Abstract
Cell size is determined by a complex interplay between growth and division, involving multiple
cellular pathways. To identify systematically processes affecting size control in G1 in budding
yeast, we imaged and analyzed the cell cycle of millions of individual cells representing 591
mutants implicated in size control. Quantitative metric distinguished mutants affecting the
mechanism of size control from the majority of mutants that have a perturbed size due to indirect
effects modulating cell growth. Overall, we identified 17 negative and dozens positive size control
regulators, with the negative regulators forming a small network centered on elements of mitotic
exit network. Some elements of the translation machinery affected size control with a notable
distinction between the deletions of parts of small and large ribosomal subunit: parts of small
ribosomal subunit tended to regulate size control, while parts of the large subunit affected cell
growth. Analysis of small cells revealed additional size control mechanism that functions in G2/M,
complementing the primary size control in G1. Our study provides new insights about size control
mechanisms in budding yeast.
Collapse