title: Escargot controls the sequential specification of two tracheal tip cell types by suppressing FGF signaling in Drosophila.
abstract: Extrinsic branching factors promote the elongation and migration of tubular organs. In the Drosophila tracheal system, Branchless (Drosophila FGF) stimulates the branching program by specifying tip cells that acquire motility and lead branch migration to a specific destination. Tip cells have two alternative cell fates: the terminal cell (TC), which produces long cytoplasmic extensions with intracellular lumen, and the fusion cell (FC), which mediates branch connections to form tubular networks. How Branchless controls this specification of cells with distinct shapes and behaviors is unknown. Here we report that this cell type diversification involves the modulation of FGF signaling by the zinc-finger protein Escargot (Esg), which is expressed in the FC and is essential for its specification. The dorsal branch begins elongation with a pair of tip cells with high FGF signaling. When the branch tip reaches its final destination, one of the tip cells becomes an FC and expresses Esg. FCs and TCs differ in their response to FGF: TCs are attracted by FGF, whereas FCs are repelled. Esg suppresses ERK signaling in FCs to control this differential migratory behavior.
authors.affiliation: Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.|Department of Biology, Kobe University Graduate School of Science, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8051, Japan.
authors.forename: Guangxia
authors.initials: G
authors.lastname: Miao
authors.affiliation: Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan shayashi@cdb.riken.jp.|Department of Biology, Kobe University Graduate School of Science, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8051, Japan.
authors.forename: Shigeo
authors.identifier: 0000-0001-7785-1290
authors.initials: S
authors.lastname: Hayashi
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics*; D002459:Cell Fusion; D019070:Cell Lineage / Q000235:genetics*; D002465:Cell Movement / Q000235:genetics; D029721:Drosophila Proteins / Q000502:physiology*; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics; D004625:Embryo, Nonmammalian; D005346:Fibroblast Growth Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D020935:MAP Kinase Signaling System / Q000235:genetics; D009024:Morphogenesis / Q000235:genetics*; D015398:Signal Transduction / Q000235:genetics; D014132:Trachea / Q000166:cytology / Q000196:embryology* / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; C467520:esg protein, Drosophila; D005346:Fibroblast Growth Factors
keywords: Cell migration; ERK signaling; FGF signaling; Tip cell; Tubulogenesis