title: WNT-3, expressed by motoneurons, regulates terminal arborization of neurotrophin-3-responsive spinal sensory neurons.
abstract: Sensory axons from dorsal root ganglia neurons are guided to spinal targets by molecules differentially expressed along the dorso-ventral axis of the neural tube. NT-3-responsive muscle afferents project ventrally, cease extending, and branch upon contact with motoneurons (MNs), their synaptic partners. We have identified WNT-3 as a candidate molecule that regulates this process. Wnt-3 is expressed by MNs of the lateral motor column at the time when MNs form synapses with sensory neurons. WNT-3 increases branching and growth cone size while inhibiting axonal extension in NT-3- but not NGF-responsive axons. Ventral spinal cord secretes factors with axonal remodeling activity for NT-3-responsive neurons. This activity is present at limb levels and is blocked by a WNT antagonist. We propose that WNT-3, expressed by MNs, acts as a retrograde signal that controls terminal arborization of muscle afferents.
mesh_terms: D000344:Afferent Pathways / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D005727:Ganglia, Spinal / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3; D006023:Glycoproteins / Q000378:metabolism / Q000494:pharmacology; D020439:Growth Cones / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D009046:Motor Neurons / Q000166:cytology / Q000378:metabolism*; D020932:Nerve Growth Factor / Q000378:metabolism / Q000494:pharmacology; D009434:Neural Pathways / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D009473:Neuronal Plasticity / Q000187:drug effects / Q000235:genetics; D009475:Neurons, Afferent / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D020933:Neurotrophin 3 / Q000378:metabolism* / Q000494:pharmacology; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D011506:Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013116:Spinal Cord / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D051153:Wnt Proteins; D060508:Wnt3 Protein; D000099274:Frizzled-Related Proteins
chemical_list: D017871:Calcium-Calmodulin-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3; D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D020932:Nerve Growth Factor; D020933:Neurotrophin 3; D011506:Proteins; D051153:Wnt Proteins; D060508:Wnt3 Protein; D000099274:Frizzled-Related Proteins; C555508:Wnt3 protein, mouse