Regulation of EGF receptor signaling establishes pattern across the developing Drosophila retina.
Developing epithelia use a variety of patterning mechanisms to place individual cells into their correct positions. However, the means by which pattern elements are established are poorly understood. Here, we report evidence that regulation of Drosophila EGF receptor (DER) activity plays a central role in propagating the evenly spaced array of ommatidia across the developing Drosophila retina. DER activity is essential for establishing the first ommatidial cell fate, the R8 photoreceptor neuron. R8s in turn appear to signal through Rhomboid and Vein to create a patterned array of 'proneural clusters' which contain high levels of phosphorylated ERKA and the bHLH protein Atonal. Finally, secretion by the proneural clusters of Argos represses DER activity in less mature regions to create a new pattern of R8s. Propagation of this process anteriorly results in a retina with a precise array of maturing ommatidia.
Spencer
S A
SA
Department of Molecular Biology and Pharmacology, Washington University School of Medicine, Campus Box 8103, St. Louis, Mo 63110, USA.
Powell
P A
PA
Miller
D T
DT
Cagan
R L
RL
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D019521:Body Patterning / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics / Q000528:radiation effects; D004625:Embryo, Nonmammalian / Q000502:physiology; D066246:ErbB Receptors / Q000235:genetics* / Q000502:physiology; D005720:Gamma Rays; D018507:Gene Expression Regulation, Developmental; D011905:Genes, ras; D018257:Helix-Loop-Helix Motifs; D019476:Insect Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008938:Mitosis; D016296:Mutagenesis; D020880:Neuregulins; D010766:Phosphorylation; D010786:Photoreceptor Cells / Q000166:cytology / Q000196:embryology; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000196:embryology*; D011995:Recombination, Genetic; D012160:Retina / Q000166:cytology / Q000196:embryology*; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism
D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D066246:ErbB Receptors; D019476:Insect Proteins; D008565:Membrane Proteins; D020880:Neuregulins; D014157:Transcription Factors; C081481:Rho protein, Drosophila; C472498:Stet protein, Drosophila; C102104:vn protein, Drosophila