Glial cells mediate target layer selection of retinal axons in the developing visual system of Drosophila

Neuron. 2001 Jan;29(1):99-113. doi: 10.1016/s0896-6273(01)00183-0.


In the fly visual system, each class of photoreceptor neurons (R cells) projects to a different synaptic layer in the brain. R1-R6 axons terminate in the lamina, while R7 and R8 axons pass through the lamina and stop in the medulla. As R cell axons enter the lamina, they encounter both glial cells and neurons. The cellular requirement for R1-R6 targeting was determined using loss-of-function mutations affecting different cell types in the lamina. nonstop (encoding a ubiquitin-specific protease) is required for glial cell development and hedgehog for neuronal development. Removal of glial cells but not neurons disrupts R1-R6 targeting. We propose that glial cells provide the initial stop signal promoting growth cone termination in the lamina. These findings uncover a novel function for neuron-glial interactions in regulating target specificity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Axons / metabolism*
  • Cell Movement / genetics
  • Drosophila
  • Drosophila Proteins*
  • Endopeptidases / genetics
  • Endopeptidases / metabolism*
  • Eye / cytology
  • Eye / growth & development*
  • Growth Cones
  • Insect Proteins / genetics
  • Insect Proteins / metabolism
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Neuroglia / cytology
  • Neuroglia / metabolism*
  • Neurons / cytology
  • Neurons / metabolism
  • Photoreceptor Cells, Invertebrate / cytology
  • Retina / cytology
  • Retina / growth & development
  • Retina / metabolism*
  • Stem Cells / cytology
  • Stem Cells / metabolism
  • Ubiquitins / metabolism


  • Drosophila Proteins
  • Insect Proteins
  • Ubiquitins
  • Endopeptidases
  • not protein, Drosophila

Associated data

  • GENBANK/AF179590