Nucleic Acids Research Advance Access originally published online on November 22, 2007
Nucleic Acids Research 2008 36(1):330-341; doi:10.1093/nar/gkm1028
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Nucleic Acids Research, 2008, Vol. 36, No. 1 330-341
© 2007 The Author(s)
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Molecular Biology |
CpG methylation plays a vital role in determining tissue- and cell-specific expression of the human cell-death-inducing DFF45-like effector A gene through the regulation of Sp1/Sp3 binding
State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
*To whom correspondence should be addressed. Tel: +86-21-54921115; Fax: +86-21-54921011; Email: mjzhao{at}sibs.ac.cn
Received August 2, 2007. Revised October 26, 2007. Accepted October 29, 2007.
GenBank Accession Number EF672106
Cell-death-inducing DFF45-like effector A (CIDE-A) belongs to a family of proapoptotic proteins, the expression of which is highly restricted in human tissues and cells. Here, the core region of the human CIDE-A promoter was characterized. Surprisingly, two Sp1/Sp3-binding sites, rather than tissue-specific transcription factors, were found to be required for the promoter activity. Although the ubiquitously expressed Sp1 and Sp3 were crucial, they alone could not adequately regulate the specific expression of CIDE-A. We found that the expression of CIDE-A was further regulated by CpG methylation of the promoter region. By performing bisulfite sequencing, we observed dense CpG methylation of the promoter region in tissues and cells with low or no expression of CIDE-A but not in tissues with high level of CIDE-A expression. In vitro methylation of this region showed significantly reduced transcriptional activity. Treatment of CIDE-A-negative cells with 5-aza-2'-deoxycytidine demethylated the CpG sites; this opened the closed chromatin conformation and markedly enhanced the binding affinity of Sp1/Sp3 to the promoter in vivo, thereby restoring CIDE-A expression. These data indicated that CpG methylation plays a crucial role in establishing and maintaining tissue- and cell-specific transcription of the CIDE-A gene through the regulation of Sp1/Sp3 binding.