猪链球菌2型毒力因子部分片段的克隆与表达

根据猪链球菌2型(Streptococcussuistype2)胞外蛋白因子(extracellularfactorprotein,EF)的基因(epf)序列,设计合成一对引物,以猪链球菌2型江苏分离株SS2-H的基因组为模板,扩增epf基因1585-2547位序列,进行T/A克隆,转化入宿主菌DH5α中。提取阳性克隆质粒进行双酶切并纯化,将目的片段向克隆到表达载体pET-32a中组氨酸的下游,将重组质粒转化入大肠杆菌BL21中,经IPTG诱导可表达分子量约为53000的融合蛋白。免疫转印分析表明,该融合蛋白具有EF的抗原表位。

Cloning and expression of the partial fragment of gene encoding for the virulence factor of Streptococcus suis type 2

The gene fragment of 1585 to 2572 bp in length encoding the extracellular factor proteins was amplified from genomic DNA of Streptococcus suis type 2 strain SS 2 H isolated in Jiangsu province by PCR. The PCR products was later cloned into T vector and transformed into host strain DH5a, and the plasmid of positive clones was extracted ,digested with enzymes and purified. Then the fragment was cloned to expression vector pET 32a just on the down stream of the histidine residue.And the recombinant plasmid was transformed to E.coli BL21. The fusion protein with a molecular weight of about 53 000 could be expressed after induction with IPTG. And it possesses of antigenic epitopes of extracellular factor protein.