My laboratory has been investigating mammalian neural development, using the murine trigeminal sensory system as a working model. Trigeminal neurons are responsible for sensory processing in the face, oral and nasal cavities, and develop sequentially from two populations of the neural precursors, the trigeminal placode and the neural crest. Two sets of experiments are proceeding at this moment. First, we are using a genetic approach to remove the placodal precursors and then to study how the development of the remained neural crest will be influenced. This study should enable us to reveal roles of cellular interaction in controlling neuronal differentiation and/or axonal pathfinding. Second, we have characterized two families of transcription factors that are expressed in both projecting sensory neurons and the target fields innervated by these neurons. We are investigating if these molecules play a role in controlling axonal projection and/or synaptic connection.