The expression and purification of VP8* core protein of the rotavirus P 6 Genotype LL4260 / 中华实验和临床病毒学杂志

Objective@#The VP8* core protein of rotavirus P[6] genotype LL4260 was purified by prokaryotic expression, which is important for further study of protein structure and function.@*Methods@#The P[6] genotype LL4260 strain was obtained by PCR.The recombinant plasmid pET30 a-LL4260VP8*core was inserted into pET30 a vector and transformed into BL21 (DE3) competent cells with the correct recombinant plasmid. The expressed protein is purified by affinity chromatography and molecular sieve chromatography.@*Results@#The pET30 a-LL4260VP8* core region protein is soluble in the supernatant and proteins of approximately 22 kDa are identified by electrophoresis using purified proteins.@*Conclusions@#In this study, LL4260 containing pET30 a-LL4260VP8* core plasmid was successfully constructed and LL4260 strain VP8* protein was expressed.

Molecular cloning and prokaryotic expression of a type II ribosome inactivating protein from Polyporus umbellatus / 药学学报

A type Ⅱ ribosome inactivating protein (RIP) gene was cloned from Polyporus umbellatus sclerotia by RT-PCR method. The full open reading frame cDNA sequence of this gene was 873 bp in length and encoded a 290-aa protein with a molecular weight of 32.33 kDa and an isoelectric point of 5.58. Multiple sequence alignment revealed that the deduced amino acids possessed conserved domains of RICIN superfamily protein. A neighbor joining phylogenetic analysis suggests that PuRIP was closely related to RIP in Marasmius oreades. Real time PCR results showed that this gene expressed in all tested tissues of P. umbellatus. Meanwhile, the expression of this gene was significantly up-regulated in the part infected by Armillaria mellea. This result suggested that this PuRIP might played important role with potential biotic stress tolerance of P. umbellatus. Otherwise, we successfully constructed the pET15b-PuRIP plasmid, produced and purified the His-PuRIP fusion protein, which would provide the basic material for polyclonal antibody preparation and gene function research.

Development of the high-throughput screening fluorescence polarization assay for HSP90 inhibitor / 中国生化药物杂志

Objective To establish the high-throughput screening fluorescence polarization assay for HSP90 inhibitor.Methods E.coli strain BL21 ( DE3) competent cells were transformed with pET24α( +)-HSP90αplasmid.The cell lysate supernatant was induced to product the soluble protein and purified with Ni-NTA agarose.Western blot analysis was used to identify whether the purified protein is HSP90α.The fluorescence polarization assay for screening HSP90 inhibitors was established and optimized using varying concentrations of recombinant HSP90 protein and molecular probe VER00051001.Meanwhile, the binding activity of GA and NVP-AUY922 for HSP90αwas measured by fluorescence polarization assay.Results HSP90αwas induced expression and purified successfully.The fluorescence polarization assay was performed using 80 nM probe VER00051001 and 2.01μg/mL HSP90α, with the Z factor of 0.83.GA and NVP-AUY922 competed with the probes VER00051001 for binding sites of HSP90, with IC50 of 55 nM and 13 nM, respectively.Conclusion A reliable model was established using fluorescence polarization assay for screening HSP90 inhibitors.

Expression and purification of a jasmonic acid carboxyl methyltransferase from Salvia miltiorrhiza in E.coli / 药学学报

Jasmonic acid carboxyl methyltransferase (JMT), a key enzyme for jasmonate (JA) biosynthesis, catalyzes the methylation of JA to form MeJA. To characterize the function of JMT, a plasmid pGEX-4T-SmJMT1 harboring JMT1 (SmJMT1) gene from Salvia miltiorrhiza was successfully transformed into E.coli BL21 (DE3) for protein expression. The recombination SmJMT1 was separated using SDS-PAGE and the size of expressed SmJMT1 protein was consistent with the prediction. The bacterial growth conditions were determined for optimal expression, which include growth temperature, incubation time, IPTG concentrations and culture density. The optimal growth conditions for SmJMT1 were that the bacterial cultures were grown to an A600 of 0.8, and induced with IPTG at a final concentration of 0.4 mmol·L-1, and then incubated for 8 h at 20℃. The expression of SmJMT1 in E.coli was confirmed by Western blotting, and mass spectrometry analysis of methyltransferase family. The successful expression and purification of JMT in this study provide the basis for more study of JA biosynthetic pathway and JA-regulated secondary metabolism of medicinal plants.

Prokaryotic expression and purification of Aquilaria sinensis (Lour.) Gilg AsMYC2 protein / 药学学报

The MYC2 transcription factor is a member of the important plant bHLH transcription factor families, and it is also the core regulatory elements in jasmonate (JA) signaling pathway. However, there is a little information about AsMYC2 gene in Aquilaria sinensis. In this study, with the total RNA isolated from A. sinensis leave as template, the full-length coding sequence (CDS) of AsMYC2 gene was amplified using RT-PCR method and subcloned into pGEX-4T-1 vector by the gene recombination technique. The recombinant vector pGEX-4T-1-AsMYC2 was verified by restriction enzyme digestion and nucleotide sequencing, and was transformed into E. coli BL21(DE3) to express the protein. A maximum expression of soluble protein was observed with induction by 0.1 mmol·L-1 IPTG at 37℃ for 4 hours. The fusion protein was purified through a Sepharose-Glutathione column, and verified by SDS-PAGE and Western blotting using an anti-GST polyclonal antibody. We successfully constructed the GST-AsMYC2 plasmid, produced and purified the GST-AsMYC2 fusion protein, which would provide the basic material for polyclonal antibody preparation, interactive factors screening and gene function research. According to the tissue-specific expression pattern analysis by qRT-PCR method, the AsMYC2 gene in A. sinensis tissues is mainly expressed in roots and stems, the main agarwood formation parts, and lowest expressed in leaves. These results indicate that AsMYC2 gene likely play some roles in agarwood formation in A. sinensis.

Cloning and expression of MICB gene and its application for the detection of anti-MICB antibodies / 中华微生物学和免疫学杂志

Objective To construct a prokaryotic expression system for major histocompatibility complex class Ⅰ chain-related gene B ( MICB) and to establish an ELISA method for the detection of anti-MICB antibodies in patients with kidney transplantation. Methods The MICB cDNA fragments were ob-tained by RT-PCR with a pair of specific primers. The MICB cDNA and the prokaryotic expression vector pET-28a were digested by two restriction enzymes and ligated to construct the recombinant expression plas-mid pET-28a-MICB. The transformed E. coli BL21 DE3 strains carrying recombinant expression plasmid were induced by IPTG to express MICB protein. The expressed recombinant proteins were identified by Western blot assay and purified by Ni-NTA Spin column. The purified proteins were coupled to ELISA for the detection of anti-MICB antibodies in patients with kidney transplantation. Results Three common MICB fragments contained the exons 2 and 3 were obtained. The recombinant proteins were expressed in E. coli BL21 DE3 strains carrying pET-28a-MICB and successfully purified by the Ni-NTA Spin column. Results of the Western blot assay confirmed that the obtained proteins were the target proteins. The ELISA method was successfully established and used for the detection of anti-MICB antibodies in 24 patients with kidney trans-plantation. The absorbance values indicated that the sensitivities of three recombinant MICB proteins were different. Conclusion The expression system for MICB gene was successfully constructed. The established ELISA for the detection of anti-MICB antibodies would pave the way for further investigation on the correla-tions between MICB protein and transplantation immunity.

Preparation and identification of monoclonal antibody against human SUMO1 / 基础医学与临床

Objective To express the human recombinant SUMO1 protein and prepare monoclonal antibody(mAb) against it.Methods The recombinant expression plasmid pET32a-HIS-SUMO1 was made and transformed into E.coli(BL21),then the recombinant fusion protein HIS-SUMO1 was expressed and purified.The BALB/c mice were immuned with pure protein HIS-SUMO1 as antigen.Monoclonal antibody against SUMO1 was prepared with standard hybridoma technology.The hybridoma cell lines were obtained by ELISA and Western blot screening procedure,the isotype of the mAbs were further identified by immune-double diffusion.Ascites were collected from one propagated hybridoma cell line and mAbs were purified by using the Kit of Millipore.The valence of mAb was detected by Western Blot.Results The recombinant protein HIS-SUMO1 is expressed and purified.Three hybfidmas producing antibodies against SUMO1 were obtained,the isotypes of three mAbs are IgG1,Western blot showed that the antibodies were specific for SUMO1.The antibody purified from the ascites has better specificity.Conclusion The SUMO1 mAb prepared by using recombinant SUMO1 protein as antigen can be used for detectingthe protein sumoylation.

Expression and Purification of the Capsid Protein of the Japanese Encephalitis Virus and Production of its Polyclonal Antibody

Japanese encephalitis virus (JEV) is a member of Flaviviruses, transmitted by mosquitoes. The core of JEV is composed of the capsid (C) proteins. In order to produce the recombinant viral C protein and the antiserum specifically recognizing the JEV C protein, we have expressed and purified the JEV C protein as a Glutathion-S-Transferase (GST) fusion protein in E. coli. The JEV C protein-coding region was PCR-amplified using the infectious cDNA of a JEV Korean isolate, and the amplicons were cloned into the pGEX4T-1 E. coli expression vector. GST-C fusion proteins were purified using a glutathione sepharose column. Subsequently, the GST-C fusion proteins were used for immunization of rabbits, and the antisera were obtained from those immunized animals. Western blot analysis using the JEV-infected BHK21 cell lysates showed that these antisera specifically reacted with the JEV C proteins. This study will provide a useful reagent for the diagnosis and understanding of the viral morphogenesis in the JEV-infected cells.

Immunogenicity of N-terminal 158 amino acid motif of E-protein of a newly purified mutant dengue virus from a Chinese patient / 中国免疫学杂志

Objective:The envelope protein Domain I(DI) of type II mutated dengue virus from a DHF patient (B-E) was expressed,refolded and purified.Its immunogenicity was also identified.Methods:The 1-476 bp of B-E was cloned into pET28a(+),and it was transformed into E.coli after digestion and sequencing.The inclusion body was denatured and refolded after inducing with IPTG.Polyclone antibody was obtained by immunizing C57BL/6 and BALB/c mice with purified B-E,and identified with Western blot and ELISA.Results:The cDNA of B-E gene was inserted into pET28a(+) vector and transformed into Rosetta(DE3).The protein of B-E was mainly in inclusion body and the molecular weight was 20 kD as predicted.Western blot was used to identify the recommend protein with anti-his antibody.The soluble recombination protein was purified after denaturation and refolding.The polyclonal antibody was obtained by immunizing BALB/c and C57BL/6 mice and could be used in Western blot and ELISA assay.The titer of polyclonal antibody from C57BL/6 was 1:12 800 through ELISA assay,and titer of polyclonal antibody from BALB/c was 1:500 through Western blot.Conclusion:All the results suggests that B-E is immunogenic in BALB/c and C57BL/6 mice.

Expression,purification and preparation of monoclonal antibody of HCA518 protein / 中国免疫学杂志

Objective; To express and purify HCA518 protein and prepare its monoclonal antibody ( McAb). Methods: The HCA518 protein was expressed with gene recombinant technique in prokaryotic system and purified with nickel chelate nitrilotriacetic acid(Ni-NTA) affinity chromatography column. Hybridoma cell lines that secreted anti-HCA518 McAb were established by cells fusion and screened by enzyme linked immunosorbent assay( ELISA). The specificity of anti-HCA518 McAb wa3 identified by Western blot assay. The HCA518 protein in tumor cells was stained by immunoflourescence assay. Results: Rcombinant HCA518 protein was expressed with a purity of 98%. Two hybridoma cell lines was selected and anti-HCA518 McAb was purified from mice ascites. The titers of anti HCA518 McAb in ascites were 1?10-4 and 5?10-4 respectively. The antibody belonged to IgG2b subtype and IgM. Anti-HCA518 McAb specifically reacted with recombinant HCA518 protein and tumor cells'nuclear protein (P100). The HCA518 protein was mainly located in cell nucleus. Conclusion: Stable hybridoma cell lines that secreted anti-HCA518 McAb have been established and anti HCA518 McAb was prepared with high specificity. It has important significance for detecting HCA518 protein in tumor tissues and determining malignant proliferation status of tumor cells and predicting its prognosis.