Serial transmission in rodents of neurodegeneration from transgenic mice expressing mutant prion protein.

207

185

Polymerization of recombinant prion protein (recPrP), which was produced in bacteria, into amyloid fibers was accompanied by the acquisition of prion infectivity. We report here that partially purified preparations of prions seed the polymerization of recPrP into amyloid as detected by a fluorescence shift in the dye Thioflavin T. Our amyloid seeding assay (ASA) detected PrP Sc , the sole component of the prion, in brain samples from humans with sporadic Creutzfeldt–Jakob disease, as well as in rodents with experimental prion disease. The ASA detected a variety of prion strains passaged in both mice and hamsters. The sensitivity of the ASA varied with strain type; for hamster Sc237 prions, the limit of detection was ≈1 fg. Some prion strains consist largely of protease-sensitive PrP Sc (sPrP Sc ), and these strains were readily detected by ASA. Our studies show that the ASA provides an alternative methodology for detecting both sPrP Sc and protease-resistant PrP Sc that does not rely on protease digestion or immunodetection.

Section: Prion-infected Brain Homogenates Can Seed Amyloid Formationmentioning

confidence: 99%

Prion detection by an amyloid seeding assay

Colby

Zhang²,

Wang³

et al. 2007

207

185

“…De novo production of infectious prions from PRNP with point mutations would represent a useful tool for elucidating the origin of prion infectivity in genetic TSEs. Transgenic mice expressing Prnp with point mutations, insertions, or deletions develop a spectrum of neurological diseases with clinical or histological features reminiscent of TSEs (8)(9)(10)(11). However, de novo infectivity was claimed only for mice expressing Prnp P101L , which mimics the Gerstmann-Sträussler-Scheinkerassociated P102L point mutation of human PRNP.…”

mentioning

confidence: 99%

De novo generation of a transmissible spongiform encephalopathy by mouse transgenesis

Sigurdson¹,

Nilsson²,

Hornemann

et al. 2009

179

200

Most transmissible spongiform encephalopathies arise either spontaneously or by infection. Mutations of PRNP, which encodes the prion protein, PrP, segregate with phenotypically similar diseases. Here we report that moderate overexpression in transgenic mice of mPrP(170N,174T), a mouse PrP with two point mutations that subtly affect the structure of its globular domain, causes a fully penetrant lethal spongiform encephalopathy with cerebral PrP plaques. This genetic disease was reproduced with 100% attack rate by intracerebral inoculation of brain homogenate to tga20 mice overexpressing WT PrP, and from the latter to WT mice, but not to PrP-deficient mice. Upon successive transmissions, the incubation periods decreased and PrP became more protease-resistant, indicating the presence of a strain barrier that was gradually overcome by repeated passaging. This shows that expression of a subtly altered prion protein, with known 3D structure, efficiently generates a prion disease.amyloid ͉ neurodegeneration ͉ prion ͉ species barrier ͉ transgenic mice

“…The P102L mutation of GSS was introduced into the MoPrP transgene, and five lines of Tg-(MoPrP-P101L) mice expressing high levels of mutant PrP developed spontaneous CNS degeneration consisting of widespread vacuolation of the neuropil, astrocytic gliosis, and numerous PrP amyloid plaques similar to those seen in the brains of humans who die from GSS(P102L) (248)(249)(250). Brain extracts prepared from spontaneously ill Tg(MoPrP-P101L) mice transmitted CNS degeneration to Tg196 mice but contained no protease-resistant PrP (249,250). The Tg196 mice do not develop spontaneous disease but express low levels of the mutant transgene MoPrP-P101L and are deficient for mouse PrP (Prnp 0/0 ) (221).…”

mentioning

confidence: 99%

Molecular characterization of proteolytic cleavage sites of the Pseudomonas syringae effector AvrRpt2

Chisholm

Dahlbeck

Krishnamurthy

et al. 2005

137

138

Prions are unprecedented infectious pathogens that cause a group of invariably fatal neurodegenerative diseases by an entirely novel mechanism. Prion diseases may present as genetic, infectious, or sporadic disorders, all of which involve modification of the prion protein (PrP). Bovine spongiform encephalopathy (BSE), scrapie of sheep, and Creutzfeldt-Jakob disease (CJD) of humans are among the most notable prion diseases. Prions are transmissible particles that are devoid of nucleic acid and seem to be composed exclusively of a modified protein (PrP Sc ). The normal, cellular PrP (PrP C ) is converted into PrP Sc through a posttranslational process during which it acquires a high ␤-sheet content. The species of a particular prion is encoded by the sequence of the chromosomal PrP gene of the mammals in which it last replicated. In contrast to pathogens carrying a nucleic acid genome, prions appear to encipher strain-specific properties in the tertiary structure of PrP Sc . Transgenetic studies argue that PrP Sc acts as a template upon which PrP C is refolded into a nascent PrP Sc molecule through a process facilitated by another protein. Miniprions generated in transgenic mice expressing PrP, in which nearly half of the residues were deleted, exhibit unique biological properties and should facilitate structural studies of PrP Sc . While knowledge about prions has profound implications for studies of the structural plasticity of proteins, investigations of prion diseases suggest that new strategies for the prevention and treatment of these disorders may also find application in the more common degenerative diseases.