title: Repulsion by Slit and Roundabout prevents Shotgun/E-cadherin-mediated cell adhesion during Drosophila heart tube lumen formation.
abstract: During Drosophila melanogaster heart development, a lumen forms between apical surfaces of contralateral cardioblasts (CBs). We show that Slit and its receptor Roundabout (Robo) are required at CB apical domains for lumen formation. Mislocalization of Slit outside the apical domain causes ectopic lumen formation and the mislocalization of cell junction proteins, E-cadherin (E-Cad) and Enabled, without disrupting overall CB cell polarity. Ectopic lumen formation is suppressed in robo mutants, which indicates robo's requirement for this process. Genetic evidence suggests that Robo and Shotgun (Shg)/E-Cad function together in modulating CB adhesion. robo and shg/E-Cad transheterozygotes have lumen defects. In robo loss-of-function or shg/E-Cad gain-of-function embryos, lumen formation is blocked because of inappropriate CB adhesion and an accumulation of E-Cad at the apical membrane. In contrast, shg/E-Cad loss-of-function or robo gain-of-function blocks lumen formation due to a loss of CB adhesion. Our data show that Slit and Robo pathways function in lumen formation as a repulsive signal to antagonize E-Cad-mediated cell adhesion.
authors.affiliation: Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854, USA.
authors.forename: Edgardo
authors.initials: E
authors.lastname: Santiago-Martínez
authors.forename: Nadine H
authors.initials: NH
authors.lastname: Soplop
authors.forename: Rajesh
authors.initials: R
authors.lastname: Patel
authors.forename: Sunita G
authors.initials: SG
authors.lastname: Kramer
mesh_terms: D000818:Animals; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D002448:Cell Adhesion / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D016764:Cell Polarity / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D022001:Focal Adhesions / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D006321:Heart / Q000196:embryology*; D006330:Heart Defects, Congenital / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D018919:Neovascularization, Physiologic / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D038081:Organogenesis / Q000235:genetics; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism*; D000097905:Roundabout Proteins
chemical_list: D015820:Cadherins; D029721:Drosophila Proteins; D009419:Nerve Tissue Proteins; D011971:Receptors, Immunologic; D000097905:Roundabout Proteins; C501889:shg protein, Drosophila; C066819:sli protein, Drosophila