Figure 4.

Surrogate Cre-mediated recombination using Cre2^GO BE reporter. (A) (top) Schematic of all-in-one Cre recombinase GO reporter with (i) modified 5′ end in the Cre-recombinase cDNA to include silent start site ‘ACG’, (ii) sgGO and (iii) an endogenous targeting sgRNA (Cre^GO). (bottom) Schematic of modified Cre^GO reporter with masked, synonymous alternative start sites (Cre2^GO). (B) Flow cytometry of immortalized MEFs containing an R26-LSL-tdTomato allele expressing FNLS-P2A-GFP or no editor and Cre^GO or Cre2^GO reporters. FNLS expressing cells were gated on tdTomato⁺ cells within the GFP⁺ population. WT cells are gated on tdTomato⁺ cells. (C) R26-LSL-tdTomato MEFs expressing FNLS and Cre2^GO with sgRNA targeting endogenous Ctnnb1.S33 or no sgRNAwere sorted for tdTomato expression. Sanger sequencing chromatograms are displayed for the bulk and sorted populations at the Ctnnb1.S33 locus. (D) Deep sequencing analysis of C>T edits at the Ctnnb1.S33 locus in MEFs described in C.