G-Quadruplex Visualization in Cells via Antibody and Fluorescence Probe.

G-quadruplexes (G4s) are noncanonical nucleic acids structures involved in key regulatory and pathological roles in eukaryotes, prokaryotes, and viruses: the development of specific antibodies and fluorescent probes represent an invaluable tool to understand their biological relevance. We here present three protocols for the visualization of G4s in cells, both uninfected and HSV-1 infected, using a specific antibody and a fluorescent G4 ligand, and the effect of the fluorescent ligand on a G4 binding protein, nucleolin, upon binding of the molecule to the nucleic acids structure.