Interaction of antisense DNA with nucleic acids/proteins

Area of Science:

• Biochemistry
• Molecular Biology
• Biophysics

Background:

• Antisense DNA technology utilizes oligonucleotides to modulate gene expression.
• Understanding the interactions of antisense molecules with biological targets is crucial for therapeutic development.
• Various labeling strategies are employed to study molecular interactions.

Purpose of the Study:

• To investigate the interactions of labeled antisense DNAs with nucleic acids and proteins.
• To compare the binding affinities of different antisense DNA modifications to proteins.
• To establish methods for monitoring hybrid formation using spectroscopic techniques.

Main Methods:

• Synthesis of labeled antisense oligonucleotides (ODNs) with fluorescein and nitroxide spin labels.
• Spectroscopic analysis including UV-Vis, fluorescence depolarization, and Electron Spin Resonance (ESR) spectroscopy.
• Monitoring of hybrid formation through changes in fluorescence anisotropy and ESR spectral intensity.

Main Results:

• Fluorescence anisotropy and ESR spectroscopy effectively monitored hybrid formation between antisense DNAs and nucleic acids.
• Phosphorothioate antisense molecules labeled with fluorescein (F-OPT) exhibited a significant increase in fluorescence anisotropy upon interaction with proteins (HSA, HIG, TF).
• Standard ODNs showed a minimal increase in anisotropy when interacting with the same proteins, indicating lower affinity.

Conclusions:

• Phosphorothioate antisense oligonucleotides demonstrate a substantially higher affinity for proteins compared to standard ODNs.
• The developed spectroscopic methods are suitable for characterizing antisense-nucleic acid and antisense-protein interactions.
• These findings have implications for the design and application of antisense-based therapeutics.