Mutation of budding yeast induced by ion beam irradiation

Izumi, Yoshinobu*; Matsuo, Yoichiro*; Sakamoto, Ayako; Takagi, Keiichi*; Hatashita, Masanori*; Kojima, Takao*; Shimizu, Kikuo*

In cases of ion-beam irradiations, several features of deep interest can be observed, contrasting with the low-LET radiations such as -rays. In order to elucidate the induction mechanisms of mutations peculiar to ion beams, carbon-ion beams with LETs of 13 keV/m - 107 keV/m and proton beam with LET of 0.45 keV/m were irradiated to budding yeast. Carbon-ion beams and proton beam irradiation were performed in TIARA or HIMAC, and WERC, respectively. After irradiations, survival ratios and mutation frequencies were analyzed as well as sequencing and gene expression analyses. In order to elucidate the molecular mechanisms of mutagenesis caused by radiations, we used (BER-) which is deficient in the elimination of 8-oxodGTP and (MMR-) deficient in the mismatch-repair function. For comparison, we also used (NHEJ-) and (HR-) that were deficient in the double-strand breaks (DSBs)-repair function.