Unraveling the key to the resistance of canids to prion diseases
A. PrP amino acid alignment based on residues 91–230 (dog PrP numbering) from species with different experimental and/or natural susceptibilities to prion diseases. Classification criteria were based on the number of representative prion strains able to be transmitted and cause disease in the host. Identical amino acids are indicated by dots. Δ: number of different amino acids compared to dog PrP. Note the similarity of the amino acid sequence in the cat (highlighted in red), a species known to be susceptible to naturally acquired prion disease. B. Upper line, dog amino acid residues 91–230. The 6 amino acid differences compared to cat PrP sequence are highlighted by red squares. Boxes show each highlighted amino acid and representative species in which the particular amino acid is present also. Where prion susceptibility of the species has been proven the reference is provided. NP: susceptibility not proven. Positions 101 and 163 are polymorphic in dogs (Ser/Gly and Asp/Glu, respectively). Species codification and accession numbers: doPrP, dog PrP (FJ870767.1); hoPrP, horse PrP (ACG59277); raPrP, rabbit PrP (NP001075490); poPrP, porcine PrP (AAA92862.1); caPrP, cat PrP (ACB97675.1); huPrP, human PrP (NP001073592); mdPrP, mule deer PrP (AY330343.1); moPrP, mouse PrP (NP035300); boPrP, bovine PrP (ABR92636.1); ovPrP, ovine PrP (NP001009481.1); bvPrP, bank vole PrP (AAL57231.1); ahPrP, armenian hamster PrP (AAA37014); rcPrP, raccoon PrP (ACA50738.1); rsPrP, red squirrel PrP (AAN16491); coPrP, coyote PrP (AGA63673); gwPrP, grey wolf PrP (AGA63687); rfPrP, red fox PrP (ACA50742); huPrP; human PrP (U29185.1); niPrP, nilgai PrP (AAV30507); baPrP, California big-eared bat (AAN16503); anPrP, anteater PrP (AAN16516).