Gram-negative Bacteria's Small Non-coding RNAs: New Insights and Comprehensive Review of Mechanisms, Functions, and Potential Applications

Small non-coding RNAs (sRNAs) are a key part of gene expression regulation in bacteria. Many physiologic activities like adaptation to environmental stresses, antibiotic resistance, quorum sensing, and modulation of the host immune response are regulated directly or indirectly by sRNAs in gram-negative bacteria. Therefore, sRNAs can be considered as potentially useful therapeutic options. They have opened promising perspectives in the field of diagnosis of pathogens and treatment of infections caused by antibiotic-resistant organisms.Identification of sRNAs can be executed by sequence and expression-based methods. Moreover, computationally prediction of sRNAs using bioinformatic tools is developed in recent years, which helps to get more comprehensive data in combination with experimental approaches.Despite the valuable progresses in the last two decades, and discovery of new sRNAs, their exact role in biological pathways especially in corporation with other biomolecules involved in gene expression regulation such as RNA-binding proteins (RBPs), Riboswitches, and other sRNAs needs further investigation.Although there are many RNA databases that RNAcentral uses ۵۹ of them, the lack of a professional database to categorize current experimentally validated sRNAs in gram-negative pathogens is a gap. Here we review the present knowledge on most recent and important sRNAs and their regulatory mechanism, strengths and weaknesses of current methods of sRNAs identification, and at the end, demonstrate potential applications and new insights of sRNAs for future studies.