Calorie Restriction-Mediated Life Span Extension in Yeast

描述(由申请人提供)：卡路里限制(CR)是一种延长多种生物最大寿命的饮食方案。CR还可以预防与衰老相关的疾病，包括II型糖尿病和癌症。有几种理论可以解释CR如何防止衰老的有害影响，但其分子机制尚未阐明。因此，目前老龄化研究的主要目标之一是了解CR是如何工作的，这将有助于确定未来预防或治疗年龄相关疾病的治疗靶点。值得注意的是，有一个酵母模型，它包括简单地将生长介质中的葡萄糖从2%降低到0.5%(或更少)，从而导致复制寿命(RLS)和时间顺序寿命(CLS)的延长，复制寿命(RLS)定义为母细胞可以分裂的次数，时间顺序寿命(CLS)定义为细胞在非分裂状态下存活的天数。Sir2是酵母RLS和卡路里限制的核心调节因子，但不是长寿或CR介导的CLS延长的关键调节因子。因此，该项目的长期目标是使用酵母CLS系统来鉴定和分子遗传学剖析新的CR介导的长寿途径。为了便于快速分析多个突变体和生长条件，对CLS分析进行了优化，可以同时处理-100个样品。该项目的具体目标首先集中在提纯和鉴定一种调节酵母寿命的胞外长寿因子。此外，我们建议利用高通量遗传筛选来识别在卡路里限制介导的CLS延伸中起作用的基因。最后一个特定的目标是解剖高度保守的从头合成嘌呤合成途径在调节CR反应的时间和复制寿命中的作用。考虑到酵母和人类细胞之间共享的大量基因和基本细胞过程，这项研究有望产生高度适用于哺乳动物CR研究的数据。

DESCRIPTION (provided by applicant): Calorie restriction (CR) is a dietary regimen that extends the maximum life span of a wide variety of organisms. CR also protects against aging-associated diseases, including type II diabetes and cancer. There are several theories to explain how CR protects against the detrimental effects of aging, but the molecular mechanism has yet to be elucidated. Therefore, one of the major goals of aging research at this time is to understand how CR works, which will help identify future therapeutic targets for the prevention or treatment of age-related disease. Remarkably, there is a yeast model of CR that consists of simply reducing the glucose in the growth medium from 2% to 0.5% (or less), which leads to an extension of replicative life span (RLS), defined as the number of times that a mother cell can divide, and chronological life span (CLS), defined as the number of days that cells survive in a non-dividing state. SIR2 is a central player in the regulation of yeast RLS and calorie restriction, but is not a key regulator of chronological longevity or CR-mediated extension of CLS. Therefore, the long-term goal of this project is to use the yeast CLS system for the identification and molecular-genetic dissection of novel CR-mediated longevity pathways. To facilitate rapid analysis of multiple mutants and growth conditions, the CLS assay has been optimized such that -100 samples can be processed at the same time. The specific aims of the project first focus on the purification and identification of an extracellular longevity factor that modulates yeast life span. In addition, we propose utilizing a high throughput genetic screen to identify genes that function in calorie restriction-mediated extension of CLS. The last specific aim is focused on dissecting the role of the highly conserved de novo purine synthesis pathway in modulating chronological and replicative life span in response to CR. Given the large number of genes and basic cellular processes shared between yeast and human cells, this study is expected to generate data that is highly applicable to CR research in mammals.