Identification of nonstructural proteins encoded by viruses of the Bunyamwera serogroup (family Bunyaviridae).

The proteins synthesized in BHK cells infected with nine members of the Bunyamwera serogroup (family Bunyaviridae, Bunyavirus genus) were analyzed by polyacrylamide gel electrophoresis. In addition to the virus structural proteins, a number of virus-coded nonstructural proteins were detected. One protein, designated NS1, was shown to be related to the nucleocapsid protein by one-dimensional peptide mapping. A second protein, NS2, was mapped to the M RNA segment by gel electrophoretic analysis of the proteins synthesized in cells infected with reassortants of Batai, Bunyamwera, and Maguari viruses of known genotype. A third protein, NS3, was mapped to the S RNA segment by its pattern of labeling with [35S]cysteine in cells infected with reassortant viruses: the NS3 protein was only labeled when the S RNA segment of Bunyamwera virus was present. The mapping of NS3 was confirmed by in vitro translation of mRNAs which hybridized to recombinant plasmids containing S gene-specific sequences.