Combined effect of cell geometry and polarity domains determines the orientation of unequal division
Cell division orientation is thought to result from a competition between cell geometry and polarity domains controlling the position of the mitotic spindle during mitosis. Depending on the level of cell shape anisotropy or the strength of the polarity domain, one dominates the other and determines the orientation of the spindle. Whether and how such competition is also at work to determine unequal cell division (UCD), producing daughter cells of different size, remains unclear. Here, we show that cell geometry and polarity domains cooperate, rather than compete, in positioning the cleavage plane during UCDs in early ascidian embryos. We found that the UCDs and their orientation at the ascidian third cleavage rely on the spindle tilting in an anisotropic cell shape, and cortical polarity domains exerting different effects on spindle astral microtubules. By systematically varying mitotic cell shape, we could modulate the effect of attractive and repulsive polarity domains and consequently generate predicted daughter cell size asymmetries and position. We therefore propose that the spindle position during UCD is set by the combined activities of cell geometry and polarity domains, where cell geometry modulates the effect of cortical polarity domain(s).
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ANR (ANR-17-CE 13-0028))
- Alex McDougall
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Danelle Devenport, Princeton University, United States
- Preprint posted: May 4, 2021 (view preprint)
- Received: November 17, 2021
- Accepted: December 2, 2021
- Accepted Manuscript published: December 10, 2021 (version 1)
- Version of Record published: December 21, 2021 (version 2)
© 2021, Godard 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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