title: Mammalian methyl-binding proteins: what might they do?
abstract: 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?
authors.affiliation: CNRS UMR7216, Université Paris Diderot, Paris, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Joulie
authors.forename: Benoit
authors.initials: B
authors.lastname: Miotto
authors.forename: Pierre-Antoine
authors.initials: PA
authors.lastname: Defossez
mesh_terms: D000818:Animals; D042002:Chromatin Assembly and Disassembly; D018899:CpG Islands; D003596:Cytosine; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D020868:Gene Silencing; D006801:Humans; D051783:Methyl-CpG-Binding Protein 2 / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D037941:Silencer Elements, Transcriptional; D014158:Transcription, Genetic
chemical_list: D004268:DNA-Binding Proteins; D051783:Methyl-CpG-Binding Protein 2; D012097:Repressor Proteins; D003596:Cytosine