title: GSM3754721: CART19 cells, ATAC  Nalm6 WT Stim rep 1; Homo sapiens; ATAC-seq
library_construction_protocol: cells were processed following the Omni ATAC-seq protocol. To isolate nuclei, cells were washed 2x with ice-cold PBS followed by resuspension in ATAC- resuspension buffer containing 0.1% NP40, 0.1% Tween-20 and 0.01% Digitonin. Cells were incubated on ice for 3 minutes and washed out with ATAC- resuspension buffer containing (0.1% Tween20). Nuclei were pelleted and transposed with Tn5 transposase. nuclei were isolated from 50,000 sorted CART19 cells, followed by the transposition reaction using Tn5 transposase (Illumina) for 30 minutes at 37°C with 1000rp mixing.  Purification of transposed DNA was completed with DNA Clean and Concentrator (Zymo) and fragments were barcoded with ATAC-seq indices.  Final libraries were double size selected using AMPure beads prior to sequencing.