Fig 2: Multi-organ H&E staining shows expected tissue architecture and appearance in Stx6−/− and Stx6+/− mice which lack consistent tissue-intrinsic pathologies.The following organs were harvested from Stx6+/+ (n = 5), Stx6+/ - (n = 5) and Stx6−/− (n = 4) female mice at 56–61 weeks of age: liver, pancreas, kidney, skeletal muscle and white adipose. These were formalin fixed, processed to paraffin and underwent haematoxylin and eosin (H&E) staining, revealing no consistent differences between genotypes. Scale bar corresponds to 120 μm (a-l), and 500 μm (m-o).

Fig 3: Knockout of Stx6 does not alter PrP deposition in prion infected mice.Immunohistochemistry using anti-PrP antibody ICSM35 in whole brain (left) with schematic depiction of PrP deposition (right; pink shading: moderate PrP deposition; red shading: intense PrP deposition; red dots: PrP micro-plaques) or representative images from striatum, cortex and midbrain (middle) from Stx6−/−, Stx6+/− and Stx6+/+ mice inoculated with PBS (top) or ME7 (middle) and RML (bottom) mouse-adapted scrapie prions, shows expected PrP deposition in all prion-inoculated samples at end-point, with widespread diffuse staining for both strains and additional presence of micro-plaques with ME7 (yellow arrows). There was no evidence of spontaneous PrP deposition in control animals or gross difference evident between genotypes. Scale bar corresponds to 100 μm in the high-power magnification and 1.8 mm for the overview images. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig 4: Incubation periods in mice with Stx6 reduction following intracerebral inoculation with RML and ME7 mouse-adapted scrapie prions.(A-D) Kaplan-Meier curve of survival probability following intracerebral inoculation of Stx6−/− (red), Stx6+/− (grey) and Stx6+/+ (blue) C57BL/6N mice (n = 20 per group) with 1% brain homogenate from (A,B) RML and (C,D) ME7 infected C57BL/6N mice. (A, C) Survival probability until animals were culled due to scrapie sickness shows a 12-day increase in median incubation period for (A) Stx6−/− and Stx6+/− mice following RML inoculation (significant only for Stx6+/− animals) and (C) for Stx6−/− mice only following ME7 inoculation relative to Stx6+/+ mice. (B,D) Disease-free survival probability (time until onset of the first scrapie symptom) (B) does not show a significant association with Stx6 genotype following RML-inoculation but (D) a 7-day increase in Stx6−/− mice inoculated with ME7, relative to Stx6+/+ mice. Significance shown from pair-wise log-rank test for Stx6−/− (red asterix) and Stx6+/− (black asterix) mice relative to wildtype controls (** P > 0.01; *** P > 0.001). Median incubation period shown below each plot. Crosses indicate censored animals. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig 5: Neuronal loss and spongiform change were comparable in end-stage Stx6−/−, Stx6+/− and Stx6+/+ mice.Haematoxylin and eosin (H&E) staining of whole brain (left) with schematic depiction of spongiosis (right; light purple shading: widely dispersed mild spongiosis; darker purple shading: moderate spongiosis; yellow shading: neuronal loss) and representative images from striatum, cortex and midbrain (middle) from Stx6−/−, Stx6+/− and Stx6+/+ mice inoculated with PBS (top) or ME7 (middle) and RML (bottom) mouse-adapted scrapie prions shows expected spongiform pathology in all samples at end-point, including mild hippocampal neuronal loss with ME7, with no gross differences evident between genotypes. No neuropathology was evident in PBS-inoculated controls. Scale bar corresponds to 100 μm in the high-power magnification and 1.8 mm for the overview images. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)