Figure 1
From: Genome-wide assays that identify and quantify modified cytosines in human disease studies
Cytosine variants and their production. We show how cytosine within DNA can be acted upon by DNA methyltransferases (DNMT) to generate 5-methylcytosine (5mC), which can subsequently be oxidized by TET enzymes through the 5-hydroxymethylation (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC) variants, favoring the activity of thymine DNA glycosylase to create an abasic site that can then be repaired to add back an unmethylated cytosine to complement the guanine on the other strand. As well as alpha-ketoglutarate (α-KG), another known TET enzyme cofactor is ascorbic acid (vitamin C).