Roles of casein kinase le/d and b-Trcp in the mammalian circadian clock

描述(申请人提供)：在从蓝藻到人类的几乎所有生物中都观察到了昼夜节律。这些节律受“生物钟”的控制，“生物钟”是一种基因决定的、内生的计时器，可以根据环境信号进行调整，比如昼夜周期。我们最熟悉的昼夜节律是我们自己的睡眠/清醒节律，但生理的许多方面都存在昼夜节律，包括警觉性、激素产生和药物疗效。最近的研究表明，在大多数组织中表达的基因中有2%-10%表现出强烈的昼夜振荡，这表明生物钟在我们的生理中扮演着重要的角色。哺乳动物的昼夜节律由一个分子振荡器(“生物钟”)调节，该振荡器由一个自我维持的、细胞自主的转录负反馈环构成。Period(PER)基因是哺乳动物昼夜节律所必需的，PER蛋白是昼夜节律负反馈环的限速因子。因此，要推进我们对时钟的理解，最关键的任务之一是揭示PER蛋白是如何调控的。我们建议研究小鼠PER(Mper)蛋白翻译后调控的两个方面：磷酸化和降解。我们将描述两种类型的转基因小鼠的生物钟功能缺陷：一种表达转基因来扰乱可能的mper激酶的功能，另一种表达一种可能针对蛋白酶体降解的mPER2的因子的敲除。由于PER调节是时钟机制的基础，我们的研究结果将加深我们对生物钟生理的方方面面的理解，从睡眠到与时钟故障相关的人类疾病。我们的发现还将为开发治疗方法提供更好的框架，以对抗与时钟故障相关的人类疾病，如躁郁症、慢性睡眠障碍和季节性情感障碍。

DESCRIPTION (provided by applicant): Circadian rhythms have been observed in nearly all organisms from cyanobacteria to humans. These rhythms are under the control of the "circadian clock," a genetically determined, endogenous timekeeper that can adjust to environmental cues like the day/night cycle. The circadian rhythm most familiar to us is our own sleep/wake rhythm, but there is circadian rhythmicity in many aspects of physiology including alertness, hormone production and drug efficacy. Recent studies showed that 2-10% of genes expressed in most tissues exhibit robust circadian oscillations, suggesting that the circadian clock plays important roles in our physiology. The mammalian circadian rhythms are regulated by a molecular oscillator ("circadian clock") constructed from a self-sustaining, cell-autonomous transcriptional negative feedback loop. Period (Per) genes are essential for the mammalian circadian clock and PER proteins are rate-limiting factors for the circadian negative feedback loop. Thus, one of the most crucial tasks to advance our understanding of the clock is to uncover how PER proteins are regulated. We propose to study two aspects of posttranslational regulation of mouse PER (mPER) proteins: phosphorylation and degradation. We will characterize defects of circadian clock function in two types of genetically modified mice: one expressing a transgene to disrupt the function of likely kinases for mPER, and the other a knockout for a factor likely to target mPER2 for proteosomal degradation. Because PER regulation is so fundamental to the clock mechanism, the results of our studies will deepen our understanding of all aspects of circadian physiology, from sleep to human diseases associated with clock malfunction. Our discoveries will also provide a better framework for the development of treatments to combat human disorders associated with clock malfunction such as manic depression, chronic sleep disorder and seasonal affective disorder.