Mechanisms of somatic mtDNA mutation detection and elimination

体细胞线粒体DNA突变检测和消除机制

• 批准号: 8806928
• 负责人: Leo J Pallanck
• 金额: $ 19.31万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8806928
• 关键词: Aging; Animal Model; Autophagocytosis; Biological Assay; Biological Models; Biological Process; Collaborations; DNA; DNA-Directed DNA Polymerase; Diabetes Mellitus; Disease; Dose; Drosophila genus; Drosophila melanogaster; Elderly; Excision; Frequencies; Genetic; Genetic Models; Knowledge; Lead; Locomotion; Longevity; Lysosomes; Malignant Neoplasms; Mediating; Methods; Mitochondria; Mitochondrial DNA; Molecular; Morphogenesis; Mutate; Mutation; Mutation Detection; PINK1 gene; Parkinson Disease; Pathogenesis; Pathology; Phenotype; Physiological; Play; Process; Protein-Serine-Threonine Kinases; Proteomics; Quality Control; Role; Severity of illness; Surface; System; Testing; Tissues; Toxic effect; Transgenes; Transgenic Organisms; Ubiquitin-Protein Ligase Complexes; Ubiquitination; Ursidae Family; Work; fly; genetic manipulation; human disease; in vivo; insight; locomotor deficit; mitochondrial DNA mutation; mutant; next generation sequencing; novel; overexpression; parkin gene/protein; public health relevance; research study; therapy development; trafficking; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): Mitochondrial DNA (mtDNA) mutations cause a number of severe maternally transmitted diseases, and the accumulation of somatic mtDNA mutations is implicated in aging and common diseases of the elderly. These mtDNA mutations often coexist with normal mtDNA, a condition known as heteroplasmy. The ratio of mutated to wild-type mtDNA plays a crucial role in the pathogenesis of heteroplasmic disorders, but the mechanisms that influence this ratio are largely unknown. The long-term objective of our work is to define the cellular mechanisms that govern the frequency of deleterious mtDNA mutations in heteroplasmic somatic tissues. Recent work on the Parkinson's disease-related factors PINK1 and Parkin has revealed that these factors are components of a mitochondrial quality control system (MQCS) that can detect dysfunctional mitochondria, and, in collaboration with other cellular factors, promote their autophagic degradation. We hypothesize that the MQCS acts to reduce the frequency of deleterious heteroplasmic mtDNA mutations by detecting dysfunctional mitochondria that bear mutant DNA and targeting them for degradation. To test this hypothesis, we propose to use the model organism Drosophila melanogaster to pursue three aims. The first aim will examine the influence of genetic alterations of the MQCS on the phenotypes of a Drosophila strain with an increased mtDNA mutation frequency. The second aim will examine the influence of genetic perturbations of the MQCS on the mtDNA mutation frequency using a novel next-generation sequencing method. Finally, the third aim will use a recently developed in vivo assay of mitochondrial turnover to test whether mtDNA mutations promote mitochondrial turnover, and whether genetic perturbations of the MQCS influence the effects of mtDNA mutations on turnover. Our studies will contribute to an understanding of the molecular mechanisms that influence heteroplasmy, and this knowledge could ultimately lead to the development of treatments for diseases caused by mtDNA mutations.

描述（由申请人提供）：线粒体DNA（mtDNA）突变引起许多严重的母体传播疾病，并且体细胞mtDNA突变的积累与老年人的衰老和常见疾病有关。这些mtDNA突变通常与正常的mtDNA共存，这种情况称为异质。突变与野生型mtDNA的比率在异质疾病的发病机理中起着至关重要的作用，但是影响该比率的机制在很大程度上尚不清楚。我们工作的长期目标是定义控制异质体细胞组织中有害mtDNA突变频率的细胞机制。关于帕金森氏病相关因素PINK1和Parkin的最新工作表明，这些因素是线粒体质量控制系统（MQC）的组成部分，可以检测到功能障碍的线粒体，并且与其他细胞因素合作，可以促进其自噬降解。我们假设MQC通过检测功能障碍的线粒体含有突变体DNA并将其靶向降解来降低有害异质mtDNA突变的频率。为了检验这一假设，我们建议使用模型有机体果蝇Melanogaster追求三个目标。第一个目的将检查MQC的遗传改变对果蝇菌株的表型，并增加mtDNA突变频率。第二个目标将使用一种新型的下一代测序方法来检查MQC的遗传扰动对mtDNA突变频率的影响。最后，第三个目标将使用最近开发的线粒体转换的体内测定法来测试mtDNA突变是否促进了线粒体转换，以及MQCS的遗传扰动是否影响mtDNA突变对移位的影响。我们的研究将有助于理解影响异质的分子机制，并且这些知识最终可能导致MTDNA突变引起的疾病治疗的发展。