Molecular and Neural Mechanisms of Sleep Regulation by TARANIS

 描述(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、工作场所生产率和公共安全。睡眠通常发生在一天中的特定时间段，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。尽管控制我们睡眠时间的生物钟的分子和解剖学基础已经被广泛研究，但调节睡眠持续时间的分子和神经回路却没有被很好地理解。识别控制睡眠持续时间的新基因和电路将有助于 阐明了这一神秘的生物过程。果蝇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。利用短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(Tara)。Tara基因的突变导致睡眠时间显著缩短(高达80%)。[[重要的是，Tara突变体表现出红眼(黑麦)水平降低，其表达受稳态睡眠驱动的调节。因此，分离Tara为研究睡眠稳态的分子机制提供了一个令人兴奋的机会，而睡眠稳态是一个关键过程，人们对此知之甚少。以往的研究表明，Tara及其哺乳动物同源基因参与转录调控和细胞周期进程，并含有Cyclin A(Cyclin A，Cyca)结合的同源结构域。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尚不清楚。我们的初步研究表明，Tara通过两条互补的途径促进睡眠：1)上调Cyca的蛋白表达并抑制CDK1(一种结合Cyca和睡眠负调节因子的细胞周期蛋白依赖的激酶)；2)上调Daddle(DAW)的转录，DAW是一种激活素样信号分子和睡眠正调节因子。此外，我们的数据还发现，在与哺乳动物下丘脑类似的外侧部(PL)，~14个CyCA表达细胞是一个新的睡眠中枢。在这些初步数据的基础上，我们建议(目标1)确定Tara如何与其他细胞周期蛋白相互作用来调节睡眠，(目标2)Tara如何与Daw相互作用来调节睡眠，Daw是否起到诱导睡眠的动态平衡信号的作用，以及(目标3)确定Tara在哪里以及何时需要睡眠，以及PL神经元如何连接到其他睡眠中心。拟议中的实验将对睡眠稳态产生重要的机械论见解。]]

 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.]]