Genome-wide Analysis of Aging in Yeast

描述(申请人提供)：在过去的十年里，酵母已经成为研究真核细胞老化的一个广泛使用的模型系统。现已研制出两种分析方法。在复制试验中，一个细胞分裂并产生子细胞的次数被定义为其寿命。在年代学分析中，老化被定义为酵母细胞在非复制状态下保持活力的时间。虽然已有许多基因被报道影响酵母中的复制衰老或时间老化，但由于分析的困难，无法对酵母基因组进行完整的评估。此外，这两种酵母菌试验之间的关系还没有确定。通过技术开发、高通量机器的使用和熟练人力的应用，我们将获得时序(目标1)和复制(目标2)老化分析中整个非必需基因缺失集的定量读数。这一分析将使我们能够(1)确定影响其中一种老化试验的一组基因，(2)直接比较两种酵母老化试验，并将这些数据集与在线虫中进行的类似老化分析进行比较，(3)揭示调控酵母衰老的机制，以及(4)识别可能调节哺乳动物衰老的新途径。已经完成了对43个基因缺失或其他突变的初步分析，这些基因缺失或突变被报道为调节酵母的年代性或复制性衰老。此外，我们现在已经对所有(大约4900个)非必需酵母基因缺失菌株进行了半定量的时间老化分析。这一分析导致了TOR信号通路被确认为时序衰老的决定因素。我们对这些单基因缺失菌株和多基因缺失菌株的复制老化分析得出结论，热量限制可以通过Sir2不依赖于ERC的机制来延长酵母的复制寿命。到目前为止，已对12%的酵母非必需基因缺失进行了复制寿命分析，从而鉴定出13个新的调节复制寿命的衰老基因。其中最突出的是与TOR信号和核糖体功能有关的基因。目标3的一个主要焦点将是描述这一新的途径，以更好地理解热量限制延缓真核细胞衰老的机制。这项研究完成后，将极大地提高我们对酵母衰老的理解，并导致可以在哺乳动物系统中测试的卡路里限制模型。

DESCRIPTION (provided by applicant): Over the last decade, yeast has become a widely used model system to study eukaryotic aging. Two assays have been developed. In the replicative assay, the number of times that one cell can divide and produce daughter cells is defined as its life span. In the chronologic assay, aging is defined as the time a yeast cell can maintain viability in a non-replicative state. While many genes have been reported to affect replicative or chronologic aging in yeast, the difficulty of the assays has precluded a complete assessment of the yeast genome. Further, the relationship between the two yeast assays has not been determined. Through technology development, the use of high throughput machinery and the application of skilled manpower, we will derive quantitative readings for the entire non-essential gene deletion set in both the chronologic (Aim 1) and replicative (Aim 2) aging assays. This analysis will allow us to (1) identify the set of genes that affect either aging assay, (2) compare the two yeast aging assays directly and compare these data sets to a similar aging analysis performed in C. elegans, (3) uncover the mechanisms regulating yeast aging, and (4) identify new pathways that may regulate aging in mammals. A preliminary analysis of the 43 gene deletions or other mutations reported to regulate either yeast chronologic or replicative aging has been completed. In addition, we have now performed a semi-quantitative chronologic aging assay for all (approximately 4900) non-essential yeast gene deletion strains. This analysis has led to the identification of the TOR signaling pathway as a determinant in chronologic aging. Our analysis of replicative aging in these single gene deletion strains, and in strains with multiple deletions, has led to the conclusion that caloric restriction can extend yeast replicative life span by a SIR2-independent, ERC-independent mechanism. 12% of the yeast non-essential gene deletions have been analyzed for replicative life span to date, leading to the identification of 13 new aging genes regulating replicative life span. Prominent among these are genes implicated in TOR signaling and ribosome function. A major focus of Aim 3 will be to characterize this novel pathway to better understand the mechanisms by which caloric restriction delays eukaryotic aging. When completed, this study will dramatically improve our understanding of aging in yeast and lead to models of caloric restriction that can be tested in mammalian systems.