Drosophila endoderm development requires a novel homeobox gene which is a target of Wingless and Dpp signalling.
We have identified and cloned a novel type of homeobox gene that is composed of two homeodomains and is expressed in the Drosophila endoderm. Mutant analysis reveals that its activity is required at the foregut/midgut boundary for the development of the proventriculus. This organ regulates food passage from the foregut into the midgut and forms by the infolding of ectoderm and endoderm-derived tissues. The endodermal outer wall structure of the proventriculus is collapsed in the mutants leading to a failure of the ectodermal part to invaginate and build a functional multilayered organ. Lack-of-function and gain-of-function experiments show that the expression of this homeobox gene in the proventriculus endoderm is induced in response to Wingless activity emanating from the ectoderm/endoderm boundary whereas its expression in the central midgut is controlled by Dpp and Wingless signalling emanating from the overlying visceral mesoderm.
Fuss
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B
Max-Planck-Institut für biophysikalische Chemie, Abt. Molekulare Entwicklungsbiologie, Göttingen, Germany.
Hoch
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D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D004064:Digestive System / Q000196:embryology / Q000378:metabolism; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian; D004707:Endoderm / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D008648:Mesoderm / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D011531:Proventriculus / Q000166:cytology / Q000196:embryology; D015398:Signal Transduction; D014158:Transcription, Genetic; D051155:Wnt1 Protein
D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D019476:Insect Proteins; D011518:Proto-Oncogene Proteins; D051155:Wnt1 Protein; C064196:dpp protein, Drosophila; C114494:dve protein, Drosophila; C074622:wg protein, Drosophila