title: GSM4151155: U937_H3K4ME3_R2; Homo sapiens; ChIP-Seq
library_construction_protocol: Nuclei extraction was performed using a protocol modified from Schjerven, et al (Schjerven, et al.  Nat Immunol.  2013). 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 10 ug of sheared chromatin was used for ChIP immunoprecipitation with 4 ug of H3K27me3 (Abcam, ab6002, lot GR218433-2 ) or 4 ug of H3K4me3 (Abcam, ab8580, lot GR273043-4 ) used at a ratio of 2.5:1 chromatin to antibody and incubated at 4°C overnight.  Immunoprecipitated complexes were isolated using magnetic protein A/G beads (Pierce, Ref# 88803, Lot TH272704A).  DNA fragments were isolated by uncross-linking the protein-DNA complex overnight at 67°C. The DNA was purified with a PCR Purification kit (Qiagen) and quantified using a Qubit fluorimeter (Life Technologies) prior to the library preparation. Libraries were prepared using the NEBNext ChIPSeq Library Prep (New England Biolabs) for Illumina, and manufacturer's instructions were followed. Libraries were sequenced at the Vermont Integrative Genomics Resource core facility, using the Illumina HiSeq2000, and 50bp single end sequencing reads were generated.
attributes.tag: GEO Accession
attributes.value: GSM4151155