Transcriptional Regulation of Zebrafish Enteric Nervous System Development

Author: Huang, Yuanyun (Rose)

Year: 2027

Degree: Dissertation (Ph.D.)

Advisor: Bronner, Marianne E.

Committee Members: Rothenberg, Ellen V.; Prober, David A.; Gradinaru, Viviana; Bronner, Marianne E.

Option: Biochemistry and Molecular Biophysics

DOI: 10.7907/jh70-1861

Abstract

The vertebrate enteric nervous system (ENS) is mainly derived from vagal neural crest cells, which enter the foregut as progenitors that migrate from rostral to caudal to populate the entire length of the gut. Here, we show that transcription factors sox11a and sox11b, zebrafish orthologs of the human SOX11 gene, are highly expressed in neural crest cells transitioning from progenitors to differentiating neuronal subtypes. Accordingly, CRISPR-Cas9 depletion shows that loss of sox11 paralogs reduces the number of neurons that express the inhibitory motor neuron marker adcyap1b without affecting cell proliferation or death. Transcription factor footprinting analysis of open chromatin regions identified by ATAC-seq reveals Sox11 binding sites in the adcyap1b enhancer. Furthermore, mutational analysis shows these binding sites are required for mediating enhancer-driven reporter expression. Taken together, our results demonstrate an important and previously unrecognized role for sox11a and sox11b in neuronal subtype specification in the developing zebrafish ENS.

To further probe neuronal differentiation in the developing ENS, we examine its spatial structure using multiplex hybridization chain reaction in situ hybridization. Developing a pipeline that covers both the sample preparation and downstream imaging analysis, we are able to capture the temporal- and spatial- specific expression pattern of neuronal clusters in zebrafish ENS at multiple developmental stages. The results reveal spatial heterogeneity in neuronal subtypes and changes as a function of stage in neuronal composition.

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