Figure 3. PRC1-mediated gene repression does not rely directly on PRC2 or H3K27me3.

(A) Genomic snapshots of typical Polycomb target genes, showing cChIP-seq signal for RING1B, H2AK119ub1, SUZ12 and H3K27me3 in PRC1^deg cells treated with IAA for the indicated times.

(B) Metaplot analysis of SUZ12 cChIP-seq at promoters of the three groups of genes defined by the earliest time of derepression in PRC1^deg cells treated with IAA for the indicated times.

(C) As in (B) for H3K27me3 cChIP-seq.

(D) Dynamics of gene expression changes in comparison with the reduction in cChIP-seq signal (TSS ± 2.5 kb) for Polycomb factors and associated histone modifications. Shown are median changes relative to untreated cells for genes derepressed after 2h of IAA treatment (n = 1044).

(E) Schematic illustration of the PRC2^deg system. Endogenous SUZ12 is N-terminally tagged and degraded by the proteasome after addition of the dTAG-13 compound.

(F) Western blot analysis of SUZ12, H3K27me3 and H2AK119ub1 in wild type (WT) and PRC2^deg cells (untreated and treated with dTAG-13 compound). Shown are representative results from n=4 independent experiments.

(G) MA plots depicting gene expression changes (cnRNA-seq) in PRC2^deg cells treated with dTAG-13 compound for 2h (left) or PRC1^deg cells treated with auxin for 2h (right). Arrows denote numbers of differentially expressed genes labelled in red (padj < 0.05, fold change > 1.5).