Cloning and expression in biologically active form of the gene for human interferon alpha 2 in Streptomyces lividans

A fragment of human DNA encoding the mature form of interferon alpha 2 (hIFN-alpha 2), and carrying both an in-phase ATG initiation codon and the ribosome binding site (RBS) of the Escherichia coli membrane lipoprotein gene (lpp), was fused to the aminoglycoside phosphotransferase gene (aph) promoter (aphP) from Streptomyces fradiae. When this construction was inserted, in the two possible orientations, in the Streptomyces plasmid pIJ702, plasmids pNIS19 and pNIS91 were obtained. A 20-kDa polypeptide that immunoreacted with an hIFN-alpha 2 monoclonal antibody was expressed in S. lividans clones carrying these plasmids. Moreover, these clones contained an intracellular antiviral activity similar to that of hIFN-alpha 2. When plasmids pNIS19 and pNIS91 were deprived of the aphP no expression of activity was found. Therefore, it is concluded that the hIFN gene can be efficiently expressed in Streptomyces as directed by the aph gene promoter.