part_of part of part of nucleic acid library construction protocol enrichment of methylated DNA http://www.millipore.com/catalogue/item/17-10035&cid=BIOS-A-EPIG-10013-1102-RC MBD2 protein methyl-CpG binding domain Natalja Kurbatova The isolation and enrichment of methylated DNA by using methyl CpG binding proteins, MBD2b protein in particular. Methylation of cytosines located 5' to guanosine is known to have a profound effect on the expression of many eukaryotic genes. In normal cells methylation occurs predominantly in CG-poor regions, while CG-rich areas, called CpG-islands remain unmethylated. The exceptions are the extensive methylation of CpG islands associated with transcriptional inactivation of regulatory regions of imprinted genes and genes on the inactive X-chromosome of females. Aberrant methylation of normally unmethylated CpG islands has been documented as a relatively frequent event in immortalized and transformed cells and has been associated with transcriptional inactivation of defined tumor suppressor genes in human cancers. To evalute the methylation status of either a specific locus or an entire genome, the isolation and enrichment of methylated DNA can be a useful first step. A high-affinity GST-MBD protein pre-bound to a magnetic bead is used to enable this enrichement (Fraga M.F., et al. (2003). Nuc. Acids Res, 31, 1765–1774). Enrichment by methyl-CpG binding domain enrichment process