Glial and neuronal Semaphorin signaling instruct the development of a functional myotopic map for Drosophila walking

Elife. 2016 Feb 29:5:e11572. doi: 10.7554/eLife.11572.


Motoneurons developmentally acquire appropriate cellular architectures that ensure connections with postsynaptic muscles and presynaptic neurons. In Drosophila, leg motoneurons are organized as a myotopic map, where their dendritic domains represent the muscle field. Here, we investigate mechanisms underlying development of aspects of this myotopic map, required for walking. A behavioral screen identified roles for Semaphorins (Sema) and Plexins (Plex) in walking behavior. Deciphering this phenotype, we show that PlexA/Sema1a mediates motoneuron axon branching in ways that differ in the proximal femur and distal tibia, based on motoneuronal birth order. Importantly, we show a novel role for glia in positioning dendrites of specific motoneurons; PlexB/Sema2a is required for dendritic positioning of late-born motoneurons but not early-born motoneurons. These findings indicate that communication within motoneurons and between glia and motoneurons, mediated by the combined action of different Plexin/Semaphorin signaling systems, are required for the formation of a functional myotopic map.

Keywords: d. melanogaster; developmental biology; glia; motor neurons; myotopic map; neuron targeting; neuroscience; semaphorin; stem cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Drosophila / embryology*
  • Drosophila Proteins / metabolism
  • Motor Neurons / physiology*
  • Nerve Tissue Proteins / metabolism
  • Neuroglia / physiology*
  • Receptors, Cell Surface / metabolism
  • Semaphorins / metabolism*
  • Signal Transduction*
  • Walking


  • Drosophila Proteins
  • Nerve Tissue Proteins
  • Receptors, Cell Surface
  • Semaphorins
  • plexA protein, Drosophila
  • semaphorin 1a, Drosophila

Grants and funding

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.