Deciphering DNA replication dynamics in eukaryotic cell populations in relation with their averaged chromatin...

Area of Science:

• Molecular Biology
• Biophysics
• Genetics

Background:

• Eukaryotic DNA replication initiation exhibits significant spatiotemporal uncertainty in cell populations.
• Understanding the regulatory mechanisms governing replication dynamics is crucial for cell cycle control and genome stability.

Purpose of the Study:

• To develop a non-local model for DNA replication that incorporates initiation uncertainty in eukaryotes.
• To derive an analytical expression for replication initiation rate and predict key replication dynamics.

Main Methods:

• Modeling replication initiation as a two-state system with all transition configurations considered.
• Incorporating the fractal dimension of chromatin into the model.
• Deriving an analytical expression for the rate of replication initiation.

Main Results:

• The model analytically predicts temporal profiles of initiation rate, replication fork density, and fraction of replicated DNA.
• Quantitative agreement was achieved with experimental data from both yeast (S. cerevisiae) and human cells.
• The model provides a quantitative estimate of initiation site redundancy.

Conclusions:

• Eukaryotic DNA replication dynamics are largely a collective phenomenon emerging from stochastic initiation at replication origins.
• The proposed model accurately describes replication initiation without free parameters, validating its predictive power.
• This work offers new insights into the regulation of eukaryotic DNA replication programs.