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Efficient in vitro amplification of a mouse-adapted scrapie prion protein
Yuichi Murayama1, Miyako Yoshioka, Takashi Yokoyama
1Prion Disease Research Center, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan. ymura@affrc.go.jp
Abstract:
Protein misfolding cyclic amplification (PMCA) is a highly sensitive technique used to detect minute amounts of scrapie prion protein (PrP(Sc)), a major protein component of the infectious agents associated with prion diseases. Although exponential in vitro amplification of hamster scrapie PrP(Sc) has been established, the PMCA used was unsuccessful in achieving good amplification of PrP(Sc) from other animals. Here, we have investigated the cause of the insufficient PrP(Sc) amplification in mice and have developed an improved method suitable for amplification of the PrP(Sc) of the mouse-adapted scrapie prion strain Chandler. Mouse PrP(C), the cellular form of the prion protein, tends to become resistant to proteases during incubation independent of sonication. By adding digitonin to the reaction buffer as a lipid detergent, accumulation of the protease-resistant PrP(C) was inhibited; hence, mouse PrP(Sc) could be amplified to infinite levels. The present study is the first report describing effective amplification of PrP(Sc) of the mouse-adapted scrapie prion and this improved PMCA technique will contribute to prion research that uses mice as experimental animals.
Insights
Researchers improved protein misfolding cyclic amplification (PMCA) to detect mouse scrapie prion protein (PrPSc). Adding digitonin prevents protease resistance, enabling effective amplification for prion disease research in mice.
Area of Science:
- Neuroscience
- Biochemistry
- Molecular Biology
Background:
- Protein misfolding cyclic amplification (PMCA) detects scrapie prion protein (PrPSc).
- Existing PMCA methods struggle to amplify PrPSc from species other than hamsters, particularly mice.
- Mouse PrP(C) can develop protease resistance during incubation, hindering amplification.
Purpose of the Study:
- Investigate the reasons for insufficient PrPSc amplification in mice.
- Develop an improved PMCA method for amplifying mouse-adapted scrapie PrPSc.
- Enhance prion disease research using mouse models.
Main Methods:
- Investigated PrPSc amplification challenges in mice.
- Developed a modified PMCA protocol.
- Incorporated digitonin, a lipid detergent, into the reaction buffer.
- Assessed the inhibition of protease-resistant PrPC accumulation.
Main Results:
- Identified protease resistance of mouse PrPC as a key obstacle.
- Demonstrated effective amplification of mouse-adapted scrapie PrPSc using the improved method.
- Showed that digitonin prevents PrPC protease resistance during incubation.
Conclusions:
- The study presents the first successful amplification of mouse-adapted scrapie PrPSc.
- The enhanced PMCA technique overcomes previous limitations in mouse PrPSc detection.
- This improved method will significantly aid prion disease research involving mouse models.
