title: In vivo benzo[a]pyrene diol epoxide-induced alkali-labile sites are not apurinic sites.
abstract: We have used endonuclease IV from Escherichia coli as a probe for apurinic sites in the DNA of HeLa cells following treatment with an activated diol epoxide derivative of benzo[a]pyrene. DNA strand breaks and alkali-labile sites were observed that were repaired following exposure to the carcinogenic alkylating agent. The alkali-labile sites were not substrates for the apurinic site-specific endonuclease IV. We conclude that the alkali-labile sites formed in vivo by benzo[a]pyrene derivatives are not apurinic sites and probably arise as a consequence of rearrangement of the abundant N2-guanine adducts. This finding questions the involvement of apurinic sites in the mutagenic activity of benzo[a]pyrene.
authors.affiliation: Department of Microbiology and Immunology, University of Western Ontario, London, Canada.
authors.forename: M F
authors.initials: MF
authors.lastname: Moran
authors.forename: K
authors.initials: K
authors.lastname: Ebisuzaki
mesh_terms: D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide / Q000494:pharmacology*; D000468:Alkalies; D004249:DNA Damage; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D043223:Deoxyribonuclease IV (Phage T4-Induced); D004706:Endodeoxyribonucleases; D029968:Escherichia coli Proteins; D006367:HeLa Cells; D006801:Humans
chemical_list: D000468:Alkalies; D029968:Escherichia coli Proteins; D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide; D004706:Endodeoxyribonucleases; D043223:Deoxyribonuclease IV (Phage T4-Induced); C468972:endonuclease IV, E coli; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase