Control of Yeast Life Span

描述（由申请人提供）：人类衰老的标志之一是线粒体功能随着年龄的增长而下降。模型系统已经证明了一个信号通路，该信号通路将线粒体的功能状态传递给细胞核，以协调转录反应。利用一个独特的监测核转录变化的报告系统，我们发现了一个新的线粒体-核信号通路，揭示了在酿酒酵母中由ATP2基因编码的F1F0-ATP合成酶复合物的b亚基的重要性。我们发现缺乏ATP2基因的细胞寿命较短，这是令人惊讶的，因为在秀丽隐杆线虫的RNAi实验表明，减少其他F1F0- ATP合成酶亚基的表达可以延长寿命。我们取得了令人兴奋的发现，适度减少或增加ATP2表达可以延长酿酒葡萄球菌的寿命。我们假设b亚基水平的错误调节会导致ATP水平的降低。由于F1F0-ATP合成酶从细菌到人类都是保守的，了解它是如何延长酵母寿命的，以及这种作用是否在进化上是保守的，将对我们对衰老的理解产生广泛的影响。为了确定其他的长寿途径，我们在裂糖酵母中开发了一种新的衰老测定方法，该方法概括了长寿细胞通过限制热量和抗逆性延长寿命的进化保守特性。这种试验允许从随机突变体种群中直接和公正地选择长寿突变体。我们已经建立了一个大型的S. pombe DNA插入突变体库，这将允许分离长寿命突变体和快速鉴定受影响的基因。我们的长期目标是了解控制衰老的遗传途径，我们将通过描述模型系统中进化保守的途径来实现这一目标。我们的具体目标将回答以下问题：1。突变体F1F0-ATP合成酶b亚基的寿命延长是否与产生ATP能力的降低有关？我们将确定长寿突变体是否改变了ATP水平和线粒体功能，并测试b亚基是否必须定位于线粒体才能延长寿命。2. 错误调节F1F0-ATP合成酶b亚基的延长寿命效应是否具有进化保守性？我们将测试错误调节b亚基是否会增加果蝇或S. pombe的寿命。3. 在我们独特的S. pombe衰老试验中，公正地分离长寿突变体是否揭示了延长按时间顺序寿命的新途径？我们将通过热量限制来描述S. pombe延长寿命的机制，并利用这一系统来识别新的延长寿命的突变。我们的研究结果将为进化保守途径提供新的见解，这将影响对人类衰老生物学的理解。公共卫生相关性：人体内的所有细胞都依赖线粒体产生能量并进行生命所需的各种过程。用酵母作为人类细胞的模型，我们发现线粒体蛋白的少量增加可以延长20%的寿命。我们还发现了一种方法，可以发现许多延长酵母寿命的新突变，这些突变可以揭示延长人类细胞寿命的类似方法。

DESCRIPTION (provided by applicant): One of the hallmarks of human aging is the decline in mitochondrial function with advancing years. Model systems have demonstrated a signaling pathway that communicates the functional state of the mitochondria to the nucleus to coordinate a transcriptional response. Using a unique reporter system that monitors changes in nuclear transcription, we uncovered a new mitochondrial-nuclear signaling pathway that revealed the importance of the b-subunit of the F1F0-ATP synthase complex, encoded in Saccharomyces cerevisiae by the ATP2 gene. We found that cells lacking the ATP2 gene had a short lifespan, which was surprising since RNAi experiments in Caenorhabditis elegans indicated that reducing expression of other F1F0- ATP synthase subunits extends lifespan. We made the exciting discovery that either a modest decrease or increase in ATP2 expression extends S. cerevisiae lifespan. We hypothesize that misregulation of b-subunit levels causes a decrease in ATP levels. As the F1F0-ATP synthase is conserved from bacteria to humans, understanding how it can extend yeast lifespan and if this effect is evolutionarily conserved will have wide impact on our understanding of aging. To identify additional longevity pathways, we developed a new aging assay in Schizosaccharomyces pombe that recapitulates the evolutionarily conserved properties of lifespan extension by caloric restriction and stress resistance of long-lived cells. This assay allows the direct and unbiased selection of long-lived mutants from populations of random mutants. We have constructed a large bank of S. pombe DNA insertion mutants that will allow an isolation of long-lived mutants and rapid identification of the affected genes. Our long-term goals are to understand the genetic pathways that control aging, which we will approach by characterizing evolutionarily conserved pathways in model systems. Our specific aims will answer the following questions: 1. Is the lifespan extension of mutants misregulated in the F1F0-ATP synthase b-subunit related to a reduction in the ability to produce ATP? We will determine if the long-lived mutants have altered ATP levels and mitochondrial functions, and test whether the b-subunit must be localized to mitochondria to extend lifespan. 2. Are the lifespan extending effects of misregulating the b-subunit of the F1F0-ATP synthase evolutionarily conserved? We will test if misregulating the b-subunit increases Drosophila or S. pombe lifespan. 3. Does the unbiased isolation of long-lived mutants in our unique S. pombe aging assay reveal new pathways to extend chronological lifespan? We will characterize the mechanism of lifespan extension in S. pombe by caloric restriction and use this system to identify new lifespan extending mutations. Our results will provide new insights into evolutionarily conserved pathways that will impact the understanding of the biology of human aging. PUBLIC HEALTH RELEVANCE: All cells in the human body rely on mitochondria to produce energy and to carry out a wide variety of processes required for life. Using yeast as a model for human cells, we found that a small increase in a mitochondrial protein can increase lifespan by 20%. We have also discovered a way to find many new mutations that prolong life in yeast that can reveal similar ways to prolong life in human cells.