engleski

Myelin-associated glycoprotein ligands GD1a and GT1b are differently expressed in fiber tracts of mouse brain

Myelin-associated glycoprotein (MAG) is a myelin protein that inhibits neurite outgrowth by binding to its ligands: gangliosides GD1a and GT1b and/or Nogo receptor (NgR). MAG is a transmembrane protein localized on the innermost wrap of the myelin sheath where it binds its ligands on axonal membrane. Immunohistochemistry on mouse brain cut coronally, shows that MAG, GD1a and GT1b are expressed in fibers of stria terminalis and some parts of corpus callosum. The visualization of MAG is better if detergent (1% Triton X-100) is used in the blocking step. Since all proposed MAG ligands are lipid anchored molecules, use of detergent significantly changes their localization in tissue. To achieve better visualization of these ligands without the use of detergents, we presumed that longitudinally cut fiber tracts will show more immunoreactivity in the periaxonal space than if the same fiber tract is cut perpendicularly. To test our hypothesis, mouse brains were cut in three different planes (horizontal, sagittal and coronal) and stained on consecutive sections with antibodies to GD1a, GT1b and MAG with and without use of detergent. Visualization of MAG and its ganglioside ligands was enhanced in longitudinally cut fiber tracts in comparison to perpendicularly cut tracts. Differential expression of GD1a and GT1b was observed in different longitudinally cut fiber tracts.

myelin-associated glycoprotein; ganglioside; GD1a; GD1b

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