Identification of a neuregulin and protein-tyrosine phosphatase response element in the nicotinic acetylcholine receptor epsilon subunit gene: regulatory role of an Rts transcription factor

Proc Natl Acad Sci U S A. 1998 Feb 3;95(3):1289-94. doi: 10.1073/pnas.95.3.1289.

Abstract

At the neuromuscular synapse, innervation induces endplate-specific expression of adult-type nicotinic acetylcholine receptors by selective expression of their subunit-encoding genes (alpha2betaepsilondelta) in endplate-associated myonuclei. These genes are specifically regulated by protein-tyrosine phosphatase (PTPase) activity. In addition, neuregulin/acetylcholine-receptor-inducing activity, a nerve-derived factor that stimulates nicotinic acetylcholine receptor synthesis, induces adult-type specific epsilon subunit gene expression via activation of a Ras/mitogen-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 epsilon subunit gene map to a 15-bp promoter sequence. Interestingly, this same 15-bp sequence appears to be necessary for low epsilon 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 sequence-specific induction of epsilon subunit promoter activity. Further, a dominant negative mutant of Ets-2 abolished neuregulin-dependent induction of epsilon 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 epsilon subunit gene expression and suggest the participation of Ets transcription factor(s) in this control.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cells, Cultured
  • DNA / metabolism
  • DNA-Binding Proteins*
  • Gene Expression Regulation*
  • Glycoproteins / physiology*
  • Motor Neurons / physiology*
  • Neuregulins
  • Promoter Regions, Genetic
  • Protein Tyrosine Phosphatases / physiology*
  • Protein-Tyrosine Kinases / genetics
  • Protein-Tyrosine Kinases / metabolism
  • Proto-Oncogene Protein c-ets-2
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism
  • Proto-Oncogene Proteins / physiology*
  • Rats
  • Receptors, Nicotinic / genetics*
  • Repressor Proteins*
  • Trans-Activators / genetics
  • Trans-Activators / metabolism
  • Trans-Activators / physiology*
  • Transcription Factors*
  • Transfection
  • ras Proteins / physiology

Substances

  • DNA-Binding Proteins
  • ERF protein, human
  • Ets2 protein, rat
  • Glycoproteins
  • Neuregulins
  • Proto-Oncogene Protein c-ets-2
  • Proto-Oncogene Proteins
  • Receptors, Nicotinic
  • Repressor Proteins
  • Trans-Activators
  • Transcription Factors
  • DNA
  • Protein-Tyrosine Kinases
  • Protein Tyrosine Phosphatases
  • ras Proteins