Nuclear Gene Involvement in Cytochrome Oxidase Deficiency

核基因参与细胞色素氧化酶缺乏症

• 批准号: 7557059
• 负责人: ERIC A. SCHON
• 金额: $ 23.65万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7557059
• 关键词: cell line; cytochrome oxidase; enzyme biosynthesis; enzyme deficiency; enzyme mechanism; enzyme structure; fibroblasts; gene complementation; genetic disorder; genetic mapping; genetic screening; human tissue; isozymes; molecular pathology; patient oriented research

Cytochrome c oxidase (COX), or complex IV of the mitochondrial respiratory chain, is a copper- and hemecontaining metalloprotein composed of 13 subunits, 3 encoded by mitochondrial DNA (mtDNA) and 10 by nuclear DNA (nDNA). A number of COX-deficiency disorders are associated with point mutations in mtDNAencoded COX subunits, but very little is known regarding the molecular basis of mendelian-inherited COX deficiency disorders, which display widely varying phenotypes, including both generalized and tissuespecific clinical presentations. In particular, no mutation in any of the 10 nDNA-encoded COX subunits has yet been found. In the last four years, however, mutations have been found in four COX assembly genes - COX10 , SC01, SC02, and SURF1. We believe that other such genes exist, and propose to identify them by screening our large collection of fibroblasts from patients with COX deficiency. We propose to first, screen for "obvious" candidate genes among the known COX structural and assembly genes. Among those cell lines which survive this first screen, we will use functional complementation by a combination of rodent-human monochromosomal hybrids and microcell-mediated chromosomal transfer to identify complementation groups and candidate chromosomal loci. The culprit genes at these loci will be identified by a combination of microsatelle and deletion mapping, coupled with a judicious sequencing of candidate genes in the region. Any new gene thus identified will be characterized as to its role in COX structure, function, and tissue-specific expression. Uncovering the molecular basis of COX deficiency will be useful in terms of pointing the way to diagnosis and treatment of these generally fatal and untreatable disorders. Moreover, these errors will be extremely useful in understanding fundamental biological phenomena, such as COX holoenzyme assembly, COX function, mitochondrial importation, and energy utilization and production. There are no naturally occurring COX mutants in higher eukaryotes other than those causing the diseases outlined above. Thus, elucidating the molecular basis of the COX deficiencies will afford us new and useful insights from both a clinical and scientific standpoint.

细胞色素 c 氧化酶 (COX) 或线粒体呼吸链复合体 IV，是一种含铜和血红素的金属蛋白，由 13 个亚基组成，其中 3 个由线粒体 DNA (mtDNA) 编码，10 个由核 DNA (nDNA) 编码。许多 COX 缺陷性疾病与 mtDNA 编码的 COX 亚基的点突变有关，但人们对孟德尔遗传性 COX 缺陷性疾病的分子基础知之甚少，这些疾病表现出广泛不同的表型，包括普遍的和组织特异性的临床表现。特别是，尚未发现 10 个 nDNA 编码的 COX 亚基中的任何一个发生突变。 然而，在过去四年中，四个 COX 组装基因（COX10、SC01、SC02 和 SURF1）中发现了突变。我们相信还存在其他此类基因，并建议通过筛选来自 COX 缺陷患者的大量成纤维细胞来识别它们。我们建议首先在已知的COX结构和组装基因中筛选“明显”的候选基因。 在那些在第一次筛选中存活下来的细胞系中，我们将通过结合啮齿动物-人类单染色体杂交和微细胞介导的染色体转移来使用功能互补来识别互补组和候选染色体位点。 这些位点的罪魁祸首基因将通过以下组合来识别： 微卫星和缺失图谱，加上对该区域候选基因的明智测序。 由此鉴定的任何新基因都将表征其在 COX 结构、功能和组织特异性表达中的作用。 揭示 COX 缺乏症的分子基础将有助于为这些通常致命且无法治疗的疾病的诊断和治疗指明方向。 此外，这些错误对于理解基本的生物现象非常有用，例如 COX 全酶组装、COX 功能、线粒体输入以及能量利用和生产。 除了引起上述疾病的突变体之外，高等真核生物中不存在天然存在的 COX 突变体。 因此，阐明 COX 缺陷的分子基础将为我们从临床和科学的角度提供新的、有用的见解。