NR AWIM
AU Kupfer,J.; Proft,J.; Eiden,M.; Buschmann,A.; Groschup,M.H.
TI The influence of amino acid substitutions and different TSE agents with regard to the convertibility of the prion protein in a cell-free assay
QU International Conference - Prion 2006: Strategies, advances and trends towards protection of society - 3.10.-6.10.2006, Torino, Italy, Lingotto Conference Centre - Poster sessions S-14
PT Konferenz-Poster
AB The crucial event in the pathogenesis of prion diseases or transmissible spongiform encephalopathies (TSEs) is an induced conformational change of cellular PrPc into an abnormal form which is designated PrPsc. This process is also called conversion and leads to modified biochemical properties of abnormal prion protein such as a partial resistance to proteinase K, aggregation and subsequent fibril formation. However, the molecular mechanism underlying this structural transition remains unknown. In a cell-free assay the conversion reaction can be mimicked by incubating highly purified recombinant PrPc molecules together with PrPsc seeds in an appropriate conversion buffer. Under these conditions we can show, that PrPsc itself can induce the conversion of PrPc into a partially proteinase K resistant form designated PrPres. This newly converted PrPres can be selectively detected by an antibody that reacts to an epitope tag which is absent in the seed derived PrPsc. In our assay we use procaryotically expressed PrPc as a substrate and mouse passaged scrapie strains/isolates as seeds. Experiments were carried out using chimerical constructs, which consisted either of murine and ovine PrPc or of murine and bovine PrPc. The chimerical proteins were incubated with three different mouse scrapie strains and with mouse BSE. The experimental data show that even single or few amino acid substitutions within the prion protein have a major effect on its conversion. Additionally, the reaction also depends on the PrPsc seed, which is used to induce the misfolding. Interestingly, these results are generally in line with in-vivo data which were obtained in transgenic mice carrying the chimerical PrPcs.
AD Institute for Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institute, Federal Research Institute for Animal Health, Insel Riems, Germany. E-mail: martin.gropschup@fli.bund.de
SP englisch
PO Italien