title: Conserved roles for Slit and Robo proteins in midline commissural axon guidance.
abstract: In Drosophila, Slit at the midline activates Robo receptors on commissural axons, thereby repelling them out of the midline into distinct longitudinal tracts on the contralateral side of the central nervous system. In the vertebrate spinal cord, Robo1 and Robo2 are expressed by commissural neurons, whereas all three Slit homologs are expressed at the ventral midline. Previous analysis of Slit1;Slit2 double mutant spinal cords failed to reveal a defect in commissural axon guidance. We report here that when all six Slit alleles are removed, many commissural axons fail to leave the midline, while others recross it. In addition, Robo1 and Robo2 single mutants show guidance defects that reveal a role for these two receptors in guiding commissural axons to different positions within the ventral and lateral funiculi. These results demonstrate a key role for Slit/Robo signaling in midline commissural axon guidance in vertebrates.
authors.affiliation: Howard Hughes Medical Institute, Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA.
authors.forename: Hua
authors.initials: H
authors.lastname: Long
authors.forename: Christelle
authors.initials: C
authors.lastname: Sabatier
authors.forename: Le
authors.initials: L
authors.lastname: Ma
authors.forename: Andrew
authors.initials: A
authors.lastname: Plump
authors.forename: Wenlin
authors.initials: W
authors.lastname: Yuan
authors.forename: David M
authors.initials: DM
authors.lastname: Ornitz
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tamada
authors.forename: Fujio
authors.initials: F
authors.lastname: Murakami
authors.forename: Corey S
authors.initials: CS
authors.lastname: Goodman
authors.forename: Marc
authors.initials: M
authors.lastname: Tessier-Lavigne
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D006023:Glycoproteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D011971:Receptors, Immunologic / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D013131:Spine / Q000196:embryology / Q000502:physiology*; D000097905:Roundabout Proteins
chemical_list: D006023:Glycoproteins; D009419:Nerve Tissue Proteins; D011971:Receptors, Immunologic; D000097905:Roundabout Proteins; C120566:slit protein, vertebrate