Distinct functions of the leucine-rich repeat transmembrane proteins capricious and tartan in the Drosophila tracheal morphogenesis.
A key step in organogenesis of the Drosophila tracheal system is the integration of isolated tracheal metameres into a connected tubular network. The interaction of tracheal cells with surrounding mesodermal cells is crucial in this process. In particular, single mesodermal cells called bridge-cells are essential for the guided outgrowth of dorsal trunk branches to direct formation of the main airway, the dorsal trunk. Here, we present evidence that the two leucine-rich repeat transmembrane proteins Capricious and Tartan contribute differently to the formation of branch interconnections during tracheal development. Capricious is specifically localized on the surface of bridge-cells and facilitates the outgrowing dorsal trunk cells of adjacent metameres toward each other. We show that Capricious requires both extracellular and intracellular domains during tracheal branch outgrowth. In contrast, Tartan is expressed broadly in mesodermal cells and exerts its role in tracheal branch outgrowth through its extracellular domain. We propose that Capricious contributes to the instructive role of bridge-cells whereas Tartan provides permissive substrate for the migrating tracheal cells during the network formation.
Krause
Cindy
C
Abteilung Molekulare Entwicklungsbiologie, Max-Planck-Institut für biophysikalische Chemie, Am Fassberg, D-37077 Göttingen, Germany.
Wolf
Christian
C
Hemphälä
Johanna
J
Samakovlis
Christos
C
Schuh
Reinhard
R
D000595:Amino Acid Sequence; D000818:Animals; D002465:Cell Movement / Q000502:physiology; D029721:Drosophila Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000502:physiology*; D004331:Drosophila melanogaster / Q000737:chemistry / Q000196:embryology*; D007930:Leucine / Q000737:chemistry*; D000090263:Leucine-Rich Repeat Proteins; D008565:Membrane Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000502:physiology*; D008969:Molecular Sequence Data; D011506:Proteins / Q000737:chemistry / Q000502:physiology*; D014132:Trachea / Q000196:embryology*
D029721:Drosophila Proteins; D000090263:Leucine-Rich Repeat Proteins; D008565:Membrane Proteins; D011506:Proteins; C113006:caps protein, Drosophila; C084647:trn protein, Drosophila; D007930:Leucine