日本血吸虫重组质粒pGEX-Sj32的构建及其在大肠埃希菌BL21中的表达

摘要

Objective To construct the recombinant plasmid pGEX-Sj32 of Schistosoma japonicum(Sj )and to research its ex-pression in Escherichia coli (E.coli)BL21.Methods Sj32 gene was amplified by PCR from template of plasmid pET28α-Sj32 ex-tracted from recombinant bacterium BL21 (pET28α-Sj32 )stored by our laboratory,and then cloned into the vector pGEX-1λT to construct pGEX-Sj32.The recombinant plasmid pGEX-Sj32 was transformed into E.coli BL21(DE3).The recombinant strains were induced by isopropyl-β-d-thiogalactoside(IPTG),and the expressed products were identified by SDS-PAGE and Western blot.Re-sults Sj32 coding gene was successfully amplified by PCR and cloned into the vector pGEX-1λT,and the recombinant plasmid pGEX-Sj32 was constructed successfully.The molecular mass of the expressed recombinant protein was proximately 58 000 as de-tected by SDS-PAGE.The amount of the expressed protein was about 21% of the total bacterial protein.Western blot confirmed that the expressed protein could be recognized by the immune sera from rabbit infected with Schistosoma japonicum.Conclusion The recombinant plasmid pGEX-Sj32 is successfully constructed.The Sj32 protein was highly expressed in E.coli and the expressed recombinant protein possesses the specific antigenicity.%目的：构建日本血吸虫（Sj）重组质粒 pGEX-Sj32并研究其在大肠埃希菌 BL21中的表达效率。方法从该实验室保存的 BL21（pET28α-Sj32）重组菌中抽提质粒 pET28α-Sj32，PCR 扩增 Sj32抗原编码基因，定向克隆入穿梭载体 pGEX-1λT，构建重组质粒 pGEX-Sj32。将重组质粒转化大肠埃希菌 BL21（DE3），经异丙基硫代-β-D-半乳糖苷（IPTG）诱导表达；表达产物用SDS-PAGE 和 Western blot 进行鉴定。结果 PCR 成功扩增出 Sj32编码基因，并成功构建了重组质粒 pGEX-Sj32；SDS-PAGE显示相对分子质量约为58×103的重组蛋白，薄层扫描分析显示表达蛋白约占菌体总蛋白的21％；Western blot 显示重组蛋白可被日本血吸虫感染兔血清识别。结论成功构建日本血吸虫重组质粒 pGEX-Sj32，该重组质粒在大肠埃希菌 BL21中得到了高效表达，且表达蛋白具有特异的抗原性。