Davies P J, Tippins R S, Parry J M
Mutat Res. 1978 Sep;51(3):327-46. doi: 10.1016/0027-5107(78)90122-7.
Exponentially growing yeast cultures separated into discrete periods of the cell cycle by zonal rotor centrifugation show cyclic variation in both UV and nitrous acid induced cell lethality, mitotic gene conversion and mitotic crossing-over. Maximum cell survival after UV treatment was observed in the S and G2 phases of the cell cycle at a time when UV induction of both types of mitotic recombination was at a minimum. In contrast, cell inactivation by the chemical mutagen nitrous acid showed a single discrete period of sensitivity which occurred in S phase cells which are undergoing DNA synthesis. Mitotic gene conversion and mitotic crossing-over were induced by nitrous acid in cells at all stages of the cell cycle with a peak of induction of both events occurring at the time of maximum cell lethality. The lack of correlation observed between maximum cell and the maximum induction of mitotic intragenic recombination suggest that other DNA-repair mechanisms besides DNA-recombination repair are involved in the recovery of inactivated yeast cells during the cell cycle.
通过区带转子离心将指数生长的酵母培养物分离到细胞周期的不同阶段，结果显示紫外线和亚硝酸诱导的细胞致死率、有丝分裂基因转换和有丝分裂交换均呈现周期性变化。在细胞周期的S期和G2期观察到紫外线处理后细胞存活率最高，此时两种类型的有丝分裂重组的紫外线诱导率最低。相比之下，化学诱变剂亚硝酸导致的细胞失活表现出一个单一的离散敏感时期，该时期出现在正在进行DNA合成的S期细胞中。在细胞周期的所有阶段，亚硝酸均可诱导有丝分裂基因转换和有丝分裂交换，这两种事件的诱导峰值均出现在细胞致死率最高之时。在最大细胞存活率与有丝分裂基因内重组的最大诱导率之间观察到缺乏相关性，这表明除了DNA重组修复之外，其他DNA修复机制也参与了细胞周期中失活酵母细胞的恢复过程。
