Cockayne syndrome group B protein stimulates repair of formamidopyrimidines by NEIL1 DNA glycosylase

TY - JOUR

T1 - Cockayne syndrome group B protein stimulates repair of formamidopyrimidines by NEIL1 DNA glycosylase

AU - Muftuoglu, Meltem

AU - de Souza-Pinto, Nadja C

AU - Dogan, Arin

AU - Aamann, Maria

AU - Stevnsner, Tinna

AU - Rybanska, Ivana

AU - Kirkali, Güldal

AU - Dizdaroglu, Miral

AU - Bohr, Vilhelm A

PY - 2009/4

Y1 - 2009/4

N2 - 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.

AB - 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.

KW - Adenosine Triphosphatases

KW - Animals

KW - DNA

KW - DNA Glycosylases

KW - DNA Helicases

KW - DNA Repair

KW - DNA Repair Enzymes

KW - DNA-(Apurinic or Apyrimidinic Site) Lyase

KW - Hela Cells

KW - Humans

KW - Mice

KW - Mice, Knockout

KW - Protein Binding

KW - Pyrimidines

KW - Substrate Specificity

U2 - 10.1074/jbc.M807006200

DO - 10.1074/jbc.M807006200

M3 - Journal article

C2 - 19179336

SN - 0021-9258

VL - 284

SP - 9270

EP - 9279

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

IS - 14

ER -