Promoter Methylation and Tissue-Specific Transcription of the α7 Nicotinic Receptor Gene, CHRNA7
Promoter Methylation and Tissue-Specific Transcription of the α7 Nicotinic Receptor Gene, CHRNA7
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DOI：
10.1007/s12031-011-9663-7
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发表时间：
2012-06-01
影响因子：
3.1
通讯作者：
Leonard, Sherry
中科院分区：
文献类型：
--
作者：
Canastar, Andrew;Logel, Judith;Leonard, Sherry
已知α 7烟碱乙酰胆碱受体调节神经和非神经组织中的多种发育和分泌功能。调节其在这些不同组织中转录的机制还不清楚。表观遗传过程可能在α 7烟碱受体亚基基因CHRNA 7的mRNA表达的组织特异性调节中发挥作用。启动子甲基化与CHRNA 7 mRNA在各种组织类型中的表达相关，并通过使用DNA甲基转移酶（DNMT 1）抑制剂和甲基供体测试DNA甲基化在调节基因转录中的作用。SH-EP 1细胞CHRNA 7 mRNA表达沉默，亚硫酸氢盐测序PCR显示CHRNA 7近端启动子高甲基化。近端启动子在表达不同水平CHRNA 7 mRNA的细胞系HeLa、SH-SY 5 Y和SK-N-BE中低甲基化。甲基化抑制剂5-氮杂-2-脱氧胞苷（5-Aza-CdR）处理后，SH-EP 1细胞中CHRNA 7 mRNA的表达存在，而另一种甲基化抑制剂zebularine（ZEB）处理后，SH-EP 1和HeLa细胞中CHRNA 7 mRNA的表达增加。当培养基中不存在甲基供体甲硫氨酸（MET）时，HeLa细胞中CHRNA 7启动子的转录增加。使用甲基化敏感性限制酶分析（MSRE），在几种人类组织类型中，CHRNA 7 mRNA水平与启动子DNA甲基化之间存在强烈的负相关性。这些结果支持了近端启动子的DNA甲基化在CHRNA 7转录调控中的作用。
The alpha 7 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 alpha 7 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.