(A) Representative fluorescence microscopy images of EM48 and DAPI stained cryostat sections of the CA1 region of the hippocampus in R6/2 transgenic and R6/2-UBQ1 double transgenic mouse at 6 weeks, 9 weeks and following end-stage euthanasia. Bar = 15 µm. (B) Similar to A, but showing representative sections from the dentate gyrus in end-stage mice. Bar = 15 µm. (C) Quantification of htt inclusions >0.5 µm in size in the CA1 region of the hippocampus at 6 weeks, 9 weeks and end-stage R6/2 and R6/2-UBQ1 double transgenic mice. The R6/2-UBQ1 double transgenic mice contained 22% fewer inclusions than R6/2 mice at 6 weeks (p = 0.04), but not at the other times. (D) Quantification of htt inclusions >1 µm in size in the CA1 region of the hippocampus at 6 weeks, 9 weeks and end-stage R6/2 and R6/2-UBQ1 double transgenic mice. The R6/2-UBQ1 double transgenic mice had 40% fewer inclusions at 9 weeks compared to R6/2 transgenic mice (p = 0.027). (E and F) Similar to B and C, but showing htt inclusions in the cortex. R6/2-UBQ1 double transgenic mice had 8.5% fewer inclusions greater than 0.5 µm at the end-stage of disease. (G, H) Similar to E and F, but comparing inclusions in the striatum. There was no difference in the number of inclusions in the striatum between the two genotypes at any time point.