Bleomycin inhibition of DNA synthesis in isolated enzyme systems and in intact cell systems.

Abstract Blcomycin (BLM) inhibits DNA and RNA synthesis in different isolated enzyme systems. The inhibition effect can be reduced by adcling RNA to the reaction mixture. The activity of the RNA dependent DNA polymerase and of a cell-free protein synthesizing system is not affected by BLM. The antibiotic reduces cell proliferation (L5178y mouse lymphoma cells) in vitro at low concentrations by cytostatis and at higher concentrations by cytotoxicity. In BLM-treated L5178y cells DNA synthesis is strongly reduced, while RNA and protein synthesis are not affected. In vivo , using growing quail oviducts, cell proliferation and cytodifferentiation are markedly inhibited after BLM treatment. This …