Riboswitchcontrolled

Riboswitch-controlled describes gene expression or RNA function that is regulated by riboswitches, RNA elements that bind small molecules and alter RNA structure to influence downstream processes. Riboswitches are typically located in the 5' untranslated region of bacterial mRNAs but are also found in some eukaryotes. Upon ligand binding, a riboswitch undergoes a conformational change that can promote or prevent formation of secondary structures affecting transcription termination, translation initiation, splicing, or RNA stability.

Mechanisms of riboswitch-controlled regulation include transcriptional attenuation, in which ligand-induced folding creates a terminator hairpin; translational control, where access to the ribosome binding site is modulated; and self-cleavage in the case of ribozyme-type riboswitches such as the glmS element. Natural ligands include metabolites like thiamine pyrophosphate, flavin mononucleotide, adenine, and guanine, and riboswitches contribute to homeostatic feedback in metabolic pathways.

Riboswitch-controlled systems have practical importance in synthetic biology and biotechnology as programmable regulatory modules and biosensors, and they are investigated as potential antimicrobial targets because disrupting essential riboswitch function can impair bacterial growth. Study of riboswitch-controlled regulation sheds light on the evolutionary plasticity of RNA and the broader roles of RNA structure in gene expression control.