Browsing by Author "Peskin, Brianna Claire"
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Item Embargo Uncovering the patterning mechanisms governing notochord segmentation and spine evolution(2022) Peskin, Brianna ClaireVertebrates are distinguished by the presence of a segmented spine that supports the body axis and facilitates movement. The establishment of alternating domains of vertebral centra and intervertebral discs is a complex biological phenomenon. Recent studies in teleost fish demonstrate that the epithelial sheath of the notochord segments to provide positional information for the development of vertebral bone. The studies performed for this dissertation uncover specific components of the gene regulatory network guiding notochord segmentation. Genetic manipulations and live confocal imaging of transgenic zebrafish demonstrate that BMP activity triggers sheath cell differentiation and regulates the lateral expansion of notochord segments. Moreover, the importance of notochord segmentation during the development and evolution of the spine is highlighted by a unique extracellular matrix mutant in which notochord patterning is lost. Without a segmented notochord framework, sclerotomal osteoblasts alter their migratory trajectories and solely rely on paraxial mesoderm patterning to form centra structures. The resulting mode of spine morphogenesis shares commonalities with basal gnathostome species, suggesting that notochord signals prompted specific morphological transitions during spine evolution.