Filipak M, Drebot M A, Ireland L S, Singer R A, Johnston G C
Department of Microbiology, Dalhousie University, Halifax, Nova Scotia, Canada.
Curr Genet. 1992 Dec;22(6):471-7. doi: 10.1007/BF00326412.
Double-mutant cells of the budding yeast Saccharomyces cerevisiae harboring the gcs1-1 and sed1-1 mutations are conditionally defective (cold-sensitive) only for reentry into the mitotic cycle from stationary phase. If already proliferating at the permissive temperature (29 degrees C), these reentry-mutant cells continue to proliferate when transferred to the restrictive temperature of 14 degrees C, but under these conditions reentry-mutant cells lose mitochondrial DNA (mtDNA). In addition, upon exhaustion of the nutrient supply at 14 degrees C, these reentry-mutant cells entered stationary phase at a decreased cell concentration and did not accumulate the reserve carbohydrates trehalose and glycogen. Both of these deficiencies were due to the loss of mtDNA, as shown by the responses of wild-type cells also lacking mtDNA. Mitochondrial status did not affect other aspects of the reentry-mutant phenotype. Although mitochondrial activity and the accumulation of carbohydrate reserves are typical features of cells in stationary phase, the reentry-mutant phenotype reveals that neither entry into nor exit from stationary phase need involve mitochondrial function.
携带gcs1-1和sed1-1突变的出芽酵母酿酒酵母双突变细胞仅在从静止期重新进入有丝分裂周期时存在条件性缺陷（冷敏感）。如果在允许温度（29摄氏度）下已经在增殖，这些重新进入突变细胞在转移到14摄氏度的限制温度时会继续增殖，但在这些条件下，重新进入突变细胞会丢失线粒体DNA（mtDNA）。此外，在14摄氏度营养供应耗尽时，这些重新进入突变细胞以降低的细胞浓度进入静止期，并且不会积累储备碳水化合物海藻糖和糖原。正如缺乏mtDNA的野生型细胞的反应所示，这两种缺陷都是由于mtDNA的丢失。线粒体状态不影响重新进入突变体表型的其他方面。尽管线粒体活性和碳水化合物储备的积累是静止期细胞的典型特征，但重新进入突变体表型表明，进入或退出静止期都不一定涉及线粒体功能。
