NEUREGULIN AND ERBB RECEPTORS PLAY A CRITICAL ROLE IN NEURONAL MIGRATION

The migration of neuronal precursors along radial glial fibers is a cr itical step in the formation of the nervous system. In this report, we show that neuregulin-erbB receptor signaling plays a crucial role in the migration of cerebellar granule cells along radial glial fibers. G ranule cells express neuregulin (NRG), and radial glia cells express e rbB4 in the developing cerebellum and in vitro. When the glial erbB re ceptors are blocked, neurons fail to induce radial glia formation, and their migration along radial glial fibers is impaired. Moreover, solu ble NRG is as effective as neuron-glia contact in the induction of rad ial glia formation. These results suggest that the activation of glial erbB4 by NRG is an early critical step in the neuronal migration prog ram.