Riboswitches are regulatory noncoding RNAs, predominantly located in the 5′ untranslated region of mRNA, that can serve as molecular switches able to regulate the level of gene expression. This occurs through the conformational changes caused by binding to a specific metabolite. Riboswitches contain two structural domains: an aptamer domain that senses and binds to a metabolite and an expression platform that undergoes a conformational change in response to aptamer-ligand binding resulting in regulation of expression of downstream gene. In addition to natural riboswitches found in living organisms, a variety of synthetic riboswitches that respond to nonnatural small molecules have been developed. Synthetic riboswitches can be engineered to regulate expression of any gene in response to any nonnatural molecule that is capable of being bound by RNA and is not toxic to cells. This feature demonstrates a strong possibility for RNA switches to serve as sensor entities for design and development of cell-based biosensors with a variety of different applications. This chapter gives an overview of riboswitch selection techniques, describes reporter systems for monitoring riboswitch activation and approaches for riboswitch tuning and performance optimization in order to fulfill biosensor requirements, and discusses riboswitch applications as sensor entities.
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Ascertaining auditors’ intentions to use blockchain technology: evidence from the Big 4 accountancy firms in Italy
