NR AXTV
AU O'Rourke,K.; Spraker,T.R.; Greenlee,J.J.; Gidlewiski,T.E.; Hamir,A.N.
TI Prolonged Incubation Time and Differential Processing of PrP-CWD in Experimentally Infected Rocky Mountain Elk Lacking the 132M Prnp Allele
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Protein Misfolding P01.44
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB
Background: The relationship between host Prnp genotype, susceptibility, and incubation time varies among the ruminant prion diseases, including chronic wasting disease (CWD). The Rocky Mountain elk Prnp gene encodes a nonsynonymous mutation at codon 132, resulting in substitution of leucine (L) for methionine (M). A polymorphism at the corresponding site (codon 129) is associated with varying patterns of susceptibility in human prion diseases. We have previously established the predisposition to CWD in homozygous 132MM elk in captivity and the approximate doubling of incubation time in heterozygous 132LM elk following oral challenge.
Objective: We have now defined the prolonged incubation time in 132LL elk to be approximately triple that of MM132 elk. To examine potential mechanisms for the prolonged incubation period, PrP-CWD from elk of the short (132MM), intermediate (132LM) and long (132LL) incubation phenotypes was characterized. Methods: The protease resistant core of PrP-CWD from brain of experimentally infected elk of each of the three genotypes was examined by Western blot analysis using amino-terminus (ab P4) and carboxyl-terminus (ab F99/97) antibodies, with and without proteinase K (PK) digestion, and with and without deglycosylation.
Results: Western blot analysis and antibody epitope mapping of PK-digested PrP-CWD demonstrated a reduction in the apparent molecular weight and loss of the antibody P4 epitope in the PK-resistant core of PrP-CWD from 132LL elk and a significant increase in the ratio of unglycosylated to glycosylated isoforms of PrP-CWD in these samples.
Discussion: Differential glycosylation and altered folding of PrP-CWD in 132LL elk suggest that intracellular processing of PrP-CWD may be one of the mechanisms associated with the prolonged incubation period associated with the polymorphism.
AD K. O'Rourke, Agricultural Research Service, USDA, Animal Disease Research Unit, USA; T.R. Spraker, Colorado State University, USA; J.J. Greenlee, A.N. Hamir, NADC, USA; T.E. Gidlewiski, VS, USA
SP englisch
PO Schottland