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MSc Exit Seminar – Stefan Vujadinovic – Monday, September 25th, 2017
September 25 @ 11:10 am - 11:30 am
MSc Exit Seminar
Monday, September 25, 2017 at 11:10 am, Ramsay Wright Building, Room 432
Stefan Vujadinovic (Tepass Lab)
The Okapi (Oka) FERM Domain Protein Regulates Somatic Stem Cell Numbers and Cell Intercalation during Drosophila Oogenesis
Okapi (Oka) is a Drosophila melanogaster FERM domain protein that is essential for oogenesis. oka (CG34347) null mutants are viable but display multiple defects during oogenesis. Mutant ovaries showed greatly enlarged and multilayered interfollicular stalks, compromised follicular epithelia, and germline disorganization, leading to reduced female fertility. I generated both endogenously and exogenously GFP-tagged Oka protein to examine the distribution of Oka.
Oka was present is all somatic cells of the ovary and localized to adherens junctions (AJs) in the germarium and follicles, including the cap cells, follicular epithelium, intercalating cells that form the interfollicular stalk, and in the migrating border cell cluster and centripetal cells. I also found that oka mutant ovaries contain an increased number of follicle stem cells, a defect that could explain the increased somatic cell numbers observed, and is reminiscent of the phenotypes of several overactive signalling pathways such as Hippo and Hedgehog. Examination of a series of five oka alleles that display different phenotypic strength suggest that interfollicular stalk formation is more sensitive to the reduction in Oka function than other observed defects. Together, my findings suggest that Oka is a component of AJs that negatively regulates follicle stem cell numbers and is required for the intercalation of interfollicular stalk cells.