Apn1 AP-endonuclease is essential for the repair of oxidatively damaged DNA bases in yeast frataxin-deficient cells.
Frataxin deficiency results in mitochondrial dysfunction and oxidative stress and it is the cause of the hereditary neurodegenerative disease Friedreich ataxia (FA). Here, we present evidence that one of the pleiotropic effects of oxidative stress in frataxin-deficient yeast cells (Δyfh1 mutant) is damage to nuclear DNA and that repair requires the Apn1 AP-endonuclease of the base excision repair pathway. Major phenotypes of Δyfh1 cells are respiratory deficit, disturbed iron homeostasis and sensitivity to oxidants. These phenotypes are weak or absent under anaerobiosis. We show here that exposure of anaerobically grown Δyfh1 cells to oxygen leads to down-regulation of antioxidant defenses, increase in reactive oxygen species, delay in G1- and S-phases of the cell cycle and damage to mitochondrial and nuclear DNA. Nuclear DNA lesions in Δyfh1 cells are primarily caused by oxidized bases and single-strand breaks that can be detected 15-30 min after oxygen exposition. The Apn1 enzyme is essential for the repair of the DNA lesions in Δyfh1 cells. Compared with Δyfh1, the double Δyfh1Δapn1 mutant shows growth impairment, increased mutagenesis and extreme sensitivity to H(2)O(2). On the contrary, overexpression of the APN1 gene in Δyfh1 cells decreases spontaneous and induced mutagenesis. Our results show that frataxin deficiency in yeast cells leads to increased DNA base oxidation and requirement of Apn1 for repair, suggesting that DNA damage and repair could be important features in FA disease progression.
Institut Jacques Monod, CNRS-Université Paris Diderot, Sorbonne Paris Cité, 15 rue Hélène Brion, 75205 Paris cedex 13, France.
Sophie
S
Lefevre
Caroline
C
Brossas
Françoise
F
Auchère
Nicole
N
Boggetto
Jean-Michel
JM
Camadro
Renata
R
Santos
D000477:Alkylating Agents / Q000494:pharmacology; D000693:Anaerobiosis; D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis; D059447:Cell Cycle Checkpoints; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004271:DNA, Fungal / Q000235:genetics* / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000502:physiology*; D005621:Friedreich Ataxia / Q000235:genetics; D015870:Gene Expression; D015966:Gene Expression Regulation, Fungal; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D033862:Iron-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D050296:Microbial Viability; D016296:Mutagenesis / Q000187:drug effects; D016877:Oxidants / Q000494:pharmacology; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D000096923:Frataxin
D000477:Alkylating Agents; D000975:Antioxidants; D045643:DNA Repair Enzymes; D004271:DNA, Fungal; D004272:DNA, Mitochondrial; D004706:Endodeoxyribonucleases; D005978:Glutathione; D006861:Hydrogen Peroxide; D033862:Iron-Binding Proteins; D008741:Methyl Methanesulfonate; D016877:Oxidants; D017382:Reactive Oxygen Species; D029701:Saccharomyces cerevisiae Proteins; D000096923:Frataxin; C083274:Apn1 protein, S cerevisiae