TET1 Protein, Human (sf9, FLAG)

TET1 is a dioxygenase that plays a key role in active DNA demethylation by catalyzing the sequential oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC). Beyond DNA demethylation, it broadly regulates chromatin by recruiting histone-modifying complexes to alter histone marks and chromatin accessibility, leading to gene expression activation or repression. TET1 is involved in diverse biological processes, including stem cell maintenance, T- and B-cell development, inflammation regulation, genomic imprinting, neural activity, and DNA repair. Together with QSER1, it protects transcriptional and developmental programs by inhibiting DNMT3A/3B binding to prevent de novo methylation. During development, TET1 may act as an upstream epigenetic regulator of PAX4, potentially through FOXA2 recruitment to a PAX4 enhancer to maintain its unmethylated status, promoting PAX4 expression for beta-cell fate commitment. Under DNA hypomethylation conditions (e.g., in female meiotic germ cells), TET1 may reprogram pericentromeric heterochromatin (PCH) and, independently of its catalytic activity, facilitate chromocenter clustering via PRC1 recruitment. It may also be required for normal meiotic progression and gene activation in oocytes during embryogenesis. TET1 preferentially binds DNA containing CpG dinucleotides over CpH (H=A, T, C), hemimethylated-CpG, or hemimethylated-hydroxymethyl-CpG.