Cells were washed with ice-cold FACS buffer and were kept on ice until cell sorting. Twenty-five thousand live cells from each condition were sorted into FACS buffer and were pelleted by centrifugation at 500 × g for 5 min at 4 °C in a precooled fixed-angle centrifuge. Cell lines then were tagmented according to the previously described Fast-ATAC protocol (92 (link)). Briefly, all supernatant was removed with care taken not to disturb the not-visible cell pellet. Transposase mixture (50 μL: 25 μL of 2× TD, 2.5 μL of TDE1, 0.5 μL of 1% digitonin, 22 μL of nuclease-free water) (catalog no. FC-121-1030, Illumina; catalog no. G9441, Promega) was added to the cells, and the pellet was dissociated by pipetting. Transposition reactions were incubated at 37 °C for 30 min in an Eppendorf ThermoMixer with agitation at 300 rpm. Transposed DNA was purified using a Qiagen MinElute Reaction Cleanup kit (catalog no. 28204), and purified DNA was eluted in 12 μL of elution buffer (10 mM Tris⋅HCl, pH 8). Transposed fragments were amplified and purified as described previously (93 (link)) with modified primers (94 ). Libraries were quantified using qPCR before sequencing. All Fast-ATAC libraries were sequenced using paired-end, dual-index sequencing on a NextSeq sequencer (Illumina) with 76 × 8 × 8 × 76 cycle reads at an average read depth of 30 million reads per sample.