Compartments and organising boundaries in the Drosophila eye: the role of the homeodomain Iroquois proteins.
The Drosophila eye is patterned by a dorsal-ventral organising centre mechanistically similar to those in the fly wing and the vertebrate limb bud. Here we show how this organising centre in the eye is initiated - the first event in retinal patterning. Early in development the eye primordium is divided into dorsal and ventral compartments. The dorsally expressed homeodomain Iroquois genes are true selector genes for the dorsal compartment; their expression is regulated by Hedgehog and Wingless. The organising centre is then induced at the interface between the Iroquois-expressing and non-expressing cells at the eye midline. It was previously thought that the eye develops by a mechanism distinct from that operating in other imaginal discs, but our work establishes the importance of lineage compartments in the eye and thus supports their global role as fundamental units of patterning.
Cavodeassi
F
F
Centro de Biología Molecular Severo Ochoa, CSIC and UAM, Spain.
Diez Del Corral
R
R
Campuzano
S
S
Domínguez
M
M
D000818:Animals; D004330:Drosophila / Q000196:embryology* / Q000235:genetics / Q000254:growth & development; D029721:Drosophila Proteins; D015870:Gene Expression; D053823:Hedgehog Proteins; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D019476:Insect Proteins / Q000378:metabolism / Q000502:physiology; D008565:Membrane Proteins / Q000378:metabolism; D017351:N-Acetylglucosaminyltransferases; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology; D020897:Organizers, Embryonic; D010750:Phosphoproteins / Q000235:genetics / Q000502:physiology; D017956:Photoreceptor Cells, Invertebrate / Q000196:embryology; D011518:Proto-Oncogene Proteins / Q000502:physiology; D051880:Receptors, Notch; D014018:Tissue Distribution; D014157:Transcription Factors; D051155:Wnt1 Protein
D029721:Drosophila Proteins; D053823:Hedgehog Proteins; D018398:Homeodomain Proteins; D019476:Insect Proteins; D008565:Membrane Proteins; C497759:N protein, Drosophila; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D051880:Receptors, Notch; D014157:Transcription Factors; D051155:Wnt1 Protein; C062236:dl protein, Drosophila; C074622:wg protein, Drosophila; C077245:hh protein, Drosophila; D017351:N-Acetylglucosaminyltransferases; C090576:fng protein, Drosophila