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Updated: Jul 17, 2025

High-throughput Screening for Protein-based Inheritance in S. cerevisiae
Published on: August 8, 2017
Prions in Microbes: The Least in the Most
Moonil Son1,2,3, Sia Han4, Seyeon Lee4
1Department of Microbiology, Pusan National University, Busan, 46241, Republic of Korea. moonilson@pusan.ac.kr.
Abstract:
Prions are infectious proteins that mostly replicate in self-propagating amyloid conformations (filamentous protein polymers) and consist of structurally altered normal soluble proteins. Prions can arise spontaneously in the cell without any clear reason and are generally considered fatal disease-causing agents that are only present in mammals. However, after the seminal discovery of two prions, [PSI+] and [URE3], in the eukaryotic model microorganism Saccharomyces cerevisiae, at least ten more prions have been discovered, and their biological and pathological effects on the host, molecular structure, and the relationship between prions and cellular components have been studied. In a filamentous fungus model, Podospora anserina, a vegetative incomparability-related [Het-s] prion that directly triggers cell death during anastomosis (hyphal fusion) was discovered. These prions in eukaryotic microbes have extended our understanding to overcome most fatal human prion/amyloid diseases. A prokaryotic microorganism (Clostridium botulinum) was reported to have a prion analog. The transcriptional regulators of C. botulinum-Rho can be converted into the self-replicating prion form ([RHO-X-C+]), which may affect global transcription. Here, we outline the major issues with prions in microbes and the lessons learned from the relatively uncovered microbial prion world.
Insights
Microbial prions, unlike those in mammals, offer insights into prion diseases. Studying these infectious proteins in organisms like yeast and fungi expands our understanding of their biology and potential therapeutic strategies.
Area of Science:
- Microbiology
- Molecular Biology
- Protein Science
Background:
- Prions are infectious proteins, typically amyloid conformations, causing fatal diseases primarily in mammals.
- The discovery of prions in model organisms like Saccharomyces cerevisiae ([PSI+], [URE3]) and Podospora anserina ([Het-s]) broadened prion research.
- Prion analogs have also been identified in prokaryotes, such as Clostridium botulinum.
Purpose of the Study:
- To outline key challenges and findings in the study of microbial prions.
- To explore the biological and pathological roles of prions in diverse microorganisms.
- To leverage insights from microbial prions for understanding and potentially treating human prion/amyloid diseases.
Main Methods:
- Review of existing literature on microbial prions.
- Analysis of prion discovery in eukaryotic microorganisms (yeast, fungi) and prokaryotes.
- Examination of prion structure, replication, and cellular interactions.
Main Results:
- Over ten prions have been identified in eukaryotic microbes beyond initial discoveries.
- [Het-s] prion in Podospora anserina directly induces cell death during hyphal fusion.
- A prion analog ([RHO-X-C+]) in Clostridium botulinum affects global transcription.
Conclusions:
- Microbial prions provide valuable models for studying prion biology and disease mechanisms.
- Research into microbial prions offers potential avenues for developing strategies against human prion and amyloid diseases.
- The uncovered microbial prion world holds significant lessons for protein misfolding disorders.
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