Transient neuronal populations are required to guide callosal axons: a role for semaphorin 3C

PLoS Biol. 2009 Oct;7(10):e1000230. doi: 10.1371/journal.pbio.1000230. Epub 2009 Oct 27.


The corpus callosum (CC) is the main pathway responsible for interhemispheric communication. CC agenesis is associated with numerous human pathologies, suggesting that a range of developmental defects can result in abnormalities in this structure. Midline glial cells are known to play a role in CC development, but we here show that two transient populations of midline neurons also make major contributions to the formation of this commissure. We report that these two neuronal populations enter the CC midline prior to the arrival of callosal pioneer axons. Using a combination of mutant analysis and in vitro assays, we demonstrate that CC neurons are necessary for normal callosal axon navigation. They exert an attractive influence on callosal axons, in part via Semaphorin 3C and its receptor Neuropilin-1. By revealing a novel and essential role for these neuronal populations in the pathfinding of a major cerebral commissure, our study brings new perspectives to pathophysiological mechanisms altering CC formation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrocallosal Syndrome / metabolism
  • Acrocallosal Syndrome / pathology
  • Animals
  • Axons / metabolism*
  • Axons / pathology
  • Cell Line
  • Cell Movement
  • Coculture Techniques
  • Corpus Callosum / cytology
  • Corpus Callosum / embryology*
  • Corpus Callosum / metabolism
  • Humans
  • Mice
  • Neural Pathways / cytology
  • Neural Pathways / embryology
  • Neurons / cytology
  • Neurons / metabolism*
  • Neuropilin-1 / metabolism
  • Semaphorins / metabolism*


  • Semaphorins
  • semaphorin 3C protein, mouse
  • Neuropilin-1