Differential expression of Prnp and Sprn in scrapie infected sheep also reveals Prnp genotype specific differences

The central role for PrP in the pathogenesis of the transmissible spongiform encephalopathies (TSEs) is illustrated by the resistance of Prnp0/0 mice to disease and by the inverse association of Prnp gene dosage with incubation period. Understanding the role of PrPC in TSEs necessitates knowledge of expression levels of the Prnp gene during the development of disease. SSBP/1 scrapie shows a defined pattern of disease progression and here we show that Prnp and shadow of PrP (Sprn) are differentially expressed in different brain areas and lymphoid tissues. Counter-intuitively we found that there is no positive correlation between expression of Prnp or Sprn and patterns of disease progression. Prnp and Sprn expression levels are both influenced by Prnp genotype; although the scrapie-sensitive VRQ/VRQ sheep did not express the highest level of either. In addition, infection with SSBP/1 scrapie seems to have little effect on either PrP or Shadoo expression levels.