The Drosophila DOCK family protein Sponge is required for development of the air sac primordium.
Dedicator of cytokinesis (DOCK) family genes are known as DOCK1-DOCK11 in mammals. DOCK family proteins mainly regulate actin filament polymerization and/or depolymerization and are GEF proteins, which contribute to cellular signaling events by activating small G proteins. Sponge (Spg) is a Drosophila counterpart to mammalian DOCK3/DOCK4, and plays a role in embryonic central nervous system development, R7 photoreceptor cell differentiation, and adult thorax development. In order to conduct further functional analyses on Spg in vivo, we examined its localization in third instar larval wing imaginal discs. Immunostaining with purified anti-Spg IgG revealed that Spg mainly localized in the air sac primordium (ASP) in wing imaginal discs. Spg is therefore predicted to play an important role in the ASP. The specific knockdown of Spg by the breathless-GAL4 driver in tracheal cells induced lethality accompanied with a defect in ASP development and the induction of apoptosis. The monitoring of ERK signaling activity in wing imaginal discs by immunostaining with anti-diphospho-ERK IgG revealed reductions in the ERK signal cascade in Spg knockdown clones. Furthermore, the overexpression of D-raf suppressed defects in survival and the proliferation of cells in the ASP induced by the knockdown of Spg. Collectively, these results indicate that Spg plays a critical role in ASP development and tracheal cell viability that is mediated by the ERK signaling pathway.
Department of Applied Biology, The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
Kazushge
K
Morishita
Department of Applied Biology, The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
Dang Ngoc
DN
Anh Suong
Department of Applied Biology, The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
Hideki
H
Yoshida
Department of Applied Biology, The Center for Advanced Insect Research, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan. Electronic address: myamaguc@kit.ac.jp.
Masamitsu
M
Yamaguchi
D000400:Air Sacs / Q000166:cytology / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D055785:Gene Knockdown Techniques; D020935:MAP Kinase Signaling System; D014132:Trachea / Q000166:cytology
D002352:Carrier Proteins; D029721:Drosophila Proteins; C559918:Spg protein, Drosophila; D048049:Extracellular Signal-Regulated MAP Kinases
ASP; DOCK; Drosophila; ERK signaling pathway; Sponge