In emerging epithelial tissues, cells undergo dramatic rearrangements to promote tissue shape changes. Dividing cells remain interconnected via transient cytokinetic bridges. Bridges are cleaved during abscission and currently, the consequences of disrupting abscission in developing epithelia are not well understood. We show that the Rab GTPase, Rab25, localizes near cytokinetic midbodies and likely coordinates abscission through endomembrane trafficking in the epithelium of the zebrafish gastrula during epiboly. In maternal-zygotic Rab25a and Rab25b mutant embryos, morphogenic activity tears open persistent apical cytokinetic bridges that failed to undergo timely abscission. Cytokinesis defects result in anisotropic cell morphologies that are associated with a reduction of contractile actomyosin networks. This slows cell rearrangements and alters the viscoelastic responses of the tissue, all of which likely contribute to delayed epiboly. We present a model in which Rab25 trafficking coordinates cytokinetic bridge abscission and cortical actin density, impacting local cell shape changes and tissue-scale forces.
All data generated or analysed during this study are included in the manuscript and supporting files.
- Ashley E E Bruce
- Rodrigo Fernandez-Gonzalez
- Jennifer A Mitchell
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Animal experimentation: This study was performed in strict accordance with the recommendations in the Canadian Council on Animal Care Guidelines on the Care and Use of Fish in Research. All the animals were handled and maintained according to a protocol (Protocol Number: 20012462) approved by the Biological Sciences Local Animal Care Committee at the University of Toronto.
- Michel Bagnat, Duke University, United States
© 2021, Willoughby et al.
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