Paradoxical shortening of scrapie incubation times by expression of prion protein transgenes derived from long incubation period mice

Prolonged incubation times for experimental scrapie in ILnJ mice are dictated by a dominant gene linked to the prion protein gene (Prn-p). Transgenic mice were analyzed to discriminate between an effect of the ILnJPrn-pb allele and a distinct incubation time locus designated Prn-i. Paradoxically, 4 independent Prn-pb transgenic mouse lines had scrapie incubation times shorter than nontransgenic controls, instead of the anticipated prolonged incubation periods. Aberrant or over-expression of the Prn-pb transgenes may dictate abbreviated incubation times, masking genuine PrnpPrn-i congruence; alternatively, a discrete Prn-i gene lies adjacent to Prn-p.