EXPRESSION OF OVINE GAMMA-INTERFERON IN ESCHERICHIA-COLI AND CORYNEBACTERIUM-GLUTAMICUM

Bacteria of two species, Escherichia coli and Corynebacterium glutamic um, were used as hosts to express recombinant ovine gamma interferon a s a fusion protein with glutathione S-transferase. The recombinant gam ma interferon produced by both bacteria was biologically active in vit ro and was recognized by anti-gamma interferon monoclonal antibodies. E. coli produced large amounts of soluble recombinant protein which co uld be purified by a simple affinity chromatography method. Only a sma ll fraction of the recombinant protein made by C. glutamicum was recov ered by this method. Expression of recombinant protein in C. glutamicu m was unstable but could be controlled by increased regulation of the tac promoter. Both hosts expressed ovine gamma interferon at high leve ls, with the recombinant protein making up a significant proportion of the cellular protein content.