Modelling how plant cell-cycle progression leads to cell size regulation

Area of Science:

• Plant cell biology
• Mathematical modeling
• Cell cycle regulation

Background:

• Cell populations maintain consistent size despite asymmetrical division, indicating a size control mechanism.
• While size control is understood in many organisms, its function in plants remains unclear.

Purpose of the Study:

• To develop a mathematical model of the plant cell cycle to understand size control mechanisms.
• To investigate how cell-cycle progression depends on cell size in plants.
• To determine how plant cells achieve size homeostasis over multiple generations.

Main Methods:

• Developed a mathematical model of key plant cell-cycle interactions.
• Simulated cell-cycle progression in growing cells under different size control hypotheses.
• Modeled cell populations undergoing multiple divisions to assess long-term size homeostasis.

Main Results:

• Model simulations revealed limit-cycle solutions and biological switches at G1/S and G2/M transitions.
• Two mechanisms—differential protein expression and equal inhibitor inheritance—were shown to promote cell-size control.
• Integrating size control at both G1/S and G2/M transitions was essential for long-term size homeostasis.

Conclusions:

• Plant cells utilize cell-cycle network features to link progression to cell size.
• Differential protein expression and equal inhibitor inheritance contribute to cell-size control.
• Combined size control at G1/S and G2/M is crucial for maintaining plant cell population size homeostasis across generations.