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Partial copurification of scrapie-associated fibrils and scrapie infectivity
Abstract:
The association between scrapie infectivity and scrapie-associated fibrils (SAF) during a partial purification procedure for infectivity was investigated. Scrapie infectivity and SAF can be separated from most membrane components by subcellular fractionation of infected mouse brain to obtain a synaptosomal fraction, followed by detergent treatment and density gradient centrifugation. After different detergent treatments, with either octyl glucoside or sodium N-lauroyl sarcosinate, SAF showed differing sedimentation characteristics but nevertheless cosedimented with scrapie infectivity in both cases. Copurification under two different conditions provides more evidence that SAF may be a form of the infectious agent of scrapie.
Insights
Researchers investigated the link between scrapie infectivity and scrapie-associated fibrils (SAF). Results show SAF copurified with infectivity, suggesting SAF may be the infectious agent.
Area of Science:
- Neuroscience
- Biochemistry
- Infectious Diseases
Background:
- Scrapie is a fatal neurodegenerative disease caused by prions.
- Scrapie-associated fibrils (SAF) are protein aggregates found in the brains of infected animals.
- The exact nature of the infectious agent of scrapie remains under investigation.
Purpose of the Study:
- To investigate the association between scrapie infectivity and scrapie-associated fibrils (SAF).
- To determine if SAF are a component of the scrapie infectious agent.
Main Methods:
- Subcellular fractionation of infected mouse brain to obtain synaptosomal fractions.
- Detergent treatment using octyl glucoside or sodium N-lauroyl sarcosinate.
- Density gradient centrifugation to analyze sedimentation characteristics.
Main Results:
- Scrapie infectivity and SAF were separated from most membrane components.
- SAF exhibited different sedimentation patterns based on detergent treatment.
- Crucially, SAF consistently cosedimented with scrapie infectivity under both tested conditions.
Conclusions:
- The copurification of SAF with scrapie infectivity provides strong evidence for their association.
- These findings support the hypothesis that scrapie-associated fibrils (SAF) may represent the infectious agent of scrapie.
- Further research is warranted to fully elucidate the role of SAF in prion diseases.