VACCINIA VIRUS DIRECTED RNA: ITS FATE IN THE PRESENCE OF ACTINOMYCIN.

RNA similar in base composition to viral DNA is formed in the cytoplasm of HeLa cells infected with vaccinia virus. This RNA is found both in polyribosomes and in a broad 30S to 74S region in a sucrose density gradient. When infected cells are exposed to actinomycin, the amount of this DNA-like RNA in the 30S to 74S region is unchanged. Under the same conditions, 70 percent of the polyribosome-associated DNA-like RNA is degraded to acidsoluble fragments within 2 hours, and protein synthesis is reduced by 90 percent.