title: The region of XRCC1 which harbours the three most common nonsynonymous polymorphic variants, is essential for the scaffolding function of XRCC1.
abstract: XRCC1 functions as a non-enzymatic, scaffold protein in single strand break repair (SSBR) and base excision repair (BER). Here, we examine different regions of XRCC1 for their contribution to the scaffolding functions of the protein. We found that the central BRCT1 domain is essential for recruitment of XRCC1 to sites of DNA damage and DNA replication. Also, we found that ectopic expression of the region from residue 166-436 partially rescued the methyl methanesulfonate (MMS) hypersensitivity of XRCC1-deficient EM9 cells, suggesting a key role for this region in mediating DNA repair. The three most common amino acid variants of XRCC1, Arg194Trp, Arg280His and Arg399Gln, are located within the region comprising the NLS and BRCT1 domains, and these variants may be associated with increased incidence of specific types of cancer. While we could not detect differences in the intra-nuclear localization or the ability to support recruitment of POLβ or PNKP to micro-irradiated sites for these variants relative to the conservative protein, we did observe lower foci intensity after micro-irradiation and a reduced stability of the foci with the Arg280His and Arg399Gln variants, respectively. Furthermore, when challenged with MMS or hydrogen peroxide, we detected small but consistent differences in the repair profiles of cells expressing these two variants in comparison to the conservative protein.
authors.affiliation: Department of Cancer Research and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Audun
authors.initials: A
authors.lastname: Hanssen-Bauer
authors.forename: Karin
authors.initials: K
authors.lastname: Solvang-Garten
authors.forename: Karin Margaretha
authors.initials: KM
authors.lastname: Gilljam
authors.forename: Kathrin
authors.initials: K
authors.lastname: Torseth
authors.forename: David M
authors.initials: DM
authors.lastname: Wilson
authors.forename: Mansour
authors.initials: M
authors.lastname: Akbari
authors.forename: Marit
authors.initials: M
authors.lastname: Otterlei
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004249:DNA Damage; D019951:DNA Polymerase beta / Q000378:metabolism; D004260:DNA Repair / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D045643:DNA Repair Enzymes / Q000378:metabolism; D004261:DNA Replication / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D019913:Nuclear Localization Signals; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000187:drug effects / Q000528:radiation effects; D000076105:X-ray Repair Cross Complementing Protein 1
chemical_list: D004268:DNA-Binding Proteins; D019913:Nuclear Localization Signals; D018809:Proliferating Cell Nuclear Antigen; D000076105:X-ray Repair Cross Complementing Protein 1; C000619371:XRCC1 protein, human; D008741:Methyl Methanesulfonate; C530380:PNKP protein, human; D017853:Phosphotransferases (Alcohol Group Acceptor); D019951:DNA Polymerase beta; D045643:DNA Repair Enzymes