GSE43262
Ascorbic acid enhances Tet-mediated 5-methylcytosine oxidation and promotes DNA demethylation in mammals.
DNA demethylation occurs in multiple cellular processes but its regulation is poorly understood. Here we report that a vital nutrient factor ascorbic acid (AA), or vitamin C (Vc), induces DNA demethylation in mammalian cells. The levels of active 5mC oxidation products, 5-formylcytosine and 5-carboxylcytosine, increase by more than one magnitude of order in mouse ES cells when cultured in the presence of AA. In cells deleted of Tet1 and Tet2 dioxygenase genes, AA does not facilitate 5mC oxidation. The AA effect is however restored when Tet2 was re-expressed in the mutant cells. The enhancing effect of AA on 5mC oxidation and DNA demethylation was also observed in a mouse model deficient in AA synthesis. Our results thus reveal a role of AA in the regulation of DNA modification, which might mediate a plethora of functions of AA. Overall design: Examination of 5hmC levels with or without AA in mouse ES cells