Small RNAs regulate primary and secondary metabolism in gram-negative bacteria

A diverse palette of novel small regulatory RNAs (sRNAs) has been identified in bacteria in recent years, and many play important roles in regulating gene expression and adaptation to constantly changing physiological and metabolic needs. To date, more than a hundred sRNAs have been identified and characterized in gram-negative bacteria, with crucial and sometimes global regulatory functions that can easily rival protein regulators. The most studied and widely dispersed class of sRNAs in gram-negative bacteria act post-transcriptionally by base pairing to target mRNAs in order to effect positive or negative regulatory outcomes.