1
|
Matiiv AB, Trubitsina NP, Matveenko AG, Barbitoff YA, Zhouravleva GA, Bondarev SA. Structure and Polymorphism of Amyloid and Amyloid-Like Aggregates. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:450-463. [PMID: 35790379 DOI: 10.1134/s0006297922050066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 04/08/2022] [Accepted: 04/09/2022] [Indexed: 06/15/2023]
Abstract
Amyloids are protein aggregates with the cross-β structure. The interest in amyloids is explained, on the one hand, by their role in the development of socially significant human neurodegenerative diseases, and on the other hand, by the discovery of functional amyloids, whose formation is an integral part of cellular processes. To date, more than a hundred proteins with the amyloid or amyloid-like properties have been identified. Studying the structure of amyloid aggregates has revealed a wide variety of protein conformations. In the review, we discuss the diversity of protein folds in the amyloid-like aggregates and the characteristic features of amyloid aggregates that determine their unusual properties, including stability and interaction with amyloid-specific dyes. The review also describes the diversity of amyloid aggregates and its significance for living organisms.
Collapse
Affiliation(s)
- Anton B Matiiv
- Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, 199034, Russia
| | - Nina P Trubitsina
- Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, 199034, Russia
| | - Andrew G Matveenko
- Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, 199034, Russia
| | - Yury A Barbitoff
- Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, 199034, Russia
- Bioinformatics Institute, Saint Petersburg, 197342, Russia
| | - Galina A Zhouravleva
- Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, 199034, Russia
- Laboratory of Amyloid Biology, Saint Petersburg State University, Saint Petersburg, 199034, Russia
| | - Stanislav A Bondarev
- Department of Genetics and Biotechnology, Saint Petersburg State University, Saint Petersburg, 199034, Russia.
- Laboratory of Amyloid Biology, Saint Petersburg State University, Saint Petersburg, 199034, Russia
| |
Collapse
|
2
|
Villali J, Dark J, Brechtel TM, Pei F, Sindi SS, Serio TR. Nucleation seed size determines amyloid clearance and establishes a barrier to prion appearance in yeast. Nat Struct Mol Biol 2020; 27:540-549. [PMID: 32367069 PMCID: PMC7293557 DOI: 10.1038/s41594-020-0416-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 03/18/2020] [Indexed: 12/14/2022]
Abstract
Amyloid appearance is a rare event that is promoted in the presence of
other aggregated proteins. These aggregates were thought to act by templating
the formation of an assembly-competent nucleation seed, but we find an
unanticipated role for them in enhancing the persistence of amyloid after it
arises. Specifically, Saccharoymyces cerevisiae Rnq1 amyloid
reduces chaperone-mediated disassembly of Sup35 amyloid, promoting its
persistence in yeast. Mathematical modeling and corresponding in
vivo experiments link amyloid persistence to the conformationally
defined size of the Sup35 nucleation seed and suggest that amyloid is actively
cleared by disassembly below this threshold to suppress appearance of the
[PSI+] prion in vivo.
Remarkably, this framework resolves multiple known inconsistencies in the
appearance and curing of yeast prions. Thus, our observations establish the size
of the nucleation seed as a previously unappreciated characteristic of prion
variants that is key to understanding transitions between prion states.
Collapse
Affiliation(s)
- Janice Villali
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA.,Relay Therapeutics, Cambridge, MA, USA
| | - Jason Dark
- Department of Applied Mathematics, University of California, Merced, Merced, CA, USA
| | - Teal M Brechtel
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA
| | - Fen Pei
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA.,BioLegend, San Diego, CA, USA
| | - Suzanne S Sindi
- Department of Applied Mathematics, University of California, Merced, Merced, CA, USA.
| | - Tricia R Serio
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, MA, USA.
| |
Collapse
|
3
|
Riemschoss K, Arndt V, Bolognesi B, von Eisenhart-Rothe P, Liu S, Buravlova O, Duernberger Y, Paulsen L, Hornberger A, Hossinger A, Lorenzo-Gotor N, Hogl S, Müller SA, Tartaglia G, Lichtenthaler SF, Vorberg IM. Fibril-induced glutamine-/asparagine-rich prions recruit stress granule proteins in mammalian cells. Life Sci Alliance 2019; 2:2/4/e201800280. [PMID: 31266883 PMCID: PMC6607448 DOI: 10.26508/lsa.201800280] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 06/22/2019] [Accepted: 06/25/2019] [Indexed: 12/11/2022] Open
Abstract
This study provides evidence that exogenous proteinaceous seeds can induce protein aggregates that sequester stress granule components independent of stress granule assembly. Prions of lower eukaryotes are self-templating protein aggregates that replicate by converting homotypic proteins into stable, tightly packed beta-sheet–rich protein assemblies. Propagation is mediated by prion domains, low-complexity regions enriched in polar and devoid of charged amino acid residues. In mammals, compositionally similar domains modulate the assembly of dynamic stress granules (SGs) that associate via multivalent weak interactions. Dysregulation of SGs composed of proteins with prion-like domains has been proposed to underlie the formation of pathological inclusions in several neurodegenerative diseases. The events that drive prion-like domains into transient or solid assemblies are not well understood. We studied the interactors of the prototype prion domain NM of Saccharomyces cerevisiae Sup35 in its soluble or fibril-induced prion conformation in the mammalian cytosol. We show that the interactomes of soluble and prionized NM overlap with that of SGs. Prion induction by exogenous seeds does not cause SG assembly, demonstrating that colocalization of aberrant protein inclusions with SG components does not necessarily reveal SGs as initial sites of protein misfolding.
Collapse
Affiliation(s)
- Katrin Riemschoss
- German Center for Neurodegenerative Diseases Bonn (DZNE e.V.), Bonn, Germany
| | - Verena Arndt
- German Center for Neurodegenerative Diseases Bonn (DZNE e.V.), Bonn, Germany
| | - Benedetta Bolognesi
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation, Barcelona, Spain
| | | | - Shu Liu
- German Center for Neurodegenerative Diseases Bonn (DZNE e.V.), Bonn, Germany
| | | | - Yvonne Duernberger
- German Center for Neurodegenerative Diseases Bonn (DZNE e.V.), Bonn, Germany
| | - Lydia Paulsen
- German Center for Neurodegenerative Diseases Bonn (DZNE e.V.), Bonn, Germany
| | - Annika Hornberger
- German Center for Neurodegenerative Diseases Bonn (DZNE e.V.), Bonn, Germany
| | - André Hossinger
- German Center for Neurodegenerative Diseases Bonn (DZNE e.V.), Bonn, Germany
| | - Nieves Lorenzo-Gotor
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation, Barcelona, Spain
| | - Sebastian Hogl
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Stephan A Müller
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Neuroproteomics, School of Medicine, Klinikum rechts der Isar, and Institute for Advanced Study, Technical University of Munich, Munich, Germany
| | - Gian Tartaglia
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | - Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Neuroproteomics, School of Medicine, Klinikum rechts der Isar, and Institute for Advanced Study, Technical University of Munich, Munich, Germany
| | - Ina M Vorberg
- German Center for Neurodegenerative Diseases Bonn (DZNE e.V.), Bonn, Germany .,Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| |
Collapse
|
4
|
Serio TR. [PIN+]ing down the mechanism of prion appearance. FEMS Yeast Res 2019; 18:4923032. [PMID: 29718197 PMCID: PMC5889010 DOI: 10.1093/femsyr/foy026] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 03/03/2018] [Indexed: 11/13/2022] Open
Abstract
Prions are conformationally flexible proteins capable of adopting a native state and a spectrum of alternative states associated with a change in the function of the protein. These alternative states are prone to assemble into amyloid aggregates, which provide a structure for self-replication and transmission of the underlying conformer and thereby the emergence of a new phenotype. Amyloid appearance is a rare event in vivo, regulated by both the aggregation propensity of prion proteins and their cellular environment. How these forces normally intersect to suppress amyloid appearance and the ways in which these restrictions can be bypassed to create protein-only phenotypes remain poorly understood. The most widely studied and perhaps most experimentally tractable system to explore the mechanisms regulating amyloid appearance is the [PIN+] prion of Saccharomyces cerevisiae. [PIN+] is required for the appearance of the amyloid state for both native yeast proteins and for human proteins expressed in yeast. These observations suggest that [PIN+] facilitates the bypass of amyloid regulatory mechanisms by other proteins in vivo. Several models of prion appearance are compatible with current observations, highlighting the complexity of the process and the questions that must be resolved to gain greater insight into the mechanisms regulating these events.
Collapse
Affiliation(s)
- Tricia R Serio
- The University of Massachusetts-Amherst, Department of Biochemistry and Molecular Biology, 240 Thatcher Rd, N360, Amherst, MA 01003, USA
| |
Collapse
|
5
|
Yu CI, King CY. Forms and abundance of chaperone proteins influence yeast prion variant competition. Mol Microbiol 2019; 111:798-810. [PMID: 30582872 DOI: 10.1111/mmi.14192] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2018] [Indexed: 02/01/2023]
Abstract
[PSI+ ] variants are different infectious conformations of the same Sup35 protein. We show that when [PSI+ ] variants VK and VL co-infect a dividing host, only one prevails in the end and the host genetic background is involved in winner selection. In the 5V-H19 background, the VK variant dominates over the VL variant. The order of dominance is reversed in the 74-D694 background, where VL can coexists with VK for a short period, but will eventually take over. Differential interaction of chaperone proteins with distinct prion variant conformations can influence the outcome of competition. Expanding the Glycine/Methionine-rich domain of Sis1, an Hsp40 protein, helps the propagation of VL. Over-expression of the Hsp70 protein Ssa2 lowers the number of prion particles (propagons) in the cell. There is more reduction for VK than VL, causing the latter to dominate in some of the 5V-H19 and all of the 74-D694 cells tested. Consistently, depleting Ssa1 in 74-D694 strengthens VK. Swapping chromosomal alleles of SSA1/2 and SIS1 between 5V-H19 and 74-D694, including cognate promoters, is not sufficient to change the native dominance order of each background, suggesting there exist additional polymorphic factors that modulate [PSI+ ] competition.
Collapse
Affiliation(s)
- Chang-I Yu
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Chih-Yen King
- Institute of Molecular Biology, Academia Sinica, Taipei, 11529, Taiwan
| |
Collapse
|
6
|
Tikhodeyev ON, Tarasov OV, Bondarev SA. Allelic variants of hereditary prions: The bimodularity principle. Prion 2017; 11:4-24. [PMID: 28281926 PMCID: PMC5360123 DOI: 10.1080/19336896.2017.1283463] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 01/04/2017] [Accepted: 01/10/2017] [Indexed: 12/26/2022] Open
Abstract
Modern biology requires modern genetic concepts equally valid for all discovered mechanisms of inheritance, either "canonical" (mediated by DNA sequences) or epigenetic. Applying basic genetic terms such as "gene" and "allele" to protein hereditary factors is one of the necessary steps toward these concepts. The basic idea that different variants of the same prion protein can be considered as alleles has been previously proposed by Chernoff and Tuite. In this paper, the notion of prion allele is further developed. We propose the idea that any prion allele is a bimodular hereditary system that depends on a certain DNA sequence (DNA determinant) and a certain epigenetic mark (epigenetic determinant). Alteration of any of these 2 determinants may lead to establishment of a new prion allele. The bimodularity principle is valid not only for hereditary prions; it seems to be universal for any epigenetic hereditary factor.
Collapse
Affiliation(s)
- Oleg N. Tikhodeyev
- Department of Genetics & Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Oleg V. Tarasov
- Department of Genetics & Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia
- Saint-Petersburg Scientific Center of RAS, Saint-Petersburg, Russia
| | - Stanislav A. Bondarev
- Department of Genetics & Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia
- The Laboratory of Amyloid Biology, Saint-Petersburg State University, Saint-Petersburg, Russia
| |
Collapse
|
7
|
Huang YW, Chang YC, Diaz-Avalos R, King CY. W8, a new Sup35 prion strain, transmits distinctive information with a conserved assembly scheme. Prion 2016; 9:207-27. [PMID: 26038983 DOI: 10.1080/19336896.2015.1039217] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Prion strains are different self-propagating conformers of the same infectious protein. Three strains of the [PSI] prion, infectious forms of the yeast Sup35 protein, have been previously characterized in our laboratory. Here we report the discovery of a new [PSI] strain, named W8. We demonstrate its robust cellular propagation as well as the protein-only transmission. To reveal strain-specific sequence requirement, mutations that interfered with the propagation of W8 were identified by consecutive substitution of residues 5-55 of Sup35 by proline and insertion of glycine at alternate sites in this segment. Interestingly, propagating W8 with single mutations at residues 5-7 and around residue 43 caused the strain to transmute. In contrast to the assertion that [PSI] existed as a dynamic cloud of sub-structures, no random drift in transmission characteristics was detected in mitotically propagated W8 populations. Electron diffraction and mass-per-length measurements indicate that, similar to the 3 previously characterized strains, W8 fibers are composed of about 1 prion molecule per 4.7-Å cross-β repeat period. Thus differently folded single Sup35 molecules, not dimeric and trimeric assemblies, form the basic repeating units to build the 4 [PSI] strains.
Collapse
Key Words
- 5-FOA, 5-fluoroorotic acid
- Aβ, amyloid β-protein
- GFP, green fluorescent protein
- PrP, prion protein
- SC, synthetic complete
- STEM, scanning transmission electron microscopy
- YPD, yeast extract, peptone, dextrose
- amyloid, prion strain, [PSI+], SUP35, yeast
- mpl, mass per length
Collapse
Affiliation(s)
- Yu-Wen Huang
- a Molecular and Cell Biology; Taiwan International Graduate Program; Academia Sinica and National Defense Medical Center ; Taipei , Taiwan
| | | | | | | |
Collapse
|
8
|
Wong SH, King CY. Amino Acid Proximities in Two Sup35 Prion Strains Revealed by Chemical Cross-linking. J Biol Chem 2015; 290:25062-71. [PMID: 26265470 DOI: 10.1074/jbc.m115.676379] [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] [Received: 07/02/2015] [Indexed: 12/26/2022] Open
Abstract
Strains of the yeast prion [PSI] are different folding patterns of the same Sup35 protein, which stacks up periodically to form a prion fiber. Chemical cross-linking is employed here to probe different fiber structures assembled with a mutant Sup35 fragment. The photo-reactive cross-linker, p-benzoyl-l-phenylalanine (pBpa), was biosynthetically incorporated into bacterially prepared recombinant Sup(1-61)-GFP, containing the first 61 residues of Sup35, followed by the green fluorescent protein. Four methionine substitutions and two alanine substitutions were introduced at fixed positions in Sup(1-61) to allow cyanogen bromide cleavage to facilitate subsequent mass spectrometry analysis. Amyloid fibers of pBpa and Met/Ala-substituted Sup(1-61)-GFP were nucleated from purified yeast prion particles of two different strains, namely VK and VL, and shown to faithfully transmit specific strain characteristics to yeast expressing the wild type Sup35 protein. Intra- and intermolecular cross-linking were distinguished by tandem mass spectrometry analysis on fibers seeded from solutions containing equal amounts of (14)N- and (15)N-labeled protein. Fibers propagating the VL strain type exhibited intra- and intermolecular cross-linking between amino acid residues 3 and 28, as well as intra- and intermolecular linking between 32 and 55. Inter- and intramolecular cross-linking between residues 32 and 55 were detected in fibers propagating the VK strain type. Adjacencies of amino acid residues in space revealed by cross-linking were used to constrain possible chain folds of different [PSI] strains.
Collapse
Affiliation(s)
- Shenq-Huey Wong
- From the Molecular Cell Biology, Taiwan International Graduate Program, Academia Sinica and Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan and the Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Chih-Yen King
- the Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| |
Collapse
|
9
|
Kawai S, Murata K. Transformation of Saccharomyces cerevisiae: Spheroplast Method. Fungal Biol 2015. [DOI: 10.1007/978-3-319-10142-2_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
10
|
Exploring the basis of [PIN(+)] variant differences in [PSI(+)] induction. J Mol Biol 2013; 425:3046-59. [PMID: 23770111 DOI: 10.1016/j.jmb.2013.06.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 05/07/2013] [Accepted: 06/07/2013] [Indexed: 01/12/2023]
Abstract
Certain soluble proteins can form amyloid-like prion aggregates. Indeed, the same protein can make different types of aggregates, called variants. Each variant is heritable because it attracts soluble homologous protein to join its aggregate, which is then broken into seeds (propagons) and transmitted to daughter cells. [PSI(+)] and [PIN(+)] are respectively prion forms of Sup35 and Rnq1. Curiously, [PIN(+)] enhances the de novo induction of [PSI(+)]. Different [PIN(+)] variants do this to dramatically different extents. Here, we investigate the mechanism underlying this effect. Consistent with a heterologous prion cross-seeding model, different [PIN(+)] variants preferentially promoted the appearance of different variants of [PSI(+)]. However, we did not detect this specificity in vitro. Also, [PIN(+)] variant cross-seeding efficiencies were not proportional to the level of Rnq1 coimmunocaptured with Sup35 or to the number of [PIN(+)] propagons characteristic for that variant. This leads us to propose that [PIN(+)] variants differ in the cross-seeding quality of their seeds, following the Sup35/[PIN(+)] binding step.
Collapse
|
11
|
Liu CR, Chang CR, Chern Y, Wang TH, Hsieh WC, Shen WC, Chang CY, Chu IC, Deng N, Cohen S, Cheng TH. Spt4 Is Selectively Required for Transcription of Extended Trinucleotide Repeats. Cell 2012; 148:690-701. [DOI: 10.1016/j.cell.2011.12.032] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 10/03/2011] [Accepted: 12/13/2011] [Indexed: 10/28/2022]
|
12
|
Inter-allelic prion propagation reveals conformational relationships among a multitude of [PSI] strains. PLoS Genet 2011; 7:e1002297. [PMID: 21980301 PMCID: PMC3183073 DOI: 10.1371/journal.pgen.1002297] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 07/27/2011] [Indexed: 12/29/2022] Open
Abstract
Immense diversity of prion strains is observed, but its underlying mechanism is less clear. Three [PSI] prion strains--named VH, VK, and VL--were previously isolated in the wild-type yeast genetic background. Here we report the generation and characterization of eight new [PSI] isolates, obtained by propagating the wild-type strains with Sup35 proteins containing single amino-acid alterations. The VH strain splits into two distinct strains when propagated in each of the three genetic backgrounds, harboring respectively single mutations of N21L, R28P, and Gi47 (i.e. insertion of a glycine residue at position 47) on the Sup35 N-terminal prion-forming segment. The six new strains exhibit complex inter-conversion patterns, and one of them continuously mutates into another. However, when they are introduced back into the wild-type background, all 6 strains revert to the VH strain. We obtain two more [PSI] isolates by propagating VK and VL with the Gi47 and N21L backgrounds, respectively. The two isolates do not transmit to other mutant backgrounds but revert to their parental strains in the wild-type background. Our data indicate that a large number of [PSI] strains can be built on three basic Sup35 amyloid structures. It is proposed that the three basic structures differ by chain folding topologies, and sub-strains with the same topology differ in distinct ways by local structural adjustments. This "large number of variations on a small number of basic themes" may also be operative in generating strain diversities in other prion elements. It thus suggests a possible general scheme to classify a multitude of prion strains.
Collapse
|
13
|
Kawai S, Hashimoto W, Murata K. Transformation of Saccharomyces cerevisiae and other fungi: methods and possible underlying mechanism. Bioeng Bugs 2010; 1:395-403. [PMID: 21468206 PMCID: PMC3056089 DOI: 10.4161/bbug.1.6.13257] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 01/25/2010] [Accepted: 08/05/2010] [Indexed: 11/19/2022] Open
Abstract
Transformation (i.e., genetic modification of a cell by the incorporation of exogenous DNA) is indispensable for manipulating fungi. Here, we review the transformation methods for Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candida albicans, Pichia pastoris and Aspergillus species and discuss some common modifications to improve transformation efficiency. We also present a model of the mechanism underlying S. cerevisiae transformation, based on recent reports and the mechanism of transfection in mammalian systems. This model predicts that DNA attaches to the cell wall and enters the cell via endocytotic membrane invagination, although how DNA reaches the nucleus is unknown. Polyethylene glycol is indispensable for successful transformation of intact cells and the attachment of DNA and also possibly acts on the membrane to increase the transformation efficiency. Both lithium acetate and heat shock, which enhance the transformation efficiency of intact cells but not that of spheroplasts, probably help DNA to pass through the cell wall.
Collapse
Affiliation(s)
- Shigeyuki Kawai
- Laboratory of Basic and Applied Molecular Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | | | | |
Collapse
|
14
|
Biochemical, cell biological, and genetic assays to analyze amyloid and prion aggregation in yeast. Methods Enzymol 2010; 470:709-34. [PMID: 20946833 DOI: 10.1016/s0076-6879(10)70030-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Protein aggregates are associated with a variety of debilitating human diseases, but they can have functional roles as well. Both pathological and nonpathological protein aggregates display tremendous diversity, with substantial differences in aggregate size, morphology, and structure. Among the different aggregation types, amyloids are particularly remarkable, because of their high degree of order and their ability to form self-perpetuating conformational states. Amyloids form the structural basis for a group of proteins called prions, which have the ability to generate new phenotypes by a simple switch in protein conformation that does not involve changes in the sequence of the DNA. Although protein aggregates are notoriously difficult to study, recent technological developments and, in particular, the use of yeast prions as model systems, have been very instrumental in understanding fundamental aspects of aggregation. Here, we provide a range of biochemical, cell biological and yeast genetic methods that are currently used in our laboratory to study protein aggregation and the formation of amyloids and prions.
Collapse
|
15
|
Strain-specific sequences required for yeast [PSI+] prion propagation. Proc Natl Acad Sci U S A 2008; 105:13345-50. [PMID: 18757753 DOI: 10.1073/pnas.0802215105] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Amyloid polymorphism underlies the prion strain phenomenon where a single protein polypeptide adopts different chain-folding patterns to form self-propagating cross-beta structures. Three strains of the yeast prion [PSI], namely [VH], [VK], and [VL], have been previously characterized and are amyloid conformers of the yeast translation termination factor Sup35. Here we define specific sequences of the Sup35 protein that are necessary for in vivo propagation of each of these prion strains. By sequential substitution of residues 5-55 of Sup35 by proline and insertion of glycine at alternate sites in this segment, specific mutations have been identified that interfere selectively with the propagation of each of the three prion strains in yeast: the [VH] strain requires amino acid residues 7-21; [VK] requires residues 9-37; and [VL] requires residues 5 to at least 52. Minimal polypeptide segments capable of encoding prion conformations were defined by assembly of recombinant Sup35 fragments on purified prion nuclei to form amyloid fibers in vitro, whose infectivity was assayed in yeast. For the [VK] and [VL] strains, the minimal fragments approximately coincide with the strain-specific sequences defined by mutations of the N-terminal portion of the intact Sup35 (1-685); and for the [VH] strain, a longer Sup (1-53) fragment is required. Polymorphic structures of other amyloids might similarly involve different stretches of polypeptides to form cross-beta amyloid cores with distinct molecular recognition surfaces.
Collapse
|
16
|
Current awareness on yeast. Yeast 2007. [DOI: 10.1002/yea.1325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
|