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Deborah Eastman

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Taste buds play a functional role in the sustenance of life by detecting safe and energy rich food sources. The development of these structures progresses through events of specification, determination, patterning, and differentiation within the oropharyngeal endoderm (OPE) in a highly coordinated fashion. Previous work in mouse and zebrafish model systems implicates the Notch signaling pathway as being involved in the coordination of taste bud development. Further evidence for a contact mediated cell signaling system is found in the model system, Ambystoma mexicanum. A. mexicanum, or axolotl, is an ideal model organism for the study of taste bud patterning and differentiation, yet the question of Notch’s role remains unexplored. The focus of my honors thesis was to analyze expression of genes during critical stages of taste bud development in the OPE in a qualitative and quantitative manner. This included a genomics-level approach to identify genes associated with specific stages of taste bud development and a specific analysis of the Notch pathway during these same stages. Reverse transcriptase-qPCR analysis of several Notch genes indicated differential expression during critical stages of taste cell specification, patterning, and differentiation. Visualization of taste epithelium via immunofluorescence of calretinin antibodies specified the presence and distribution of taste cells in the taste epithelium and will serve as a control for functional studies of Notch signaling during taste bud development. Final RNASeq transcriptome analysis revealed differential expression of 131 genes between stages prior to and following taste bud differentiation. These collective results support a role for the Notch pathway during taste bud development, and provide important insights into other genes and pathways that may also be involved.



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