Figure 1.

Schematics of Fah gene and viral vectors used. (A) Fah^−/− mouse gene locus. The hereditary tyrosinemia type 1 (HT1) mutation is on the last nucleotide of exon 8, as shown in red. The protospacer adjacent motif (PAM) sequence for the indicated guide RNA is highlighted in blue. (B) Adeno-associated virus (AAV) vector homology template with 1.2 kb homology fragment flanked by inverted terminal repeats. The corrected Fah gene sequence is shown in red, and the PAM sequence, which is modified to prevent re-cutting, is shown in blue. (C) The LV-Cas9 vector contains a single-guide RNA (gRNA) under the control of the U6 promoter. Cas9 from Streptococcus pyogenes is co-expressed with green fluorescent protein (GFP) under the control of the EFS promoter by means of a P2A cleavage site.