小鼠OB基因的克隆及在大肠杆菌中的高效表达

Molecular Cloning of Mouse OB Gene and Its High Expression in E.coli

利用RT-PCR技术从小鼠脂肪组织中扩增了OB基因,并利用定向克隆技术克隆至原核表达载体pTO-T7.将构建好的质粒导入表达型大肠杆菌BL21(DE3),IPTG诱导表达,并对表达产物进行Western-blot检测.表达产物利用亲和层析技术进行纯化.结果显示:表达的带有his标签的小鼠leptin融合蛋白,分子量约为20 ku.0.5 mmol/L的IPTG在37℃诱导2.5 h时,leptin融合蛋白的表达量达到最大,达菌体总蛋白50%以上.表达产物经过纯化,纯度可达90%以上.Western-blot杂交显示,小鼠leptin融合蛋白有很强的抗原特异性.

In this study, mouse OB eDNA has been amplified by RT-PCR technique. The eDNA of mouse OB gene was subcloned into pTO-T7 plasmid and the recombinant plasmid has been transformed into Escherichia coli BL21（de3） and induced by IPTG, the induced product was identified by western blotting and purified by affinity chromatography technique. The results showed that the mouse leptin fusion protein with a his-tag was about 20 ku. When the IPTG concentration was 0. 5 mmol/L,the expression products accounted for more than 50% of the total E. coli protein after 2.5 hours inducing in 37℃. After purification,the purity of the mouse leptin fusion protein could accounted for more than 90%. Western blot analysis indicated that the fusion protein could react specifically with anti-leptin body.