人CTLA-4Ig融合基因减毒鼠伤寒沙门菌真核表达载体的构建及表达

目的构建能稳定表达人CTLA4 Ig融合基因的减毒鼠伤寒沙门菌真核表达载体,探讨其在哺乳动物细胞中的表达并对表达产物进行鉴定。方法用touchdown PCR法扩增CTLA-4 Ig融合基因,将PCR产物连接真核表达载体pcDNA3.1( ),构建pcDNA3.1( )-CTLA-4 Ig,用电穿孔仪转入减毒鼠伤寒沙门菌SL7207。将表达质粒转染COS-7细胞,SDS-PAGE、W estern b lot检测转染细胞裂解上清中目的蛋白的表达。结果酶切鉴定和基因序列测定显示重组质粒构建成功。在pcDNA3.1( )-CTLA-4 Ig质粒转染后48 h细胞裂解上清中,检测到CTLA-4 Ig融合蛋白的表达,该蛋白能与抗人CTLA-4单抗特异结合。结论成功构建了能稳定表达人CTLA4 Ig融合基因的减毒鼠伤寒沙门菌真核表达载体,并在哺乳动物细胞中成功表达有生物学活性的重组人CTLA-4 Ig蛋白。

Construction of eukaryotic expression vector of attenuated Salmonella typhimurium containing hCTLA4Ig gene and expression in COS-7 cells

Objective To construct eukaryotic expression vector of attenuated Salmonella typhimurium containing hCTLA-4Ig cDNA and identify its expression in COS-7 cells for the further study of function in SLE models. Methods Touchdown PCR was used to amplify hCTLA-4Ig cDNA.The PCR product was ligated into the multiple clone site of eukaryotic expression vector pcDNA3.1( ) by gene recombination technique.Then the recombinated plasmid pcDNA3.1( )-CTLA-4Ig was transfected into COS-7 cells using DOTAP.The expression of interest protein in the supernatant of the cell disruption was detected with SDS-PAGE and Western blotting.Results Restriction analysis and DNA sequence analysis showed that the CTLA-4Ig cDNA had been successfully inserted into pcDNA3.1( ) eukaryotic expression vector.The interest protein could be detected in the supernatant of cell disruption 48h after the transfection of pcDNA3.1( )-CTLA-4Ig.This protein specifically bound with human CTLA-4 monoclonal antibody.Conclusion The eukaryotic expression vector containing hCTLA-4Ig gene was successfully constructed and bioactive interest protein could be successfully expressed in mammalian cells.