EXPRESSION OF A TRUNCATED HUMAN MACROPHAGE-COLONY-STIMULATING FACTOR IN ESCHERICHIA-COLI

A truncated cDNA of the human macorophage 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 T-7 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.