Feedback regulation in the lactose operon: a mathematical modeling study and comparison with experimental data

Area of Science:

• Molecular Biology
• Systems Biology
• Biophysics

Background:

• The lac operon in Escherichia coli controls lactose metabolism.
• Understanding its regulatory dynamics is crucial for molecular biology.
• Previous models may not fully capture the complex interactions involved.

Purpose of the Study:

• To develop a comprehensive mathematical model for lac operon induction regulation.
• To accurately simulate the dynamics of key molecular components.
• To investigate potential bistable behaviors in the system.

Main Methods:

• Developed a model with five nonlinear differential delay equations.
• Incorporated dynamics of permease, internal lactose, beta-galactosidase, allolactose, lac repressor, and mRNA.
• Estimated model parameters and validated against experimental data.

Main Results:

• The model demonstrated excellent agreement with experimental beta-galactosidase activity data.
• Simulations matched data from static and periodically perturbed conditions.
• Identified a physiological regime exhibiting bistable steady-state behavior.

Conclusions:

• The mathematical model provides a robust framework for studying lac operon regulation.
• Bistable dynamics are possible within realistic physiological parameters.
• The model offers insights into gene regulatory network stability and behavior.