title: GSM4808334: Tr1_Maf_cKO_2; Mus musculus; ATAC-seq
library_construction_protocol: 6,000 viable Tr1 cells were sorted for each sample and frozen in BambankerTM cell freezing media (LYMPHOTEC Inc.) at -80℃. For ATAC-seq library preparation, cells were thawed at 37℃, washed once with PBS, and lysed and tagmented in 1X TD Buffer, 0.2ml TDE1 (Illumina), 0.01% digitonin, and 0.3X PBS in 40ml reaction volume following the protocol described by Corces at al. (Corces et al., 2016). The DNA was purified immediately with the MinElute PCR purification kit (QIAGEN),  and then PCR amplified and quantified as we previously described (Wallrapp et al., 2019). The library was sequenced on an Illumina NextSeq 550 system with paired-end reads of 37 base pairs in length.