Non-coding RNA regulation in pathogenic bacteria located inside eukaryotic cells

Abstract

Intracellular bacterial pathogens have evolved distinct lifestyles inside eukaryotic cells. Some pathogens coexist with the infected cell in an obligate intracellular state, whereas others transit between the extracellular and intracellular environment. Adaptation to these intracellular lifestyles is regulated in both space and time. Non-coding small RNAs (sRNAs) are post-transcriptional regulatory molecules that fine-tune important processes in bacterial physiology including cell envelope architecture, intermediate metabolism, bacterial communication, biofilm formation, and virulence. Recent studies have shown production of defined sRNA species by intracellular bacteria located inside eukaryotic cells. The molecules targeted by these sRNAs and their expression dynamics along the intracellular infection cycle remain, however, poorly characterized. Technical difficulties linked to the isolation of “intact” intracellular bacteria from infected host cells might explain why sRNA regulation in these specialized pathogens is still a largely unexplored field. Transition from the extracellular to the intracellular lifestyle provides an ideal scenario in which regulatory sRNAs are intended to participate; so much work must be done in this direction. This review focuses on sRNAs expressed by intracellular bacterial pathogens during the infection of eukaryotic cells, strategies used with these pathogens to identify sRNAs required for virulence, and the experimental technical challenges associated to this type of studies. We also discuss varied techniques for their potential application to study RNA regulation in intracellular bacterial infections.

Comparative Genomics ofH. pyloriand Non-PyloriHelicobacterSpecies to Identify New Regions Associated with Its Pathogenicity and Adaptability

“…Noncoding small RNAs act as posttranscriptional regulators that fine-tune important physiological processes in pathogens to adapt dynamic, intricate environment [75, 76]. To investigate the regulatory roles of the putative unique sRNAs, we mapped them to the genome of H. pylori 26695 [76].…”

A comparative study of sequence- and structure-based features of small RNAs and other RNAs of bacteria

“…The present study is focused on small RNAs (sRNAs), which are generally untranslated (with few exceptions), encoded in the 'empty' intergenic regions of bacterial chromosomes 2,3 and reported to perform a myriad of molecular functions regulating bacterial physiology, cell envelope architecture, intermediate metabolism, cell-cell communication, biofilm formation and virulence. 1,4,5 Bacterial sRNAs are shown to exert their role by base-pairing with the target mRNAs or by modulating protein functions. 1,5,6 However, bifunctional sRNAs with roles in translation and post-transcriptional regulation have also been documented.…”

RNA‐mediated signal perception in pathogenic bacteria

“…The concerted control of virulence factors has for long been shown to be organized by regulatory proteins. However, during the last decades, regulatory RNAs have been shown to control important aspects of virulence factor expression and pathogenicity in bacteria . Instead of just passively awaiting translation, bacterial mRNAs interact with regulatory RNAs, bind specific metabolites, or respond to other environmental cues.…”