H3K27me3 and promoter-promoter interactions. (A) Cartoon of interactions between promoters, which are enriched for the H3K27me3 mark. We tested promoter-promoter interactions for overrepresentation of H3K27me3 on both promoters, including convergent, divergent, and tandem promoter pairs. (B) Correlation between H3K27me3 and gene expression. In the four control sets, upon shifting the coordinates of H3K27me3 peaks, genes marked with H3K27me3 are no longer associated with reduced expression. (C) Fraction of promoters enriched with H3K27me3 relative to all promoter-promoter interactions. Loops shorter than 6 kb were not considered. (D) Correlation between H3K27me3 and promoter-promoter interactions. Shifted controls as in B. P-values indicate significance relative to the permutation-based null distribution of the background.
