title: Cockayne syndrome group B protein stimulates repair of formamidopyrimidines by NEIL1 DNA glycosylase.
abstract: Cockayne syndrome (CS) is a premature aging condition characterized by sensitivity to UV radiation. However, this phenotype does not explain the progressive neurodegeneration in CS patients. It could be due to the hypersensitivity of CSB-deficient cells to oxidative stress. So far most studies on the role of CSB in repair of oxidatively induced DNA lesions have focused on 7,8-dihydro-8-oxoguanine. This study examines the role of CSB in the repair of formamidopyrimidines 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyGua) and 4,6-diamino-5-formamidopyrimidine (FapyAde), which are substrates for endonuclease VIII-like (NEIL1) DNA glycosylase. Results presented here show that csb(-/-) mice have a higher level of endogenous FapyAde and FapyGua in DNA from brain and kidney than wild type mice as well as higher levels of endogenous FapyAde in genomic DNA and mtDNA from liver. In addition, CSB stimulates NEIL1 incision activity in vitro, and CSB and NEIL1 co-immunoprecipitate and co-localize in HeLa cells. When CSB and NEIL1 are depleted from HeLa cells by short hairpin RNA knockdown, repair of induced FapyGua is strongly inhibited. These results suggest that CSB plays a role in repair of formamidopyrimidines, possibly by interacting with and stimulating NEIL1, and that accumulation of such modifications may have a causal role in the pathogenesis of CS.
authors.affiliation: Laboratory of Molecular Gerontology, NIA Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, USA.
authors.forename: Meltem
authors.initials: M
authors.lastname: Muftuoglu
authors.forename: Nadja C
authors.initials: NC
authors.lastname: de Souza-Pinto
authors.forename: Arin
authors.initials: A
authors.lastname: Dogan
authors.forename: Maria
authors.initials: M
authors.lastname: Aamann
authors.forename: Tinna
authors.initials: T
authors.lastname: Stevnsner
authors.forename: Ivana
authors.initials: I
authors.lastname: Rybanska
authors.forename: Güldal
authors.initials: G
authors.lastname: Kirkali
authors.forename: Miral
authors.initials: M
authors.lastname: Dizdaroglu
authors.forename: Vilhelm A
authors.initials: VA
authors.lastname: Bohr
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D004247:DNA / Q000235:genetics* / Q000378:metabolism*; D045647:DNA Glycosylases / Q000235:genetics / Q000378:metabolism*; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair / Q000235:genetics*; D045643:DNA Repair Enzymes / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D000075223:Poly-ADP-Ribose Binding Proteins; D011485:Protein Binding; D011743:Pyrimidines / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D000075223:Poly-ADP-Ribose Binding Proteins; D011743:Pyrimidines; C039544:4,6-diamino-5-N-formamidopyrimidine; D004247:DNA; D045647:DNA Glycosylases; C473634:NEIL1 protein, human; D000251:Adenosine Triphosphatases; D004265:DNA Helicases; C078673:ERCC6 protein, human; C513075:Ercc6 protein, mouse; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D045643:DNA Repair Enzymes