Fig. 2. RNA-encoded ABE restores CFTR function in human lung airway cells with W1282X mutation.

a Expression of GFP plasmid and mRNA in CFF-16HBEge W1282X cells. Twelve hours of post electroporation, bright field and fluorescence images were taken. Scale bar = 100 µm. b Protospacer sequence used to base edit W1282X. The pre-mature stop codon is highlighted in yellow. PAM sequence is underlined. Target “A9” is red and bystander “A5” is blue. c A-to-G conversion rate in W1282X cell pools electroporated with moderately modified sgRNA and either unmodified (unmodified-6.3) or modified (5moU-6.3) ABE mRNA. Data represent mean ± SD (n = 3 (unmodified-6.3), n = 4 (5moU-6.3) biologically independent experiments). *P = 0.0456. d CFTR protein expression in 5moU-6.3-treated W1282X cell pools by western blot. GAPDH is loading control. Experiments were done for three times, and one is shown. e CFTR protein expression in three single cell clones. f Genotypes of cell clones. Clone 1 has a bystander editing. Clone 3 has base editing only on the SV40 disrupted CFTR allele. g ABE restored CFTR-mediated Cl- transport in clones 1 and 2. Values of area under the curve (AUC) in h is shown. Data represent mean ± SD (n = 3 wells of cells examined in one experiment). N.S. not significant (two tailed t-test). h Representative traces from electrophysiology assays. Source data are provided as a Source Data file for c–e.