Many paths to one goal? The proteins that recognize methylated DNA in eukaryotes

DNA methylation is an epigenetically inherited chemical modification that is associated with transcriptional silencing and is essential for mammalian development. The DNA methylation signal is read out by methyl-CpG binding proteins (MBPs) that specifically bind to methylated DNA. Three structurally divergent families of MBPs have been identified so far: the MBD family, the SRA family and a family of proteins with Zinc fingers. In this review, we describe how the distinct families of methyl-CpG binding proteins have evolved, how they each recognize and maintain the DNA methylation mark, and finally how they turn this mark into biological effect.