title: GSM3184881: Pooled input ChIPSeq; Homo sapiens; ChIP-Seq
library_construction_protocol: Cells were formaldehyde fixed for 15 minutes (1% formaldehyde, 100 mM NaCl, 0.1 mM EDTA pH8.0, 5 mM Hepes pH 7.9).  Fixation was stopped with 2.5M glycine and cells were washed 2X in PBS/0.5% Igepal CA-630.  Cell pellets were snap frozen and chromatin was isolated by the addition of lysis buffer, followed by disruption with a Dounce homogenizer. Lysates were sonicated and the DNA sheared to an average length of 300-500 bp. Genomic DNA (Input) was prepared by treating aliquots of chromatin with RNase, proteinase K and heat for de-crosslinking, followed by ethanol precipitation. Illumina sequencing libraries were prepared from the ChIP and Input DNAs by the standard consecutive enzymatic steps of end-polishing, dA-addition, and adaptor ligation. After a final PCR amplification step, the resulting DNA libraries were quantified and sequenced on Illumina's NextSeq 500 (75 nt reads, single end).