title: Orthodenticle regulation during embryonic head development in Drosophila.
abstract: The homeobox gene orthodenticle (otd) specifies anterior head development in the Drosophila embryo, otd-related genes are also found in vertebrates, with expression patterns suggesting that they are important for the development of anterior regions of the head and brain. Here, we analyze the molecular mechanisms by which otd expression is activated within its normal domain in the head and repressed outside this region. We demonstrate that, contrary to early models of embryonic pattern formation, high levels of the bicoid morphogen are not required for otd activation or for the establishment of anterior head structures. We also show that the terminal system contributes to otd activation in the head primordium. Finally, we identify a novel pathway mediated by the gap gene huckebein through which three maternal systems cooperate to repress otd expression at the anterior terminus of the embryo.
authors.affiliation: University of Pennsylvania School of Medicine, Department of Neuroscience, Philadelphia, PA 19104, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Gao
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: R
authors.initials: R
authors.lastname: Finkelstein
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000502:physiology; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics; D047108:Embryonic Development; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D006257:Head / Q000196:embryology; D018398:Homeodomain Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D007301:Insect Hormones / Q000502:physiology; D009024:Morphogenesis / Q000235:genetics; D009687:Nuclear Proteins / Q000502:physiology; D010750:Phosphoproteins / Q000502:physiology; D020794:Receptor Protein-Tyrosine Kinases / Q000502:physiology; D015534:Trans-Activators; D014157:Transcription Factors / Q000502:physiology
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C087725:Hkb protein, Drosophila; D018398:Homeodomain Proteins; D007301:Insect Hormones; D009687:Nuclear Proteins; D010750:Phosphoproteins; D015534:Trans-Activators; D014157:Transcription Factors; C056478:bcd protein, Drosophila; C062236:dl protein, Drosophila; C061245:hb protein, Drosophila; C093053:oc protein, Drosophila; D020794:Receptor Protein-Tyrosine Kinases; C080148:tor protein, Drosophila