Transcriptional repression of the α7 nicotinic acetylcholine receptor subunit gene (CHRNA7) by activating protein-2α (AP-2α)

J Biol Chem. 2011 Dec 9;286(49):42123-42132. doi: 10.1074/jbc.M111.276014. Epub 2011 Oct 6.

Abstract

The CHRNA7 gene, which encodes the α7 nicotinic acetylcholine receptor (α7*nAChR), has been implicated as a candidate gene in schizophrenia. Expression of the α7*nAChR mRNA and protein are reduced in multiple regions of post-mortem brain from patients diagnosed with schizophrenia. Transcriptional regulation may therefore be an important mechanism for the regulation of this gene. A 230-bp proximal promoter fragment, necessary for transcription in cultured neuroblastoma cells, was used to study a putative AP-2α binding site. Mutation of the site indicates that AP-2α plays a negative role in regulating CHRNA7 transcription. This was confirmed through knockdown and overexpression of AP-2α. Electrophoretic mobility shift assays (EMSAs) identified positive DNA-protein interaction at this same site, and supershift assays indicate that the complex includes AP-2α. The interaction was confirmed in cells using chromatin immunoprecipitation (ChIP). DNA methylation was discovered as an anomalous mechanism for CHRNA7 regulation in one cell line. These studies suggest a role for AP-2α regulation of CHRNA7 mRNA expression in multiple tissues during development.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Cell Line, Tumor
  • DNA Methylation
  • Gene Expression Regulation*
  • Genetic Vectors
  • HeLa Cells
  • Humans
  • Mutagenesis, Site-Directed
  • Mutation
  • Promoter Regions, Genetic
  • RNA, Messenger / metabolism
  • RNA, Small Interfering / metabolism
  • Receptors, Nicotinic / biosynthesis*
  • Receptors, Nicotinic / metabolism
  • Schizophrenia / genetics*
  • Transcription Factor AP-2 / metabolism*
  • Transcription, Genetic
  • alpha7 Nicotinic Acetylcholine Receptor

Substances

  • Chrna7 protein, human
  • RNA, Messenger
  • RNA, Small Interfering
  • Receptors, Nicotinic
  • Transcription Factor AP-2
  • alpha7 Nicotinic Acetylcholine Receptor