Extracellular RNAs participate in intercellular communication, and are being studied as promising minimally invasive diagnostic markers. Several studies in recent years showed that tRNA halves and distinct Y RNA fragments are abundant in the extracellular space, including in biofluids. While their regulatory and diagnostic potential has gained a substantial amount of attention, the biogenesis of these extracellular RNA fragments remains largely unexplored. Here, we demonstrate that these fragments are produced by RNase 1, a highly active secreted nuclease. We use RNA sequencing to investigate the effect of a null mutation of RNase 1 on the levels of tRNA halves and Y RNA fragments in the extracellular environment of cultured human cells. We complement and extend our RNA sequencing results with northern blots, showing that tRNAs and Y RNAs in the non-vesicular extracellular compartment are released from cells as full-length precursors and are subsequently cleaved to distinct fragments. In support of these results, formation of tRNA halves is recapitulated by recombinant human RNase 1 in our in vitro assay. These findings assign a novel function for RNase 1, and position it as a strong candidate for generation of tRNA halves and Y RNA fragments in biofluids.

中文翻译：

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RNase 1 的加工在细胞外环境中形成 tRNA 一半和不同的 Y RNA 片段。


细胞外 RNA 参与细胞间通讯，并且正在作为有前途的微创诊断标记物进行研究。近年来的多项研究表明，tRNA 半部和不同的 Y RNA 片段在细胞外空间（包括生物体液）中含量丰富。虽然它们的调控和诊断潜力引起了广泛关注，但这些细胞外 RNA 片段的生物发生在很大程度上仍未得到探索。在这里，我们证明这些片段是由 RNase 1（一种高活性的分泌性核酸酶）产生的。我们使用 RNA 测序来研究 RNase 1 的无效突变对培养的人类细胞的细胞外环境中 tRNA 半部和 Y RNA 片段水平的影响。我们用 Northern 印迹补充和扩展了我们的 RNA 测序结果，表明非囊泡细胞外区室中的 tRNA 和 Y RNA 作为全长前体从细胞中释放，随后被切割成不同的片段。为了支持这些结果，在我们的体外测定中，重组人 RNase 1 重现了 tRNA 半部的形成。这些发现为 RNase 1 赋予了新的功能，并将其定位为在生物体液中生成 tRNA 半部和 Y RNA 片段的有力候选者。