Fig. 5
From: Hypoxia increases genome-wide bivalent epigenetic marking by specific gain of H3K27me3
Hypoxia increases genic bivalent marking. a Bar diagrams depicting increased bivalency (gene numbers) by gain of H3K4me3 (green), gain of H3K27me3 (red) or gain of both H3K4me3/H3k27me3 marks (orange) during hypoxia and reoxygenation. Gray color bars indicate the number of bivalent marked genes already present at the indicated time points. b Bar graphs showing relative changes of H3K4me3-mono, H3K27me3-mono and bivalent marking at the indicated time point. c Bar graph depicting percentage match of bivalently marked genes in MCF7 cells (at different experimental time points) and in ESC. Comparison of bivalently marked MCF7 loci with published data sets revealed 11–13% (reference data set: [28]; data not shown) to 25% target overlap (reference data set: [49]). d Bar graph depicting changes in expression levels of bivalently marked (4 genes: ARRB1, ADCY5, AKAP1, FAM217B; representing a total of n = 225) and H3K4me3-only marked (4 genes: ASB8, RPL31P17, LRRC28, PPAT; representing a total of n = 5755) genes under the indicated experimental conditions. Gene categories were defined based on low expression levels at t = 0 (log2-based expression value 3.68–6.64). Normoxic expression values (t = 0; left-most, gray bars) were set to 1; orange bars represent transcriptional activity at the indicated H3K4me3/gain H3k27me3 markers at 24-h chronic hypoxia (24), 6 (6c) or 18 (18c) cycles of oxygen deprivation/reoxygenation; green bars represent transcriptional activity at the indicated H3K4me3-only marked loci (24 h, 6c, 18c). Marker expression was normalized to the geo-mean of beta-actin and cyclophilin A. Asterisks indicate statistical significant differences as depicted in the figure; ns nonsignificant difference