Figure 1.

DNA methylation. (A) DNA methylation and demethylation are under the control of multiple enzymes. (B) Expression level of the responsible enzymes for DNA methylation can alter the methylation state of the promoters of specific genes. An increase in DNMTs will facilitate hypermethylation while a decrease of expression of DNMTs is associated to hypomethylation. On the contrary, a reduction of TET proteins, which mediate demethylation, will promote hypermethylation and an increase of TET can lead to hypomethylation.