Lyiba Malik, “CRISPR-Cas 9 Mediated Disruption of the FOSL1a Gene in D. rerio”
Mentor: Ava Udvadia, Biological Sciences
Poster #88

Central nervous system regeneration, specifically regeneration of the optic nerve, is not observed in mammals. This phenomenon is observed in D. rerio due to the differential expression of genes in the retinal ganglion cells that allow injured axons to regenerate and restore vision. The goal of the Udvadia Lab is to determine a program of gene expression that regulates successful optic nerve regeneration in zebrafish. The expression of these genes will be compared to the mammalian counterparts to determine which genes can be induced to replicate axon regeneration that is seen in zebrafish. Of the genes studied in the Udvadia Lab, JUN is the transcription factor most tightly correlated with the regulation of regenerative gene expression. JUN does not act alone. A repertoire of identified genes included the transcription factor FOSL1. FOSL1 is a protein encoding gene that belongs to the basic leucine zipper transcription factor family that can dimerize with proteins from the JUN family to regulate transcription. Previous research in the Udvadia Lab identified the peak expression of FOSL1 at two days post injury in an adult zebrafish. We hypothesize that expression of FOSL1 is necessary with JUN for axon regeneration. The necessity of the FOSL1 gene in optic nerve regeneration will be tested via CRISPR-Cas 9. Using guide RNA and Cas9, the FOSL1 gene will be disrupted in single cell embryos, therefore disrupting its function. We anticipate three possible outcomes: (1) axon regeneration will not occur without the FOSL1 gene; (2) the cell will compensate for the absence of FOSL1 by using another bZIP protein; (3) the embryo may not survive if FOSL1 is necessary for development, in which case mRNA will be injected during development. Combined with additional knockdown studies in the lab, these studies will help to define critical transcription factors for optic nerve regeneration.