Figure 2

Primary structure and function of human TET proteins. All TET proteins present a double-stranded β helix (DSBH), a cysteine-rich domain, and one 2-oxoglutarate and three iron (II) binding sites in the carboxyl terminus, which constitute their dioxygenase catalytic domain. An amino-terminal CXXC zinc finger domain is only identified in TET1 and TET3, allowing these enzymes to bind DNA directly to CpG. Recently, the CXXC4 gene (also named inhibition of the Dvl and Axin complex, IDAX), located upstream of TET2 on chromosome 4, has been reported to tether TET2 to DNA through a physical interaction [65]. AA, amino acid; TET, ten-eleven translocation.