Induction of oligodendrocyte fate during the formation of the vertebrate neural tube.

The development of the central nervous system (CNS) comprises a series of inductive and transforming events that includes rostro-caudal and dorso-ventral patterning, neuroglial specification and extensive cell migration. The patterning of the neural tube is also characterized by the transcription of specific genes, which encode for morphogens and transcription factors essential for cell fate specification. The generation of oligodendrocytes, the myelin forming glial cells in the CNS, appears to be restricted to specific domains localized in the ventral neuroepithelium. Signaling mediated by sonic hedgehog (Shh) seems to command the early phase of the specification of uncommitted neural stem cells into the oligodendroglial lineage. Once generated, oligodendrocyte progenitors have to follow a developmental program that involves changes in cell morphology, migratory capacity and sensitivity to extracellular trophic factors before becoming mature myelinating cells. This minireview aims to discuss molecular aspects of the early induction of oligodendroglial fate during the formation of the CNS.