The neurogenic placodes; a source of restricted sensory neuronal progenitor cells. (360G-Wellcome-078818_Z_05_Z)

Neurogenic placodes are focal thickenings of the embryonic ectoderm that form on the surface of the head of the embryo. It is within these structures that the precursors of the majority of the sensory neurons of the cranial ganglia are specified, and it is from the placodes that these sensory neuronal cells delaminate and then migrate internally to the site of ganglion formation. Importantly, particular placodes generate specific types of sensory neurons. A number of lines of evidence suggest that the cells released by, and migrating from the placodes, may be restricted sensory neuronal progenitor cells. We will use tissue transplantation to determine if the neuronal cells produced by the placodes are committed to particular sensory fates. We will also use in vitro approaches to assess the potential of these cells. We will analyse the role of SoxB1 genes, which are required to maintain neuronal progenitor cells in the CNS, in the formation of placodal derived neuronal progenitor cells. Finally, we will determine if the Sox2 expressing cells in the cranial ganglia of mouse embryos are also restricted sensory neuronal progenitor cells, and whether these cells can generate renewable precursors in vitro.