Instrument: Illumina NovaSeq 6000
Strategy: ChIP-Seq
Source: GENOMIC
Selection: ChIP
Layout: PAIRED
Construction protocol: K562 dTAG-BRD4 cells were crosslinked with 1% formaldehyde for 5 min at room temperature, NIH3T3 cells were crosslinked for 8 min. After combining NIH3T3 and K562 dTAG-BRD4 cells in a ratio of 1:5, cells were lysed as described by Baluapuri et al. (2019), followed by sonication using a Covaris E220evolution at intensity 4, duty cycle 5%, 200 cycles per burst for 20 min. Lysates were pre-cleared by centrifugation. Lysates and antibodies coupled to Dynabeads Protein G (Thermo Fisher Scientific) were incubated at 4°C overnight with rotation. Afterwards, the beads were washed with buffers prepared according to Baluapuri et al. (2019). DNA fragments were purified using the ChIP DNA Clean & Concentrator kit (Zymo). Libraries were constructed from 6 to 30 ng DNA using the NEBNext Ultra II DNA kit (NEB) according to the manufacturer's instructions. After purifying the amplified libraries with AMPure XP beads (Beckman Coulter), fragments of 200 to 500 bp were extracted from an 8% TBE gel. Library quality and quantity were assessed using BioAnalyzer HS DNA (Agilent) and Qubit dsDNA HS (Thermo Fisher) assays, respectively.