Biosynthesis of reovirus-specified polypeptides: Expression of reovirus S1-encoded σ1 NS protein in transfected and infected cells as measured with serotype specific polyclonal antibody

Abstract

Polyclonal monospecific antibody was prepared against the reovirus serotype 1 Lang strain nonstructural σ1NS protein encoded by the S1 gene. The antibody was serotype-specific. The σ1NS protein of reovirus serotype 1, but not reovirus serotype 3, was recognized by the polyclonal antibody in both immunoprecipitation and Western immunoblot assays. The σ NS protein expressed in vector-transfected COS cells was indistinguishable by immunoprecipitation and immunoblot analyses from the authentic σ1NS protein synthesized in virus-infected mouse L or monkey COS cells. The temporal appearance of σ1NS protein in virus-infected cells was similar to that of the other reovirus proteins. Both σ1NS and σ1, the two S1 gene products, were observed in the cytoplasm of COS cells by immunofluorescent microscopy, although their staining patterns were distinct from each other. However, σlNS, but not of σ the other reovirion structural proteins, was also detected in the nucleoli of COS cells. These results suggest that σ1NS, like σ1, is a serotype-specific reovirus protein, but unlike of σ1 localized in part to the cell nucleus.