Tomacula in MAG-deficient mice.
The pathogenesis of tomacula in mice with a null mutation of the myelin-associated glycoprotein (MAG) gene is not well understood. This study, using a novel teased nerve fiber technique, demonstrates that tomacula in MAG-deficient mice are formed by redundant myelin infoldings and outfoldings in the paranodal regions as early as 4 weeks after birth and increase in size and frequency with age. Although tomacula show degenerative changes with increasing age, there was no significant evidence of demyelination/remyelination. Longitudinal sections of normal teased nerve fibers show early redundant myelin foldings in externally normal paranodal regions. These data and the absence of internodal tomacula support a role for MAG in the maintenance of myelin at the paranodal regions.
D000818:Animals; D015417:Hereditary Sensory and Motor Neuropathy / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout; D009186:Myelin Sheath / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D018992:Myelin-Associated Glycoprotein / Q000172:deficiency* / Q000235:genetics; D009410:Nerve Degeneration / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D009412:Nerve Fibers / Q000378:metabolism / Q000473:pathology
D018992:Myelin-Associated Glycoprotein