S. Bartsch et al., INCREASED NUMBER OF UNMYELINATED AXONS IN OPTIC NERVES OF ADULT MICE DEFICIENT IN THE MYELIN-ASSOCIATED GLYCOPROTEIN (MAG), Brain research, 762(1-2), 1997, pp. 231-234
We have recently demonstrated that the formation of myelin sheaths in
the optic nerve of young postnatal mice deficient in the myelin-associ
ated glycoprotein (MAG) is retarded when compared to age-matched wild-
type mice. In the present study, we analyzed whether impaired myelinat
ion of retinal ganglion cell axons is detectable in adult MAG mutants.
In optic nerves of 2- and 9-month-old MAG-deficient mice, we observed
a significantly increased number of unmyelinated axons compared to ag
e-matched wild-type mice. At both ages, unmyelinated axons in optic ne
rves of MAG mutants were of small caliber. The number of unmyelinated
axons decreased significantly in 9-month-old MAG mutants when compared
to 2-month-old MAG mutants, indicative of a slow and long-lasting mye
lination of axons in the mutant. Our observations support the view tha
t MAG is involved in the initiation of myelination in the CNS. (C) 199
7 Elsevier Science B.V.