Expression of recombinant myelin-associated glycoprotein in primary Schwann cells promotes the initial investment of axons by myelinating Schwann cells.
Open Access
- 1 September 1990
- journal article
- research article
- Published by Rockefeller University Press in The Journal of cell biology
- Vol. 111 (3), 1171-1182
- https://doi.org/10.1083/jcb.111.3.1171
Abstract
Myelin-associated glycoprotein (MAG) is an integral membrane protein expressed by myelinating glial cells that occurs in two developmentally regulated forms with different carboxyterminal cytoplasmic domains (L-MAG and S-MAG). To investigate the role of MAG in myelination a recombinant retrovirus was used to introduce a MAG cDNA (L-MAG form) into primary Schwann cells in vitro. Stably infected populations of cells were obtained that constitutively expressed MAG at the cell surface without the normal requirement for neuronal contact to induce expression. Constitutive expression of L-MAG did not affect myelination. In long term co-culture with purified sensory neurons, the higher level of MAG expression on infected Schwann cells was reduced to control levels on cells that formed myelin. On the other hand, unlike normal Schwann cells, infected Schwann cells associated with nonmyelinated axons or undergoing Wallerian degeneration expressed high levels of MAG. This suggests that a posttranscriptional mechanism modulates MAG expression during myelination. Immunostaining myelinating cultures with an antibody specific to L-MAG showed that L-MAG was normally transiently expressed at the earliest stages of myelination. In short term co-culture with sensory neurons, infected Schwann cells expressing only L-MAG segregated and ensheathed larger axons after 4 d in culture provided that an exogenous basal lamina was supplied. Similar activity was rarely displayed by control Schwann cells correlating with the low level of MAG induction after 4 d. These data strongly suggest that L-MAG promotes the initial investment by Schwann cells of axons destined to be myelinated.This publication has 38 references indexed in Scilit:
- Antibodies to the L1 adhesion molecule inhibit Schwann cell ensheathment of neurons in vitro.The Journal of cell biology, 1989
- Recombinant myelin-associated glycoprotein confers neural adhesion and neurite outgrowth functionNeuron, 1989
- Movements of the Schwann cell nucleus implicate progression of the inner (axon-related) Schwann cell process during myelination.The Journal of cell biology, 1989
- Transplantation of oligodendrocytes and Schwann cells into the spinal cord of the myelin-deficient ratJournal of Neurocytology, 1988
- Differentiation of axon-related Schwann cells in vitro. I. Ascorbic acid regulates basal lamina assembly and myelin formation.The Journal of cell biology, 1987
- Linkage Between Axonal Ensheathment and Basal Lamina Production by Schwann CellsAnnual Review of Neuroscience, 1986
- Expression of the neural cell adhesion molecules L1 and N-CAM and their common carbohydrate epitope L2/HNK-1 during development and after transection of the mouse sciatic nerveDifferentiation, 1985
- A Method for Isolation of Intact, Translationally Active Ribonucleic AcidDNA, 1983
- Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications.Proceedings of the National Academy of Sciences, 1979
- Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4Nature, 1970