3untranslated regions: regulation at the end of the road

Post-transcriptional gene regulation in bacteria plays a major role in the adaptation of bacterial cells to the changing conditions encountered in the environment. In bacteria, most of the regulation at the level of mRNA seems to be targeting the 5untranslated regions where accessibility to the ribosome-binding site can be modulated to alter gene expression. In recent years, the role of 3untranslated regions has gained attention also as a site for post-transcriptional regulation. In addition to be a source of trans-encoded small RNAs, the 3untranslated regions can be targets to modulate gene expression. Taking recent findings in the post-transcriptional regulation of the hilD gene, encoding for the main regulator of virulence in Salmonella enterica serovar Typhimurium, we highlight the role of 3untranslated regions as targets of post-transcriptional regulation mediated by small RNAs and discuss the implications of transcriptional elongation in the 3UTR-mediated regulation in bacteria.