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The Mutability of Yeast Prions. Viruses 2022; 14:v14112337. [PMID: 36366434 PMCID: PMC9696419 DOI: 10.3390/v14112337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/10/2022] [Accepted: 10/23/2022] [Indexed: 02/01/2023] Open
Abstract
Prions replicate by a self-templating mechanism. Infidelity in the process can lead to the emergence of new infectious structures, referred to as variants or strains. The question of whether prions are prone to mis-templating is not completely answered. Our previous experiments with 23 variants of the yeast [PSI+] prion do not support broad mutability. However, it became clear recently that the heat shock protein Hsp104 can restrict [PSI+] strain variation. This raises the possibility that many transmutable variants of the prion may have been mistaken as faithful-propagating simply because the mutant structure was too sturdy or too frail to take root in the wild-type cell. Here, I alter the strength of Hsp104 in yeast, overexpressing wild-type Hsp104 or expressing the hypo-active Hsp104T160M mutant, and check if the new environments enable the variants to mutate. Two variants hitherto thought of as faithful-propagating are discovered to generate different structures, which are stabilized with the hypo-active chaperone. In contrast, most transmutable variants discovered in cells overexpressing Hsp104 have been correctly identified as such previously in wild-type cells without the overexpression. The majority of transmutable variants only mis-template the structure of VH, VK, or VL, which are the most frequently observed variants and do not spontaneously mutate. There are four additional variants that never give rise to different structures in all cell conditions tested. Therefore, quite a few [PSI+] variants are faithful-propagating, and even the transmutable ones do not freely evolve but can only change to limited structural types.
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2
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Holec SAM, Liu SL, Woerman AL. Consequences of variability in α-synuclein fibril structure on strain biology. Acta Neuropathol 2022; 143:311-330. [PMID: 35122113 DOI: 10.1007/s00401-022-02403-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 12/15/2022]
Abstract
Synucleinopathies are a group of clinically and neuropathologically distinct protein misfolding diseases caused by unique α-synuclein conformations, or strains. While multiple atomic resolution cryo-electron microscopy structures of α-synuclein fibrils are now deposited in Protein Data Bank, significant gaps in the biological consequences arising from each conformation have yet to be unraveled. Mutations in the α-synuclein gene (SNCA), cofactors, and the solvation environment contribute to the formation and maintenance of each disease-causing strain. This review highlights the impact of each of these factors on α-synuclein misfolding and discusses the implications of the resulting structural variability on therapeutic development.
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Affiliation(s)
- Sara A M Holec
- Department of Biology, Institute for Applied Life Sciences, University of Massachusetts Amherst, Amherst, MA, USA
| | - Samantha L Liu
- Department of Biology, Institute for Applied Life Sciences, University of Massachusetts Amherst, Amherst, MA, USA
- Molecular and Cellular Biology Program, Dartmouth College, Hanover, NH, USA
| | - Amanda L Woerman
- Department of Biology, Institute for Applied Life Sciences, University of Massachusetts Amherst, Amherst, MA, USA.
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3
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Block AJ, Shikiya RA, Eckland TE, Kincaid AE, Walters RW, Ma J, Bartz JC. Efficient interspecies transmission of synthetic prions. PLoS Pathog 2021; 17:e1009765. [PMID: 34260664 PMCID: PMC8312972 DOI: 10.1371/journal.ppat.1009765] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/26/2021] [Accepted: 06/29/2021] [Indexed: 11/18/2022] Open
Abstract
Prions are comprised solely of PrPSc, the misfolded self-propagating conformation of the cellular protein, PrPC. Synthetic prions are generated in vitro from minimal components and cause bona fide prion disease in animals. It is unknown, however, if synthetic prions can cross the species barrier following interspecies transmission. To investigate this, we inoculated Syrian hamsters with murine synthetic prions. We found that all the animals inoculated with murine synthetic prions developed prion disease characterized by a striking uniformity of clinical onset and signs of disease. Serial intraspecies transmission resulted in a rapid adaptation to hamsters. During the adaptation process, PrPSc electrophoretic migration, glycoform ratios, conformational stability and biological activity as measured by protein misfolding cyclic amplification remained constant. Interestingly, the strain that emerged shares a strikingly similar transmission history, incubation period, clinical course of disease, pathology and biochemical and biological features of PrPSc with 139H, a hamster adapted form of the murine strain 139A. Combined, these data suggest that murine synthetic prions are comprised of bona fide PrPSc with 139A-like strain properties that efficiently crosses the species barrier and rapidly adapts to hamsters resulting in the emergence of a single strain. The efficiency and specificity of interspecies transmission of murine synthetic prions to hamsters, with relevance to brain derived prions, could be a useful model for identification of structure function relationships between PrPSc and PrPC from different species. Prions have zoonotic potential as illustrated by the interspecies transmission of bovine spongiform encephalopathy to humans resulting in the emergence of a novel human prion disease. It is unknown if other prion diseases of animals, such as chronic wasting disease, can be transmitted to other species. Models to predict prion zoonotic potential do not exist, in part, due to the lack of understanding of how the structure of PrPSc from one species can convert PrPC from another species. Towards this end, we determined that murine synthetic prions, made from minimal components, can efficiently establish infection in hamsters whose transmission history, clinical features, pathology and biochemical properties of PrPSc are consistent with the reisolation of a known prion strain. We conclude that murine synthetic prions can recapitulate interspecies transmission and adaptation allowing for a more detailed mechanistic analysis in a simplified, trackable system.
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Affiliation(s)
- Alyssa J. Block
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Ronald A. Shikiya
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Thomas E. Eckland
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
| | - Anthony E. Kincaid
- Department of Pharmacy Science, Creighton University, Omaha, Nebraska, United States of America
| | - Ryan W. Walters
- Department of Medicine, Creighton University, Omaha, Nebraska, United States of America
| | - Jiyan Ma
- Van Andel Institute, Center for Neurodegenerative Science, Grand Rapids, Michigan, United States of America
| | - Jason C. Bartz
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, Nebraska, United States of America
- * E-mail:
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4
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Holec SA, Block AJ, Bartz JC. The role of prion strain diversity in the development of successful therapeutic treatments. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 175:77-119. [PMID: 32958242 PMCID: PMC8939712 DOI: 10.1016/bs.pmbts.2020.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Prions are a self-propagating misfolded conformation of a cellular protein. Prions are found in several eukaryotic organisms with mammalian prion diseases encompassing a wide range of disorders. The first recognized prion disease, the transmissible spongiform encephalopathies (TSEs), affect several species including humans. Alzheimer's disease, synucleinopathies, and tauopathies share a similar mechanism of self-propagation of the prion form of the disease-specific protein reminiscent of the infection process of TSEs. Strain diversity in prion disease is characterized by differences in the phenotype of disease that is hypothesized to be encoded by strain-specific conformations of the prion form of the disease-specific protein. Prion therapeutics that target the prion form of the disease-specific protein can lead to the emergence of drug-resistant strains of prions, consistent with the hypothesis that prion strains exist as a dynamic mixture of a dominant strain in combination with minor substrains. To overcome this obstacle, therapies that reduce or eliminate the template of conversion are efficacious, may reverse neuropathology, and do not result in the emergence of drug resistance. Recent advancements in preclinical diagnosis of prion infection may allow for a combinational approach that treats the prion form and the precursor protein to effectively treat prion diseases.
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Affiliation(s)
- Sara A.M. Holec
- Institute for Applied Life Sciences and Department of Biology, University of Massachusetts Amherst, Amherst, MA, United States,Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE, United States
| | - Alyssa J. Block
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE, United States
| | - Jason C. Bartz
- Department of Medical Microbiology and Immunology, School of Medicine, Creighton University, Omaha, NE, United States,Corresponding author:
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5
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Nonno R, Notari S, Di Bari MA, Cali I, Pirisinu L, d'Agostino C, Cracco L, Kofskey D, Vanni I, Lavrich J, Parchi P, Agrimi U, Gambetti P. Variable Protease-Sensitive Prionopathy Transmission to Bank Voles. Emerg Infect Dis 2019; 25:73-81. [PMID: 30561322 PMCID: PMC6302590 DOI: 10.3201/eid2501.180807] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Variably protease-sensitive prionopathy (VPSPr), a recently described human sporadic prion disease, features a protease-resistant, disease-related prion protein (resPrPD) displaying 5 fragments reminiscent of Gerstmann-Sträussler-Scheinker disease. Experimental VPSPr transmission to human PrP-expressing transgenic mice, although replication of the VPSPr resPrPD profile succeeded, has been incomplete because of second passage failure. We bioassayed VPSPr in bank voles, which are susceptible to human prion strains. Transmission was complete; first-passage attack rates were 5%-35%, and second-passage rates reached 100% and survival times were 50% shorter. We observed 3 distinct phenotypes and resPrPD profiles; 2 imitated sporadic Creutzfeldt-Jakob disease resPrPD, and 1 resembled Gerstmann-Sträussler-Scheinker disease resPrPD. The first 2 phenotypes may be related to the presence of minor PrPD components in VPSPr. Full VPSPr transmission confirms permissiveness of bank voles to human prions and suggests that bank vole PrP may efficiently reveal an underrepresented native strain but does not replicate the complex VPSPr PrPD profile.
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Torrent J, Martin D, Igel-Egalon A, Béringue V, Rezaei H. High-Pressure Response of Amyloid Folds. Viruses 2019; 11:v11030202. [PMID: 30823361 PMCID: PMC6466028 DOI: 10.3390/v11030202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 02/21/2019] [Accepted: 02/22/2019] [Indexed: 12/22/2022] Open
Abstract
The abnormal protein aggregates in progressive neurodegenerative disorders, such as Alzheimer’s, Parkinson’s and prion diseases, adopt a generic structural form called amyloid fibrils. The precise amyloid fold can differ between patients and these differences are related to distinct neuropathological phenotypes of the diseases. A key focus in current research is the molecular mechanism governing such structural diversity, known as amyloid polymorphism. In this review, we focus on our recent work on recombinant prion protein (recPrP) and the use of pressure as a variable for perturbing protein structure. We suggest that the amyloid polymorphism is based on volumetric features. Accordingly, pressure is the thermodynamic parameter that fits best to exploit volume differences within the states of a chemical reaction, since it shifts the equilibrium constant to the state that has the smaller volume. In this context, there are analogies with the process of correct protein folding, the high pressure-induced effects of which have been studied for more than a century and which provides a valuable source of inspiration. We present a short overview of this background and review our recent results regarding the folding, misfolding, and aggregation-disaggregation of recPrP under pressure. We present preliminary experiments aimed at identifying how prion protein fibril diversity is related to the quaternary structure by using pressure and varying protein sequences. Finally, we consider outstanding questions and testable mechanistic hypotheses regarding the multiplicity of states in the amyloid fold.
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Affiliation(s)
- Joan Torrent
- MMDN, Univ. Montpellier, EPHE, INSERM, U1198, F-34095 Montpellier, France.
| | - Davy Martin
- Institut National de la Recherche Agronomique, UR892, Virologie Immunologie Moléculaires, F-78350 Jouy-en-Josas, France.
| | - Angélique Igel-Egalon
- Institut National de la Recherche Agronomique, UR892, Virologie Immunologie Moléculaires, F-78350 Jouy-en-Josas, France.
| | - Vincent Béringue
- Institut National de la Recherche Agronomique, UR892, Virologie Immunologie Moléculaires, F-78350 Jouy-en-Josas, France.
| | - Human Rezaei
- Institut National de la Recherche Agronomique, UR892, Virologie Immunologie Moléculaires, F-78350 Jouy-en-Josas, France.
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7
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Soto C, Pritzkow S. Protein misfolding, aggregation, and conformational strains in neurodegenerative diseases. Nat Neurosci 2018; 21:1332-1340. [PMID: 30250260 DOI: 10.1038/s41593-018-0235-9] [Citation(s) in RCA: 631] [Impact Index Per Article: 105.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 08/22/2018] [Indexed: 12/12/2022]
Abstract
A hallmark event in neurodegenerative diseases (NDs) is the misfolding, aggregation, and accumulation of proteins, leading to cellular dysfunction, loss of synaptic connections, and brain damage. Despite the involvement of distinct proteins in different NDs, the process of protein misfolding and aggregation is remarkably similar. A recent breakthrough in the field was the discovery that misfolded protein aggregates can self-propagate through seeding and spread the pathological abnormalities between cells and tissues in a manner akin to the behavior of infectious prions in prion diseases. This discovery has vast implications for understanding the mechanisms involved in the initiation and progression of NDs, as well as for the design of novel strategies for treatment and diagnosis. In this Review, we provide a critical discussion of the role of protein misfolding and aggregation in NDs. Commonalities and differences between distinct protein aggregates will be highlighted, in addition to evidence supporting the hypothesis that misfolded aggregates can be transmissible by the prion principle. We will also describe the molecular basis and implications for prion-like conformational strains, cross-interaction between different misfolded proteins in the brain, and how these concepts can be applied to the development of novel strategies for therapy and diagnosis.
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Affiliation(s)
- Claudio Soto
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas McGovern Medical School, Houston, Texas, USA.
| | - Sandra Pritzkow
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas McGovern Medical School, Houston, Texas, USA
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8
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Abstract
Prion diseases are a group of fatal neurodegenerative disorders caused by the misfolding of the cellular prion protein (PrPC) into a pathogenic conformation (PrPSc). PrPSc is capable of folding into multiple self-replicating prion strains that produce phenotypically distinct neurological disorders. Evidence suggests that the structural heterogeneity of PrPSc is the molecular basis of strain-specific prion properties. The self-templating of PrPSc typically ensures that prion strains breed true upon passage. However, prion strains also have the capacity to conformationally transform to maximize their rate of replication in a given environment. Here, we provide an overview of the prion-strain phenomenon and describe the role of strain adaptation in drug resistance. We also describe recent evidence that shows the presence of distinct conformational strains in other neurodegenerative disorders.
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Affiliation(s)
- Sina Ghaemmaghami
- Department of Biology, University of Rochester, Rochester, New York 14627
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9
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Moda F. Protein Misfolding Cyclic Amplification of Infectious Prions. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 150:361-374. [PMID: 28838669 DOI: 10.1016/bs.pmbts.2017.06.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Transmissible spongiform encephalopathies, or prion diseases, are a group of incurable disorders caused by the accumulation of an abnormally folded prion protein (PrPSc) in the brain. According to the "protein-only" hypothesis, PrPSc is the infectious agent able to propagate the disease by acting as a template for the conversion of the correctly folded prion protein (PrPC) into the pathological isoform. Recently, the mechanism of PrPC conversion has been mimicked in vitro using an innovative technique named protein misfolding cyclic amplification (PMCA). This technology represents a great tool for studying diverse aspects of prion biology in the field of basic research and diagnosis. Moreover, PMCA can be expanded for the study of the misfolding process associated to other neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and frontotemporal lobar degeneration.
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Affiliation(s)
- Fabio Moda
- IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy.
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10
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Cracco L, Notari S, Cali I, Sy MS, Chen SG, Cohen ML, Ghetti B, Appleby BS, Zou WQ, Caughey B, Safar JG, Gambetti P. Novel strain properties distinguishing sporadic prion diseases sharing prion protein genotype and prion type. Sci Rep 2017; 7:38280. [PMID: 28091514 PMCID: PMC5238384 DOI: 10.1038/srep38280] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 11/04/2016] [Indexed: 11/23/2022] Open
Abstract
In most human sporadic prion diseases the phenotype is consistently associated with specific pairings of the genotype at codon 129 of the prion protein gene and conformational properties of the scrapie PrP (PrPSc) grossly identified types 1 and 2. This association suggests that the 129 genotype favours the selection of a distinct strain that in turn determines the phenotype. However, this mechanism cannot play a role in the phenotype determination of sporadic fatal insomnia (sFI) and a subtype of sporadic Creutzfeldt-Jakob disease (sCJD) identified as sCJDMM2, which share 129 MM genotype and PrPSc type 2 but are associated with quite distinct phenotypes. Our detailed comparative study of the PrPSc conformers has revealed major differences between the two diseases, which preferentially involve the PrPSc component that is sensitive to digestion with proteases (senPrPSc) and to a lesser extent the resistant component (resPrPSc). We conclude that these variations are consistent with two distinct strains in sFI and sCJDMM2, and that the rarer sFI is the result of a variant strain selection pathway that might be favoured by a different brain site of initial PrPSc formation in the two diseases.
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Affiliation(s)
- Laura Cracco
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Silvio Notari
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Ignazio Cali
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Man-Sun Sy
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Shu G Chen
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Mark L Cohen
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America.,National Prion Disease Pathology Surveillance Center, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Bernardino Ghetti
- Department of Pathology and Laboratory Medicine, Division of Neuropathology, Indiana University, Indianapolis, Indiana, United States of America
| | - Brian S Appleby
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America.,National Prion Disease Pathology Surveillance Center, Case Western Reserve University, Cleveland, Ohio, United States of America.,Department of Neurology, Case Western Reserve University, Cleveland, Ohio, United States of America.,Department of Psychiatry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Wen-Quan Zou
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America.,National Prion Disease Pathology Surveillance Center, Case Western Reserve University, Cleveland, Ohio, United States of America.,Department of Neurology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Byron Caughey
- Laboratory of Persistent Viral Diseases, NIH/NIAID Rocky Mountain Laboratories, Hamilton, Montana, United States of America
| | - Jiri G Safar
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America.,National Prion Disease Pathology Surveillance Center, Case Western Reserve University, Cleveland, Ohio, United States of America.,Department of Neurology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Pierluigi Gambetti
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
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11
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Vanni I, Migliore S, Cosseddu GM, Di Bari MA, Pirisinu L, D’Agostino C, Riccardi G, Agrimi U, Nonno R. Isolation of a Defective Prion Mutant from Natural Scrapie. PLoS Pathog 2016; 12:e1006016. [PMID: 27880822 PMCID: PMC5120856 DOI: 10.1371/journal.ppat.1006016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 10/21/2016] [Indexed: 11/18/2022] Open
Abstract
It is widely known that prion strains can mutate in response to modification of the replication environment and we have recently reported that prion mutations can occur in vitro during amplification of vole-adapted prions by Protein Misfolding Cyclic Amplification on bank vole substrate (bvPMCA). Here we exploited the high efficiency of prion replication by bvPMCA to study the in vitro propagation of natural scrapie isolates. Although in vitro vole-adapted PrPSc conformers were usually similar to the sheep counterpart, we repeatedly isolated a PrPSc mutant exclusively when starting from extremely diluted seeds of a single sheep isolate. The mutant and faithful PrPSc conformers showed to be efficiently autocatalytic in vitro and were characterized by different PrP protease resistant cores, spanning aa ∼155–231 and ∼80–231 respectively, and by different conformational stabilities. The two conformers could thus be seen as different bona fide PrPSc types, putatively accounting for prion populations with different biological properties. Indeed, once inoculated in bank vole the faithful conformer was competent for in vivo replication while the mutant was unable to infect voles, de facto behaving like a defective prion mutant. Overall, our findings confirm that prions can adapt and evolve in the new replication environments and that the starting population size can affect their evolutionary landscape, at least in vitro. Furthermore, we report the first example of “authentic” defective prion mutant, composed of brain-derived PrPC and originating from a natural scrapie isolate. Our results clearly indicate that the defective mutant lacks of some structural characteristics, that presumably involve the central region ∼90–155, critical for infectivity but not for in vitro replication. Finally, we propose a molecular mechanism able to account for the discordant in vitro and in vivo behavior, suggesting possible new paths for investigating the molecular bases of prion infectivity. Prions are unique infectious agents, consisting of PrPSc, a self-propagating aggregated conformer of the host-encoded prion protein PrPC. Despite the absence of any nucleic acid information, prions exist as distinct strains that share the same amino acid sequence but differ in their conformation. Moreover, prions can mutate and are thus heterogeneous populations able to evolve and adapt to new replication environments. During in vitro amplification of sheep scrapie, we found that a prion mutant could be obtained from one natural isolate. The prion mutant identified was characterized in vivo and in vitro, showing unusual biochemical and biological features: a smaller than usual C-terminal proteinase resistant core of PrPSc, which spans aa ∼155–231, and the inability to propagate in vivo despite an efficient autocatalytic replication in vitro. With such a signature, we denoted the mutant as a “defective” prion mutant. We thus postulate a new hypothesis for the discrepancy between the in vitro and in vivo behavior of the defective mutant and suggest that the central PrPSc domain ∼90–160 might have a key role in prion replication. This work provides important new insights into the mechanism underpinning prion replication and has numerous implications for understanding the molecular requirements indispensable for prion infectivity.
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Affiliation(s)
- Ilaria Vanni
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Sergio Migliore
- Istituto Zooprofilattico Sperimentale of Sicily "A. Mirri", Palermo, Italy
| | - Gian Mario Cosseddu
- Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Teramo, Italy
| | - Michele Angelo Di Bari
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Laura Pirisinu
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Claudia D’Agostino
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Geraldina Riccardi
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Umberto Agrimi
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
| | - Romolo Nonno
- Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Rome, Italy
- * E-mail:
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12
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Chapuis J, Moudjou M, Reine F, Herzog L, Jaumain E, Chapuis C, Quadrio I, Boulliat J, Perret-Liaudet A, Dron M, Laude H, Rezaei H, Béringue V. Emergence of two prion subtypes in ovine PrP transgenic mice infected with human MM2-cortical Creutzfeldt-Jakob disease prions. Acta Neuropathol Commun 2016; 4:10. [PMID: 26847207 PMCID: PMC4743415 DOI: 10.1186/s40478-016-0284-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 01/26/2016] [Indexed: 11/23/2022] Open
Abstract
Introduction Mammalian prions are proteinaceous pathogens responsible for a broad range of fatal neurodegenerative diseases in humans and animals. These diseases can occur spontaneously, such as Creutzfeldt-Jakob disease (CJD) in humans, or be acquired or inherited. Prions are primarily formed of macromolecular assemblies of the disease-associated prion protein PrPSc, a misfolded isoform of the host-encoded prion protein PrPC. Within defined host-species, prions can exist as conformational variants or strains. Based on both the M/V polymorphism at codon 129 of PrP and the electrophoretic signature of PrPSc in the brain, sporadic CJD is classified in different subtypes, which may encode different strains. A transmission barrier, the mechanism of which remains unknown, limits prion cross-species propagation. To adapt to the new host, prions have the capacity to ‘mutate’ conformationally, leading to the emergence of a variant with new biological properties. Here, we transmitted experimentally one rare subtype of human CJD, designated cortical MM2 (129 MM with type 2 PrPSc), to transgenic mice overexpressing either human or the VRQ allele of ovine PrPC. Results In marked contrast with the reported absence of transmission to knock-in mice expressing physiological levels of human PrP, this subtype transmitted faithfully to mice overexpressing human PrP, and exhibited unique strain features. Onto the ovine PrP sequence, the cortical MM2 subtype abruptly evolved on second passage, thereby allowing emergence of a pair of strain variants with distinct PrPSc biochemical characteristics and differing tropism for the central and lymphoid tissues. These two strain components exhibited remarkably distinct replicative properties in cell-free amplification assay, allowing the ‘physical’ cloning of the minor, lymphotropic component, and subsequent isolation in ovine PrP mice and RK13 cells. Conclusions Here, we provide in-depth assessment of the transmissibility and evolution of one rare subtype of sporadic CJD upon homologous and heterologous transmission. The notion that the environment or matrix where replication is occurring is key to the selection and preferential amplification of prion substrain components raises new questions on the determinants of prion replication within and between species. These data also further interrogate on the interplay between animal and human prions. Electronic supplementary material The online version of this article (doi:10.1186/s40478-016-0284-9) contains supplementary material, which is available to authorized users.
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13
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Torrent J, Lange R, Igel-Egalon A, Béringue V, Rezaei H. Getting to the core of prion superstructural variability. Prion 2015; 10:1-8. [PMID: 26636374 PMCID: PMC4981190 DOI: 10.1080/19336896.2015.1122161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The phenomenon of protein superstructural polymorphism has become the subject of increased research activity. Besides the relevance to explain the existence of multiple prion strains, such activity is partly driven by the recent finding that in many age-related neurodegenerative diseases highly ordered self-associated forms of peptides and proteins might be the structural basis of prion-like processes and strains giving rise to different disease phenotypes. Biophysical studies of prion strains have been hindered by a lack of tools to characterize inherently noncrystalline, heterogeneous and insoluble proteins. A description of the pressure response of prion quaternary structures might change this picture. This is because applying pressure induces quaternary structural changes of PrP, such as misfolding and self-assembly. From the thermodynamics of these processes, structural features in terms of associated volume changes can then be deduced. We suggest that conformation-enciphered prion strains can be distinguished in terms of voids in the interfaces of the constituting PrP protomers and thus in their volumetric properties.
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Affiliation(s)
- Joan Torrent
- a Institut National de la Recherche Agronomique, UR892, Virologie Immunologie Moléculaires , Jouy-en-Josas , France
| | - Reinhard Lange
- b Institut National de la Recherche Agronomique, UMR1208, Ingénierie des Agropolymères et Technologies Emergentes, Université Montpellier , Montpellier , France
| | - Angelique Igel-Egalon
- a Institut National de la Recherche Agronomique, UR892, Virologie Immunologie Moléculaires , Jouy-en-Josas , France
| | - Vincent Béringue
- a Institut National de la Recherche Agronomique, UR892, Virologie Immunologie Moléculaires , Jouy-en-Josas , France
| | - Human Rezaei
- a Institut National de la Recherche Agronomique, UR892, Virologie Immunologie Moléculaires , Jouy-en-Josas , France
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Shikiya RA, Eckland TE, Young AJ, Bartz JC. Prion formation, but not clearance, is supported by protein misfolding cyclic amplification. Prion 2015; 8:415-20. [PMID: 25482601 DOI: 10.4161/19336896.2014.983759] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Prion diseases are fatal transmissible neurodegenerative disorders that affect animals including humans. The kinetics of prion infectivity and PrP(Sc) accumulation can differ between prion strains and within a single strain in different tissues. The net accumulation of PrP(Sc) in animals is controlled by the relationship between the rate of PrP(Sc) formation and clearance. Protein misfolding cyclic amplification (PMCA) is a powerful technique that faithfully recapitulates PrP(Sc) formation and prion infectivity in a cell-free system. PMCA has been used as a surrogate for animal bioassay and can model species barriers, host range, strain co-factors and strain interference. In this study we investigated if degradation of PrP(Sc) and/or prion infectivity occurs during PMCA. To accomplish this we performed PMCA under conditions that do not support PrP(Sc) formation and did not observe either a reduction in PrP(Sc) abundance or an extension of prion incubation period, compared to untreated control samples. These results indicate that prion clearance does not occur during PMCA. These data have significant implications for the interpretation of PMCA based experiments such as prion amplification rate, adaptation to new species and strain interference where production and clearance of prions can affect the outcome.
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Affiliation(s)
- Ronald A Shikiya
- a Department of Medical Microbiology and Immunology ; School of Medicine; Creighton University ; Omaha, NE USA
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15
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Abstract
The unusual genetic properties of the non-chromosomal genetic elements [URE3] and [PSI+] led to them being identified as prions (infectious proteins) of Ure2p and Sup35p respectively. Ure2p and Sup35p, and now several other proteins, can form amyloid, a linear ordered polymer of protein monomers, with a part of each molecule, the prion domain, forming the core of this β-sheet structure. Amyloid filaments passed to a new cell seed the conversion of the normal form of the protein into the same amyloid form. The cell's phenotype is affected, usually from the deficiency of the normal form of the protein. Solid-state NMR studies indicate that the yeast prion amyloids are in-register parallel β-sheet structures, in which each residue (e.g. Asn35) forms a row along the filament long axis. The favourable interactions possible for aligned identical hydrophilic and hydrophobic residues are believed to be the mechanism for propagation of amyloid conformation. Thus, just as DNA mediates inheritance by templating its own sequence, these proteins act as genes by templating their conformation. Distinct isolates of a given prion have different biological properties, presumably determined by differences between the amyloid structures. Many lines of evidence indicate that the Saccharomyces cerevisiae prions are pathological disease agents, although the example of the [Het-s] prion of Podospora anserina shows that a prion can have beneficial aspects.
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16
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Oelschlegel AM, Geissen M, Lenk M, Riebe R, Angermann M, Schaetzl H, Groschup MH. A bovine cell line that can be infected by natural sheep scrapie prions. PLoS One 2015; 10:e0117154. [PMID: 25565633 PMCID: PMC4286239 DOI: 10.1371/journal.pone.0117154] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 12/19/2014] [Indexed: 11/18/2022] Open
Abstract
Cell culture systems represent a crucial part in basic prion research; yet, cell lines that are susceptible to prions, especially to field isolated prions that were not adapted to rodents, are very rare. The purpose of this study was to identify and characterize a cell line that was susceptible to ruminant-derived prions and to establish a stable prion infection within it. Based on species and tissue of origin as well as PrP expression rate, we pre-selected a total of 33 cell lines that were then challenged with natural and with mouse propagated BSE or scrapie inocula. Here, we report the successful infection of a non-transgenic bovine cell line, a sub-line of the bovine kidney cell line MDBK, with natural sheep scrapie prions. This cell line retained the scrapie infection for more than 200 passages. Selective cloning resulted in cell populations with increased accumulation of PrPres, although this treatment was not mandatory for retaining the infection. The infection remained stable, even under suboptimal culture conditions. The resulting infectivity of the cells was confirmed by mouse bioassay (Tgbov mice, Tgshp mice). We believe that PES cells used together with other prion permissive cell lines will prove a valuable tool for ongoing efforts to understand and defeat prions and prion diseases.
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Affiliation(s)
- Anja M. Oelschlegel
- Institute of Novel and Emerging Infectious Diseases at the Friedrich-Loeffler-Institut, Greifswald—Isle of Riems, Germany
- Project Group Neuropharmacology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Markus Geissen
- Institute of Novel and Emerging Infectious Diseases at the Friedrich-Loeffler-Institut, Greifswald—Isle of Riems, Germany
- Department of Vascular Medicine, University Heart Centre Hamburg, UKE, Hamburg, Germany
| | - Matthias Lenk
- Department of Experimental Animal Facilities and Biorisk Management at the Friedrich-Loeffler-Institut, Greifswald—Isle of Riems, Germany
| | - Roland Riebe
- Department of Experimental Animal Facilities and Biorisk Management at the Friedrich-Loeffler-Institut, Greifswald—Isle of Riems, Germany
| | - Marlies Angermann
- Institute of Novel and Emerging Infectious Diseases at the Friedrich-Loeffler-Institut, Greifswald—Isle of Riems, Germany
- Administrative District Office Goerlitz, Goerlitz, Germany
| | - Hermann Schaetzl
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, Canada
| | - Martin H. Groschup
- Institute of Novel and Emerging Infectious Diseases at the Friedrich-Loeffler-Institut, Greifswald—Isle of Riems, Germany
- * E-mail:
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17
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Holmes BB, Diamond MI. Prion-like properties of Tau protein: the importance of extracellular Tau as a therapeutic target. J Biol Chem 2014; 289:19855-61. [PMID: 24860099 DOI: 10.1074/jbc.r114.549295] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Work over the past 4 years indicates that multiple proteins associated with neurodegenerative diseases, especially Tau and α-synuclein, can propagate aggregates between cells in a prion-like manner. This means that once an aggregate is formed it can escape the cell of origin, contact a connected cell, enter the cell, and induce further aggregation via templated conformational change. The prion model predicts a key role for extracellular protein aggregates in mediating progression of disease. This suggests new therapeutic approaches based on blocking neuronal uptake of protein aggregates and promoting their clearance. This will likely include therapeutic antibodies or small molecules, both of which can be developed and optimized in vitro prior to preclinical studies.
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Affiliation(s)
- Brandon B Holmes
- From the Department of Neurology, Washington University in St. Louis, St. Louis, Missouri 63110
| | - Marc I Diamond
- From the Department of Neurology, Washington University in St. Louis, St. Louis, Missouri 63110
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18
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Abstract
In several recent studies transmissible prion disease was induced in animals by inoculation with recombinant prion protein amyloid fibrils produced in vitro. Serial transmission of amyloid fibrils gave rise to a new class of prion strains of synthetic origin. Gradual transformation of disease phenotypes and PrP(Sc) properties was observed during serial transmission of synthetic prions, a process that resembled the phenomenon of prion strain adaptation. The current article discusses the remarkable parallels between phenomena of prion strain adaptation that accompanies cross-species transmission and the evolution of synthetic prions occurring within the same host. Two alternative mechanisms underlying prion strain adaptation and synthetic strain evolution are discussed. The current article highlights the complexity of the prion transmission barrier and strain adaptation and proposes that the phenomenon of prion adaptation is more common than previously thought.
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Affiliation(s)
- Ilia V Baskakov
- Center for Biomedical Engineering and Technology; Department of Anatomy and Neurobiology; University of Maryland School of Medicine; Baltimore, MD USA
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Affiliation(s)
- Natallia Makarava
- Center for Biomedical Engineering and Technology and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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20
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Bateman DA, Wickner RB. The [PSI+] prion exists as a dynamic cloud of variants. PLoS Genet 2013; 9:e1003257. [PMID: 23382698 PMCID: PMC3561065 DOI: 10.1371/journal.pgen.1003257] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 12/04/2012] [Indexed: 12/29/2022] Open
Abstract
[PSI+] is an amyloid-based prion of Sup35p, a subunit of the translation termination factor. Prion “strains” or “variants” are amyloids with different conformations of a single protein sequence, conferring different phenotypes, but each relatively faithfully propagated. Wild Saccharomyces cerevisiae isolates have SUP35 alleles that fall into three groups, called reference, Δ19, and E9, with limited transmissibility of [PSI+] between cells expressing these different polymorphs. Here we show that prion transmission pattern between different Sup35 polymorphs is prion variant-dependent. Passage of one prion variant from one Sup35 polymorph to another need not change the prion variant. Surprisingly, simple mitotic growth of a [PSI+] strain results in a spectrum of variant transmission properties among the progeny clones. Even cells that have grown for >150 generations continue to vary in transmission properties, suggesting that simple variant segregation is insufficient to explain the results. Rather, there appears to be continuous generation of a cloud of prion variants, with one or another becoming stochastically dominant, only to be succeeded by a different mixture. We find that among the rare wild isolates containing [PSI+], all indistinguishably “weak” [PSI+], are several different variants based on their transmission efficiencies to other Sup35 alleles. Most show some limitation of transmission, indicating that the evolved wild Sup35 alleles are effective in limiting the spread of [PSI+]. Notably, a “strong [PSI+]” can have any of several different transmission efficiency patterns, showing that “strong” versus “weak” is insufficient to indicate prion variant uniformity. The [PSI+] prion (infectious protein) of yeast is a self-propagating amyloid (filamentous protein polymer) of the Sup35 protein, a subunit of the translation termination factor. A single protein can form many biologically distinct prions, called prion variants. Wild yeast strains have three groups of Sup35 sequences (polymorphs), which partially block transmission of the [PSI+] prion from cell to cell. We find that [PSI+] variants (including the rare [PSI+] from wild yeasts) show different transmission patterns from one Sup35 sequence to another. Moreover, we find segregation of different prion variants on mitotic growth and evidence for generation of new variants with growth under non-selective conditions. This data supports the “prion cloud” model, that prions are not uniform structures but have an array of related self-propagating amyloid structures.
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Affiliation(s)
- David A. Bateman
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Reed B. Wickner
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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21
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Makarava N, Savtchenko R, Baskakov IV. Selective amplification of classical and atypical prions using modified protein misfolding cyclic amplification. J Biol Chem 2012; 288:33-41. [PMID: 23168413 DOI: 10.1074/jbc.m112.419531] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
With the development of protein misfolding cyclic amplification (PMCA), the topic of faithful propagation of prion strain-specific structures has been constantly debated. Here we show that by subjecting brain material of a synthetic strain consisting of a mixture of self-replicating states to PMCAb, selective amplification of PrP(Sc) could be achieved, and that PMCAb mimicked the evolutionary trend observed during serial transmission in animals. On the other hand, using modified PMCAb conditions that employ partially deglycosylated PrP(C) (dgPMCAb), an alternative transmissible state referred to as atypical protease-resistant form of the prion protein (atypical PrPres) was selectively amplified from a mixture. Surprisingly, when hamster-adapted strains (263K and Hyper) were subjected to dgPMCAb, their proteinase K digestion profile underwent a dramatic transformation, suggesting that a mixture of atypical PrPres and PrP(Sc) might be present in brain-derived materials. However, detailed analysis revealed that the proteinase K-resistant profile of PrP(Sc) changed in response to dgPMCAb. Despite these changes, the 263K strain-specific disease phenotype was preserved after passage through dgPMCAb. This study revealed that the change in PrP(Sc) biochemical phenotype does not always represent an irreversible transformation of a strain, but rather demonstrated the existence of a wide range of variation for strain-specific physical features in response to a change in prion replication environment. The current work introduced a new PMCA technique for amplification of atypical PrPres and raised a number of questions about the need for a clever distinction between actual strain mutation and variation of strain-specific features in response to a change in the replication environment.
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Affiliation(s)
- Natallia Makarava
- Center for Biomedical Engineering and Technology and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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22
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Abstract
Evolution of RNA viruses occurs through disequilibria of collections of closely related mutant spectra or mutant clouds termed viral quasispecies. Here we review the origin of the quasispecies concept and some biological implications of quasispecies dynamics. Two main aspects are addressed: (i) mutant clouds as reservoirs of phenotypic variants for virus adaptability and (ii) the internal interactions that are established within mutant spectra that render a virus ensemble the unit of selection. The understanding of viruses as quasispecies has led to new antiviral designs, such as lethal mutagenesis, whose aim is to drive viruses toward low fitness values with limited chances of fitness recovery. The impact of quasispecies for three salient human pathogens, human immunodeficiency virus and the hepatitis B and C viruses, is reviewed, with emphasis on antiviral treatment strategies. Finally, extensions of quasispecies to nonviral systems are briefly mentioned to emphasize the broad applicability of quasispecies theory.
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Affiliation(s)
- Esteban Domingo
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), C/ Nicolás Cabrera, Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain.
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23
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The extended cell panel assay characterizes the relationship of prion strains RML, 79A, and 139A and reveals conversion of 139A to 79A-like prions in cell culture. J Virol 2012; 86:5297-303. [PMID: 22379091 DOI: 10.1128/jvi.00181-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Three commonly used isolates of murine prions, 79A, 139A, and RML, were derived from the so-called Chandler isolate, which was obtained by propagating prions from scrapie-infected goat brain in mice. RML is widely believed to be identical with 139A; however, using the extended cell panel assay (ECPA), we here show that 139A and RML isolates are distinct, while 79A and RML could not be distinguished. We undertook to clone 79A and 139A prions by endpoint dilution in murine neuroblastoma-derived PK1 cells. Cloned 79A prions, when returned to mouse brain, were unchanged and indistinguishable from RML by ECPA. However, 139A-derived clones, when returned to brain, yielded prions distinct from 139A and similar to 79A and RML. Thus, when 139A prions were transferred to PK1 cells, 79A/RML-like prions, either present as a minor component in the brain 139A population or generated by mutation in the cells, were selected and, after being returned to brain, were the major if not only component of the population.
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24
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King OD, Gitler AD, Shorter J. The tip of the iceberg: RNA-binding proteins with prion-like domains in neurodegenerative disease. Brain Res 2012; 1462:61-80. [PMID: 22445064 DOI: 10.1016/j.brainres.2012.01.016] [Citation(s) in RCA: 496] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 01/06/2012] [Accepted: 01/07/2012] [Indexed: 02/08/2023]
Abstract
Prions are self-templating protein conformers that are naturally transmitted between individuals and promote phenotypic change. In yeast, prion-encoded phenotypes can be beneficial, neutral or deleterious depending upon genetic background and environmental conditions. A distinctive and portable 'prion domain' enriched in asparagine, glutamine, tyrosine and glycine residues unifies the majority of yeast prion proteins. Deletion of this domain precludes prionogenesis and appending this domain to reporter proteins can confer prionogenicity. An algorithm designed to detect prion domains has successfully identified 19 domains that can confer prion behavior. Scouring the human genome with this algorithm enriches a select group of RNA-binding proteins harboring a canonical RNA recognition motif (RRM) and a putative prion domain. Indeed, of 210 human RRM-bearing proteins, 29 have a putative prion domain, and 12 of these are in the top 60 prion candidates in the entire genome. Startlingly, these RNA-binding prion candidates are inexorably emerging, one by one, in the pathology and genetics of devastating neurodegenerative disorders, including: amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U), Alzheimer's disease and Huntington's disease. For example, FUS and TDP-43, which rank 1st and 10th among RRM-bearing prion candidates, form cytoplasmic inclusions in the degenerating motor neurons of ALS patients and mutations in TDP-43 and FUS cause familial ALS. Recently, perturbed RNA-binding proteostasis of TAF15, which is the 2nd ranked RRM-bearing prion candidate, has been connected with ALS and FTLD-U. We strongly suspect that we have now merely reached the tip of the iceberg. We predict that additional RNA-binding prion candidates identified by our algorithm will soon surface as genetic modifiers or causes of diverse neurodegenerative conditions. Indeed, simple prion-like transfer mechanisms involving the prion domains of RNA-binding proteins could underlie the classical non-cell-autonomous emanation of neurodegenerative pathology from originating epicenters to neighboring portions of the nervous system. This article is part of a Special Issue entitled RNA-Binding Proteins.
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Affiliation(s)
- Oliver D King
- Boston Biomedical Research Institute, 64 Grove St., Watertown, MA 02472, USA.
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25
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Weissmann C, Li J, Mahal SP, Browning S. Prions on the move. EMBO Rep 2011; 12:1109-17. [PMID: 21997298 PMCID: PMC3207107 DOI: 10.1038/embor.2011.192] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 08/30/2011] [Indexed: 02/07/2023] Open
Abstract
Prions consist mainly, if not entirely, of PrP(Sc), an aggregated conformer of the host protein PrP(C). Prions come in different strains, all based on the same PrP(C) sequence, but differing in their conformations. The efficiency of prion transmission between species is usually low, but increases after serial transmission in the new host, suggesting a process involving mutation and selection. Even within the same species, the transfer of prions between cell types entails a selection of favoured 'substrains', and propagation of prions in the presence of an inhibitory drug can result in the appearance of drug-resistant prion populations. We propose that prion populations are comprised of a variety of conformers, constituting 'quasi-species', from which the one replicating most efficiently in a particular environment is selected.
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Affiliation(s)
- Charles Weissmann
- Department of Infectology, Scripps Florida, 130 Scripps Way, Jupiter, Florida 33458, USA.
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