Transient neuronal populations are required to guide callosal axons: a role for semaphorin 3C.
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.
Niquille
Mathieu
M
Department of Cellular Biology and Morphology, University of Lausanne, Switzerland.
Garel
Sonia
S
Mann
Fanny
F
Hornung
Jean-Pierre
JP
Otsmane
Belkacem
B
Chevalley
Sébastien
S
Parras
Carlos
C
Guillemot
Francois
F
Gaspar
Patricia
P
Yanagawa
Yuchio
Y
Lebrand
Cécile
C
D055673:Acrocallosal Syndrome / Q000378:metabolism / Q000473:pathology; D000818:Animals; D001369:Axons / Q000378:metabolism* / Q000473:pathology; D002460:Cell Line; D002465:Cell Movement; D018920:Coculture Techniques; D003337:Corpus Callosum / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D006801:Humans; D051379:Mice; D009434:Neural Pathways / Q000166:cytology / Q000196:embryology; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D039942:Neuropilin-1 / Q000378:metabolism; D039961:Semaphorins / Q000378:metabolism*
D039961:Semaphorins; C510203:semaphorin 3C protein, mouse; D039942:Neuropilin-1