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Updated: May 1, 2026
Protein Misfolding Cyclic Amplification of Prions
Published on: November 7, 2012
Sensitive detection of pathological prion protein by cyclic amplification of protein misfolding
G P Saborio1, B Permanne, C Soto
1Serono Pharmaceutical Research Institute, Geneva, Switzerland. gabriela.saborio@serono.com
Abstract:
Prions are the infectious agents responsible for transmissible spongiform encephalopathies. The principal component of prions is the glycoprotein PrP(Sc), which is a conformationally modified isoform of a normal cell-surface protein called PrP(C) (ref. 1). During the time between infection and the appearance of the clinical symptoms, minute amounts of PrP(Sc) replicate by conversion of host PrP(C), generating large amounts of PrP(Sc) aggregates in the brains of diseased individuals. We aimed to reproduce this event in vitro. Here we report a procedure involving cyclic amplification of protein misfolding that allows a rapid conversion of large excess PrP(C) into a protease-resistant, PrP(Sc)-like form in the presence of minute quantities of PrP(Sc) template. In this procedure, conceptually analogous to polymerase chain reaction cycling, aggregates formed when PrP(Sc) is incubated with PrP(C) are disrupted by sonication to generate multiple smaller units for the continued formation of new PrP(Sc). After cyclic amplification more than 97% of the protease-resistant PrP present in the sample corresponds to newly converted protein. The method could be applied to diagnose the presence of currently undetectable prion infectious agent in tissues and biological fluids, and may provide a unique opportunity to determine whether PrP(Sc) replication results in the generation of infectivity in vitro.
Insights
Scientists developed a new in vitro method to rapidly replicate prion protein (PrPSc) aggregates. This cyclic amplification technique mimics polymerase chain reaction (PCR) and could aid in diagnosing prion diseases.
Area of Science:
- Neuroscience
- Biochemistry
- Molecular Biology
Background:
- Prions cause transmissible spongiform encephalopathies.
- Prions consist of misfolded PrPSc glycoprotein, converted from normal PrPC.
- PrPSc aggregates in the brain during disease progression.
Purpose of the Study:
- To replicate prion protein misfolding and aggregation in vitro.
- To develop a method for rapid conversion of PrPC to PrPSc-like forms.
Main Methods:
- Cyclic amplification of protein misfolding, analogous to PCR.
- Sonication to disrupt PrPSc aggregates, generating more conversion sites.
- Incubation of PrPSc template with excess PrPC.
Main Results:
- Achieved rapid conversion of PrPC to a protease-resistant, PrPSc-like form in vitro.
- Over 97% of protease-resistant PrP was newly converted protein after amplification.
- Demonstrated successful in vitro replication of prion protein misfolding.
Conclusions:
- The cyclic amplification method efficiently reproduces prion replication in vitro.
- This technique has potential applications in diagnosing prion infectious agents.
- It may offer a tool to study prion infectivity generation.
