Analysis of Karst Mutant Clones In Drosophila

Open Access
Evangelista, Meagan Elizabeth
Area of Honors:
Biochemistry and Molecular Biology
Bachelor of Science
Document Type:
Thesis Supervisors:
  • Graham Hugh Thomas, Thesis Supervisor
  • David Scott Gilmour, Honors Advisor
  • Scott Brian Selleck, Faculty Reader
  • mitotic clones
  • karst
  • imaginal discs
  • SAC
The development of apical-basal polarity is important for epithelial cells and is vital for cell function. The disruption of such polarity needs to be understood so as to fully comprehend the protein-protein interactions that occur to maintain this polarity. One key protein in the development of the apical domain in Drosophila is spectrin, specifically βHeavy spectrin (βH). In normal cells, βH interacts with an apical transmembrane protein Crumbs to help regulate the apical membrane. Several other proteins also associate with Crumbs to form the subapical complex (SAC) that maintains apical membrane polarity and area. A mutation in any of these proteins has the potential to disrupt apical membrane polarity, area and function. The experiments presented in this thesis seek to determine the effects on Crumbs as well as other proteins of the SAC in the absence of βH function. I have investigated the karst1 mutation, which produces a truncated protein that we hypothesize may alter the levels and/or distribution of Crumbs and other SAC proteins. My strategy was to generate loss of function karst mutant clones in wild type tissues and to stain for SAC components. The results from this approach indicated that it is harder than anticipated to create karst mitotic clones in third instar larval imaginal discs. Thus, an alternative set of experiments were done to see the effects of the loss of βH using karst RNAi. The results indicate that loss of βH has an effect on the level of MAP kinase activation. Specifically, loss of βH increases dp-ERK staining levels in third instar imaginal wing discs. The full extent of these effects have not been fully determined, but these experiments should be able to be completed in the near future.