Inducible high level synthesis of mature human fibroblast interferon inEscherichia coli

Abstract
We have obtained high level synthesis in Escherichia coli of mature human fibroblast interferon using a plasmid vector that was designed to allow easy coupling of a DNA coding region to the initiator AUG of the replicase gene of the RNA phage MS2 cloned downstream of phage λ 's leftward promoter. The activity of the promoter can be regulated by temperature. Induced cells accumulated the interferon up to 4% of the total cellular protein. The biological activity of the product amounted to 4 × 109 international units per litre of culture. The synthesis of human fibroblast interferon was shown to drastically inhibit the growth rate of the bacterial host.