scholarly journals The actin cytoskeletal network plays a role in yeast prion transmission and contributes to prion stability

2020 ◽  
Vol 114 (3) ◽  
pp. 480-494 ◽  
Author(s):  
Jane E. Dorweiler ◽  
Mitchell J. Oddo ◽  
Douglas R. Lyke ◽  
Jacob A. Reilly ◽  
Brett T. Wisniewski ◽  
...  
Keyword(s):  
Yeast Prion ◽  
Cytoskeletal Network ◽  
Prion Transmission

scholarly journals Soluble oligomers are sufficient for transmission of a yeast prion but do not confer phenotype

2013 ◽  
Vol 203 (2) ◽  
pp. 197-204 ◽  
Author(s):  
Jennifer E. Dulle ◽  
Rachel E. Bouttenot ◽  
Lisa A. Underwood ◽  
Heather L. True
Keyword(s):  
Prion Proteins ◽  
Valuable Insight ◽  
Amyloid Formation ◽  
Functional Requirements ◽  
Yeast Prion ◽  
Amyloidogenic Proteins ◽  
Isolation And Characterization ◽  
Prion Transmission ◽  
In Cells

Amyloidogenic proteins aggregate through a self-templating mechanism that likely involves oligomeric or prefibrillar intermediates. For disease-associated amyloidogenic proteins, such intermediates have been suggested to be the primary cause of cellular toxicity. However, isolation and characterization of these oligomeric intermediates has proven difficult, sparking controversy over their biological relevance in disease pathology. Here, we describe an oligomeric species of a yeast prion protein in cells that is sufficient for prion transmission and infectivity. These oligomers differ from the classic prion aggregates in that they are soluble and less resistant to SDS. We found that large, SDS-resistant aggregates were required for the prion phenotype but that soluble, more SDS-sensitive oligomers contained all the information necessary to transmit the prion conformation. Thus, we identified distinct functional requirements of two types of prion species for this endogenous epigenetic element. Furthermore, the nontoxic, self-replicating amyloid conformers of yeast prion proteins have again provided valuable insight into the mechanisms of amyloid formation and propagation in cells.

3-D examination of the cytoskeletal sheets of mammalian eggs

1992 ◽  
Vol 50 (1) ◽  
pp. 914-915
Author(s):  
Carolyn A. Larabell ◽  
David G. Capco ◽  
G. Ian Gallicano ◽  
Robert W. McGaughey ◽  
Karsten Dierksen ◽  
...  
Keyword(s):  
Actin Filaments ◽  
Somatic Cells ◽  
Freeze Fracture ◽  
Blastocyst Stage ◽  
Cell Cytoplasm ◽  
Planar Structures ◽  
Cytoskeletal Network ◽  
Entire Cell ◽  
Cytoskeletal Networks ◽  
Mammalian Eggs

Mammalian eggs and embryos contain an elaborate cytoskeletal network of “sheets” which are distributed throughout the entire cell cytoplasm. Cytoskeletal sheets are long, planar structures unlike the cytoskeletal networks typical of somatic cells (actin filaments, microtubules, and intermediate filaments), which are filamentous. These sheets are not found in mammalian somatic cells nor are they found in nonmammalian eggs or embryos. Evidence that they are, indeed, cytoskeletal in nature is derived from studies demonstrating that 1) the sheets are retained in the detergent-resistant cytoskeleton fraction; 2) there are no associated membranes (determined by freeze-fracture); and 3) the sheets dissociate into filaments at the blastocyst stage of embryogenesis. Embedment-free sections of hamster eggs viewed at 60 kV show sheets running across the egg cytoplasm (Fig. 1). Although this approach provides excellent global views of the sheets and their reorganization during development, the mechanism of image formation for embedment-free sections does not permit evaluation of the sheets at high resolution.

scholarly journals Humanized Transgenic Mice Are Resistant to Chronic Wasting Disease Prions From Norwegian Reindeer and Moose

2021 ◽  
Author(s):  
Jonathan D F Wadsworth ◽  
Susan Joiner ◽  
Jacqueline M Linehan ◽  
Kezia Jack ◽  
Huda Al-Doujaily ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Brain Tissue ◽  
Chronic Wasting Disease ◽  
Transmissible Spongiform Encephalopathy ◽  
Spongiform Encephalopathy ◽  
Zoonotic Potential ◽  
Wasting Disease ◽  
Human Prion Protein ◽  
Prion Transmission ◽  
Wild Reindeer

Abstract Chronic wasting disease (CWD) is the transmissible spongiform encephalopathy or prion disease affecting cervids. In 2016, the first cases of CWD were reported in Europe in Norwegian wild reindeer and moose. The origin and zoonotic potential of these new prion isolates remain unknown. In this study to investigate zoonotic potential we inoculated brain tissue from CWD-infected Norwegian reindeer and moose into transgenic mice overexpressing human prion protein. After prolonged postinoculation survival periods no evidence for prion transmission was seen, suggesting that the zoonotic potential of these isolates is low.

scholarly journals Compositional Determinants of Prion Formation in Yeast

2009 ◽  
Vol 30 (1) ◽  
pp. 319-332 ◽  
Author(s):  
James A. Toombs ◽  
Blake R. McCarty ◽  
Eric D. Ross
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Amyloid Formation ◽  
Yeast Prion ◽  
Hydrophobic Residues ◽  
Predictive Methods ◽  
Infectious Proteins ◽  
Β Sheet ◽  
Eukaryotic Genomes

ABSTRACT Numerous prions (infectious proteins) have been identified in yeast that result from the conversion of soluble proteins into β-sheet-rich amyloid-like protein aggregates. Yeast prion formation is driven primarily by amino acid composition. However, yeast prion domains are generally lacking in the bulky hydrophobic residues most strongly associated with amyloid formation and are instead enriched in glutamines and asparagines. Glutamine/asparagine-rich domains are thought to be involved in both disease-related and beneficial amyloid formation. These domains are overrepresented in eukaryotic genomes, but predictive methods have not yet been developed to efficiently distinguish between prion and nonprion glutamine/asparagine-rich domains. We have developed a novel in vivo assay to quantitatively assess how composition affects prion formation. Using our results, we have defined the compositional features that promote prion formation, allowing us to accurately distinguish between glutamine/asparagine-rich domains that can form prion-like aggregates and those that cannot. Additionally, our results explain why traditional amyloid prediction algorithms fail to accurately predict amyloid formation by the glutamine/asparagine-rich yeast prion domains.

scholarly journals Sorting of a nonmuscle tropomyosin to a novel cytoskeletal compartment in skeletal muscle results in muscular dystrophy

2004 ◽  
Vol 166 (5) ◽  
pp. 685-696 ◽  
Author(s):  
Anthony J. Kee ◽  
Galina Schevzov ◽  
Visalini Nair-Shalliker ◽  
C. Stephen Robinson ◽  
Bernadette Vrhovski ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscular Dystrophy ◽  
Actin Cytoskeleton ◽  
Cross Sections ◽  
Thin Filament ◽  
Distinct Structure ◽  
Adjacent Structure ◽  
Cytoskeletal Network ◽  
Ragged Red Fiber

Tropomyosin (Tm) is a key component of the actin cytoskeleton and >40 isoforms have been described in mammals. In addition to the isoforms in the sarcomere, we now report the existence of two nonsarcomeric (NS) isoforms in skeletal muscle. These isoforms are excluded from the thin filament of the sarcomere and are localized to a novel Z-line adjacent structure. Immunostained cross sections indicate that one Tm defines a Z-line adjacent structure common to all myofibers, whereas the second Tm defines a spatially distinct structure unique to muscles that undergo chronic or repetitive contractions. When a Tm (Tm3) that is normally absent from muscle was expressed in mice it became associated with the Z-line adjacent structure. These mice display a muscular dystrophy and ragged-red fiber phenotype, suggestive of disruption of the membrane-associated cytoskeletal network. Our findings raise the possibility that mutations in these tropomyosin and these structures may underpin these types of myopathies.

THE EVOLUTION OF THE EVOLVABILITY PROPERTIES OF THE YEAST PRION [PSI+]

Evolution ◽  
2003 ◽  
Vol 57 (7) ◽  
pp. 1498 ◽  
Author(s):  
Joanna Masel ◽  
Aviv Bergman
Keyword(s):  
Yeast Prion

scholarly journals The HAL3-PPZ1 dependent regulation of nonsense suppression efficiency in yeast and its influence on manifestation of the yeast prion-like determinant [ISP+]

2007 ◽  
Vol 12 (4) ◽  
pp. 435-445 ◽  
Author(s):  
Anna Aksenova ◽  
Iván Muñoz ◽  
Kirill Volkov ◽  
Joaquín Ariño ◽  
Ludmila Mironova
Keyword(s):  
Nonsense Suppression ◽  
Yeast Prion ◽  
Suppression Efficiency

scholarly journals Distinct Subregions of Swi1 Manifest Striking Differences in Prion Transmission and SWI/SNF Function

2010 ◽  
Vol 30 (19) ◽  
pp. 4644-4655 ◽  
Author(s):  
Zhiqiang Du ◽  
Emily T. Crow ◽  
Hyun Seok Kang ◽  
Liming Li
Keyword(s):  
Chromatin Remodeling ◽  
De Novo ◽  
Amino Acid Residues ◽  
Coding Region ◽  
Conformational Switch ◽  
Amyloid Fibers ◽  
Aggregation Pattern ◽  
Prion Transmission ◽  
Shed Light

ABSTRACT We have recently reported that the yeast chromatin-remodeling factor Swi1 can exist as a prion, [SWI +], demonstrating a link between prionogenesis and global transcriptional regulation. To shed light on how the Swi1 conformational switch influences Swi1 function and to define the sequence and structural requirements for [SWI +] formation and propagation, we functionally dissected the Swi1 molecule. We show here that the [SWI +] prion features are solely attributable to the first 327 amino acid residues (N), a region that is asparagine rich. N was aggregated in [SWI+ ] cells but diffuse in [swi− ] cells; chromosomal deletion of the N-coding region resulted in [SWI +] loss, and recombinant N peptide was able to form infectious amyloid fibers in vitro, enabling [SWI +] de novo formation through a simple transformation. Although the glutamine-rich middle region (Q) was not sufficient to aggregate in [SWI +] cells or essential for SWI/SNF function, it significantly modified the Swi1 aggregation pattern and Swi1 function. We also show that excessive Swi1 incurred Li+/Na+ sensitivity and that the N/Q regions are important for this gain of sensitivity. Taken together, our results provide the final proof of “protein-only” transmission of [SWI +] and demonstrate that the widely distributed “dispensable” glutamine/asparagine-rich regions/motifs might have important and divergent biological functions.

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