Fibroblast Growth Factors Influence Collective Cell Behavior During Mesoderm Migration

Citation

McMahon, Amy Jeanette (2010) Fibroblast Growth Factors Influence Collective Cell Behavior During Mesoderm Migration. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/G4RJ-7158. https://resolver.caltech.edu/CaltechTHESIS:03122010-112724332

Abstract

Collective cell migration is a complex process that occurs in development and disease. As a result, understanding migration has become an important topic in biology. Several models have been developed over the last decade, but these models lack enough diversity to encompass the many different types of migration. Therefore, we propose to add mesoderm migration in Drosophila melanogaster as a model for collective migration. Mesoderm migration involves the movement of hundreds of cells in concert, a process that occurs in many developing animals especially during gastrulation. We have developed a technique for studying mesoderm migration in vivo using two-photon microscopy and subsequent quantitative analyses. Using this technique, we explored the role of fibroblast growth factors (FGFs) during migration of the mesoderm. Drosophila embryos exhibit a simplified FGF signaling pathway, with two ligands interacting with one receptor, making it an ideal system for addressing two complementary questions. Firstly, we investigated what role FGF signaling plays in collective cell migration. At the same time, we were able to ask whether both FGF ligands are required for mesoderm migration, as it is an unanswered question in the FGF field whether FGF ligands function redundantly. We found that during mesoderm migration FGF signaling is required for movement of mesoderm cells toward the ectoderm, and that both ligands are involved. We found some evidence of functional redundancy, but also found that each ligand tended to play a dominant role during different developmental events. In addition, we discovered that mesoderm migration is a multistep process, with only a subset of steps requiring FGF signaling. As a result, we have established the role of FGF during mesoderm migration and opened up many interesting avenues for further study.

Thesis Files