哺乳动物 NSUN2 将 5-甲基胞嘧啶引入线粒体 tRNA。
Mammalian NSUN2 introduces 5-methylcytidines into mitochondrial tRNAs.
机构信息
Department of Chemistry and Biotechnology, Graduate School of Engineering, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Faculty of Pharmaceutical Sciences, Hokkaido University, Hokkaido 060-0812, Japan.
出版信息
Nucleic Acids Res. 2019 Sep 19;47(16):8734-8745. doi: 10.1093/nar/gkz575.
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 (m5C) at positions 48-50 in eight mouse and six human mt-tRNAs. We also confirmed the absence of m5C in mt-tRNAs isolated from Nsun2 knockout (KO) mice, as well as from NSUN2 KO human culture cells. In addition, we successfully reconstituted m5C 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 m5C 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.
线粒体 tRNA（mt-tRNA）的转录后修饰在产生呼吸链复合物的线粒体蛋白合成中起着关键作用。在这项研究中，我们利用质谱分析来绘制 8 种小鼠和 6 种人类 mt-tRNA 中位置 48-50 的 5-甲基胞嘧啶（m5C）。我们还证实了 Nsun2 敲除（KO）小鼠和 NSUN2 KO 人类培养细胞中分离的 mt-tRNA 中不存在 m5C。此外，我们还成功地在 S-腺苷甲硫氨酸存在的情况下，利用 NSUN2 蛋白在 mt-tRNA 的位置 48-50 上重新构成 m5C。尽管 NSUN2 主要定位于细胞核，并将 m5C 引入细胞质 tRNA 和 mRNA 中，但结构照明显微镜清楚地显示 NSUN2 焦点位于线粒体内部。这些观察结果为 NSUN2 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。
Zotero 插件