Fig. 3

gRNA capture approaches. Due to the lack of poly-A sequence, specific measures are required for gRNA detection at single-cell level. a Each gRNA can be indirectly identified by a coupled DNA- or protein-based barcode. b Alternatively, gRNAs can be modified to include a poly-A sequence or other type of capture sequence to allow direct gRNA detection via poly-T priming or via the capture sequence. c After single-cell encapsulation, cDNA and gRNAs are captured by oligos on gel beads, with subsequent preparation of sequencing libraries for NGS (hU6 = human U6 promoter, EF1a = human elongation factor 1 alpha promoter, WPRE = Woodchuck Hepatitis virus posttranscriptional regulatory element, ΔNGFR = truncated nerve growth factor receptor, LTR = long terminal repeat, CS = capture sequence, CBC = cell barcode, UMI = unique molecular identifier)