Quantitative Western Blot Analysis

Western Blots were performed as described previously [90 (link)]. In total, 20 µg of whole cell protein lysates or 3 µg of histone extract were used for western blotting. β-Actin was used as housekeeper and loading control for whole cell lysates. Western blots of histone extracts were stained with Coomassie Brilliant Blue R 250 (Roth, Karlsruhe, Germany) and total H3 or H4 antibody to verify equal loading. For antibody details, see supplement (Additional file 12: Table S2 D). The ChemiDoc Imaging System (Bio-Rad Laboratories, Feldkirchen, Germany) was used for detection. Pixel density was analyzed using the ‘Image Lab’ software provided by Bio-Rad.