DEFECTS IN MITOCHONDRIAL PROTEIN-SYNTHESIS AND RESPIRATORY-CHAIN ACTIVITY SEGREGATE WITH THE TRANSFER RNA(LEU)(UUR) MUTATION ASSOCIATED WITH MITOCHONDRIAL MYOPATHY, ENCEPHALOPATHY, LACTIC-ACIDOSIS, AND STROKE-LIKE EPISODES
DEFECTS IN MITOCHONDRIAL PROTEIN-SYNTHESIS AND RESPIRATORY-CHAIN ACTIVITY SEGREGATE WITH THE TRANSFER RNA(LEU)(UUR) MUTATION ASSOCIATED WITH MITOCHONDRIAL MYOPATHY, ENCEPHALOPATHY, LACTIC-ACIDOSIS, AND STROKE-LIKE EPISODES
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DOI：
10.1128/mcb.12.2.480
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发表时间：
1992-02-01
影响因子：
5.3
通讯作者：
SCHON, EA
中科院分区：
文献类型：
--
作者：
KING, MP;KOGA, Y;SCHON, EA
将来自两名不相关的MELAS（线粒体肌病、脑病、乳酸性酸中毒和中风样发作）患者的细胞质与缺乏内源性线粒体DNA（mtDNA）的人细胞（rho（0）细胞）融合，MELAS患者在线粒体基因组的tRNA（Leu（UUR））基因的核苷酸位置3243处具有A -> G转换。 对含有< 15或大于或等于95%突变基因组的所选胞质杂种系进行遗传、生物化学和形态学特征差异的检查。 含有大于或等于95%突变mtDNA的胞质杂交体，但不含正常mtDNA的胞质杂交体，在大鼠中表现出线粒体翻译产物的合成和稳态水平的降低。 此外，NADH脱氢酶亚基1（ND 1）在聚丙烯酰胺凝胶电泳上的迁移率也略有改变. 该突变还与严重的呼吸链缺乏症有关。 检测到对应于16 S rRNA + tRNA（Leu（UUR））+ ND 1基因的RNA转录物的稳态水平的小但一致的增加。 然而，没有证据表明重链编码的转录本的加工存在重大错误，或者线粒体rRNA或mRNA的稳态水平或比率发生改变。 这些结果为tRNA（Leu（UUR））突变与这种线粒体疾病的发病机制之间的直接关系提供了证据。
Cytoplasts from two unrelated patients with MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes) harboring an A --> G transition at nucleotide position 3243 in the tRNA(Leu(UUR)) gene of the mitochondrial genome were fused with human cells lacking endogenous mitochondrial DNA (mtDNA) (rho(0) cells). Selected cybrid lines, containing < 15 or greater-than-or-equal-to 95% mutated genomes, were examined for differences in genetic, biochemical, and morphological characteristics. Cybrids containing greater-than-or-equal-to 95% mutant mtDNA, but not those containing normal mtDNA, exhibited decreases in the rats of synthesis and in the steady-state levels of the mitochondrial translation products. In addition, NADH dehydrogenase subunit 1 (ND 1) exhibited a slightly altered mobility on polyacrylamide gel electrophoresis. The mutation also correlated with a severe respiratory chain deficiency. A small but consistent increase in the steady-state levels of an RNA transcript corresponding to 16S rRNA + tRNA(Leu(UUR)) + ND 1 genes was detected. However, there was no evidence of major errors in processing of the heavy-strand-encoded transcripts or of altered steady-state levels or ratios of mitochondrial rRNAs or mRNAs. These results provide evidence for a direct relationship between the tRNA(Leu(UUR)) mutation and the pathogenesis of this mitochondrial disease.