Tag: Julia Ganz

Presenter: Charlotte Taylor

Mentors: Judith Eisen and Julia Ganz, Biology

Poster: 62

Major: Biochemistry 

The enteric nervous system (ENS) provides intrinsic intestinal innervation and modulates intestinal function. The ENS forms a complex network of neuronal and glial subtypes. ENS progenitors that give rise to this network express different marker genes, e.g. phox2b, sox10, and ret. Using the zebrafish model, we investigated whether expression of these markers defines distinct ENS progenitor subpopulations. Gene expression revealed subpopulations, the most prominent of which are characterized by the following combinations: phox2b; phox2b/ret; phox2b/sox10; phox2b/ret/sox10. We will now determine whether these distinct progenitors have functional significance for ENS development. We will use the Cre/loxP lineage tracing system to track progeny of distinct progenitor subpopulations and determine if they give rise to different ENS cell types. Using BAC-recombineering, we will generate BAC- constructs that drive Cre recombinase expression under enteric progenitor specific promoters (e.g. ret). To test if BAC enteric progenitor promoter sequences drive expression faithfully, we are generating BAC-constructs that drive expression of green fluorescent proteins (GFP). We are currently analyzing ENS GFP expression of a modified ret BAC. After generating Cre-constructs, we will inject them into a reporter line and identify progeny of labeled progenitors at different times during ENS development. Our results will provide a comprehensive lineage analysis of ENS precursors in vivo and thus offer new insights into ENS development and the potential of individual ENS precursors.

Presenter: Parham Diba

Mentors: Julia Ganz and Judith Eisen, Biology

Poster: 18

Major: Human Physiology 

The enteric nervous system (ENS) is the largest part of the peripheral nervous system, containing about 400–600 million neurons in humans. It comprises a complex network of neurons and glia and controls intestinal functions, such as motility. Hirschsprung disease (HSCR) is a multifactorial congenital disease in which distal intestine is uninnervated and immotile. A variety of signaling pathways, including the endothelin signaling pathway, regulate ENS development during embryonic stages. In mouse, Endothelin3 and endothelin receptor type B regulate ENS development and mutations in these genes are found in some HSCR patients. However, there are still open questions about how the endothelin pathway is involved in ENS development, such as how it affects progenitor migration and neuronal subtype differentiation. To test the role of the endothelin pathway in ENS development, we are generating zebrafish mutants in components of the endothelin pathway using CRISPR/Cas9 genome editing technology. We are currently creating zebrafish mutants in several different endothelin ligands and endothelin converting enzyme 1 and we have generated a mutant in the endothelin receptor gene ednrb1b. We will then analyze the phenotypes of these mutants to learn how ENS progenitor migration and differentiation are affected. Our strategy will enable us to explore the role of endothelin signaling pathway genes in ENS development and to determine if mutations in these genes lead to an HSCR-like phenotype.