Postnatal development of rat cerebellum: massive and transient accumulation of concanavalin A binding glycoproteins in parallel fiber axolemma.

Modifications of protein-bound sugars during postnatal development of rat cerebellum were studied. Glycoprotein-bound mannose accumulates, in the particulate fractions, at an earlier age than the bulk of glycoprotein sugar. This corresponds to a transient and massive accumulation of glycoproteins which bind to Concanavalin A (Con A). These glycoproteins were localized by using fluorescent Con A and the horseradish peroxidase-Con A method. Cerebellar white matter and the molecular layer bind massive amounts of Con A. The binding in the molecular layer is transient. It follows the same time course as the Con A-binding glycoproteins of particulate fractions, and it is largely confined to the axolemma of parallel fibers. Only growing or newly formed parallel fibers bind Con A. The disappearance of the binding is simultaneous with the maturation of parallel fibers and their synapse formation. These phenomena can be related to fiber growth and maturation and, also, to synapse formation. The possibility of a specific role of Con A-binding glycoproteins is discussed.