NEURONAL DIVERSIFICATION - DEVELOPMENT OF MOTOR-NEURON SUBTYPES

Recent progress has been made in defining the developmental mechanisms that contribute to the diversification of motor neuron subtypes, whic h differ in transcription factor gene expression and synaptic connecti ons. These studies suggest that progenitor cells acquire specific moto r neuron identities through the coordinate actions of multiple factors . Current evidence suggests that Sonic hedgehog initiates a common pat hway for motor neuron differentiation, while positionally distributed factors act to assign subtype identities.