Myelin is critical for the rapid conduction of action potentials in the vertebrate nervous system.The oligodendrocyte is the cell type responsible for producing myelin and ensheathing axons in central nervous system (CNS).During early neural development, oligodendrocyte progenitor cells (OPCs) can be produced from a small number of neuroepithelial cells in both dorsal and ventral spinal cords, and both subpopulations of oligodendrocytes can contribute to axonal myelination during development and remyelination after injury.Regardless of their embryonic origins, the development of OPCs appear to be regulated by the same set of regulatory molecules.While Olig2 is essential for the initial specification of OPC cells, the terminal differentiation of OPCs is controlled by the Sox 10 and Nkx2.2 transcription factors.Our recent studies revealed a stage-dependent regulation of oligodendrocyte differentiation by Nkx2.2 homeodomain transcription factor.The myelination process is highly regulated by a number of extrinsic and intrinsic mechanisms during normal development of the oligodendrocyte lineage.Although several key factors have been identified to be critical for axonal myelination in the peripheral nervous system, the molecular control of CNS myelination has remained a mystery.In this talk, Ⅰ will present evidence that nectin-like cell adhesion molecules (Necl) and receptor molecules may participate in early CNS myelination and possibly in myelin regenerative process as well.