cells were washed three times, trypsinized, and strained through a 40 µm cell strainer Approximately 10,000 cells were captured per lane of a 10x Chromium chip (Next GEM Chip G) using Chromium Next GEM Single Cell 3ʹ HT Reagent Kits v3.1 with Feature Barcoding technology for CRISPR Screening (10x Genomics, Inc, Document number CG000418, Rev D). CROP-seq protospacer sequences were amplified from barcoded cDNA.