Tissue Specific Expression of Cytochrome c Oxidase

摘要线粒体电子传递链的酶复合物是独特的。每个复合体由编码在两个不同基因组中的亚基组成，线粒体基因组和核基因组。细胞色素c氧化酶（COX）是细胞色素c氧化酶链上的最后一个酶复合体，为分析这些重要呼吸基因的协调和组织特异性转录调控提供了理想的模型系统。该项目的长期目标是了解控制线粒体编码的COX亚基的组织特异性表达和哺乳动物基因发育调控的遗传调控机制。我们将(1)通过与CAT或lacZ报告基因的基因融合，确定COX亚基VIII-H基因中骨骼肌特异性增强子元件(2)通过DNAse超敏，绘制出核蛋白与COX 8h基因中组织特异性增强子之间dna -蛋白相互作用的位点。dna酶足迹和电泳迁移转移分析，并通过基因转激活研究确定这些相互作用的功能意义(3)物理定位牛组织特异性COX亚基VIII亚型基因，(4)通过种间杂交回交在小鼠中定位COX VIII亚型基因。这些研究将首次对一类基因的转录调控进行全面分析，这些基因是组织特异性呼吸基因，对收缩肌的呼吸功能至关重要。该研究结果将有助于深入了解参与氧化代谢的重要多亚基酶复合物的组织特异性亚基的遗传调控，并为我们在未来的研究中解决这些亚型的功能提供工具。＊＊＊

Abstract 9405363 The enzyme complexes of the mitochondrial electron transport chain are unique. Each complex is composed of subunits encoded in two different genomes, the mitochondrial and the nuclear genomes. Cytochrome c oxidase (COX), the last enzyme complex in the chain provides an ideal model system in which to analyze both coordinate and tissue-specific transcriptional regulation of these essential respiratory genes. The long-term goal of this project is to understand the genetic regulatory mechanisms controlling both tissue-specific expression and developmental regulation of mammalian genes for the mitochondrial-encoded COX subunits. We will (1) define skeletal muscle-specific enhancer elements in the gene for COX subunit VIII-H by means of gene fusions with either the CAT or lacZ reporter genes (2) map the sites of DNA-protein interactions between nuclear proteins and tissue-specific enhancers in the COX8H gene by DNAse hypersensitivity, DNAse footprinting and electrophoretic mobility shift assays and determine the functional significance of these interactions by gene transactivation studies (3) physically map the bovine genes for the tissue-specific isoforms of COX subunit VIII and (4) nap the COX VIII isoform genes in the mouse by inter-specific hybrid back-crosses. %%% These studies will constitute the first comprehensive analysis of the transcriptional regulation of a class of genes, the tissue- specific respiratory genes, essential for respiratory function in contractile muscle. The results should provide insight into the genetic regulation of tissue-specific subunits of an essential multi-subunit enzyme complex involved in oxidative metabolism and provide tools to enable us to address the function of these isoforms in future studies. ***