Extended Data Fig. 4: Optimization of base editing in HSPCs.

a, Sequences of sgRNA-49 and of sgRNA-49.2 to 49.8 tiled along the K352 codon. The classical base editing window (position 4-8) is highlighted in blue and the intended A > G on-target is in bold green for each sgRNA. b, Flow cytometry of human CD34+ HSPCs base edited with ABE8e-SpRY mRNA and each sgRNA from (a) (12 days post-electroporation). c, Next generation sequencing of HSPCs 5 days after electroporation with ABE8e-SpRY mRNA and different sgRNAs. CRISPResso plots depict a 60 base pairs region, comprising 30 bases flanking upstream and downstream from the center of each sgRNA (aligned to sgRNA-49.3 for sgRNA-NTC). The quantification of base conversions is set on a 30 base pairs window, with 15 bases flanking upstream and downstream from the center of each sgRNA (aligned to sgRNA-49.3 for sgRNA-NTC). NGS reads accounting for less than 0.8% of total reads were classified as “Others”. d, Summary of amino acid conversions at positions N351, K352, and E353 across different sequencing profiles depicted in (c) for sgRNA-NTC, sgRNA-49, and sgRNA-49.3.