title: Arabidopsis ZDP DNA 3'-phosphatase and ARP endonuclease function in 8-oxoG repair initiated by FPG and OGG1 DNA glycosylases.
abstract: Oxidation of guanine in DNA generates 7,8-dihydro-8-oxoguanine (8-oxoG), an ubiquitous lesion with mutagenic properties. 8-oxoG is primarily removed by DNA glycosylases distributed in two families, typified by bacterial Fpg proteins and eukaryotic Ogg1 proteins. Interestingly, plants possess both Fpg and Ogg1 homologs but their relative contributions to 8-oxoG repair remain uncertain. In this work we used Arabidopsis cell-free extracts to monitor 8-oxoG repair in wild-type and mutant plants. We found that both FPG and OGG1 catalyze excision of 8-oxoG in Arabidopsis cell extracts by a DNA glycosylase/lyase mechanism, and generate repair intermediates with blocked 3'-termini. An increase in oxidative damage is detected in both nuclear and mitochondrial DNA from double fpg ogg1 mutants, but not in single mutants, which suggests that a single deficiency in one of these DNA glycosylases may be compensated by the other. We also found that the DNA 3'-phosphatase ZDP (zinc finger DNA 3'-phosphoesterase) and the AP(apurinic/apyirmidinic) endonuclease ARP(apurinic endonuclease redox protein) are required in the 8-oxoG repair pathway to process the 3'-blocking ends generated by FPG and OGG1. Furthermore, deficiencies in ZDP and/or ARP decrease germination ability after seed deteriorating conditions. Altogether, our results suggest that Arabidopsis cells use both FPG and OGG1 to repair 8-oxoG in a pathway that requires ZDP and ARP in downstream steps.
authors.affiliation: Department of Genetics, University of Córdoba/Maimónides Institute for Research in Biomedicine of Córdoba (IMIBIC)/Reina Sofía University Hospital, 14071, Córdoba, Spain.
authors.forename: Dolores
authors.initials: D
authors.lastname: Córdoba-Cañero
authors.forename: Teresa
authors.initials: T
authors.lastname: Roldán-Arjona
authors.forename: Rafael R
authors.initials: RR
authors.lastname: Ariza
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage; D045647:DNA Glycosylases / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair; D004720:Endonucleases / Q000235:genetics / Q000378:metabolism*; D018525:Germination; D006147:Guanine / Q000031:analogs & derivatives / Q000378:metabolism; D016254:Mutagenesis, Insertional; D009708:Nucleotidases / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress; D012639:Seeds
chemical_list: C453560:7,8-dihydro-8-oxoguanine; D029681:Arabidopsis Proteins; C024829:8-hydroxyguanine; D006147:Guanine; C540283:Arp protein, Arabidopsis; D004720:Endonucleases; D009708:Nucleotidases; C039170:deoxynucleotide 3'-phosphatase; D045647:DNA Glycosylases; C500428:OGG1 protein, Arabidopsis
keywords: AP endonuclease; Arabidopsis thaliana; DNA glycosylase; DNA phosphatase; base-excision repair; oxidative DNA damage; seed vigor