A Visual Framework for Classifying Determinants of Cell Size

Cells control their size by coordinating cell cycle progression with volume growth. Size control is typically studied at specific cell cycle transitions that are delayed or accelerated depending on size. This focus is well suited for revealing mechanisms acting at these transitions, but neglects the dynamics in other cell cycle phases, and is therefore inherently limited for studying how the characteristic cell size is determined. We address this limitation through a formalism that intuitively visualizes the characteristic size emerging from integrated cell cycle dynamics of individual cells. Applying this formalism to budding yeast, we describe the contributions of the un-budded (G1) and budded (S-G2-M) phase to size adjustments following environmental or genetic perturbations. We show that although the budded phase can be perturbed with little consequences for G1 dynamics, perturbations in G1 propagate to the budded phase. Our study provides an integrated view on cell size determinants in budding yeast. [Display omitted] •An intuitive visualization framework for cell size control is described•Cell size control in different environments or mutant backgrounds can be compared•Mutual dependencies between size control at different cell cycle phases are described Jonas et al. develop a visual framework to understand the emergence of cell size from the cooperation of multiple size control mechanisms during the cell cycle. With this framework they analyze the size changes after environmental and genetic perturbations and probe the interaction between size control at different cell cycle phases.