Insights & Perspectives
Mammalian methyl-binding proteins: What might they do?
Article first published online: 30 SEP 2010
Copyright © 2010 WILEY Periodicals, Inc.
Volume 32, Issue 12, pages 1025–1032, December 2010
How to Cite
Joulie, M., Miotto, B. and Defossez, P.-A. (2010), Mammalian methyl-binding proteins: What might they do?. Bioessays, 32: 1025–1032. doi: 10.1002/bies.201000057
- Issue published online: 18 NOV 2010
- Article first published online: 30 SEP 2010
- Manuscript Accepted: 24 AUG 2010
- Manuscript Revised: 19 AUG 2010
- Manuscript Received: 7 MAY 2010
- DNA methylation;
- gene expression;
- transcription factors
CpG islands (CGIs) are regions enriched in the dinucleotide CpG; they constitute the promoter of about 60% of mammalian genes. In cancer cells, some promoter-associated CGIs become heavily methylated on cytosines, and the corresponding genes undergo stable transcriptional silencing. Hypermethylated CGIs attract methyl-CpG-binding proteins (MBPs), which have been shown to recruit chromatin modifiers and cause transcriptional repression. These observations have led to the prevalent model that methyl-CpG-binding proteins are promoter-proximal transcriptional repressors. Recent discoveries challenge this idea and raise a number of questions. Here we discuss the following issues: what are other possible roles for the known MBPs? Why are these proteins not essential in mammals? Are there other MBPs left to discover? Could CpG methylation be nonessential?