Myelin-associated glycoprotein and galactosylcerebroside expression in Schwann cells during myelination.

The temporo-spatial expression profiles of the myelin-associated glycoprotein (MAG) and galactosylcerebrosides (Gal-CBs) were analysed during Schwann cell differentiation and myelination in Schwann cell cultures and in dorsal root ganglion/Schwann cell cocultures. The temporal expression profiles demonstrate that the mechanisms triggering and regulating MAG and Gal-CBs are different and independent. They also provide further support for a role of MAG, but not Gal-CBs, in the establishment of the Schwann cell/axon interaction and in the formation of the primary mesaxon, while both MAG and Gal-CBs may participate in the further maturation of the mesaxon. The spatial expression profiles demonstrate that although Gal-CBs are concentrated in the same structures (mesaxonal spirals, paranodes and Schmidt-Lanterman incisures) as MAG in both developing and mature sheaths, where it is therefore possible that the two might have complementary functions, they are also present in regions from which MAG is excluded.