A requirement of RNA synthesis for oxidation-dependent biosynthesis in sarcoma 37 ascites-tumor cells

Abstract

1. 1. In Sarcoma 37 cells synthesis of total cellular RNA was promptly suppressed by actinomycins D, C 2, and C 3, mithramycin, rubidomycin, nogalamycin and 5,6-dichloro-1-β- d-ribofuranosylbenzimidazole. 2. 2. Each of the compounds inhibited synthesis of RNA in the presence of glucose, but inhibition of synthesis of total protein by these cells occurred only in the absence of glucose. Sterol synthesis was similarly inhibited, with relief of the inhibition occurring after addition of glucose. 3. 3. Aminoacyl-RNA synthetase activity of soluble preparations from actinomycin-treated cells did not differ from controls, and amino acid acceptor activity of transfer RNA was also unaffected, despite previous indications that amino acid incorporation into transfer RNA was inhibited in intact cells which had been incubated with actinomycin D. 4. 4. A compartmentation mechanism involving adenine nucleotides is proposed to explain the inhibitory effects of actinomycins and the other inhibitors of RNA synthesis on synthesis of protein and sterols. 5. 5. These inhibitory effects indicate a requirement of RNA synthesis in these cells for certain biosynthetic processes under oxidative conditions; the results are not interpreted to indicate an effect of actinomycin other than inhibition of synthesis of RNA.