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

• Published in: PLoS computational biology 2023-10, Vol.19 (10), p.e1011503-e1011503
• Main Authors: Williamson, Daniel, Tasker-Brown, William, Murray, James A. H, Jones, Angharad R, Band, Leah R
• Format: Article
• Language: English
• Subjects: Analysis; Cell cycle; Cell division; Cell size; Cyclin-dependent kinases; Daughters; Embedding; Heredity; Homeostasis; Inhibitors; Kinases; Mathematical models; Plant cells and tissues; Populations; Proteins; Simulation methods; Yeast
• ISSN: 1553-7358; 1553-734X; 1553-7358
• DOI: 10.1371/journal.pcbi.1011503

Here, we present a mathematical model of the key interactions in the plant cell cycle. Model simulations reveal that the network of interactions exhibits limit-cycle solutions, with biological switches underpinning both the G1/S and G2/M cell-cycle transitions. Embedding this network model within growing cells, we test hypotheses as to how cell-cycle progression can depend on cell size. We investigate two different mechanisms at both the G1/S and G2/M transitions: (i) differential expression of cell-cycle activator and inhibitor proteins (with synthesis of inhibitor proteins being independent of cell size), and (ii) equal inheritance of inhibitor proteins after cell division. The model demonstrates that both these mechanisms can lead to larger daughter cells progressing through the cell cycle more rapidly, and can thus contribute to cell-size control. To test how these features enable size homeostasis over multiple generations, we then simulated these mechanisms in a cell-population model with multiple rounds of cell division. These simulations suggested that integration of size-control mechanisms at both G1/S and G2/M provides long-term cell-size homeostasis.