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Santos SM, Laflin S, Broadway A, Burnet C, Hartheimer J, Rodgers J, Smith DL, Hartman JL. High-resolution yeast quiescence profiling in human-like media reveals complex influences of auxotrophy and nutrient availability. GeroScience 2020; 43:941-964. [PMID: 33015753 PMCID: PMC8110628 DOI: 10.1007/s11357-020-00265-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 09/03/2020] [Indexed: 12/15/2022] Open
Abstract
Yeast cells survive in stationary phase culture by entering quiescence, which is measured by colony-forming capacity upon nutrient re-exposure. Yeast chronological lifespan (CLS) studies, employing the comprehensive collection of gene knockout strains, have correlated weakly between independent laboratories, which is hypothesized to reflect differential interaction between the deleted genes, auxotrophy, media composition, and other assay conditions influencing quiescence. This hypothesis was investigated by high-throughput quiescence profiling of the parental prototrophic strain, from which the gene deletion strain libraries were constructed, and all possible auxotrophic allele combinations in that background. Defined media resembling human cell culture media promoted long-term quiescence and was used to assess effects of glucose, ammonium sulfate, auxotrophic nutrient availability, target of rapamycin signaling, and replication stress. Frequent, high-replicate measurements of colony-forming capacity from cultures aged past 60 days provided profiles of quiescence phenomena such as gasping and hormesis. Media acidification was assayed in parallel to assess correlation. Influences of leucine, methionine, glucose, and ammonium sulfate metabolism were clarified, and a role for lysine metabolism newly characterized, while histidine and uracil perturbations had less impact. Interactions occurred between glucose, ammonium sulfate, auxotrophy, auxotrophic nutrient limitation, aeration, TOR signaling, and/or replication stress. Weak correlation existed between media acidification and maintenance of quiescence. In summary, experimental factors, uncontrolled across previous genome-wide yeast CLS studies, influence quiescence and interact extensively, revealing quiescence as a complex metabolic and developmental process that should be studied in a prototrophic context, omitting ammonium sulfate from defined media, and employing highly replicable protocols.
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Affiliation(s)
- Sean M Santos
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Samantha Laflin
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Audrie Broadway
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Cosby Burnet
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Joline Hartheimer
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - John Rodgers
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Daniel L Smith
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - John L Hartman
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA.
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2
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Tombline G, Millen JI, Polevoda B, Rapaport M, Baxter B, Van Meter M, Gilbertson M, Madrey J, Piazza GA, Rasmussen L, Wennerberg K, White EL, Nitiss JL, Goldfarb DS. Effects of an unusual poison identify a lifespan role for Topoisomerase 2 in Saccharomyces cerevisiae. Aging (Albany NY) 2017; 9:68-97. [PMID: 28077781 PMCID: PMC5310657 DOI: 10.18632/aging.101114] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 10/29/2016] [Indexed: 12/17/2022]
Abstract
A progressive loss of genome maintenance has been implicated as both a cause and consequence of aging. Here we present evidence supporting the hypothesis that an age-associated decay in genome maintenance promotes aging in Saccharomyces cerevisiae (yeast) due to an inability to sense or repair DNA damage by topoisomerase 2 (yTop2). We describe the characterization of LS1, identified in a high throughput screen for small molecules that shorten the replicative lifespan of yeast. LS1 accelerates aging without affecting proliferative growth or viability. Genetic and biochemical criteria reveal LS1 to be a weak Top2 poison. Top2 poisons induce the accumulation of covalent Top2-linked DNA double strand breaks that, if left unrepaired, lead to genome instability and death. LS1 is toxic to cells deficient in homologous recombination, suggesting that the damage it induces is normally mitigated by genome maintenance systems. The essential roles of yTop2 in proliferating cells may come with a fitness trade-off in older cells that are less able to sense or repair yTop2-mediated DNA damage. Consistent with this idea, cells live longer when yTop2 expression levels are reduced. These results identify intrinsic yTop2-mediated DNA damage as a potentially manageable cause of aging.
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Affiliation(s)
- Gregory Tombline
- Biology Department, University of Rochester, Rochester, NY 14627, USA
| | - Jonathan I Millen
- Biology Department, University of Rochester, Rochester, NY 14627, USA
| | - Bogdan Polevoda
- Biology Department, University of Rochester, Rochester, NY 14627, USA
| | - Matan Rapaport
- Biology Department, University of Rochester, Rochester, NY 14627, USA
| | - Bonnie Baxter
- Biology Department, University of Rochester, Rochester, NY 14627, USA
| | - Michael Van Meter
- Biology Department, University of Rochester, Rochester, NY 14627, USA
| | - Matthew Gilbertson
- Department of Biopharmaceutical Sciences, UIC College of Pharmacy at Rockford, Rockford, IL 61107, USA
| | - Joe Madrey
- Drug Discovery Division, Southern Research Institute, Birmingham AL, 35205, USA
| | - Gary A Piazza
- Drug Discovery Division, Southern Research Institute, Birmingham AL, 35205, USA
| | - Lynn Rasmussen
- Drug Discovery Division, Southern Research Institute, Birmingham AL, 35205, USA
| | - Krister Wennerberg
- Drug Discovery Division, Southern Research Institute, Birmingham AL, 35205, USA
| | - E Lucile White
- Drug Discovery Division, Southern Research Institute, Birmingham AL, 35205, USA
| | - John L Nitiss
- Department of Biopharmaceutical Sciences, UIC College of Pharmacy at Rockford, Rockford, IL 61107, USA
| | - David S Goldfarb
- Biology Department, University of Rochester, Rochester, NY 14627, USA
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3
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Cueto-Rojas HF, Milne N, van Helmond W, Pieterse MM, van Maris AJA, Daran JM, Wahl SA. Membrane potential independent transport of NH 3 in the absence of ammonium permeases in Saccharomyces cerevisiae. BMC SYSTEMS BIOLOGY 2017; 11:49. [PMID: 28412970 PMCID: PMC5392931 DOI: 10.1186/s12918-016-0381-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 12/20/2016] [Indexed: 01/08/2023]
Abstract
Background Microbial production of nitrogen containing compounds requires a high uptake flux and assimilation of the N-source (commonly ammonium), which is generally coupled with ATP consumption and negatively influences the product yield. In the industrial workhorse Saccharomyces cerevisiae, ammonium (NH4+) uptake is facilitated by ammonium permeases (Mep1, Mep2 and Mep3), which transport the NH4+ ion, resulting in ATP expenditure to maintain the intracellular charge balance and pH by proton export using the plasma membrane-bound H+-ATPase. Results To decrease the ATP costs for nitrogen assimilation, the Mep genes were removed, resulting in a strain unable to uptake the NH4+ ion. Subsequent analysis revealed that growth of this ∆mep strain was dependent on the extracellular NH3 concentrations. Metabolomic analysis revealed a significantly higher intracellular NHX concentration (3.3-fold) in the ∆mep strain than in the reference strain. Further proteomic analysis revealed significant up-regulation of vacuolar proteases and genes involved in various stress responses. Conclusions Our results suggest that the uncharged species, NH3, is able to diffuse into the cell. The measured intracellular/extracellular NHX ratios under aerobic nitrogen-limiting conditions were consistent with this hypothesis when NHx compartmentalization was considered. On the other hand, proteomic analysis indicated a more pronounced N-starvation stress response in the ∆mep strain than in the reference strain, which suggests that the lower biomass yield of the ∆mep strain was related to higher turnover rates of biomass components. Electronic supplementary material The online version of this article (doi:10.1186/s12918-016-0381-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hugo F Cueto-Rojas
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ, Delft, The Netherlands
| | - Nicholas Milne
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ, Delft, The Netherlands.,Present Address: Evolva Biotech A/S, Lersø Parkallé 42, 2100, København Ø, Denmark
| | - Ward van Helmond
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ, Delft, The Netherlands.,Present Address: Nederlands Forensisch Instituut (NFI), Laan van Ypenburg 6, 2497 GB, Den Haag, The Netherlands
| | - Mervin M Pieterse
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ, Delft, The Netherlands
| | - Antonius J A van Maris
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ, Delft, The Netherlands.,Division of Industrial Biotechnology, School of Biotechnology, KTH Royal Institute of Technology, AlbaNova University Center, SE 106 91, Stockholm, Sweden
| | - Jean-Marc Daran
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ, Delft, The Netherlands.
| | - S Aljoscha Wahl
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629HZ, Delft, The Netherlands.
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4
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Zhao W, Zheng HZ, Zhou T, Hong XS, Cui HJ, Jiang ZW, Chen HJ, Zhou ZJ, Liu XG. CTT1 overexpression increases the replicative lifespan of MMS-sensitive Saccharomyces cerevisiae deficient in KSP1. Mech Ageing Dev 2017; 164:27-36. [PMID: 28347693 DOI: 10.1016/j.mad.2017.03.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 03/06/2017] [Accepted: 03/22/2017] [Indexed: 12/17/2022]
Abstract
Ksplp is a nuclear-localized Ser/Thr kinase that is not essential for the vegetative growth of yeast. A global gene function analysis in yeast suggested that Ksplp was involved in the oxidative stress response; however, the underlying mechanism remains unclear. Here, we showed that KSP1-deficient yeast cells exhibit hypersensitivity to the DNA alkylating agent methyl methanesulphonate (MMS), and treatment of the KSP1-deficient strain with MMS could trigger abnormal mitochondrial membrane potential and up-regulate reactive oxygen species (ROS) production. In addition, the mRNA expression level of the catalase gene CTT1 (which encodes cytosolic catalase) and total catalase activity were strongly down-regulated in the KSP1-deleted strain compared with those in wild-type cells. Moreover, the KSP1 deficiency also leads to a shortened replicative lifespan, which could be restored by the increased expression of CTT1. On the other hand, KSP1-overexpressed (KSP1OX) yeast cells exhibited increased resistance towards MMS, an effect that was, at least in part, CTT1 independent. Collectively, these findings highlight the involvement of Ksplp in the DNA damage response and implicate Ksplp as a modulator of the replicative lifespan.
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Affiliation(s)
- Wei Zhao
- Institute of Aging Research, Guangdong Medical University, Dongguan 523808, China; Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan 523808, China
| | - Hua-Zhen Zheng
- Institute of Aging Research, Guangdong Medical University, Dongguan 523808, China; Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan 523808, China
| | - Tao Zhou
- Institute of Aging Research, Guangdong Medical University, Dongguan 523808, China; Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan 523808, China
| | - Xiao-Shan Hong
- Institute of Gynecology, Women and Children's Hospital of Guangdong Province, Guangzhou 511442, China
| | - Hong-Jing Cui
- Institute of Aging Research, Guangdong Medical University, Dongguan 523808, China; Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan 523808, China
| | - Zhi-Wen Jiang
- Institute of Aging Research, Guangdong Medical University, Dongguan 523808, China; Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan 523808, China
| | - Hui-Ji Chen
- Institute of Aging Research, Guangdong Medical University, Dongguan 523808, China; Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan 523808, China
| | - Zhong-Jun Zhou
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Xin-Guang Liu
- Institute of Aging Research, Guangdong Medical University, Dongguan 523808, China; Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, Dongguan 523808, China; Institute of Biochemistry and Molecular Biology, Guangdong Medical University, Dongguan 523808, China.
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5
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Güven E, Parnell LA, Jackson ED, Parker MC, Gupta N, Rodrigues J, Qin H. Hydrogen peroxide induced loss of heterozygosity correlates with replicative lifespan and mitotic asymmetry in Saccharomyces cerevisiae. PeerJ 2016; 4:e2671. [PMID: 27833823 PMCID: PMC5101604 DOI: 10.7717/peerj.2671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 10/09/2016] [Indexed: 01/28/2023] Open
Abstract
Cellular aging in Saccharomyces cerevisiae can lead to genomic instability and impaired mitotic asymmetry. To investigate the role of oxidative stress in cellular aging, we examined the effect of exogenous hydrogen peroxide on genomic instability and mitotic asymmetry in a collection of yeast strains with diverse backgrounds. We treated yeast cells with hydrogen peroxide and monitored the changes of viability and the frequencies of loss of heterozygosity (LOH) in response to hydrogen peroxide doses. The mid-transition points of viability and LOH were quantified using sigmoid mathematical functions. We found that the increase of hydrogen peroxide dependent genomic instability often occurs before a drop in viability. We previously observed that elevation of genomic instability generally lags behind the drop in viability during chronological aging. Hence, onset of genomic instability induced by exogenous hydrogen peroxide treatment is opposite to that induced by endogenous oxidative stress during chronological aging, with regards to the midpoint of viability. This contrast argues that the effect of endogenous oxidative stress on genome integrity is well suppressed up to the dying-off phase during chronological aging. We found that the leadoff of exogenous hydrogen peroxide induced genomic instability to viability significantly correlated with replicative lifespan (RLS), indicating that yeast cells' ability to counter oxidative stress contributes to their replicative longevity. Surprisingly, this leadoff is positively correlated with an inverse measure of endogenous mitotic asymmetry, indicating a trade-off between mitotic asymmetry and cell's ability to fend off hydrogen peroxide induced oxidative stress. Overall, our results demonstrate strong associations of oxidative stress to genomic instability and mitotic asymmetry at the population level of budding yeast.
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Affiliation(s)
- Emine Güven
- Department of Biology, Spelman College, Atlanta, Georgia, United States
- Current affiliation: Department of Computer Science and Engineering, University of Tennessee at Chattanooga, Chattanooga, Tennessee, United States
| | - Lindsay A. Parnell
- Department of Biology, Spelman College, Atlanta, Georgia, United States
- Current affiliation: Program of Molecular Genetics and Genomics, Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri, United States
| | - Erin D. Jackson
- Department of Biology, Spelman College, Atlanta, Georgia, United States
| | - Meighan C. Parker
- Department of Biology, Spelman College, Atlanta, Georgia, United States
| | - Nilin Gupta
- Department of Biology, Spelman College, Atlanta, Georgia, United States
| | - Jenny Rodrigues
- Department of Biology, Spelman College, Atlanta, Georgia, United States
| | - Hong Qin
- Department of Biology, Spelman College, Atlanta, Georgia, United States
- Current affiliation: Department of Computer Science and Engineering, Department of Biology, Geology, and Environmental Science, SimCenter, University of Tennessee at Chattanooga, Chattanooga, Tennessee, United States
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6
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Kim Y, Nam HG, Valenzano DR. The short-lived African turquoise killifish: an emerging experimental model for ageing. Dis Model Mech 2016; 9:115-29. [PMID: 26839399 PMCID: PMC4770150 DOI: 10.1242/dmm.023226] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Human ageing is a fundamental biological process that leads to functional decay, increased risk for various diseases and, ultimately, death. Some of the basic biological mechanisms underlying human ageing are shared with other organisms; thus, animal models have been invaluable in providing key mechanistic and molecular insights into the common bases of biological ageing. In this Review, we briefly summarise the major applications of the most commonly used model organisms adopted in ageing research and highlight their relevance in understanding human ageing. We compare the strengths and limitations of different model organisms and discuss in detail an emerging ageing model, the short-lived African turquoise killifish. We review the recent progress made in using the turquoise killifish to study the biology of ageing and discuss potential future applications of this promising animal model.
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Affiliation(s)
- Yumi Kim
- Max Planck Institute for Biology of Ageing, D50931, Cologne, Germany Department of New Biology, DGIST, 711-873, Daegu, Republic of Korea
| | - Hong Gil Nam
- Department of New Biology, DGIST, 711-873, Daegu, Republic of Korea Center for Plant Aging Research, Institute for Basic Science, 711-873, Daegu, Republic of Korea
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7
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Falcone C, Mazzoni C. External and internal triggers of cell death in yeast. Cell Mol Life Sci 2016; 73:2237-50. [PMID: 27048816 PMCID: PMC4887522 DOI: 10.1007/s00018-016-2197-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 03/18/2016] [Indexed: 01/30/2023]
Abstract
In recent years, yeast was confirmed as a useful eukaryotic model system to decipher the complex mechanisms and networks occurring in higher eukaryotes, particularly in mammalian cells, in physiological as well in pathological conditions. This article focuses attention on the contribution of yeast in the study of a very complex scenario, because of the number and interconnection of pathways, represented by cell death. Yeast, although it is a unicellular organism, possesses the basal machinery of different kinds of cell death occurring in higher eukaryotes, i.e., apoptosis, regulated necrosis and autophagy. Here we report the current knowledge concerning the yeast orthologs of main mammalian cell death regulators and executors, the role of organelles and compartments, and the cellular phenotypes observed in the different forms of cell death in response to external and internal triggers. Thanks to the ease of genetic manipulation of this microorganism, yeast strains expressing human genes that promote or counteract cell death, onset of tumors and neurodegenerative diseases have been constructed. The effects on yeast cells of some of these genes are also presented.
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Affiliation(s)
- Claudio Falcone
- Pasteur Institute-Cenci Bolognetti Foundation; Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Cristina Mazzoni
- Pasteur Institute-Cenci Bolognetti Foundation; Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
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8
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Extension of Saccharomyces paradoxus chronological lifespan by retrotransposons in certain media conditions is associated with changes in reactive oxygen species. Genetics 2014; 198:531-45. [PMID: 25106655 DOI: 10.1534/genetics.114.168799] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Retrotransposons are mobile DNA elements present throughout eukaryotic genomes that can cause mutations and genome rearrangements when they replicate through reverse transcription. Increased expression and/or mobility of retrotransposons has been correlated with aging in yeast, Caenorhabditis elegans, Drosophila melanogaster, and mammals. The many copies of retrotransposons in humans and various model organisms complicate further pursuit of this relationship. The Saccharomyces cerevisiae Ty1 retrotransposon was introduced into a strain of S. paradoxus that completely lacks retrotransposons to compare chronological lifespans (CLSs) of yeast strains with zero, low, or high Ty1 copy number. Yeast chronological lifespan reflects the progressive loss of cell viability in a nondividing state. Chronological lifespans for the strains were not different in rich medium, but were extended in high Ty1 copy-number strains in synthetic medium and in rich medium containing a low dose of hydroxyurea (HU), an agent that depletes deoxynucleoside triphosphates. Lifespan extension was not strongly correlated with Ty1 mobility or mutation rates for a representative gene. Buffering deoxynucleoside triphosphate levels with threonine supplementation did not substantially affect this lifespan extension, and no substantial differences in cell cycle arrest in the nondividing cells were observed. Lifespan extension was correlated with reduced reactive oxygen species during early stationary phase in high Ty1 copy strains, and antioxidant treatment allowed the zero Ty1 copy strain to live as long as high Ty1 copy-number strains in rich medium with hydroxyurea. This exceptional yeast system has identified an unexpected longevity-promoting role for retrotransposons that may yield novel insights into mechanisms regulating lifespan.
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9
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Oling D, Masoom R, Kvint K. Loss of Ubp3 increases silencing, decreases unequal recombination in rDNA, and shortens the replicative life span in Saccharomyces cerevisiae. Mol Biol Cell 2014; 25:1916-24. [PMID: 24760971 PMCID: PMC4055270 DOI: 10.1091/mbc.e13-10-0591] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Ubp3 is an antisilencing factor. Accordingly, loss of Upb3 leads to lower RNAPII occupancy in heterochromatic regions and suppression of unequal recombination in rDNA. However, ubp3Δ mutants have a shortened replicative life span, suggesting that recombination frequency is not directly correlated with aging. Ubp3 is a conserved ubiquitin protease that acts as an antisilencing factor in MAT and telomeric regions. Here we show that ubp3∆ mutants also display increased silencing in ribosomal DNA (rDNA). Consistent with this, RNA polymerase II occupancy is lower in cells lacking Ubp3 than in wild-type cells in all heterochromatic regions. Moreover, in a ubp3∆ mutant, unequal recombination in rDNA is highly suppressed. We present genetic evidence that this effect on rDNA recombination, but not silencing, is entirely dependent on the silencing factor Sir2. Further, ubp3∆ sir2∆ mutants age prematurely at the same rate as sir2∆ mutants. Thus our data suggest that recombination negatively influences replicative life span more so than silencing. However, in ubp3∆ mutants, recombination is not a prerequisite for aging, since cells lacking Ubp3 have a shorter life span than isogenic wild-type cells. We discuss the data in view of different models on how silencing and unequal recombination affect replicative life span and the role of Ubp3 in these processes.
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Affiliation(s)
- David Oling
- Department of Chemistry and Molecular Biology, University of Gothenburg, 413 90 Gothenburg, Sweden
| | - Rehan Masoom
- Department of Chemistry and Molecular Biology, University of Gothenburg, 413 90 Gothenburg, Sweden
| | - Kristian Kvint
- Department of Chemistry and Molecular Biology, University of Gothenburg, 413 90 Gothenburg, Sweden
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10
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Swinnen E, Ghillebert R, Wilms T, Winderickx J. Molecular mechanisms linking the evolutionary conserved TORC1-Sch9 nutrient signalling branch to lifespan regulation in Saccharomyces cerevisiae. FEMS Yeast Res 2013; 14:17-32. [PMID: 24102693 DOI: 10.1111/1567-1364.12097] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 07/09/2013] [Accepted: 09/06/2013] [Indexed: 01/13/2023] Open
Abstract
The knowledge on the molecular aspects regulating ageing in eukaryotic organisms has benefitted greatly from studies using the budding yeast Saccharomyces cerevisiae. Indeed, many aspects involved in the control of lifespan appear to be well conserved among species. Of these, the lifespan-extending effects of calorie restriction (CR) and downregulation of nutrient signalling through the target of rapamycin (TOR) pathway are prime examples. Here, we present an overview on the molecular mechanisms by which these interventions mediate lifespan extension in yeast. Several models have been proposed in the literature, which should be seen as complementary, instead of contradictory. Results indicate that CR mediates a large amount of its effect by downregulating signalling through the TORC1-Sch9 branch. In addition, we note that Sch9 is more than solely a downstream effector of TORC1, and documented connections with sphingolipid metabolism may be particularly interesting for future research on ageing mechanisms. As Sch9 comprises the yeast orthologue of the mammalian PKB/Akt and S6K1 kinases, future studies in yeast may continue to serve as an attractive model to elucidate conserved mechanisms involved in ageing and age-related diseases in humans.
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11
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Weinberger M, Sampaio-Marques B, Ludovico P, Burhans WC. DNA replication stress-induced loss of reproductive capacity in S. cerevisiae and its inhibition by caloric restriction. Cell Cycle 2013; 12:1189-200. [PMID: 23518504 DOI: 10.4161/cc.24232] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In many organisms, attenuation of growth signaling by caloric restriction or mutational inactivation of growth signaling pathways extends lifespan and protects against cancer and other age-related diseases. The focus of many efforts to understand these effects has been on the induction of oxidative stress defenses that inhibit cellular senescence and cell death. Here we show that in the model organism S. cerevisiae, growth signaling induces entry of cells in stationary phase into S phase in parallel with loss of reproductive capacity, which is enhanced by elevated concentrations of glucose. Overexpression of RNR1 encoding a ribonucleotide reductase subunit required for the synthesis of deoxynucleotide triphosphates and DNA replication suppresses the accelerated loss of reproductive capacity of cells cultured in high glucose. The reduced reproductive capacity of these cells is also suppressed by excess threonine, which buffers dNTP pools when ribonucleotide reductase activity is limiting. Caloric restriction or inactivation of the AKT homolog Sch9p inhibits senescence and death in stationary phase cells caused by the DNA replication inhibitor hydroxyurea or by inactivation of the DNA replication and repair proteins Sgs1p or Rad27p. Inhibition of DNA replication stress represents a novel mechanism by which caloric restriction promotes longevity in S. cerevisiae. A similar mechanism may promote longevity and inhibit cancer and other age-related diseases in humans.
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Affiliation(s)
- Martin Weinberger
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, NY, USA
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12
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Farrugia G, Balzan R. Oxidative stress and programmed cell death in yeast. Front Oncol 2012; 2:64. [PMID: 22737670 PMCID: PMC3380282 DOI: 10.3389/fonc.2012.00064] [Citation(s) in RCA: 187] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 06/02/2012] [Indexed: 12/11/2022] Open
Abstract
Yeasts, such as Saccharomyces cerevisiae, have long served as useful models for the study of oxidative stress, an event associated with cell death and severe human pathologies. This review will discuss oxidative stress in yeast, in terms of sources of reactive oxygen species (ROS), their molecular targets, and the metabolic responses elicited by cellular ROS accumulation. Responses of yeast to accumulated ROS include upregulation of antioxidants mediated by complex transcriptional changes, activation of pro-survival pathways such as mitophagy, and programmed cell death (PCD) which, apart from apoptosis, includes pathways such as autophagy and necrosis, a form of cell death long considered accidental and uncoordinated. The role of ROS in yeast aging will also be discussed.
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Affiliation(s)
- Gianluca Farrugia
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of MaltaMsida, Malta
| | - Rena Balzan
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of MaltaMsida, Malta
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