MITOCHONDRIAL DNA REARRANGEMENT IN NEUROMUSCULAR DISEASE

线粒体是细胞中的主要能量来源。它们包含 它们自己的DNA(MtDNA)，其基因编码呼吸道的组成部分 链/氧化磷酸化系统。它们对于正常的生活是必不可少的 体内所有细胞的功能，对 那些高度依赖有氧代谢的组织的功能， 尤其是肌肉男和布莱恩。自1988年以来，线粒体DNA点突变和 线粒体DNA重排(即大规模缺失[增量-mtDNA]和 复制[dup-mtDNA])已与异类组关联 线粒体脑肌病。这种持续的竞争 申请书建议跟进我们目前获得资助的工作 零星的线粒体DNA缺失，并扩大我们的努力，以包括线粒体DNA 复制，这不仅与散发性疾病有关，而且 还有孟德尔遗传性和母性遗传性疾病。 我们建议处理两个相关的问题。首先，我们将研究 线粒体DNA复制与线粒体DNA缺失的关系 线粒体疾病的发病机制。我们将转移线粒体DNA 复制(Dup-mtDNA)到无mtDNA的细胞(人的pomicron细胞)和 创造细胞质杂交(胞质)系，含有不同比例的 DUP-mtDNA。这些细胞将被分析相关的线粒体 为了了解一种功能特性之间的关系 表型和基因分型。我们还将尝试确定DUP-mtDNA是否 在体内与Delta-mtDNA共存，如果dup-mtDNA能引起Delta-mtDNA 线粒体DNA。第二，我们将研究Delta-mtDNA的遗传互补，通过 含有两个不重叠的两个呼吸缺陷胞体的融合 Delta-mtDNA的同质群体，以及从中筛选出的细胞 野生型功能已经恢复，可能是由于 线粒体和两个基因组之间的互补。 我们还建议创建一种Delta-mtDNA疾病的小鼠模型，通过使用 含有很大比例特定物种的小鼠环状克隆 Delta-mtDNA(来源于衰老小鼠，已知积累低 注射到受精鼠胚胎中的增量线粒体DNA水平)。这个 建立“传递线粒体”小鼠模型的提议被认为是探索性的 在自然界中。尽管这一想法充满了潜在的问题，但 潜在的回报是巨大的，我们希望将其作为辅助 我们工作的目的。

Mitochondria are the main sources of energy in the cell. They contain their own DNA (mtDNA), whose genes encode components of athe respiratory chain/oxidative phosphorylation system. They are essential for the normal functioning of all cells in the body, and are absolutely critical for the function of those tissues that are highly dependent on aerobic metabolism, especially muscle and brian. Since 1988, both mtDNA point mutations and mtDNA rearrangements (i.e. large-scale deletions [delta-mtDNAs] and duplications [dup-mtDNAs]) have been associated with a heterogeneous group of mitochondrial encephalomyopathies. This Continuing Competitive Application proposes to follow up on our currently-funded efforts on sporadic mtDNA deletions, and to expand our efforts to include mtDNA duplications, which are associated not only with sporadic disorders, but with mendelian- and maternally-inherited disorders as well. We propose to address two related issues. First, we will study the relationship between mtDNA duplications and mtDNA deletions in the pathogenesis of mitochondrial diseases. We will transfer mtDNA duplications (dup-mtDNAs) to mtDNA-less cells (human pomicron cells) and create cytoplasmic hybrid (cybrid) lines harboring different proportions of dup-mtDNAs. These cells will be analyzed for relevant mitochondrial functional characteristics in order to understand athe relationship between phenotype and genotype. We will also try to determine if dup-mtDNAs coexist with delta-mtDNAs in vivo and if dup-mtDNAs can give rise to delta- mtDNAs. Second, we will study genetic complementation of delta-mtDNAs, by fusing two respiratory-deficient cybrids containing two non-overlapping homoplasmic populations of delta-mtDNAs,a nd selecting for cells in which wild-type function has been restored, due presumably to fusion of mitochondria and to complementation between the two genomes. We also propose to create a mouse model of delta-mtDNA diseases, by using mouse cybrid clones harboring a large proportion of a specific species of delta-mtDNA (derived from aged mice, which are known to accumulate low levels of delta-mtDNAs) for injection into fertilized mouse embryos. The proposal to create a "transmitochondrial" mouse model is deemed exploratory in nature. Although this idea is fraught with potential problems, the potential payoff is great, and we would like to include it as an ancillary aim of our work.