| dc.description.abstract | To better understand how Insm1, Neurod1 and Pax6 contribute to the formation and function of pancreatic endocrine cells I performed comparative immunohistochemical, transcriptomic, functional enrichment, and RNA splicing analyses using gene knock-out mice. Quantitative immunohistochemical analysis confirmed that elimination of each of these three factors variably impaired the proliferation, survival, and differentiation of endocrine cells. Transcriptomic analysis revealed that many genes were commonly affected, although each factor also had unique effects on the transcriptome. Functional enrichment analysis of the affected genes revealed that downregulated genes are commonly involved in mRNA metabolism, chromatin organization, secretion, and cell cycle regulation, and upregulated genes are associated with protein degradation, autophagy, and apoptotic process. Interestingly, elimination of Insm1, Neurod1 and Pax6 impaired expression of many RNA binding proteins, thereby altering RNA splicing events, including for Syt14 and Snap25, two genes required for insulin section. All three factors are necessary for normal splicing of Syt14, and both Insm1 and Pax6 are necessary for the processing of Snap25. Finally, I found that several understudied zinc finger proteins exhibit endocrine-specific expression patterns and are regulated by each of the three transcription factors described here. To better understand the function of these zinc finger proteins I generated knockout animal models, including Zfp800 and Jazf1, and found that each plays a role in growth and development. Collectively, these data provide a deeper understanding of how Insm1, Neurod1, and Pax6 contribute to the behavior of the pancreatic endocrine cell regulatory network and are essential for the formation of functional endocrine cells. | |
