The yeast Sup35 protein is a translation termination factor with the unusual capacity to form a self-perpetuating ordered aggregate (the prion [PSI+]), resulting in heritable changes in the fidelity of translation termination. In different genetic backgrounds [PSI+] produces distinct sets of phenotypes, altering growth and survival in diverse conditions. Several questions remain to be addressed to understand the full biological implications of this prion element. 1) What is the molecular nature of the phenotypic diversity revealed by the [PSI+] prion? Analyses of the [PSI+]-dependent traits suggest that they result from both nonsense suppression and protein aggregation. 2) Recent data suggests that several [PSI+] - dependent phenotypes are complex traits. These traits require a combination of many factors and provide a viable model to investigate the phenotypic effects of environmental conditions coupled with both genetic and epigenetic factors. In one such trait, a prion dependent alteration in morphology, a contributing pathway has been identified, and the interplay of nonsense suppression, protein aggregation, and the environment that produces the phenotype will be investigated. 3) How is this epigenetic element regulated? What are the biological consequences of this prion? Addressing these questions will allow for a greater understanding of the impact of [PSI+] on population biology, survival, and evolution of yeast. This research will dissect the mechanistic nature of the [PSI+] element and determine if this prion provides a unique mechanism for phenotypic plasticity that might promote the evolution of complex traits. Moreover, this work may provide additional insights into the wealth of prion biology and the physiological impact of this type of epigenetic regulation. Furthermore, this yeast prion provides a model system to understand the environmental cues that trigger protein aggregation, which has broad implications in understanding the initiation of protein misfolding associated with several neurodegenerative disorders. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
1R01GM072778-01A1
Application #
6966519
Study Section
Genetic Variation and Evolution Study Section (GVE)
Program Officer
Anderson, James J
Project Start
2005-08-01
Project End
2010-07-31
Budget Start
2005-08-01
Budget End
2006-07-31
Support Year
1
Fiscal Year
2005
Total Cost
$284,294
Indirect Cost
Name
Washington University
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Keefer, Kathryn M; Stein, Kevin C; True, Heather L (2017) Heterologous prion-forming proteins interact to cross-seed aggregation in Saccharomyces cerevisiae. Sci Rep 7:5853
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Keefer, Kathryn M; True, Heather L (2017) A toxic imbalance of Hsp70s in Saccharomyces cerevisiae is caused by competition for cofactors. Mol Microbiol 105:860-868
Keefer, Kathryn M; True, Heather L (2016) Prion-Associated Toxicity is Rescued by Elimination of Cotranslational Chaperones. PLoS Genet 12:e1006431
Dulle, Jennifer E; Stein, Kevin C; True, Heather L (2014) Regulation of the Hsp104 middle domain activity is critical for yeast prion propagation. PLoS One 9:e87521
Westergard, Laura; True, Heather L (2014) Extracellular environment modulates the formation and propagation of particular amyloid structures. Mol Microbiol 92:698-715
Stein, Kevin C; Bengoechea, Rocio; Harms, Matthew B et al. (2014) Myopathy-causing mutations in an HSP40 chaperone disrupt processing of specific client conformers. J Biol Chem 289:21120-30
Stein, Kevin C; True, Heather L (2014) Structural variants of yeast prions show conformer-specific requirements for chaperone activity. Mol Microbiol 93:1156-71
Westergard, Laura; True, Heather L (2014) Wild yeast harbour a variety of distinct amyloid structures with strong prion-inducing capabilities. Mol Microbiol 92:183-93
Stein, Kevin C; True, Heather L (2014) Prion strains and amyloid polymorphism influence phenotypic variation. PLoS Pathog 10:e1004328

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