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).

http://www.millipore.com/catalogue/item/17-10035&cid=BIOS-A-EPIG-10013-1102-RC

MBD2 protein methyl-CpG binding domain, Enrichment by methyl-CpG binding domain

Natalja Kurbatova