Quendera Ana P, Seixas André F, Dos Santos Ricardo F, Santos Inês, Silva João P N, Arraiano Cecília M, Andrade José M
Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
Front Mol Biosci. 2020 May 13;7:78. doi: 10.3389/fmolb.2020.00078. eCollection 2020.
Small non-coding RNAs (sRNAs) are critical post-transcriptional regulators of gene expression. Distinct RNA-binding proteins (RBPs) influence the processing, stability and activity of bacterial small RNAs. The vast majority of bacterial sRNAs interact with mRNA targets, affecting mRNA stability and/or its translation rate. The assistance of RNA-binding proteins facilitates and brings accuracy to sRNA-mRNA basepairing and the RNA chaperones Hfq and ProQ are now recognized as the most prominent RNA matchmakers in bacteria. These RBPs exhibit distinct high affinity RNA-binding surfaces, promoting RNA strand interaction between a -encoding sRNA and its mRNA target. Nevertheless, some organisms lack ProQ and/or Hfq homologs, suggesting the existence of other RBPs involved in sRNA function. Along this line of thought, the global regulator CsrA was recently shown to facilitate the access of an sRNA to its target mRNA and may represent an additional factor involved in sRNA function. Ribonucleases (RNases) can be considered a class of RNA-binding proteins with nucleolytic activity that are responsible for RNA maturation and/or degradation. Presently RNase E, RNase III, and PNPase appear to be the main players not only in sRNA turnover but also in sRNA processing. Here we review the current knowledge on the most important bacterial RNA-binding proteins affecting sRNA activity and sRNA-mediated networks.
小非编码RNA（sRNA）是基因表达关键的转录后调节因子。不同的RNA结合蛋白（RBP）影响细菌小RNA的加工、稳定性和活性。绝大多数细菌sRNA与mRNA靶标相互作用，影响mRNA的稳定性和/或其翻译速率。RNA结合蛋白的协助促进了sRNA与mRNA的碱基配对并提高了准确性，RNA伴侣蛋白Hfq和ProQ现在被认为是细菌中最主要的RNA媒人。这些RBP表现出独特的高亲和力RNA结合表面，促进编码sRNA与其mRNA靶标之间的RNA链相互作用。然而，一些生物体缺乏ProQ和/或Hfq同源物，这表明存在其他参与sRNA功能的RBP。按照这一思路，全局调节因子CsrA最近被证明可促进sRNA接近其靶标mRNA，可能是参与sRNA功能的另一个因子。核糖核酸酶（RNase）可被视为一类具有核酸水解活性的RNA结合蛋白，负责RNA的成熟和/或降解。目前，RNase E、RNase III和PNPase似乎不仅是sRNA周转的主要参与者，也是sRNA加工的主要参与者。在这里，我们综述了目前关于影响sRNA活性和sRNA介导网络的最重要细菌RNA结合蛋白的知识。
