Unexpectedly, we found that chimeric PrPs that lack BVPrP residues E227 and S230 function as better substrates for cross-species prion replication than wild-type BVPrP, based on the higher levels of PrPres observed following infection with hamster or mouse prions (Figs 1C–1E, 1G-1I, 3C, 3D, 3F, 3G and 4D–4F). This evidence concerns the gene MSMB and infection.