ChIP was performed using BNC2 (Sigma, HPA018525) or H3K27ac antibody (Active Motif ref 39685). TruSeq ChIP Sample Preparation Kit (BNC2) or DNBseq involving Probe-Anchor Synthesis (cPAS), linear isothermal Rolling-Circle Replication  and DNA Nanoballs (DNBTM) technology, followed by high-resolution digital imaging.