[Expression and mutagenesis of genes coding for protein synthesis in the influenza virus].

Double-stranded cDNA copies of the neuraminidase genes of influenza viruses A/Tokyo/3/67 (N2), A/tern/Australia/G70C/75 (N9), and B/Lee/40, and the hemagglutinin genes of A/Memphis/1/71 (H3) and B/Hong Kong/8/73 were cloned into a SV40 vector in which the late region was replaced by the influenza sequences. Thus the influenza genes were expressed in transfected cells under the control of the SV40 late promoter. The Tokyo/67 neuraminidase gene was modified by oligonucleotide-directed site-specific in vitro mutagenesis.