title: Selective pathway choice of a single central axonal fascicle by a subset of peripheral neurons during leech development.
abstract: In the CNS of leech, the central projections of peripheral sensory neurons segregate into three distinct axonal tracts during early development. We have previously shown that a subset of these neurons, recognized by the monoclonal antibody lan 4-2, projects axons into only one of these fascicles (Johansen et al., 1992, Neuron 8, 599). Here we report on a developmental and biochemical characterization of another fascicle-specific antigen labeled by the monoclonal antibody lan 3-6. By immunocytochemistry and double labelings we demonstrate that the lan 3-6 epitope is expressed only by a small subgroup of the peripheral neurons in Macrobdella embryos. The axons of these neurons selectively fasciculate in the CNS, but to only one of the three lan 3-2-positive tracts, which is different from the previously described lan 4-2-positive tract. These observations support the existence of a hierarchy of guidance cues mediating specific tract formation in this system. A biochemical analysis of the antigen suggests that it is likely to be a glycosylated protein with a molecular weight of approximately 200 kDa. Thus, the restricted expression of the lan 3-6 antigen and its biochemical properties are consistent with the hypothesis that this antigen may be playing a role in axonal guidance.
authors.affiliation: Department of Zoology and Genetics, Iowa State University, Ames 50011.
authors.forename: K K
authors.initials: KK
authors.lastname: Briggs
authors.forename: K M
authors.initials: KM
authors.lastname: Johansen
authors.forename: J
authors.initials: J
authors.lastname: Johansen
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000941:Antigens / Q000032:analysis / Q000502:physiology; D001369:Axons / Q000502:physiology*; D007865:Leeches / Q000196:embryology / Q000502:physiology*; D008970:Molecular Weight; D009475:Neurons, Afferent / Q000502:physiology*; D010525:Peripheral Nerves / Q000502:physiology
chemical_list: D000911:Antibodies, Monoclonal; D000941:Antigens