Overexpression of chimeric murine/ovine PrP (A136H154Q171) in transgenic
mice facilitates transmission and differentiation of ruminant prions
Peter C. Griffiths1, Jane M. Plater, Alun Chave, Dhanushka Jayasena, Anna
C. Tout, Paul B. Rice, Christopher M. Vickery, John Spiropoulos, Michael J.
Stack and Otto Windl + Author Affiliations
Animal Health and Veterinary Laboratories Agency ↵1 E-mail:
peter.griffiths@ahvla.gsi.gov.uk Received 14 January 2013. Accepted 3 June 2013.
Abstract
Development of transgenic mouse models expressing heterologous prion
proteins (PrP) has facilitated and advanced in vivo studies of prion diseases
affecting humans and animals. Here, novel transgenic mouse lines expressing a
chimeric murine/ovine (Mu/Ov) PrP transgene, including amino acid residues
alanine, histidine and glutamine at ovine polymorphic codons 136, 154 and 171
(A136H154Q171), were generated to provide a means of assessing the
susceptibility of the OvPrPAHQ allele to ruminant prion diseases in an in vivo
model. Transmission studies showed that the highest level of transgene
overexpression, in Tg(Mu/OvPrPAHQ)EM16 mice, conferred high susceptibility to
ruminant prions. Highly efficient primary transmission of atypical scrapie from
sheep was shown, irrespective of donor sheep PrP genotype, with mean incubation
periods (IPs) of 154-178 days post-inoculation (dpi), 100% disease penetrance,
and early Western blot detection of protease-resistant fragments (PrPres) of the
disease-associated isoform, PrPSc, in Tg(Mu/OvPrPAHQ)EM16 brain from 110 dpi
onwards. Tg(Mu/OvPrPAHQ)EM16 mice were also highly susceptible to classical
scrapie and BSE, with mean IPs 320 and 246 days faster, respectively, than
wild-type mice. Primary passage of atypical scrapie, classical scrapie and BSE
showed that the PrPres profiles associated with disease in the natural host were
faithfully maintained in Tg(Mu/OvPrPAHQ)EM16 mice and were distinguishable based
on molecular masses, antibody reactivities and glycoform percentages.
Immunohistochemistry was used to confirm PrPSc deposition in brain sections from
terminal phase TSE-challenged Tg(Mu/OvPrPAHQ)EM16 mice. The findings indicate
that Tg(Mu/OvPrPAHQ)EM16 mice represent a suitable bioassay model for detection
of atypical scrapie infectivity and offer the prospect of differentiation of
ruminant prions.
Thursday, June 13, 2013
Experimental interspecies transmission studies of the transmissible
spongiform encephalopathies to cattle: comparison to bovine spongiform
encephalopathy in cattle
TSS
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