title: UNC5C is required for spinal accessory motor neuron development.
abstract: In both invertebrates and vertebrates, UNC5 receptors facilitate chemorepulsion away from a Netrin source. Unlike most motor neurons in the embryonic vertebrate spinal cord, spinal accessory motor neuron (SACMN) cell bodies and their axons translocate along a dorsally directed trajectory away from the floor plate/ventral midline and toward the lateral exit point (LEP). We have recently shown that Netrin-1 and DCC are required for the migration of SACMN cell bodies, in vivo. These observations raised the possibility that vertebrate UNC5 proteins mediate the presumed repulsion of SACMN away from the Netrin-rich ventral midline. Here, we show that SACMN are likely to express UNC5A and UNC5C. Whereas SACMN development proceeds normally in UNC5A null mice, many SACMN cell bodies fail to migrate away from the ventral midline and inappropriately cluster in the ventrolateral spinal cord of mouse embryos lacking UNC5C. These results support an important role for UNC5C in SACMN development.
authors.affiliation: Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors.forename: A K
authors.initials: AK
authors.lastname: Dillon
authors.forename: A R
authors.initials: AR
authors.lastname: Jevince
authors.forename: L
authors.initials: L
authors.lastname: Hinck
authors.forename: S L
authors.initials: SL
authors.lastname: Ackerman
authors.forename: X
authors.initials: X
authors.lastname: Lu
authors.forename: M
authors.initials: M
authors.lastname: Tessier-Lavigne
authors.forename: Z
authors.initials: Z
authors.lastname: Kaprielian
mesh_terms: D000055:Accessory Nerve / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D000818:Animals; D003423:Critical Period, Psychological; D004622:Embryo, Mammalian; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D051379:Mice; D018345:Mice, Knockout; D009046:Motor Neurons / Q000502:physiology*; D000075386:Netrin Receptors; D011247:Pregnancy; D011956:Receptors, Cell Surface / Q000172:deficiency; D017475:Receptors, Nerve Growth Factor / Q000172:deficiency / Q000378:metabolism*; D013116:Spinal Cord / Q000166:cytology / Q000196:embryology / Q000378:metabolism
chemical_list: D000075386:Netrin Receptors; D011956:Receptors, Cell Surface; D017475:Receptors, Nerve Growth Factor; C000617308:Unc5A protein, mouse; C105653:Unc5c protein, mouse