Reovirus-coded polypeptides in infected cells: Isolation of two native monomeric polypeptides with affinity for single-stranded and double-stranded RNA, respectively

Abstract The cytoplasm of cells infected with rovirus contains 8 of the 10 polypeptides coded by this virus in free form in amounts equivalent to 1 to 10% of the progeny virus yield. All of these polypeptides exist in monomeric form except polypeptides μ1 and μ2 which occur as dimers, the form in which they are present in virions. One of these polypeptides, σ3, a constituent of the outer capsid shell, binds strongly to double-stranded RNA; it can be isolated in high yield in pure form by passing extracts of infected cells through columns of poly(IC)-cellulose and eluting. Another polypeptide, σ2A, a nonstructural polypeptide, binds strongly to single-stranded RNA and appears to exist in infected cells complexed with RNA. It can be isolated in high yield in pure form by passing extracts of infected cells, suitably treated to dissociate these complexes, through columns of poly(A)-cellulose and eluting. The possible significance of the highly specific nucleic acid affinities of these two reovirus-coded polypeptides is discussed.