library_construction_protocol: ATAC-seq was performed according to the previously described protocol (Buenrostro et al., 2015) with modifications. Briefly, 50,000 cells were washed with cold PBS and resuspended in lysis buffer to extract nuclei. The nuclei were cold-centrifuged at 500 x g for 10 min. The nuclei pellet was incubated with transposition reaction buffer for 30 min. at 37 °C. The DNA was purified using the PCR Purification Kit (Qiagen).The eluted transposed DNA was submitted to the PCR using Q5 High-Fidelity Polymerase (NEB). DNA was amplified with 11-12 cycles of PCR.