Chemical and Molecular Mechanisms of Mitochondrial DNA Degradation

项目总结/摘要 线粒体是亚细胞区室，其对于能量产生、细胞信号传导和细胞增殖至关重要。 在高等真核细胞中蛋白质辅因子的生物合成。线粒体DNA（mtDNA）基因组是 线粒体功能不可或缺，因为它编码氧化磷酸化的蛋白亚基 系统和全套转移和核糖体RNA。线粒体DNA降解是一种重要的机制， 线粒体基因组维护和质量控制措施，以科普线粒体DNA损伤 来源于内源性和环境化学物质。线粒体DNA降解机制及影响因素 人们对所涉问题知之甚少，这是一个重大的知识差距。这种知识是基本的 理解线粒体基因组的维护和病理，因为线粒体DNA降解可能 有助于线粒体DNA耗竭综合征的病因学和先天免疫系统的激活， 循环线粒体DNA这个项目的目的是确定受损mtDNA的化学和分子基础 降解，并阐明一个主要的转录因子和DNA包装蛋白TFAM（线粒体 转录因子A）在DNA降解和修复中的作用。解决这一关键的知识差距将有助于 PI的长期目标是解开线粒体DNA周转的基础及其在线粒体中的作用， 病理生物学该项目的重点是一个普遍存在的DNA损伤和中央DNA修复中间体，即脱碱基 (AP)网站.中心假设是TFAM调节AP病变的稳定性并介导AP-DNA 降解这一假设是基于强有力的初步数据和经验证据。初步 结果将通过使用定量生物化学、计算和细胞生物化学的组合来进一步评估。 接近。具体来说，这项研究计划将描绘TFAM介导的化学和动力学基础， AP-DNA不稳定，描述TFAM参与人细胞中AP-DNA降解，并阐明 TFAM在mtDNA修复中的调节作用。预期的结果是，该项目将填补一个关键的知识 线粒体DNA降解的化学和分子机制以及新的蛋白质因子方面的空白 参与了这个过程。这项申请建立在PI在DNA和蛋白质生物化学方面的强大背景之上， 机械酶学和定量分析，并加速了令人兴奋的研究领域的进展 线粒体生物学。这个项目的意义在于它将确定化学和分子基础 的mtDNA降解途径和TFAM在mtDNA降解和修复的作用。考虑到AP 位点是线粒体DNA修复的关键中间体，对AP-DNA降解的深入了解将对线粒体DNA修复产生广泛的影响。 理解线粒体基因组的维持和不稳定性。这项研究的新知识将 深入推进线粒体DNA维持领域，并可能为开发新的治疗方法提供信息 用于线粒体疾病。

PROJECT SUMMARY/ABSTRACT Mitochondria are subcellular compartments that are critical for energy production, cell signaling, and the biosynthesis of protein cofactors in higher eukaryotic cells. The mitochondrial DNA (mtDNA) genome is indispensable for mitochondrial function because it encodes protein subunits of the oxidative phosphorylation system and a full set of transfer and ribosomal RNAs. mtDNA degradation is an essential mechanism in mitochondrial genomic maintenance and a quality control measure to cope with mitochondrial DNA damage sourced from endogenous and environmental chemicals. The mechanism of mtDNA degradation and factors involved are poorly understood, which represents a significant knowledge gap. Such knowledge is fundamental to the understanding of mitochondrial genomic maintenance and pathology, because mtDNA degradation may contribute to the etiology of mtDNA depletion syndromes and to the activation of the innate immune system by circulating mtDNA. The objective of this project is to define the chemical and molecular basis of damaged mtDNA degradation and to clarify the role of a major transcription factor and DNA packaging protein TFAM (mitochondrial transcription factor A) in DNA degradation and repair. Addressing this critical knowledge gap will facilitate the PI’s long-term goal of unraveling the basis of mitochondrial DNA turnover and its role in mitochondrial pathobiology. This project focuses on a ubiquitous DNA lesion and central DNA repair intermediate, i.e. abasic (AP) sites. The central hypothesis is that TFAM modulates the stability of AP lesions and mediates AP-DNA degradation. This hypothesis is grounded in both strong preliminary data and empirical evidence. Preliminary results will be further evaluated by using a combination of quantitative biochemical, computational, and cellular approaches. Specifically, this research program will delineate the chemical and kinetic basis of TFAM-mediated AP-DNA destabilization, describe the involvement of TFAM in AP-DNA degradation in human cells, and clarify the regulatory role of TFAM in mtDNA repair. The expected outcome is that the project will fill a critical knowledge gap concerning the chemical and molecular mechanisms of mtDNA degradation and novel protein factors involved in the process. This application builds on the PI’s strong background in DNA and protein biochemistry, mechanistic enzymology, and quantitative analysis, and accelerates the progress in an exciting area of research into mitochondrial biology. The significance of this project is that it will define the chemical and molecular basis of an mtDNA-degradation pathway and the role of TFAM in mtDNA degradation and repair. Considering that AP sites are key intermediates in mtDNA repair, insights into AP-DNA degradation will have broad implications for understanding mitochondrial genomic maintenance and instability. New knowledge from this research will profoundly advance the field of mtDNA maintenance and potentially inform the development novel therapeutics for mitochondrial diseases.