Telomere structure and function in Arabidopsis

拟南芥端粒结构和功能

• 批准号: 10455761
• 负责人: Dorothy Shippen
• 金额: $ 37.88万
• 依托单位: TEXAS A&M AGRILIFE RESEARCH
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10455761
• 关键词: Angiosperms; Animal Model; Antioxidants; Arabidopsis; Base Excision Repairs; Binding Proteins; Biology; Cell Nucleus; Cell Survival; Cells; Chromosomes; Complement; Cytoplasm; Cytoplasmic Organelle; DNA; DNA Damage; Data; Development; Disease; Eukaryota; Exhibits; Experimental Designs; Gene Duplication; Genetic; Genome; Genome Stability; Human; Lead; Lesion; Link; Male Infertility; Malignant Neoplasms; Mammalian Cell; Mammals; Metabolism; Mitochondria; Modeling; Molecular; Molecular Probes; Monitor; Mouse-ear Cress; Mutation; Oxidative Stress; Oxygen; Pathway interactions; Plants; Post-Translational Protein Processing; Predisposition; Proteins; RNA Splicing; Reactive Oxygen Species; Regulation; Research; Resources; Role; Signal Transduction; Source; Stress; Structure; TERT gene; Telomerase; Telomere Maintenance; Telomere Pathway; Testing; Variant; Work; assault; biological adaptation to stress; experimental study; genome integrity; insight; macromolecule; male fertility; multiple omics; mutant; novel; oxidative damage; paralogous gene; plant growth/development; protein function; repaired; reproductive; reproductive development; response; stem cells; telomere; trafficking

Project Summary: Reactive oxygen species (ROS) are natural byproducts of oxygen metabolism. Environmental assaults can dramatically elevate ROS, overwhelming the defenses of cellular antioxidants, and triggering damage to essential macromolecules particularly DNA. Oxidative damage is linked to numerous disease states, but despite much research, fundamental questions remain on how cells avert the detrimental impacts of ROS. Mounting evidence implicates telomere proteins in functions beyond the chromosome terminus. Both Protection of Telomeres 1 (POT1) and the telomerase catalytic subunit TERT traffic in and out of the nucleus and are implicated in various aspects of the response to oxidative damage in mammalian cells. However, unmasking potential non-telomeric functions is problematic because of their critical roles in telomere maintenance and stability. In this renewal application, the model eukaryote Arabidopsis thaliana is employed to study how telomere-associated proteins (TAPs) respond to and mitigate oxidative stress. Arabidopsis encodes two highly divergent POT1 paralogs, AtPOT1a and AtPOT1b, which exhibit separation-of-function with respect to canonical telomere biology, and hence present a unique opportunity to elucidate the full complement of POT1 functions. The proposal builds on additional preliminary showing that AtPOT1b accumulates in the cytoplasm, and loss of AtPOT1b significantly elevates ROS and activates numerous cellular defenses against oxidative stress. AtTERT carries a mitochondrial localization signal, suggesting that it too may regulate the response to ROS. The central hypothesis of this proposal is that the TAPs, AtPOT1a, AtPOT1b and AtTERT, serve important roles in the cellular defense against oxidative damage. This hypothesis will be examined through two Specific Aims. For Aim 1, the breadth of POT1 functions in promoting genome integrity will be assessed by testing how POT1a and POT1b regulate oxidative damage in telomeric and non-telomeric DNA, and how POT1b cooperates with POT1a and TERT to avert genome destabilization. The role of ATR signaling in reproductive progenitor cells will be examined in pot1b mutants. Finally, the evolutionary origin of stress response functions in POT1 proteins will be explored. In Aim 2, three complementary strategies will probe the molecular mechanism and interaction partners of TAPs in non-telomeric pathways. These include monitoring the subcellular trafficking of TAPs in response to stress, quantitative mass spec to identify protein binding partners and stress-induced post-translational modifications, and a novel suppressor screen to explore the genetic pathway that enables POT1b and TERT to promote plant development. These studies will increase understanding of the cross- talk between TAPs and the stress response, open new horizons for exploring the non-canonical functions of POT1, and provide a roadmap to explore rare splice variants of human POT1 that cannot associate with telomeres, and yet are associated with increased predisposition to cancer.

项目摘要： 活性氧（ROS）是氧代谢的天然副产品。环境攻击可以 急剧提升ROS，压倒了细胞抗氧化剂的防御，并触发了必要的损害 大分子特别是DNA。氧化损伤与许多疾病状态有关，但尽管 研究，关于细胞如何避免ROS的有害影响的基本问题。越来越多的证据 在染色体末端以外的功能中暗示端粒蛋白。两种保护端粒1（POT1） 以及端粒酶催化亚基TERT流量进出核，与各个方面有关 哺乳动物细胞中对氧化损伤的反应。但是，揭示潜在的非质体功能 由于它们在端粒维护和稳定性中的关键作用，因此有问题。在此续订应用程序中 模型真核生物拟南芥用于研究端粒相关蛋白（TAP）如何反应 并减轻氧化应激。拟南芥编码两个高度不同的POT1旁系同源物，ATPOT1A和ATPOT1B， 相对于规范端粒生物学表现出功能分离，因此提出了独特的 阐明POT1功能的完整补充的机会。该提案以其他初步为基础 表明ATPOT1b积聚在细胞质中，而ATPOT1b的丧失显着升高ROS和 激活许多针对氧化应激的细胞防御措施。 Attert带有线粒体定位信号， 表明它也可能调节对ROS的反应。该提议的核心假设是Taps， ATPOT1A，ATPOT1B和ATTERT，在防止氧化损伤的细胞防御中起重要作用。这 假设将通过两个具体目的进行检查。对于AIM 1，POT1的宽度在促进中起作用 基因组完整性将通过测试POT1A和POT1B如何调节端粒和 非telomeric DNA，以及POT1B如何与POT1A合作，并避免基因组不稳定。的作用 在POT1B突变体中将检查生殖祖细胞中的ATR信号传导。最后，进化起源 将探索POT1蛋白中的应力反应功能。在AIM 2中，三种互补策略将调查 在非tep途径中的TAP的分子机制和相互作用伙伴。这些包括监视 响应压力，定量质量规格以鉴定蛋白质结合伙伴的响应龙头的亚细胞运输，并 压力引起的翻译后修饰和一个新型的抑制筛查，以探索遗传途径 使POT1B和TERT能够促进植物开发。这些研究将增加对跨的理解 水龙头与压力反应之间的对话，开放的新视野，用于探索POT1的非规范功能， 并提供路线图来探索无法与端粒相关的人类Pot1的稀有剪接变体，并且 然而，与癌症的易感性增加有关。