A large variety of eukaryotic small structured POLIII-derived non-coding RNAs (ncRNAs) have been described in the past. However, for only few, e.g. 7SL and H1/MRP families, cellular functions are well understood. For the vast majority of these transcripts, cellular functions remain unknown. Recent findings on the role of Y RNAs and other POLIII-derived ncRNAs suggest an evolutionarily conserved function of these ncRNAs in the assembly and function of ribonucleoprotein complexes (RNPs). These RNPs provide cellular `machineries’, which are essential for guiding the fate and function of a variety of RNAs. In this review, we summarize current knowledge on the role of POLIII-derived ncRNAs in the assembly and function of RNPs. We propose that these ncRNAs serve as scaffolding factors that `chaperone’ RNA-binding proteins (RBPs) to form functional RNPs. In addition or associated with this role, some small ncRNAs act as molecular decoys impairing the RBP-guided control of RNA fate by competing with other RNA substrates. This suggests that POLIII-derived ncRNAs serve essential and conserved roles in the assembly of larger RNPs and thus the control of gene expression by indirectly guiding the fate of mRNAs and lncRNAs.

中文翻译：

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POLIII衍生的非编码RNA充当支架和诱饵。

过去已经描述了多种真核生物小结构的POLIII衍生非编码RNA（ncRNA）。但是，对于只有少数几个，例如7SL和H1 / MRP系列，细胞功能是众所周知的。对于这些转录物中的绝大多数，细胞功能仍然未知。Y RNA和其他POLIII衍生的ncRNA的作用的最新发现表明，这些ncRNA在核糖核蛋白复合物（RNP）的装配和功能中具有进化上保守的功能。这些RNP提供了细胞“机器”，对于指导各种RNA的命运和功能至关重要。在这篇综述中，我们总结了有关POLIII衍生ncRNA在RNP装配和功能中的作用的当前知识。我们建议这些ncRNA作为“伴侣” RNA结合蛋白（RBP）形成功能性RNP的支架因子。另外或与此角色相关联，一些小型ncRNA充当分子诱饵，通过与其他RNA底物竞争而破坏了RBP指导的RNA命运控制。这表明POLIII衍生的ncRNA在较大RNP的组装中起着至关重要的作用，因此通过间接指导mRNA和lncRNA的命运来控制基因表达。