Fluorescent Indicator Displacement Assay for Ligand−RNA Interactions

摘要

Since the discovery of a role for RNA in modulating genenexpression, functional RNA has become an attractive drug target.n1nLigand RNA interactions have been studied using covalent labelingnof either the ligand or RNA with fluorescent dyes and bynimmobilization on sensing devices.n2nHowever, it is desirable tonavoid chemical modification of the ligand or RNA, as this maynalter their native secondary and tertiary structures.n3nDisplacementnassaysn4–6nsatisfy this criterion because neither covalent labeling nornimmobilization is necessary. We describe a fluorescent indicatorndisplacement assay for ligand RNA interactions based on a novelnfluorescent indicator, a 2,7-disubstituted 9H-xanthen-9-one deriva-ntive (X2S) (Figure 1). X2S is nonfluorescent when bound to RNAnbut fluoresces when it is displaced from RNA.