NR AOQD
AU Baskakov,I.V.
TI In vitro conversion of recombinant prion protein into a fibrillar form displays species-specificity
QU International Conference - Prion diseases: from basic research to intervention concepts - TSE-Forum, 08.10.-10.10.2003, Gasteig, München - Poster session - BR-105
PT Konferenz-Poster
AB
The transmission of prions across species is limited due to a species barrier. While efficient transmission requires identity or high homology between the amino acid sequences of PrPc and PrPsc isoforms, individual conformational properties of PrPsc strains may affect significantly the ability of prions to cross the species barrier. Considering conformational diversity of existing strains and the possibility of emergence of new strains in future, it would be difficult to predict the intrinsic propensity of prions to cross the transmission barrier between animals and human.
In our previous study, we developed an experimental procedure for spontaneous conversion of recombinant PrP (recPrP 90-231) into a fibrillar form in the absence of PrPsc. The fibrillar isoform of recPrP formed spontaneously was similar to "prion rods" as judged by electron microscopy and shared important conformational properties with PrPsc. Recently we found that transmission of a small aliquot (a seed) from a mature conversion reaction to a fresh reaction substantially shortened the lag phase of the fibril formation. This phenomenon is often referred to as seeding. Furthermore, we observed that the conversion of human recPrP90-231 can be induced by seeding with pre-formed fibrils of human recPrP90-231, but not with fibrils of mouse recPrP 89-231. When the conversion reaction in human a-recPrP 90-231 was seeded with fibrils of human recPrP, the co-presence of mouse a-recPrP 89-230 (the molar ratio of mouse to human recPrP 1:4) inhibited the conversion. These data demonstrated that conversion of recPrP in vitro displays species-specificity in the absence of cellular environment and recapitulates peculiar properties of prion propagation in vivo. We speculate that the in vitro conversion system may be used as a rapid assay for assessing the intrinsic propensities of prion transmission between different mammalian species.
AD Ilia V. Baskakov, Medical Biotechnology Center, University of Maryland Biotechnology Institute, Baltimore, USA; Department of Biochemistry, University of Maryland, Baltimore, USA
SP englisch
PO Deutschland