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@#Objective To compare the effects of different signal peptides on the secretion and expression of SARS-CoV-2S1,receptor binding domain(RBD) and RBD dimer proteins in Expisf9 insect cells.Methods The gene sequences of three proteins,SARS-CoV-2 S1(M1-E661),RBD(R319-P545) and RBD dimer(R319-K537 tandem),were selected and divided into 25 groups according to the different N-terminal signal peptide sequences(Endo,honeybee melittin(HBM),GP64,GP67,chitinase(Chi) and HIV-ENV) and C-terminal label sequences.25 recombinant baculoviruses were constructed by Bac-to-Bac system,and 25 groups of tertiary strain banks were prepared.B2 and C4 viruses were inoculated to logarithmic prestage cells(2.8 × 10~6 cells/mL) and logarithmic metaphase cells(1.2 × 10~7 cells/mL),respectively.The viruses of each group were cultured to 100 mL(500 mL shaker) for protein expression,and samples were taken for SDSPAGE electrophoresis,Western-blot and ELISA detection.Two groups with higher expression levels of S1,RBD and RBD dimer proteins were selected for repeated verification.Results When B2 and C4 were inoculated to high cell density,the secretion expression level showed no increase,while there were significant difference between 4 and 5 d after inoculation.The expression level of A7(Endo-S1-tag) was significantly lower than that of A9(HIV-ENV-S1-tag),the expression level of A4(Gp67-S1-tag) was the highest,and the secreted expression level of A1(Endo-Endo-Sl-tag) was significantly lower than that of A7(Endo-S1-tag).The secretion and expression of B6(HIV-ENV-RBD-tag) was signifi-cantly higher than that of B4(Gp67-RBD-tag) and other signal peptide groups,and C4(Gp67-RBD-dimer-tag) expression was significantly higher than that of C3(Gp64-RBD-dimer-tag).Two groups with high expression of each protein were selected separately for repeated verification(A4,A9;B4,B6;C3,C4) and the results showed that A4,B6 and C4 had the highest secretion expression levels.Conclusion The signal peptide for the highest secretion expression of S1 and RBD dimer proteins is the same,which is GP67 signal peptide,while the most suitable signal peptide for RBD protein is HIV-ENV,indicating that the N-terminal sequence can affect protein secretion,signal peptide sequence is universal to a certain extent,but is also related to the target protein sequence to be expressed.
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【Objective】 To construct the secretory expression system of insect cells to express the secretory TSHR A subunit protein in the ovarian cells of Spotoma oryzae (sf9). 【Methods】 A recombinant plasmid containing the target protein was constructed, and then the positive bacmid was screened out by the blue and white spots experiment. The verified bacmid was transfected into SF9 insect cells to obtain recombinant baculovirus. The virus was amplified, and the titer level was detected by virus plaque assay. Finally, Western blotting was used to identify the expression of the recombinant protein and optimize the expression conditions. 【Results】 During the construction of the protein expression system, PCR identification and sequencing results confirmed the correctness of the sequences of the recombinant plasmid and the recombinant bacmid. After the transfection of the bacmid, the signs of virus budding were observed in sf9 cells. The virus was collected and amplified. The titer of P1 generation virus was 2×107 pfu/m according to the plaque assay. The recombinant protein was identified by Western blotting and confirmed to be exogenous into the culture medium. The optimal condition for virus infection and protein expression was 72 h after the infection when the multiplicity of infection (MOI) was 1. 【Conclusion】 We constructed an insect cell expression system secreting TSHR 22-289 (55 ku), and the protein could be successfully glycolyzed. This system provides a preliminary basis for the construction and production of its industrial platform and also provides a useful tool for studies on TSHR protein and prevention of GO in the future.
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In the research and development of new drugs, it is very important to investigate the in vitro metabolism of candidate drugs. Traditional models such as liver microsomes have many limitations, while the in vitro model of recombinant human drug metabolizing enzymes is considered as an important and useful approach because of its convenient access, stable activity and low cost. In this study, six major human UDP-glucuronosyltransferases (UGTs) genes (UGT1A1, 1A3, 1A4, 1A6, 1A9 and 2B7) were cloned from human liver cDNA and heterologously expressed in Saccharomyces cerevisiae and baculovirus-infected insect cell. UGT1A1, 1A3, 1A6 and 1A9 were successfully expressed in yeast and showed glucuronidation activity against a variety of different structural types of substrates, but their activities were low. All six UGTs were successfully expressed and exhibited significantly improved glucuronidation activity when Trichopolusia ni cells BTI-TN5B1-4 (High Five) were used as the host. The recombinant human UGTs expressed in insect cells can catalyze the glucuronidation of their specific substrates, and the glucuronidation products were synthesized at milligram-scale with yields of 13%-66% for the first time, of which the structures were identified via MS, 1H NMR, and 13C NMR spectroscopic analysis. Above all, the recombinant human UGTs yeast and insect cell expression systems constructed in this study can be used for in vitro metabolism evaluation in the early stage of new drugs research and development, and also provide a new tool for the synthesis of glucuronide metabolites.
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Three insect cell lines, namely, DZNU-Bm-1, DZNU-Bm-12, and NIAS-MaBr-92, were tested for susceptibilityto Bombyx mori nucleopolyhedrovirus (BmNPV). The cytopathic effects of infection on cultured cells wereobserved. BmNPV was then serially passaged in these cell lines to assess their long-term ability to supportBmNPV replication. The cell lines were cultured in MGM-448 medium supplemented with 10% fetal bovineserum. Virus inoculum was prepared from B. mori larvae infected with BmNPV. The early signs of infectionstarted appearing within 16–36 hours post inoculation (hr pi). DZNU-Bm-1 and DZNU-Bm-12 cells showedheavy clumping. NIAS-MaBr-92 cells lost their motility and tended to form loose aggregations. Cytopathiceffects such as hypertrophy of nuclei and increase in cell size were prominent in all three cell lines. Beginningof occlusion body (OB) formation in DZNU-Bm-1 was first observed at about 36–42 hr pi, whereas, inDZNU-Bm-12, they were observed only after 42 hr pi. NIAS-MaBr-92 cells exhibited OB formation onlyafter 84 hr pi. The large mature OBs were visible in DZNU-Bm-1 cells by 66 hr pi, whereas, in DZNU-Bm-12cells by 72 hr pi. Mature OBs were observed in NIAS-MaBr-92 cells only after 120 hr pi. A number of OBsper cell varied from 12 to 82 in DZNU-Bm-1, 3 to 23 in DZNU-Bm-12, and 3 to 14 in NIAS-MaBr-92 cells.In this study, DZNU-Bm-1 and DZNU-Bm-12 cell lines were found to be better than NIAS-MaBr-92 interms of percentage infection. The yield of OBs per infected cell is also the highest in DZNU-Bm-1, whereasDZNU-Bm-12 and NIAS-MaBr-92 have comparable yields of OBs per cell.
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Mayaro virus (MAYV) is a mosquito-transmitted alphavirus that produces an acute, usually non-fatal, febrile illness including Mayaro fever. Like other alphaviruses, the MAYV E1 and E2 envelope glycoproteins are major viral surface antigens that play a key role in host recognition and infection. Here, we report expression and purification methods for recombinant MAYV E1 (rE1) and rE2 using a baculovirus system. Enzyme-linked immunosorbent assays (ELISA) revealed that rE1 and rE2 were antigenic and reacted with human anti-MAYV IgG and IgM. Cross-reactivity was also confirmed with human anti-Chikungunya virus (CHIKV) IgG and IgM. Furthermore, we developed an immunochromatographic strip test (IST) with rE2 to diagnose MAYV infection. Thus, purified rE2 may be valuable tool for rapidly diagnosing MAYV infection.
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Humans , Alphavirus , Antigens, Surface , Baculoviridae , Enzyme-Linked Immunosorbent Assay , Fever , Glycoproteins , Immunoglobulin G , Immunoglobulin MABSTRACT
PLCζ is a new isoenzyme of the PLC family which plays an important role in activating mammalian oocytes. In recent years, large-scale expression and purification of active PLCζ protein in vitro for structural biology research has not been successful. In this study, the recombinant human PLCζ protein was expressed and purified in the baculovirus expression system. First, the full length of human PLCζ gene was cloned into the pFastBac-HTA plasmid to form the recombinant donor plasmid that was further transformed into DH10Bac Escherichia coli cells to construct the recombined bacmid by the site-specific transposition that was screened by resistance and blue-white spots. Then the bacmid was transfected to Sf9 insect cells via cellfectin to package the recombinant baculovirus. After the amplification of the recombinant baculovirous, the recombinant protein was expressed from the cells transduced by the recombinant baculovirus and was purified by Ni-NTA resin. Purified protein was identified by Western blotting and time-of-flight mass spectrometry and the enzyme activity was determined. The results showed that the recombinant PLCζ protein in the Sf9 cells was achieved at 72 hours after baculovirus infection and expressed in secreted form in cell culture medium. The recombinant protein purified by Ni²⁺ affinity column was identified as PLCζ by Western blotting and ionization time-of-flight mass spectrometry and the enzyme activity was up to 326.8 U/mL. The experimental results provide a reference for the large-scale production and biological application of recombinant human PLCζ protein.
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Animals , Humans , Baculoviridae , Genetic Vectors , Recombinant Proteins , Sf9 Cells , SpodopteraABSTRACT
Baculovirus expression vector system (BEVS) has been successfully applied to the over-expression of various proteins, thus providing sufficient materials for vaccine research. Compared to other systems, BEVS has many advantages: baculovirus solely being parasitic in invertebrates, the resultant products conferring high safety to mammalian, high expression level of recombinant proteins, preferable folding for eukaryotic protein, proper post-translational modification required for biological function, suitable for multiple genes co-expression and large-scale production with serum-free culture media. To better understand the advantages and prospective of BEVS for the vaccine research, this article will review the development of BEVS and its application on vaccine research.
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Animals , Baculoviridae , Genetic Vectors , Prospective Studies , Recombinant Proteins , VaccinesABSTRACT
Objective:To construct I-Ad/IgG2b Fc baculovirus expression vector and express I-Ad/IgG2b Fc dimer fusion protein in Sf9 insect cells.Methods:I-Ad α,I-Ad β and IgG2b Fc gene sequences were amplified from BALB/c mouse lymphocytes by RT-PCR.I-Ad α and I-Ad β were connected with the leucine zipper sequence Fos and Jun respectively by overlapping PCR to form I-Ad α-Fos and I-Ad β-Jun.I-Ad α-Fos and IgG2b Fc fragments were ligated by restriction sites Xba I to form I-Ad α-Fos-IgG2b Fc recombination sequence.I-Ad α-Fos-IgG2b Fc and I-Ad β-Jun fragments were inserted to PPH and PP10,which were the downstream of the promoters in the plasmid pFastBacTMDual,to form pFastBacTMDual+[I-Ad/IgG2b Fc] recombinant plasmids.The constructed vector was identified by PCR,restriction endonuclease and sequencing.The recombinant plasmids pFastBacTMDual+[I-Ad/IgG2b Fc] was transferred into the DH10Bac competent cell to form recombinant baculovirus Bacmid+[I-Ad/IgG2b Fc].The recombinant baculovirus was transfected into Sf9 insect cells by liposome transfection reagent.After infected with Sf9 insect cells,the supernatant was collected and concentrated by PEG20000 to obtain I-Ad/IgG2b Fc dimer fusion protein.The fusion protein was detected by double-antibody sandwich ELISA and Western blot.Results:PCR,restriction enzyme digestion and sequencing confirmed that the recombinant vector pFastBacTMDual+[I-Ad/IgG2b Fc] had the correct sequence.The double antibody sandwich ELISA and Western blot showed that recombinant bacmid could successfully infect Sf9 insect cells,and the expressed fusion protein had the correct conformation.Conclusion:The pFastBacTMDual+[I-Ad/IgG2b Fc] baculovirus expression vector was successfully constructed and expressed in Sf9 insect cells,laying a foundation for the study of I-Ad-restricted T cells.
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Objective To establish an efficient baculovirus-insect cell expression system for the production of human immunodeficiency virus-1 ( HIV-1 ) envelope glycoprotein gp120 and to evaluate the physiochemical properties, antigenicity and immunogenicity of the recombinant protein. Methods The gene encoding HIV-1 NL4-3 gp120 was cloned into the downstream of pH promoter of the baculovirus transfer vec-tor pAcgp67B to construct the recombinant transfer vector pAc-gp120. Expression of the protein of interest was induced in baculovirus-infected High FiveTM insect cells. ELISA, analytical ultracentrifugation and size-exclusion chromatography were carried out to characterize physicochemical properties of the expressed gp120 protein. Immunogenicity of the recombinant gp120 protein was analyzed by HIV neutralization assay after im-munizing BALB/c mice with it. Results The recombinant HIV-1 gp120 protein was successfully obtained from the established insect cell expression system with a purity of more than 90％ and a mean yield of 13 mg/L in four batches. That recombinant HIV-1 gp120 protein was characterized by homogeneity in solution and possessed a good immunoreactivity to neutralizing antibodies and antisera against HIV. Immunogenicity analysis in BALB/c mice demonstrated that the recombinant gp120 protein could induce effective immune re-sponses against HIV-1 NL4-3. Conclusion A simple and scalable approach to obtain homogeneous and im-munogenic HIV-1 gp120 antigen is successfully established, which will promote further investigation of HIV vaccine candidates.
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Objective To establish an efficient baculovirus-insect cell expression system for the production of human immunodeficiency virus-1 ( HIV-1 ) envelope glycoprotein gp120 and to evaluate the physiochemical properties, antigenicity and immunogenicity of the recombinant protein. Methods The gene encoding HIV-1 NL4-3 gp120 was cloned into the downstream of pH promoter of the baculovirus transfer vec-tor pAcgp67B to construct the recombinant transfer vector pAc-gp120. Expression of the protein of interest was induced in baculovirus-infected High FiveTM insect cells. ELISA, analytical ultracentrifugation and size-exclusion chromatography were carried out to characterize physicochemical properties of the expressed gp120 protein. Immunogenicity of the recombinant gp120 protein was analyzed by HIV neutralization assay after im-munizing BALB/c mice with it. Results The recombinant HIV-1 gp120 protein was successfully obtained from the established insect cell expression system with a purity of more than 90％ and a mean yield of 13 mg/L in four batches. That recombinant HIV-1 gp120 protein was characterized by homogeneity in solution and possessed a good immunoreactivity to neutralizing antibodies and antisera against HIV. Immunogenicity analysis in BALB/c mice demonstrated that the recombinant gp120 protein could induce effective immune re-sponses against HIV-1 NL4-3. Conclusion A simple and scalable approach to obtain homogeneous and im-munogenic HIV-1 gp120 antigen is successfully established, which will promote further investigation of HIV vaccine candidates.
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Objective Production of autotoxin protein in sf9 insect cells with biological activity. Methods Autotaxin cDNA was cloned into pFastBacTMHTA from melanoma cell by extraction of total RNA using TRIzol method and RT-PCR. Bacmid-ATX is isolated from transformed competent bacterial DH10 which carries Bac genomic sequences and transfected into sf9 using lipofectamine 2000. Recombinant ATX virus was amplified in sf9 and further used for infection and expression of ATX protein. Two step purification product using HistrapTMHP and Hiload 16/600 Suerdex 200pg was determined for lysophospholipase D (lysoPLD) activity. Results Correct insertion of PCR fragment is confirmed by BamH I/Xho I digestion and sequencing. ATX virus can infect sf9 and induced enzymatic activity. Column purification and SDS-PAGE resulted 95% in purity and 6mg/liter in yield with significant lysoPLD activity. Conclusion ATX Baculovirus was successfully constructed that can infect sf9 cells and express active lysoPLD. Production of active ATX can be used for crystalography studies and screening for small pharmaceutical inhibitors.
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<p><b>Objective</b>To construct a GFP-fused mouse Parkin co-regulated gene (PACRG) baculovirus recombinant PACRG/GFP-pFastBac1 vector and express the fusion protein in Sf9 insect cells.</p><p><b>METHODS</b>Full-length mouse PACRG cDNA was amplified by PCR and cloned in frame to the vector pFastBac1 with eGFP (rpFBac-PACRG-GFP recombinant vector). The plasmid was transformed into DH10Bac cells to obtain the recombinant bacmid plasmid, the bacmid was transfected into Sf9 insect cells, and the expressed PACRG/GFP fusion protein was analyzed by Western blot and fluorescence microscopy.</p><p><b>RESULTS</b>The construction of the PACRG/GFP-pFastBac1 baculovirus plasmid was confirmed by sequencing and restriction enzyme digestion. Western blot showed the expression of the fusion protein carrying a green fluorescence in the Sf9 insect cells.</p><p><b>CONCLUSIONS</b>Conclusion: A PACRG/GFP-pFastBac1 recombinant baculovirus vector was successfully constructed and the fusion protein was highly expressed in the Sf9 insect cells. Our findings have provided a basis for further studies on the structure of the PACRG protein and regulation of spermatogenesis.</p>
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Animals , Mice , Baculoviridae , Blotting, Western , DNA, Complementary , Genetic Vectors , Green Fluorescent Proteins , Plasmids , Polymerase Chain Reaction , Proteins , Genetics , Metabolism , Recombinant Fusion Proteins , Sf9 Cells , TransfectionABSTRACT
The High Five cell line (BTI-TN-5B1-4) isolated from the cabbage looper, Trichoplusia ni is an insect cell line widely used for baculovirus-mediated recombinant protein expression. Despite its widespread application in industry and academic laboratories, the genomic background of this cell line remains unclear. Here we sequenced the transcriptome of High Five cells and assembled 25,234 transcripts. Codon usage analysis showed that High Five cells have a robust codon usage capacity and therefore suit for expressing proteins of both eukaryotic- and prokaryotic-origin. Genes involved in glycosylation were profiled in our study, providing guidance for engineering glycosylated proteins in the insect cells. We also predicted signal peptides for transcripts with high expression abundance in both High Five and Sf21 cell lines, and these results have important implications for optimizing the expression level of some secretory and membrane proteins.
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Animals , Amino Acid Sequence , Baculoviridae , Genetics , Codon , Gene Expression Profiling , Gene Expression Regulation , Glycosylation , Molecular Sequence Data , Protein Sorting Signals , Genetics , Recombinant Proteins , Genetics , Sf9 Cells , Spodoptera , GeneticsABSTRACT
Objective: To set up a baculovirus system for preparing recombinant adeno-associated virus serotype 8 (rAAV8) and to preliminarily examine the infection viability of the prepared virus in vitro. Methods: The rAAV8-EGFP was prepared using baculovirus system and was subsequently extracted and purified by high performance liquid chromatography. The viral titer was determined by real-time quantitative PCR and its infection viability for HEK-293 cells was examined by observing the EGFP reporter. Results: Real-time quantitative PCR showed that high titer of rAAV8-EGFP was prepared (1.5×10 13vg/bottle[100 ml medium]) and strong expression of EGFP was observed in HEK-293 cells infected with rAAV8-EGFP. Conclusion: The baculovirus system is capable of producing rAAV8 with high titer and infection viability, paving a way for future research.
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Lepidopteran heat-tolerant(ht)cell lines have been obtained with sf-9,sf-21 and several Bombyx cells.They have a distinct karyotype,membrane lipid composition,morphology and growth kinetics from the parental cell lines.In this paper,we report the development of ht cell lines from other insect species and examination of their growth characteristics and virus susceptibility.Adaptation of cell lines sf-9,BTI-TN-5131-4(High5)and BTI-TN-MG1(MG 1)to 33℃ and 35℃ was carried out by shifting the culture temperature between 28℃ and higher temperatures by a gradual stepwise increase in temperature.The process of adaption to a higher culture temperature was accomplished over a period of 2 months.The cell lines with the temperature adaption were designated as sf9-ht33,sf9-ht35,High5-ht33,High5-ht35,MG1-ht33,MG1-ht35.These cell lines have been subcultured over 70 passages.Adaption to high temperatures was confirmed by a constant population doubling time with individual cell lines.The population doubling time of heat adapted cell lines were 1-4 h less than these of parental cell lines.Cell shapes did not show obvious change,however,the cell size of sf9-ht cells was enlarged and those of High5 and MG1 ht cells were reduced after heat adaption.When the cell lines were infected with Autographa californica nuclear polyhedrosis virus(AcMNPV)at 28℃,33℃,35℃ and 37℃,production of budded virus and occlusion bodies in each cell line was optimum at its own adapted temperature.
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HBV polymerase has intrinsic RNA-dependent reverse transcriptase, DNA-dependent DNA polymerase as well as RNaseH activity. Analysis of HBV polymerase has been hampered for many years due to the inability to express functional enzyme in a recombinant system. To obtain active polymerase at a high level, we have taken advantage of baculovirus expression system. The gene of HBV polymerase was amplified by PCR and cloned into pFastBac Dual to construct the recombinant plasmid pFastbac Dual-pol. The recombinant donor plasmid, pFastbac Dual-pol, was constructed by inserting HBV polymerase gene into EcoRI and PstI sites controlled by polyhedrin promoter. The recombinant donor plasmid was transformed into DH10Bac competent cells for transposition. Recombinant bacmid was constructed by inserting of the mini-Tn7 element from the donor plasmid into the mini-attTn7 attachment site on the bacmid. The recombinant bacmid DNA was isolated and transfected into the Sf9 cells to produce the recombinant virus, and healthy insect Sf9 cells were infected with the recombinant virus containing HBV polymerse gene to express the target protein. HBV polymerse expressed in insect cells was analyzed by SDS-PAGE. PCR results showed recombinant donor plasmid, pFastbac Dual-pol, was constructed successfully. The recombinant hepatitis B virus polymerase was expressed in insect cells at high level. The recombinant hepatitis B virus polymerase should facilitate the analysis of HBV polymerase biological characteristics, allow the investigation for new anti-HBV drugs specifically blocking HBV polymerase.
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Objective To establish stable insect cell line expressing mIL4 on the basis of construction of inset expression vector pIZT/V5-His.Methods Amplified mIL-4 and pIZT/V5-His were treated with EcoRI and XbaI,and mIL-4 were ligated into pIZT/V5-His vector using T4 DNA ligase.Sf9 cells were transfected with recombinant DNA and ELISA was employed to detect soluble mIL-4 production by transfected Sf9 cells.Results Transfected Sf9 cells could significantly produce mIL4(1 mg?L~(-1)) compared!with control group(0.003 mg?L~(-1)).Conclusion Inset expression vector pIZT/V5-His is an ideal expression vector for mIL-4 production in transfected cells.
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Objective To construct baculovirus expression system for the human plasminogen kringle 5(hK5) gene,and detect its expression in Spodoptera frugiperda 21(sf21). Methods Baculovirus Bacmid-rhK5 was prepared with bac-to-bac baculovirus expression system,and sf21 cells were infected.The expression of rhK5 in sf21 cells was determined by Western blot.The activity of purified protein was detected by vascular endothelial cell inhibition test. Results The pFastBac HTB-rhK5 was successfully constructed,and sf21 cells were transfected with the constructed vector.The output of rhK5 obtained was 90 ug/L,and the protein possessed the inhibitory activity of endothelial cell proliferation.The median effective dose(ED50) was 4 ug/mL. Conclusion The rhK5 baculovirus expression vector is highly expressed in sf21 cells,which lays a foundation for the the expression of rhK5 protein with biologic activities.
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The baculovirus expression system has been used extensively for the expression of recombinant proteins in insect cells.Recently,recombinant baculoviruses containing mammalian cell-active promoter element have been used to transduce a broad spectrum of primary and established mammalian cells,including non-hepatic cells.Recombinant baculoviruses have been used successfully for transient or stable gene delivery in mammalian cells in vitro,while the efficiency of delivering gene in vivo is inhibited obviously by complements,but efforts have been made to overcome the problems,for instance,VSV-G-pseudotyped baculoviruses display complement resistance.The mechanism of the transduction is still not clearly understood,though many researches have been done.The baculovirus is able to replicate only in insect cells,but it is incapable of initiating replication cycle in mammalian cells,which guarantees high biosafety of this gene delivery system.In addition,this system is easily manipulated and able to carry large inserts.These attributes will undoubtedly lead to the increased application and continued development of this system for highly effective gene delivery into mammalian cells.
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Objective:Osteoprotegerin (OPG) is a key molecule negatively regulating osteoclast differentiation and activation; and the conserved mycobacterial heat shock 70 (HSP70) peptide p111-125 has also been found to inhibit inflammation reactions in chronic arthritis. BaculoDirectTM baculovirus expression system was selected to express recombinant OPG-HSP70 in insect cells.Methods:The human functional fragment (p22-194) of OPG and functional fragment (p111-125) of mycobacterial HSP70 gene were cloned into the transfer vector pENTRTM/SD/D-TOPO. The recombinant plasmid was performed an LR reaction with the BaculoDirectTM Linear DNA to generate recombinant baculovirus DNA. The cultured Sf9 insect cells were directly transferred with the recombinant baculovirus DNA,and the pure recombinant baculovirus was obtained. Then recombinant baculovirus was infected Sf9 insect cells again to express the OPG-HSP70 gene.Results:The target protein was detected at the time of 48h post infection,reached at highest yield at the time of 72h post-infection. A 28kDa protein immunostaining band was detected by Western blotting from lysate of those cells.And the purified protein was obtained by using Ni-NTA system. Functional stuies on the fusion protein showed it significantly reduce osteoclast cell number[(3.10?0.640) cells under each microscope field in treatment group by comparing to (10.70?0.817)cells in the control group] in the osteoclast inhibition test,and reduce the inflammation reaction in a delayed type hypersensitivity (DTH) mice model (P