title: Semaphorin-1a acts in concert with the cell adhesion molecules fasciclin II and connectin to regulate axon fasciculation in Drosophila.
abstract: Semaphorins comprise a large family of phylogenetically conserved secreted and transmembrane glycoproteins, many of which have been implicated in repulsive axon guidance events. The transmembrane semaphorin Sema-1a in Drosophila is expressed on motor axons and is required for the generation of neuromuscular connectivity. Sema-1a can function as an axonal repellent and mediates motor axon defasciculation. Here, by manipulating the levels of Sema-1a and the cell adhesion molecules fasciclin II (Fas II) and connectin (Conn) on motor axons, we provide further evidence that Sema-1a mediates axonal defasciculation events by acting as an axonally localized repellent and that correct motor axon guidance results from a balance between attractive and repulsive guidance cues expressed on motor neurons.
authors.affiliation: Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
authors.forename: H H
authors.initials: HH
authors.lastname: Yu
authors.forename: A S
authors.initials: AS
authors.lastname: Huang
authors.forename: A L
authors.initials: AL
authors.lastname: Kolodkin
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001369:Axons / Q000502:physiology*; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000502:physiology*; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000502:physiology*; D064211:Connectin; D003433:Crosses, Genetic; D004331:Drosophila melanogaster / Q000235:genetics / Q000502:physiology*; D005207:Fasciculation; D005260:Female; D005838:Genotype; D006023:Glycoproteins / Q000235:genetics / Q000502:physiology*; D008297:Male; D009124:Muscle Proteins / Q000235:genetics / Q000502:physiology*; D009414:Nerve Growth Factors / Q000235:genetics / Q000502:physiology*; D011494:Protein Kinases / Q000235:genetics / Q000502:physiology*; D040121:Semaphorin-3A
chemical_list: D015815:Cell Adhesion Molecules; D015816:Cell Adhesion Molecules, Neuronal; D064211:Connectin; D006023:Glycoproteins; D009124:Muscle Proteins; D009414:Nerve Growth Factors; D040121:Semaphorin-3A; C051642:fasciclin II; D011494:Protein Kinases