In animals, cellularization of a coenocyte is a specialized form of cytokinesis that results in the formation of a polarized epithelium during early embryonic development. It is characterized by coordinated assembly of an actomyosin network, which drives inward membrane invaginations. However, whether coordinated cellularization driven by membrane invagination exists outside animals is not known. To that end, we investigate cellularization in the ichthyosporean Sphaeroforma arctica, a close unicellular relative of animals. We show that the process of cellularization involves coordinated inward plasma membrane invaginations dependent on an actomyosin network and reveal the temporal order of its assembly. This leads to the formation of a polarized layer of cells resembling an epithelium. We show that this stage is associated with tightly regulated transcriptional activation of genes involved in cell adhesion. Hereby we demonstrate the presence of a self-organized, clonally-generated, polarized layer of cells in a unicellular relative of animals.
Sequencing data have been deposited at the following locations :S. arctica genome assembly - BioProject number PRJDB8476S. arctica transcriptomes - PRJEB32922 (ERP115662) on European Nucleotide Archive
Sphaeroforma arctica genome assemblyNCBI BioProject, PRJDB8476.
Dynamics of transcription during the coenocytic cycle of Sphaeroforma arcticaEuropean nucleotide archive, PRJEB32922 (ERP115662).
- Iñaki Ruiz-Trillo
- Atsushi Toyoda
- Hiroshi Suga
- Jon Bråte
- Omaya Dudin
- Omaya Dudin
- Andrej Ondracka
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Mukund Thattai, National Centre for Biological Sciences, India
© 2019, Dudin et al.
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