Roles of protein degradation in the circadian clock

项目总结/摘要 生物钟几乎影响哺乳动物生活的各个方面，调整我们的内部 生理过程的最佳时间。了解分子电路 昼夜节律时间提供了对生物钟如何驱动明显节奏的洞察，以及当生物钟处于静止状态时应该修复什么。 昼夜节律系统中断（即轮班工作期间）。昼夜节律时间编码在节奏 在负反馈回路系统中调节“时钟基因”的表达。这个时机至关重要 生物钟系统是节律丰富的时钟蛋白的昼夜降解，然而， 机制仍然难以捉摸。我们已经开始阐明这些机制， 开发一种新的功能筛选方法，旨在确定哪些E3泛素 连接酶降解哪些时钟蛋白。三个发条目标的屏幕数据表明了这一点 方法是敏感和具体的，因此正如我们所希望的那样运作。当前的一个主要目标 应用程序是继续筛选，并验证，E3连接酶的其他发条蛋白， 以及一些关键的节律性昼夜节律输出。我们相信鉴定这些E3连接酶及其 生物钟功能中的作用将揭示生物钟治疗干预的新的潜在目标， 相关疾病。 我们恢复的第一个屏幕命中，Siah 2，已经揭示了显着和意想不到的 对生物钟功能和生物钟如何调节新陈代谢有了新的认识。我们发现 缺乏功能性Siah 2基因的雌性小鼠失去了一种“保护”饮食的机制， 诱发性肥胖这似乎是由于女性在核心生物钟中的特殊作用。 这些结果表明，第一次，女性特有的时钟机制存在， 它们直接影响了女性特有的生物学。不幸的是，绝大多数 昼夜节律数据来自雄性小鼠。因此，我们现在计划重新评估时钟功能， 女性的昼夜节律调节，以进一步识别和定义性别特异性时钟机制 机制提供了一个背景，研究Siah 2在女性时钟的作用。 随着该领域的发展，了解生物钟功能的性别差异将至关重要 基于昼夜节律的疗法 !

Project Summary/Abstract Circadian clocks influence nearly all aspects of mammalian life, aligning our internal physiological process to optimal times of day. Understanding the molecular circuitry keeping circadian time provides insight into how the clock drives overt rhythms, and what to fix when the circadian system is disrupted (i.e. during shift work). Circadian time coded in the rhythmic regulation of “clock gene” expression in a negative feedback loop system. Critical to this timing system is the circadian degradation of rhythmically abundant clock proteins, however these mechanisms have remained elusive. We have begun elucidating these mechanisms by developing a novel functional screening approach designed to identify which E3 ubiquitin ligases degrade which clock proteins. Screen data on three clockwork targets indicate this approach is sensitive and specific, thus operating as we hoped. A major goal of the current application is to continue to screen for, and validate, E3 ligases for other clockwork proteins as well as some key rhythmic circadian outputs. We believe identifying these E3 ligases and their roles in clock function will reveals new potential targets for therapeutic intervention of clock- related disorders. The first screen hit we have recovered, Siah2, has revealed remarkable and unexpected new insights into both clock function and how the clock regulates metabolism. We found that female mice lacking a functional Siah2 gene lost a mechanism that “protects” against diet- induced obesity. This appears to be due to a female-specific role in the core circadian clock. These results suggest, for the first time, that female-specific clockwork mechanisms exist, and that they contribute directly to female-specific biology. Unfortunately, the vast majority of circadian data are from male mice. Therefore, we now plan to reassess clock function and circadian rhythm regulation in females to further identify and define the sex-specific clockwork mechanisms to provide a background for examining the role of Siah2 in female clocks. Understanding sex-differences in circadian clock functions will be critical as the field develops circadian-based therapeutics. !