Functional analysis of cytoplasmic protein methylation during neural crest migration

University of Minnesota Ph.D. dissertation. August 2013. Major: Molecular, Cellular, Developmental Biology and Genetics. Advisor: Laura S. Gammill. 1 computer file (PDF); xii, 175 pages, appendix A.Neural crest cells (NCCs) are multipotent, migratory cells that arise from the dorsal neural tube and migrate extensively throughout the vertebrate embryo to form a diverse set of lineages including melanocytes, craniofacial bone and most of the peripheral nervous system (LeDouarin and Kalcheim, 1999). Neural crest cells have attracted the attention of developmental biologist for over a century as a model system to study embryonic induction, specification, tissue commitment, cell-fate determination and migratory potential. An established gene regulatory network of transcription factors defines pathways that regulate a complex series of events from early induction to migration (Sauka-Spengler and Bronner-Fraser, 2008). However, the molecular events that take place following neural crest induction that trigger neural crest cells, and not other cells of the neural tube, to migrate are poorly understood. An induction of actin cytoskeletal elements in premigratory neural crest precursors prior to their migration, along with the fact that not all cells in the neural folds migrate suggests an additional layer of complexity to genetic and epigenetic control (Bronner-Fraser and Fraser, 1988, Selleck and Bronner-Fraser, 1995). It was postulated by analogy with other migratory cell types, that instead of a gene or epigenetic mark specifically marking a cell for migration, a signal to migrate mobilizes migratory potential in a subset of cells through post-transcriptional or post-translational regulation. For my thesis, I have examined a previously unrecognized role for post-translational non-histone protein methylation in regulating the migration of neural crest cells from the neural tube. I have studied the function of the essential methylation cycle enzyme SAHH, the methyltransferase Ezh2, as well as several targets of non-histone protein methylation including the actin-binding protein EF1a1, addressing their roles in neural crest cell specification and migration