Synapse-specific gene expression

Inductive interactions between motor neuron and muscle result in the formation of synaptic structures at the neuromuscular junction. The localized appearance of synaptic proteins is due in part to the selective expression of specific genes in the muscle nuclei which lie beneath the motor endplate. For example, synapse-specific expression of the acetylcholine receptor subunit genes contributes to the restricted distribution of the acetylcholine receptor. A transynaptic, motor neuron-derived signal is thought to induce changes in the transcriptional potential of synaptic nuclei. Although the precise mechanisms of gene activation have yet to be elucidated, a neuronally derived factor called ARIA is likely to play a central role in this process.