Action of bleomycin on programmed synthesis. Influence on enzymatic DNA, RNA and protein synthesis

Abstract

Enzymatic DNA and RNA synthesis from Escherichia coli is strongly influenced by bleomycin. The effects exerted by the antibiotic are nearly identical in the assays using either DNA-dependent DNA polymerase or DNA-dependent RNA polymerase isolated from E. coli. In the experiments with different kinds of DNA templates, DNA always was the primary target of bleomycin action in the enzyme system. DNA and RNA synthesis directed by a DNA rich in dAdo and dThd are inhibited by bleomycin, while the antibiotic stimulates nucleic acid synthesis directed by dGuo, dCyd-rich DNA. The inhibition in DNA-dependent DNA polymerase assays is of the non-competitive type; however, the bleomycin-induced stimulation is competitive to the DNA. Evidence is given showing the initiation step to be the primary target for bleomycin stimulation as well as for inhibition. Protein biosynthesis with a sea urchin system is not affected even at high bleomycin concentrations.