Fig. 1

VPA treatment induces global histone H3K56 hyperacetylation. A Treatment of mESCs with 2 mM VPA for 48 h increases the levels of H3K56 acetylation (green) compared to untreated control cultures. Scale bar = 20 μm. B High-resolution confocal imaging of individual control and VPA-treated nuclei stained with H3K56ac (green). DNA is counterstained using DAPI (blue). Fluorescence intensity across nuclei is visualized by line scan (red arrows) graphs. DAPI bright chromocenters are highlighted (shaded blue). C High-content confocal analysis using threshold maps for the quantification of H3K56ac fluorescence intensity and nuclear circumference reveals a higher proportion of nuclei with bright H3K56ac staining (yellow) in VPA-treated cultures compared to controls. Nuclear circumference measurements indicate no significant differences (Cntl: n = 98; VPA: n = 108). Scale bar = 20 μm. Data are expressed as the mean ± SD of three independent replicates. Unpaired t-test, two tailed resulted in P < 0.001. n.s.—not significant