Control (n=3) and D164A (n=3) mice were sacrificed 2d pi and processed independently for ATACSeq library preparation, following the protocol by Buenrostro et al, 2015. Briefly, single cell suspension of duodenal crypts was performed as described (Sato and Clevers, 2013). 50'000 cells were lysed in 50ml cold Lysis buffer (10 mM Tris-HCl,pH 7.4, 10 mM NaCl, 3 mM MgCl2, 0.1% IGEPAL CA-630). After centrifugation at 500 g for 10 min at 4°C, cells were resuspended in 50 mL 1X Illumina transposition mix (25ml Tagment DNA Buffer, 2.5ml Tagment DNA Enzyme, 22.5ml nuclease-free H2O) and incubated for 30 min at 37°C on a shaker. Immediately following the transposition reaction, DNA was purified using the QIAgen MinElute PCR Purification Kit according to the manufacturer's instructions. Library was amplified with Nextera Sequencing primers in NEBNext Hot Start High-Fidelity 2X PCR master mix for 5 cycles. The appropriate number of additional PCR cycles was determined by qPCR. Amplified libraries were purified using the QIAgen MinElute PCR Purification Kit. DNA was eluted in 20ml EB buffer and quantified and visualized for quality control with a 2200 TapeStation System (Agilent). Libraries were sequenced on an Illumina HiSeq2500 with paired end 70 bp read configuration.