GSM5114281: K562_WT_ATAC_R1; Homo sapiens; ATAC-seq
ATAC-seq experiments were performed using an adjusted version of the Omni-ATAC protocol (Corces et al., 2017). 100,000 cells were resuspended in 50 ul cold ATAC-resuspension buffer (RSB, 10 mM Tris-HCl pH 7.4, 10 mM NaCl and 3 mM MgCl2 in water) containing 0.1% NP40, 0.1% Tween-20, and 0.01% Digitonin and incubated on ice for 3 minutes. After lysis, 1 ml ATAC-RSB containing 0.1% Tween-20 was added to the mixture and centrifuged for 10 minutes at 1,500 RCF in a pre-chilled (4 °C) fixed-angle centrifuge. Supernatant was removed and nuclei were resuspended in 50 ul transposition mix (2.5 ul transposase Tn5 (100 nM final), 25 ul 2x TD buffer, 16.5 ul 1x PBS, 0.5 ul 1% Digitonin, 0.5 ul 10% Tween-20 in water) (Corces et al., 2017). Transposition reactions were incubated at 37 °C for 30 minutes in a thermomixer. Libraries were made according to protocol described by Buenrostro et al. (Buenrostro et al., 2015).  35-bp paired-end reads were sequenced on an Illumina NextSeq 500 system.