Fig. 1

A fluorescent reporter detects base editing activity. a Diagram of the BE-FLARE reporter comprised of a modified BFP (BFP) and gRNA sequence used to transition BFP to GFP through base editing (BE). Codon 66 (CAC) encoding histidine is targeted and converted to tyrosine (codons TAT or TAC), resulting in GFP expression. Codon conversion to CAT is synonymous for His, thus the protein remains as BFP. b BFP to GFP conversion in HEK293 and PC9 cells. Cells were co-transfected with the BE-FLARE and a plasmid expressing BE3 and either a non-targeting guide (NT-BE) or a BFP targeting guide (BFP-BE). BFP and GFP positive cells were quantified by flow cytometry 72 h after transfection. Data are representative of three independent experiments. c PC9 cells from the experiment described in (b) were sorted based on BFP (unedited) or GFP fluorescence. Five days later, DNA was extracted for amplicon sequencing of the BFP locus. Data represent a gene browser view of aligned reads in IGV and are representative of two independent experiments. Raw data can be found in Additional file 2