Molecular and Neural Mechanisms of Sleep Regulation by TARANIS

 描述（由申请人提供）：睡眠具有基本的生物学功能，从苍蝇到人类都是如此。睡眠障碍是一种常见的健康问题，影响生活质量，工作效率和公共安全。睡眠通常发生在一天中的特定时段，并持续一定的时间。睡眠的这两个特征由不同的分子机制控制。尽管控制我们睡眠的生物钟的分子和解剖学基础已经得到了广泛的研究，但调节睡眠持续时间的睡眠稳态的分子和神经回路还没有得到很好的理解。识别控制睡眠时间的新基因和电路将有助于 这一神秘的生物学过程。果蝇的睡眠模型非常适合通过无偏见的遗传筛选发现新的睡眠调节基因。通过对短睡眠突变体的正向遗传筛选，我们分离出了一个新的睡眠基因taranis（塔拉）。塔拉基因突变导致睡眠时间显著减少（高达80%）。重要的是，塔拉突变体表现出红眼（RYE）水平的降低，其表达受稳态睡眠驱动的调节。因此，塔拉的分离提供了一个令人兴奋的机会，研究睡眠稳态，一个关键的过程，是知之甚少的分子机制。以前的研究结果表明，塔拉及其哺乳动物同源物参与转录调控和细胞周期进程，并包含一个细胞周期蛋白A（CycA）结合同源结构域。值得注意的是，另一种细胞周期蛋白CycA最近被证明是一种促进睡眠的因子，但CycA在睡眠中的分子功能还不清楚。我们的初步研究表明，塔拉通过两种互补的途径促进睡眠：1）通过上调CycA的蛋白表达并抑制Cdk 1（一种与CycA结合的细胞周期蛋白依赖性激酶和睡眠的负调节因子），以及2）通过上调dawdle（daw）的转录，daw是一种激活素样信号分子和睡眠的正调节因子。此外，我们的数据确定在侧部（PL），这是类似于哺乳动物下丘脑，作为一个新的睡眠中心的~14 CycA表达细胞。基于这些初步的数据，我们建议（目标1）确定塔拉如何与其他细胞周期蛋白相互作用来调节睡眠，（目标2）塔拉如何与daw相互作用来调节睡眠，以及睡眠是否作为睡眠诱导稳态信号，以及（目标3）确定何时何地需要塔拉来睡眠，以及PL神经元如何连接到其他睡眠中心。拟议的实验将产生对睡眠稳态的重要机制见解。

 DESCRIPTION (provided by applicant): Sleep serves essential biological functions, and is conserved from flies to humans. Sleep disturbance is a common health problem that impinges on quality of life, workplace productivity, and public safety. Sleep usually occurs at specific tims of day and lasts for certain amounts of time. These two features of sleep are controlled by distinct molecular mechanisms. Whereas the molecular and anatomical basis of the circadian clock, which controls when we sleep, has been investigated extensively, the molecules and neural circuits underlying sleep homeostasis that regulates sleep duration are not well understood. Identification of novel genes and circuits that control sleep duration would facilitate elucidation of this mysterious biological process. The Drosophila model for sleep is well suited for discovery of new sleep-modulating genes through unbiased genetic screens. Using a forward-genetic screen for short-sleeping mutants, we isolated a novel sleep gene, taranis (tara). Mutations in tara result in a marked (up to 80%) reduction of sleep duration. [[Importantly tara mutants exhibit decreased levels of REDEYE (RYE), whose expression is regulated by homeostatic sleep drive. Thus isolation of TARA provides an exciting opportunity to investigate the molecular mechanisms underlying sleep homeostasis, a critical process that is poorly understood. Previous findings suggest that TARA and its mammalian homologs are involved in transcriptional regulation and cell cycle progression, and contain a Cyclin A (CycA)-binding homology domain. Notably, CycA, another cell cycle protein, was recently shown to be a sleep-promoting factor, but the molecular function of CycA in sleep is not well understood. Our preliminary studies suggest that TARA promotes sleep by two complementary pathways: 1) by upregulating protein expression of CycA and inhibiting Cdk1 (a Cyclin-dependent kinase that binds CycA and negative regulator of sleep), and 2) by upregulating transcription of dawdle (daw), an Activin-like signaling molecule and positive regulator of sleep. Further, our data identify ~14 CycA expressing cells in the pars lateralis (PL), which is analogous to the mammalian hypothalamus, as a novel sleep center. Building on these preliminary data, we propose to (Aim 1) determine how TARA interacts with other cell cycle proteins to regulate sleep, (Aim 2) how TARA interacts with daw to regulate sleep, and whether DAW acts as a sleep-inducing homeostatic signal, and (Aim 3) determine where and when TARA is required for sleep, and how the PL neurons connect to other sleep centers. The proposed experiments will yield significant mechanistic insights into sleep homeostasis.]]