Contribution of a mitochondrial tyrosyl-tRNA synthetase mutation to the phenotypic expression of the deafness-associated tRNASer(UCN) 7511A>G mutation
Contribution of a mitochondrial tyrosyl-tRNA synthetase mutation to the phenotypic expression of the deafness-associated tRNASer(UCN) 7511A>G mutation
复制标题
线粒体酪氨酰-tRNA 合成酶突变对耳聋相关 tRNASer(UCN) 7511A>G 突变表型表达的贡献
DOI：
10.1074/jbc.ra119.010598
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发表时间：
2019-12-13
影响因子：
4.8
通讯作者：
Guan, Min-Xin
中科院分区：
文献类型：
--
作者：
Fan, Wenlu;Zheng, Jing;Guan, Min-Xin
核修饰基因已被提出来修饰线粒体DNA突变的表型表达。利用靶向外显子组测序方法，我们发现线粒体酪氨酰-tRNA合成酶2（YARS 2）中的p.191 Gly>瓦尔突变与tRNA（Ser（UCN））7511 A>G突变相互作用导致耳聋。值得注意的是，同时携带YARS 2 p.191 Gly>瓦尔和m.7511 A>G突变的中国家系成员比仅携带m.7511 A>G突变的家系成员表现出更高的耳聋发生率。m.7511A>G突变改变了tRNA（Ser（UCN））的氨酰受体茎处的A4：U69碱基配对为G4：U69配对，并扰乱了tRNA（Ser（UCN））的结构和功能，包括增加的解链温度、改变的构象、不稳定性和突变体tRNA的异常氨酰化。使用来自这些中国家庭的有症状和无症状成员和对照受试者的淋巴母细胞样细胞系，我们发现仅携带m.7511 A>G或p.191 Gly>瓦尔突变的细胞系分别显示相对轻度的tRNA（Ser（UCN））或tRNA（Tyr）代谢缺陷。然而，与仅携带m.7511 A>G或p.191 Gly>瓦尔突变的细胞系相比，携带m.7511 A>G和p.191 Gly>瓦尔突变的细胞系显示出更严重的缺陷性氨酰化和更低的tRNA（Ser（UCN））和tRNA（Tyr）水平、异常氨酰化以及更低的其他tRNA水平，包括tRNA（Thr）、tRNALys、tRNA（Leu（UUR））和tRNA（Ser（AGY））。此外，含有m.7511 A>G和p.191 Gly>瓦尔突变的突变细胞系表现出线粒体翻译、呼吸、线粒体ATP和膜电位水平的更大降低，沿着活性氧产生的增加。我们的研究结果提供了分子水平的见解，从tRNA（Ser（UCN））和线粒体YARS突变之间的协同作用所产生的母系遗传性耳聋的病理生理学。
Nuclear modifier genes have been proposed to modify the phenotypic expression of mitochondrial DNA mutations. Using a targeted exome sequencing approach, here we found that the p.191Gly>Val mutation in mitochondrial tyrosyl-tRNA synthetase 2 (YARS2) interacts with the tRNA(Ser(UCN)) 7511A>G mutation in causing deafness. Strikingly, members of a Chinese family bearing both YARS2 p.191Gly>Val and m.7511A>G mutations displayed much higher penetrance of deafness than those pedigrees carrying only the m.7511A>G mutation. The m.7511A>G mutation changed the A4:U69 base pairing to G4:U69 pairing at the aminoacyl acceptor stem of tRNA(Ser(UCN)) and perturbed tRNA(Ser(UCN)) structure and function, including an increased melting temperature, altered conformation, instability, and aberrant aminoacylation of mutant tRNA. Using lymphoblastoid cell lines derived from symptomatic and asymptomatic members of these Chinese families and control subjects, we show that cell lines harboring only the m.7511A>G or p.191Gly>Val mutation revealed relatively mild defects in tRNA(Ser(UCN)) or tRNA(Tyr) metabolism, respectively. However, cell lines harboring both m.7511A>G and p.191Gly>Val mutations displayed more severe defective aminoacylations and lower tRNA(Ser(UCN)) and tRNA(Tyr) levels, aberrant aminoacylation, and lower levels of other tRNAs, including tRNA(Thr), tRNALys, tRNA(Leu(UUR)), and tRNA(Ser(AGY)), than those in the cell lines carrying only the m.7511A>G or p.191Gly>Val mutation. Furthermore, mutant cell lines harboring both m.7511A>G and p.191Gly>Val mutations exhibited greater decreases in the levels of mitochondrial translation, respiration, and mitochondrial ATP and membrane potentials, along with increased production of reactive oxygen species. Our findings provide molecular-level insights into the pathophysiology of maternally transmitted deafness arising from the synergy between tRNA(Ser(UCN)) and mitochondrial YARS mutations.