A Genetic Screen for Tribbles Suppressors Identifies the E3 Ubiquitin Ligase Neuralized as a Novel Target

In this dissertation, I used the Drosophila wing as a model tissue for a genetic screen to identify novel targets of Tribbles. Drosophila Tribbles is the founding member of a family of pseudokinases conserved between metazoans. Tribbles family proteins have roles in the cell cycle, insulin signaling, tissue growth and early development, and have been associated with a myriad of human diseases. In the wing, expression of tribbles by the engrailed-GAL4 driver generates a distinct visual phenotype; larger cells in the posterior of the wing and overall smaller tissue size. Co-misexpression of the known targets of Tribbles slbo (Slow Border Cells) and string suppresses the Tribbles wing phenotype. We used this observation as a tool to screen for additional Tribbles targets and from our screen we identified three E3 Ubiquitin ligases as novel interactors; Neuralized, Mindbomb1 and Parkin. Of the targets identified from the screen, we focused on Neuralized. We found that Tribbles physically bound to Neuralized in a yeast two hybrid assay and in vivo, Tribbles co misexpression in an ovarian model epithelium, the follicle cells, stabilized a tagged version of Neuralized. Neuralized has known roles in Notch signaling, and so we hypothesized that Tribbles promotes Notch signaling in the follicle cells and consistent with this, we found that both Tribbles and Neuralized turn on expression of Eyes Absent, a marker of stretch cell flattening activated by Neuralized-mediated Notch signaling.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Molecular Biology and Biochemistry (UMKC)

Grantor dc:publisher

University of Missouri -- Kansas City

Year dc:date.issued

2017

Author dc:creator

• Shipman, Anna Lynn

Advisor dc:contributor.advisor

• Dobens, Leonard L.

Language dc:language.iso

en_US

Handle dc:identifier.uri

https://hdl.handle.net/10355/66913

OAI identifier oai:identifier

oai:mospace.umsystem.edu:10355/66913