PRNP and scrapie: Using recombinant ovine PrP fragments [ovPrP (25–234)], corresponding to scrapie-resistant and susceptible genotypes (Ala136/Arg154/Gln171, ARR and Ala136/Arg154/Arg171, ARQ, respectively), it was confirmed that, in contrast to what observed for the transmission of TSE, PrP-ARR was much more toxic for neurons in culture than PrP-ARQ, due to the lower structural stability that reduced the ability to form large aggregates and fibrils [97].