title: Borderless regulates glial extension and axon ensheathment.
abstract: Ensheathment of axons by glial processes is essential for normal brain function. While considerable progress has been made to define molecular and cellular mechanisms underlying the maintenance of axon ensheathment, less is known about molecular details of early events for the wrapping of axons by glial processes in the developing nervous system. In this study, we investigate the role of the transmembrane protein Borderless (Bdl) in the developing Drosophila visual system. Bdl belongs to the immunoglobulin (Ig) superfamily, and its in vivo function is unknown. We show that Bdl is expressed in wrapping glia (WG) in the developing eye disc. Cell-type-specific transgene rescue and knockdown indicate that Bdl is specifically required in WG for the extension of glial processes along photoreceptor axons in the optic lobe, and axon ensheathment. Our results identify Bdl as a novel glia-specific cell-surface recognition molecule in regulating glial extension and axon ensheathment.
authors.affiliation: McGill Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, McGill University Health Centre, 1650 Cedar Avenue, Montreal, Quebec, Canada H3G 1A4; Integrated Program in Neuroscience, McGill University Health Centre, 1650 Cedar Avenue, Montreal, Quebec, Canada H3G 1A4.
authors.forename: Scott
authors.initials: S
authors.lastname: Cameron
authors.affiliation: McGill Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, McGill University Health Centre, 1650 Cedar Avenue, Montreal, Quebec, Canada H3G 1A4.
authors.forename: Yixu
authors.initials: Y
authors.lastname: Chen
authors.affiliation: McGill Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, McGill University Health Centre, 1650 Cedar Avenue, Montreal, Quebec, Canada H3G 1A4; Integrated Program in Neuroscience, McGill University Health Centre, 1650 Cedar Avenue, Montreal, Quebec, Canada H3G 1A4; Department of Medicine, McGill University Health Centre, 1650 Cedar Avenue, Montreal, Quebec, Canada H3G 1A4. Electronic address: yong.rao@mcgill.ca.
authors.forename: Yong
authors.initials: Y
authors.lastname: Rao
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology* / Q000648:ultrastructure; D002465:Cell Movement; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D004331:Drosophila melanogaster / Q000254:growth & development* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D007814:Larva; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D055495:Neurogenesis; D009457:Neuroglia / Q000166:cytology* / Q000378:metabolism; D011679:Pupa; D019076:Transgenes; D014795:Visual Pathways / Q000254:growth & development*
chemical_list: C000621726:Bdl protein, Drosophila; D029721:Drosophila Proteins; D008565:Membrane Proteins
keywords: Axon ensheathment; Bdl; Drosophila; Eye disc; Glia