A mammalian protein with specific demethylase activity for mCpG DNA

DNA-methylation patterns are important for regulating genome functions, and are determined by the enzymatic processes of methylation and demethylation . The demethylating enzyme has now been identified: a mammalian complementa ry DNA encodes a methyl-CpG-binding domain, bears a demethylase activity th at transforms methylated cytosine bases to cytosine, and demethylates a pla smid when the cDNA is translated or transiently transfected into human embr yonal kidney cells in vitro. The discovery of this DNA demethylase should p rovide a basis for the molecular and developmental analysis of the role of DNA methylation and demethylation.