Although it is becoming increasingly clear that many of the neuronal and glial cell-surface macromolecules involved in developmental processes and in other cell-cell interactions are glycosylated, relatively little is known concerning the specific functional roles of their carbohydrate moieties. This project therefore addresses the structural, developmental, and functional relationships of nervous tissue glycoproteins and proteoglycans. There are three specific aims: 1.) Heparan sulfate is a structurally highly variable glycosaminoglycan which is present in both plasma membranes and basement membranes of nervous tissue. He have recently demonstrated that significant alterations in the size, charge, and sulfation pattern of PC12 call heparan sulfate accompany NGF-induced differentiation and neuron outgrowth. He now plan to examine whether the enzymatic basis of this effect is through a stimulation by NGF of N-acetylheparosan deacetylase activity, and to determine in more detail the structural alterations in cell surface heparan sulfate which are produced by nerve growth factor. 2.) In previous studies we have found that antibodies to the chondroitin sulfate proteoglycan of brain interfere with cell aggregate formation in cerebellar cultures, and that B-xylosides, which inhibit proteoglycan biosynthesis, produce significant alterations in the morphology and adhesion of NGF-treated PC12 cells. We now plan to extend these investigations to determine the biochemical effects of B-xyiosides in both brain and PCl2 cells. 3.) A 130,000 Da brain-specific glycoprotein whose concentration increased during development is recognized by the F3- 87-8 monoclonal antibody. We will use this antibody in immunocytochemical studies to identify the cellular localization of the glycoprotein and its developmental changes. We will also examine its oligosaccharide structures, in glycoprotein purified by immunoaffinity chromatography from rat brain biosynthetically labeled by intracerebral administration of (3H) glycocyamine.
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|Flaccus, A; Janetzko, A; Tekotte, H et al. (1991) Immunocytochemical localization of chondroitin and chondroitin 4- and 6-sulfates in developing rat cerebellum. J Neurochem 56:1608-15|
|Margolis, R K; Goossen, B; Tekotte, H et al. (1991) Effects of beta-xylosides on proteoglycan biosynthesis and morphology of PC12 pheochromocytoma cells and primary cultures of rat cerebellum. J Cell Sci 99 ( Pt 2):237-46|
|Ripellino, J A; Margolis, R U; Margolis, R K (1989) Oligosaccharide composition, localization, and developmental changes of a CNS-specific (F3-87-8) glycoprotein. J Neurochem 53:1103-8|