Genomic analysis of C. elegans fat regulatory pathways

描述(申请人提供)：从遗传分析和RNAi筛选的组合中，我们发现了数百个基因失活和突变，有望揭示线虫脂肪储存设定点的神经内分泌回路。由于RNAi不能有效地靶向神经元，我们还为低脂肪储存和高脂肪储存突变配置了经典的遗传屏幕。在我们目前收集的80个突变体中，有些在所有测试条件下储存的脂肪水平都非常高，而另一些突变在饥饿或药物治疗导致的脂肪动员方面存在缺陷。有趣的是，许多突变体在通常由饥饿或饱腹感诱导的行为输出中存在缺陷。因此，这些突变体不会“感觉”饥饿。我们建议每年从分子上鉴定这些顶级候选突变体中的5个，以辨别它们的分子身份，并从它们的表达模式中描绘出哪些细胞介导了脂肪的评估和驱动脂肪储存的行为。我们将确定这些基因中的哪些失活通过调节摄食率来影响脂肪水平，哪些影响总体代谢水平。我们将确定脂肪储存的基因活动的细胞焦点，以及是否有任何基因编码调节储存器官中脂肪实际分类的蛋白质。从饥饿和喂饱的动物的基因阵列中，我们还发现了一些由饥饿或喂食诱导的基因。GFP与这些基因的融合产生了一组关于饥饿状态的强有力的记者。我们将把这些报告基因交叉到我们的突变体库中，以评估哪些突变会导致饥饿状态，哪些不会。此外，我们已经在经典的遗传筛选中使用了这些报告基因，用于未能诱导饥饿标记基因的突变。线虫可以接受大规模的遗传和功能基因组筛选，这在小鼠身上是不可行的。我们的蠕虫基因组学突出了数十个人类基因，这些基因是我们已经识别的蠕虫基因的同源物。在某些情况下，这些基因编码的蛋白质对药物开发具有吸引力。因此，线虫脂肪储存途径基因的鉴定为人类肥胖的干预提供了靶点。与公共健康相关我们的线虫基因失活分析揭示了数百个调节脂肪储存的基因，其中许多与人类同源。对线虫肥胖的研究很可能确定干预人类肥胖的目标。

DESCRIPTION (provided by applicant): From a combination of genetic analyses and RNAi screening, we have discovered hundreds of gene inactivations and mutations that promise to reveal the neuroendocrine circuit through which C. elegans fat storage set points are determined. Because RNAi does not as potently target neurons, we have also configured classical genetic screens for low fat storage and high fat storage mutations. Some of the 80 mutants in our current collection store extraordinarily high levels of fat under all conditions tested whereas others have defects in the mobilization of fat induced by starvation or drug treatments. Interestingly, many of the mutants have defects in the behavioral outputs normally induced by starvation or satiety. Thus these mutants do not "feel" starved. We propose to molecular identify 5 of these top candidate mutants per year to discern their molecular identity as well as to delineate from their expression pattern which cells mediate the assessment of fat and the behaviors that drive fat storage. We will determine which of these gene inactivations affect fat levels by regulating rates of feeding and which affect gross metabolic levels. We will determine the cellular focus of gene activity for fat storage and whether any of the genes encode proteins that mediate the actual sorting of fats in the storage organs. From a gene array of starved and well fed animals, we have also discovered a number of genes that are induced by starvation or by feeding. GFP fusions to these genes have generated a robust set of reporters of the starved state. We will cross these reporter genes into our mutant collection to assess which mutants induce a starved state and which do not. In addition, we have used these reporter genes already in a classical genetic screen for mutants that fail to induce a starvation marker gene. C. elegans is amenable to large scale genetic and functional genomic screens which is not feasible in mice. Our worm genomics highlights scores of human genes which are homologues of the worm genes we have identified. In some cases, the genes encode proteins that are attractive for the development of drugs. Therefore, identification of fat storage pathway genes in C. elegans provides targets for intervention of human obesity. PUBLIC HEALTH RELEVANCE Our C. elegans gene inactivation analysis has revealed hundreds of genes that regulate of fat storage, many of which have human homologues. The studies of obesity in C. elegans is likely to identify targets for intervention of obesity in human.