Effect of poliovirus double-stranded RNA on viral and host-cell protein synthesis

Cell-free protein-synthesizing systems that initiate on endogenous messenger RNA have been developed from uninfected and poliovirus-infected HeLa cells. Poliovirus double-stranded RNA is an effective inhibitor of protein synthesis in these extracts, and both cell-directed and virus-specific protein synthesis are equally sensitive to the inhibitory action of double-stranded RNA. The concentrations of double-stranded RNA required for inhibition are not achieved in the infected cell at early times after infection when host-cell shut-off occurs, but rather are achieved only late in infection when virus-specific protein synthesis begins to decline. This indicates that double-stranded RNA does not act as a direct agent to inhibit host cell protein synthesis following infection by poliovirus. The possible significance of inhibition by double-stranded RNA of poliovirus-specific protein synthesis is discussed.