title: Promoter methylation and tissue-specific transcription of the α7 nicotinic receptor gene, CHRNA7.
abstract: The α7 nicotinic acetylcholine receptor is known to regulate a wide variety of developmental and secretory functions in neural and non-neural tissues. The mechanisms that regulate its transcription in these varied tissues are not well understood. Epigenetic processes may play a role in the tissue-specific regulation of mRNA expression from the α7 nicotinic receptor subunit gene, CHRNA7. Promoter methylation was correlated with CHRNA7 mRNA expression in various tissue types and the role of DNA methylation in regulating transcription from the gene was tested by using DNA methyltransferase (DNMT1) inhibitors and methyl donors. CHRNA7 mRNA expression was silenced in SH-EP1 cells and bisulfite sequencing PCR revealed the CHRNA7 proximal promoter was hypermethylated. The proximal promoter was hypomethylated in the cell lines HeLa, SH-SY5Y, and SK-N-BE which express varying levels of CHRNA7 mRNA. Expression of CHRNA7 mRNA was present in SH-EP1 cells after treatment with the methylation inhibitor, 5-aza-2-deoxycytidine (5-Aza-CdR), and increased in SH-EP1 and HeLa cells using another methylation inhibitor, zebularine (ZEB). Transcription from the CHRNA7 promoter in HeLa cells was increased when the methyl donor methionine (MET) was absent from the media. Using methylation-sensitive restriction enzyme analysis (MSRE), there was a strong inverse correlation between CHRNA7 mRNA levels and promoter DNA methylation across several human tissue types. The results support a role for DNA methylation of the proximal promoter in regulation of CHRNA7 transcription.
authors: Department of Psychiatry, University of Colorado Denver, Aurora, CO 80045, USA.
authors: Andrew
authors: A
authors: Canastar
authors: Judith
authors: J
authors: Logel
authors: Sharon
authors: S
authors: Graw
authors: Jessica
authors: J
authors: Finlay-Schultz
authors: Christina
authors: C
authors: Osborne
authors: Milda
authors: M
authors: Palionyte
authors: Carla
authors: C
authors: Drebing
authors: Molly
authors: M
authors: Plehaty
authors: Lisa
authors: L
authors: Wilson
authors: Rosemary
authors: R
authors: Eyeson
authors: Sherry
authors: S
authors: Leonard
mesh_terms: D045744:Cell Line, Tumor; D019175:DNA Methylation / Q000187:drug effects / Q000235:genetics*; D044127:Epigenesis, Genetic / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D009928:Organ Specificity / Q000235:genetics; D061251:Primary Cell Culture; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011978:Receptors, Nicotinic / Q000235:genetics* / Q000502:physiology; D014158:Transcription, Genetic / Q000235:genetics / Q000502:physiology*; D064569:alpha7 Nicotinic Acetylcholine Receptor
chemical_list: C579167:Chrna7 protein, human; D011978:Receptors, Nicotinic; D064569:alpha7 Nicotinic Acetylcholine Receptor