O型口蹄疫病毒OA58株3C基因的克隆与真核表达

利用RT-PCR技术扩增获得了长度约640 bp的口蹄疫病毒目的基因,回收片段后与pMD18-T载体进行连接,测序结果表明获得了口蹄疫病毒3C基因。将重组质粒pMD18-3C与表达载体pEGFP-N1分别用BamHⅠ+XhoⅠ双酶切后,进行定向亚克隆,对重组表达质粒pEGFP-3C进行PCR、酶切鉴定及DNA测序,结果表明重组表达质粒所含的3C基因读码框正确。用pEGFP-3C转染BHK-21细胞,荧光显示目的基因EGFP发出绿色荧光;对3C转录的mRNA进行RT-PCR鉴定,证实3C基因在BHK-21细胞中得到了表达。

人pot1基因cDNA的克隆及其在HeLa细胞中的表达

目的:克隆人端粒保护蛋白(hum an protection of telom eres 1,p ot1)基因cDNA全编码区,构建成真核表达质粒并实现在H eL a细胞中的表达。方法:RT-PCR法扩增出H eL a细胞hp ot1基因cDNA编码区全序列,定向克隆至真核表达载体pcDNA 3,阳性重组质粒经插入片段测序验证;重组的pcDNA 3-hp ot1质粒瞬时转染H eL a细胞,RT-PCR和EM SA法(电泳迁移率改变分析)检测hp ot1基因的表达水平。结果:来自H ela细胞的hp ot1基因cDNA编码区全序列构建成的真核表达质粒pcDNA 3-hp ot1,经测序分析序列和ORF正确;该重组质粒转染在H eL a细胞48h后,hp ot1基因表达水平增高。结论:真核表达载体pcDNA 3-hp ot1构建成功,并实现了hp ot1在H ela细胞中的表达。

Construction and Preliminary Identification of Eukaryotic Expression Vector of Cryptosporidium parvum miR-2980

[Objective] This study aimed to construct and preliminarily identify the eu- karyotic expression vector of Cryptosporidium parvum miR-2980. [Method] The cp-miR- 2980 precursor was amplified from C. parvum genomic DNA and cloned into pMD18- T vector. The amplified precursor was then subcloned into pVAX I vector and identi- fied with restriction endonuclease digestion and sequencing. The recombinant plasmid pVAX-miR2980 was transfected into HCT-8 cells. Total RNA was extracted and the expression of cp-miR-2980 was evaluated by RT-PCR detection. [Result] The results showed that the recombinant eukaryotic expression vector pVAX-miR2980 was suc- cessfully constructed, which can express cp-miR-2980 in HCT-8 cell. [Conclusion] This study laid the foundation for further exploring the biological function of cp-miR-2980.

Establishment of BHK-21 Stable Cell Lines Expressing T7 RNAP and GFP

[Objective] The aim was to establish the BHK-21 stable cell lines expressing T7 RNAP and GFP.[Method]T7 RNAP gene was amplified from E.coli BL21（DE3）and inserted into FG12 vector.The lenti-virus recombinant plasmid FG12-T7 RNAP plasmid was obtained via identification with double enzymes digestion and gene sequencing.The transient expressed T7 RNAP protein was determined by WB in 293T cells transfected with FG12-T7 RNAP plasmid.The recombinant FG12-RNAP lenti-virus was packaged up by transfecting the 293 cells with the recombinant vector FG12-RNAP and the helper plasmids via lipofectamine-2000,which was then used to infect BHK-21 cells.The positive cell clones were obtained after continuous screening by GFP.The expression of T7 RNAP gene was confirmed by Western blot.[Result]The cell line stably expressing the T7 RNAP gene was established by Western blot.[Conclusion]T7 RNAP gene could be stably expressed in eukaryotic cells and it provided a good platform to rescue RNA virus in vivo.

Construction of Eukaryotic Expression Vector with Partial Encoding Sequence of Actin from Cryptosporidium andersoni

[Objective] To clone the actin gene of Cryptosporidium andersoni, and to study its eukaryotic expression in Hela cells. [Methed] Specific primers were designed for the partial encoding sequence of actin, which were obtained by screening the T7 phage display library of Cryptosporidium andersoni, and the actin gene CA42 was amplified by PCR. Recombinant eukaryotic expression plasmid pVAX1-CA42 was constructed and transfected to Hela cells with lipofection strategy. Indirect im- munofluorescence staining, SDS-PAGE and Western blotting analysis were used to detect the expression of recombinant protein in Hela cells. [Result] CA42 protein was successfully expressed in Hela cells, and the expression products had reactogenicity. [Conclusion] The partial encoding sequence of actin from Cryptosporidium andersoni has been successfully cloned, and it can be stably expressed in Hela Cells

Construction and Characterization of an Antisense RNA Eukaryotic Expression Vector for Survivin

Objective: To inhibit specifically survivin expression and block its function in leukemia cells, an antisense RNA expression plasmid for survivin was constructed and transfected into a leukemia cell line.Methods: A cDNA fragment of survivin obtained by RT-PCR was inserted into a plasmid vector named pcDNA3 in the reverse direction. Antisense RNA of survivin was confirmed by restriction enzyme digestion and DNA sequencing. The recombinant plasmid was transfected into the cell line HL-60 by electroporation. The effect of survivin antisense RNA on survivin mRNA expression in transfected cells was examined by RT-PCR.Results: The correct construction of the recombinant plasmid has been shown by restriction enzyme digestion and DNA sequencing. As compared to controls, the level of survivin mRNA expression in transfected cells decreased significantly.Conclusion: An antisense RNA vector for survivin has been successfully constructed and may be useful as a specific inhibitor in leukemia cells. Thus, antisense therapy on the basis of survivin can be further explored in leukemia. Key words leukemia - survivin - antisense RNA This project was supported by a grant from National Key Basis Research Program of China (No. CB 513109) and the National Natural Sciences Foundation of China (No. 39970693).

Expression and Purification of Arabidopsis High Mobility Group B Protein Gene At2G34450 in Pichia pastoris

[Objective] The aim was to study the expression of Arabidopsis gene A/2G34450 in Pichia pastoris and to obtain recombinant Arabidopsis HMGB protein. [Method] The At2G34450 gene was cloned into yeast expression vector pPIC9K containing AOXl promoter and the sequences of secreting α-signal peptides. Recombinant plasmid was linearized by Sal l and transformed into P. pastoris GSl15 competent cells by electroporation. Positive integrated clones were screened out, and the At2G34450 protein was expressed under the induction of methanol. [Result] The At2G34450 protein was expressed in yeast medium through methanol induction. SDS-PAGE results showed that recombination product was At2G34450 protein. [Conclusion] At2G34450 protein was successfully expressed in the P. pastoris system for the first time, which paves a direct path to further research on the functions of HMGB family members.

Construction of Eukaryotic Expression Vector for Pig Ghrelin Gene

[Objective] This study aimed to investigate the functions of transgenic growth related gene in pig growth. [Method] A pair of primers containing Nhe I and Hind Ⅲ restriction sites were designed by referring to the pig Ghrelin mRNA sequence published in Genbank. Total RNA was extracted from the small intestine tissue of 13/17 Robertson translocation heterozygous pig, and then was purified and used as the template in later RT-PCR reaction to amplify the full-length pig Ghrelin gene. The correct pig Ghrelin gene fragment was cloned into the pMD19-T simple vector for sequencing analysis. The obtained full-length cDNA of pig Ghrelin gene fragment was digested with both Nhe I and Hind Ⅲ, and then was linked into the eukaryotic expression vector pEGFP-N1 to obtain the recombinant plasmid pEGFPGhrelin. The recombinant plasmid was transected into the fibroblast cells to detect the fluorescence labeled gene expression. [Result] The nucleotide sequence extracted from 13/17 Robertson translocation heterozygous pig was the same as expected; and the eukaryotic expression vector pEGFP-Ghrelin was successfully constructed. [Conclusion] The eukaryotic expression vector constructed in this study can be further used in research on transgenic pigs, but also lays foundation for research on the regulatory mechanism of Ghrelin gene.

Cloning and Functional Analysis of the Full Length cDNA Sequence of Eukaryotic Translation Initiation Factor 5 in Schistosoma japonicum

The expressed sequence tag of eukaryotic translation initiation factor 5 （eIF5） from the Schistosoma japonicum adult worm cDNA library through subtractive hybridization between male and female worms was analyzed by the bioinformatics method. The overlapping sequences were assembled into one that includes the complete open reading frame （GenBank accession number： AY686501）. The full-length cDNA of SjeIF5 was cloned into a pET-28c^（＋） vector, which generated a prokaryotic expression plasmid, and a fusion protein of 18 kDa was induced in Escherichia coll. The recombinant expression of eIF5 protein of Schistosoma japonicum was purified. The immunoprotection test against schistosomiasis demonstrated that the recombinant protein worked to a certain extent, especially in the reduction of eggs in the liver of the host.

禽流感病毒(H9亚型)重组CHO细胞258株的构建及鉴定

为构建禽流感病毒(AIV)重组CHO细胞株,本研究以AIV(H9亚型)258株为模板,以AIV的HA基因胞外域及3个重复串联的M2蛋白胞外域为靶基因,根据CHO细胞密码子偏爱性对其密码子进行优化,将HAM2e基因插入真核表达载体pCI-GS中,构建了含有HA-M2e基因的重组质粒,并将该重组质粒转染CHO细胞,经加压筛选获得了高效表达HA-M2e蛋白的重组CHO细胞株。采用十二烷基硫酸钠聚丙烯酰胺凝胶电泳(SDSPAGE)和蛋白质免疫印迹(Western Blot)法对重组CHO细胞株进行鉴定,并用琼扩试验及酶联免疫吸附试验(ELISA)对表达蛋白进行效价及蛋白含量测定。结果显示,经SDS-PAGE、Western Blot检测,表达蛋白大小约66 ku,与预期大小相符;琼扩效价为1􀏑512,蛋白质含量为1.13 mg·mL^(-1)。表明通过基因工程技术构建的含AIV HA-Mze基因的重组CHO细胞258株可作为疫苗研制用毒株。

Cloning and Expression Analysis of a Human Putative Tumor Suppressor Gene Homologue from Rice

A gene homologous to the human Putative tumor suppressor gone QM, designated OSQM1, was isolated from rice (Oryza sativa L.) genomic DNA library using through homology screening. It contained 4 exons and 3 introns, encoding a protein of 219 amino acids with 46 basic amino acids, leading to a high isoelectric point of 11.02. Homology search showed that this gene existed in eukaryotes and highly conserved throughout eukaryotes, suggesting an essential role of this gene. Northern Not analysis showed that it was expressed in various rice organs, but at lower level in developing flower and callus tissue than in other vegetative organs. Its expression levels in roots and leaves were influenced by different environmental factors.

Construction of RNAi Vector Which Resist Cucumber Mosaic Virus and Transformation of Tobacco

[Objective] Aimed to construct RNAi vector resistant to cucumber mosaic virus and transferred this vector into tobacco. [Method] RT-PCR method was used to amplify cucumber mosaic virus NS04 and process RNA2 gene sequen of tomato isolates. The analysis results of phylogenetic tree demonstrated that the sequence in RNA2 encoded CMV-2a had 98.0% and 96.5% homology with nucleotide and amino acid of DQ412731 isolate of Zhejiang,China. The replicase fragment in CMV RAN2 gene was taken as target sequence to construct pBi35SCR2 eukaryotic expression vector,then the expression vector was identified. Through agrobacterium-mediated method,the expression vector was transferred into tabacco and PCR method was used to check the transfer. The PCR results demonstrated that the experiment had successfully construct eukaryotic expression vector of pBi35SCR2 and the expression vector was successfully transferred into tabacco. [Conclusion] The obtained transgenic tobacco could be used as challenge test material in following experiment and provided foundation for studying processing tomato resist cucumber mosaic virus.

Effect of NHE1 antisense gene transfection on the biological behavior of SGC-7901 human gastric carcinoma cells

AIM: To study the effect of type 1 Na+/H+ exchanger (NHE1 ) antisense human gene transfection on the biological behavior of gastric carcinoma cell line SGC-7901. METHODS: Antisense NHE1 eukaryotic expression on vector pcDNA3.1 was constructed by recombinant DNA technique and transfected into gastric carcinoma cell line SGC-7901 with DOTAP liposome transfection method. Morphological changes of cells were observed with optic and electron microscopes. Changes in cell proliferative capacity, apoptosis, intracellular pH (pHi), cell cycle, clone formation in two-layer soft agar, and tumorigenicity in nude mice were examined. RESULTS: Antisense eukaryotic expressing vectors were successfully constructed and transfected into SGC-7901. The transfectant obtained named 7901 -antisense (7901-AS) stablely produced antisense NHE1. There was a significant difference between the pHi of 7901-AS cells (6.77 ± 0.05) and that of 7901-zeo cells and SGC-7901 cells (7.24 ± 0.03 and 7.26 ± 0.03, P < 0.01). Compared with SGC-7901 and 7901-zeo cells, 7901-AS cells mostly showed cell proliferation inhibition, G1/G0 phase arrest, increased cell apoptotic rate, recovery of contact inhibition, and density contact. The tumorigenicity in nude mice and cloning efficiency in the two-layer soft agar were clearly inhibited. CONCLUSION: NHE1 antisense gene significantly restrains the malignant behavior of human gastric carcinoma cells, suppresses cell growth and induces cell apoptosis, and partially reverses the malignant phenotypes of SGC-7901 . These results suggest a potential role for human tumor gene therapy.

Effect of naked eukaryotic expression plasmid encoding rat augmenter of liver regeneration on acute hepatic injury and hepatic failure in rats

AIM: To study the protective effect of eukaryotic expression plasmid encoding augmenter of liver regeneration (ALR) on acute hepatic injury and hepatic failure in rats. METHODS: The PCR-amplified ALR gene was recombined with pcDNA3 plasmid, and used to treat rats with acute hepatic injury. The rats with acute hepatic injury induced by intraperitoneal injection of 2 mL/kg 50% carbon tetrachloride (CCl4) were randomly divided into saline control group and recombinant pcDNA3-ALR plasmid treatment groups. Recombinant pcDNA3-ALR plasmid DNA (50 or 200 μg/kg) was injected into the rats with acute hepatic injury intravenously, intraperitoneally, or intravenously and intraperitoneally in combination 4 h after CCl4 administration, respectively. The recombinant plasmid was injected once per 12 h into all treatment groups four times, and the rats were decapitated 12 h after the last injection. Hepatic histopathological alterations were observed after HE staining, the expression of proliferating cell nuclear antigen (PCNA) in liver tissue was detected by immunohistochemical staining, and the level of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) was determined by biochemical method. The recombinant plasmid DNA (200 μg/kg) and saline were intraperitoneally injected into the rats with acute hepatic failure induced by intraperitoneal injection of 4 mL/kg 50% CCl4 after 4 h of CCl4 administration, respectively. Rats living over 96 h were considered as survivals.RESULTS: The sequence of ALR cDNA of recombinant pcDNA3-ALR plasmid was accordant with the reported sequence of rat ALR cDNA. After the rats with acute hepatic injury were treated with recombinant pcDNA3-ALR plasmid, the degree of liver histopathological injury markedly decreased. The pathologic liver tissues, in which hepatic degeneration and necrosis of a small amount of hepatocytes and a large amount of infiltrating inflammatory cells were observed, and they became basically normal in the most effective group after four times of injection of recombinant pcDNA3-ALR plasmid. The indexes of PCNA significantly increased in the recombinant pcDNA3-ALR plasmid treatment groups compared to model group. The level of serum AST and ALT remarkably reduced in recombinant pcDNA3-ALR plasmid treatment groups compared to model group. The results showed that the effect of 200 μg/kg recombinant pcDNA3-ALR plasmid in the rats with acute liver injury was stronger than that of 50μg/kg pcDNA3-ALR DNA.The effect of intravenous injection of recombinant pcDNA3ALR plasmid was better. After the rats with acute hepatic failure were treated with recombinant pcDNA3-ALR plasmid,the survival rate (40%) significantly increased in treatment groups compared to control group (15%, P＜0.01).CONCLUSION: The ALR gene may play an important role in relieving acute hepatic injury and hepatic failure by promoting hepatic cell proliferation and reducing level ofAST and ALT in CCl4-intoxicated rats.

High expression of osteoglycin decreases gelatinase activity of murine hepatocarcinoma Hca-F cells

AIM:To investigate the possible correlation between osteoglycin expression and gelatinase activity of mouse hepatocarcinoma Hca-F cells.METHODS:A eukaryotic expression plasmid pIRE Spuro3 osteoglycin(+)was constructed and transfected into Hca-F cells to investigate the possible correlation between osteoglycin expression and gelatinase activity of Hca-F cells cultured with extract of lymph node,liver,spleen or in DMEM medium.The activity of gelatinases was examined through zymographic analysis.RESULTS:High expression of osteoglycin attenuated the gelatinase activity of Hca-F cells cultured with extract of lymph node,and at the same time,decreased the metastatic potential of Hca-F cells to peripheral lymph nodes in vivo.CONCLUSION:High expression of osteoglycin decreases the gelatinase activity of Hca-F cells cultured with extract of lymph node;regulation of gelatinase activity might be one of mechanisms that osteoglycin contributes to lymphatic metastasis suppression.

Expression and Purification of Enterovirus Type 71 Polyprotein P1 using Pichia pastoris system

Enterovirus type 71（EV71） causes severe hand-foot-and-mouth disease （HFMD） resulting in hundreds of deaths of children every year; However, currently, there is no effective treatment for EV71. In this study, the EV71 poly-protein （EV71-P1 protein） gene was processed and cloned into the eukaryotic expression vector pPIC9k and then expressed in Pichia pastoris strain GSll5. The EV71 P1 protein with a molecular weight of 100 kD was produced and secreted into the medium. The soluble EV71 P1 protein was purified by column chromatography with a recovery efficiency of 70%. The result of the immunological analysis showed that the EV71 P1 protein had excellent immunogenicity and could stimulate the production of EV71-VP1 IgG antibody in injected rabbits. We suggest that EV71-P1 protein is an ideal candidate for an EV71 vaccine to prevent EV71 infection.

Effects of HMGB1 Expression Suppressed by siRNA on Cell Cycle and Proliferation of Human Cervical Cancer Cell Line HeLa

OBJECTIVE In this study, RNA interference was used to evaluate the effects of HMGB1 expression on cell cycle and proliferation of the human cervical cancer cell line HeLa.METHODS We had previously constructed and screened effective eukaryotic expression vectors carrying PGCsi3.0-1/ HMGB1 siRNA and PGCsi3.0-3/HMGB1 siRNA, then the vectors were transfected into HeLa cells. The expression of HMGB1 before and after transfection in HeLa cells were detected by RT-PCR and Western blot. The cell viability and proliferating activity was tested by Trypan blue dye test and MTT, and the cell cycle was determined bv flow cvtometry.RESULTS The introduction of PGCsi3.0-1/HMGB1 siRNA and PGCsi3.0-3/HMGB1 siRNA inhibited the expression of HMGB1 mRNA and protein efficiently and specifically, there was a significant difference between the siRNA groups and the control groups （P 〈 0.05）. The proliferation speed of PGCsi3.0-1 group and PGC si3.0-3 group were obviously slower than those of PGCsi3.0- Neg group and non-transfected group. Flow cytometry showed that the content of DNA in G2 phase in PGCsi3.0-1 group and PGCsi3.0-3 group were obviously more than those in PGCsi3.0- Neg group and non-transfected group, but the content in S phase was less （P 〈 0.01）. The progression of cell cycle was arrested from G2 to S phase.CONCLUSION PGCsi3.0-1/HMGB1 siRNA and PGCsi3.0-3 /HMGB1 siRNA could specially suppress the expression of HMGB1 gene, inhibit the proliferation speed of HeLa cells effectively, and arrest the progression of cell cycle from G2 to S phase. RNAi provides a new approach to the bio-therapy of cervical cancer.

Construction of eukaryotic expression vector carrying human TSLC1 gene and its expression in HepG2 cells

Objective： To construct the eukaryotic expression vector for human TSLC1 gene, and to express TSLC1 in HepG2 cells for investigating its effect on HepG2 cell growth. Methods： Full length of TSLC1 cDNA was amplified from RNA of normal human liver by RT-PCR, and cloned into pCI-neo expression vector. The recombinant plasmid pCI-TSLC1 was identified with restriction enzyme and sequenced, and then was stably transfected into HepG2 cells with lipofectamine 2000. The positive clones were examined by western-blotting and immunofluorescence, cell growth was analyzed with MTT assay. Results： The eukaryotic expression vector pCI-TSLC1 was successfully constructed and the stable cell line highly expressing TSLC1 protein was obtained. The growth of TSLCl-transfected cells was significantly suppressed in vitro. Conclusion： The HepG2 stable cell line could highly express TSLC1 protein, which provided a basis for further exploring the roles of TSLC1 in hepatocellular carcinoma.

Construction of recombinant plasmid pEGFP-C2-L539fs/47 and its expression in HEK293 cells

Objective:To reconstruct pEGFP-C2-L539fs/47,a HERG nonsense mutant in eukaryotic expression plasmid,and observe the fusion protein expressed in HEK293 cells(human embryo kidney cells).Methods:After double digestion of pcDNA3-L539fs/47 and pEGFP-C2-HERG with sbf I and Eco91 I,the small product fragment,from pcDNA3-L539fs/47,was subcloned into the big fragment of pEGFP-C2-HERG under T4 ligase.pEGFP-C2-L539fs/47 was identified by agarose gel electrophoresis and sequencing.pcDNA3-L539fs/47 and pEGFP-C2-L539fs/47 were transiently transfected into HEK293 cells by Lipofect,respectively.The expression of fusion protein in HEK293 cells was detected through immunofluorescence,laser confocal imaging scanning in vivo,Western blot and PCR.Results:Mutation region cDNA fragment(about 1 kb) and target vector fragment(about 7.2 kb) were ligated after purification and gel recovery.Agarose gel electrophoresis and sequencing successfully demonstrated eukaryotic expression plasmid pEGFP-C2-L539fs/47,constructed approximately 8.2 kb,sequencing consistent with template gene.The transfection efficiency of recombinant plasmid by fluorescence microscopy was more than60%.Western blot analysis detected pcDNA3-L539fs/47 expression of the protein size 60 KD,the expression of pEGFP-C2 fusion protein size of approximately 90 KD.The L539fs/47 gene expression in HEK293 cells was significant by PCR analysis.Confocal laser imaging showed that pEGFP-C2-L539fs/47 protein was successfully expressed in cytoplasm and cytomembrane of HEK293 cells.Conclusion:pEGFP-C2-L539fs/47 containing the HERG gene mutant was successfully constructed by double digestion method and expressed fusion protein in HEK293 cells,which laid a foundation for the further study on L539fs/47.

EXPRESSION OF HUMAN BETA-DEFENSIN 3 IN COS-7 CELL

To establish a cell line for stable expression of human beta-defensin 3 (hBD3). Methods Full length cDNA of hBD3 was isolated from previously constructed pGEM-hBD3 and then inserted into pcDNA3. The recombinant vector identified carrying hBD3 with right direction was introduced into COS-7 cells by Lipofe-ctamine. Cell clones survived in G418-rich medium and with stable expression of hBD3 in both mRNA and protein levels were identified by RT-PCR and Western blot respectively. Genomic integration of the hBD3 gene with the COS-7 cells was confirmed by Southern dot blot and primary analysis. The antimicrobial activity of the secreted hBD3 was also evaluated. Results COS-7 cells transfected with pcDNA3-hBD3 expressed hBD3 stably in mRNA and protein level. Southern dot blot analysis showed successful integration of the hBD3 gene into the genome of COS-7 cell and the hBD-3 protein secreted into the culture medium showed antimicrobial activity. Conclusion We successfully established a hBD3-expressing cell line.