Megel Cyrille, Morelle Geoffrey, Lalande Stéphanie, Duchêne Anne-Marie, Small Ian, Maréchal-Drouard Laurence
Institut de Biologie Moléculaire des Plantes, CNRS, Associated with University of Strasbourg, 12 rue du Général Zimmer, F-67084 Strasbourg Cedex, France.
Australian Research Council Centre of Excellence in Plant Energy Biology, the University of Western Australia, Crawley WA6009, Australia.
Int J Mol Sci. 2015 Jan 15;16(1):1873-93. doi: 10.3390/ijms16011873.
Beyond their central role in protein synthesis, transfer RNAs (tRNAs) have many other crucial functions. This includes various roles in the regulation of gene expression, stress responses, metabolic processes and priming reverse transcription. In the RNA world, tRNAs are, with ribosomal RNAs, among the most stable molecules. Nevertheless, they are not eternal. As key elements of cell function, tRNAs need to be continuously quality-controlled. Two tRNA surveillance pathways have been identified. They act on hypo-modified or mis-processed pre-tRNAs and on mature tRNAs lacking modifications. A short overview of these two pathways will be presented here. Furthermore, while the exoribonucleases acting in these pathways ultimately lead to complete tRNA degradation, numerous tRNA-derived fragments (tRFs) are present within a cell. These cleavage products of tRNAs now potentially emerge as a new class of small non-coding RNAs (sncRNAs) and are suspected to have important regulatory functions. The tRFs are evolutionarily widespread and created by cleavage at different positions by various endonucleases. Here, we review our present knowledge on the biogenesis and function of tRFs in various organisms.
除了在蛋白质合成中发挥核心作用外，转运RNA（tRNA）还有许多其他关键功能。这包括在基因表达调控、应激反应、代谢过程和引发逆转录等方面的各种作用。在RNA世界中，tRNA与核糖体RNA一样，是最稳定的分子之一。然而，它们并非永恒不变。作为细胞功能的关键要素，tRNA需要持续进行质量控制。现已确定了两条tRNA监测途径。它们作用于修饰不足或加工错误的前体tRNA以及缺乏修饰的成熟tRNA。本文将简要概述这两条途径。此外，虽然在这些途径中起作用的外切核糖核酸酶最终会导致tRNA完全降解，但细胞内存在大量tRNA衍生片段（tRF）。这些tRNA的切割产物现在可能成为一类新的小非编码RNA（sncRNA），并被怀疑具有重要的调控功能。tRF在进化上广泛存在，由各种内切核酸酶在不同位置切割产生。在这里，我们综述了目前关于tRF在各种生物体中的生物发生和功能的知识。
