title: Synthesis and mutagenesis of the butadiene-derived N3 2'-deoxyuridine adducts.
abstract: 1,3-Butadiene is a known carcinogen and mutagen that acts through a variety of metabolic intermediates that react with DNA, forming stable and unstable lesions on dG, dA, dC, and dT. The N3 2'-deoxyuridine adducts are a highly stable, stereoisomeric mixture of adducts derived from the reaction of cytosine with the monoepoxide metabolite of butadiene, followed by spontaneous deamination. In this study, the phosphoramidites and subsequent oligodeoxynucleotides containing the N3 2'-deoxyuridine adducts have been constructed and characterized. Using a single-stranded shuttle vector DNA, the mutagenic potential of these adducts has been tested following replication in mammalian cells. Replication past the N3 2'-deoxyuridine adducts was found to be highly mutagenic with an overall mutation yield of approximately 97%. The major mutations that were observed were C to T transitions and C to A transversions. In vitro, these adducts posed a complete block to both the Klenow fragment of Escherichia coli polymerase I and polymerase epsilon, while these lesions significantly blocked polymerase delta. These data suggested a possible involvement of bypass polymerases in the in vivo replication of these lesions. Overall, these findings indicate that the N3 2'-deoxyuridine adducts are highly mutagenic lesions that may contribute to butadiene-mediated carcinogenesis.
authors.affiliation: Center for Research on Occupational and Environmental Toxicology, and Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, 97239-3098, USA.
authors.forename: Priscilla H
authors.initials: PH
authors.lastname: Fernandes
authors.forename: Linda C
authors.initials: LC
authors.lastname: Hackfeld
authors.forename: Ivan D
authors.initials: ID
authors.lastname: Kozekov
authors.forename: Richard P
authors.initials: RP
authors.lastname: Hodge
authors.forename: R Stephen
authors.initials: RS
authors.lastname: Lloyd
mesh_terms: D001483:Base Sequence; D002070:Butadienes / Q000138:chemical synthesis / Q000737:chemistry*; D002273:Carcinogens / Q000138:chemical synthesis / Q000737:chemistry*; D018736:DNA Adducts / Q000138:chemical synthesis / Q000737:chemistry*; D004261:DNA Replication; D003857:Deoxyuridine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009153:Mutagens / Q000737:chemistry; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000737:chemistry
chemical_list: D002070:Butadienes; D002273:Carcinogens; D018736:DNA Adducts; D009153:Mutagens; D009841:Oligonucleotides; D009943:Organophosphorus Compounds; C434331:phosphoramidite; C031763:1,3-butadiene; D003857:Deoxyuridine