Figure 1.

Transcriptionally permissive euchromatin may be remodeled in a reversible fashion through the action of a number of chromatin-modifying elements, which act to methylate lysine residues in position 9 (SUV39H associated with constitutive heterochromatin) and position 27 (Polycomb repressor complex associated with facultative heterochromatin). Regions of repetitive DNA have been shown to promote the formation of heterochromatin. Figure used with permission from Yandim PhD thesis 2012, Imperial College London.