Protease-Sensitive Synthetic Prions (original) (raw)
Figure 1
Tg9949 mice are prone to neurological dysfunction but do not spontaneously generate prions.
(A) Wild-type (FVB), Tg4053, and Tg9949 mice were monitored for signs of neurological dysfunction for >900 days. Both uninoculated and BSA-inoculated Tg9949 mice were more likely than wt mice (p = 0.03) and Tg4053 mice (p<0.001) to develop neurological dysfunction. However, prions could not be detected in the brains of neurologically impaired Tg9949 mice, as determined by bioassay in Tg9949 and Tg4053 mice (B), by histopathological staining (C), by Western immunoblotting (D), and by the amyloid seeding assay (E). (C) Brain sections of neurologically impaired Tg9949 mice were stained with H&E to visualize vacuoles (left), α-GFAP to visualized astrocytic gliosis (middle), and α-PrP to visualize PrPSc deposits (right). Scale bars represent 100 µm. Mol, molecular cell layer; GC, granular cell layer; WM, white matter. Additional neuropathological analyses of control brains are shown in Fig. S1. (D) Western immunoblots of undigested and PK-digested brain samples from six aged Tg9949 mice show no rPrPSc. Homogenate from a Tg9949 mouse inoculated with RML prions is shown as a positive control. Lane assignments are as indicated in panel E. (E) Brain samples from six aged Tg9949 mice do not seed the formation of recPrP amyloid, as judged by an increase in Thioflavin T fluorescence (top) and by a decrease in the lag phase for amyloid formation (bottom). An uninoculated FVB mouse brain is included as a negative control. Negative controls in (A) are pooled results, including some previously published data [27].