Analysis of clock proteins in their non-circadian roles

描述（由申请人提供）：生物钟是进化保守的行为和生理过程的协调者。人类生物钟的故障会导致严重的疾病，如睡眠障碍和癌症。昼夜计时是由分子反馈回路完成的，其中包括几个时钟基因及其蛋白质。两个基因周期（per）和永恒（tim）的作用已经在时钟反馈回路中得到了很好的确立，这在模式生物果蝇中起作用。这两个基因的产物，蛋白质PER和TIM，转运到细胞核并随后被降解；这两个事件对于时钟的功能都是必不可少的。令人惊讶的是，在卵巢中，这些蛋白质表现不同。它们的水平不循环；相反，它们在任何时候都保持稳定和细胞质。我们有证据表明，卵巢中PER和TIM的非昼夜表达可能在调节卵子生产中起重要作用。我们假设时钟基因可能与控制代谢稳态和营养分配的信号通路的组成部分相互作用。我们建议使用生物化学和遗传工具在两个具体目标中检验这一假设。首先，我们将研究PER和TIM在卵巢中的遗传和生化相互作用，并利用与繁殖力相关的表型检测它们的功能意义。其次，我们将进行蛋白质相互作用筛选，以鉴定可能与细胞质PER和TIM相互作用的新蛋白质。本研究获得的结果将为我们了解时钟蛋白非昼夜节律表达的功能意义提供重要见解。越来越多的证据表明，那些被认为只起生物钟作用的基因还有其他重要的多效性作用。它们在苍蝇和哺乳动物中都以非昼夜节律的方式起作用。因此，了解模式生物中时钟基因的非昼夜节律功能应该为与人类健康相关的类似过程提供有价值的见解。

DESCRIPTION (provided by applicant): Circadian clocks are evolutionary conserved coordinators of behavioral and physiological processes. Malfunctions of circadian clocks in humans lead to serious pathologies such as sleep disorders and cancer. Circadian timekeeping is accomplished by molecular feedback loops that involve several clock genes and their proteins. The role of two genes period (per) and timeless (tim) has been well established in the clock feedback loop, which operates in the model organism Drosophila melanogaster. The products of these two genes, proteins PER and TIM, translocate to cell nuclei and are subsequently degraded; both events are essential for clock function. Surprisingly, in the ovary, these proteins behave differently. Their levels do not cycle; instead, they remain stable and cytoplasmic at all times. We have evidence that non-circadian expression of PER and TIM in the ovary may have important functions in the modulation of egg production. We hypothesize that clock genes may be interacting with components of signaling pathways that govern metabolic homeostasis and nutrient allocation. We propose to use biochemical and genetic tools to test this hypothesis in two specific aims. First, we will study genetic and biochemical interactions of PER and TIM in the ovary and test their functional significance using fecundity related phenotypes. Second, we will perform protein interaction screens to identify novel proteins that may interact with cytoplasmic PER and TIM. Results obtained in this study will give us important insights into the functional significance of non-circadian expression of clock proteins. There is increasing evidence that genes that were thought to act exclusively as clock components have other important pleiotropic roles. They act in a non-circadian manner in both fly and mammals. Therefore, understanding the non-circadian functions of clock genes in a model organism should provide valuable insights into similar processes related to human health.