Control of Alcohol Responses by Actin-Regulating Genes

描述(申请人提供)：酒精滥用障碍是一个主要的医疗保健问题，在美国每年影响数百万人。酒精中毒有重要的遗传病因，但很少有已知的基因对疾病的发展有重大贡献。这项建议的目标是研究调控肌动蛋白细胞骨架的基因，以及它们实现这一目的的分子机制，以调控果蝇的酒精诱导行为。这一想法在两个模型生物体中同时出现。首先，之前对对酒精行为反应发生改变的果蝇突变体进行的基因筛查发现，调节肌动蛋白细胞骨架的多个基因发生了突变。其次，带有肌动蛋白调控蛋白基因敲除的小鼠对酒精的反应也发生了变化，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确定两个小的GTP酶途径，Arf6和Rho家族在调节酒精诱导的行为中的作用。首先，我们将研究Rho-GTP酶调节蛋白的两种不同亚型RhoGAP18B如何不同地参与乙醇诱导的过度活动和镇静的调节。其次，我们将测试Arf6信号通路成员对酒精的反应的突变。ARF6调节膜运输和质膜上肌动蛋白的动态。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在酒精诱导行为中的作用，特别是cofilin的作用，cofilin是一种肌动蛋白切断蛋白，控制着游离球状和丝状肌动蛋白之间的平衡。这些小的GTP酶信号通路的成员从果蝇到哺乳动物都高度保守，其中一些已知参与了脊椎动物和无脊椎动物的学习和记忆等复杂行为。我们预测，这些通路在调节乙醇诱导的行为时也是功能保守的。酗酒是一种毁灭性的疾病，严重影响个人和公共健康。这项拟议的研究将促进我们对酒精中毒发生的遗传基础的理解。这反过来将导致确定新的危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.