library_construction_protocol: Enriched mouse colon crypt cells were washed once in 1x PBS, resuspended in ice-cold ATACseq lysis buffer (100 μl; 10 mM Tris-HCl pH 7.4, 10 mM NaCl, 3 mM MgCl2, 0.1% IGEPAL CA-630 and protease inhibitor) and centrifuged for 500 rpm, 10 minutes at 4 °C.  After centrifugation, pellets were washed briefly in 1x PBS before incubating in the transposase reaction mix (12.5 μl 2 × TD buffer, 2 μl transposase; Illumina) and nuclease-free water (10.5 μl) for 30 minutes at 37° C. Genomic DNAs were eluted using MinElute kit; QIAGEN. After DNA purification (MinElute kit; QIAGEN), eluted DNA (1 μl) was used in a quantitative PCR (qPCR) reaction to estimate the optimum number of amplification cycles. Purified fragmented DNA was amplified by PCR.