1. Developmental Biology
  2. Neuroscience
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Birth order dependent growth cone segregation determines synaptic layer identity in the Drosophila visual system

  1. Abhishek Kulkarni
  2. Deniz Ertekin
  3. Chi-Hon Lee
  4. Thomas Hummel  Is a corresponding author
  1. University of Vienna, Austria
  2. Eunice Kennedy Shriver National Institute of Child Health and Human Development, United States
Research Article
  • Cited 24
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Cite this article as: eLife 2016;5:e13715 doi: 10.7554/eLife.13715

Abstract

The precise recognition of appropriate synaptic partner neurons is a critical step during neural circuit assembly. However, little is known about the developmental context in which recognition specificity is important to establish synaptic contacts. We show that in the Drosophila visual system, sequential segregation of photoreceptor afferents, reflecting their birth order, lead to differential positioning of their growth cones in the early target region. By combining loss- and gain-of-function analyses we demonstrate that relative differences in the expression of the transcription factor Sequoia regulate R cell growth cone segregation. This initial growth cone positioning is consolidated via cell-adhesion molecule Capricious in R8 axons. Further, we show that the initial growth cone positioning determines synaptic layer selection through proximity-based axon-target interactions. Taken together, we demonstrate that birth order dependent pre-patterning of afferent growth cones is an essential pre-requisite for the identification of synaptic partner neurons during visual map formation in Drosophila.

Article and author information

Author details

  1. Abhishek Kulkarni

    Department of Neurobiology, University of Vienna, Vienna, Austria
    Competing interests
    The authors declare that no competing interests exist.
  2. Deniz Ertekin

    Department of Neurobiology, University of Vienna, Vienna, Austria
    Competing interests
    The authors declare that no competing interests exist.
  3. Chi-Hon Lee

    Section on Neuronal Connectivity, Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Thomas Hummel

    Department of Neurobiology, University of Vienna, Vienna, Austria
    For correspondence
    thomas.hummel@univie.ac.at
    Competing interests
    The authors declare that no competing interests exist.

Reviewing Editor

  1. Alexander Borst, Max Planck Institute of Neurobiology, Germany

Publication history

  1. Received: December 10, 2015
  2. Accepted: March 16, 2016
  3. Accepted Manuscript published: March 17, 2016 (version 1)
  4. Version of Record published: April 21, 2016 (version 2)

Copyright

© 2016, Kulkarni et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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