Regulatory RNAs as mediators of virulence gene expression in bacteria

Bacteria exploit functional diversity of RNAs in a wide range of regulatory mechanisms to control gene expression. In last few years, small RNA molecules have been discovered at a staggering rate in bacteria, mainly in Escherichia coli. While functions of many of these RNA molecules are still not known, several of them behave as key effectors of adaptive responses, such as environmental cue recognition, stress response, and virulence control. Most fascinating, perhaps, is the discovery that mRNAs behave as direct sensors of small molecules or of environmental cues. The astonishing diversity of RNA-dependent regulatory mechanisms is linked to the dynamic properties and versatility of the RNA structure. In this review, we relate several recent studies in different bacterial pathogens that illustrate the diverse roles of RNA to control virulence gene expression.