DNMT3B: a ubiquitous DNA methyltransferase required for genome wide de novo methylation and essential for development. DNA methylation is coordinated with methylation of histones. Numerous cancer cell lines and primary acute leukemias express aberrant DNMT3B transcripts, especially DNMT3B7. Transfection of DNMT3B7 into 293 cells alters the pattern of genes expressed in the transfected cells. Can interact with DNMT1, which might be a co-operative event during DNA methylation. Methylates CpG sites at a rate slower than DNMT3A and much slower than DNMT1. Interacts with SUV39H1, SETDB1, SUMO1 and UBE2I9. Interacts with DNMT1 and DNMT3A. Mutations in DNMT3B have been shown to cause immunodeficiency-centromeric instability-facial anomalies syndrome (ICF). Six alternatively spliced isoforms of the human protein have been reported. Isoform 1 is expressed in all tissues except brain, skeletal muscle and PBMC, 3 is ubiquitous, 4 is expressed in all tissues except brain, skeletal muscle, lung and prostate and 5 is detectable only in testis and at very low level in brain and prostate. Isoforms 4 and 5 are probably not enzymatically active due to the deletion of two conserved methyltransferase motifs.
Protein type: EC 2.1.1.37; Amino Acid Metabolism - cysteine and methionine; Cell development/differentiation; Methyltransferase, DNA; Methyltransferase
Chromosomal Location of Human Ortholog: 20q11.2
Cellular Component: nucleoplasm; intracellular membrane-bound organelle; cytoplasm; nuclear heterochromatin; nucleus
Molecular Function: DNA (cytosine-5-)-methyltransferase activity; protein binding; unmethylated CpG binding; DNA (cytosine-5-)-methyltransferase activity, acting on CpG substrates; metal ion binding; transcription corepressor activity; DNA-methyltransferase activity
Biological Process: negative regulation of histone H3-K9 methylation; response to drug; genetic imprinting; S-adenosylhomocysteine metabolic process; negative regulation of transcription from RNA polymerase II promoter; positive regulation of histone H3-K4 methylation; regulation of gene expression, epigenetic; cytosine methylation within a CG sequence; protein complex localization; methylation-dependent chromatin silencing; negative regulation of gene expression, epigenetic; DNA methylation; S-adenosylmethioninamine metabolic process; gene expression; response to ionizing radiation; positive regulation of neuron differentiation; DNA methylation on cytosine
Disease: Immunodeficiency-centromeric Instability-facial Anomalies Syndrome 1
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