title: Differential regulation of Ultrabithorax in two germ layers of Drosophila.
abstract: The homeotic gene Ultrabithorax (Ubx) is expressed in specific parts of Drosophila embryos: in a single metamer in the visceral mesoderm and forming a complex pattern limited to a broad domain in the ectoderm and in the somatic mesoderm. Here we use a linked beta-galactosidase gene to identify cis-acting regulatory sequences. In the visceral mesoderm, correct expression of Ubx depends on localized upstream sequences. In the ectoderm, all galactosidase-positive transformants show the same characteristic pattern. The repeated elements of this basal pattern appear to be a sub-pattern of engrailed (en) expression; they depend on en function as well as on sequences in the Ubx RNA leader. We use a mutant (Haltere-mimic) to show that sequences that normally restrict segmental expression of Ubx in the ectoderm are located downstream from the RNA leader.
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D004330:Drosophila / Q000196:embryology / Q000235:genetics*; D004475:Ectoderm; D005786:Gene Expression Regulation; D005801:Genes, Homeobox; D008648:Mesoderm; D009154:Mutation; D010641:Phenotype; D011401:Promoter Regions, Genetic; D021382:Protein Sorting Signals / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D014170:Transformation, Genetic
chemical_list: D021382:Protein Sorting Signals; D012333:RNA, Messenger