Coupling of Jun amino-terminal kinase and Decapentaplegic signaling pathways in Drosophila morphogenesis.
Dorsal closure in Drosophila embryos involves the migration of two lateral epithelia toward the dorsal midline to establish the dorsal ectoderm. Previous work showed that this morphogenetic movement depends on the activities of a Jun amino (N)-terminal kinase kinase (JNKK) encoded by the hemipterous (hep) gene, and of a JNK encoded by basket. Hep is required for cell determination in the leading edge of migrating epithelia, by controlling specific expression of the puckered (puc) gene in these cells. During dorsal closure, decapentaplegic (dpp), a member of the transforming growth factor-beta (TGF-beta) superfamily, is expressed in the row of cells making up the leading edge of the epithelia. Here, we show that the small GTPases Dcdc42, Drac1, and the Hep JNKK control dpp expression in this migratory process. Appropriate dpp and puc expression in the leading edge also depends on the inhibitory function of the puc gene. Further, our data suggest that the leading edge is the source of a JNK autocrine signal, and exclude a role of Dpp as such a ligand. Dorsal closure couples JNK and dpp signaling pathways, a situation that may be conserved in vertebrate development.
Glise
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Centre de Biologie du Développement, Unité Mixte de Recherche (UMR)5547-Centre National de la Recherche Scientifique (CNRS), Toulouse, France.
Noselli
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D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins; D019204:GTP-Binding Proteins / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D019476:Insect Proteins / Q000235:genetics*; D048031:JNK Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D009024:Morphogenesis; D011494:Protein Kinases / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D015398:Signal Transduction; D015534:Trans-Activators; D020744:rac GTP-Binding Proteins
C090145:Cdc42 protein, Drosophila; D029721:Drosophila Proteins; D019476:Insect Proteins; C090146:Rac1 protein, Drosophila; D012097:Repressor Proteins; D015534:Trans-Activators; C064196:dpp protein, Drosophila; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; C117694:Hep protein, Drosophila; D020929:Mitogen-Activated Protein Kinase Kinases; D019204:GTP-Binding Proteins; D020744:rac GTP-Binding Proteins