title: PlexinA1 signaling directs the segregation of proprioceptive sensory axons in the developing spinal cord.
abstract: As different classes of sensory neurons project into the CNS, their axons segregate and establish distinct trajectories and target zones. One striking instance of axonal segregation is the projection of sensory neurons into the spinal cord, where proprioceptive axons avoid the superficial dorsal horn-the target zone of many cutaneous afferent fibers. PlexinA1 is a proprioceptive sensory axon-specific receptor for sema6C and sema6D, which are expressed in a dynamic pattern in the dorsal horn. The loss of plexinA1 signaling causes the shafts of proprioceptive axons to invade the superficial dorsal horn, disrupting the organization of cutaneous afferents. This disruptive influence appears to involve the intermediary action of oligodendrocytes, which accompany displaced proprioceptive axon shafts into the dorsal horn. Our findings reveal a dedicated program of axonal shaft positioning in the mammalian CNS and establish a role for plexinA1-mediated axonal exclusion in organizing the projection pattern of spinal sensory afferents.
authors.affiliation: Howard Hughes Medical Institute, Department of Biochemistry and Molecular Biophysics, Center for Neurobiology and Behavior, Columbia University, New York, New York 10032, USA. yy2032@columbia.edu
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Barbara
authors.initials: B
authors.lastname: Han
authors.forename: Monica
authors.initials: M
authors.lastname: Mendelsohn
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Jessell
mesh_terms: D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D001369:Axons / Q000502:physiology*; D002642:Chick Embryo; D018274:Electroporation; D017403:In Situ Hybridization; D008024:Ligands; D051379:Mice; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology*; D009836:Oligodendroglia / Q000502:physiology; D020671:Posterior Horn Cells / Q000502:physiology; D011434:Proprioception / Q000502:physiology*; D011485:Protein Binding; D018075:RNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D011956:Receptors, Cell Surface / Q000502:physiology*; D039961:Semaphorins / Q000096:biosynthesis / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D012867:Skin / Q000294:innervation; D013116:Spinal Cord / Q000166:cytology / Q000254:growth & development / Q000502:physiology*
chemical_list: D008024:Ligands; D009419:Nerve Tissue Proteins; C492114:Plxna1 protein, mouse; D018075:RNA, Complementary; D011956:Receptors, Cell Surface; C504199:Sema6c protein, mouse; C483479:Sema6d protein, mouse; D039961:Semaphorins