library_construction_protocol: Frozen tissue was ground in a mortar and pestle, homogenized into a slurry in 250 µl of Buffer S and moved directly to sonication. Post sonication, lysate was diluted 10x with Buffer F for use in pulldowns. 50 µl of diluted lysate was saved as input. αH2A.Z (2 μg/mL), αMBD9 (2 μg/mL) or αPIE1 (3 μg/mL) antibodies were added to diluted lysates and incubated overnight at 4°C on a nutator for end-over-end mixing. 20 µl of Protein G Dynabeads (Invitrogen) per replicate were washed in excess Buffer F, resuspended to their original volume and added to each pulldown. Samples were incubated with beads at 4°C on a nutator for 2 hours. ChIP DNA was extracted via the MinElute PCR Purification Kit (Qiagen) Sequencing libraries were made using the ThruPLEX DNA-Seq Kit (Takara).