design: Freshly dissected thoracic tissue was immediately treated with formaldehyde to cross-link proteins to DNA, thereby preserving the three-dimensional chromatin architecture within the nucleus. The cross-linked chromatin was then permeabilized and digested in situ using the DpnII restriction enzyme. The resulting 5' overhangs were filled in with biotinylated nucleotides, effectively marking the ends of the digested DNA fragments. Proximity ligation was then performed under dilute conditions to preferentially join spatially adjacent DNA fragments. After ligation, the cross-links were reversed, and the DNA was purified. The purified DNA, now containing chimeric molecules from interacting genomic regions, was sheared to an average size of 350 bp. Biotin-tagged fragments representing the original ligation junctions were specifically enriched using streptavidin-coated magnetic beads. The enriched DNA was then used as input for a standard Illumina library preparation protocol, including end-repair, A-tailing, adapter ligation, and PCR amplification, to generate the final Hi-C sequencing library.