GENES AFFECTING METABOLISM AND LONGEVITY IN C. ELEGANS

四个数量性状基因座(QTL)通过遗传作图发现，并通过重组缩小范围，影响线虫的成虫寿命和一个或多个胁迫反应。每个菌株在基因组上与亲本菌株有1-3%的差异，但在这些表型上与亲本菌株有显著的重复性差异。此外，目前在线虫中已知47个基因座，据报道突变可延长寿命，还有两个 饮食干预(卡路里限制和辅酶Q缺乏)显著延长了野生型菌株和一些突变株的寿命。我们建议同时研究这四个新的QTL，以及两个修改的饮食和一个由14个突变菌株(代表所有类别的突变，相对于适当的对照延长1.5-3.8-Tbld的寿命)组成的“长寿小组”，以寻找一系列表明它们的代谢和抗氧化状态的指标。其具体目的是(1)通过选择和测试分割QTL的重组子来缩小所涉及的QTL区间。(2) 评估每个长寿基因座和一组长寿突变体和饮食(有对照)的多种表型：特征包括对氧化和其他应激的抵抗力、代谢活动(O2消耗；二氧化碳和NH3的产生)和终生代谢输出，以及寿命作为卡路里摄入量的函数。(3)评估这些基因座的分子表型，包括(A)代谢谱，以测量自由基的产生和损伤指数(对于同源系和长寿组)，以及(B)基因芯片评估的Genc-cxprssion谱。(4)通过下列终局策略评估和确认候选基因的功能：(A)通过转基因过表达或RNAi抑制，使转录水平显著不同的等位基因的表型逆转：(B)基于图谱，对已知具有等位基因多态以延长寿命的五个菌株的候选基因的外显子进行测序；(C)对于通过转座子插入而不同的等位基因，筛选通过精确的种系产生的反转变种。 (D)通过挽救酵母基因敲除菌株进行功能测定。同时影响寿命和新陈代谢损伤的遗传变异在进化过程中可能是保守的，因此将在其他模式生物中进行评估。这种比较分子老年学策略可能导致发现影响人类寿命和年龄相关疾病的途径，从而减轻老年人的疾病和虚弱。

Four quantitative trait loci (QTLs), discovered by genetic mapping and narrowed through recombination, affect both adult longevity and one or more stress responses in the nematode C. elegans. Each strain differs genetically from the parental strain by 1-3% of the genome, yet differs from it reproducibly and significantly in these phenotypes. In addition, 47 loci are presently known in C. elegans, at which mutations have been reported to extend life, and two dietary interventions (caloric restriction and CoQ deficiency) markedly increase the life spans of wild type strains and some mutants. We propose to study these four new QTLs in parallel with two modified diets and a "longevity panel" of 14 mutant strains (representing all classes of mutation that confer 1.5- to 3.8-tbld life-extension relative to appropriate controls), for an array of measures indicating their metabolic and antioxidant status. The Specific Aims are to (1) Narrow the implicated QTL intervals by selecting and testing recombinants that partition them. (2) Assess multiple in rive phenotypes for each longevity locus and the panel of long-lived mutants and diets (with controls): traits include rcsistance to oxidative and other stresses, metabolic activity (02 consumption; production of CO2 and NH3) and lifetime metabolic output, and life span as a function of caloric intake. (3) Assess molecular phenotypes of these loci, including (a) metabolic profiles to measure indices of free radical generation and damage (for the congenic lines and also for the longevity panel), and (b) genc-cxprcssion profiles assessed on microarrays. (4) Assess and confirm candidate-gene functions by the following end-game strategies: (a) phenotypic reversion through transgenic overexpression or RNAi suppression, for alleles differing markedly in transcript levels: (b) sequencing exons of candidate gene in five strains known to harbor allelic polymorphisms for longevity based on mapping; (c) for alleles differing by a transposon insertion, screening for revertants that arise by precise germline excision; and (d) functional assay by rescue of yeast knock-out strains. Genetic variants that affect both longevity and metabolic damage are likely to be conserved in evolution, and will therefore be evaluated in other model organisms. This comparative molecular gerontology strategy may lead to discovery of pathways affecting life span and age-associated diseases in humans, and thus to the alleviation of illness and debility among the aged.