During animal development, epithelial tissues undergo morphogenesis in order to build tissues, organs and body structure. A key driving force in epithelial morphogenesis is cell rearrangement, which results from the remodelling of cell-cell contacts. In epithelia, cell-cell contacts are connected via vertices, where 3 or more cells meet. It is unknown whether cell vertices play an active role in regulating cell rearrangement, however recent work from a number of model systems has suggested that cell vertices are important sites for sensing and regulating tissue tension and providing geometric cues for morphogenetic cell behaviours. I have used the Drosophila model system to investigate the behaviour and role of vertices in epithelial morphogenesis, using as an entry point a newly discovered marker of epithelial vertices, the Immunoglobulin-superfamily domain protein Sidekick. I have characterised the localisation of Sidekick tagged with YFP in a number of Drosophila epithelial tissues and found that in most epithelial tissues, Sidekick-YFP localises to vertices at the level of adherens junctions. Using super-resolution microscopy, I investigated the localisation of Sidekick-YFP during germband extension in the early embryo and found that Sidekick-YFP forms string-like structures at cell vertices at the level of adherens junctions, indicating that large multi-protein complexes containing Sidekick define a novel cortical domain in Drosophila epithelia. Through characterisation of a null allele of sidekick in Drosophila early embryos using both manual and automated large-scale quantitative analysis, I have found that tissue geometry, cell adhesion and morphogenetic cell behaviours are abnormal in the absence of sidekick. Together, my work shows that Sidekick at apical vertices is a novel regulator of epithelial morphogenesis.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:744702 |
| Date | January 2018 |
| Creators | Finegan, Tara May |
| Contributors | Sanson, Benedicte |
| Publisher | University of Cambridge |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://www.repository.cam.ac.uk/handle/1810/274873 |
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