Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.
New Phytol. 2024 Oct;244(2):571-587. doi: 10.1111/nph.20034. Epub 2024 Aug 26.
Aberrant RNA modifications can lead to dysregulated gene expression and impeded growth in plants. Ribosomal RNA (rRNA) constitutes a substantial portion of total RNA, while the precise functions and molecular mechanisms underlying rRNA modifications in plants remain largely elusive. Here, we elucidated the exclusive occurrence of the canonical RNA modification N-methyladenosine (mA) solely 18S rRNA, but not 25S rRNA. We identified a completely uncharacterized protein, ATMETTL5, as an Arabidopsis mA methyltransferase responsible for installing mA methylation at the 1771 site of the 18S rRNA. ATMETTL5 is ubiquitously expressed and localized in both nucleus and cytoplasm, mediating rRNA mA methylation. Mechanistically, the loss of ATMETTL5-mediated methylation results in attenuated translation. Furthermore, we uncovered the role of ATMETTL5-mediated methylation in coordinating blue light-mediated hypocotyl growth by regulating the translation of blue light-related messenger RNAs (mRNAs), specifically HYH and PRR9. Our findings provide mechanistic insights into how rRNA modification regulates ribosome function in mRNA translation and the response to blue light, thereby advancing our understanding of the role of epigenetic modifications in precisely regulating mRNA translation in plants.
异常的 RNA 修饰可导致基因表达失调和植物生长受阻。核糖体 RNA(rRNA)构成了总 RNA 的很大一部分，而 rRNA 修饰在植物中的精确功能和分子机制在很大程度上仍难以捉摸。在这里，我们阐明了规范的 RNA 修饰 N6-甲基腺苷(mA)仅存在于 18S rRNA 中，而不存在于 25S rRNA 中。我们鉴定了一个完全未被表征的蛋白，ATMETTL5，作为拟南芥 mA 甲基转移酶，负责在 18S rRNA 的 1771 位安装 mA 甲基化。ATMETTL5 广泛表达并定位于细胞核和细胞质中，介导 rRNA mA 甲基化。从机制上讲，ATMETTL5 介导的甲基化的缺失导致翻译减弱。此外，我们揭示了 ATMETTL5 介导的甲基化在协调蓝光介导的下胚轴生长中的作用，通过调节蓝光相关信使 RNA(mRNA)，特别是 HYH 和 PRR9 的翻译来实现。我们的研究结果提供了关于 rRNA 修饰如何调节核糖体功能在 mRNA 翻译和对蓝光反应中的机制见解，从而加深了我们对表观遗传修饰在精确调节植物中 mRNA 翻译中的作用的理解。
