Facile Expansion of the Variety of Orthogonal Ligand/Aptamer Pairs for Artificial Riboswitches.

An RNA aptamer that induces suitable conformational changes upon binding to a user-defined ligand allows us to artificially construct a riboswitch, a ligand-dependent and -acting gene regulatory RNA. Although such an aptamer can be obtained through selection, it is still challenging to rationally expand the variety of orthogonal ligand/aptamer (ligand/riboswitch) pairs. To achieve this in a facile, selection-free way, we herein focused on a specific type of ligand, 6-nt nanosized DNA (nDNA) and its aptamer that was previously selected to construct a eukaryotic artificial riboswitch.