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Single-Molecule Fluorescence Visualization of DNA Polymerase Dynamics at G-Quadruplexes
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The interactions between a small molecule and G-quadruplexes are visualized by fluorescence lifetime imaging
Arun Shivalingam1, M Angeles Izquierdo1, Alix Le Marois2
1Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ, UK.
Nature Communications
|September 10, 2015
Summary
Researchers developed a novel fluorescent probe to visualize G-quadruplexes in living cells. This probe offers a new tool for studying these important nucleic acid structures and their interactions in real-time.
Area of Science:
- Molecular Biology
- Biophysics
- Chemical Biology
Background:
- Guanine-rich oligonucleotides form G-quadruplexes, non-canonical DNA structures with crucial in vivo roles.
- Existing methods lack small-molecule optical probes for imaging G-quadruplexes in live cells.
Purpose of the Study:
- To design and develop a novel small fluorescent molecule as an optical probe for G-quadruplexes.
- To validate the probe's ability to image G-quadruplexes in live cells and study molecular interactions.
Main Methods:
- Synthesis and characterization of a new fluorescent molecule.
- In vitro fluorescence lifetime measurements with various nucleic acid topologies (G-quadruplex, double-stranded, single-stranded DNA/RNA).
- Cellular uptake, cytotoxicity, and localization studies.
- Live-cell imaging using fluorescence lifetime imaging microscopy (FLIM).
Main Results:
- The fluorescent probe exhibits distinct fluorescence lifetime changes upon binding to G-quadruplexes compared to other nucleic acid structures.
- The probe is cell-permeable, exhibits low cytotoxicity, and localizes to the cell nucleus.
- Live-cell imaging demonstrates the probe's potential for studying G-quadruplexes and their interactions in vivo.
Conclusions:
- A novel fluorescent probe has been successfully developed for G-quadruplex detection.
- The probe enables G-quadruplex imaging in live cells, opening avenues for studying their biological functions and drug interactions.
