New publication in "Communications Biology"

TET dioxygenases convert 5-methylcytosine (5mC) preferentially in a CpG context into 5-hydroxymethylcytosine (5hmC) and higher oxidized forms. This process initiates DNA demethylation, but details regarding the effects of the DNA sequences on TET activity are unknown. We investigated oxidation of DNA substrates with randomized sequence context  and show pronounced up to 80-fold flanking sequence effects on the catalytic activities of TET enzymes. TET flanking sequence preferences are reflected in genome-wide and local patterns of 5hmC and DNA demethylation in human and mouse cells indicating that they influence genomic DNA modification patterns in combination with locus specific targeting of TET enzymes.