Adriamycin-mediated introduction of a limited number of single-strand breaks into supercoiled DNA.
It was reported previously that Adriamycin converts form I covalently closed circular, supercoiled bacteriophage PM2 DNA to the relaxed circular form II DNA; no form III linear DNA was produced as a result of the extracellular action of Adriamycin in the presence of NADH-dehydrogenase. When form II DNA, produced by the action of Adriamycin, was treated with the BAL 31 nuclease, a single sharp DNA band after agarose gel electrophoresis indicated the presence of only full-length linear form III DNA. As one of its activities, the BAL 31 nuclease introduces a single-strand break in the complementary strand opposite a preexisting single-strand break. When form II DNA, produced by the action of gamma irradiation, was reacted with the BAL enzyme, the resulting linear DNA molecules exhibited a broad range of molecular weights, indicating the presence of many single-strand breaks in the substrate form II DNA. When the Adriamycin-produced form II DNA was treated with restriction endonucleases that cleave PM2 DNA at a single site, either with or without pretreatment with the BAL enzyme, the formation of only full-length linear DNA was observed. Thus, the drug is capable of introducing one or only a very limited number of single-strand breaks into supercoiled DNA; furthermore, these breaks are introduced at random sites along the DNA molecules.
Haidle
C W
CW
McKinney
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SH
D004249:DNA Damage; D004277:DNA, Single-Stranded / Q000187:drug effects*; D004278:DNA, Superhelical / Q000187:drug effects*; D004279:DNA, Viral / Q000187:drug effects*; D004317:Doxorubicin / Q000494:pharmacology*; D004706:Endodeoxyribonucleases / Q000494:pharmacology*
D004277:DNA, Single-Stranded; D004278:DNA, Superhelical; D004279:DNA, Viral; D004317:Doxorubicin; D004706:Endodeoxyribonucleases; C038407:exonuclease Bal 31