Chen Bo-Ruei, Runge Kurt W
Department of Genetics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA,
Subcell Biochem. 2012;57:291-314. doi: 10.1007/978-94-007-2561-4_13.
Yeasts are powerful model systems to examine the evolutionarily conserved aspects of eukaryotic aging because they maintain many of the same core cellular signaling pathways and essential organelles as human cells. We constructed a strain of the budding yeast Saccharomyces cerevisiae that could monitor the distribution of proteins involved in heterochromatic silencing and aging, and isolated mutants that alter this distribution. The largest class of such mutants cause defects in mitochondrial function, and appear to cause changes in nuclear silencing separate from the well-known Rtg2p-dependent pathway that alters nuclear transcription in response to the loss of the mitochondrial genome. Mutants that inactivate the ATP2 gene, which encodes the ATPase subunit of the mitochondrial F(1)F(0)-ATPase, were isolated twice in our screen and identify a lifespan extending pathway in a gene that is conserved in both prokaryotes and eukaryotes. The budding yeast S. cerevisiae S. cerevisiae has been used with great success to identify other lifespan-extending pathways in screens using surrogate phenotypes such as stress resistance or silencing to identify random mutants, or in high throughput screens that utilize the deletion strain set resource. However, the direct selection of long-lived mutants from a pool of random mutants is more challenging. We have established a new chronological aging assay for the evolutionarily distant fission yeast Schizosaccharomyces pombe that recapitulates aspects of aging conserved in all eukaryotes. We have constructed a novel S. pombe S. pombe DNA insertion mutant bank, and used it to show that we can directly select for a long-lived mutant. The use of both the budding and fission yeast systems should continue to facilitate the identification and validation of lifespan extending pathways that are conserved in humans.
酵母是研究真核生物衰老进化保守方面的强大模型系统，因为它们维持着许多与人类细胞相同的核心细胞信号通路和重要细胞器。我们构建了一种芽殖酵母酿酒酵母菌株，该菌株可以监测参与异染色质沉默和衰老的蛋白质的分布，并分离出改变这种分布的突变体。这类突变体中最大的一类会导致线粒体功能缺陷，并且似乎会引起核沉默的变化，这与众所周知的Rtg2p依赖性途径不同，后者会因线粒体基因组的缺失而改变核转录。在我们的筛选中，两次分离出使ATP2基因失活的突变体，该基因编码线粒体F(1)F(0)-ATP酶的ATP酶亚基，这在一个原核生物和真核生物中都保守的基因中确定了一条延长寿命的途径。芽殖酵母酿酒酵母已成功用于通过使用诸如抗逆性或沉默等替代表型来鉴定随机突变体的筛选中，或在利用缺失菌株集资源的高通量筛选中鉴定其他延长寿命的途径。然而，从随机突变体库中直接选择长寿突变体更具挑战性。我们为进化上较远的裂殖酵母粟酒裂殖酵母建立了一种新的时序衰老测定法，该方法概括了所有真核生物中保守的衰老方面。我们构建了一个新的粟酒裂殖酵母DNA插入突变体库，并用它来表明我们可以直接选择长寿突变体。芽殖酵母和裂殖酵母系统的使用应继续促进对人类中保守的延长寿命途径的鉴定和验证。
