TRANSMISSIBLE MINK ENCEPHALOPATHY SPECIES BARRIER EFFECT BETWEEN FERRET AND MINK - PRP GENE AND PROTEIN-ANALYSIS

Experimental infection of transmissible mink encephalopathy (TME) in t wo closely related mustelids, black ferret (Mustela putorius furo) and mink (Mustela visa), revealed differences in their susceptibility to the TME agent. When challenged with the Stetsonville TME agent, a long er incubation period was observed in ferrets (28 to 38 months) than mi nk (4 months). Western blot analysis of ferret and mink prion proteins (PrP) demonstrated no detectable differences between the proteins. No rthern blot analysis of ferret brain RNA indicated that PrP mRNA abund ance is similar in infected and uninfected individuals. We amplified t he PrP coding region from ferret DNA using the polymerase chain reacti on and compared the deduced amino acid sequence of the ferret PrP gene with the mink PrP gene. This comparison revealed six silent base chan ges and two amino acid changes between mink and ferret: Phe --> Lys at codon 179 and Arg --> Gln at codon 224, respectively. These changes m ay indicate the region of PrP that is responsible for the species barr ier effect between mink and ferret.