title: Presence of novel N-CAM glycoforms in the rat olfactory system.
abstract: The functional activity of the neural cell adhesion molecule N-CAM can be modulated by posttranslational modifications such as glycosylation. For instance, the long polysialic acid side chains of N-CAM alter the adhesion properties of the protein backbone. In the present study, we identified two novel carbohydrates present on N-CAM, NOC-3 and NOC-4. Both carbohydrates were detected on N-CAM glycoforms expressed by subpopulations of primary sensory olfactory neurons in the rat olfactory system. Based on the expression of NOC-3 and NOC-4 and the olfactory marker protein (OMP), four independent subpopulations of primary sensory olfactory neurons were characterized. These neurons expressed: both NOC-3 and NOC-4 but not OMP; both NOC-4 and OMP but not NOC-3; NOC-3, NOC-4, and OMP together; and OMP alone. The NOC-3- and NOC-4-expressing neurons were widely dispersed in the olfactory neuroepithelium lining the nasal cavity. The axons of NOC-4 expressing neurons innervated all glomeruli in the olfactory bulb, whereas the NOC-3 expressing axons terminated in a discrete subset of glomeruli scattered throughout the whole olfactory bulb. We propose that both NOC-3 and NOC-4 are part of a chemical code of olfactory neurons which is used in establishing the topography of connections between the olfactory neuroepithelium and the olfactory bulb.
authors.affiliation: Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Australia.
authors.forename: B
authors.initials: B
authors.lastname: Dowsing
authors.forename: A
authors.initials: A
authors.lastname: Puche
authors.forename: C
authors.initials: C
authors.lastname: Hearn
authors.forename: B
authors.initials: B
authors.lastname: Key
mesh_terms: D000818:Animals; D007150:Immunohistochemistry; D019006:Neural Cell Adhesion Molecules / Q000737:chemistry / Q000378:metabolism*; D009830:Olfactory Bulb / Q000378:metabolism*; D009833:Olfactory Pathways / Q000378:metabolism*; D051381:Rats
chemical_list: D019006:Neural Cell Adhesion Molecules