title: GSM4011091: 1--2: CTRL 02; Homo sapiens; ATAC-seq
library_construction_protocol: Following an Omni-ATAC protocol, cells were trypsinized and resuspended in 1 ml cold ATAC-Seq resuspension buffer, and centrigued at 500 rcf for 5 min in a pre-chilled fixed-angle centrifuge. After centrifugation, 900 ul of supernatant was aspirated, the remaining 100 ul of supernant was carefully taken to avoid the cell pellet. Pellets were then suspended in 50 ul ATAC-Seq RSB containing 0.1% NP40, 0.1% Tween-20 and 0.01% digitonin, with cell lysis incubated on ice for 3 min. After lysis, 1 ml of ATAC-Seq RSB containing 0.1% Tween-20 was added. Nuclei were then centrifuged for 10 min at 500 rcf at 4 C, with supernant removed and nuclei resuspended in 50 ul transposition mix. Libraries were prepared according to Illumina's instructions accompanying the Nextera DNA Flex Library Prep Kit (FC-121-1030; Part# 1000000025416 v04). Briefly, nuclear pellets were subject to tagmentation by Bead-linked Transposomes (RLT), which were designed to tagment DNA with adapter sequences. Upon completion, tagmented products were cleaned up, and a pre-optimized PCR procedure was followed to amplify tagmented DNA. The resultant library of barcoded and amplified DNA was purified with a double-sided bead purification procedure. The library pool was quantified using a Bioanalyzer 2200 (Agilent) to assess size range of amplified DNA fragments and with a dsDNA fluorescent dye method, Quant-iT PicoGreen dsDNA Assay kit to quantify DNA fragments generated. ATAC libraries were pooled at equimolar concentrations and were sequenced multiplexed on the Illumina NovaSeq 6000 with 50-bp paired-ends.