Bodnar A G, Cooper J M, Leonard J V, Schapira A H
Department of Clinical Neurosciences, Royal Free Hospital School of Medicine, University of London, UK.
Biochem J. 1995 Feb 1;305 ( Pt 3)(Pt 3):817-22. doi: 10.1042/bj3050817.
We have characterized cultured skin fibroblasts from two siblings affected with a fatal mitochondrial disease caused by a nuclear genetic defect. Mitochondrial respiratory-chain function was severely decreased in these cells. Southern-blot analysis showed that the fibroblasts had reduced levels of mitochondrial DNA (mtDNA). The mtDNA was unstable and was eliminated from the cultured cells over many generations, generating the rho0 genotype. As the mtDNA level decreased, the cells became more dependent upon pyruvate and uridine for growth. Nuclear-encoded subunits of respiratory-chain complexes were synthesized and imported into the mitochondria of the mtDNA-depleted cells, albeit at reduced levels compared with the controls. Mitochondrial protein synthesis directed by the residual mtDNA indicated that the mtDNA was expressed and that the defect specifically involves the replication or maintenance of mtDNA. This is a unique example of a respiratory-deficient human cell line exhibiting defective mtDNA replication.
我们对来自两名患有由核基因缺陷导致的致命线粒体疾病的兄弟姐妹的培养皮肤成纤维细胞进行了特征分析。这些细胞中的线粒体呼吸链功能严重下降。Southern印迹分析表明，成纤维细胞中线粒体DNA（mtDNA）水平降低。mtDNA不稳定，在许多代培养细胞中被消除，产生rho0基因型。随着mtDNA水平下降，细胞在生长方面变得更加依赖丙酮酸和尿苷。呼吸链复合物的核编码亚基被合成并导入mtDNA缺失细胞的线粒体中，尽管与对照相比水平有所降低。由残留mtDNA指导的线粒体蛋白质合成表明mtDNA是有表达的，并且该缺陷具体涉及mtDNA的复制或维持。这是一个表现出mtDNA复制缺陷的呼吸缺陷型人类细胞系的独特例子。
