Due to the high exposition to changing environmental conditions, bacteria have developed many mechanisms enabling immediate adjustments of gene expression. In many cases, the required speed and plasticity of the response are provided by RNA-dependent regulatory mechanisms. This is possible due to the very high dynamics and flexibility of an RNA structure, which provide the necessary sensitivity and specificity for efficient sensing and transduction of environmental signals. In this review, we will discuss the current knowledge about known bacterial regulatory mechanisms which rely on RNA structure. To better understand the structure-driven modulation of gene expression, we describe the basic theory on RNA structure folding and dynamics. Next, we present examples of multiple mechanisms employed by RNA regulators in the control of bacterial transcription and translation.

Chemical probing, for decades, has been one of the most popular tools for studying the secondary structure of RNA molecules. Recently, protocols for simultaneous analysis of multiple RNAs have been developed, enabling in vivo transcriptome-wide interrogation of the RNA structure dynamics. One of the most popular methods is the selective 2′-hydroxyl acylation analyzed by primer extension and mutational profiling (SHAPE-MaP). In this study, we describe the evaluation of this protocol by addressing the influence of the reverse transcription enzymes, buffer conditions, and chemical probes on the properties of the cDNA library and the quality of mutational profiling-derived structural signals. Our results reveal a SuperScript IV (SSIV) reverse transcriptase as a more efficient enzyme for mutational profiling of SHAPE adducts and shed new light on the role of Mn²⁺ cations in the modulation of SSIV readthrough efficiency.

In recent years, Term-seq became a standard experimental approach for high-throughput identification of 3’ ends of bacterial transcripts. It was widely adopted to study transcription termination events and 3’ maturation of bacterial RNAs. Despite widespread utilization, a universal bioinformatics toolkit for comprehensive analysis of Term-seq sequencing data is still lacking. Here, we describe TERMITe , a novel method for the identification of stable 3’ RNA ends based on bacterial Term-seq data. TERMITe works with data obtained from both currently available Term-seq protocols and provides robust identification of the 3’ RNA termini. Unique features of TERMITe include the calculation of the transcription termination efficiency using matched RNA-seq data and the comprehensive annotation of the identified 3’ RNA ends, allowing functional analysis of the results. We have applied TERMITe to the comparative analysis of experimentally validated intrinsic terminators spanning different species across the bacterial domain of life, revealing substantial differences in their sequence and secondary structure. We also provide a complete atlas of experimentally validated intrinsic transcription termination sites for 13 bacterial species, including Escherichia coli, Bacillus subtilis, Listeria monocytogenes, Enterococcus faecalis, Synechocystis sp ., Streptomyces clavuligerus, Streptomyces griseus, Streptomyces coelicolor, Streptomyces avermitilis, Streptomyces lividans, Streptomyces tsukubaensis, Streptomyces venezuelae , and Zymomonas mobilis .