Effect of in vitro cleavage of apurinic/apyrimidinic sites on bleomycin-induced mutagenesis of repackaged lambda phage.
Previous studies have revealed bleomycin to be a potent base-substitution mutagen in repackaged phage lambda. In order to assess the role of apurinic/apyrimidinic (AP) sites in bleomycin-induced mutagenesis, bleomycin-damaged lambda DNA was treated with putrescine or endonuclease IV to effect cleavage of bleomycin-induced AP sites. The DNA was then packaged, the phage grown in SOS-induced E. coli, and the frequency of clear-plaque mutants in the progeny was determined. Bleomycin-induced mutagenesis was decreased approx. 2-fold by treating the DNA with putrescine, but was unaffected by endonuclease IV. The results are consistent with the production of bleomycin-induced mutation at certain AP sites having a closely opposed single-strand break, since such sites are cleaved by putrescine but not by endonuclease IV.
Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298.
R J
RJ
Steighner
L F
LF
Povirk
D010582:Bacteriophage lambda / Q000187:drug effects / Q000235:genetics; D001482:Base Composition; D001761:Bleomycin / Q000378:metabolism / Q000633:toxicity*; D004279:DNA, Viral / Q000187:drug effects* / Q000378:metabolism; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D043223:Deoxyribonuclease IV (Phage T4-Induced); D004587:Electrophoresis, Agar Gel; D004706:Endodeoxyribonucleases / Q000494:pharmacology; D009152:Mutagenicity Tests; D009153:Mutagens / Q000494:pharmacology*; D010957:Plasmids / Q000235:genetics; D011700:Putrescine / Q000494:pharmacology
D004279:DNA, Viral; D009153:Mutagens; D001761:Bleomycin; D004706:Endodeoxyribonucleases; D043223:Deoxyribonuclease IV (Phage T4-Induced); D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D011700:Putrescine