Protein Helps Wire Up Circuitry Controlling Muscle

A recently published study described how the signaling protein WNT-3 directs specific neurons during embryonic development to make the correct connections in the spine to form a neural pathway that controls muscle. The study appeared in the September 2002 issue of Neuron.

Researchers from Imperial College London (UK) and King's College London (UK) working with mice found that WNT-3 is only produced by motor neurons in the spinal cord at a crucial stage when sensory neurons come close to them.

"Assembling the components to connect any neural circuit is a complex process. During development of the brain and spinal cord a hundred million neurons are looking for their neural partners to make connections with,” said study leader Dr. Patricia Salinas of Imperial College's department of biological sciences. "We found that motor neurons release the WNT-3 protein to guide sensory neurons to make connections with them.”

Tissue culture studies employing spinal tissue from embryonic mice revealed that, in response to the WNT-3 signal, sensory neurons stopped growing and began to branch prior to forming synaptic connections.

"The molecular identities of signals that regulate formation of specific connections between sensory and motor neurons were previously unknown. Understanding the complex web of instructions that direct this intricate process may have important implications for neural regeneration following spinal injury,” said Dr Salinas.





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Imperial College London
King's College London