RNA-seq and Ribo-seq of WT and METTL5 KO mECS.. RNA-seq and Ribo-seq of WT and METTL5 KO mECS.

Covalent chemical modifications of cellular RNAs directly impact all biological processes. However, our mechanistic understanding of the enzymes catalysing these modifications, their substrates and biological functions remains vague. Here, we undertook a systematic screen to uncover new RNA methyltransferases. We demonstrate that the methyltransferase-like 5 (METTL5) protein catalyses m6A in 18S rRNA at position A1832. We report that absence of Mettl5 in mouse embryonic stem cells (mESCs) results in a changes gene expression, decrease in translation rate, spontaneous loss of pluripotency and compromised differentiation potential. Mice lacking METTL5 recapitulate symptoms of patients with METTL5 mutations, thereby providing a new mouse disease model. Overall, our work highlights the importance of m6A in rRNA in stemness, differentiation, development and diseases. Overall design: RNA and Riob-seq of WT and METTL5 KO mESC in biological replicates.

细胞RNA的共价化学修饰直接参与调控所有生物学过程。然而，当前学界对催化此类修饰的酶、其底物及生物学功能的机制性认知仍较为模糊。本研究通过系统性筛选发掘新型RNA甲基转移酶，证实甲基转移酶样5（methyltransferase-like 5, METTL5）可催化18S核糖体RNA（18S rRNA）A1832位点的m6A修饰。研究发现，小鼠胚胎干细胞（mouse embryonic stem cells, mESCs）中METTL5的缺失会引发基因表达改变、翻译速率下降、多能性自发丧失以及分化潜能受损。METTL5敲除小鼠可重现携带METTL5突变患者的临床病症，由此构建出新型小鼠疾病模型。综上，本研究揭示了rRNA上的m6A修饰在干细胞干性、分化、发育及疾病发生中的关键作用。实验设计：对野生型（wild type, WT）与METTL5敲除（knockout, KO）小鼠胚胎干细胞（mESCs）进行生物学重复的RNA测序及Riob-seq检测。