Requirement and Function of Hippo Pathway Signaling in the Mammalian Gastrointestinal Tract: A Dissertation
AuthorsCotton, Jennifer L.
Faculty AdvisorJunhao Mao, Ph.D.
Academic ProgramCancer Biology
UMass Chan AffiliationsMolecular, Cell and Cancer Biology Department
Document TypeDoctoral Dissertation
Neoplastic Cell Transformation
Mesenchymal Stromal Cells
Signal Transducing Adaptor Proteins
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AbstractIn cancer, aberrant activation of developmental signaling pathways such as the Hippo Pathway has been shown to drive proliferation and invasion of cancer cells. Therefore, understanding the normal function of the Hippo Pathway during embryonic development can provide critical insight into how aberrant activity contributes to tumorigenesis. This dissertation explores the role of the Hippo Pathway members YAP and TAZ in gastrointestinal (GI) development and tumorigenesis. I use mouse genetics to systematically dissect the roles of YAP/TAZ in the endoderm-derived gastrointestinal epithelia and mesoderm-derived gastrointestinal mesenchyme during mammalian development. In the GI epithelium, I demonstrate that YAP/TAZ are dispensable for development and homeostasis. However, YAP/TAZ are required for Wnt pathway-driven tumorigenesis. I find that YAP/TAZ are direct transcriptional targets of Wnt/TCF4 signaling. In the GI mesenchyme, I describe a previously unknown requirement for YAP/TAZ activity during mammalian GI development. YAP/TAZ are involved in normal GI mesenchymal differentiation and function as transcriptional co-repressors in a progenitor cell population. In this way, YAP/TAZ act as molecular gatekeepers prior to Hedgehog-mediated differentiation into smooth muscle cells. This work unveils a previously unknown requirement for Hippo pathway signaling in the mammalian GI tract and a novel mechanism wherein YAP/TAZ function as transcriptional co-repressors to maintain a mesenchymal progenitor cell population.
Permanent Link to this Itemhttp://hdl.handle.net/20.500.14038/32242
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