title: GSM2616789: H3K27me3_ChIPSeq scrambled/ctrl; Homo sapiens; ChIP-Seq
library_construction_protocol: Lysates were clarified from sonicated nuclei and histone-DNA complexes were isolated with antibody. Library preparation was performed by BGI (Hong Kong) using a variation of the Illumina’s standard protocol. The workflow involves end repair of ChIP-enriched DNA using T4 DNA polymerase, Klenow DNA polymerase and T4 polynucleotide kinase to generate blunt ended fragments. ‘A’ bases were added to the 3’ ends using Klenow fragments (3’ to5’ exo minus) to generate DNA fragments for ligation of adapters, which have a single ‘T’ base overhang at their 3’ end. Adapters were ligated to the DNA fragments using DNA ligase. Adapter-modified DNA fragments were amplified by PCR (15 cycles) and size selected (200 ± 25bp) by running PCR products on a 2% agarose gel and purifying using a QIAGEN Gel Extraction Kit (QIAGEN, #28704). The libraries were validated and clusters generated on flow cells, and sequenced using a HiSeq 2500 analyzer.