Mitochondrial Genetics of Aging in Drosophila

描述（由申请人提供）：衰老的主要原因被认为是线粒体中作为氧化磷酸化（OXPHOS）副产物产生的活性氧（ROS）。增加ROS清除或减少ROS产生的操作在一些但不是所有系统中延长了寿命。热量或饮食限制（CR或DR）仍然是迄今为止研究的所有生物体中延长寿命的最可重复的干预措施。最近的研究已经确定了CR或DR、线粒体功能改变和寿命延长之间的关系。在这个提议中，我们提出了明确的证据，证明mtDNA单倍型1）可以延长或缩短寿命，2）修改饮食限制的长寿效应，3）修改胰岛素受体底物突变chico 1的长寿效应。这些发现提供了核-mtDNA上位性作图在揭示通过饮食限制延长寿命的遗传机制方面有效的原则证据。这些结果导致了这样一种假设，即mtDNA中编码的基因对营养依赖的长寿修饰至关重要。我们将利用这些mtDNA替代菌株来测试这一假设，使用上位性实验与Rpd 3-Sir 2和TOR途径，发挥重要作用的营养为基础的长寿变化。这些遗传结构也将被用来检验mtDNA基因型通过改变氧化损伤水平来改变寿命的一般假设。有三个具体的目标将测试这些假设：1）mtDNA基因型是否改变Rpd 3依赖的寿命延长？我们将检验线粒体基因改变Rpd 3对寿命的影响的假设，以及Rpd 3与DR的独立性。2）mtDNA基因型是否改变了Sir 2依赖的饮食限制效应？我们将测试的假设，mtDNA基因型修改的作用Sir 2在调节DR的反应，通过配对的mtDNA与过表达和组织特异性表达构建不同的饮食。3)mtDNA基因型是否改变了TOR通路对营养感受和寿命延长的影响？我们将通过将mtDNA与这些基因的亚型和组织特异性表达构建体配对来检验mtDNA基因型改变TOR和Tsc 2在延长寿命中发挥的作用的假设。公共卫生相关性：这些实验将提供关于特定线粒体基因组如何与定义的核基因相互作用以确定寿命和寿命的饮食调节的基本信息。由于这些相互作用在进化上是古老的和高度保守的，因此解剖影响果蝇衰老的遗传途径将与理解人类的衰老和与年龄相关的疾病非常相关。

DESCRIPTION (provided by applicant): A primary cause of aging is thought to be reactive oxygen species (ROS) produced in mitochondria as byproducts of oxidative phosphorylation (OXPHOS). Manipulations that either increase ROS scavenging or decrease ROS production have extended longevity in some, but not all systems. Caloric or dietary restriction (CR or DR) remains the single most repeatable intervention that extends longevity in all organisms studied to date. Recent studies have identified a relationship between CR or DR, altered mitochondrial function, and extended longevity. In this proposal we present clear evidence that mtDNA haplotypes 1) can extend or shorten longevity, 2) modify the longevity-extending effects of diet restriction, 3) modify the longevity-extending effects of the insulin receptor substrate mutation chico1. These findings provide proof of principle that nuclear-mtDNA epistasis mapping is effective in uncovering genetic mechanisms of longevity extension by diet restriction. The results lead to the hypothesis that genes encoded in mtDNA are critical for the nutrient-dependent modification of longevity. We will exploit these mtDNA replacement strains to test this hypothesis using epistasis experiments with the Rpd3 - Sir2 and TOR pathways that play important roles in nutrient-based changes in longevity. These genetic constructs will also be used to test the general hypothesis that mtDNA genotype modifies longevity through changes in the level of oxidative damage. There are three specific aims that will test each of these hypotheses: 1) Does mtDNA genotype alter the Rpd3-dependent extension of longevity? We will test the hypothesis that mitochondrial genes modify the effect of Rpd3 on longevity, and Rpd3's independence from DR. 2) Does mtDNA genotype alter the Sir2-dependent effects of dietary restriction? We will test the hypothesis that mtDNA genotype modifies the role Sir2 plays in regulating the response to DR by pairing mtDNAs with over-expression and tissue specific expression constructs on different diets. 3) Does mtDNA genotype modify the TOR pathway effects on nutrient sensing and longevity extension? We will test the hypothesis that mtDNA genotype modifies the role that TOR and Tsc2 play in extending longevity by pairing mtDNAs with hypomorphic and tissue specific expression constructs of these genes. PUBLIC HEALTH RELEVANCE: These experiments will provide fundamental information on how specific mitochondrial genomes interact with defined nuclear genes to determine longevity and the dietary modulation of longevity. As these interactions are evolutionarily ancient and highly conserved, the dissection of genetic pathways affecting aging in Drosophila will be very relevant to understanding this aging and age-related diseases in humans.