Regulation of genome stability by SITR6

描述（由申请人提供）：该项目的长期目标是确定调节哺乳动物沉默调节蛋白SIRT 6活性的分子机制，特别是在基因组稳定性的背景下。此外，本提案中概述的研究将描述 这些监管控制措施与衰老和年龄相关疾病的发病的相关性。SIRT 6已经成为与衰老相关的多种途径的关键调节剂，包括DNA修复，端粒维持，肿瘤发生，炎症和糖酵解。此外，已经证明SIRT 6过表达延长了小鼠的寿命。 尽管有压倒性的证据表明SIRT 6在与衰老相关的多种途径中起作用，但人们对控制SIRT 6活性并使其能够调节如此多样化的细胞过程的上游调节机制知之甚少。在本申请中，我们建议确定控制SIRT 6活性的调节途径;特别是，我们将重点了解在基因组稳定性背景下调节SIRT 6活性的机制。 我们实验室最近的研究表明，SIRT 6是DNA双链断裂（DSB）修复的上游调节因子。我们发现SIRT 6在氧化应激下刺激DSB修复的两个途径。我们未发表的初步数据表明，SIRT 6被JNK 1/2磷酸化，以响应氨基酸S10上的氧化应激，并且这种磷酸化是刺激DSB修复所必需的。我们还表明，除了控制DSB修复，SIRT 6通过抑制转座因子来维持基因组稳定性，并且氧化应激导致SIRT 6从转座因子的启动子重新定位到新形成的DNA断裂位点。因此，我们理想地定位于在基因组稳定性的背景下进行SIRT 6调节的进一步机制研究。因此，我们将追求以下具体目标：（1）鉴定调节SIRT 6刺激DNA修复以响应氧化应激的能力的机制;（2）鉴定调节SIRT 6抑制LINE-1逆转录转座子表达的能力的机制;和（3）通过构建SIRT 6磷酸化位点突变的小鼠模型来确定SIRT 6磷酸化在基因组稳定性和寿命中的作用。 这项研究将为SIRT 6活性的调控机制提供新的重要见解，并描绘出SIRT 6调控的与基因组稳定性和衰老相关的新途径。因此，我们期望这些实验将揭示有关衰老过程的关键新信息，并将有助于开发治疗与年龄相关疾病的新策略，特别是基因组不稳定性疾病，如癌症。

DESCRIPTION (provided by applicant): The long-term goal of this project is to define the molecular mechanisms which regulate the activity of the mammalian sirtuin, SIRT6, especially in the context of genome stability. Additionally, the studies outlined in this proposal will delineate the relevance of these regulatory controls in regards to aging and the onset of age- related disease. SIRT6 has emerged as a critical regulator of multiple pathways related to aging, including DNA repair, telomere maintenance, tumorigenesis, inflammation and glycolysis. Moreover, it has been demonstrated that SIRT6 overexpression extends the lifespan of mice. Despite the overwhelming evidence that SIRT6 operates at the crux of multiple pathways related to aging, very little is known about the upstream regulatory mechanisms which control the activity of SIRT6 and allow it to regulate such a diverse array of cellular processes. In this application we propose to identify the regulatory pathways that control the activity of SIRT6; in particular, we will focus on understanding the mechanisms that regulate the activity of SIRT6 in the context of genome stability. Recent studies by our laboratory demonstrated that SIRT6 is an upstream regulator of DNA double strand break (DSB) repair. We showed that SIRT6 stimulates both pathways of DSB repair under oxidative stress. Our unpublished preliminary data shows that SIRT6 is phosphorylated by JNK1/2 in response to oxidative stress on amino acid S10 and that this phosphorylation is required for the stimulation of DSB repair. We have also shown that, in addition to controlling DSB repair, SIRT6 maintains genome stability by repressing transposable elements, and that oxidative stress causes re-localization of SIRT6 from the promoters of transposable elements to the sites of newly formed DNA breaks. Thus, we are ideally positioned to conduct further mechanistic studies of SIRT6 regulation in the context of genome stability. As such, we will pursue the following specific aims: (1) identify the mechanisms which regulate the ability of SIRT6 to stimulate DNA repair in response to oxidative stress; (2) identify the mechanisms which regulate the ability of SIRT6 to suppress expression of LINE-1 retrotransposons; and (3) determine the role of SIRT6 phosphorylation in genome stability and longevity by constructing mouse models with mutations in the SIRT6 phosphorylation sites. The proposed research will provide novel and important insights into the regulatory mechanisms, which govern SIRT6 activity as well as delineate new pathways regulated by SIRT6 which are relevant to genome stability and aging. As such, we expect that these experiments will reveal critical, new information about the aging process, and will help to develop novel strategies for treating age-related diseases, in particular diseases of genome instability such as cancer.