library_construction_protocol: For ACT-seq library preparation, permeabilised lung endothelial nuclei were incubated with histone-mark antibodies, followed by addition of pre-assembled Protein A/G–Tn5 adaptor complexes; after tagmentation, DNA was purified (phenol–chloroform/ethanol or column) and quantified with Qubit dsDNA HS.. Tagmented DNA was PCR-amplified with indexed primers to add full Illumina adapters (Phusion High-Fidelity or equivalent), size-selected (~200–700 bp), QC'd, and sequenced as paired-end reads on an Illumina NextSeq 2000.