Huang, PengLim, Nicholas Farn Wei2024-06-272024-06-272024-06-25Lim, N. F. W. (2024). Elucidating the role of tcf15 in somite development (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.https://hdl.handle.net/1880/119042https://doi.org/10.11575/PRISM/46638Somites are transient embryonic structures that give rise to the axial musculoskeletal system. Eventually, the somite gives rise to three distinct compartments: the dermatome, myotome, and sclerotome. These compartments give rise to the skin, skeletal muscles, and the axial skeleton, respectively. Thus, proper formation of somitic compartment is necessary for a functional body. Despite many early studies elucidating the development of the somite, little is known about the regulator of somite compartment proportion. Here I characterized the basic helix-loop-helix transcription factor, tcf15, as a key regulator of somitic compartments in zebrafish. I showed that tcf15 expression is highly dynamic during somite development, with initial robust expression throughout the presomitic mesoderm, followed by restricted expression in the dermomyotome and ultimately in dermomyotome-derived muscle progenitors and in sclerotome-derived tenocytes along the somite boundary. Through mutant analysis, I found that loss of tcf15 results in a reduction in the pax7a+ dermomyotome and the myoD+ myotome compartment accompanied by an expansion of the nkx3.1+ sclerotome. Interestingly, migration of sclerotome cells and the development of sclerotome-derived cells such as tenocytes and fin mesenchymal cells were unaffected in tcf15 mutants. To manipulate Tcf15 activity, I developed various gain-of-function and loss-of function tools. However, the broad application of these tools was limited by technical challenges. Nonetheless, by combining the expression and mutant analysis, my results suggest that Tcf15 functions as an important regulator of somite compartmentalization in zebrafish, promoting the dermomyotome/myotome fate while repressing the sclerotome fate.enUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.Tcf15ZebrafishDevelopmentalBiologySomiteGeneticsBiology--Molecularmaster thesis