Defective repair of 5-hydroxy-2'-deoxycytidine in Cockayne syndrome cells and its complementation by Escherichia coli formamidopyrimidine DNA glycosylase and endonuclease III.
Repair of the oxidized purine 8-oxo-7,8-dihydro-2'-deoxyguanosine is inefficient in cells belonging to both complementation groups A and B of Cockayne syndrome (CS), a developmental and neurological disorder characterized by defective transcription-coupled repair. We show here that both CS-A and CS-B cells are also defective in the repair of 5-hydroxy-2'-deoxycytidine (5-OHdC), an oxidized pyrimidine with cytotoxic and mutagenic properties. The defect in the repair of oxidatively damaged DNA in CS cells thus extends to oxidized pyrimidines, indicating a general flaw in the repair of oxidized lesions in this syndrome. The defect could not be reproduced in in vitro repair experiments on oligonucleotide substrates, suggesting a role for both CS-A and CS-B proteins in chromatin remodeling during 5-OHdC repair. Expression of Escherichia coli formamidopyrimidine DNA glycosylase (FPG) or endonuclease III complemented the 5-OHdC repair deficiency. Hence, the expression of a single enzyme, FPG from E. coli, stably corrects the delayed removal of both oxidized purines and oxidized pyrimidines in CS cells.
Foresta
Mara
M
Molecular Mutagenesis and DNA Repair, Istituto Nazionale Ricerca Cancro, 16132 Genova, Italy.
Ropolo
Monica
M
Degan
Paolo
P
Pettinati
Ilaria
I
Kow
Yoke W
YW
Damonte
Gianluca
G
Poggi
Alessandro
A
Frosina
Guido
G
D000293:Adolescent; D000369:Aged, 80 and over; D002461:Cell Line, Transformed; D002675:Child, Preschool; D042002:Chromatin Assembly and Disassembly / Q000235:genetics; D003057:Cockayne Syndrome / Q000235:genetics / Q000378:metabolism* / Q000628:therapy; D049914:DNA Repair-Deficiency Disorders / Q000235:genetics; D043382:DNA-Formamidopyrimidine Glycosylase / Q000235:genetics / Q000378:metabolism*; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000378:metabolism; D043224:Deoxyribonuclease (Pyrimidine Dimer) / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D014162:Transfection
D029968:Escherichia coli Proteins; D003841:Deoxycytidine; C074071:5-hydroxy-2'-deoxycytidine; D043224:Deoxyribonuclease (Pyrimidine Dimer); C106403:NTH protein, E coli; D043382:DNA-Formamidopyrimidine Glycosylase