Fluorescent probe for visualizing guanine-quadruplex DNA by fluorescence lifetime imaging microscopy

Area of Science:

• Biochemistry
• Molecular Biology
• Genetics

Background:

• Guanine-quadruplex (G4) structures are crucial for telomere stability and gene regulation.
• The presence and function of G4 structures in living cells remain under investigation.
• Developing tools to detect and visualize G4 structures in vivo is essential.

Purpose of the Study:

• To characterize a novel fluorescent probe, o-BMVC, for differentiating G4 structures from duplex DNA.
• To demonstrate the utility of o-BMVC for detecting and visualizing G4 structures in vitro and in living cells.

Main Methods:

• Characterization of the fluorescent probe o-BMVC, including its binding affinity, fluorescence intensity, and decay time with G4 and duplex DNA.
• In vitro detection of G4 structures using fluorescence decay time analysis.
• Visualization and localization of G4 structures in living cells using fluorescence lifetime imaging microscopy (FLIM).

Main Results:

• o-BMVC exhibits distinct fluorescence decay times (∼2.8 ns for G4, ∼1.2 ns for duplex DNA).
• The probe successfully detected G4 structures at a low ratio (1 G4 per 1000 duplexes) in vitro.
• FLIM demonstrated the ability to visualize and map G4 structures within living cells.

Conclusions:

• o-BMVC is a sensitive and specific fluorescent probe for G4 DNA structures.
• The study provides a robust methodology for visualizing G4 structures in living cells, supporting their biological relevance.
• This work advances the understanding of G4 structure dynamics and functions in cellular environments.