<p>Early Xenopus laevis development involves highly complex morphogenic movements. Two key movements are gastrulation, which establishes germ layer spatial arrangement, and neurulation, which results in the folding and closure of the neural tube. Multiple signaling pathways are involved in regulating cell adhesion, migration, shape and polarity during these processes to ensure normal development. Two of the most characterized pathways are the canonical and non-canonical Wnt pathways. However, the roles of all the individual molecules involved are not fully understood. In this thesis I provide initial characterization of the POZ-ZF transcription factor xZnf131. Znf131 is a transcriptional activator and its binding partner Kaiso negatively regulates this function. Since Znf131 and Kaiso display antagonistic roles and Kaiso mediates Wnt signaling and morphogenesis during Xenopus gastrulation and neurulation I hypothesize that xZnf131 is also required to regulate morphogenesis during these key developmental events.</p> <p>Like other POZ-ZF proteins, xZnf131 contains an amino-terminal POZ domain and a carboxy-terminal ZF domain comprised of five zinc fingers. xZnf131 is continuously expressed through early Xenopus development but was spatially localized to the dorsal and anterior structures of the embryo, notably the neural plate. Morpholino oligonucleotide (MO) knockdown of xZnf131 resulted in severe defects in notochord and neural plate formation, with abnormal cell morphology, typical of non-canonical Wnt misregulation. Interestingly, xZnf131 overexpression produced phenotypes very similar to xZnf131 knockdown suggesting that xZnf131 protein levels need to be tightly maintained to regulate the correct/normal morphogenic movements during Xenopus gastrulation and neurulation.</p> <p>Our findings indicate that xZnf131 plays a role in the morphogenic movements during Xenopus gastrulation and neurulation. Our data provides a useful foundation for future experiments to elucidate the biological mechanism of xZnf131 action during these key developmental processes.</p> / Master of Science (MSc)