Associate Professor, Neuroscience
PO Box 801392
Spinal Cord Development and Motor Neuron Differentiation
I am interested in understanding the molecular mechanisms that control the generation of different neuronal types along the anterior-posterior (A-P) axis of the spinal cord, using motor neurons as a model system. Spinal motor neurons in the ventral spinal cord extend axons to innervate peripheral muscle targets originating at equivalent A-P levels during embryonic development. I am studying the functions of the Hox-c cluster genes in order to understand how different motor neurons are generated along the A-P axis and how motor neuron identity affects axonal path finding and target selection. Different Hox-c cluster genes are expressed in distinct but overlapping domains along the A-P axis of the spinal cord. Using chick neural explants in an in vitro culture system, I have demonstrated that both paraxial mesoderm and tissues around Hensen's node initiate the patterned expression of different Hox-c genes in the spinal cord. The secreted molecules from these tissues that induce this patterning event include Fgf8, Gdf11, and retinoic acid. Currently, I am trying to identify genes acting down-stream of these signaling molecules that are required for patterned Hox-c gene expression. I am also addressing the functions of Hox-c genes in defining motor neuron identity and target selection by mis-expressing or removing Hox-c gene function specifically in the spinal motor neurons using transgenic approaches.