Cell pellets were snap frozen prior to fixation for 10 minutes with 1% paraformaldehyde (methanol-free) in PBS  at room temperature. Bare nuclei were suspended in shearing buffer + protease inhibitors (10 Tris HCL pH 8.0, 1 mM EDTA pH 8.0, 0.1% SDS) and sheared on a Covaris M220 ultrasonicator (Microtube, 75W, 5% duty cycle, 200 cycles per burst, 7 minutes). For ChIP-seq, sheared chromatin from drosophila melanogaster S2 cells was added to the mammalian chromatin prior to ChIP at 1:60 to allow for sample normalization. 400 ng of chromatin was used per ChIP reaction and for ChIP-seq, multiple ChIPs were performed and pooled as needed to generate enough post-IP chromatin for library construction. 10-20 ng of pre-IP chromatin containing spike in was kept as an input control. ChIP reactions were performed using a modified Upstate Biotechnology protocol. Briefly, sheared chromatin was diluted 1:10 with dilution buffer + protease inhibitors (21 Tris HCL pH 8.0, 1 mM EDTA pH 8.0, 167 mM NaCl, 1.1% Triton X-100, 0.1% SDS), precleared with 30 ul Fast Flow Protein A sepharose beads (GE Healthcare) and 50 μg bovine serum albumin (BSA) by rotating in a siliconized eppendorf tube at 4 C for 1-2 hours. The precleared chromatin was transferred to a tube containing the antibody of interest (see below), 30 ul Protein A sepharose beads and 50 ug BSA and rotated overnight at 4 C. The bead bound chromatin was washed once each with low salt buffer (20 mM Tris HCl pH 8.0, 2 mM EDTA pH 8.0, 150 mM NaCl, 1% Triton X-100, 0.1% SDS), high salt buffer (20 mM Tris HCl pH 8.0, 2 mM EDTA pH 8.0, 500 mM NaCl, 1% Triton X-100, 0.1% SDS), LiCl buffer (10 mM Tris HCl pH 8.0, 1 mM EDTA pH 8.0, 250 mM LiCl, 1% Nonidet P-40, 1% Deoxycholate) and twice with TE (10 mM Tris HCl pH 8.0, 1 mM EDTA pH 8.0). The chromatin was eluted off the beads with 0.1 M NaHCO3 /1% SDS by rotating at room temperature for 30 minutes, then the supernatant was transferred to a tube with 200nM NaCl and cross links were reversed by incubating overnight at 65 C (input controls were processed along with the ChIP samples from this point on). 10ug Proteinase K was added and the tube was incubated for 2 hours at 37 C, then the DNA was cleaned up using a QiaQuick PCR Purification Kit (Qiagen) and eluted in 50 μl 10 mM Tris HCl pH 8.5. Antibodies used were: H3K27me3 (Cell Signaling 9733) and H3K4me3 (Cell Signaling 9751). Libraries were prepared from 1-5 ng of DNA using the Kapa Hyper Prep protocol with the following modifications: Illumina Truseq DNA UD Index amounts were scaled to the starting material (1.5 µM index for up to 5 ng input, 0.75 µM for less than 2.5 ng and the number of cycles for amplification for each sample were determined with a real time PCR pretest. Completed libraries were analyzed for insert size distribution and quantified using a 4200 TapeStation D5000 ScreenTape assay (Agilent) followed by low pass sequencing with a MiSeq nano kit (Illumina).  Single end 100 cycle sequencing was performed on a NovaSeq 6000 (Illumina).