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Schwann cells depleted of galactocerebroside express myelin‐associated glycoprotein and initiate but do not continue the process of myelination
Author(s) -
Owens Geoffrey C.,
Bunge Richard P.
Publication year - 1990
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/glia.440030205
Subject(s) - galactocerebroside , axon , schwann cell , biology , myelin , basal lamina , axolemma , microbiology and biotechnology , dorsal root ganglion , myelin associated glycoprotein , colocalization , immunostaining , oligodendrocyte , cytoplasm , neuroscience , anatomy , immunology , ultrastructure , central nervous system , immunohistochemistry , spinal cord
Two peripheral myelin components, galactocerebroside (GalC) and myelin‐associated glycoprotein (MAG), are known to be expressed early in Schwann cell differentiation, prior to the formation of definitive myelin segments containing compacted membrane. To discern the relative roles of these myelin components, cultures of Schwann cells and dorsal root ganglion neurons were treated with antigalactocerebroside mAbs in order to remove GalC from the Schwann cell surface (Ranscht et al., 1987). In the continuous presence of anti‐GalC antibodies and in a medium containing serum plus ascorbic acid, Schwann cells assemble a basal lamina and progress to the one:one stage of Schwann cell:axon interaction but do not differentiate further. Immunostaining with anti‐MAG antibodies revealed that GalC‐depleted Schwann cells expressed high levels of MAG. Double staining with anti‐MAG and anti‐Po antibodies showed that there was essentially no Po immunoreactivity in the same cells. In those Schwann cells that had attained a one:one association with large‐diameter axons, the inner‐axon‐related cytoplasmic process had passed under the outer mesaxon but had not completed a full turn around the axon. The expression of MAG on the single cytoplasmic process apposed to the axon in Schwann cells depleted of GalC further implicates MAG in the initial envelopment of the axon during myelination.