Overexpression of mitochondrial histidyl-tRNA synthetase restores mitochondrial dysfunction caused by a deafness-associated tRNAHismutation

作者：Shasha Gong, Xiaoqiong Wang, Feilong Meng, Limei Cui, Qiuzi Yi, Qiong Zhao, Xiaohui Cang, Zhiyi Cai, Jun Qin Mo, Yong Liang, Min‐Xin Guan · 发表于：Journal of Biological Chemistry · 年份：2019 · DOI：10.1074/jbc.ra119.010998 · 被引用次数：24 · 研究领域：Mitochondrial Function and Pathology、RNA modifications and cancer、RNA and protein synthesis mechanisms

The deafness-associated m.12201T>C mutation affects the A5-U68 base-pairing within the acceptor stem of mitochondrial tRNA His . The primary defect in this mutation is an alteration in tRNA His aminoacylation. Here, we further investigate the molecular mechanism of the deafness-associated tRNA His 12201T>C mutation and test whether the overexpression of the human mitochondrial histidyl-tRNA synthetase gene ( HARS2 ) in cytoplasmic hybrid (cybrid) cells carrying the m.12201T>C mutation reverses mitochondrial dysfunctions. Using molecular dynamics simulations, we demonstrate that the m.12201T>C mutation perturbs the tRNA His structure and function, supported by decreased melting temperature, conformational changes, and instability of mutated tRNA. We show that the m.12201T>C mutation-induced alteration of aminoacylation tRNA His causes mitochondrial translational defects and respiratory deficiency. We found that the transfer of HARS2 into the cybrids carrying the m.12201T>C mutation raises the levels of aminoacylated tRNA His from 56.3 to 75.0% but does not change the aminoacylation of other tRNAs. Strikingly, HARS2 overexpression increased the steady-state levels of tRNA His and of noncognate tRNAs, including tRNA Ala , tRNA Gln , tRNA Glu , tRNA Leu(UUR) , tRNA Lys , and tRNA Met , in cells bearing the m.12201T>C mutation. This improved tRNA metabolism elevated the efficiency of mitochondrial translation, activities of oxidative phosphorylation complexes,...