MSc Exit Seminar – Emily Chien (Godt and Tepass Lab)

Abstract

The FERM domain protein Okapi (Oka) is important for normal Drosophila oogenesis. I found that Oka is required in the follicle stem cell (FSC) lineage to prevent an overgrowth of FSCs. To determine how Oka regulates FSCs, I analyzed interactions between oka and Hippo pathway genes, as they have similar mutant phenotypes. Hippo is known to limit nuclear translocation and activity of Yorkie, thereby suppressing cell proliferation. I found a higher proportion of FSCs with nuclear Yorkie in oka mutants than in wild-type. Reduction of Yorkie or Hippo overexpression partially rescued the FSC overgrowth in oka mutant ovaries. Strikingly, I found that oka mutant FSCs were lost when forced to compete with wild-type FSCs, whereas hippo mutant FSCs are known to be hyper-competitive. My findings indicate that Oka regulates the number of FSCs through the Hippo pathway and is required to make FSCs competitive through an unknown mechanism.