PRNP and prion disease: On the other hand, there are transgenic mouse models that overexpress bovine, ovine, cervid, or human PrP, which replicate prions of the respective species and develop a clinical prion disease with known and predictable incubation times (Buschmann et al. 2000; Vilotte et al. 2001; Browning et al. 2004; Wadsworth et al. 2010).