Evolution of cell size control is canalized towards adders or sizers by cell cycle structure and selective pressures
- McGill University, Canada
- Stanford University, United States
Abstract
Cell size is controlled to be within a specific range to support physiological function. To control their size, cells use diverse mechanisms ranging from ‘sizers’, in which differences in cell size are compensated for in a single cell division cycle, to ‘adders’, in which a constant amount of cell growth occurs in each cell cycle. This diversity raises the question why a particular cell would implement one rather than another mechanism? To address this question, we performed a series of simulations evolving cell size control networks. The size control mechanism that evolved was influenced by both cell cycle structure and specific selection pressures. Moreover, evolved networks recapitulated known size control properties of naturally occurring networks. If the mechanism is based on a G1 size control and an S/G2/M timer, as found for budding yeast and some human cells, adders likely evolve. But, if the G1 phase is significantly longer than the S/G2/M phase, as is often the case in mammalian cells in vivo, sizers become more likely. Sizers also evolve when the cell cycle structure is inverted so that G1 is a timer, while S/G2/M performs size control, as is the case for the fission yeast S. pombe. For some size control networks, cell size consistently decreases in each cycle until a burst of cell cycle inhibitor drives an extended G1 phase much like the cell division cycle of the green algae Chlamydomonas. That these size control networks evolved such self-organized criticality shows how the evolution of complex systems can drive the emergence of critical processes.
Data availability
This is a theory paper, so there is no experimental data, and all results were generated by the code. The code used is freely available at https://github.com/FelixPG/PhiEvo_SizeControl . Reference to the code has been added in the text.
Article and author information
Author details
Funding
Natural Sciences and Engineering Research Council of Canada (Discovery Grant)
- Paul François
Natural Sciences and Engineering Research Council of Canada (Alexander Graham Bell Canada Graduate Scholarship)
- Felix Proulx-Giraldeau
Fonds de recherche du Québec – Nature et technologies (Doctoral research scholarship)
- Felix Proulx-Giraldeau
National Institutes of Health (NIH R35 GM134858)
- Jan M Skotheim
Chan Zuckerberg Initiative (Biohub Investigator Award)
- Jan M Skotheim
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2022, Proulx-Giraldeau et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Evolution of cell size control is canalized towards adders or sizers by cell cycle structure and selective pressures
eLife 11:e79919.
https://doi.org/10.7554/eLife.79919
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