Until recently, gene expression was thought to be controlled mainly at the level of transcription initiation by repressor or activator proteins. In some cases, transcription elongation is controlled by a so-called attenuation mechanism that involves alternative base-pairing between different regions of an mRNA transcript. Recent data reveal that other mechanisms can regulate gene expression and involve RNAs that might act as antisense RNAs, sequestering molecules, or thermosensors. This review focuses on recent studies in bacterial pathogens in which a growing list of examples show that RNA can control virulence gene expression.
