Axonin-1, Nr-CAM, and Ng-CAM play different roles in the in vivo guidance of chick commissural neurons.
Immunoglobulin/fibronectin type III-like cell adhesion molecules have been implicated in axon pathfinding based on their expression pattern in the developing nervous system and on their complex interactions described in vitro. The present in vivo study demonstrates that interactions by two of these molecules, axonin-1 on commissural growth cones and Nr-CAM on floor plate cells, are required for accurate pathfinding at the midline. When axonin-1 or Nr-CAM interactions were perturbed, many commissural axons failed to cross the midline and turned instead along the ipsilateral floor plate border. In contrast, though perturbation of Ng-CAM produced a defasciculation of the commissural neurites, it did not affect their guidance across the floor plate.
Stoeckli
E T
ET
Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio 44106-4975, USA.
Landmesser
L T
LT
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001369:Axons / Q000502:physiology* / Q000648:ultrastructure; D015815:Cell Adhesion Molecules; D015816:Cell Adhesion Molecules, Neuronal / Q000502:physiology*; D002642:Chick Embryo; D058969:Contactin 2; D016326:Extracellular Matrix Proteins / Q000502:physiology*; D008856:Microscopy, Fluorescence; D016501:Neurites / Q000502:physiology / Q000648:ultrastructure; D009474:Neurons / Q000648:ultrastructure*; D013116:Spinal Cord / Q000196:embryology / Q000648:ultrastructure; D019063:Tenascin
D000906:Antibodies; C548674:CNTN2 protein, human; D015815:Cell Adhesion Molecules; D015816:Cell Adhesion Molecules, Neuronal; D058969:Contactin 2; D016326:Extracellular Matrix Proteins; C491152:NRCAM protein, human; D019063:Tenascin