title: Visual circuit assembly requires fine tuning of the novel Ig transmembrane protein Borderless.
abstract: Establishment of synaptic connections in the neuropils of the developing nervous system requires the coordination of specific neurite-neurite interactions (i.e., axon-axon, dendrite-dendrite and axon-dendrite interactions). The molecular mechanisms underlying coordination of neurite-neurite interactions for circuit assembly are incompletely understood. In this report, we identify a novel Ig superfamily transmembrane protein that we named Borderless (Bdl), as a novel regulator of neurite-neurite interactions in Drosophila. Bdl induces homotypic cell-cell adhesion in vitro and mediates neurite-neurite interactions in the developing visual system. Bdl interacts physically and genetically with the Ig transmembrane protein Turtle, a key regulator of axonal tiling. Our results also show that the receptor tyrosine phosphatase leukocyte common antigen-related protein (LAR) negatively regulates Bdl to control synaptic-layer selection. We propose that precise regulation of Bdl action coordinates neurite-neurite interactions for circuit formation in Drosophila.
authors.affiliation: Department of Neurology and Neurosurgery, McGill Centre for Research in Neuroscience and Departments of Medicine and Biology, McGill University Health Centre, Montreal, Quebec H3G 1A4, Canada.
authors.forename: Scott
authors.initials: S
authors.lastname: Cameron
authors.forename: Wen-Tzu
authors.initials: WT
authors.lastname: Chang
authors.forename: Yixu
authors.initials: Y
authors.lastname: Chen
authors.forename: Yating
authors.initials: Y
authors.lastname: Zhou
authors.forename: Shaurya
authors.initials: S
authors.lastname: Taran
authors.forename: Yong
authors.initials: Y
authors.lastname: Rao
mesh_terms: D000818:Animals; D002450:Cell Communication / Q000235:genetics*; D015536:Down-Regulation / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D004331:Drosophila melanogaster / Q000201:enzymology / Q000235:genetics; D005260:Female; D050440:Immunoglobulin Subunits / Q000235:genetics; D007136:Immunoglobulins / Q000235:genetics / Q000502:physiology; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D009154:Mutation / Q000235:genetics; D009415:Nerve Net / Q000201:enzymology / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000502:physiology; D016501:Neurites / Q000502:physiology; D054557:Receptor-Like Protein Tyrosine Phosphatases / Q000235:genetics / Q000502:physiology; D014795:Visual Pathways / Q000201:enzymology / Q000502:physiology*
chemical_list: C000621726:Bdl protein, Drosophila; D029721:Drosophila Proteins; D050440:Immunoglobulin Subunits; D007136:Immunoglobulins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C427323:tutl protein, Drosophila; C117978:Lar protein, Drosophila; D054557:Receptor-Like Protein Tyrosine Phosphatases