Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins, CO, 80523, USA.
New England Biolabs Inc., Beverly, MA, 01915, USA.
Nat Commun. 2024 Aug 23;15(1):7272. doi: 10.1038/s41467-024-51410-w.
RNAs are often modified to invoke new activities. While many modifications are limited in frequency, restricted to non-coding RNAs, or present only in select organisms, 5-methylcytidine (mC) is abundant across diverse RNAs and fitness-relevant across Domains of life, but the synthesis and impacts of mC have yet to be fully investigated. Here, we map mC in the model hyperthermophile, Thermococcus kodakarensis. We demonstrate that mC is ~25x more abundant in T. kodakarensis than human cells, and the mC epitranscriptome includes ~10% of unique transcripts. T. kodakarensis rRNAs harbor tenfold more mC compared to Eukarya or Bacteria. We identify at least five RNA mC methyltransferases (R5CMTs), and strains deleted for individual R5CMTs lack site-specific mC modifications that limit hyperthermophilic growth. We show that mC is likely generated through partial redundancy in target sites among R5CMTs. The complexity of the mC epitranscriptome in T. kodakarensis argues that mC supports life in the extremes.
RNAs 经常被修饰以引发新的活性。虽然许多修饰的频率有限，仅限于非编码 RNA，或者只存在于某些生物体中，但 5-甲基胞嘧啶（mC）在各种 RNA 中都很丰富，在生命的各个领域都与适应性相关，但 mC 的合成和影响尚未得到充分研究。在这里，我们在模式嗜热菌 Thermococcus kodakarensis 中绘制 mC。我们证明 mC 在 T. kodakarensis 中的丰度比人类细胞高约 25 倍，并且 mC 转录组包括约 10%的独特转录本。与真核生物或细菌相比，T. kodakarensis 的 rRNA 中含有十倍以上的 mC。我们鉴定了至少五个 RNA mC 甲基转移酶（R5CMTs），并且缺失单个 R5CMTs 的菌株缺乏限制嗜热生长的特异性 mC 修饰。我们表明 mC 可能是通过 R5CMTs 之间在靶位点上的部分冗余产生的。T. kodakarensis 中 mC 转录组的复杂性表明 mC 支持极端条件下的生命。
