Riboswitches in regulation of Rho-dependent transcription termination

Highlights

Some riboswitches use Rho termination factor to attenuate transcription.

Rho monitors the conformational state of the nascent RNA.

Binding of ligands by riboswitch RNAs determines Rho loading and ATPase activation.

Abstract

Riboswitches are RNA sensors of small metabolites and ions that regulate gene expression in response to environmental changes. In bacteria, the riboswitch sensor domain usually controls the formation of a strong RNA hairpin that either functions as a potent transcription terminator or sequesters a ribosome-binding site. A recent study demonstrated a novel mechanism by which a riboswitch controls Rho-dependent transcription termination. This riboswitch mechanism is likely a widespread mode of gene regulation that determines whether a protein effector is able to attenuate transcription. This article is part of a Special Issue entitled: Riboswitches.