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Investigating the Spreading and Toxicity of Prion-like Proteins Using the Metazoan Model Organism C. elegans
Published on: January 8, 2015
Prion switching in response to environmental stress
Jens Tyedmers1, Maria Lucia Madariaga, Susan Lindquist
1Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, USA.
Plos Biology
|December 11, 2008
Summary
Yeast prion [PSI(+)] acts as an evolvability capacitor, increasing adaptive variation under stress. This mechanism enhances survival in fluctuating environments by exposing hidden genetic variation when needed most.
Area of Science:
- Evolutionary biology
- Genetics
- Molecular biology
Background:
- Evolution relies on translating genetic variation into heritable phenotypic variation.
- Evolvability mechanisms that generate adaptive variation could accelerate evolution.
- Capacitor systems may accumulate cryptic genetic variation, releasing it under stress.
Purpose of the Study:
- To investigate if the yeast prion [PSI(+)] functions as a mechanism for evolvability.
- To determine if [PSI(+)] induction frequency increases under stressful conditions.
- To identify factors influencing [PSI(+)] induction and its role in adaptation.
Main Methods:
- Conducted a high-throughput, genome-wide screen for factors affecting [PSI(+)] induction.
- Exposed yeast cells to various stress conditions, including oxidative stress and high salt.
- Quantified the frequency of [PSI(+)] induction in response to different stress levels.
Main Results:
- The yeast prion [PSI(+)] exposes a significant amount of previously hidden genetic variation.
- Phenotypes generated by [PSI(+)] are advantageous approximately 25% of the time.
- Prion induction increased up to 60-fold under stress, correlating with stress severity.
Conclusions:
- [PSI(+)] acts as a capacitor, increasing the rate of adaptive evolution.
- Stress response genes and signal transducers are key regulators of [PSI(+)] induction.
- The [PSI(+)] system enhances survival in fluctuating environments, promoting evolvability.
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