Mammalian NSUN2 introduces 5-methylcytidines into mitochondrial tRNAs
Mammalian NSUN2 introduces 5-methylcytidines into mitochondrial tRNAs
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DOI：
10.1093/nar/gkz575
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发表时间：
2019-09-19
影响因子：
14.9
通讯作者：
Suzuki, Tsutomu
中科院分区：
文献类型：
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作者：
Shinoda, Saori;Kitagawa, Sho;Suzuki, Tsutomu
线粒体tRNA（mt-tRNA）的转录后修饰在线粒体蛋白质合成中起关键作用，线粒体蛋白质合成产生呼吸链复合物。在这项研究中，我们利用质谱分析的优势，在8个小鼠和6个人类mt-tRNA的位置48-50定位5-甲基胞苷（m（5）C）。我们还证实了从Nsun 2敲除（KO）小鼠以及从Nsun 2 KO人培养细胞中分离的m（5）C inmt-tRNA的缺失。此外，我们成功地重建m（5）C在位置48-50的mt-tRNA在体外与NSUN 2蛋白在S-腺苷甲硫氨酸的存在。虽然NSUN 2主要定位于细胞核并将m（5）C引入细胞质tRNA和mRNA，但结构照明显微镜清楚地显示了线粒体内的NSUN 2病灶。这些观察结果为NSUN 2在线粒体功能的生理学和病理学中的作用提供了新的见解。
Post-transcriptional modifications in mitochondrial tRNAs (mt-tRNAs) play critical roles in mitochondrial protein synthesis, which produces respiratory chain complexes. In this study, we took advantage of mass spectrometric analysis to map 5-methylcytidine (m(5)C) at positions 48-50 in eight mouse and six human mt-tRNAs. We also confirmed the absence of m(5)C inmt-tRNAs isolated from Nsun2 knockout (KO) mice, as well as from NSUN2 KO human culture cells. In addition, we successfully reconstituted m(5)C at positions 48-50 of mt-tRNA in vitro with NSUN2 protein in the presence of S-adenosylmethionine. Although NSUN2 is predominantly localized to the nucleus and introduces m(5)C into cytoplasmic tRNAs and mRNAs, structured illumination microscopy clearly revealed NSUN2 foci inside mitochondria. These observations provide novel insights into the role of NSUN2 in the physiology and pathology of mitochondrial functions.