The myelin-associated glycoprotein of the peripheral nervous system in trembler mutants contains increased α2–3 sialic acid and galactose
✍ Scribed by Z.P. Bartoszewicz; C.J. Lauter; R.H. Quarles
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 679 KB
- Volume
- 43
- Category
- Article
- ISSN
- 0360-4012
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✦ Synopsis
The myelin-associated glycoprotein (MAG) exhibits an abnormally high apparent molecular weight in sciatic nerve, but not in brain, of dysmyelinating trembler mutants (Inuzuka et al.: J Neurochem 44:79> 797,1985). Antibodies to the large and small isoforms of MAG (L-and S-MAG) and probes for oligosaccharide structure were used to determine if this was due to overexpression of L-MAG or increased glycosylation. Nerves from both control and trembler 36-dayold mice contained primarily S-MAG with only traces of L-MAG. The distribution of the two isoforms appeared normal in trembler mice, and both isoforms exhibited the higher apparent molecular weight. Lectin binding showed that, in contrast to brain in which most glycoproteins contain primarily a2-3 linked sialic acid, most glycoproteins of both control and trembler nerve contained primarily a2-6 linked sialic acid. Lectin binding and glycosidase treatments demonstrated that the higher molecular weight of MAG in trembler nerves was due to an increased content of a2-3 linked sialic acid and galactose. The abnormal glycosylation of MAG in trembler mutants may contribute to the myelin pathology.