Succinyl-COA Synthetase Deficiency: A Model to Study Mitochondrial DNA (MTDNA) De

描述（由申请人提供）： 线粒体DNA（mtDNA）缺失型线粒体肌病是一类重要的、新近被认识到的线粒体疾病，其可引起代谢性肌病以及智力和发育障碍。ADP特异性琥珀酰辅酶A合成酶（SCS）的缺乏，TCA循环的一个组成部分，已被确定为线粒体肌病与mtDNA耗竭的原因之一。已分离出编码SCS β亚基的基因Sucla2的基因陷阱突变体克隆。该突变小鼠ES细胞系已用于产生Sucla 2缺陷的转基因小鼠和小鼠胚胎成纤维细胞（MEF）细胞系。突变的MEFs以及突变的胚胎骨骼肌和脑表现出mtDNA缺失。这一建议是基于这样的假设，即SCS是mtDNA维持和稳定所需的mtDNA类核复合物的重要蛋白质组分。将利用SUCLA2缺陷的细胞来研究mtDNA维持所需的SUCLA2的功能和结构组分。遗传学研究，以确定与SCS相互作用的蛋白质，是mtDNA类核复合物的潜在成分也将继续进行。将产生Sucla 2的小鼠突变体以研究SCS缺乏症的病理生理学，作为mtDNA耗竭和肌病的模型。这些研究将为mtDNA生物学的基本机制提供新的见解，并提供一种新的mtDNA耗竭模型，以促进代谢性肌病重要子集的新治疗策略的开发。 公共卫生相关性： 线粒体DNA（mtDNA）总含量的消耗或减少是线粒体疾病的一个子集的特征，并且在乳腺癌中也观察到。线粒体DNA缺失的细胞和动物模型的发展对于理解线粒体DNA缺失的病理机制以及理解线粒体DNA生物学的基本机制是重要的。该项目建立了一个研究mtDNA缺失的模型，并探索mtDNA维持的基本机制，以最终开发新的治疗策略。

DESCRIPTION (provided by applicant): Mitochondrial myopathy with mitochondrial DNA (mtDNA) depletion is an important and newly recognized class of mitochondrial disease that causes metabolic myopathy as well as intellectual and developmental disabilities. Deficiency of ADP-specific succinyl-CoA synthetase (SCS), a component of the TCA cycle, has been identified as one of the causes of mitochondrial myopathy with mtDNA depletion. A gene trap mutant clone of Sucla2, the gene encoding the beta-subunit of SCS, has been isolated. This mutant mouse ES cell line has been used to generate transgenic mice and mouse embryonic fibroblast (MEF) cell lines deficient for Sucla2. Mutant MEFs as well as mutant embryonic skeletal muscle and brain demonstrate mtDNA depletion. This proposal is based on the hypothesis that SCS is an important protein component of the mtDNA nucleoid complex required for mtDNA maintenance and stability. Cells deficient for SUCLA2 will be utilized to investigate the functional and structural components of SUCLA2 required for mtDNA maintenance. Genetic studies to determine proteins that interact with SCS and are potential components of the mtDNA nucleoid complex will also be pursued. Mice mutant for Sucla2 will be generated to study the pathophysiology of SCS deficiency as a model for mtDNA depletion and myopathy. These studies will provide new insights into fundamental mechanisms of mtDNA biology as well as provide a novel model of mtDNA depletion to facilitate the development of new therapeutic strategies for an important subset of metabolic myopathies. PUBLIC HEALTH RELEVANCE: Narrative Depletion or reduction of total content of mitochondrial DNA (mtDNA) is a feature of a subset of mitochondrial diseases and has also been observed in breast cancer. The development of cell and animal models of mtDNA depletion is important for understanding the pathological mechanisms of mtDNA depletion as well as for understanding fundamental mechanisms of mtDNA biology. This project establishes a model to study mtDNA depletion and to explore basic mechanisms of mtDNA maintenance in order to ultimately develop novel therapeutic strategies for diseases with mtDNA depletion.