Dual-function RNA regulators in bacteria

► Dual-function sRNAs are found in both gram-negative and gram-positive bacteria. ► Highly conserved regions of sRNAs are most likely involved in mRNA regulation. ► The RNA chaperone Hfq is typically required only by sRNAs in gram-negative species. ► Peptides encoded by sRNAs may have physiologically distinct or redundant functions. ► Spatial organization of coding and regulatory RNA regions may affect function.