Characterization of Intracellular Ribonucleic Acid Specific for the Murine Sarcoma-Leukemia Virus Complex

Abstract

Virus particles were continuously produced by a cell line (78A1) of rat embryo fibroblasts that had been transformed by the murine sarcoma-leukemia virus complex. Since most of the mature virions were found in the extracellular fluid and were not cell-associated, a measurable quantity of viral ribonucleic acid (RNA) could not be extracted from these cells. Cycloheximide, a protein inhibitor, was successfully used to accumulate viral RNA within the cells. This ribonuclease-sensitive RNA, with a sedimentation coefficient of 71 S , had the same base composition as the high molecular weight RNA ( S 20,w = 71) isolated from purified virions released by the transformed cells.