Exons with low H2Bub1 levels are characterized by high Ser2P-Pol II occupancy. (A) Mean Ser2P-Pol II ChIP-seq levels in HCT116 cells (y-axis) of internal exons (exon), exonic composition regions (ECR), and pseudo exons (pseudo; red, blue, and gray, respectively) in expressed genes. Seventy-five base pairs from each region end and the adjacent 250 bp were plotted (x-axis). (B) Box plot representing the distribution of intron–exon differential H2Bub1 values (intron–exon H2Bub1 difference), based on 75 bp of the exon and the first 250 bp of the adjacent intron, of exon groups in HCT116 cells without (n = 5309) and with (n = 6649) reduced H2Bub1 levels (blue and red, respectively). Thick black line indicates the median value of each group. Boxes enclose values between the first and third quartile. (C) Mean Ser2P-Pol II ChIP-seq levels in HCT116 cells (y-axis) of the same exon groups as in B 75 bp from each exon end and the adjacent 250 bp were plotted (x-axis). (D) Mean Ser2P-Pol II exonic enrichment (y-axis; denoted by mean exon–intron differential Ser2P-Pol II values) in HCT116 cells plotted against the intron–exon H2Bub1 differential (x-axis).
