title: Roles of Aag, Alkbh2, and Alkbh3 in the Repair of Carboxymethylated and Ethylated Thymidine Lesions.
abstract: Environmental and endogenous genotoxic agents can result in a variety of alkylated and carboxymethylated DNA lesions, including N3-ethylthymidine (N3-EtdT), O(2)-EtdT, and O(4)-EtdT as well as N3-carboxymethylthymidine (N3-CMdT) and O(4)-CMdT. By using nonreplicative double-stranded vectors harboring a site-specifically incorporated DNA lesion, we assessed the potential roles of alkyladenine DNA glycosylase (Aag); alkylation repair protein B homologue 2 (Alkbh2); or Alkbh3 in modulating the effects of N3-EtdT, O(2)-EtdT, O(4)-EtdT, N3-CMdT, or O(4)-CMdT on DNA transcription in mammalian cells. We found that the depletion of Aag did not significantly change the transcriptional inhibitory or mutagenic properties of all five examined lesions, suggesting a negligible role of Aag in the repair of these DNA adducts in mammalian cells. In addition, our results revealed that N3-EtdT, but not other lesions, could be repaired by Alkbh2 and Alkbh3 in mammalian cells. Furthermore, we demonstrated the direct reversal of N3-EtdT by purified human Alkbh2 protein in vitro. These findings provided important new insights into the repair of the carboxymethylated and alkylated thymidine lesions in mammalian cells.
authors.affiliation: Department of Chemistry, University of California , Riverside, California, United States.
authors.forename: Changjun
authors.initials: C
authors.lastname: You
authors.affiliation: Environmental Toxicology Graduate Program, University of California , Riverside, California, United States.
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Wang
authors.affiliation: Department of Cancer Biology, Beckman Research Institute , Duarte, California, United States.
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Nay
authors.affiliation: Department of Chemistry, University of California , Riverside, California, United States.
authors.forename: Jianshuang
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Chemistry, University of California , Riverside, California, United States.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Dai
authors.affiliation: Department of Cancer Biology, Beckman Research Institute , Duarte, California, United States.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: O'Connor
authors.affiliation: Department of Chemistry, University of California , Riverside, California, United States.|Environmental Toxicology Graduate Program, University of California , Riverside, California, United States.
authors.forename: Yinsheng
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000071499:AlkB Homolog 2, Alpha-Ketoglutarate-Dependent Dioxygenase / Q000378:metabolism*; D000071500:AlkB Homolog 3, Alpha-Ketoglutarate-Dependent Dioxygenase / Q000378:metabolism*; D000478:Alkylation; D000818:Animals; D002460:Cell Line; D018736:DNA Adducts / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D045647:DNA Glycosylases / Q000378:metabolism*; D004260:DNA Repair; D006801:Humans; D051379:Mice; D013936:Thymidine / Q000031:analogs & derivatives / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D018736:DNA Adducts; C000597427:N3-carboxymethylthymidine; C066706:N(3)-ethylthymidine; C486439:ALKBH3 protein, human; D000071500:AlkB Homolog 3, Alpha-Ketoglutarate-Dependent Dioxygenase; C511887:Alkbh3 protein, mouse; C486440:ALKBH2 protein, human; D000071499:AlkB Homolog 2, Alpha-Ketoglutarate-Dependent Dioxygenase; C511886:Alkbh2 protein, mouse; C021565:3-methyladenine-DNA glycosylase; D045647:DNA Glycosylases; D013936:Thymidine