous agent coupling (is merged), for spike (Tracer), development (Imaging), chemotherapy or the phototherapy of diseased tissue.
Summary of the invention
For solving above-mentioned technical problem, it is an object of the invention to provide a kind of immunologic cytotoxicity cell expressing this albumen or dry
Cell has tissue infiltration or at diseased tissue, damage location accumulation ability, can be used for the spike of diseased tissue, development, chemotherapy
Or the fusion protein of phototherapy.
First aspect present invention provides a kind of fusion protein, including the first peptide fragment district and the second peptide fragment district, described first peptide
The C end in section district and the N end in the second peptide fragment district are connected;Wherein, described first peptide fragment district includes secreting signal peptide and phosphatidyl silk
Propylhomoserin associated proteins peptide fragment, described second peptide fragment district includes joining peptide and cross-film peptide fragment, and described Phosphatidylserine combines
Albumen peptide fragment includes the peptide fragment in anti-phosphatidylserine antibody or annexin with Phosphatidylserine specific bond.
Concrete, the aminoacid sequence of described joining peptide is as shown in SEQ ID NO:12;By 15 special acids
Flexible peptide chain become split-phase coupling with cross-film, being changed into can be on eukaryotic cell membrane, on medical peplos or other lipid
The memebrane protein that on double-decker, grappling is expressed or existed.
Concrete, described Phosphatidylserine associated proteins peptide fragment includes in annexin A5 special with Phosphatidylserine
In conjunction with peptide fragment.
Concrete, the aminoacid sequence in described first peptide fragment district is as shown in SEQ ID NO:13.
Fusion protein in the present invention, its intracellular cytoplasmic district can be non-functional oligopeptide, can also be at cross-film peptide fragment
C end connect and have one or more the signal transduction peptide fragment with cell regulatory function.
Wherein, signal transduction peptide fragment is excitatoty or inhibition, such as, have excitatory stimulation effect to immunocyte
The endochylema peptide fragment of CD3zeta molecule and there is the endochylema peptide fragment of CD28 molecule of common stimulation;That is, described signal transduction
Peptide fragment includes the endochylema peptide fragment of CD3zeta molecule and/or the endochylema peptide fragment of CD28 molecule.
Concrete, the aminoacid sequence of shown fusion protein is as shown in SEQ ID NO:8 or 11.
Second aspect present invention provides a kind of nucleic acid molecules, and it comprises can encode aforesaid fusion protein.
Concrete, the nucleotide sequence of described nucleic acid molecules is as shown in SEQ ID NO:7 or 10.
Third aspect present invention relates to carrier, and it contains the nucleic acid molecules of any one of second aspect present invention.
Hereinafter the present invention is described further:
The polynucleotide encoding certain albumen can be inserted it should be noted that, the term " carrier " in the present invention refers to
Enter wherein and make albumen obtain a kind of nucleic acid vehicle expressed.Carrier by converting, can be transduceed or transfection host cell, makes
The hereditary material element that it carries is expressed at host cell inner expression.For example, carrier includes: plasmid;Phasmid;Ke
This plasmid;It is artificially colored that artificial chromosome such as yeast artificial chromosome (YAC), bacterial artificial chromosome (BAC) or P1 originate
Body (PAC);Phage such as bacteriophage lambda or M13 phage and animal virus etc..Animal virus kind as carrier has reverse transcription
Enzymophathy poison (including slow virus), adenovirus, adeno-associated virus, herpesvirus (such as herpes simplex virus), poxvirus, shaft-like disease
Poison, human papillomavirus, papova viruses (such as SV40).The element that a kind of carrier may be expressed containing various control, bag
Include promoter sequence, transcriptional initiation sequence, enhancer sequence, selection element and reporter gene.It addition, carrier also can be containing replicating
Initiation site.Carrier is it is also possible to include and assist it to enter the composition of cell, such as virion, liposome or protein coat,
But not only only have these materials.
In the present invention can the carrier of expressed fusion protein, transfected by plasmid, viral vector or infestation with virus particles, electricity turn
Etc. mode, can be at any eukaryotic cell, such as (granulocyte, NK cell, dendritic cell, T lymphocyte, B drench immunocyte
Bar cell, macrophage or other blood cells), stem cell (embryonic stem cell, placenta stem-cell, umbilical cord stem cells, Cord blood
Stem cell, bone marrow stem cell, hematopoietic stem cell, mescenchymal stem cell, adult stem cell, CFU-GM, iPSC and other have
The various tissue stem cells of versatility) various host cell inner expressions.
In the present invention, term " polypeptide " refers to the chemical combination referring to that a-amino acid is formed so that peptide bond links together
Thing, is also the intermediate product of proteolysis.Generally by the compound of 10-100 amino acid molecular dehydrating condensation polypeptide,
Their molecular weight is less than 10,000Da (Dalton, dalton), can pass through semipermeable membrane, not sunk by trichloroacetic acid and ammonium sulfate
Form sediment.Also by document, the peptide being made up of 2-10 aminoacid is called oligopeptide (small-molecular peptides);The peptide of 10-50 aminoacid composition claims
For polypeptide;The peptide being made up of the aminoacid of more than 50 is known as protein;In other words, broadly, protein the most also by
It is referred to as polypeptide.Term " peptide fragment ", refers in polypeptide or protein molecule, have a certain specific function by multiple aminoacid groups
The peptide become.
In the present invention, term " apoptosis " refers to " programmed cell death " that certain reason causes, and is different from it
The cytolytic of his type is dead.
In the present invention, term " cell homing ability " refers to different cell and migrates through blood circulation tropism and be settled in certain
Plant the character of the specific region of tissue.Such as lymphocyte homing and stem cell homing.
In the present invention, term " costimulatory signal molecule " (Co-stimulating molecule) refers to immunocyte
Some adhesion molecules on surface, such as CD28, CD134/OX40, CD137/4-1BB, CD40 etc., by being combined with its part, activate
The secondary signal of immunocyte, strengthens multiplication capacity and the secretory function of cytokine of immunocyte, extends activated immune thin
The time-to-live of born of the same parents.
In the present invention, term " extracellular region " and " the outer peptide fragment of born of the same parents " refer to that memebrane protein is positioned at extracellular peptide chain section.
In the present invention, term " cross-film district " and " cross-film peptide fragment " refer to that memebrane protein is positioned at the peptide of cell bilayer lipid membrane
Chain section.
In the present invention, term " cytoplasmic domain " and " endochylema peptide fragment " refer to that memebrane protein is positioned at intracellular peptide chain section.
By such scheme, the present invention at least has the advantage that utilization gene recombination technology ties Phosphatidylserine
Hop protein, such as anti-phosphatidylserine antibody or annexin A5, is transformed into the fusion protein of grappling on cell membrane.By tool
There is the annexin A5 at disease injury position accumulation ability to become a part for various functional cell, such as, there is tumor and kill
The T lymphocyte of wound effect and the mescenchymal stem cell with reproducibility repair function, so that the homing ability of functional cell
It is changed as possibility;According to cell type and application target, recombinant expressed annexin A5 can be from different intracellular tune
Joint signal fused, thus change the partial function of this cell.
Described above is only the general introduction of technical solution of the present invention, in order to better understand the technological means of the present invention,
And can be practiced according to the content of description, below with presently preferred embodiments of the present invention and coordinate accompanying drawing describe in detail as after.
Accompanying drawing explanation
Fig. 1 is fusion protein construction schematic diagram in the present invention;
Fig. 2 is pEGFP-N1-776linker enzyme action result figure in first embodiment of the invention;
Fig. 3 is pIres2-clone 5-28Z-EGFP enzyme action result figure in first embodiment of the invention;
Fig. 4 is fusion protein expression of results figure in eukaryotic cell in first embodiment of the invention;
Fig. 5 is fusion protein fluorogram after antibodies in first embodiment of the invention;
Fig. 6 is to transfect " pEGFP-N1-Clone 5-776linker " in second embodiment of the invention after 24 hours
HEK293 cell fluorescence figure;
Fig. 7 is to transfect " pEGFP-N1-Clone 5-314linker " in first embodiment of the invention after 24 hours
HEK293 cell fluorescence figure;
Fig. 8 is that in second embodiment of the invention, the HEK293 streaming of transfection " pEGFP-N1-Clone 5-776linker " is thin
Born of the same parents' instrument testing result figure;
Fig. 9 is that in first embodiment of the invention, the HEK293 streaming of transfection " pEGFP-N1-Clone 5-314linker " is thin
Born of the same parents' instrument testing result figure.
Detailed description of the invention
Below in conjunction with the accompanying drawings and embodiment, the detailed description of the invention of the present invention is described in further detail.Hereinafter implement
Example is used for illustrating the present invention, but is not limited to the scope of the present invention.
Embodiment 1 film expression functional annexin A5 fusion protein construction and expression
The present embodiment provides a kind of fusion protein, its building mode as shown in Figure 1B, including the first peptide fragment district and the second peptide
Section district, the first peptide fragment district includes secreting signal peptide and Phosphatidylserine associated proteins peptide fragment, and the second peptide fragment district includes connecting
Peptide fragment, cross-film peptide fragment and there is the signal transduction peptide fragment of cell regulatory function.Specific experiment step is as follows:
1, fusion protein the second peptide fragment district builds
Choose commercial eukaryon expression plasmid pEGFP-N1 (SEQ ID NO:1) as carrier.Gene chemical synthesis coding merges egg
The nucleotide sequence (SEQ ID NO:2) in white second peptide fragment district, this sequence comprises Hind III site, Kozak successively from 5 ' ends
Sequence gccacc, translation initiation password ATG, 3xGGGGS peptide chain nucleic acid sequence encoding (SEQ ID NO:12), CD8a fragment
(382nt-630nt in P01732-1), CD28 fragment (538nt-660nt in P10747-1), CDzeta fragment are (in P20963-1
154nt-491nt), BamHI site.Wherein, 3xGGGGS peptide chain nucleic acid sequence encoding coding joining peptide, CD8a fragment coding
Cross-film peptide fragment, CD28 fragment and CDzeta fragment coding signal transduction peptide fragment.
After double-strand cDNA in the second peptide fragment district being processed with restriction endonuclease Hind III and BamHI, access what double ferment treatment was crossed
Carrier pEGFP-N1, obtains product " pEGFP-N1-776linker ";Enzyme action result as in figure 2 it is shown, in figure A band be non-enzyme action
Plasmid, B band is HindIII and BamHI double digestion product (inserting gene 776bp), and C band is the big small tenon of nucleic acid molecules
Will thing, result shows that carrier is normal, comprises the nucleotide sequence in encoding fusion protein the second peptide fragment district.
2, fusion protein the first peptide fragment district builds
The nucleotide sequence (SEQ ID NO:3) in gene chemical synthesis encoding fusion protein the first peptide fragment district, this sequence is from 5 ' ends
Comprise successively NheI site, CD8a secretion signal fragments of peptides (1nt-63nt in P01732-1), annexin A5 (in P08758 compile
Code base 4nt-960nt), BglII site, access the plasmid pIres2-28Z-EGFP of commercial plasmid pIres2-EGFP
(SEQ ID NO:4), obtains plasmid pIres2-clone5-28Z-EGFP, and enzyme action result is as it is shown on figure 3, band a is nucleic acid divides
Sub-size mark, band b is NheI and BglII double digestion product (inserting gene 1020bp), and band c is non-enzyme action matter
Grain, result shows that carrier is normal, comprises the nucleotide sequence in encoding fusion protein the first peptide fragment district.
3, fusion protein vector construction
Design PCR cloned upstream primer GAagatctgccaccATGGCCTTACCAGTGACCG (SEQ ID NO:5) and under
Trip primer cgaagcttGTCATCTTCTCCACAGAG (SEQ ID NO:6), through standard PCR amplification, uses agarose gel electrophoresis
Rear purified pcr product, processes through double digestion, accesses " pEGFP-N1-776linker ";Gained plasmid is errorless through order-checking inspection.Institute
Obtaining fusion plasmid is " pEGFP-N1-Clone 5-776linker ", and its functional annexin A5 of film expression expressed merges egg
White nucleotide sequence is as shown in SEQ ID NO:7, and its aminoacid sequence is as shown in SEQ ID NO:8.
4, expressing fusion protein
Gained plasmid " pEGFP-N1-Clone 5-776linker " through recombinant, amplify and prepare after, for true
The detection of expression of nucleus.HEK293 cell is inoculated in 6 orifice plates, until 70-80% saturation, with in Lip2000 transfection
Stating plasmid to 293 cells, after 24 hours, with appropriate anti-rabbit antienzyme connection protein A 5 multi-resistance, (Yi Qiao Divine Land, Beijing biotechnology is public
Department) incubate temperature 30 minutes with cell at 37 DEG C, normal saline cleans twice;Anti-PE labelling goat anti-rabbit igg (H+L) that adds two again,
Incubate temperature 15 minutes for 37 DEG C, after normal saline cleans twice, observation of cell fluorescence.Under same eyepiece frame, change color filter film, portion
Divide cell to show the PE red fluorescence (Fig. 5) of antibody staining, table on intracytoplasmic EGFP green fluorescence (Fig. 4) and cell membrane simultaneously
Bright functional annexin A5 fusion protein is anchored on outside cell membrane in intracellular correct expression and annexin A5.
Embodiment 2 film expression non-functional annexin A5 fusion protein construction and expression
The present embodiment provides a kind of fusion protein, its building mode as shown in Figure 1A, including the first peptide fragment district and the second peptide
Section district, the first peptide fragment district includes secreting signal peptide and Phosphatidylserine associated proteins peptide fragment, and the second peptide fragment district includes connecting
Peptide fragment and cross-film peptide fragment.Specific experiment step is as follows:
1, fusion protein the second peptide fragment district builds
The nucleotide sequence (SEQ ID NO:9) in gene chemical synthesis encoding fusion protein the second peptide fragment district, this sequence is from 5 ' ends
Comprise successively Hind III site, Kozak sequence gccacc, translation initiation password ATG, 3xGGGGS peptide chain nucleic acid sequence encoding,
CD8a fragment (382nt-629nt in P01732-1), BamHI site.
2, fusion protein vector construction
Compared with fusion protein the second peptide fragment district in embodiment one, the costimulatory signal peptide of CD28 and the letter of CD3zeta
Number peptide-coding sequence has removed, and only comprises nine intracellular amino acids of CD8a;Access plasmid " pEGFP-N1-
776linker”.Gained plasmid " pEGFP-N1-Clone 5-314linker " is errorless through order-checking inspection, its film expression expressed
The nucleotide sequence of non-functional annexin A5 fusion protein as shown in SEQ ID NO:10, its aminoacid sequence such as SEQ ID
Shown in NO:11.
3, expressing fusion protein
Gained plasmid " pEGFP-N1-Clone 5-314linker " and " pEGFP-N1-Clone 5-776linker " warp
Recombinant, amplify and prepare after, for the detection of expression of eukaryotic cell.HEK293 cell is inoculated in 6 orifice plates, waits until
During 70-80% saturation, with the Lip2000 above-mentioned plasmid of transfection to 293 cells, after 24 hours, observe and record annexin A5
Fusion protein expresses the green EGFP fluorescence of display at cell, and result is respectively as shown in Fig. 7 and Fig. 6.
Transfectional cell in six orifice plates is collected after pancreatin processes, PBS three times, with an appropriate anti-rabbit antienzyme connection albumen
A5 multi-resistance (Yi Qiao Divine Land, Beijing biotech company) incubates temperature 15 minutes with cell at 37 DEG C, PBS twice;The anti-PE that adds two again
Labelling goat anti-rabbit igg (H+L), 37.DEG C incubate temperature 10 minutes, after PBS twice, with flow cytomery EGFP and PE
Signal.EGFP signal shows, whether film expression functional annexin A5 fusion protein (pEGFP-N1-Clone 5-
776linker, Fig. 8), or film expression non-functional annexin A5 fusion protein (pEGFP-N1-Clone 5-
314linker, Fig. 9), annexin A5 fusion protein is all in intracellular correct expression, and PE signal shows at the outer anchor of cell membrane
Fixed annexin A5 three-dimensional conformation does not change, prompting annexin A5 functional normally.
The above is only the preferred embodiment of the present invention, is not limited to the present invention, it is noted that for this skill
For the those of ordinary skill in art field, on the premise of without departing from the technology of the present invention principle, it is also possible to make some improvement and
Modification, these improve and modification also should be regarded as protection scope of the present invention.