title: Two-step error-prone bypass of the (+)- and (-)-trans-anti-BPDE-N2-dG adducts by human DNA polymerases eta and kappa.
abstract: Benzo[a]pyrene is a polycyclic aromatic hydrocarbon (PAH) associated with potent carcinogenic activity. Mutagenesis induced by benzo[a]pyrene DNA adducts is believed to involve error-prone translesion synthesis opposite the lesion. However, the DNA polymerase involved in this process has not been clearly defined in eukaryotes. Here, we provide biochemical evidence suggesting a role for DNA polymerase eta (Poleta) in mutagenesis induced by benzo[a]pyrene DNA adducts in cells. Purified human Poleta predominantly inserted an A opposite a template (+)- and (-)-trans-anti-BPDE-N2-dG, two important DNA adducts of benzo[a]pyrene. Both lesions also dramatically elevated G and T mis-insertion error rates of human Poleta. Error-prone nucleotide insertion by human Poleta was more efficient opposite the (+)-trans-anti-BPDE-N2-dG adduct than opposite the (-)-trans-anti-BPDE-N2-dG. However, translesion synthesis by human Poleta largely stopped opposite the lesion and at one nucleotide downstream of the lesion (+1 extension). The limited extension synthesis of human Poleta from opposite the lesion was strongly affected by the stereochemistry of the trans-anti-BPDE-N2-dG adducts, the nucleotide opposite the lesion, and the sequence context 5' to the lesion. By combining the nucleotide insertion activity of human Poleta and the extension synthesis activity of human Polkappa, effective error-prone lesion bypass was achieved in vitro in response to the (+)- and (-)-trans-anti-BPDE-N2-dG DNA adducts.
authors.affiliation: Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536, USA.
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Wu
authors.forename: Dongyu
authors.initials: D
authors.lastname: Guo
authors.forename: Olga
authors.initials: O
authors.lastname: Rechkoblit
authors.forename: Nicholas E
authors.initials: NE
authors.lastname: Geacintov
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Wang
mesh_terms: D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D004247:DNA / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D018736:DNA Adducts / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013237:Stereoisomerism; D000099270:Y-Family DNA Polymerases
chemical_list: D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide; D004247:DNA; D018736:DNA Adducts; D004259:DNA-Directed DNA Polymerase; D011993:Recombinant Fusion Proteins; C043931:benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide-DNA; C404302:POLK protein, human; D000099270:Y-Family DNA Polymerases; C112338:Rad30 protein