Investigating the Role of Gsx2 In the Development of the Zebrafish Hypothalamus

Caitlyn J. Parker*, R. Madison Riffe*, Samantha L. Phelix*, Sarah N. Peterson*, Zoe Dobler*, Rebecca A. Coltogirone, Alexandra R. Schmidt and Sadie A. Bergeron, Department of Biology, West Virginia University, Morgantown, WV, USA 26505-6057

Field (Broad Category): Biology (Biological & Biochemical Sciences)

Student’s Major: Biology 

Neurodevelopment is controlled by expression of a series of transcription factors encoded by homeobox genes. These proteins bind to specific DNA sequences to direct the growth and migration of neural progenitors into their mature state. In this project, we investigated the role of genomic screen homeobox 2 (gsx2) in the development of the zebrafish hypothalamus. Due to a known gsx2 binding site near the retinal homeobox 3 (rx3) and vesicular glutamate transporter 2a (vglut2a) genes, we hypothesize a loss of gsx2 to result in a change in quantity of progenitors and neurons that express these genes. In order to test this, we used transgenic and mutant lines, including Tg;rx3-GFP;gsx2Δ13a+/- and Tg;vglut2a-RFP; gsx2Δ13a+/-, to examine rx3-expressing neural progenitors and vglut2a-expressing neurons in the larval zebrafish hypothalamus of gsx2 mutants and heterozygotes through confocal microscopy. Preliminary results indicate a significant decrease in the number of mature neurons in the posterior hypothalamus of both mutants and heterozygotes compared to their wild type siblings. Additional Bergeron lab studies investigated a role for gsx1 in the developing hypothalamus, but neuron and progenitor quantities were not significantly different from WT siblings. We looked at the number of neurons and progenitors in the loss of both gsx1 and gsx2, and results are awaiting quantification. In this study we provide novel information on the role of gsx2 in the developing hypothalamus in addition to looking at the effect of the loss of both gsx1 and gsx2. 

Funding: WVU Department of Biology 

Program/mechanism supporting research/creative efforts: Biology 486 capstone