Stochastic epigenetic dynamics of gene switching

Area of Science:

• Molecular Biology
• Systems Biology
• Biophysics

Background:

• Histone modifications regulate eukaryotic gene activity.
• Transcription factors (TFs) bind DNA, influencing histone states.
• Feedback loops between TFs and histone states are crucial for cell fate determination.

Purpose of the Study:

• To theoretically analyze dynamical feedback regulations in epigenetic gene switching.
• To investigate the interplay between TF binding and histone state dynamics.
• To understand the mechanisms underlying cell fate decisions in gene networks.

Main Methods:

• Extended the Doi-Peliti operator formalism for reaction kinetics.
• Applied spin-1 and spin-1/2 coherent-state representations for stochastic reactions.
• Analyzed coupled molecular processes involving histones and TFs.

Main Results:

• Demonstrated that slow histone dynamics can cause hysteresis in gene switching, even with rapid TF binding/unbinding.
• Identified a circular probability flux in the gene state distribution landscape.
• Showed that in self-regulating circuits, histone modification can precede TF amount changes, contrary to prior belief.

Conclusions:

• The study elucidates a nonlinear, nonadiabatic mechanism for epigenetic cell fate decision-making.
• Highlights the importance of timescale differences in molecular processes.
• Provides insights into the dynamic interplay governing gene regulation and cell differentiation.