MITOCHONDRIAL DEFECTS IN NEURO-OPHTHALMOLOGICAL DISEASE

线粒体脑肌病在临床上，形态学上， 和生化多样性的疾病。 在过去的几年里， 已经发现特定的线粒体DNA（mtDNA）突变导致 几种人类疾病。 不幸的是， 线粒体DNA突变的鉴定， 推测的病因学和这些疾病的发病机制。 这项提案的目的是分析病理后果， 几种特定mtDNA突变的分子遗传学原因， 神经眼科疾病 该分析将利用 独特的细胞培养系统，允许分析mtDNA突变 在一个中立的核背景下。 该系统基于隔离 完全缺乏线粒体DNA的人类细胞系（p-O细胞系）， 能够用外源性线粒体重新填充这些细胞，因此， 线粒体DNA 该系统将应用于MELAS疾病的分析 （线粒体肌病、脑病、乳酸酸中毒和卒中样） episodes）。 线粒体DNA的tRNA-Leu（UUR）中有两个点突变， 已知会导致这种疾病。 通过检测生化指标， 这两种突变的形态和遗传后果，以及 通过比较结果，应该可以确定 发病的分子机制。 同样，NARP （神经源性肌无力、共济失调和色素性视网膜炎）， ATP合成酶的mtDNA编码的亚基6中的点突变，和 将研究其他神经眼科疾病。 后才 具体的缺陷及其原因是已知的，是否可能 为患有这些疾病的患者制定合理的治疗方法。 该体外系统将允许用于代谢的确切代谢要求。 呼吸链功能受损的细胞。 此外，还研究了不同生长条件或处理对 可以检测突变的和野生型的mtDNA。 如果一个基因组可以 在其复制中优先受损或抑制，它可能是 有可能为这些目前无法治愈的疾病设计治疗方法， 致命的疾病 除了这些疾病之外， 建议，这个模型系统也可以应用到其他的研究 已知或怀疑线粒体参与的疾病， 拟议的分析将为这些未来的 特征化。

The mitochondrial encephalomyopathies are a clinically, morphologically, and biochemically diverse group of disorders. In the past several years, specific mitochondrial DNA (mtDNA) mutations have been found to result in several such human diseases. Unfortunately, there has been little or no correlation between the identification of the mtDNA mutations, the presumed etiology, and the pathogenesis of these disorders. The goal of this proposal is to analyze the pathological consequences and the molecular genetic causes of several specific mtDNA mutations causing neuro-ophthalmological disease. This analysis will take advantage of a unique cell culture system that permits the analysis of mtDNA mutations in a neutral nuclear background. This system is based upon the isolation of human cell lines that completely lack mtDNA (p-O cell lines) and the ability to repopulate these cells with exogenous mitochondria, and thus, mtDNA. This system will be applied to the analysis of the disease MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes). Two point mutations, both in tRNA-Leu(UUR) of the mtDNA, are known to result in this disease. By examining the biochemical, morphological and genetic consequences of these two mutations, and comparing the results, it should be possible to determine the precise molecular mechanism of pathogenesis. In a similar fashion, NARP (neurogenic muscle weakness, ataxia and retinitis pigmentosa), caused by a point mutation in the mtDNA-encoded subunit 6 of ATP synthetase, and other neuroophthalmological diseases will be studied. Only after specific defects and their causes are known, will it be possible to develop rational therapies for patients suffering from these diseases. This in vitro system will permit the exact metabolic requirements for cells with impaired respiratory chain function to be determined. In addition, the effects of different growth conditions or treatments on the mutated and wild-type mtDNAs can be examined. If one genome can be preferentially damaged or inhibited in its replication, it may be possible to devise treatments for these currently incurable, and often fatal diseases. In addition to those diseases, being studied in this proposal, this model system can also be applied to the study of other diseases where mitochondrial involvement is known or suspected, and the proposed analyses will provide a foundation for these future characterizations.