a, Sequence and location of the Cas9 gM (mouse) and gMH (mouse and human) target sites in the endogenous mouse Pcsk9 gene and human PCSK9 transgene inserted at the mouse Rosa26 locus. The single base position that differs between the gMH target sites in the mouse Pcsk9 gene and the human PCSK9 transgene is highlighted in red. Blue bars indicate exons for the mouse genomic region and purple bars represent exons for the human genomic locus; the PAM sequence for the sites is in bold and the spacer sequence is underlined. b, Surveyor assay and next-generation DNA sequencing data demonstrate efficient in vivo modification of the on-target endogenous mouse Pcsk9 site and human PCSK9 transgene in mouse liver. Assays were performed at day 4 and at week 3 after administration of adenoviral vectors that encode gM and Cas9 (gM), gMH and Cas9 (gMH) or GFP and Cas9 (GFP) using genomic DNA isolated from livers of n = 3 biologically independent wild-type and knock-in mice. Asterisks indicate the cleaved PCR products expected following treatment with Surveyor nuclease. Percentages show the frequencies of indel mutations determined by targeted amplicon sequencing using next-generation sequencing; these are the same values shown for the on-target sites in Fig. 3 and Extended Data Fig. 7. Lines divide lanes taken from different locations on the same gel. For source data for Surveyor assays, see Supplementary Fig. 1. For source data for targeted amplicon sequencing, see Supplementary Tables 6 and 7 for gM and gMH, respectively. b, Mouse Pcsk9 protein levels measured in plasma in n = 3 biologically independent wild-type and knock-in mice, and human PCSK9 protein levels measured in plasma in n = 3 biologically independent knock-in mice after CRISPR–Cas nuclease treatment. Protein levels in plasma were assessed at day 4, 7 and week 3 after the administration of gM, gMH or control GFP adenoviral vectors and normalized to baseline levels at each time point. Significant differences between groups were determined using two-way ANOVA and Dunnett’s two-sided adjusted multiple comparisons test; *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. See Source Data for exact adjusted P values. Values are presented as group means, error bars represent standard errors of the mean. Source data