A polymer physics model of the interphase cell nucleus for radiobiological simulations

Area of Science:

• Computational Biology
• Structural Biology
• Radiobiology

Background:

• Advanced imaging and chromosome conformation capture (Hi-C) provide insights into chromatin structure.
• Integrating these insights into radiobiology modeling remains a challenge.
• Existing models struggle with computational costs and accuracy.

Purpose of the Study:

• To develop a polymer physics-based model for simulating 3D chromatin architecture and chromosome aberrations.
• To benchmark the model against experimental radiobiology data.
• To bridge structural biology and radiobiological simulations for improved DNA damage prediction.

Main Methods:

• Utilized polymer physics principles to describe chromosomal and chromatin interactions.
• Employed a multi-stage relaxation strategy to manage computational cost.
• Implemented a distance-dependent DNA end rejoining model and graph theory for aberration simulation.

Main Results:

• Successfully reproduced 3D chromatin architectures (territories, subcompartments, domains, loops).
• Predicted contact maps and probabilities consistent with Hi-C measurements.
• Model predictions for dicentrics, deletions, and total aberrations aligned within 20% of experimental data for gamma rays and alpha particles.

Conclusions:

• The polymer physics model accurately simulates chromatin organization and radiation-induced chromosome aberrations.
• The model shows significant improvement over previous methods, aligning experimental and simulation data.
• This approach holds strong potential for predicting DNA damage and enhancing radiobiological simulations, especially for high-LET radiation effects.