Approximately 50,000 flow sorted nuclei were utilized for OMNI ATAC-seq following the protocol by Corces et al. (Corces MR, Trevino AE, Hamilton EG, Greenside PG, Sinnott-Armstrong NA, Vesuna S, et al. An improved ATAC-seq protocol reduces background and enables interrogation of frozen tissues. Nature methods 2017;14:959-62). Nuclei were subjected to transposition reaction following cell lysis and washing steps. The transposition reaction was performed at 37 °C for 30 min in a thermomixer with shaking at 1,000 r.p.m. DNA was purified and indexed ATAC-seq libraries amplified by PCR. The enrichment of accessible regions in each library was determined by real-time PCR targeting known highly accessible and closed chromatin sites and expressed as fold difference. Libraries passing this quality control step were sequenced to 51 base pairs from both ends on an Illumina HiSeq 4000 instrument at the Mayo Clinic Center for Individualized Medicine Medical Genomics Facility.