Membrane-bound virions of coxsackievirus B4: cellular localization, analysis of the genomic RNA, genome-linked protein, and effect on host macromolecular synthesis

Hela cells infected with several group B coxsackieviruses contain, in addition to standard virions, a population of virus-specific ribonucleoprotein particles which we (5) designated membrane-bound virions (MBV). MBVs differ from standard virions in buoyant density, yield, appearance, protein composition and infectivity. Here we present several new features of MBVs of coxsackievirus B4. The MBVs are lighter (rho about 1.30) and are localized in rough membranes, intermixed with virions. They contain 35S virion RNA covalently linked with a small protein, VPg. The VPg contain two proteins of different charge. MBV VPg is considerably smaller than the 5300-dalton virion VPg. MBV RNA is homologous to the base sequence present in B4 virus double-stranded RNA. The T1 oligonucleotide fingerprint of MBV RNA is distinguishable from that of virion RNA by one oligonucleotide. Several oligonucleotides of virion RNA appear to occur in submolar quantities in MBV RNA. MBVs are 75 to greater than 200 times less infective; they inhibit host cell macromolecular synthesis less efficiently than virions. In coinfected cells, the extent of inhibition of host synthesis is less severe than in cells infected with virions alone, which suggest interference by MBV particles.