TET-mediated DNA hydroxymethylation is negatively influenced by the PARP-dependent PARylation.

Background: Poly(ADP-ribosyl)ation (PARylation), a posttranslational modification introduced by PARP-1 and PARP-2, has first been implicated in DNA demethylation due to its role in base excision repair. Recent evidence indicates a direct influence of PARP-dependent PARylation on TET enzymes which catalyse hydroxymethylation of DNA-the first step in DNA demethylation. However, the exact nature of influence that PARylation exerts on TET activity is still ambiguous.