library_construction_protocol: 14 days after gRNA virus transduction, cells were harvested with Accutase, pelleted, and the ATAC-seq protocol from Corces et al. 2017 was followed with 45,000 cells per sample with the following alterations: KAPA polymerase (Roche, KK2101) was used in the PCR step, following reaction condition recommendations for KAPA polymerase. Libraries were sequenced with 2x25 paired-end reads with a coverage of 50 million reads per sample. ATAC libraries were prepared according to Corces et al. 2017 Omni-ATAC protocol, with KAPA polymerase as the polymerase used for library PCR.