The Role of ATM and ATR in Arabidopsis Telomere Biology

端粒是一种重要而复杂的核蛋白结构，它在真核生物线性染色体的物理末端形成保护帽，防止染色体末端被DNA修复机制加工成双链断裂。矛盾的是，参与双链断裂修复的蛋白质在物理上与染色体末端相关，对端粒维持和末端保护至关重要。这项工作的总体目标是更清楚地定义模式植物拟南芥中DNA损伤反应与端粒完整性之间的关系。具体来说，本研究旨在阐明DNA损伤反应的两个主要调节因子，细胞周期依赖性蛋白激酶ATM和ATR，在染色体末端的维持、保护和感知中的作用。Shippen实验室先前的研究表明，ATM和ATR在拟南芥端粒DNA和染色体完整性的维持中起着关键作用。这些研究将利用这种多细胞真核生物的遗传易感性及其对端粒功能障碍的显著耐受性。对于目的1，ATM和ATR与已知的端粒相关蛋白和染色体末端在体内的相互作用将被检查。对于目标2，将研究ATR在端粒维持中的作用机制，以确定ATR如何促进端粒结构，以及端粒维持是否需要其催化ATR。目的3将研究拟南芥对端粒功能障碍的反应，并研究ATM是否在检查点能力中起作用。此外，研究人员还提出了一些实验来验证一种假设，即端粒酶缺陷突变体的延长存活是由一种阻止端粒功能失调细胞增殖的基因组监视机制促进的。这项工作将阐明在植物发育的背景下对端粒功能障碍导致的严重基因组胁迫的分子反应。这些研究将在细胞水平上揭示植物生存的潜在机制，并揭示端粒与促进染色体完整性的因素之间的新联系。鉴于这项工作的基本性质，这些发现可能与非常广泛的真核生物有关。多年来，Shippen实验室培养了大量的学生，使他们在基因组研究的前沿工作的同时，获得了植物分子生物学，细胞遗传学和生物化学方面的宝贵专业知识。Shippen博士还为高中学生和教师以及本科生和研究生组织举办了许多讲座。PI对实验室管理也有长期的兴趣，并曾担任实验室管理课程的讲师。此外，她以指导女科学家而闻名。

Telomeres are essential and complex nucleoprotein structures that form protective caps on the physical ends of linear eukaryotic chromosomes and prevent the terminus from being processed by the DNA repair machinery as a double-strand break. Paradoxically, proteins involved in double-strand break repair physically associate with the chromosome terminus and are essential for telomere maintenance and end protection. The overall goal of this work is to more clearly define the relationship between the DNA damage response and telomere integrity in the model plant, Arabidopsis thaliana. Specifically, this study seeks to elucidate the roles of two master regulators of the DNA damage response, the cell cycle-dependent protein kinases ATM and ATR, in the maintenance, protection and perception of chromosome ends. Previous work by the Shippen lab demonstrated that ATM and ATR play pivotal roles in the maintenance of telomeric DNA and chromosome integrity in Arabidopsis. These studies will exploit the genetic tractability of this multi-cellular eukaryote and its remarkable tolerance to telomere dysfunction. For Objective 1, ATM and ATR interactions with known telomere-associated proteins and with chromosome ends in vivo will be examined. For Objective 2, the mechanism of ATR action in telomere maintenance will be investigated to determine how ATR contributes to telomere architecture, and whether its catalytic ATR is required for telomere maintenance. Objective 3 will examine the Arabidopsis response to telomere dysfunction and investigate whether ATM acts in a checkpoint capacity. In addition, experiments are proposed to test the hypothesis that the extended survival of telomerase-deficient mutants is facilitated by a genome surveillance mechanism that blocks the proliferation of cells with dysfunctional telomeres.This work will elucidate molecular responses to the severe genome stress that results from telomere dysfunction in the context of plant development. These studies will reveal novel insight into the underlying mechanisms for plant survival at the cellular level, and also uncover new connections between telomeres and the factors that promote chromosome integrity. Given the fundamental nature of this work, the findings are likely to be relevant to a very broad range of eukaryotic organisms. Over the years, the Shippen lab has trained a large number of students, allowing them to gain valuable expertise in plant molecular biology, cytogenetics, and biochemistry, while working at the cutting edge of genome research. Dr. Shippen has also presented numerous lectures for high school students and teachers and undergraduate and graduate student organizations. The PI also has a long-standing interest in laboratory management and has served as an instructor for a laboratory management course. Furthermore, she is well-known for mentoring women scientists.