Departments of Cell Biology and Pharmacology (Skirball)Skirball Institute Program of Molecular Neurobiology

AChR subunit genes are transcribed selectively in nuclei in the synaptic region of the myofiber, resulting in accumulation of AChR mRNA at synaptic sites. There is evidence that the extracellular signal, which is contained in the synaptic basal lamina and which triggers synapse-specific gene expression, is neuregulin. This model predicts that activation of neuregulin receptors, erbB3 and erbB4, which are concentrated at synapses, stimulates AChR gene expression in nuclei near the activated receptors.