Semiautomated cell-free conversion of prion protein: Applications for high-throughput screening of potential antiprion drugs

Transmissible spongiform encephalitis (TSE) is a lethal illness with no known treatment. Conversion of the cellular prion protein (PrPC) into the infectious isoform (PrPSc) is believed to be the central event in the development of this disease. Recombinant PrP (rPrP) protein folded into the amyloid conformation was shown to cause the transmissible form of prion disease in transgenic mice and can be used as a surrogate model for PrPSc. Here, we introduced a semiautomated assay of in vitro conversion of rPrP protein to the amyloid conformation. We have examined the effect of known inhibitors of prion propagation on this conversion and found good correlation between their activity in this assay and that in other in vitro assays. We thus propose that the conversion of rPrP to the amyloid isoform can serve as a high-throughput screen for possible inhibitors of PrPSc formation and potential anti-TSE drugs.