library_construction_protocol: Cells were crosslinked with 1% formaldehyde for 12 minutes. Chromatin was digested in situ using 2,750 U of DpnII overnight on ~5 million cells permeabilised with 0.3% SDS. After a fill-in reaction containing biotinylated dATP, ends were ligated with 2,000 of T4 DNA ligase. Purified DNA was sonicated to 300-700 bp, and sequencing adaptors ligated using NEBnext Ultra II reagents. To match the HiChIP protocol, DNA was heat denatured, followed by purification, isolation of ligated fragments using streptavidin beads, and library amplification. Libraries were prepared using the NEBNext ultra II DNA library prep kit.