NR AWLB
AU Nonno,R.; Esposito,E.; Vaccari,G.; Bandino,E.; Contel,M.; Chiappini,B.; Marcon,S.; Di Bari,M.; Benestad,S.L.; Agrimi,U.
TI NOR98 shows molecular features reminiscent of GSS
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 PR-26
PT Konferenz-Poster
AB
Molecular variants of PrPsc are being increasingly investigated in sheep scrapie and are generally referred to as "atypical" scrapie, as opposed to "classical scrapie". Among the atypical group, Nor98 seems to be the best identified.
We studied the molecular properties of Italian and Norwegian Nor98 samples by WB analysis of brain homogenates, either untreated, digested with different concentrations of proteinase K, or subjected to enzymatic deglycosylation. The identity of PrP fragments was inferred by means of antibodies spanning the full PrP sequence.
We found that undigested brain homogenates contain a Nor98-specific PrP fragment migrating at 11 kDa (PrP11), truncated at both the C-terminus and the N-terminus, and not N-glycosylated. After mild PK digestion, Nor98 displayed full-length PrP (FL-PrP) and N-glycosylated C-terminal fragments (CTF), along with increased levels of PrP11. Proteinase K digestion curves (0,006-6,4 mg/ml) showed that FL-PrP and CTF are mainly digested above 0,01 mg/ml, while PrP11 is not entirely digested even at the highest concentrations, similarly to PrP27-30 associated with classical scrapie. Above 0,2 mg/ml PK, most Nor98 samples showed only PrP11 and a fragment of 17 kDa with the same properties of PrP11, that was tentatively identified as a dimer of PrP11. Detergent solubility studies showed that PrP11 is insoluble in 2% sodium laurylsorcosine and is mainly produced from detergent-soluble, full-length PrPsc.
Furthermore, among Italian scrapie isolates, we found that a sample with molecular and pathological properties consistent with Nor98 showed plaque-like deposits of PrPsc in the thalamus when the brain was analysed by PrPsc immunohistochemistry. Taken together, our results show that the distinctive pathological feature of Nor98 is a PrP fragment spanning amino acids ~ 90-155. This fragment is produced by successive N-terminal and C-terminal cleavages from a full-length and largely detergent-soluble PrPsc, is produced in vivo and is extremely resistant to PK digestion. Intriguingly, these conclusions suggest that some pathological features of Nor98 are reminiscent of Gerstmann-Sträussler-Scheinker disease.
AD R. Nonno, E. Esposito, G. Vaccari, M. Conte, B. Chiappini, S. Marcon, M. di Bari, U. Agrimi: Istituto Superiore di Sanità, Department of Food Safety and Veterinary Public Health, Rome, Italy; E. Bandino: Istituto Zooprofilattico della Sardegna, Sassari, Italy; S.L. Benestad: National Veterinary Institute, Department of Pathology, Oslo, Norway
SP englisch
PO Italien