Correlation of histone modifications and gene expression. a Correlation of summarized net enrichment of five histone modifications (H3K4me3, H3ac, H3K79me2, H3K27me3, and H3K9me3) and PolII (y-axis) at genes with expression levels of the corresponding ~23,000 genes (x-axis). Arbitrary values of net enrichment were calculated by summing the individual features (enriched basepair (bp) area multiplied by highest peak score) of all histone modifications, while considering the effect of silencing histone modifications (H3K27me3 and H3K9me3) as a negative activation, and subsequently normalizing for the number of activating and silencing histone modifications present at each promoter. Genes were clustered into bins of 100 genes each. b Increase of Log2 enrichment scores (y-axis) upon up- or downregulation of gene expression levels between murine hematopoietic stem cells (HSC) and splenic CD4+ T cells (T cell) for five histone modifications (H3K4me3, H3ac, H3K79me2, H3K27me3, and H3K9me3) and PolII (x-axis). A total of 12 different fold change categories for up- and downregulation of gene expression is shown (fold changes of 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, and 7). The increase in Log2 peak scores for the histone modifications and PolII was averaged at gene promoters belonging to each category of fold change in gene expression (y-axis).