Nuclei extraction was performed using a protocol modified from Dignam et al (Dignam, et al. Nucleic Acids Res 1983). Isolated nuclei were sonicated using a Covaris S-220 Ultrasonic Processor to obtain sheared chromatin with an average peak size of 500 bp. A total of 20 g of sheared chromatin was used for ChIP immunoprecipitation with either 6.5 ug of anti-H3K4me3 anti-H3K27ac, or anti-H3K4ac (Abcam, ab1012 lot#GR80367-1) or 8 ug of anti-H3K27me3 (Millipore -07-449 lot#1764447 or 2475696 ) used at a ratio of 3:1 or 2.5:1 chromatin to antibody, respectively. Immunoprecipitated complexes were purified using Protein-G Dynabeads (Life Technologies 10004D lot#123085320). DNA fragments were isolated by uncross-linking the protein-DNA complex overnight at 65°C. The eluted ChIP-DNA were treated with RNase A (0.2mg/ml final concentration-Life Technologies Cat # AM2269), proteinase K treatment (Life Technologies cat # AM2548) and then phenol extracted, precipitated with ethanol, then resuspended in 10mM Tris. DNA was quantified using a Qubit fluorimeter (Life Technologies) prior to the library preparation. Sequencing libraries were prepared using the TruSeq ChIP sample preparation kit (Illumina cat#9235121 lot #15027084) following instructions provided by the manufacturer. Libraries were then size selected, purified and quantified prior to sequencing by automated DNA sequencing performed in the University of Vermont Cancer Center Advanced Genome Technologies Core (Messier, et al. Oncotarget 2016) .