Transfer RNA-derived small RNAs (tsRNAs) are an emerging class of small RNAs, yet their regulatory roles have not been well understood. Here we studied the molecular mechanisms and consequences of tsRNA-mediated regulation in Drosophila. By analyzing 495 public small RNA libraries, we demonstrate that most tsRNAs are conserved, prevalent and abundant in Drosophila. By carrying out mRNA sequencing and ribosome profiling of S2 cells transfected with single-stranded tsRNA mimics and mocks, we show that tsRNAs recognize target mRNAs through conserved complementary sequence matching and suppress target genes by translational inhibition. The target prediction suggests that tsRNAs preferentially suppress translation of the key components of the general translation machinery, which explains how tsRNAs inhibit the global mRNA translation. Serum starvation experiments confirm tsRNAs participate in cellular starvation responses by preferential targeting the ribosomal proteins and translational initiation or elongation factors. Knock-down of AGO2 in S2 cells under normal and starved conditions reveals a dependence of the tsRNA-mediated regulation on AGO2. We also validated the repressive effects of representative tsRNAs on cellular global translation and specific targets with luciferase reporter assays. Our study suggests the tsRNA-mediated regulation might be crucial for the energy homeostasis and the metabolic adaptation in the cellular systems.

中文翻译：

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果蝇tsRNAs通过反义配对优先抑制通用翻译机制并参与细胞饥饿反应

源自转移RNA的小RNA（tsRNA）是一类新兴的小RNA，但其调控作用尚未得到很好的了解。在这里，我们研究了果蝇中tsRNA介导的调控的分子机制和后果。通过分析495个公共小RNA库，我们证明了大多数tsRNA在果蝇中都是保守的，普遍的和丰富的。通过对单链tsRNA模拟物和模拟物转染的S2细胞进行mRNA测序和核糖体分析，我们显示tsRNA通过保守的互补序列匹配识别靶mRNA，并通过翻译抑制抑制靶基因。目标预测表明，tsRNAs优先抑制通用翻译机制中关键成分的翻译，这解释了tsRNAs如何抑制全局mRNA的翻译。血清饥饿实验证实tsRNA通过优先靶向核糖体蛋白和翻译起始或延伸因子参与细胞饥饿反应。击倒AGO2在正常和饥饿的条件下，S2细胞中的Aβ2表达揭示了tsRNA介导的调节对AGO2的依赖性。我们还验证了代表性的tsRNA对荧光素酶报告基因检测对细胞整体翻译和特定靶标的抑制作用。我们的研究表明，tsRNA介导的调节对于细胞系统中的能量稳态和代谢适应可能至关重要。