DNMT 3B | DNA Methyl transferase 3B

DNMT3B well known as DNA (cytosine-5)-methyltransferase 3B is a nuclear protein belonging to the C5-methyltransferase family with an ADD-type zinc finger and a PWWP domain. This DNA associated enzyme is essential for genome wide de novo methylation and is required for development (at least in mouse) and catalytically methylating cytosines in CpG pairs. DNA methylation is coordinated with methylation of histones. Out of the six isoforms reported isoforms 4 and 5 are probably not functional due to the deletion of two conserved methyltransferase motifs. DNMT3B forms a universal repressor complex containing DNMT3B and ZHX1. It interacts with other proteins like HDAC1, HDAC2, HP1 proteins, SUV39H1, and components of the histone methylation system, the ATP-dependent chromatin remodeling enzyme SMARCA5. Ubiquitously expressed in most of the tissues. Defects in DNMT3B are a cause of a rare autosomal recessive disorder immunodeficiency-centromeric instability-facial anomalies syndrome (ICF) biochemically characterized by hypomethylation of CpG sites in some regions of heterochromatin.