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: 9010835
• 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/9010835
• 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; Genetic Recombination; Genetic Transcription; Genome; Genome Stability; Genomic Instability; Goals; Health; Hereditary Disease; Heterochromatin; Human; Human Genome; Image; 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; 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 促进我们对周围质聚染色质修复的了解是改善的高影响投资 人类健康：异染色质是一个较差的区域，占人类的近三分之一 基因组；该区域的双链断裂（DSB）维修故障不仅会影响特定基因，还会影响 全基因组稳定性；由于重复的序列丰富，这里的失败是一个高风险 表征了这个域。尽管表征这些过程的基本重要性，DSB 异染色质中的修复机制大多未知。我们最近发现了一条专业途径 这促进了忠实的同源重组（HR）修复，同时预防大量 基因组不稳定性。我们在这条途径中发现了SMC5/6复合物的关键作用，但是这种复合物如何 参与异染色质修复是未知的。异染色质修复的放松管制可能是其中之一 肿瘤发生的大多数低估和强大的来源，并确定所涉及的组件是 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 确定该综合体的新交互者，这将在该提案中进一步研究。我们的中心 假设是修复分为三个步骤：HR异常进展的初始阶段 在异染色质结构域内被抑制；第二阶段维修位点迁移到核 周边;和第三阶段的特征是将块去除核的HR进展 周边。我们将在果蝇细胞中结合大量的成像，遗传和生化方法 生物体确定这些步骤中涉及的分子靶标，并确定其在空间和 异染色质修复的时间调节。这项研究的预期积极结果包括第一个 对保护异染色质免受大型基因组的分子机制的系统鉴定 重排，可以成功完成人力资源维修。这些研究也有望照亮 核架构与动态，维修进展，RNAi沉默途径和 重复的DNA序列的稳定性。这些结果将通过确定 普通细胞使用的关键保障机制可保护基因组免受环境威胁。 这些途径中的突变导致基因组不稳定性，肿瘤发生和寿命降低。因此，我们 预计拟议的研究和未来的研究将引发预防的令人兴奋的进步 检测和治疗与基因组不稳定性和衰老相关的癌症和其他人类疾病 相关疾病。