ADDz domain found in DNA (cytosine-5) methyltransferases (C5-MTases) 3a (Dnmt3a)
Dnmt3a is a member of the Dnmt3 family and is a protein with de novo DNA methyltransferase activity. Dnmt3 family members are Dnmt3a, Dnmt3b, and Dnmt3l the non-enzymatic regulatory factor. Dnmt3a is recruited by Dnmt3l to unmethylated histone H3 and methylates the target. Dnmt3a has a variable region at the N-terminus, followed by a conserved PWWP region and the cysteine-rich ADDz domain. ADDz_Dnmt3a is an active catalytic domain of Dnmt3a. DNA methylation is an important epigenetic mechanism involved in diverse biological processes such as embryonic development, gene expression, and genomic imprinting. The methyltransferase activity of Dnmt3a is not only responsible for the establishment of DNA methylation pattern, but is also essential for the inheritance of these patterns during mitosis. The ADDz_Dnmt3 domain is a PHD-like zinc finger motif that contains two parts, a C2-C2 and a PHD-like zinc finger. PHD zinc finger domains have been identified in more than 40 proteins that are mainly involved in chromatin mediated transcriptional control; the classical PHD zinc finger has a C4-H-C3 motif that spans about 50-80 amino acids. In ADDz, the conserved histidine residue of the PHD finger is replaced by a cysteine, and an additional zinc finger C2-C2 like motif is located about twenty residues upstream of the C4-C-C3 motif. A knockout of Dnmt3a has been shown to be lethal in the mouse model.
Jiyao W et al.(2023). "The conserved domain database in 2023.",