Moore S A
J Biol Chem. 1984 Jan 25;259(2):1004-10.
Saccharomyces cerevisiae MATa cells arrest cell division in response to the mating pheromone, alpha factor. After some interval of time the cells resume division. It is demonstrated here that cells recover from division arrest by becoming insensitive to the alpha factor under conditions of low cell density (10(2) cells/ml) where no alpha factor destruction occurs. The time of desensitization occurs later at higher alpha factor concentrations. Using the technique of perfusion photomicroscopy developed in this study, it was found that 95% of the desensitized cells remain insensitive to the alpha factor for greater than or equal to 3 generations at the alpha factor concentration where recovery occurred. Upon recovery, cells have generation times which are similar or identical to the calculated time from the cdc28 "start" step of cell division to cell separation. Therefore, the abnormally large recovered cells behave as if they have no growth time requirement for cell division for several generations. Desensitization was found to occur asymmetrically for parent and daughter cells. While parents (cells which have budded) are insensitive to alpha factor, their daughters (cells which have never budded and which were formed from desensitized parents during continuous perfusion with alpha factor) show 54% with a delayed generation time compared to control daughter cells.
酿酒酵母MATa细胞会因交配信息素α因子而停止细胞分裂。经过一段时间后，细胞会恢复分裂。本文证明，在低细胞密度（10²个细胞/毫升）且无α因子破坏的条件下，细胞通过对α因子变得不敏感从而从分裂停滞中恢复。脱敏时间在较高α因子浓度时出现得更晚。利用本研究中开发的灌注显微镜技术发现，在恢复时的α因子浓度下，95%的脱敏细胞对α因子的不敏感性持续≥3代。恢复后，细胞的世代时间与从细胞分裂的cdc28“起始”步骤到细胞分离的计算时间相似或相同。因此，异常大的恢复细胞在几代时间内表现得好像它们对细胞分裂没有生长时间要求。发现母细胞和子细胞的脱敏是不对称的。虽然母细胞（已出芽的细胞）对α因子不敏感，但它们的子细胞（从未出芽且在持续灌注α因子期间由脱敏母细胞形成的细胞）与对照子细胞相比，有54%的细胞世代时间延迟。
