Preferential DNA damage in thep53 gene by benzo[a]pyrene metabolites in cytochrome P4501A1-expressing xeroderma pigmentosum group A cells

摘要: Gene-specific DNA damage levels were determined by quantitative polymerase chain reaction (QPCR) after treating cytochrome P450 (CYP) 1A1-expressing xeroderma pigmentosum fibroblasts with [3H]benzo[a]pyrene-trans-7,8-dihydrodiol ([3H]BPD) or [3H]benzo[a]pyrene-trans-7,8-dihydrodiol-9, 10-epoxide([3H]BPDE). in the p53 gene (which is transcriptionally active) and β-globin inactive) was measured cells treated [3H](±)-anti-BPDE, [3H](±)-BPD, [3H](−)-BPD. adduct formation genome overall measuring incorporation of 3H into DNA. a fragment (exons 8–9, 445 bp) readily detected QPCR. either not much reduced similarly sized target 1–2, 551 bp). At equivalent genomic adducts, BPD treatment induced more than BPDE did. The lesion frequencies genes purified vitro same, indicating that there no sequence-specific basis for preferential cells. both showed dose response to frequency BPD-induced lesions sixfold sevenfold greater 200- 300-fold bulk 30- 50-fold data indicate distribution BPDE-induced dramatically nonrandom suggest nonrandomness governed sequence composition, chromatin structure, rate. © 1996 Wiley-Liss, Inc.