The interactions between a small molecule and G-quadruplexes are visualized by fluorescence lifetime imaging microscopy.
Guanine-rich oligonucleotides can fold into quadruple-stranded helical structures known as G-quadruplexes. Mounting experimental evidence has gathered suggesting that these non-canonical nucleic acid structures form in vivo and play essential biological roles. However, to date, there are no small-molecule optical probes to image G-quadruplexes in live cells. Herein, we report the design and development of a small fluorescent molecule, which can be used as an optical probe for G-quadruplexes. We demonstrate that the fluorescence lifetime of this new probe changes considerably upon interaction with different nucleic acid topologies. Specifically, longer fluorescence lifetimes are observed in vitro for G-quadruplexes than for double- and single-stranded nucleic acids. Cellular studies confirm that this molecule is cell permeable, has low cytotoxicity and localizes primarily in the cell nucleus. Furthermore, using fluorescence lifetime imaging microscopy, live-cell imaging suggests that the probe can be used to study the interaction of small molecules with G-quadruplexes in vivo.
Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ, UK.
Arun
A
Shivalingam
Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ, UK.
M Angeles
MA
Izquierdo
Department of Physics, King's College London, Strand, London WC2R 2LS, UK.
Alix Le
AL
Marois
Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ, UK.
Aurimas
A
Vyšniauskas
Department of Physics, King's College London, Strand, London WC2R 2LS, UK.
Klaus
K
Suhling
Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ, UK.
Marina K
MK
Kuimova
Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ, UK.
Ramon
R
Vilar
D045744:Cell Line, Tumor; D005456:Fluorescent Dyes; D054856:G-Quadruplexes; D006801:Humans; D066298:In Vitro Techniques; D000069416:Intravital Microscopy; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides; D013050:Spectrometry, Fluorescence
D005456:Fluorescent Dyes; D009841:Oligonucleotides