Motor Neuron Position and Topographic Order Imposed by β- and γ-Catenin Activities

SummaryNeurons typically settle at positions that match the location of their synaptic targets, creating topographic maps. In the spinal cord, the organization of motor neurons into discrete clusters is linked to the location of their muscle targets, establishing a topographic map of punctate design. To define the significance of motor pool organization for neuromuscular map formation, we assessed the role of cadherin-catenin signaling in motor neuron positioning and limb muscle innervation. We find that joint inactivation of β- and γ-catenin scrambles motor neuron settling position in the spinal cord but fails to erode the predictive link between motor neuron transcriptional identity and muscle target. Inactivation of N-cadherin perturbs pool positioning in similar ways, albeit with reduced penetrance. These findings reveal that cadherin-catenin signaling directs motor pool patterning and imposes topographic order on an underlying identity-based neural map.PaperClip To listen to this audio, enable JavaScript on your browser. However, you can download and play the audio by clicking on the icon belowHelp with MP3 filesOptionsDownload audio (3757 K)

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► β- and γ-catenin activities control motor neuron positioning
► β- and γ-catenin activities ensure topographic order in neuromuscular maps
► β- and γ-catenin control the somatodendritic differentiation of motor neurons
► β- and γ-catenin transduce classical cadherin signals in motor neurons