Figure 2.

Schematized characterization of repressed and active Polycomb targets. Genomic sites occupied by PRC proteins in undifferentiated, primitive cells (left), and in cells in more advanced stages of differentiation pathways (right). Color-coded repressed and active targets show a higher proportion of active targets in differentiated cells. Polycomb-induced modifications are prevalent on repressed targets. Below are simplified views of ChIP profiles showing distinctive Polycomb occupancies (PRC, encompassing all classes of assemblies) and its increased presence on active enhancers (H3K27ac).