2'-O-Methylation (Nm) represents one of the most common RNA modifications. Nm affects RNA structure and function with crucial roles in various RNA-mediated processes ranging from RNA silencing, translation, self versus non-self recognition to viral defense mechanisms. Here, we identify two Nm methyltransferases (Nm-MTases) in Drosophila melanogaster (CG7009 and CG5220) as functional orthologs of yeast TRM7 and human FTSJ1. Genetic knockout studies together with MALDI-TOF mass spectrometry and RiboMethSeq mapping revealed that CG7009 is responsible for methylating the wobble position in tRNAPhe, tRNATrp and tRNALeu, while CG5220 methylates position C32 in the same tRNAs and also targets additional tRNAs. CG7009 or CG5220 mutant animals were viable and fertile but exhibited various phenotypes such as lifespan reduction, small RNA pathways dysfunction and increased sensitivity to RNA virus infections. Our results provide the first detailed characterization of two TRM7 family members in Drosophila and uncover a molecular link between enzymes catalyzing Nm at specific tRNAs and small RNA-induced gene silencing pathways.

中文翻译：

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通过二重TRM7 / FTSJ1蛋白进行的tRNA 2'-O-甲基化可调节果蝇中的小RNA沉默。

2'-O-甲基化（Nm）代表最常见的RNA修饰之一。Nm在各种RNA介导的过程中起着至关重要的作用，从而影响RNA的结构和功能，这些过程包括从RNA沉默，翻译，自我与非自我识别到病毒防御机制。在这里，我们确定果蝇（CG7009和CG5220）中的两个Nm甲基转移酶（Nm-MTases）作为酵母TRM7和人类FTSJ1的功能直系同源物。遗传敲除研究以及MALDI-TOF质谱和RiboMethSeq绘图显示，CG7009负责甲基化tRNAPhe，tRNATrp和tRNALeu中的摆动位置，而CG5220甲基化同一tRNA中的C32位置，并且还靶向其他tRNA。CG7009或CG5220突变动物既活又肥沃，但表现出各种表型，例如寿命缩短，小RNA通路功能障碍，并增加了对RNA病毒感染的敏感性。我们的结果提供了果蝇中两个TRM7家族成员的首次详细表征，并揭示了在特定tRNA上催化Nm的酶与小RNA诱导的基因沉默途径之间的分子联系。