EXPRESSION OF SOLUBLE, ACTIVE HUMAN MACROPHAGE-COLONY-STIMULATING FACTOR IN ESCHERICHIA-COLI

Human macrophage colony stimulating factor (M-CSF) has been successful ly overexpressed in Escherichia coli AD494 (DE3) with an expression le vel of approximate 26 % of the total cellular proteins. The truncated human M-CSF gene encoding tile amino-terminal 149 amino acids was subc loned into the prokaryotic expression vector pET11d under the control of the inducible T7 promoter. Nearly 40 % of the recombinant protein w as in the soluble fraction which showed obvious stimulating effects on mouse macrophage colony formation and had an M-CSF specific activity of similar to 1 x 10(6) units/mg soluble protein.