Inhibition of recovery from bleomycin-induced potentially lethal damage

Mammalian cells are able to recover from bleomycin (Bleo)-induced potentially lethal damage. We examined the influences of inhibitors of DNA, RNA, or protein synthesis on that recovery. Cytosine arabinoside and cycloheximide did not inhibit recovery from Bleo-induced damage; however, actinomycin D (Act D) did inhibit it. At a dose that produced minimal cell killing and inhibited only RNA synthesis, inhibition of recovery by Act D was immediate and complete.