Dynamics of Mitochondrial Inheritance in C. elegans Primordial Germ Cells

线虫原始生殖细胞线粒体遗传动力学

• 批准号: 10162312
• 负责人: Aaron Zachary Schwartz
• 金额: $ 4.6万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-16 至 2023-09-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10162312
• 关键词: Affect; Back; Biological; Biological Models; Caenorhabditis elegans; Cell Nucleus; Cell Separation; Cell membrane; Cells; Chemicals; Counseling; DNA Repair; DNA copy number; Data; Daughter; Defect; Development; Distal; Embryonic Development; Endoderm Cell; Ensure; Excision; Female; Female infertility; Future; Generations; Genes; Genetic; Genetic Diseases; Genome; Germ Cells; Germ Lines; Goals; Health; Hereditary Disease; Human; Image; Individual; Inheritance Patterns; Inherited; Intestines; Label; Lobe; Mammals; Membrane; Metabolic; Methods; Mitochondria; Mitochondrial DNA; Mitochondrial Diseases; Mitochondrial Inheritance; Modeling; Molecular; Molecular Chaperones; Mutate; Mutation; Nuclear; Organelles; Oxidants; Oxides; Ploidies; Population; Premature aging syndrome; Process; Quality Control; Research; Resolution; Source; Spermatogenesis; Structure of primordial sex cell; Techniques; Testing; Yeasts; base; conditional mutant; fitness; genome editing; genome integrity; heteroplasmy; male; mitochondrial DNA mutation; mitochondrial genome; mutant; next generation; oxidation; receptor; reproductive system disorder; segregation; stem cells; therapy development; tool; transmission process

PROJECT SUMMARY Mitochondria are dynamic double-membraned organelles that contain an independent genome (mtDNA). Each mitochondrial gene is essential; however, mitochondrial DNA has a substantially higher rate of mutation when compared to the nuclear genome. As a result, mtDNA mutation is one of the most common sources of genetic disease in humans. Nonetheless, relatively few mutations have been established in mitochondrial genomes across generations. Genetic evidence suggests that selection against mutant mtDNAs occurs in the female germline, however, the mechanisms by which mtDNA selection occurs remain poorly understood. The goal of the proposed research is to advance our understanding of mitochondrial DNA inheritance by investigating the molecular and cellular mechanisms of mitochondrial inheritance in C. elegans PGCs, which provide an outstanding model for examining mitochondrial inheritance at cellular resolution. During late embryogenesis, C. elegans PGCs undergo a drastic remodeling process, whereby much of their cell mass and content is discarded. PGC remodeling occurs when PGCs form organelle-filled lobe-like protrusions, which are cut off and digested by adjacent endodermal cells. In the process, most PGC mitochondrial mass is lost. We have observed that mitochondria initially localize into PGC lobes, but a subset subsequently migrates back into PGCs prior to lobe removal. These are presumably the mitochondria that are inherited. I hypothesize that PGC lobe formation and removal is a mechanism whereby the number and/or quality of mitochondria/mtDNAs are regulated to ensure that fit mitochondria are passed on to the next generation. I will approach this hypothesis in two ways. First, I will empirically determine which mitochondria are inherited by PGCs and test the hypothesis that mitochondrial fission is required for proper mitochondrial segregation in PGCs using live imaging. (AIM1). Second, I will determine if C. elegans PGC lobe formation/removal regulates mtDNA/mitochondrial quality during inheritance. I will test the two primary hypotheses of mtDNA selection, the mitochondrial bottleneck and purifying selection, by quantifying mtDNA prior to and following lobe removal in wild type and mitochondrial mutant strains respectively. Then I will test the hypothesis that mitochondrial functionality drives mitochondrial selection in PGC lobes using conserved markers of mitochondrial health (AIM2). Mitochondrial mutations have particularly severe effects on embryonic development and male/female infertility resulting from spermatogenesis defects, premature aging, and developmental arrest. I anticipate that my findings will contribute to a deeper understanding of these mechanisms, and thus, will be essential for developing treatments of human mitochondrial disease and reproductive disorders in the future.

项目摘要 线粒体是动态的双膜细胞器，包含独立的基因组（mtDNA）。每个 线粒体基因是必不可少的;然而，线粒体DNA有相当高的突变率时， 与核基因组相比。因此，线粒体DNA突变是最常见的遗传来源之一， 人类的疾病。尽管如此，在线粒体基因组中已经建立了相对较少的突变 跨越几代人。遗传学证据表明，对突变mtDNA的选择发生在女性身上。 然而，在生殖系中，mtDNA选择发生的机制仍然知之甚少。的目标 这项拟议中的研究是为了通过以下方式来增进我们对线粒体DNA遗传的理解： 研究线粒体遗传的分子和细胞机制。秀丽线虫PGCs， 其提供了用于在细胞分辨率下检查线粒体遗传的杰出模型。 在胚胎发育后期，C.秀丽线虫PGCs经历了剧烈的重塑过程， 质量和内容被丢弃。PGC重塑发生在PGC形成充满细胞器的叶状突起时， 其被切断并被邻近的内胚层细胞消化。在这个过程中，大多数PGC线粒体质量是 迷路了我们已经观察到，线粒体最初定位于PGC叶，但一个子集随后迁移 在切除肺叶之前回到PGCs中。这些可能是遗传的线粒体。我假设 PGC叶的形成和去除是一种机制， 调节线粒体/mtDNA以确保合适的线粒体传递给下一代。我会 从两个方面来探讨这个假设。首先，我将凭经验确定哪些线粒体是遗传的， PGCs和测试的假设，线粒体分裂是需要适当的线粒体分离PGCs 使用实时成像。（目标1）。第二，我将确定是否C。PGC叶的形成/去除调节 线粒体DNA/线粒体质量在遗传过程中。我将检验线粒体DNA选择的两个主要假设， 线粒体瓶颈和纯化选择，通过定量mtDNA之前和之后叶切除， 野生型和线粒体突变株。然后我将检验线粒体 使用线粒体健康的保守标志物，功能性驱动PGC叶中的线粒体选择 （AIM 2）。线粒体突变对胚胎发育和雄性/雌性的影响特别严重。 由于精子发生缺陷、过早衰老和发育停滞而导致的不育。我预计 我的发现将有助于更深入地了解这些机制，因此，将是至关重要的， 在未来开发人类线粒体疾病和生殖障碍的治疗方法。