title: Expression of galectin-1 in the mouse olfactory system.
abstract: Primary sensory olfactory axons arise from the olfactory neuroepithelium that lines the nasal cavity and then project via the olfactory nerve into the olfactory bulb. The beta-galactoside binding lectin, galectin-1, and its laminin ligand have been implicated in the growth of these axons along this pathway. In galectin-1 null mutant mice, a subpopulation of primary sensory olfactory axons fails to reach its targets in the olfactory bulb. In the present study we examined the spatiotemporal expression pattern of galectin-1 in normal mice in order to understand its role in the development of the olfactory nerve pathway. At E15.5, when olfactory axons have already contacted the olfactory bulb, galectin-1 was expressed in the cartilage and mesenchyme surrounding the nasal cavity but was absent from the olfactory neuroepithelium, nerve and bulb. Between E16.5 and birth galectin-1 began to be expressed by olfactory nerve ensheathing cells in the lamina propria of the neuroepithelium and nerve fibre layer. Galectin-1 was neither expressed by primary sensory neurons in the olfactory neuroepithelium nor by their axons in the olfactory nerve. Laminin, a galectin-1 ligand, also exhibited a similar expression pattern in the embryonic olfactory nerve pathway. Our results reveal that galectin-1 is dynamically expressed by glial elements within the nerve fibre layer during a discrete period in the developing olfactory nerve pathway. Previous studies have reported galectin-1 acts as a substrate adhesion molecule by cross-linking primary sensory olfactory neurons to laminin. Thus, the coordinate expression of galectin-1 and laminin in the embryonic nerve fibre layer suggests that these molecules support the adhesion and fasciculation of axons en route to their glomerular targets.
authors.affiliation: Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Vic., Australia.
authors.forename: J
authors.initials: J
authors.lastname: Tenne-Brown
authors.forename: A C
authors.initials: AC
authors.lastname: Puche
authors.forename: B
authors.initials: B
authors.lastname: Key
mesh_terms: D000818:Animals; D001369:Axons / Q000737:chemistry; D002356:Cartilage / Q000737:chemistry / Q000196:embryology; D004848:Epithelium / Q000737:chemistry / Q000196:embryology; D037483:Galectin 1; D006388:Hemagglutinins / Q000032:analysis*; D007797:Laminin / Q000032:analysis; D008297:Male; D008648:Mesoderm / Q000737:chemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D009296:Nasal Cavity / Q000737:chemistry / Q000196:embryology; D009832:Olfactory Nerve / Q000737:chemistry / Q000196:embryology*; D009833:Olfactory Pathways / Q000737:chemistry* / Q000196:embryology*; D009928:Organ Specificity
chemical_list: D037483:Galectin 1; D006388:Hemagglutinins; D007797:Laminin