The duodenum was flushed with cold PBS, opened longitudinally, and cut into pieces. Epithelium was released by incubation in 3 mM EDTA/PBS at 4°C with rotation and shaking; the supernatant was collected after discarding the tissue. For MNase-ChIP, isolated epithelial cells were resuspended in digestion buffer (50 mM Tris-HCl pH 7.6, 1 mM CaCl₂, 0.2% Triton X-100, 5 mM Na butyrate, plus protease inhibitors) and digested with 0.67 U/ml MNase (Sigma #N3755) for 5 min at 37°C. The reaction was stopped with 5 mM EDTA/10 mM Tris (pH 7.6), and samples were dialyzed into chromatin RIPA buffer (10 mM Tris pH 7.6, 1 mM EDTA, 0.1% SDS, 0.1% Na-deoxycholate, 1% Triton X-100). Immunoprecipitation was performed overnight at 4°C using an H3K27Ac antibody (Abcam ab4729). Further processing of the IP material followed the standard sonication-ChIP protocol (final SDS concentration of 0.13%). Libraries were prepared with the Rubicon Genomics ThruPLEX DNA-seq Kit.