Abstract
It is increasingly apparent that noncoding RNAs (RNA sequences that do not go on to encode for proteins) have essential roles in cellular processes. Riboswitches are one type of noncoding RNA sequence found in untranslated regions of mRNAs. Many riboswitch RNAs undergo conformational change upon binding to a specific cellular metabolite. The interaction modulates expression of the adjacent coding region, which typically produces a protein enzyme required for synthesis of the metabolite, thereby providing an efficient feedback mechanism of genetic control. To date, riboswitches that bind to a diverse set of ligands have been identified in bacteria. Only one of these riboswitches has been identified in eukaryotic plants and fungi. We are interested in identifying riboswitches in animals. We are investigating the structure and function of a potential riboswitch conserved among a wide variety of species and thought to control polyamine biosynthesis. We hypothesize that the potential riboswitch RNAs from diverse organisms will bind specifically to ligand and demonstrate conformational change upon ligand binding. We are utilizing equilibrium dialysis to demonstrate specific binding of ligand and in-line probing to observe conformation changes in the RNAs. Our preliminary results indicate that the RNAs from diverse species possess similar binding ability. Future studies will investigate this conserved sequence element from other organisms using similar techniques. The identification of riboswitches amongst animals suggests that such RNAs could be therapeutic targets for modulating gene expression.