Characterization of bleomycin action on DNA.

Abstract

Cleavage of SV40 DNA by bleomycin was assayed quantitatively in vitro in the presence of various polynucleotides. SV40 DNA was protected from bleomycin-induced cleavage by native or denatured DNA of other origins, poly dG-C.cntdot.poly dG-C, poly dA-T.cntdot.poly dA-T and poly dA-T (denatured) but not by tRNA of Escherichia coli, apurinic acid, poly dA, poly dT and various deoxyribooligonucleotides. Various bleomycins and their derivatives and various fragments of bleomycin were tested for possible activity in cleaving SV40 DNA and from the results some structure-activity relationships for the action of bleomycin to act on DNA were outlined. Actinomycin D stimulated bleomycin action while ethidium bromide inhibited it.