Mechanisms of fat regulation by conserved anti-obesity genes

肥胖影响了大多数美国成年人，对人类健康造成了各种和重大的有害影响。 尽管遗传背景在肥胖中起着重要作用，但只有少数人类基因 已确定易患肥胖症的个体。了解控制存储的途径 体脂对确定可能导致这种疾病易感性的基因至关重要。长期目标是 以确定其活性可以被改变以预防或治疗人类肥胖的基因。这样做的目的是 应用于阐明相关的RNA结合蛋白Spen和Nito调节的机制 肥胖症，并确定细胞自主调节肥胖症的其他候选。一只果蝇模型 旨在剖析基因功能在调节身体脂肪水平中的组织特异性，以及 分析行为改变的贡献并直接测量肥胖率的新工具 并入商店。一种使用培养细胞的补充方法将直接将研究结果转化为 苍蝇模型在哺乳动物脂肪储存中的作用。中心假说是自主作用的基因 果蝇脂肪储存组织(脂肪体，FB)对控制体内脂肪水平将起到保守的作用 哺乳动物脂肪储存。这一想法得到了申请人之前成功识别这种基因的支持， 并通过初步数据分析特定的候选基因，如Spen。这个项目的基本原理是 脂肪储存组织中的调节途径必须对生物体的暗示做出反应，以控制储存的脂肪水平，以及 识别作用于这些途径的关键基因可能直接转化为对基因的洞察 人类肥胖的易感性。该模型将通过追求三个具体目标进行测试：(1)测试 斯彭和尼托以相反的方式调节身体脂肪的假说。(2)检验假设 Spen/Nito通过结合特定的RNA改变基因表达来调节能量平衡；以及(3)识别 新的、保守的脂肪储存自主调节器的候选基因。在目标1中，我们将确定 缺乏Spen和/或Nito两种RNA结合缺陷的苍蝇幼虫脂肪改变的机制基础 同一家族中的蛋白质，已知可调节其他途径的转录输出，但以前从未 与控制肥胖症有关。在目标2中，我们测试了Spen和Nito将特定RNA与靶结合的模型 转录调控的特定代谢靶基因。在目标3中，苍蝇基因的小鼠同源基因 直接调节脂肪在FB中的储存(包括Shep、Rala和NFAT)将在培养中进行功能分析 小鼠脂肪细胞以一种自主的方式识别那些也控制哺乳动物脂肪储存的细胞。这 创新的方法组合将发现基因在脂肪调节中的新作用 目前尚不清楚。这一建议的意义在于它有可能阐明一种新的控制途径 通过RNA结合蛋白储存脂肪，并对其他候选肥胖基因进行表征，提供了显著的 洞察这种疾病的多基因性质，并为未来的治疗确定新的靶点。

Obesity affects a majority of American adults, with diverse and significant detrimental effects on human health. Despite a major role for genetic background in obesity, only a small number of the human genes that predispose individuals to obesity have been identified. Understanding the pathways that control storage of body fat will be crucial for pinpointing genes likely to cause susceptibility to this disease. The long-term goal is to identify genes whose activities can be modified to prevent or treat human obesity. The goals of this application are to elucidate the mechanism by which the related RNA-binding proteins Spen and Nito regulate adiposity, and to identify other candidates for cell-autonomous regulation of adiposity. A fruit fly model has been developed to dissect the tissue specificity of gene function in the regulation of body fat levels, as well as new tools to parse out the contributions of behavioral alterations and to directly measure rates of fat incorporation into stores. A complementary approach using cultured cells will directly translate findings in the fly model to functions in mammalian fat storage. The central hypothesis is that genes acting autonomously in the fruit fly fat-storage tissue (the fat body, FB) to control levels of body fat will play conserved roles in mammalian fat storage. This idea is supported by the applicant's previous success in identifying such genes, and by preliminary data analyzing specific candidate genes, like Spen. The rationale for this project is that regulatory pathways in fat storage tissues must respond to organismal cues to control levels of stored fat, and that identifying key genes acting in these pathways may translate directly to insights into genetic predispositions to human obesity. This model will be tested by pursuing three specific aims: (1) Test the hypothesis that Spen and Nito function in an opposing manner to regulate body fat. (2) Test the hypothesis that Spen/Nito regulate energy balance by binding specific RNAs to alter gene expression; and (3) Identify candidate genes for novel, conserved autonomous regulators of fat storage. In Aim 1, we will determine the mechanistic basis of defects leading to altered fat in fly larvae lacking Spen and/or Nito, two RNA-binding proteins in the same family known to modulate transcriptional output of other pathways but never before implicated in the control of adiposity. In Aim 2, we test a model that Spen and Nito bind specific RNAs to target specific metabolic target genes for transcriptional control. In the Aim 3, the mouse orthologs of fly genes that directly regulate fat storage in the FB (including Shep, Rala and NFAT) will be analyzed functionally in cultured mouse adipocytes to identify those that also control mammalian fat storage in an autonomous manner. This innovative combination of approaches will uncover new roles for genes whose functions in fat regulation are currently unknown. The significance of this proposal lies in its potential to elucidate a new pathway controlling fat storage via RNA-binding proteins, and to characterize other candidate obesity genes, providing significant insights into the multigenic nature of this disease, and identifying new targets for future treatments.