About 100 μg of mononucleosomes were used for each ChIP. ChIP experiments were carried out overnight at 4 °C, in LSDB 350 buffer (glycerol 20%, Hepes 50 mM, MgCl2 3 mM, KCl 350 mM, Na Butyrate 10 mM, Complete Protease Inhibitor Cocktail Tablets (Roche)), with 5 μg of antibodies (rabbit H4K8ac, rabbit antiH4K5ac, rabbit anti H4K8bu, rabbit anti H4K5bu) previously coupled to magnetic beads (Dynabeads protein G (Invitrogen)) for 4 h in 1X PBS, BSA 5 μg/μl. The beads were then washed five times in LSDB 350 buffer, and nucleosomes were eluted with the elution buffer (SDS 1%, 1X TE). DNA was purified from the nucleosomes, and the immunoprecipitated DNA was sequenced. The DNA corresponding to an aliquot of nucleosomes before immunoprecipitation (input) was also sequenced. ChIP-seq libraries were prepared following the Ovation Ultralow DR Multiplex System protocols (NuGEN Technologies INC, San Carlos, CA), followed by a size selection (200-700bp) step using SPRIselect beads (Beckman Coulter, Brea, CA).