Mutagenic bypass of the butadiene-derived 2'-deoxyuridine adducts by polymerases eta and zeta.
Butadiene is a ubiquitous environmental chemical carcinogen that when activated to its monoepoxide intermediate can react with the N3 position of cytosine, resulting in two stereoisomeric adducted bases that rapidly deaminate to N3 2'-deoxyuridine lesions. We have previously shown that replication of DNAs containing these adducts through mammalian cells resulted in approximately 97% mutagenicity, predominantly C to T transitions. Since replicative DNA polymerases were blocked by these lesions in vitro, translesional polymerases were assessed for their ability to bypass these adducts. While polymerases iota, kappa and zeta were significantly blocked one nucleotide prior to the lesion, pol eta incorporated nucleotides opposite the adducts with a preference for insertion of a G or A. Following polymerase dissociation and reassociation, pol eta was also able to extend primers with mispaired termini opposite the lesions, with extensions from the A and T mismatched primer termini being the most efficient. Pol zeta was also able to extend primers containing all mismatched nucleotides opposite the lesions, with the most efficient extension occurring off of the A mismatched primer.
Fernandes
Priscilla H
PH
Center for Research on Occupational and Environmental Toxicology and the Department of Molecular and Medical Genetics, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, United States.
Lloyd
R Stephen
RS
D000818:Animals; D001483:Base Sequence; D002070:Butadienes / Q000378:metabolism*; D019556:COS Cells; D002522:Chlorocebus aethiops; D018736:DNA Adducts / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D003856:Deoxyuracil Nucleotides / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D016296:Mutagenesis; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D000099270:Y-Family DNA Polymerases
D002070:Butadienes; D018736:DNA Adducts; D017931:DNA Primers; D004259:DNA-Directed DNA Polymerase; D003856:Deoxyuracil Nucleotides; D011994:Recombinant Proteins; C425929:DNA polymerase zeta; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases