title: Gap junction channel protein innexin 2 is essential for epithelial morphogenesis in the Drosophila embryo.
abstract: Direct communication of neighboring cells by gap junction channels is essential for the development of tissues and organs in the body. Whereas vertebrate gap junctions are composed of members of the connexin family of transmembrane proteins, in invertebrates gap junctions consist of Innexin channel proteins. Innexins display very low sequence homology to connexins. In addition, very little is known about their cellular role during developmental processes. In this report, we examined the function and the distribution of Drosophila Innexin 2 protein in embryonic epithelia. Both loss-of-function and gain-of-function innexin 2 mutants display severe developmental defects due to cell death and a failure of proper epithelial morphogenesis. Furthermore, immunohistochemical analyses using antibodies against the Innexins 1 and 2 indicate that the distribution of Innexin gap junction proteins to specific membrane domains is regulated by tissue specific factors. Finally, biochemical interaction studies together with genetic loss- and gain-of-function experiments provide evidence that Innexin 2 interacts with core proteins of adherens and septate junctions. This is the first study, to our knowledge, of cellular distribution and protein-protein interactions of an Innexin gap junctional channel protein in the developing epithelia of Drosophila.
authors.affiliation: Institut für Molekulare Physiologie und Entwicklungsbiologie der Universität Bonn, Abt. für Molekulare Entwicklungsbiologie, 53115 Bonn, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Bauer
authors.forename: Corinna
authors.initials: C
authors.lastname: Lehmann
authors.forename: Julia
authors.initials: J
authors.lastname: Martini
authors.forename: Franka
authors.initials: F
authors.lastname: Eckardt
authors.forename: Michael
authors.initials: M
authors.lastname: Hoch
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D017630:Connexins / Q000276:immunology / Q000378:metabolism*; D029721:Drosophila Proteins / Q000276:immunology / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism; D004848:Epithelium / Q000196:embryology* / Q000378:metabolism*; D017629:Gap Junctions / Q000737:chemistry / Q000378:metabolism*; D009024:Morphogenesis; D011485:Protein Binding; D021381:Protein Transport
chemical_list: D017630:Connexins; D029721:Drosophila Proteins; C120024:inx2 protein, Drosophila