Riboswitches are structural elements typically found in the untranslated regions of bacterial or eukaryotic mRNAs. These riboswitches generally dictate the gene expression of corresponding genes by interacting with small target molecules or metabolites. Binding of naturally occurring metabolites to the aptamer domain of riboswitch mRNA causes structural changes in the gene expression machinery that control expression levels. Researchers from The University of Manchester report the development of riboswitches that allow orthogonally selective, tunable, and dose-dependent control of gene expression in response to nonnatural synthetic small molecules.

Dixon et al. Reengineering orthogonally selective riboswitches. PNAS January 26, 2010 (DOI:10.1073/pnas.0911209107)