title: GSM9284648: LY2 cells, siCDK12 (ER IP), rep 4; Homo sapiens; ChIP-Seq
library_construction_protocol: DNA/protein complexes were cross-linked with 1 % formaldehyde for 10 minutes and quenched with 1 mol/L glycine. Cells were washed with PBS, harvested in PBS supplemented with protease inhibitors and centrifuged at 3000 g for 10 minutes at 4°C. Cell pellets were lysed, and chromatin was extracted as described in Schmidt et al. 2009. Chromatin samples were sonicated using Bioruptor Pico (Diagenode), resulting in an average chromatin fragment size of 200 bp. Triton X-100 was added to sonicated lysates (1 % final concentration) and subjected to centrifugation at 20,000 g for 10 minutes at 4°C. Library preparation and DNA sequencing (10 ng minimum DNA) were performed by BGI (Hong Kong) as per standard company protocol.