The adhesion molecule TAG-1 mediates the migration of cortical interneurons from the ganglionic eminence along the corticofugal fiber system.
Cortical nonpyramidal cells, the GABA-containing interneurons, originate mostly in the medial ganglionic eminence of the ventral telencephalon and follow tangential migratory routes to reach the dorsal telencephalon. Although several genes that play a role in this migration have been identified, the underlying cellular and molecular cues are not fully understood. We provide evidence that the neural cell adhesion molecule TAG-1 mediates the migration of cortical interneurons. We show that the migration of these neurons occurs along the TAG-1-expressing axons of the developing corticofugal system. The spatial and temporal pattern of expression of TAG-1 on corticofugal fibers coincides with the order of appearance of GABAergic cells in the developing cortex. Blocking the function of TAG-1, but not of L1, another adhesion molecule and binding partner of TAG-1, results in a marked reduction of GABAergic neurons in the cortex. These observations reveal a mechanism by which the adhesion molecule TAG-1, known to be involved in axonal pathfinding, also takes part in neuronal migration.
Denaxa
M
M
Department of Basic Science, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, PO Box 1527, 711 10 Heraklion, Greece.
Chan
C H
CH
Schachner
M
M
Parnavelas
J G
JG
Karagogeos
D
D
D000818:Animals; D001921:Brain / Q000196:embryology*; D015816:Cell Adhesion Molecules, Neuronal / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D002465:Cell Movement; D002540:Cerebral Cortex / Q000166:cytology / Q000196:embryology*; D058969:Contactin 2; D004525:Efferent Pathways; D007395:Interneurons / Q000502:physiology*; D039841:Leukocyte L1 Antigen Complex; D008562:Membrane Glycoproteins / Q000302:isolation & purification / Q000378:metabolism; D051379:Mice; D008959:Models, Neurological; D009412:Nerve Fibers; D019006:Neural Cell Adhesion Molecules / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013788:Thalamus / Q000166:cytology; D005680:gamma-Aminobutyric Acid
D015816:Cell Adhesion Molecules, Neuronal; C548675:Cntn2 protein, mouse; D058969:Contactin 2; D039841:Leukocyte L1 Antigen Complex; D008562:Membrane Glycoproteins; D019006:Neural Cell Adhesion Molecules; D005680:gamma-Aminobutyric Acid