UC Berkeley

Development consists of complex morphogenetic movements that shape individual tissues as well as the embryo. Tissues must interact both physically and through signaling molecules to coordinate the formation of various organs and the entire body plan. My thesis work sought to characterize tissue interactions that govern muscle formation during vertebrate embryo development using the African clawed frog Xenopus laevis as a model system.

Chapter 1 of this dissertation provides a general introduction to the morphogenetic events and molecular regulation leading to muscle formation. Chapter 2 presents two previously-undiscovered morphogenetic phenomena involving the muscle tissue as well as individual muscle fibers. My experiments confirmed the function and mechanisms of muscle tissue unfolding as well as the cell rearrangements that ultimately place muscle fibers into organized arrays for proper functioning. Chapter 3 summarizes my work to further analyze a previously-unreported reciprocal relationship between the neural tissue and the prospective muscle tissue. My work shows that the neural plate influences the size of the underlying muscle. Enlarging the neural plate results in a corresponding increase in the size of the muscle tissue. Here, I dissect the source and fate of ectopic muscle tissue and determine the effect of tissue size on muscle morphogenesis. As a whole, this work summarizes my research to characterize the molecular and morphological events necessary for proper muscle formation during embryo development.