Dnmt3B is required for genome wide de novo methylation and is essential for development. Defects in Dnmt3B are a cause of immunodeficiency-centromeric instability-facial abnomalies syndrome (ICF), characterized biochemically by hypomethylation of CpG sites in heterochromatin.The synthetic peptide used to raise the antibody Cat. No. 200103 is selected from a sequence within the N-term region of human Dnmt3b. For blocking experiments, a 10 to 100 fold molar excess to antibody is recommended.