鼠疫菌特异基因的克隆表达和抗原性分析

目的 在大肠埃希菌中克隆表达鼠疫菌特异基因(YPO1089.pst、ymt),分析重组蛋白的抗原性.方法 利用PCR技术扩增目的 基因,PCR产物经纯化、双酶切后,与质粒载体pET-30a(+)相连接并转化大肠埃希菌BL21(DE3)感受态细胞.经异丙基硫代-β-D-半乳糖苷(IPTG)诱导表达目标蛋白,并进行10%的变性聚丙烯酰胺凝胶电泳,蛋白免疫印迹分析其特异性,最后采用亲和层析法纯化诱导表达的融合蛋白.结果 成功构建了pET-YPO1089、pET-pst和pET-ymt 3个重组表达质粒,经优化诱导表达条件,重组的rYP01089、rPst和rYmt在大肠埃希菌中均得到了稳定高效地表达;免疫印迹结果表明重组的rPst可与鼠疫阳性血清发生特异性的免疫反应;目标蛋白经纯化后纯度可达95%以上.结论 鼠疫菌的特异性抗原能够在原核蛋白表达系统中获得高效表达,rPst具有敏感且特异的免疫学特性,实验结果为开发新型鼠疫诊断试剂奠定了基础.

Cloning and expression of the specific genes from Yersinia pestis and analysis of their antigenicity

Objective To clone and express specific genes (YP01089,psi.ymt) from Yersinia pestis in Escherichia Coli(E.coli)and to analyze the antigenicity of these recombinant proteins.Methods The target genes were amplified by polymerose chmn reaction(PCR).The amplified products were ligated with pET-30a(+) vector after purification and cut by two different restriction enzymes,then these recombinant plasmids were transfefred into the host cells of E.coli BL21(DE3) strain.The target genes were successfully expressed following induction with Isopropyithio-β-D-galactoside(IPTG),and the target proteins were purified by the method of affinity chromatography.Sodium dodecyl sulfate-polyaerylamide gel eleetrophoresis(SDS-PAGE)and Westem blot were used to detect the expressed recombinant protein.Results Three recombinant plasmids were finally constructed. rYP01089,rPst and rYmt were expressed stably and effectively in E.coli thmngh optimizing the induction condition. The Western blot analysis indicated that rPst was capable of binding with positive sernm of phgue.The purity of rest was up to 95%in this stuay.Conclusions This work indicates that the genes of Yersinia pestis are able to be efficiently expressed in the prokaryotie protein expression system.The immune characteristic of rPst is sensitive and specific,80 this study has settled a foundation for developing a new type diagnostic reagent of plague.