Mary E (Betsy) Pownall
During embryonic development, cells become committed to the skeletal muscle cell lineage and activate the expression of the myogenic regulatory genes MyoD and Myf5. These genes are dominant regulators of myogenesis and may provide a paradigm for how all cell lineages are determined. My lab is interested in how the earliest expression of the myogenic regulatory genes is activated during the development of Xenopus laevis and Xenopus tropicalis. We have shown that embryonic Fibroblast Growth Factor (eFGF), homologue of mammalian FGF4, is essential for the initial activation of MyoD (Fisher et al 2002). FGF ligands signal by binding receptor tyrosine kinases and this interaction requires the presence of heparan sulfate proteglycans. We recently have become interested in an enzyme called XtSulf-1 that post-synthetically modifies the structure of HSPGs and by doing so influences developmental cell signals. We have shown that Sulf-1 can negatively regulated FGF signaling in frog embryos (Wang et al 2004). The developmental expression of the XtSulf-1 gene is highly regulated and its protein localizes to the outside of the cell. We are investigating how the presence of Sulf-1 can influence the ability of cells in the embryos to respond to local developmental signals.
Lab MembershipsPownall Lab (Principal Investigator/Director)
British Xenopus Group (Other)