EGF signaling and ommatidial rotation in the Drosophila eye

Curr Biol. 2003 Aug 19;13(16):1451-7. doi: 10.1016/s0960-9822(03)00545-1.

Abstract

The ommatidia of the Drosophila eye initiate development by stepwise recruitment of photoreceptors into symmetric ommatidial clusters. As they mature, the clusters become asymmetric, adopting opposite chirality on either side of the dorsoventral midline and rotating exactly 90 degrees (Figures 1A and 1B, ). The choice of chirality is governed by higher activity of the frizzled (fz) gene in one cell of the R3/R4 photoreceptor pair and by Notch-Delta (N-Dl) signaling. The 90 degrees rotation also requires activity of planar polarity genes such as fz as well as the roulette (rlt) locus. We now show that two regulators of EGF signaling, argos and sprouty (sty), and a gain-of-function Ras85D allele, interact genetically with fz in ommatidial polarity. Furthermore, we find that argos is required for ommatidial rotation, but not chirality, and that rlt is a novel allele of argos. We present evidence that there are two pathways by which EGF signaling affects ommatidial rotation. In the first, typified by the rlt phenotype, there is partial transformation of the "mystery cells" toward a neuronal fate. Although most of these mystery cells subsequently fail to develop as neurons, their partial transformation results in inappropriate subcellular localization of the Fz receptor, a likely cue for regulating ommatidial rotation. Secondly, reducing EGF signaling can specifically affect ommatidial rotation without showing transformation of the mystery cells or defects in polarity protein localization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Body Patterning
  • Drosophila / genetics
  • Drosophila / growth & development*
  • Drosophila / metabolism*
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism
  • Epidermal Growth Factor / metabolism*
  • Eye / growth & development*
  • Eye Proteins / genetics
  • Eye Proteins / metabolism
  • Frizzled Receptors
  • Genes, Insect
  • Green Fluorescent Proteins
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mutation
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Phenotype
  • Photoreceptor Cells, Invertebrate / growth & development
  • Photoreceptor Cells, Invertebrate / metabolism
  • Receptors, G-Protein-Coupled
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Signal Transduction

Substances

  • Drosophila Proteins
  • Eye Proteins
  • Frizzled Receptors
  • Luminescent Proteins
  • Membrane Proteins
  • Nerve Tissue Proteins
  • Receptors, G-Protein-Coupled
  • Recombinant Fusion Proteins
  • fz protein, Drosophila
  • sty protein, Drosophila
  • Green Fluorescent Proteins
  • aos protein, Drosophila
  • Epidermal Growth Factor