Role of CDK9 in the Replication Stress Response

描述（由申请人提供）：该候选人是一名放射肿瘤学家，其职业目标是成为一名独立、自筹资金、高产的学术医师科学家，致力于解开癌症生物学的秘密，并弥合其阐明与临床护理改善之间的差距。他的具体研究兴趣是发现控制基因组完整性的基本生物学过程。他在K08奖期间的培训目标是获得必要的基础知识和实践研究技能，以启动一个独立的研究项目来调查复制应激反应。他将获得检查点信号方面的基础知识，以补充他之前在DNA复制和DNA修复方面的培训，并通过遗传和生化方法方面的培训扩展他的技术背景，以补充他之前在分子生物学和细胞生物学方面的培训，该培训计划利用范德比尔特大学医学中心的优秀资源和培养环境进行为期5年的指导培训。复制应激反应（RSR）是DNA损伤反应的一个子集，它识别DNA复制的挑战，并动员细胞活动，导致细胞周期阻滞，DNA修复或凋亡。RSR的突变促进了基因不稳定细胞的存活和增殖，最终导致癌症。因此RSR起着抗癌屏障的作用。该候选人在人类细胞中使用RNA干扰完成了一项新的功能丧失基因筛选，以鉴定14个高可信度的RSR基因，包括新的RSR基因，周期蛋白依赖性激酶9 （CDK9）。他的初步研究表明，CDK9与ATR/ATR相互作用蛋白（ATRIP）以及其他RSR蛋白在一个或多个复合物中相互作用，并定位于含有ATRIP的病灶。此外，他的初步数据表明，CDK9的激酶活性对于从复制停滞中恢复至关重要。基于这些数据，他假设CDK9通过磷酸化关键底物参与atr介导的复制应激反应来维持基因组完整性。为了验证他的假设，他提出了以下具体目标：(1)确定CDK9与ATR相互作用的调控和功能意义。(2)鉴定CDK9的底物。(3)确定CDK9的活性是如何调控的。这些目标将通过遗传和生化方法的结合来完成，以提供对CDK9功能的机制理解。这些目标的完成将为RSR如何维持基因组完整性和预防癌症提供新的见解。此外，该研究对开发创新的癌症诊断和治疗方法具有重要的临床应用价值。

DESCRIPTION (provided by applicant): The candidate is a radiation oncologist with the career objective of becoming an independent, self- funded, and productive academic physician-scientist, dedicated to unlocking the secrets of cancer biology and bridging the gap between its elucidation and improvement in clinical care. His specific research interest is in discovering the basic biological processes that govern genome integrity. His training goals during the mentored K08 award period are to acquire the foundation of knowledge and practical research skills necessary to initiate an independent research program investigating the Replication Stress Response. He will acquire a foundation of knowledge in checkpoint signaling to complement his prior training in DNA replication and DNA repair and expand his technical background with training in genetic and biochemical methodologies to complement his prior training in molecular biology and cell biology under a 5-year mentored training program using the outstanding resources and nurturing environment of Vanderbilt University Medical Center. The Replication Stress Response (RSR) is a subset of the DNA Damage Response that recognizes challenges to DNA replication and mobilizes cellular activities that lead to cell cycle arrest, DNA repair, or apoptosis. Mutations in the RSR promote the survival and proliferation of genetically unstable cells eventually leading to cancer. Thus the RSR acts as a cancer barrier. The candidate has completed a novel loss of function genetic screen using RNA interference in human cells to identify 14 high-confidence RSR genes, including the novel RSR gene, cyclin-dependent kinase 9 (CDK9). His preliminary studies show that CDK9 interacts in a complex or complexes with ATR/ATR interacting protein (ATRIP) as well as with other RSR proteins and localizes to ATRIP-containing foci. Moreover, his preliminary data indicate that the kinase activity of CDK9 is essential for recovery from replication arrest. Based on these data, he hypothesizes that CDK9 maintains genome integrity by participating in an ATR-mediated replication stress response through phosphorylation of key substrates. To test his hypothesis, he proposes the following specific aims: (1) Determine the regulation and functional significance of the interaction of CDK9 with ATR. (2) Identify substrates of CDK9. (3) Determine how the activity of CDK9 is regulated. These aims will be completed by a combination of genetic and biochemical approaches to provide a mechanistic understanding of CDK9 function. Completion of these aims will provide new insights into the how the RSR maintains genome integrity and prevents cancer. Moreover, this research has significant clinical application for developing innovative ways for diagnosing and treating cancer.