Inhibitory effects of draxin on axonal outgrowth and migration of precerebellar neurons.
The rhombic lip, a dorsal stripe of the neuroepithelium lining the edge of the fourth ventricle, is the site of origin of precerebellar neurons (PCN), which migrate tangentially towards the floor plate. After reaching the floor plate, they project their axons to the cerebellum. Although previous studies have shown that the guidance molecules Netrin/DCC and Slit/Robo have critical roles in PCN migration, the molecular mechanisms underlying this process remain poorly understood. Here, we report that draxin, a repulsive axon guidance protein, is involved in PCN development. We found that draxin is expressed in the rhombic lip and migratory stream of some PCN in the developing hindbrain of mice. In addition, draxin inhibited neurite outgrowth and nuclei migration from rhombic lip explants. These results suggest that draxin functions as a repulsive guidance cue for PCN migration. However, we observed no significant differences in PCN distribution between draxin(-/-) and wild type embryos. Thus, draxin and other axon guidance cues may have redundant roles in PCN migration.
Division of Developmental Neurobiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan; Stem Cell-Based Tissue Regeneration Research and Education Unit, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-0811, Japan.
M Asrafuzzaman
MA
Riyadh
Division of Developmental Neurobiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan. Electronic address: shinmyo@med.kanazawa-u.ac.jp.
Yohei
Y
Shinmyo
Division of Developmental Neurobiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
Kunimasa
K
Ohta
Division of Developmental Neurobiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan.
Hideaki
H
Tanaka
D000818:Animals; D001369:Axons / Q000502:physiology* / Q000648:ultrastructure*; D049108:Cell Enlargement; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D002531:Cerebellum / Q000196:embryology* / Q000502:physiology*; D036341:Intercellular Signaling Peptides and Proteins / Q000502:physiology*; D051379:Mice; D018345:Mice, Knockout; D009474:Neurons / Q000166:cytology* / Q000502:physiology*
D036341:Intercellular Signaling Peptides and Proteins; C534831:draxin protein, mouse
Axon outgrowth; Draxin; Migration; Precerebellar neurons