International Journal of Clinical Research. 2021; 5: (3) ; 10.12208/j.ijcr.20210021 .
*通讯作者： 王建伟,单位：浙江大学医学院第二附属医院教育部肿瘤预防与干预重点实验室结直肠外科 浙江杭州；
5-甲基胞嘧啶(m5C)是一种丰富的核糖核酸（RNA）修饰，其存在于多种RNA中，包括细胞质和线粒体的核糖体RNA (rRNAs)和转移RNA (tRNAs)，以及信使RNA (mRNA)、增强子RNA (eRNAs)和一些非编码RNA。在真核生物中，RNA胞嘧啶的C5甲基化是由NOL1/NOP2/SUN结构域(NSUN)家族的酶以及DNA甲基转移酶同源物DNMT2催化的。近年来，甲基转移酶催化的底物RNA和修饰的靶核苷酸已经得到鉴定，结构分析和生化分析学为研究这些酶是如何实现靶特异性奠定了基础。这些酶的功能特征及其介导的修饰揭示了它们在线粒体和核基因表达的不同方面的重要作用。重要的是，这些发现使我们能够更好地理解编码m5C甲基转移酶的基因突变或这些酶的表达水平的改变所导致的一些疾病的分子基础。
5-methylcytosine (m5C) is a rich ribonucleic acid (RNA) modification, which exists in a variety of RNA, including cytoplasmic and mitochondrial ribosomal RNA(RRNAs) and transfer RNA(tRNAs), as well as messenger RNA(mRNA), enhancer RNA(Ernas) and some non-coding RNAs. In eukaryotes, C5 methylation of RNA cytosine is catalyzed by enzymes in the NOL1/NOP2/SUN domain (NSUN) family and DNA methyltransferase homologous DNMT2. In recent years, substrate RNA and modified target nucleotides catalyzed by methyltransferases have been identified, and structural and biochemical analyses have laid the foundation for the study of how these enzymes achieve target specificity. The functional characteristics of these enzymes and their mediated modifications reveal their important roles in different aspects of mitochondrial and nuclear gene expression. Importantly, these findings enable us to better understand the molecular basis of some diseases caused by mutations in the genes that encode M5C methyltransferase or by changes in the expression levels of these enzymes.
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