Contribution of the tRNAIle 4317A→G mutation to the phenotypic manifestation of the deafness-associated mitochondrial 12S rRNA 1555A→G mutation
Contribution of the tRNAIle 4317A→G mutation to the phenotypic manifestation of the deafness-associated mitochondrial 12S rRNA 1555A→G mutation
复制标题
tRNA(Ile) 4317A -> G 突变对耳聋相关线粒体 12S rRNA 1555A -> G 突变表型表现的贡献
DOI：
10.1074/jbc.ra117.000530
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发表时间：
2018-03-02
影响因子：
4.8
通讯作者：
Guan, Min-Xin
中科院分区：
文献类型：
--
作者：
Meng, Feilong;He, Zheyun;Guan, Min-Xin
线粒体12S rRNA中的1555A -> G突变与全世界许多人氨基糖苷诱导的非综合征性耳聋有关。线粒体遗传修饰因子可影响m.1555A - >g突变的表型表达。在这里，我们报道了tRNA（Ile）基因中的一个耳聋易感等位基因（m.4317A -> G）调节m.1555A -> G突变的表型表达。引人注目的是，携带m.4317A -> G和m.1555A -> G突变的大型汉族家系比只携带m.1555A -> G突变的家系表现出更高的耳聋外显率。m.4317A - >g突变影响了tRNA t环59位高度保守的腺嘌呤（Ile）。因此，我们假设m.4317A - >g突变改变了tRNA（Ile）的结构和功能。使用来自中国家族成员的淋巴母细胞样细胞系（3株同时携带m.1555A -> G和m.4317A -> G突变，3株只携带m.1555A -> G突变，3株不携带这些突变的对照），我们发现携带m.4317A -> G和m.1555A -> G突变的细胞系比只携带m.1555A -> G突变的细胞系表现出更严重的线粒体功能障碍。我们还发现m.4317A - >g突变扰乱了tRNA（Ile）的构象、稳定性和氨基酰化效率。这些m.4317A -> G突变诱导的tRNA（Ile）结构和功能的改变加剧了与m.1555A -> G突变相关的线粒体翻译缺陷和呼吸表型。此外，携带m.4317A -> G和m.1555A -> G突变的突变细胞系比仅携带m.1555A -> G突变的突变细胞系表现出线粒体ATP水平和膜电位的更大下降，活性氧的产生增加。我们的研究结果为线粒体12S rRNA和tRNA突变之间协同作用引起的母系遗传性耳聋的病理生理学提供了新的见解。
The 1555A -> G mutation in mitochondrial 12S rRNA has been associated with aminoglycoside-induced and non-syndromic deafness in many individuals worldwide. Mitochondrial genetic modifiers are proposed to influence the phenotypic expression of m.1555A -> G mutation. Here, we report that a deafness-susceptibility allele (m.4317A -> G) in the tRNA(Ile) gene modulates the phenotype expression of m.1555A -> G mutation. Strikingly, a large Han Chinese pedigree carrying both m.4317A -> G and m.1555A -> G mutations exhibited much higher penetrance of deafness than those carrying only the m.1555A -> G mutation. The m.4317A -> G mutation affected a highly conserved adenine at position 59 in the T-loop of tRNA(Ile). We therefore hypothesized that the m.4317A -> G mutation alters both structure and function of tRNA(Ile). Using lymphoblastoid cell lines derived from members of Chinese families (three carrying both m.1555A -> G and m.4317A -> G mutations, three harboring only m.1555A -> G mutation, and three controls lacking these mutations), we found that the cell lines bearing both m.4317A -> G and m.1555A -> G mutations exhibited more severe mitochondrial dysfunctions than those carrying only the m.1555A -> G mutation. We also found that the m.4317A -> G mutation perturbed the conformation, stability, and aminoacylation efficiency of tRNA(Ile). These m.4317A -> G mutation-induced alterations in tRNA(Ile) structure and function aggravated the defective mitochondrial translation and respiratory phenotypes associated with the m.1555A -> G mutation. Furthermore, mutant cell lines bearing both m.4317A -> G and m.1555A -> G mutations exhibited greater reductions in the mitochondrial ATP levels and membrane potentials and increasing production of reactive oxygen species than those carrying only the m.1555A -> G mutation. Our findings provide new insights into the pathophysiology of maternally inherited deafness arising from the synergy between mitochondrial 12S rRNA and tRNA mutations.