title: A combinatorial semaphorin code instructs the initial steps of sensory circuit assembly in the Drosophila CNS.
abstract: Longitudinal axon fascicles within the Drosophila embryonic CNS provide connections between body segments and are required for coordinated neural signaling along the anterior-posterior axis. We show here that establishment of select CNS longitudinal tracts and formation of precise mechanosensory afferent innervation to the same CNS region are coordinately regulated by the secreted semaphorins Sema-2a and Sema-2b. Both Sema-2a and Sema-2b utilize the same neuronal receptor, plexin B (PlexB), but serve distinct guidance functions. Localized Sema-2b attraction promotes the initial assembly of a subset of CNS longitudinal projections and subsequent targeting of chordotonal sensory afferent axons to these same longitudinal connectives, whereas broader Sema-2a repulsion serves to prevent aberrant innervation. In the absence of Sema-2b or PlexB, chordotonal afferent connectivity within the CNS is severely disrupted, resulting in specific larval behavioral deficits. These results reveal that distinct semaphorin-mediated guidance functions converge at PlexB and are critical for functional neural circuit assembly.
authors.affiliation: The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Howard Hughes Medical Institute, Baltimore, MD 21205, USA.
authors.forename: Zhuhao
authors.initials: Z
authors.lastname: Wu
authors.forename: Lora B
authors.initials: LB
authors.lastname: Sweeney
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Ayoob
authors.forename: Kayam
authors.initials: K
authors.lastname: Chak
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Andreone
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ohyama
authors.forename: Rex
authors.initials: R
authors.lastname: Kerr
authors.forename: Liqun
authors.initials: L
authors.lastname: Luo
authors.forename: Marta
authors.initials: M
authors.lastname: Zlatic
authors.forename: Alex L
authors.initials: AL
authors.lastname: Kolodkin
mesh_terms: D000344:Afferent Pathways / Q000196:embryology / Q000502:physiology*; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D030801:Animals, Genetically Modified; D001369:Axons / Q000502:physiology; D001522:Behavior, Animal; D019521:Body Patterning / Q000235:genetics / Q000502:physiology*; D002490:Central Nervous System / Q000166:cytology / Q000196:embryology / Q000502:physiology*; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004625:Embryo, Nonmammalian; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000235:genetics; D008562:Membrane Glycoproteins / Q000378:metabolism; D009068:Movement / Q000502:physiology; D009154:Mutation / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D010812:Physical Stimulation; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D039961:Semaphorins / Q000145:classification / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014732:Vibration
chemical_list: D029721:Drosophila Proteins; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D011956:Receptors, Cell Surface; D039961:Semaphorins; C116484:plexB protein, Drosophila; D049452:Green Fluorescent Proteins; D000469:Alkaline Phosphatase