Figure 1. Kinetics of Sho down-regulation in scrapie-infected wt Prnp ^a/a mouse brain.

a) Time-course of reduction of mature full-length 22 kDa Shadoo protein (mSho) in Prnp ^a/a mice inoculated with RML scrapie prions and analyzed at the indicated days post-inoculation (06rSH1 antibody). Pair-wise analyses are shown horizontally where “H” designates healthy negative control mice inoculated with control brain whereas “S” designates mice inoculated with the RML isolate of scrapie prions. Glyceraldehyde phosphate dehydrogenase (GAPDH) blot demonstrates similar protein loading for “H” and “S” samples. Western blot analyses show Sho levels in untreated brain samples whereas levels of PrP^Sc were assessed after PK digestion performed prior to sample electrophoresis and immunoblotting with D18 antibody. Brain histoblot analyses of protease-resistant PrP (D18 antibody) for three mice at the 150-day time-point are shown below the gel analysis, marked “PrP^Sc”, to demonstrate reproducibility of the protein accumulation. b) Graphical representation of Sho and PrP^Sc levels in RML-inoculated animals with Sho normalized to 100% for the day 42 time-point in the preclinical phase of disease and with PrP^Sc normalized to 100% for the day 150 time-point in the clinical phase of disease. In both cases half-maximal change occurred approximately 50 days before the experiment endpoint and at ∼65% elapsed time in disease incubation period.