Aurora A depletion reveals centrosome-independent polarization mechanism in C. elegans
- Swiss Federal Institute of Technology, Switzerland
- University of Geneva, Switzerland
- Technische Universität Dresden, Germany
Abstract
How living systems break symmetry in an organized manner is a fundamental question in biology. In wild type Caenorhabditis elegans zygotes, symmetry breaking during anterior-posterior axis specification is guided by centrosomes, resulting in anterior-directed cortical flows and a single posterior PAR-2 domain. We uncover that C. elegans zygotes depleted of the Aurora A kinase AIR-1 or lacking centrosomes entirely usually establish two posterior PAR-2 domains, one at each pole. We demonstrate that AIR-1 prevents symmetry breaking early in the cell cycle, whereas centrosomal AIR-1 instructs polarity initiation thereafter. Using triangular microfabricated chambers, we establish that bipolarity of air-1(RNAi) embryos occurs effectively in a cell-shape and curvature-dependent manner. Furthermore, we develop an integrated physical description of symmetry breaking, wherein local PAR-2-dependent weakening of the actin cortex, together with mutual inhibition of anterior and posterior PAR proteins, provides a mechanism for spontaneous symmetry breaking without centrosomes.
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Funding
European Molecular Biology Organization (ALTF 81-2017)
- Kerstin Klinkert
European Molecular Biology Organization (ALTF 1426-2016)
- Marie Pierron
Fondation Bettencourt Schueller
- Nicolas Levernier
Swiss National Science Foundation (31003A_155942)
- Pierre Gönczy
Swiss National Science Foundation (205321_175996)
- Karsten Kruse
H2020 European Research Council (281903)
- Stephan W Grill
H2020 European Research Council (742712)
- Stephan W Grill
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2019, Klinkert 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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