重组人干细胞因子-血小板生成素融合蛋白的表达及活性初步研究

A preliminary study on the expression and biological function of recombinant human SCF-TPO fusion protein

目的研究重组人干细胞因子血小板生成素(SCFTPO)融合蛋白表达的最佳条件及其生物学活性。方法设计引物,利用RTPCR从胎肝细胞中扩增到SCF和TPO氨基端功能区片段,采用基因融合新策略将其融合成SCFTPO融合基因,克隆到pGEMT载体中,构建pET32a/SCFTPO融合基因原核表达载体,在宿主菌E.coliBL21(DE3)plysS中经异丙基βD硫代半乳糖(IPTG)诱导其高表达SCFTPO,SDS聚丙烯酰胺凝胶电泳和Westernblot检测。目的蛋白经包涵体变性,金属螯合层析纯化,透析复性,用细胞因子依赖细胞系MO7e进行细胞增殖实验。结果获得SCFTPO融合基因的高表达,表达量占菌体总蛋白的30%以上。Westernblot法鉴定表达正确,MTT法证明该融合蛋白具有细胞增殖活性,浓度为100ng/ml时刺激活性更强。结论表达并复性后的重组人SCFTPO融合蛋白具有刺激MO7e细胞生长活性。

Objective To study the expression of recombinant human SCF-TPO fusion protein and its biological function. Methods Four primers were designed according to known sequences of TPO and SCF. The functional amino acid domains of TPO and SCF were amplified by RT-PCR from fetus hepatocytes, respectively. The expression plasmid pET32a/SCF-TPO was constructed by VOE gene fusion technique and expressed in E.coli BL21(DE3) plysS as inclusion body after isopropyl-β-D-1-thiogalactopyranoside (IPTG) induction. The fusion protein was tested by SDS-PAGE and Western blot. The biological functions of SCF-TPO fusion protein in MO7e cells was investigated by MTT method after purification with metal chelating chromatography. Results The high expression SCF-TPO fusion protein was obtained, reaching up to 30% of the total cellular protein. Western blot verified the correct fusion expression and MTT results showed the growth promoting effect of the SCF-TPO fusion protein on MO7e cells, with a higher promoting activity at 100 ng/ml. Conclusions Expressed SCF-TPO fusion protein after renaturation has biological activity in promoting the proliferation of MO7e cells.