Role of nuclear architecture in the spatial and temporal dynamics of heterochromatin repair

核结构在异染色质修复时空动态中的作用

• 批准号: 9145718
• 负责人: Irene E Chiolo
• 金额: $ 32.59万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-17 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9145718
• 关键词: Actins; Address; Affect; Aging; Architecture; Biochemical; Cancer Etiology; Cells; Chromosomes; Complex; Country; DNA Repair; DNA Sequence; DNA biosynthesis; Data; Development; Disease; Double Strand Break Repair; Drosophila genus; Early Diagnosis; Euchromatin; Excision; Exposure to; Failure; Fostering; Genes; Genetic Recombination; Genetic Transcription; Genome; Genome Stability; Genomic Instability; Goals; Health; Hereditary Disease; Heterochromatin; Human; Human Genome; Investments; Ionizing radiation; Knowledge; Link; Longevity; Malignant Neoplasms; Mass Spectrum Analysis; Microfilaments; Modeling; Molecular; Molecular Target; Motor; Movement; Mutation; Myosin ATPase; Normal Cell; Nuclear; Organism; Outcomes Research; Pathway interactions; Phase; Prevention; Process; Proteins; Publishing; RNA Interference; RNA Interference Pathway; Recruitment Activity; Regulation; Risk; Role; Screening for cancer; Sister Chromatid; Site; Small Interfering RNA; Source; System; TREX1 gene; Testing; Therapeutic Intervention; Time; Work; age related; base; cancer therapy; cancer type; driving force; genome-wide; helicase; high risk; homologous recombination; human disease; imaging genetics; improved; insight; novel; novel strategies; prevent; protein complex; recombinase; recombinational repair; repaired; response; tumor progression; tumorigenesis

SUMMARY Advancing our knowledge of pericentromeric heterochromatin repair is a high impact investment for improving human health: heterochromatin is a poorly characterized region that comprises nearly a third of the human genome; double-strand break (DSB) repair failures in this region affect not just specific genes but also genome-wide stability; and failures here are a high risk because of the abundance of repeated sequences that characterizes this domain. In spite of the foundational importance of characterizing these processes, DSB repair mechanisms in heterochromatin are mostly unknown. We recently discovered a specialized pathway that promotes faithful homologous recombination (HR) repair in heterochromatin while preventing massive genome instability. We discovered a critical role of the Smc5/6 complex in this pathway, but how this complex participates in heterochromatin repair is unknown. Deregulation of heterochromatin repair is likely one of the most underestimated and powerful sources of tumorigenesis, and identifying the components involved is essential for understanding cancer etiology and developing more effective strategies for therapeutic intervention. To gain insight into the role of Smc5/6 in heterochromatin repair, we used mass spectroscopy to identify new interactors of this complex, which will be further investigated in this proposal. Our central hypothesis is that repair occurs in three steps: an initial phase when abnormal progression of HR is suppressed inside the heterochromatin domain; a second phase when repair sites relocalize to the nuclear periphery; and a third phase characterized by the removal of the block to HR progression at the nuclear periphery. We will combine a wealth of imaging, genetic and biochemical approaches in Drosophila cells and organisms to identify the molecular targets involved in these steps, and determine their role in the spatial and temporal regulation of heterochromatin repair. Expected positive outcomes of this research include the first systematic identification of the molecular machinery that protects heterochromatin from massive genome rearrangements, enabling successful completion of HR repair. These studies are also expected to illuminate missing links between nuclear architecture and dynamics, repair progression, RNAi silencing pathways, and the stability of repeated DNA sequences. These results will have an important positive impact by identifying crucial safeguard mechanisms used by normal cells to protect the genome from environmental threats. Mutations in these pathways result in genome instability, tumorigenesis, and reduced life span. Thus, we expect that the proposed studies and future research will trigger exciting advancements in the prevention, early detection, and treatment of cancer and other human diseases associated with genome instability and aging- related disorders.

概括 增进我们对着丝粒周围异染色质修复的了解是一项具有高影响力的投资，旨在改善 人类健康：异染色质是一个特征很少的区域，占人类的近三分之一 基因组；该区域的双链断裂（DSB）修复失败不仅影响特定基因，还影响 全基因组稳定性；这里的失败风险很高，因为存在大量的重复序列 描述了这个域的特征。尽管表征这些过程具有根本重要性，DSB 异染色质的修复机制大多是未知的。我们最近发现了一条专门的途径 促进异染色质中忠实的同源重组 (HR) 修复，同时防止大量 基因组不稳定。我们发现了 Smc5/6 复合物在此通路中的关键作用，但是该复合物如何 参与异染色质修复尚不清楚。异染色质修复的失调可能是其中之一 最被低估和最强大的肿瘤发生来源，识别所涉及的成分是 对于了解癌症病因和制定更有效的治疗策略至关重要 干涉。为了深入了解 Smc5/6 在异染色质修复中的作用，我们使用质谱法 确定该复合体的新相互作用者，将在本提案中进一步研究。我们的中央 假设修复分三个步骤进行：初始阶段 HR 异常进展 异染色质域内受到抑制；第二阶段，修复地点重新定位到核 周边;第三阶段的特点是消除核HR进展的阻碍 周边。我们将结合果蝇细胞中丰富的成像、遗传和生化方法， 有机体来识别这些步骤中涉及的分子目标，并确定它们在空间和空间中的作用 异染色质修复的时间调节。这项研究的预期积极成果包括： 系统鉴定保护异染色质免受大规模基因组影响的分子机制 重新安排，使人力资源修复顺利完成。这些研究也有望阐明 核结构和动力学、修复进展、RNAi 沉默途径之间缺失的联系，以及 重复DNA序列的稳定性。这些结果将通过识别产生重要的积极影响 正常细胞用来保护基因组免受环境威胁的重要保护机制。 这些途径的突变会导致基因组不稳定、肿瘤发生和寿命缩短。因此，我们 预计拟议的研究和未来的研究将在预防、早期预防方面引发令人兴奋的进展 检测和治疗癌症和其他与基因组不稳定和衰老相关的人类疾病 相关疾病。