Ionizing radiation induces a Yap1-dependent peroxide stress response in yeast.
Repair of DNA damage is fundamental for cellular tolerance to ionizing radiation (IR) and many IR-induced DNA lesions are thought to occur as a result of oxidative stress. We investigated the physiological effects of IR in Saccharomyces cerevisiae by performing protein expression profiles in cells exposed to electron pulse irradiation. Transient induction of several antioxidant enzymes in wild-type cells, but not in cells lacking the oxidative stress regulator Yap1, indicated that IR exposure causes cellular oxidative stress. Yap1 activation involved oxidation to the intramolecular disulfide bond, a signature of activation by peroxide, and was dependent on the Yap1 peroxide sensor Orp1/Gpx3. H(2)O(2) was produced in the culture medium of irradiated cells and was both necessary and sufficient for IR-induced Yap1 activation. When IR was performed in the presence of N(2)O, obviating H(2)O(2) production and increasing hydroxyl radical ((*)OH) production, the Yap1 response was lost, indicating that Yap1 was unable to respond to (*)OH or (*)OH-induced damage. However, the Yap1 response to IR did not seem to be a primary determinant of cellular IR tolerance. Altogether, these data provide a molecular demonstration that cells experience in vivo peroxide stress during IR and indicate that the H(2)O(2) produced cannot account for IR toxicity.
Molin
Mikael
M
Laboratoire de PhysioGénomique, SBGM/DBJC/DSV, CEA/Saclay, F-91191, Gif-sur-Yvette Cedex, France.
Renault
Jean-Philippe
JP
Lagniel
Gilles
G
Pin
Serge
S
Toledano
Michel
M
Labarre
Jean
J
D000975:Antioxidants / Q000494:pharmacology; D004268:DNA-Binding Proteins; D006861:Hydrogen Peroxide / Q000378:metabolism*; D009589:Nitrogen Oxides / Q000633:toxicity; D018384:Oxidative Stress / Q000528:radiation effects*; D010545:Peroxides / Q000633:toxicity; D040081:Protein Array Analysis; D011839:Radiation, Ionizing; D012262:Ribonucleoside Diphosphate Reductase / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
D000975:Antioxidants; D004268:DNA-Binding Proteins; C081935:MSN2 protein, S cerevisiae; C081937:MSN4 protein, S cerevisiae; D009589:Nitrogen Oxides; D010545:Peroxides; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C086677:YAP1 protein, S cerevisiae; D013481:Superoxides; C010125:nitrogen pentoxide; D006861:Hydrogen Peroxide; D012262:Ribonucleoside Diphosphate Reductase; C523202:Rnr4 protein, S cerevisiae