Disparity in subcellular fraction PrPres levels and relative infectivity in vitro and in vivo. (A) Relative amounts of PrPres contained within MoRK13-inf fractions (dot blot - top panel, also Figure 2; red line) plotted against relative infectivity of each fraction (PrPres produced by recipient MoRK13 - bottom panel, also Figure 3; blue line). There is a highly significant separation of relative PrPres and infectivity levels observed in fraction #8; statistical analysis was by two way ANOVA; *** p < 0.001. Fractions enriched in lipid raft (LR), endoplasmic reticulum (ER), mitochondrial (MT) and early endosome (EE) marker proteins are highlighted. (B) Mean survival (horizontal bar) of Tga20 mice inoculated with 0.01% (w/v in PBS) M1000 brain homogenate, whole cell lysate from MoRK13 and MoRK13-inf cells, and selected subcellular fractions from MoRK13-inf. Each data point represents the number of days post-inoculation (PI) that a terminally ill mouse was sacrificed, with the exception of Tga20 mice inoculated with MoRK13 cell lysate (#) which were symptom free when culled at 245 days PI. Mice inoculated with 0.01% (w/v) M1000 brain homogenate had a significantly shorter incubation period than those exposed to all other inocula. Mice inoculated with fraction #10 had a significantly longer incubation period compared to mice exposed to all other infectious inocula. Statistical analysis was by one way ANOVA; *** p < 0.001.