Role of human CST in preventing telomere loss

人类 CST 在预防端粒丢失中的作用

• 批准号: 9145437
• 负责人: Weihang Chai
• 金额: $ 37.75万
• 依托单位: WASHINGTON STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-30 至 2017-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9145437
• 关键词: Address; Aging; Aging-Related Process; Biochemical; Biological Aging; Cell Aging; Cell Cycle; Cell Proliferation; Cells; Chromatin; Chromatin Structure; Chromatin Structure Alteration; Chromosomes; Complex; DNA; DNA Binding; DNA Damage; DNA biosynthesis; Data; Defect; Development; Disease; Event; Fiber; Foundations; Funding; G2 Phase; Genetic Transcription; Genome; Genome Stability; Health; Heterochromatin; Human; Knowledge; Lead; Length; Link; Longevity; Maintenance; Mass Spectrum Analysis; Mediating; Methods; Molecular Analysis; Mutagens; Mutation; Nucleosomes; Outcome; Pathway interactions; Patients; Phenotype; Phosphorylation; Phosphorylation Site; Phosphotransferases; Positioning Attribute; Post-Translational Protein Processing; Premature aging syndrome; Production; Proteins; Publishing; RNA; Reagent; Research; Role; S Phase; Signal Transduction; Single-Stranded DNA; Site; Somatic Cell; Stress; Telomere Length Maintenance; Telomere Maintenance; Telomere Pathway; Telomere Shortening; Testing; Therapeutic; Untranslated RNA; Work; anti aging; clinically relevant; design; early onset; innovation; insight; mutant; novel; prevent; protein complex; research study; response; telomere; telomere loss

DESCRIPTION (provided by applicant): Telomeres are the physical ends of chromosomes that protect genome stability by preventing chromosomes from being damaged. Normal somatic cells have limited lifespan due to the loss of telomere DNA during cell proliferation. Understanding the mechanisms that protect telomeres from rapid shortening is vital for preventing premature aging. Studies have discovered that excessive telomere shortening can be attributed to defective C-strand fill-in, telomere replication stress, and aberrant telomere chromatin structure. However, the mechanisms underlying these three pathways are poorly understood. Recently, the Ctc1/Stn1/Ten1 (CST) single-stranded DNA binding complex has been identified as a new player in protecting telomeres. Mutations in Ctc1 cause a complex disease known as Coats Plus, and cells derived from Coats Plus patients display short telomeres. We have found that deficiency in components of the CST complex causes catastrophic telomere loss, inducing early cellular senescence and DNA damage response in human somatic cells. Therefore, it is important to understand the functions of CST in preventing telomere loss. Our data suggest that the CST complex is a multifunctional protein that promotes efficient replication of telomeric DNA as well as mediates C-strand fill-in at chromosome ends to counteract excessive telomere shortening. In addition, our data also suggest that the CST complex may be involved in regulating telomeric chromatin structure, which is critical for maintaining telomere length. The objective of this proposal is to determine the roles of the CST complex in preventing excessive telomere loss, so that effective strategies for treating premature aging associated with telomere loss can be developed. Experiments are designed to determine how post-translational modification of CST facilitates telomeric DNA replication and precisely regulates C-strand fill- in (Aims 1 and 2). In addition, we will determine the effect of replication fork stalling on telomere chromatin organization (Aim 3). This will be accomplished by integration of mass spectrometry, fluorescent DNA fiber analysis, and molecular/biochemical methods. Completion of the proposed research is expected to substantially add to our understanding of telomere maintenance. It may lead to new directions in studying telomere maintenance and facilitating the development of anti-aging therapy.

描述（申请人提供）：端粒是染色体的物理末端，通过防止染色体被破坏来保护基因组的稳定性。正常体细胞由于在细胞增殖过程中端粒DNA的丢失，寿命有限。了解保护端粒免受快速缩短的机制对于防止过早衰老至关重要。研究发现，端粒过度缩短可归因于c链填充缺陷、端粒复制应激和端粒染色质结构异常。然而，这三种途径背后的机制却知之甚少。近年来，Ctc1/Stn1/Ten1 （CST）单链DNA结合复合体被发现在保护端粒中起着新的作用。Ctc1的突变导致一种称为Coats Plus的复杂疾病，来自Coats Plus患者的细胞显示出短端粒。我们发现，CST复合物组分的缺乏会导致灾难性的端粒丢失，诱导人类体细胞的早期细胞衰老和DNA损伤反应。因此，了解CST在预防端粒丢失中的作用是很重要的。我们的数据表明，CST复合物是一种多功能蛋白，可促进端粒DNA的有效复制，并介导染色体末端的c链填充，以抵消端粒过度缩短。此外，我们的数据还表明，CST复合物可能参与调节端粒染色质结构，这对于维持端粒长度至关重要。本提案的目的是确定CST复合物在防止端粒过度丢失中的作用，以便开发有效的策略来治疗与端粒丢失相关的过早衰老。实验旨在确定CST的翻译后修饰如何促进端粒DNA复制并精确调节c链填充（目的1和2）。此外，我们将确定复制叉延迟对端粒染色质组织的影响（目的3）。这将通过整合质谱、荧光DNA纤维分析和分子/生化方法来完成。这项研究的完成有望大大增加我们对端粒维持的理解。这可能为研究端粒维持提供新的方向，促进抗衰老治疗的发展。