Site-specific mutagenesis of the human fibroblast interferon gene.

Abstract
Human fibroblast interferon has 3 Cys residues, located at amino acid positions 17, 31 and 141. Using the technique of site-specific mutagenesis with a synthetic oligonucleotide primer, the codon for Cys 17 was changed to a codon for Ser. The resulting interferon, IFN-.beta. Ser-17, retains the antiviral, natural killer cell activation and antiproliferative activities of native fibroblast interferon. The purified IFN-.beta. Ser-17 protein has an antiviral specific activity of 2 .times. 108 U/mg, similar to that of purified native fibroblast interferon. The purified protein is stable to long-term storage at -70.degree. C.