N-CADHERIN EXPRESSION AND FUNCTION IN CULTURED OLIGODENDROCYTES

N-Cadherin is a major cell adhesion molecule that is expressed in the developing nervous system where it has been implicated in neural migra tion and axon growth. Recently, a role for N-cadherin in oligodendrocy te differentiation has been identified [23]. Oligodendrocyte precursor s adhere to N-cadherin and mature rapidly to produce myelin sheets. Si nce this implies that oligodendrocytes express N-cadherin, we examined the expression of N-cadherin by oligodendrocytes in culture. N-Cadher in was expressed by O-2A progenitors, immature oligodendrocytes and ma ture oligodendrocytes, but at a lower level than in type 1 astrocytes in the same cultures. On mature oligodendrocytes, the N-cadherin was c oncentrated on the major processes emerging from the soma. The ability of N-cadherin and merosin to promote oligodendrocyte precursor migrat ion was also studied. Average migration rates were significantly highe r on merosin(11.2 mu m/h) than on N-cadherin(5.6 mu m/h). These result s suggest that N-cadherin is not likely to function predominantly as a substrate that stimulates migration of O-2A progenitors, but may be m ore important in initiating early oligodendrocyte-axon interactions th at promote the process of myelination.