THE ROLE OF SIAH E3 UBIQUITIN LIGASE DURING RETINAL DEVELOPMENT IN ZEBRAFISH

Eye development within zebrafish is a complex process that involves the differentiation and proliferation of the cells that comprise the highly specified retina. Failure of this process due to mutations in key factors can result in congenital retinal diseases. Currently, there is little-to no treatment to prevent vision loss among humans with congenital retinal diseases. To better understand the physiological changes associated with congenital blinding disorders, my project aims to investigate the role of post-translational modifications during retinal development. In particular, I am interested in the mechanism of adding polyubiquitin chains to specific molecules so they can be targeted for proteasomal degradation. Siah, an E3 ubiquitin ligase, previously shown to be involved in fruit fly eye development and more recently zebrafish optic fissure closure is the primary focus of my project. As an E3 enzyme, Siah directly selects targets for polyubiquitination. Previous work in the lab identified a protein CDHR1a as a target of Siah. CDHR1a is a cadherin-related family member known to be necessary for photoreceptor disk maturation. I hypothesize that Siah is directly responsible for modulating the stability of CDHR1a through proteasomal degradation during photoreceptor disk maturation. The goal of my project is to conduct the beginning experiments that will help determine if Siah does bind to CDHR1a. By testing whether they are colocalized together with whole-mount in situ hybridization, 2-color fluorescence whole-mount in situ hybridization, and immunohistochemistry, the results suggest that CDHR1a is being regulated by Siah throughout eye development