title: The cross talk between pathways in the repair of 8-oxo-7,8-dihydroguanine in mouse and human cells.
abstract: Although oxidatively damaged DNA is repaired primarily via the base excision repair (BER) pathway, it is now evident that multiple subpathways are needed. Yet, their relative contributions and coordination are still unclear. Here, mouse embryo fibroblasts (MEFs) from selected nucleotide excision repair (NER) and/or BER mouse mutants with severe (Csb(m/m)/Xpa(-/-) and Csb(m/m)/Xpc(-/-)), mild (Csb(m/m)), or no progeria (Xpa(-/-), Xpc(-/-), Ogg1(-/-), Csb(m/m)/Ogg1(-/-)) or wild-type phenotype were exposed to an oxidizing agent, potassium bromate, and genomic 8-oxo-7,8-dihydroguanine (8-oxoGua) levels were measured by HPLC-ED. The same oxidized DNA base was measured in NER/BER-defective human cell lines obtained after transfection with replicative plasmids encoding siRNA targeting DNA repair genes. We show that both BER and NER factors contribute to the repair of 8-oxoGua, although to different extents, and that the repair profiles are similar in human compared to mouse cells. The BER DNA glycosylase OGG1 dominates 8-oxoGua repair, whereas NER (XPC, XPA) and transcription-coupled repair proteins (CSB and CSA) are similar, but minor contributors. The comparison of DNA oxidation levels in double versus single defective MEFs indicates increased oxidatively damaged DNA only when both CSB and XPC/XPA are defective, indicating that these proteins operate in different pathways. Moreover, we provide the first evidence of an involvement of XPA in the control of oxidatively damaged DNA in human primary cells.
authors.affiliation: Department of Environment and Primary Prevention, Istituto Superiore di Sanità, 00161 Rome, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Parlanti
authors.forename: Mariarosaria
authors.initials: M
authors.lastname: D'Errico
authors.forename: Paolo
authors.initials: P
authors.lastname: Degan
authors.forename: Angelo
authors.initials: A
authors.lastname: Calcagnile
authors.forename: Andrea
authors.initials: A
authors.lastname: Zijno
authors.forename: Ingrid
authors.initials: I
authors.lastname: van der Pluijm
authors.forename: Gijsbertus T J
authors.initials: GT
authors.lastname: van der Horst
authors.forename: Denis S F
authors.initials: DS
authors.lastname: Biard
authors.forename: Eugenia
authors.initials: E
authors.lastname: Dogliotti
mesh_terms: D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D004249:DNA Damage; D045647:DNA Glycosylases / Q000378:metabolism; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D051379:Mice; D018345:Mice, Knockout; D010084:Oxidation-Reduction; D000075223:Poly-ADP-Ribose Binding Proteins; D013045:Species Specificity; D051760:Xeroderma Pigmentosum Group A Protein / Q000235:genetics / Q000378:metabolism / Q000502:physiology
chemical_list: D004268:DNA-Binding Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; C497314:XPA protein, human; D051760:Xeroderma Pigmentosum Group A Protein; C501002:Xpc protein, mouse; C024829:8-hydroxyguanine; D006147:Guanine; D045647:DNA Glycosylases; C485990:Ogg1 protein, mouse; C513075:Ercc6 protein, mouse; D045643:DNA Repair Enzymes