Visualization of G-quadruplexes by using a BODIPY-labeled macrocyclic heptaoxazole.

A BODIPY-labeled macrocyclic heptaoxazole, L1BOD-7OTD, was developed as a fluorescent ligand for G-quadruplexes. The results of the study show that L1BOD-7OTD both selectively induces the formation of intramolecular G-quadruplexes from some G-quadruplex forming oligonucleotides (GFOs). In addition, the labelled macrocyclic heptaozaxole strongly binds to and stabilizes intramolecular G-quadruplexes. Moreover, this substance can be used to directly visualize the G-quadruplexes in the form of green fluorescence. Finally, the possibility that G-quadruplexes form in the cells was demonstrated by using of L1BOD-7OTD.