缩短的人巨噬细胞集落刺激因子（M－CSF）在大肠杆菌中的表达

本文用聚合酶链反应（ＰＣＲ）获得了一个缩短的人巨噬细胞集落刺激因子（编码３～１４９氨基酸）ｃＤＮＡ基因，并克隆在质粒ｐＥＴ３ｄ中，在Ｔ７启动子指导下，在大肠杆菌ＢＬ２１（ＤＥ３）ＬｙｓＥ中获得了和一个６组氨酸短肽标签的融合表达。重组的融合ｍ－ＣＳＦ表达量占菌体总蛋白的１２％，表达产物一部分以不溶性包涵体形式存在，另一部分则以可溶性蛋白存在。经过金属螫合亲和层析一步纯化，所得的融合（Ｈｉｓ）６－Ｍ－ＣＳＦ在还原型ＳＤＳ－ＰＡＧＥ上基本呈一条均一的蛋白质条带。

^Expression of a Truncated Human Macrophage Colony-stimulating Factor in E. coli

A truncated cDNA of the human macrophage colony-stimulating factor gene, encoding amino acid residues from 3 to 149 of the native M-CSF, was isolated by using the polymerase chain reaction and inserted into plasmid pET3d. It directs the expression of truncated M-CSF fused with a six-histidine tail peptide in E. coli BL21(DE3) LysE under the control of T7 promoter. The expression level of the truncated M-CSF is twelve percent of total cellular proteins, with half of the product accumulated as inclusion bodies and the other part as soluble protein. Through the metalaffinity chromatography, the recombinant truncated M-CSF showed an almost homogenous protein band on reducing SDS-PAGE.