A functional OGG1 homologue from Arabidopsis thaliana.
One of the major mutagenic base lesions in DNA caused by exposure to reactive oxygen species is 7,8-dihydro-8-oxoguanine (8-oxoG). Genes coding for DNA repair enzymes that recognise 8-oxoG have been reported in bacteria, yeast, mammals and plants. The prokaryotic and eukaryotic genes are functional homologues but differ in their primary sequence. We have cloned, sequenced, and expressed a new Arabidopsis thaliana cDNA that shows sequence homology to the eukaryotic genes coding for 8-oxoG DNA N-glycosylases (OGG1). The 40.3-kDa enzyme it encodes (AtOGG1) introduces a chain break in a double-stranded oligonucleotide specifically at an 8-oxoG residue. In addition, AtOGG1 can form a Schiff base with 8-oxoG in the presence of NaBH4, suggesting that it is a bifunctional DNA N-glycosylase. Furthermore, expression of AtOGG1 in an Escherichia coli strain that is deficient in the repair of 8-oxoG in DNA suppresses its spontaneous-mutator phenotype. Thus, we have demonstrated that AtOGG1 is not only a structural but also a functional eukaryotic OGG1 homologue.
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CEA/Cadarache, DSV, DEVM, Laboratoire de Radiobiologie Végétale, Saint Paul-lez-Durance, France.
Tissier
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D017398:Alternative Splicing; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D001483:Base Sequence; D045647:DNA Glycosylases; D018744:DNA, Plant / Q000378:metabolism; D043382:DNA-Formamidopyrimidine Glycosylase; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins; D017343:Genes, Plant; D006801:Humans; D008969:Molecular Sequence Data; D009699:N-Glycosyl Hydrolases / Q000235:genetics* / Q000502:physiology; D018384:Oxidative Stress; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D018744:DNA, Plant; D029968:Escherichia coli Proteins; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; C061738:mutY adenine glycosylase; D043382:DNA-Formamidopyrimidine Glycosylase; C468610:DNA-formamidopyrimidine glycosylase, E coli