Figure 1.

SlugCas9-KH and OgeuIscB nickases do not induce the contraction of CAG/CTG repeats. (A) GFP-based assay used to detect contraction of the CAG repeats length. The repeat interferes with the splicing of the reporter in a size-dependent manner with longer repeats inducing more missplicing and lower GFP expression. (B) Timeline experiment for the GFP-based assay to detect CAG contractions. (C) Western blots of GFP(CAG)₁₀₁ cells transfected with SpCas9D10A, SlugCas9-KH D10A, and OgeuIscB E193A. Full uncropped blots are found in Supplementary Fig. 7. (D) Cartoon of the sgRNAs used together with the SlugCas9-KH. (E) Percentage of GFP positive cells for each sgRNA. Dashed lines represent the gate containing the brightest 1% of the cells transfected with Cas9 only. Previous work²⁹ has shown that this population is enriched in shorter repeats. (F) Cartoon of the ω-RNAs targeting the CAG/CTG repeat. (G) Percentage of GFP positive cells for each sgRNA. Dashed lines represent the gate containing the brightest 1% of the cells transfected with Cas9 only. Previous work²⁹ has shown that this population is enriched in shorter repeats.