Mechanistic insights into mitochondrial tRNA
| Autor: | Yanchun, Ji, Zhipeng, Nie, Feilong, Meng, Cuifang, Hu, Hui, Chen, Lihao, Jin, Mengquan, Chen, Minglian, Zhang, Juanjuan, Zhang, Min, Liang, Meng, Wang, Min-Xin, Guan |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
autophagy
RNA Mitochondrial RNA Stability PARP poly ADP ribose polymerase oxidative phosphorylation Apoptosis RNA Transfer Ala LAMP1 lysosome-associated membrane glycoprotein 1 LHON Leber’s hereditary optic neuropathy Electron Transport Mitochondrial Proteins Adenosine Triphosphate ROS reactive oxidative species Humans OCR oxygen consumption rate RNA Processing Post-Transcriptional A73 adenosine at position 73 mDNA mitochondrial DNA Membrane Potential Mitochondrial mitochondrial tRNA 3’-end metabolisms Base Sequence OXPHOS oxidative phosphorylation system Mitophagy Cytochromes c TBE Tris-borate-EDTA RGC retinal ganglion cell Mitochondria Mutation Nucleic Acid Conformation Transfer RNA Aminoacylation Leber’s hereditary optic neuropathy Reactive Oxygen Species TRNT1 tRNA nucleotidyltransferase Research Article |
| Zdroj: | The Journal of Biological Chemistry |
| ISSN: | 1083-351X |
| Popis: | Mitochondrial tRNA 3’-end metabolism is critical for the formation of functional tRNAs. Deficient mitochondrial tRNA 3’-end metabolism is linked to an array of human diseases, including optic neuropathy, but their pathophysiology remains poorly understood. In this report, we investigated the molecular mechanism underlying the Leber’s hereditary optic neuropathy (LHON)-associated tRNAAla 5587A>G mutation, which changes a highly conserved adenosine at position 73 (A73) to guanine (G73) on the 3’-end of the tRNA acceptor stem. The m.5587A>G mutation was identified in three Han Chinese families with suggested maternal inheritance of LHON. We hypothesized that the m.5587A>G mutation altered tRNAAla 3’-end metabolism and mitochondrial function. In vitro processing experiments showed that the m.5587A>G mutation impaired the 3’-end processing of tRNAAla precursors by RNase Z and inhibited the addition of CCA by tRNA nucleotidyltransferase (TRNT1). Northern blot analysis revealed that the m.5587A>G mutation perturbed tRNAAla aminoacylation, as evidenced by decreased efficiency of aminoacylation and faster electrophoretic mobility of mutated tRNAAla in these cells. The impact of m.5587A>G mutation on tRNAAla function was further supported by increased melting temperature, conformational changes, and reduced levels of this tRNA. Failures in tRNAAla metabolism impaired mitochondrial translation, perturbed assembly and activity of oxidative phosphorylation complexes, diminished ATP production and membrane potential, and increased production of reactive oxygen species. These pleiotropic defects elevated apoptotic cell death and promoted mitophagy in cells carrying the m.5587A>G mutation, thereby contributing to visual impairment. Our findings may provide new insights into the pathophysiology of LHON arising from mitochondrial tRNA 3’-end metabolism deficiency. |
| Databáze: | OpenAIRE |
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