Mechanisms of TET protein-mediated DNA demethylation and its role in the regulation of mouse development.

TET (ten-eleven translocation) protein family includes three members TET1, TET2 and TET3, which belong to alpha-ketoglutaric acid ( α-KG )- and Fe(2+)-dependent dioxygenase superfamily, and have the capacity to convert 5-methylcytosine (5 mC) to 5-hydroxymethylcytosine (5 hmC), 5-formylcytosine (5 fC) and 5-carboxylcytosine (5 caC). At present, growing lines of evidence indicate that TET proteins are involved in the control of active or passive DNA demethylation via different mechanisms; moreover, their activities may be regulated by some cellular factors. TET proteins play vital roles in modulating mammal development, including primordial germ cell formation, embryonic development, stem cells pluripotency, nerve and brain development, etc. The identification of biological roles of TET proteins will open a new field in epigenetic research, and these studies on TET proteins are of great significance to life science research. Here, we review TET proteins from their structure, molecular mechanisms of DNA demethylation and function in the regulation of mouse development, which may provide the basis for understanding the functions of TET proteins.