Fig. 5. Truncation of mutant HTT in the striatum of adult HD140Q KI mice.

a mEM48 western blotting showing age-dependent decrease of soluble mutant exon 1 HTT and corresponding increase of aggregated HTT in the HD KI striatum. Quantification of western blotting results is also shown. Data are presented as mean values ± SEM and were obtained from three independent experiments each mouse (n = 3 mice per genotype, **p < 0.01, ***p < 0.001, one-way ANOVA followed by Tukey’s multiple comparison tests, aggregated HTT/vinculin analysis, F = 19.79, p = 0.0023; mutant exon 1 HTT/vinculin analysis, F = 49.81, p = 0.0002). b HD140Q KI mice were crossed with Cas9 mice to yield KI/Cas9 mice. AAV HTT-gRNA was then injected into the striatum of KI/Cas9 mice at 2 months of age. Eight weeks after injection, the striatum of the injected mice was isolated for analyzing truncated HTT. c A fluorescent image of the injected mouse striatum verifying the viral transduction of AAV HTT-gRNA that also expresses red fluorescent protein (RFP). Scale bar: 20 μm. d T7E1 analysis of the HTT DNAs from the injected region confirming that the only HTT-gRNA, but not control gRNA, could target the HTT gene to generate fragmented DNA products. e Western blotting analysis of striatum lysates of AAV-injected mice showing that truncation of mutant HTT at exon 2 and exon 13 by HTT-gRNAs (HTT-91 gRNA and HTT-571 gRNA) could reduce full-length mutant HTT and increase exon 1 HTT but did not alter the amount of aggregated HTT. f mEM48 immunostaining of the AAV-injected striatum of HD140Q KI mice showing that nuclear HTT accumulation after AAV HTT-gRNA injection is not different from that with the AAV control gRNA injection. Scale bar: 20 μm. More than three times of experiments were performed independently for c–f. Source data are provided as a Source Data file.