Association of Viral Ribonucleic Acid with Cellular Membranes in Chick Embryo Cells Infected with Sindbis Virus

Membranes from cells infected with Sindbis virus had associated with them viral ribonucleic acid (RNA) polymerase and about 60 to 70% of the viral RNA labeled when short pulses were used. This RNA contained most of the replicative intermediate and replicative form of viral RNA found in the infected cells. The use of "Mg(2+) sarkosyl crystals" permitted the isolation of membrane-bound nucleic acids and allowed the demonstration that Sindbis virus RNA was synthesized on a membrane-viral RNA complex. Viral RNA from the infecting virions first became associated with the membranes during the latent period and, subsequently, slowly detached. The attachment of the viral RNA to the membranes did not require active viral RNA polymerase, since RNA from ts6, an RNA(-) temperature-sensitive mutant of Sindbis virus, associated with cellular membranes at a nonpermissive temperature. However, the subsequent detachment of the RNA from the membranes was restricted in the absence of viral RNA synthesis. The results indicate that association of viral RNA with cellular membranes may represent an early step occurring during the replication of Sindbis virus RNA.