Ashrafi K, Sinclair D, Gordon J I, Guarente L
Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Proc Natl Acad Sci U S A. 1999 Aug 3;96(16):9100-5. doi: 10.1073/pnas.96.16.9100.
Saccharomyces cerevisiae mother cells undergo an aging program that includes morphologic changes, sterility, redistribution of the Sir transcriptional silencing complex from HM loci and telomeres to the nucleolus, alterations in nucleolar architecture, and accumulation of extrachromosomal ribosomal DNA circles (ERCs). We report here that cells starved for nutrients during prolonged periods in stationary phase show a decrease in generational lifespan when they reenter the cell cycle. This shortened lifespan is not transmitted to progeny cells, indicating that it is not due to irreversible genetic damage. The decrease in the lifespan is accompanied by all of the changes of accelerated aging with the notable exception that ERC accumulation is not augmented compared with generation-matched, nonstarved cells. These results suggest a number of models, including one in which starvation reveals a component of aging that works in parallel with the accumulation of ERCs. Stationary-phase yeast cells may be a useful system for identifying factors that affect aging in other nondividing eukaryotic cells.
酿酒酵母母细胞会经历一个衰老程序，其中包括形态变化、不育、Sir转录沉默复合物从HM位点和端粒重新分布到核仁、核仁结构改变以及染色体外核糖体DNA环（ERC）的积累。我们在此报告，在稳定期长期缺乏营养的细胞在重新进入细胞周期时，其代际寿命会缩短。这种缩短的寿命不会传递给子代细胞，这表明它不是由于不可逆的遗传损伤所致。寿命的缩短伴随着加速衰老的所有变化，但值得注意的是，与代际匹配的未饥饿细胞相比，ERC积累并未增加。这些结果提出了多种模型，其中一种模型认为饥饿揭示了衰老的一个组成部分，该部分与ERC的积累并行起作用。稳定期酵母细胞可能是一个有用的系统，用于识别影响其他非分裂真核细胞衰老的因素。
