The Molecular and Neural Mechanisms of Circadian Clock Function in Sleep

描述（由申请人提供）：睡眠是一个重要的生命过程，几乎发生在每一个充分研究的生物体中。睡眠调节不足已经成为一个普遍的健康问题，可能会导致各种生理和心理健康障碍。然而，我们对睡眠调节的神经、遗传和分子基础知之甚少。人们认为有两个基本过程调节睡眠，一个是控制睡眠时间的昼夜节律成分（过程C），另一个是根据事先清醒状态驱动睡眠的稳态成分（过程S）。在果蝇、黑腹果蝇和小鼠中进行的研究表明，在驱动过程C的生物钟的核心，进化上保守的转录反馈回路。一个关键的昼夜节律转录激活子时钟（Clk）也调节果蝇和小鼠的睡眠量和维持时间，在多种生物中将过程C和过程S遗传地联系起来。这项建议的最终目的是确定昼夜节律网络在睡眠调节中的功能。在第一个具体目标中，我们将通过测试缺乏某些起搏器回路的果蝇来评估昼夜节律起搏器神经元在睡眠持续和巩固中的功能。其次，我们将通过检查一系列昼夜节律突变体的睡眠行为和挽救clk靶点表达来确定昼夜节律转录反馈系统在睡眠调节中的作用。第三，我们建议揭示昼夜节律系统对睡眠调节施加影响的新分子机制。使用候选基因方法，我们将研究clk激活、昼夜节律调节和睡眠调节基因的功能，使用一系列可在果蝇中获得的遗传试剂，包括新获得的RNAi文库。

DESCRIPTION (provided by applicant): Sleep is a vital life process that occurs in virtually every organism sufficiently examined. Inadequate sleep regulation has become a prevalent health issue that potentially contributes to a variety of physiological and mental health disorders. However, very little is known about the neural, genetic, and molecular underpinnings of sleep regulation. Two fundamental processes are thought to regulate sleep, a circadian component (Process C) that governs sleep timing and a homeostatic component (Process S) that drives sleep as a function of prior wakefulness. Studies performed in both the fruit fly, Drosophila melanogaster, and mice have revealed evolutionarily conserved transcriptional feedback loops at the core of circadian clocks driving Process C. A key circadian transcriptional activator Clock (Clk) also regulates sleep amount and maintenance in both flies and mice, genetically linking Processes C and S in diverse organisms. The ultimate objective of this proposal is to determine the function of the circadian network in sleep regulation. In the first specific aim, we will assess the function of circadian pacemaker neurons in sleep duration and consolidation by testing flies lacking certain subsets of the pacemaker circuit. In the second, we will determine the role of the circadian transcriptional feedback system in the regulation of sleep by examining sleep behavior in a series of circadian mutants and through rescue of CLK-target expression. In the third, we propose to uncover novel molecular mechanisms by which the circadian system imposes its influence on sleep regulation. Using a candidate gene approach, we will study the function of CLK-activated, circadian-regulated, and sleep-regulated genes using an array of genetic reagents available in flies, including the newly available RNAi library. Relevance: Defects in sleep regulation have become an emerging threat to public health, performance, and safety. While experiments outlined in this proposal are designed to improve our understanding of the neural, genetic, and molecular basis of the sleep-wake cycle, we expect the findings will help foster strategies to offset the rising health issues caused by inadequate sleep.