Figure 3: CRISPR/Cas9-mediated deletion of the mHtt promoter region reduces SI in Htt’s CAG repeat tract.

A) Cartoon indicating the location of the gRNA pair referred to as “QPro,” spanning an approximately 1,200bp region, that targets unique sequences in the humanized Htt^Q111 allele that are not present in mouse Htt. B) AAV8-delivered treatment with QPro results in robust, allele-selective lowering of HTT protein in the livers of Htt^Q111+; Cas9 ⁷³ mice. C) Treatment with AAV8::QPro at 2.5 months of age results in reduction of expansion index at 8 months of age. D) Exemplar traces of CAG tract expansions in untreated and treated animals.