Olfactory neurons express a unique glycosylated form of the neural cell adhesion molecule (N-CAM).
mAb-based approaches were used to identify cell surface components involved in the development and function of the frog olfactory system. We describe here a 205-kD cell surface glycoprotein on olfactory receptor neurons that was detected with three mAbs: 9-OE, 5-OE, and 13-OE. mAb 9-OE immunoreactivity, unlike mAbs 5-OE and 13-OE, was restricted to only the axons and terminations of the primary sensory olfactory neurons in the frog nervous system. The 9-OE polypeptide(s) were immunoprecipitated and tested for cross-reactivity with known neural cell surface components including HNK-1, the cell adhesion molecule L1, and the neural cell adhesion molecule (N-CAM). These experiments revealed that 9-OE-reactive molecules were not L1 related but were a subset of the 200-kD isoforms of N-CAM. mAb 9-OE recognized epitopes associated with N-linked carbohydrate residues that were distinct from the polysialic acid chains present on the embryonic form of N-CAM. Moreover, 9-OE N-CAM was a heterogeneous population consisting of subsets both with and without the HNK-1 epitope. Thus, combined immunohistochemical and immunoprecipitation experiments have revealed a new glycosylated form of N-CAM unique to the olfactory system. The restricted spatial expression pattern of this N-CAM glycoform suggests a possible role in the unusual regenerative properties of this sensory system.
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Division of Basic Research, Children's Hospital Reserch Foundation, Cincinnati, Ohio 45229.
Akeson
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D000581:Amidohydrolases; D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D001923:Brain Chemistry; D002236:Carbohydrate Conformation; D015816:Cell Adhesion Molecules, Neuronal / Q000032:analysis*; D002490:Central Nervous System / Q000254:growth & development*; D005455:Fluorescent Antibody Technique; D015151:Immunoblotting; D007150:Immunohistochemistry; D007163:Immunosorbent Techniques; D037102:Lectins; D008856:Microscopy, Fluorescence; D008970:Molecular Weight; D009830:Olfactory Bulb / Q000032:analysis; D009831:Olfactory Mucosa / Q000032:analysis; D009832:Olfactory Nerve / Q000032:analysis*; D009833:Olfactory Pathways / Q000254:growth & development*; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D037121:Plant Lectins; D011892:Rana catesbeiana; D051381:Rats; D011919:Rats, Inbred Strains; D030262:Soybean Proteins; D013116:Spinal Cord / Q000032:analysis; D010835:Phytohemagglutinins
D000581:Amidohydrolases; D000911:Antibodies, Monoclonal; D015816:Cell Adhesion Molecules, Neuronal; D037102:Lectins; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D037121:Plant Lectins; D030262:Soybean Proteins; C028824:soybean lectin; D010835:Phytohemagglutinins