CYK-4 functions independently of its centralspindlin partner ZEN-4 to cellularize oocytes in germline syncytia
Throughout metazoans, germ cells undergo incomplete cytokinesis to form syncytia connected by intercellular bridges. Gamete formation ultimately requires bridge closure, yet how bridges are reactivated to close is not known. The most conserved bridge component is centralspindlin, a complex of the Rho family GTPase-activating protein (GAP) CYK-4/MgcRacGAP and the microtubule motor ZEN-4/kinesin-6. Here, we show that oocyte production by the syncytial C. elegans germline requires CYK-4 but not ZEN-4, which contrasts with cytokinesis, where both are essential. Longitudinal imaging after conditional inactivation revealed that CYK-4 activity is important for oocyte cellularization, but not for the cytokinesis-like events that generate syncytial compartments. CYK-4's lipid-binding C1 domain and the GTPase-binding interface of its GAP domain were both required to target CYK-4 to intercellular bridges and to cellularize oocytes. These results suggest that the conserved C1-GAP region of CYK-4 constitutes a targeting module required for closure of intercellular bridges in germline syncytia.
All data generated or analyzed during this study are included in the manuscript and supporting files.
Article and author information
National Institutes of Health (T32 CA067754)
- J Sebastian Gomez-Cavazos
National Science Foundation (PHY-14113130)
- Alex Groisman
Ludwig Institute for Cancer Research
- Arshad Desai
- Karen Oegema
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Mohan K Balasubramanian, University of Warwick, United Kingdom
- Received: March 23, 2018
- Accepted: July 9, 2018
- Accepted Manuscript published: July 10, 2018 (version 1)
- Version of Record published: July 23, 2018 (version 2)
This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
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