Control of Alcohol Responses by Actin-Regulating Genes

描述（由申请人提供）：酒精滥用障碍是美国每年影响数百万人的主要卫生保健问题。酒精中毒有重要的遗传病因，但很少有基因是已知的显著促进疾病的发展。本研究的目的是研究调节肌动蛋白细胞骨架的基因及其调控乙醇诱导果蝇行为的分子机制。这个想法同时出现在两种模式生物中。首先，先前对对酒精行为反应改变的果蝇突变体的基因筛选发现，调节肌动蛋白细胞骨架的多个基因发生了突变。其次，敲除肌动蛋白调节蛋白的小鼠也表现出对酒精的反应改变，包括自愿饮酒增加。因此，我们假设肌动蛋白细胞骨架的动态调节是对乙醇行为反应的主要决定因素。我们提出了遗传、分子、生化和细胞培养的方法来定义两个小的GTPase途径，Arf6和rho家族的GTPase在调节酒精诱导行为中的作用。首先，我们将研究Rho-GTPases的调节蛋白RhoGAP18B的两种不同亚型如何不同地参与乙醇诱导的多动和镇静的调节。其次，我们将测试Arf6信号通路成员的突变对酒精的反应。Arf6调节细胞膜交通和肌动蛋白动力学。我们将使用遗传和生化方法来定义Rho和Arf6信号通路之间的分子联系。第三，我们将测试其他肌动蛋白调控基因对乙醇诱导行为的贡献，特别是cofilin的作用，cofilin是一种肌动蛋白切断蛋白，控制游离球形和丝状肌动蛋白之间的平衡。从果蝇到哺乳动物，这些小GTPase信号通路的成员都是高度保守的，其中一些已知参与脊椎动物和无脊椎动物的复杂行为，如学习和记忆。我们预测，这些途径在调节乙醇诱导行为方面也具有功能保守性。酗酒是一种严重影响个人和公众健康的毁灭性疾病。拟议的研究将促进我们对酒精中毒发展的遗传基础的理解。反过来，这将导致确定新的风险因素和治疗酒精滥用障碍的潜在治疗目标。

DESCRIPTION (provided by applicant): Alcohol abuse disorders are a major health care concern that affect millions of people every year in the United States. Alcoholism has a significant genetic etiology, but few genes are known that significantly contribute to the development of the disease. The goal of this proposal is to study genes regulating the actin cytoskeleton, and the molecular mechanisms by which they do so, to regulate ethanol-induced behaviors in Drosophila. This idea emerged in parallel in two model organisms. First, previous genetic screens for Drosophila mutants with altered behavioral responses to alcohol identified mutations in multiple genes regulating the actin cytoskeleton. Second, mice with a knock-out of an actin regulatory protein also showed altered responses to alcohol, including increased voluntary drinking. We therefore postulate that the dynamic regulation of the actin cytoskeleton is a major determinant of behavioral responses to ethanol. We propose genetic, molecular, biochemical, and cell culture approaches to define the roles of two small GTPase pathways, the Arf6, and Rho-family of GTPases in regulating alcohol-induced behaviors. First, we will study how two distinct isoforms of a regulatory protein of Rho-GTPases, RhoGAP18B, are differentially involved in the regulation of both ethanol-induced hyperactivity, and sedation. Second, we will test mutations in members of the Arf6 signaling pathway for their responses to alcohol. Arf6 regulates membrane traffic and actin dynamics at the plasma membrane. We will use genetic, and biochemical approaches to define what the molecular links are between the Rho and Arf6 signaling pathways. Third, we will test the contribution of other actin regulatory genes to ethanol-induced behaviors, notably the role of cofilin, an actin-severing protein that controls the balance between free globular and filamentous actin protein. The members of these small GTPase signaling pathways are highly conserved from Drosophila to mammals, and some are known to participate in complex behaviors such as learning and memory, in vertebrates and invertebrates. We predict that these pathways are also functionally conserved in their regulation of ethanol-induced behaviors. Alcoholism is a devastating disease that severely impacts personal, and public health. The proposed research will advance our understanding of the genetic basis for the development of alcoholism. This in turn, will result in the identification of new risk factors and potential therapeutic targets for the treatment of alcohol abuse disorders. PUBLIC HEALTH RELEVANCE: Alcoholism is a devastating disorder that significantly contributes to mortality, disability, and to healthcare costs. The goal of this research is to understand the genes that determine, and mediate the behavioral responses to alcohol. In conducting this research, we hope to identify risk factors for the development of alcoholism, as well as provide leads for the development of new therapeutic strategies aiding in the treatment of alcohol use disorders.