Figure 4.

PRC1 Catalytic Activity Drives Canonical PRC1 Occupancy and Long-Range Polycomb Chromatin Domain Interactions

(A) Genomic snapshots of Polycomb target genes, showing cChIP-seq for RING1B, H2AK119ub1, H3K27me3, and PCGF2 (cPRC1) in PRC1^CPM cells.

(B) Metaplot analysis of PCGF2 cChIP-seq at PCGF2 target sites in PRC1^CPM cells.

(C) Heatmap analysis of data shown in (B). Genomic regions were sorted based on RING1B occupancy in untreated PRC1^CKO ESCs.

(D) ChIP-qPCR for PHC1 at a panel of Polycomb target genes in PRC1^CPM cells. B-actin is an active gene not bound by PHC1. Error bars show SEM (n = 3).

(E) Genomic snapshots of two regions encompassing classical Polycomb target sites used as baits in CaptureC (bait probe positions are marked by dashed red lines). H3K27me3 and PCGF2 cChIP-seq data in PRC1^CPM cells are shown at the top. Below is the bait interaction landscape measured by CaptureC in PRC1^CPM cells (untreated and OHT-treated) and auxin-treated Ring1a^−/−;AID-RING1B (RING1B^deg) ESCs (relative to the Control cell line with intact PRC1). Arrows illustrate long-range PRC1-dependent interactions.

(F) Meta-analysis of interactions between bait Polycomb target regions and other PCGF2 target sites (n = 130) in cells described in (E). Read density is shown relative to the untreated PRC1^CPM cells.

(G) Boxplot analysis of CHiCAGO scores for the interactions between the bait Polycomb target regions and other PCGF2 target sites (n = 130) for cells described in (E).

(H) A schematic summarizing the model in which deposition of H2AK119ub1 by PRC1 drives accumulation of PRC2 and deposition of H3K27me3 at target sites, promoting cPRC1 binding and long-range interactions between these regions.

See also Figure S4.