Expression of the human interferon-alpha 1 gene under transcriptional and translational control of the speA gene.

The human gene for mature interferon-alpha 1 (IFN-alpha 1) was inserted in a new transcription-translation fusion vector system based on the expression and secretion signals of the gene for type A streptococcal pyrogenic exotoxin, speA. As deduced from the known nucleotide sequences of the component elements, the encoded IFN-alpha 1 was a fusion protein carrying an N-terminal extension of 17 amino acids. When inserted in appropriate vectors capable of replication in Escherichia coli, Bacillus subtilis and Streptococcus sanguis, this expression configuration directed the synthesis of antiviral activity in all 3 organisms, as judged by the cythopathic effect inhibition assay of Vesicular Stomatitis Virus. In E. coli JM101, IFN activity was found mainly in the cytoplasmic protein fraction whereas in the gram-positive hosts, it was completely secreted into the culture medium.