SYNAPTIC VESICLE AND SYNAPTIC MEMBRANE-GLYCOPROTEINS DURING PRENATAL-DEVELOPMENT AND POSTNATAL-DEVELOPMENT OF MOUSE CEREBRAL-CORTEX, CEREBELLUM AND SPINAL-CORD

Glycoproteins of synaptic vesicles and synaptic membranes play an impo rtant role during the process of synaptogenesis. In order to study the temporal expression of specific carbohydrates and the expression of s elected neural proteins, we used peroxidase-conjugated lectin overlays on Western blots and immunoblots of synaptic vesicles and synaptic me mbranes isolated from pre- and postnatal mouse cerebral cortex, cerebe llum and spinal cord. Our lectin overlays on Western blots showed that (1) the synaptic vesicle glycoproteins, gp80-100, gp47 and gp44, and (2) the synaptic membrane glycoproteins, gp180, gp72, gp70 and gp34, s how temporal regulation of expression of carbohydrate moieties. Quite significantly, gp47 showed a decrease in the vesicles coinciding with an increase in membranes suggesting a shift in localization. Anti neur al cell adhesion molecule (N-CAM) antibody cross-reacted with gp180. T he developmental expression of synaptotagmin 1, a well characterized g lycoprotein of synaptic vesicle, was determined by immunoblots analysi s. Anti synaptosomal-associated protein 25 (SNAP-25) antibody immunobl ots were performed in order to compare our results with a developmenta lly regulated synaptosomal protein demonstrating expression coincident with synaptogenesis. Our immunoblot studies showed that (1) N-CAM (gp 180) immunoreactivity decrease with development; (2) the expression of synaptotagmin 1 and SNAP-25 increases as development progresses, and (3) synaptotagmin 1 and SNAP-25 show a shift in subcellular localizati on (from synaptic vesicle to synaptic membrane) during development, th ereby indicating that these proteins are first identified in a vesicul ar fraction. Thus, our data suggest that synaptic vesicle and synaptic membrane glycoproteins show temporal regulation of specific carbohydr ates as well as protein expression during development, which may be a key factor to our understanding of the process of synaptogenesis.