Regulation of genome stability by SITR6

描述(申请人提供)：该项目的长期目标是确定调节哺乳动物sirtuin，SIRT6活性的分子机制，特别是在基因组稳定的背景下。此外，本提案中概述的研究将描述 这些调控措施与衰老和年龄相关疾病的发病之间的相关性。SIRT6已经成为与衰老相关的多个途径的关键调节因子，包括DNA修复、端粒维持、肿瘤发生、炎症和糖酵解。此外，已经证明过表达SIRT6可以延长小鼠的寿命。尽管有压倒性的证据表明SIRT6在与衰老相关的多个途径中发挥作用，但人们对控制SIRT6活性并允许其调节如此多样化的细胞过程的上游调控机制知之甚少。在这项应用中，我们建议识别控制SIRT6活性的调节途径；特别是，我们将重点了解在基因组稳定的背景下调节SIRT6活性的机制。我们实验室最近的研究表明，SIRT6是DNA双链断裂(DSB)修复的上游调节因子。我们发现SIRT6在氧化应激下刺激了DSB修复的两条途径。我们未发表的初步数据表明，SIRT6被JNK1/2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修复外，SIRT6还通过抑制转座元件来维持基因组的稳定性，并且氧化应激导致SIRT6从转座元件的启动子重新定位到新形成的DNA断裂的位置。因此，我们处于理想的位置，在基因组稳定性的背景下进行SIRT6调控的进一步机制研究。因此，我们将追求以下具体目标：(1)确定调控SIRT6在氧化应激反应中刺激DNA修复的能力的机制；(2)确定调控SIRT6抑制LINE-1反转录转座子表达的能力的机制；以及(3)通过构建SIRT6磷酸化位点突变的小鼠模型，确定SIRT6磷酸化在基因组稳定性和寿命中的作用。这项拟议的研究将为调控SIRT6活性的调控机制提供新的和重要的见解，并描绘出与基因组稳定性和衰老相关的SIRT6调控的新途径。因此，我们预计这些实验将揭示关于衰老过程的关键新信息，并将有助于开发治疗与年龄相关的疾病的新策略，特别是癌症等基因组不稳定的疾病。

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 Our unpublished preliminary data shows that SIRT6 is phosphorylated by JNK1/2 in response to oxidative stress on amino acid S10 and that this phosphorylation is required for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.