At the neuromuscular synapse, innervation induces endplate-specific expression of adult-type nicotinic acetylcholine receptors by selective expression of their subunit-encoding genes (␣ 2 ␤␦) in endplate-associated myonuclei. These genes are specifically regulated by protein-tyrosine phosphatase (PTPase) activity. In addition, neuregulin͞ acetylcholine-receptor-inducing activity, a nerve-derived factor that stimulates nicotinic acetylcholine receptor synthesis, induces adult-type specific subunit gene expression via activation of a Ras͞mitogen-activated protein kinase pathway. However, the DNA regulatory elements and the binding proteins that mediate PTPase and neuregulin-dependent gene expression remain unknown. Herein we report that PTPase, neuregulin, and Ras-dependent regulation of the subunit gene map to a 15-bp promoter sequence. Interestingly, this same 15-bp sequence appears to be necessary for low subunit gene expression in extrajunctional regions of the muscle fiber. Site-directed mutagenesis of a putative Ets binding site located within this 15-bp sequence, reduced PTPase, neuregulin, and Ras-dependent regulation. Overexpression of the rat muscle Ets-2 transcription factor resulted in a sequencespecific induction of subunit promoter activity. Further, a dominant negative mutant of Ets-2 abolished neuregulindependent induction of subunit gene expression. Thus, these results indicate a crucial role for the 15-bp element in determining synapse-specific and neuregulin-mediated motor neuron control of subunit gene expression and suggest the participation of Ets transcription factor(s) in this control.