Scholarlink

<p>The RNA modification 5-formylcytidine (f5C) is poorly explored in mammals. Low f5C levels reported in mRNA may reflect spurious 5-methylcytidine (m5C) oxidation or targeted demethylation by TET or ALKBH1 dioxygenases. We analyzed f5C in RNA of mouse embryonic stem cells (mESCs) using LC-MS/MS and chemical-assisted sequencing. We reveal that the previously reported pyridine-borane-sequencing misidentifies N4-acetylcytidine (ac4C) and unmodified, hyper-reactive cytidines in a <b>C</b>UMC context as f5C. To overcome these limitations, we developed FIBo-seq with enhanced specificity and sensitivity for f5C-sequencing. We find no evidence for a role of TET enzymes in generating f5C, unlike for ALKBH1. Moreover, no f5C sites are detectable in mRNA. Instead, the bulk of mammalian f5C resides in the well-established mitochondrial tRNA Methionine (<i>mt-tRNAMet</i>) and is mediated by ALKBH1. The results argue against an instructive function for f5C outside tRNA in mammals.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

5-Formylcytosine is not a prevalent RNA modification in mammalian cells

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年11月11日

查看全文
  • Jasmin A. Dehnen,
  • Alexander V. Gopanenko,
  • Carola Scholz,
  • Michael U. Musheev,
  • Christof Niehrs

摘要

The RNA modification 5-formylcytidine (f5C) is poorly explored in mammals. Low f5C levels reported in mRNA may reflect spurious 5-methylcytidine (m5C) oxidation or targeted demethylation by TET or ALKBH1 dioxygenases. We analyzed f5C in RNA of mouse embryonic stem cells (mESCs) using LC-MS/MS and chemical-assisted sequencing. We reveal that the previously reported pyridine-borane-sequencing misidentifies N4-acetylcytidine (ac4C) and unmodified, hyper-reactive cytidines in a CUMC context as f5C. To overcome these limitations, we developed FIBo-seq with enhanced specificity and sensitivity for f5C-sequencing. We find no evidence for a role of TET enzymes in generating f5C, unlike for ALKBH1. Moreover, no f5C sites are detectable in mRNA. Instead, the bulk of mammalian f5C resides in the well-established mitochondrial tRNA Methionine (mt-tRNAMet) and is mediated by ALKBH1. The results argue against an instructive function for f5C outside tRNA in mammals.