Cell size control driven by the circadian clock and environment in cyanobacteria.
Proc Natl Acad Sci U S A
Proceedings of the National Academy of Sciences
MetadataShow full item record
Martins, B. M., Tooke, A. K., Thomas, P., & Locke, J. (2018). Cell size control driven by the circadian clock and environment in cyanobacteria.. Proc Natl Acad Sci U S A, 115 (48), E11415-E11424. https://doi.org/10.1073/pnas.1811309115
How cells maintain their size has been extensively studied under constant conditions. In the wild, however, cells rarely experience constant environments. Here, we examine how the 24-h circadian clock and environmental cycles modulate cell size control and division timings in the cyanobacterium Synechococcus elongatus using single-cell time-lapse microscopy. Under constant light, wild-type cells follow an apparent sizer-like principle. Closer inspection reveals that the clock generates two subpopulations, with cells born in the subjective day following different division rules from cells born in subjective night. A stochastic model explains how this behavior emerges from the interaction of cell size control with the clock. We demonstrate that the clock continuously modulates the probability of cell division throughout day and night, rather than solely applying an on-off gate to division, as previously proposed. Iterating between modeling and experiments, we go on to identify an effective coupling of the division rate to time of day through the combined effects of the environment and the clock on cell division. Under naturally graded light-dark cycles, this coupling narrows the time window of cell divisions and shifts divisions away from when light levels are low and cell growth is reduced. Our analysis allows us to disentangle, and predict the effects of, the complex interactions between the environment, clock, and cell size control.
Synechococcus, Environment, Ecosystem, Cell Division, Cell Size, Light, Models, Biological, Circadian Clocks
Is supplemented by: https://doi.org/10.17863/CAM.31834
European Research Council (338060)
Biotechnology and Biological Sciences Research Council (BB/L014130/1)
Gatsby Charitable Foundation (unknown)
Human Frontier Science Program (HFSP) (CDA-/2012)
External DOI: https://doi.org/10.1073/pnas.1811309115
This record's URL: https://www.repository.cam.ac.uk/handle/1810/286522
Attribution 4.0 International
Licence URL: https://creativecommons.org/licenses/by/4.0/