A near-infrared indicator for sensitive imaging of G-Quadruplexes in live cells.

G-quadruplexes (G4s), DNA or RNA structures formed by guanine-rich sequences, play indispensable regulatory roles in numerous biological processes. Here we develop a Near Infrared (NIR) fluorescence G4 indicator (TAQ) which enables activatable imaging of G4s in live cells. The indicator TAQ is merely emissive in aqueous solution and its fluorescence at 677 nm is remarkably enhanced in the presence of a typical hybrid G4 structure. TAQ broadly interacts with different G4 structures, exhibiting high selectivity toward G4s over single- or double-stranded nucleic acids. It is demonstrated that TAQ affords dynamic fluorescence response to G4 concentrations in the range of 5.0–600 nM with an estimated limit of detection of 0.51 nM. Live cell studies demonstrate that TAQ delivers intense fluorescence signals upon specific interaction with G4 structures. We further employ TAQ to track the dynamics of RNA/DNA G4s in live cells. This NIR fluorescence indicator could provide a valuable tool for interrogating the dynamics of G4 structures in live cells. [Display omitted] • A near infrared (NIR) fluorescence G4 indicator (TAQ) is reported for activatable imaging of G4s in live cells. • The NIR fluorescence probe exhibits high sensitivity and high selectivity toward G4s over other nucleic acids. • The NIR fluorescence probe is successfully introduced to track the dynamic changes of G4s in live cells. [ABSTRACT FROM AUTHOR]