ChIP on EP300 was performed as described previously (Jacobs et al. 2014 (link)), with an excess of EP300 antibody (C-20; sc-585 X; Lot B0211 and Lot E2610). For H3K27ac and H3K4me3 data, ChIP was based on Vermunt et al. (2014) (link), with 5 µg H3K27ac (Abcam ab4729, Lot GR3303561-2) and 6 µg H3K4me3 (Millipore 07-473, Lot 3394198) per sample. ChIP-seq data analysis on EP300 was performed as described previously (Jacobs et al. 2014 (link)). For the full procedure, see Supplemental Material.