SOLUBILIZED RNA REPLICATION COMPLEX FROM SEMLIKI FOREST VIRUS-INFECTED CELLS

The postmitochondrial pellet from SFV-infected cells was incubated under in vitro RNA-synthesizing conditions in the presence of [3H]UTP to label nascent chains in the RNA replication complex. The solubilized complex was purified by centrifugation in a glycerol gradient followed by a sucrose gradient in which it sedimented with a peak at 34 S. It contained double-stranded RNA which by mild ribonuclease treatment was converted to replicative forms I, II, and III, indicating that it was derived from replicative intermediates synthesizing 42 S and 26 S RNA. A similar structure was also isolated from infected cells labeled with [3H]uridine early in infection. The only virus-specific proteins associated with the complex were ns70, ns72, and ns86. The presence of ns70 and ns72 was confirmed by tryptic peptide mapping. © 1979.