抄録
We have analyzed delayed mutation as part of cellular response to genotoxic damage and found that this occurs at the pink-eyed unstable locus in the somatic cells of F1 mice born to irradiated sperm. However, a whole body mouse system and tissue culture cells are too complex to elucidate the molecular mechanism of delayed mutation.We have now examined delayed mutation in fission yeast. We have constructed three yeast strains which carry tandem duplications differing in length at the ura4 gene. These loci revert to the wild type (WT) through homologous recombination (HR). The frequency of spontaneous HR was linearly related to the length of the repeat. One of the strains carrying a 200 bp repeat unit was used and the frequency of the reversion was found to be dependent on the dose of X-ray to the cells (25-500 Gy). In addition, higher mutation frequencies persisted for 6-10 cell generations after irradiation where damage repair was thought to have been completed.These results suggest that untargeted mutation and delayed mutation is induced in fission yeast by damage to the genome.
