title: Bypass of a psoralen DNA interstrand cross-link by DNA polymerases β, ι, and κ in vitro.
abstract: Repair of DNA interstrand cross-links in mammalian cells involves several biochemically distinctive processes, including the release of one of the cross-linked strands and translesion DNA synthesis (TLS). In this report, we investigated the in vitro TLS activity of a psoralen DNA interstrand cross-link by three DNA repair polymerases, DNA polymerases β, κ, and ι. DNA polymerase β is capable of bypassing a psoralen cross-link with a low efficiency. Cell extracts prepared from DNA polymerase β knockout mouse embryonic fibroblasts showed a reduced bypass activity of the psoralen cross-link, and purified DNA polymerase β restored the bypass activity. In addition, DNA polymerase ι misincorporated thymine across the psoralen cross-link and DNA polymerase κ extended these mispaired primer ends, suggesting that DNA polymerase ι may serve as an inserter and DNA polymerase κ may play a role as an extender in the repair of psoralen DNA interstrand cross-links. The results demonstrated here indicate that multiple DNA polymerases could participate in TLS steps in mammalian DNA interstrand cross-link repair.
authors.affiliation: Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States.
authors.forename: Leigh A
authors.initials: LA
authors.lastname: Smith
authors.forename: Alena V
authors.initials: AV
authors.lastname: Makarova
authors.forename: Laura
authors.initials: L
authors.lastname: Samson
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Thiesen
authors.forename: Alok
authors.initials: A
authors.lastname: Dhar
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Bessho
mesh_terms: D000818:Animals; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004247:DNA / Q000187:drug effects; D019951:DNA Polymerase beta / Q000378:metabolism*; D004260:DNA Repair / Q000502:physiology*; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D005363:Ficusin / Q000378:metabolism*; D006801:Humans; D051379:Mice; D000094769:DNA Polymerase iota; D000099270:Y-Family DNA Polymerases
chemical_list: D003432:Cross-Linking Reagents; D004247:DNA; D019951:DNA Polymerase beta; D004259:DNA-Directed DNA Polymerase; D005363:Ficusin; D000094769:DNA Polymerase iota; C404302:POLK protein, human; D000099270:Y-Family DNA Polymerases