library_construction_protocol: To reduce the amount of contaminating mitochondrial DNA, we performed an optimized ATAC-seq protocol. In brief, cells were collected and washed once with PBS. The cells were then lysed in ice-cold lysis buffer (10 mM Tris-HCl, pH 7.4; 10 mM NaCl; 3 mM MgCl2; 0.1% NP-40; 0.1% Tween 20; and 0.01% digitonin) for 3 min on ice. Immediately after lysis, nuclei were washed with 1 mL of wash buffer (10 mM Tris-HCl, pH 7.4; 10 mM NaCl; 3 mM MgCl2; and 0.1% Tween 20) and then centrifuged at 500 g for 10 min at 4 °C. To prepare sequencing libraries, a TruePrep DNA Library Prep Kit V2 for Illumina (Vazyme, TD501) was utilized for the following steps.