One transcript, two functions: the emerging roles of dual-function RNAs

Bacteria use small regulatory RNAs (sRNAs) and small proteins to change gene expression and modulate cellular processes in response to changing environmental conditions. In addition, several transcripts have been reported to combine base-pairing sRNA activities and coding capacity. These transcripts are known as dual-function RNAs. In some cases, the sRNA and the protein operate within the same pathway, while in other cases, they modulate separate processes in the cell. Thereby, dual-function RNAs enable bacteria to adjust their gene expression and physiology at multiple levels, which can have synergistic regulatory effects or help to synchronize the output of cellular pathways. In this review, we summarized the regulatory and physiological roles of dual-function RNAs in bacteria, including their roles in cell density, virulence, stress response, and metabolism. In addition, we discuss open challenges and possible future applications for harnessing dual regulators for precise gene expression control in bacteria.