title: BOC, brother of CDO, is a dorsoventral axon-guidance molecule in the embryonic vertebrate brain.
abstract: The early axon scaffolding in the embryonic vertebrate brain consists of a series of ventrally projecting axon tracts that grow into a single major longitudinal pathway connected across the midline by commissures. We have investigated the role of Brother of CDO (BOC), an immunoglobulin (Ig) superfamily member distantly related to the Roundabout (Robo) family of axon-guidance receptors, in the development of this embryonic template of axon tracts in the zebrafish brain. A zebrafish homologue of BOC was isolated and shown to be expressed predominantly in the developing neural plate and later in the neural tube and developing brain. Zebrafish boc was initially highly localized to discrete bands in the mid- and hindbrain, but, as the major brain subdivisions emerged, it became more evenly expressed along the rostrocaudal axis, particularly in dorsal regions. The function of zebrafish boc was examined by a loss-of-function approach. Analysis of embryos injected with antisense morpholinos designed against boc revealed highly selective defects in the development of dorsoventrally projecting axon tracts. Loss of boc caused ventrally projecting axons, particularly those arising from the presumptive telencephalon, to follow aberrant trajectories. These data indicate that boc is an axon-guidance molecule playing a fundamental role in pathfinding during the early patterning of the axon scaffold in the embryonic vertebrate brain.
authors.affiliation: Brain Growth and Regeneration Laboratory, School of Biomedical Sciences, University of Queensland, Brisbane 4072, Queensland, Australia.
authors.forename: Robin M
authors.initials: RM
authors.lastname: Connor
authors.forename: Chelsea L
authors.initials: CL
authors.lastname: Allen
authors.forename: Christine A
authors.initials: CA
authors.lastname: Devine
authors.forename: Christina
authors.initials: C
authors.lastname: Claxton
authors.forename: Brian
authors.initials: B
authors.lastname: Key
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001369:Axons / Q000502:physiology*; D001921:Brain / Q000196:embryology* / Q000378:metabolism*; D018959:CD57 Antigens / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular / Q000379:methods; D004625:Embryo, Nonmammalian; D004627:Embryonic Induction / Q000187:drug effects / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000502:physiology*; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D051379:Mice; D008845:Microinjections / Q000379:methods; D018613:Microscopy, Confocal / Q000379:methods; D008958:Models, Molecular; D009025:Morpholines / Q000494:pharmacology; D019006:Neural Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D016571:Neural Networks, Computer; D018075:RNA, Complementary / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C474334:BOC protein, human; C000602627:BOC protein, zebrafish; D018959:CD57 Antigens; D007074:Immunoglobulin G; D009025:Morpholines; D019006:Neural Cell Adhesion Molecules; D018075:RNA, Complementary; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D029961:Zebrafish Proteins; D049452:Green Fluorescent Proteins