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Cell size control driven by the circadian clock and environment in cyanobacteria

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 Syne...

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Autores principales: Martins, Bruno M. C., Tooke, Amy K., Thomas, Philipp, Locke, James C. W.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: National Academy of Sciences 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6275512/
https://www.ncbi.nlm.nih.gov/pubmed/30409801
http://dx.doi.org/10.1073/pnas.1811309115
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author Martins, Bruno M. C.
Tooke, Amy K.
Thomas, Philipp
Locke, James C. W.
author_facet Martins, Bruno M. C.
Tooke, Amy K.
Thomas, Philipp
Locke, James C. W.
author_sort Martins, Bruno M. C.
collection PubMed
description 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.
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spelling pubmed-62755122018-12-05 Cell size control driven by the circadian clock and environment in cyanobacteria Martins, Bruno M. C. Tooke, Amy K. Thomas, Philipp Locke, James C. W. Proc Natl Acad Sci U S A PNAS Plus 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. National Academy of Sciences 2018-11-27 2018-11-08 /pmc/articles/PMC6275512/ /pubmed/30409801 http://dx.doi.org/10.1073/pnas.1811309115 Text en Copyright © 2018 the Author(s). Published by PNAS. http://creativecommons.org/licenses/by/4.0/ This open access article is distributed under Creative Commons Attribution License 4.0 (CC BY) (http://creativecommons.org/licenses/by/4.0/) .
spellingShingle PNAS Plus
Martins, Bruno M. C.
Tooke, Amy K.
Thomas, Philipp
Locke, James C. W.
Cell size control driven by the circadian clock and environment in cyanobacteria
title Cell size control driven by the circadian clock and environment in cyanobacteria
title_full Cell size control driven by the circadian clock and environment in cyanobacteria
title_fullStr Cell size control driven by the circadian clock and environment in cyanobacteria
title_full_unstemmed Cell size control driven by the circadian clock and environment in cyanobacteria
title_short Cell size control driven by the circadian clock and environment in cyanobacteria
title_sort cell size control driven by the circadian clock and environment in cyanobacteria
topic PNAS Plus
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6275512/
https://www.ncbi.nlm.nih.gov/pubmed/30409801
http://dx.doi.org/10.1073/pnas.1811309115
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