Mechanisms of glial-guided neuronal migration in vitro and in vivo.
Our laboratory has developed an in vitro model system in which glial-guided neuronal migration can be observed in real time. Cerebellar granule neurons migrate on astroglial fibers by apposing their cell soma against the glial arm, forming a specialized migration junction, and extending a motile leading process in the direction of migration. In vitro assays indicate that the neuronal antigen astrotactin functions as a neuron-glia ligand, and is likely to play a role in the movement of neurons along glial fibers. In heterotypic recombinations of neurons and glia from mouse cerebellum and rat hippocampus, neurons migrate on heterotypic glial processes with a cytology, speed and mode of movement identical to that of neuronal migration on homotypic glial fibers, suggesting that glial fibers provide a permissive pathway for neuronal migration in developing brain. In vivo analyses of developing cerebellum demonstrate a close coordination of afferent axon ingrowth relative to target cell migration. These studies indicate that climbing fibers contact immature Purkinje neurons during the migration and settling of Purkinje cells, implicating a role for afferents in the termination of migration.
Hatten
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ME
Department of Pathology, College of Physicians and Surgeons of Columbia University, New York, New York 10032.
Mason
C A
CA
D000818:Animals; D001369:Axons / Q000502:physiology; D002465:Cell Movement; D002531:Cerebellum / Q000166:cytology; D006023:Glycoproteins / Q000502:physiology; D006624:Hippocampus / Q000166:cytology; D051379:Mice; D008818:Mice, Neurologic Mutants; D009419:Nerve Tissue Proteins / Q000502:physiology; D009457:Neuroglia / Q000502:physiology*; D009474:Neurons / Q000166:cytology*
C072976:Astn1 protein, mouse; D006023:Glycoproteins; D009419:Nerve Tissue Proteins