Moreover, the ability of the Q172R mutant to inhibit hamster prion formation in a purified system even when WT HaPrP substrate was pre-incubated with both poly(A) RNA and scrapie template suggests that mutant PrP inhibits the conversion of WT PrP by blocking a nascent seeding site (NSS) on newly formed, PMCA-generated PrPSc molecules (Figure 7). Here, PRNP is linked to scrapie.