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Hemagirri M, Chen Y, Gopinath SCB, Adnan M, Patel M, Sasidharan S. RNA-sequencing exploration on SIR2 and SOD genes in Polyalthia longifolia leaf methanolic extracts (PLME) mediated anti-aging effects in Saccharomyces cerevisiae BY611 yeast cells. Biogerontology 2024; 25:705-737. [PMID: 38619670 DOI: 10.1007/s10522-024-10104-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 03/12/2024] [Indexed: 04/16/2024]
Abstract
Polyalthia longifolia is well-known for its abundance of polyphenol content and traditional medicinal uses. Previous research has demonstrated that the methanolic extract of P. longifolia leaves (PLME, 1 mg/mL) possesses anti-aging properties in Saccharomyces cerevisiae BY611 yeast cells. Building on these findings, this study delves deeper into the potential antiaging mechanism of PLME, by analyzing the transcriptional responses of BY611 cells treated with PLME using RNA-sequencing (RNA-seq) technology. The RNA-seq analysis results identified 1691 significantly (padj < 0.05) differentially expressed genes, with 947 upregulated and 744 downregulated genes. Notably, the expression of three important aging-related genes, SIR2, SOD1, and SOD2, showed a significant difference following PLME treatment. The subsequent integration of these targeted genes with GO and KEGG pathway analysis revealed the multifaceted nature of PLME's anti-aging effects in BY611 yeast cells. Enriched GO and KEGG analysis showed that PLME treatment promotes the upregulation of SIR2, SOD1, and SOD2 genes, leading to a boosted cellular antioxidant defense system, reduced oxidative stress, regulated cell metabolism, and maintain genome stability. These collectively increased longevities in PLME-treated BY611 yeast cells and indicate the potential anti-aging action of PLME through the modulation of SIR2 and SOD genes. The present study provided novel insights into the roles of SIR2, SOD1, and SOD2 genes in the anti-aging effects of PLME treatment, offering promising interventions for promoting healthy aging.
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Affiliation(s)
- Manisekaran Hemagirri
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia USM, 11800, Pulau Pinang, Malaysia
| | - Yeng Chen
- Department of Oral & Craniofacial Sciences, Faculty of Dentistry, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Subash C B Gopinath
- Faculty of Chemical Engineering & Technology, Universiti Malaysia Perlis (UniMAP), 02600, Arau, Perlis, Malaysia
- Institute of Nano Electronic Engineering, Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia
- Micro System Technology, Centre of Excellence (CoE), Universiti Malaysia Perlis (UniMAP), Pauh Campus, 02600, Arau, Perlis, Malaysia
- Department of Computer Science and Engineering, Faculty of Science and Information Technology, Daffodil International University, Daffodil Smart City, Birulia, Savar, Dhaka, 1216, Bangladesh
| | - Mohd Adnan
- Department of Biology, College of Science, University of Ha'il, P.O. Box 2440, Ha'il, Saudi Arabia
| | - Mitesh Patel
- Research and Development Cell, Department of Biotechnology, Parul Institute of Applied Sciences, Parul University, Vadodara, 391760, India
| | - Sreenivasan Sasidharan
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia USM, 11800, Pulau Pinang, Malaysia.
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Kim YH, Ryu JI, Devare MN, Jung J, Kim JY. The intricate role of Sir2 in oxidative stress response during the post-diauxic phase in Saccharomyces cerevisiae. Front Microbiol 2023; 14:1285559. [PMID: 38029141 PMCID: PMC10666771 DOI: 10.3389/fmicb.2023.1285559] [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: 08/30/2023] [Accepted: 10/06/2023] [Indexed: 12/01/2023] Open
Abstract
Silent information regulator 2 (Sir2) is a conserved NAD+-dependent histone deacetylase crucial for regulating cellular stress response and the aging process in Saccharomyces cerevisiae. In this study, we investigated the molecular mechanism underlying how the absence of Sir2 can lead to altered stress susceptibilities in S. cerevisiae under different environmental and physiological conditions. In a glucose-complex medium, the sir2Δ strain showed increased sensitivity to H2O2 compared to the wild-type strain during the post-diauxic phase. In contrast, it displayed increased resistance during the exponential growth phase. Transcriptome analysis of yeast cells in the post-diauxic phase indicated that the sir2Δ mutant expressed several oxidative defense genes at lower levels than the wild-type, potentially accounting for its increased susceptibility to H2O2. Interestingly, however, the sir2Δras2Δ double mutant exhibited greater resistance to H2O2 than the ras2Δ single mutant counterpart. We found that the expression regulation of the cytoplasmic catalase encoded by CTT1 was critical for the increased resistance to H2O2 in the sir2Δras2Δ strain. The expression of the CTT1 gene was influenced by the combined effect of RAS2 deletion and the transcription factor Azf1, whose level was modulated by Sir2. These findings provide insights into the importance of understanding the intricate interactions among various factors contributing to cellular stress response.
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Affiliation(s)
| | | | | | | | - Jeong-Yoon Kim
- Department of Microbiology and Molecular Biology, College of Bioscience and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
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Schulze A, Zimmermann A, Kainz K, Egger NB, Bauer MA, Madeo F, Carmona-Gutierrez D. Assessing chronological aging in Saccharomyces cerevisiae. Methods Cell Biol 2023; 181:87-108. [PMID: 38302246 DOI: 10.1016/bs.mcb.2022.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Chronological age represents the time that passes between birth and a given date. To understand the complex network of factors contributing to chronological lifespan, a variety of model organisms have been implemented. One of the best studied organisms is the yeast Saccharomyces cerevisiae, which has greatly contributed toward identifying conserved biological mechanisms that act on longevity. Here, we discuss high- und low-throughput protocols to monitor and characterize chronological lifespan and chronological aging-associated cell death in S. cerevisiae. Included are propidium iodide staining with the possibility to quantitatively assess aging-associated cell death via flow cytometry or qualitative assessments via microscopy, cell viability assessment through plating and cell counting and cell death characterization via propidium iodide/AnnexinV staining and subsequent flow cytometric analysis or microscopy. Importantly, all of these methods combined give a clear picture of the chronological lifespan under different conditions or genetic backgrounds and represent a starting point for pharmacological or genetic interventions.
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Affiliation(s)
- Adina Schulze
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Andreas Zimmermann
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Katharina Kainz
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Nadine B Egger
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Maria A Bauer
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Frank Madeo
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria; Field of Excellence BioHealth, University of Graz, Graz, Austria.
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Wen M, Lan H, Sun R, Chen X, Zhang X, Zhu Z, Tan C, Yuan J, Wang S. Histone deacetylase SirE regulates development, DNA damage response and aflatoxin production in Aspergillus flavus. Environ Microbiol 2022; 24:5596-5610. [PMID: 36059183 DOI: 10.1111/1462-2920.16198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 08/24/2022] [Indexed: 11/28/2022]
Abstract
Aspergillus flavus is a ubiquitous saprotrophic soil-borne pathogenic fungus that causes crops contamination with the carcinogen aflatoxins. Although Sirtuin E (SirE) is known to be a NAD-dependent histone deacetylase involved in global transcriptional regulation. Its biological functions in A. flavus are not fully understood. To explore the effects of SirE, we found that SirE was located in the nucleus and increased the level of H3K56 acetylation. The ΔsirE mutant had the most severe growth defect in the sirtuin family. The RNA-Seq revealed that sirE was crucial for secondary metabolism production as well as genetic information process and oxidation-reduction in A. flavus. Further analysis revealed that the ΔsirE mutant increased aflatoxin production. Both the sirE deletion and H3K56 mutants were highly sensitive to DNA damage and oxidative stresses, indicating that SirE was required for DNA damage and redox reaction by the H3K56 locus. Furthermore, the ΔsirE mutant displayed high sensitivity to osmotic stress and cell wall stress, but they may not be associated with the H3K56. Finally, the catalytic activity site N192 of SirE was required for regulating growth, deacetylase function and aflatoxin production. Together, SirE is essential for histone deacetylation and biological function in A. flavus.
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Affiliation(s)
- Meifang Wen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Huahui Lan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ruilin Sun
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xuan Chen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xin Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zhuo Zhu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Can Tan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jun Yuan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shihua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
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Inactivation of MrSir2 in Monascus ruber Influenced the Developmental Process and the Production of Monascus Azaphilone Pigments. Appl Biochem Biotechnol 2022; 194:5702-5716. [PMID: 35802237 DOI: 10.1007/s12010-022-04030-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2022] [Indexed: 11/02/2022]
Abstract
Monascus species are the producers of Monascus azaphilone pigments (MonAzPs) and lipid-lowering component Monacolin K, which have been widely used as food colorant and health products. In this study, silent information regulator 2 (Sir2) homolog (MrSir2) was characterized, and its impacts on the development and MonAzPs production of Monascus ruber were evaluated. Enzyme activity test in vitro showed that MrSir2 was an NAD+-dependent histone deacetylase. Compared to WT, Δmrsir2 strain accumulated more acetylated lysine residues of histone H3 subunit during its vegetative growth phase, and it exhibited accelerated mycelial aging, more spores, increased resistance to oxidative stress, and more MonAzPs production. RNA-Seq-based transcriptome analysis revealed that MrSir2 mainly regulated the gene expression in macromolecular metabolism such as carbohydrates, proteins, and nucleotides, as well as genes encoding cell wall synthesis and cell membrane component, indicating that MrSir2 probably facilitates the metabolic transition from the primary growth phase to the mycelial aging. Taken together, MrSir2 mainly targets H3 subunit at the vegetative growth phase and affects the development of M. ruber and MonAzPs production.
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Emery SJ, Baker L, Ansell BRE, Mirzaei M, Haynes PA, McConville MJ, Svärd SG, Jex AR. Differential protein expression and post-translational modifications in metronidazole-resistant Giardia duodenalis. Gigascience 2018; 7:4931738. [PMID: 29688452 PMCID: PMC5913674 DOI: 10.1093/gigascience/giy024] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 03/06/2018] [Indexed: 01/20/2023] Open
Abstract
Background Metronidazole (Mtz) is the frontline drug treatment for multiple anaerobic pathogens, including the gastrointestinal protist, Giardia duodenalis. However, treatment failure is common and linked to in vivo drug resistance. In Giardia, in vitro drug-resistant lines allow controlled experimental interrogation of resistance mechanisms in isogenic cultures. However, resistance-associated changes are inconsistent between lines, phenotypic data are incomplete, and resistance is rarely genetically fixed, highlighted by reversion to sensitivity after drug selection ceases or via passage through the life cycle. Comprehensive quantitative approaches are required to resolve isolate variability, fully define Mtz resistance phenotypes, and explore the role of post-translational modifications therein. Findings We performed quantitative proteomics to describe differentially expressed proteins in 3 seminal Mtz-resistant lines compared to their isogenic, Mtz-susceptible, parental line. We also probed changes in post-translational modifications including protein acetylation, methylation, ubiquitination, and phosphorylation via immunoblotting. We quantified more than 1,000 proteins in each genotype, recording substantial genotypic variation in differentially expressed proteins between isotypes. Our data confirm substantial changes in the antioxidant network, glycolysis, and electron transport and indicate links between protein acetylation and Mtz resistance, including cross-resistance to deacetylase inhibitor trichostatin A in Mtz-resistant lines. Finally, we performed the first controlled, longitudinal study of Mtz resistance stability, monitoring lines after cessation of drug selection, revealing isolate-dependent phenotypic plasticity. Conclusions Our data demonstrate understanding that Mtz resistance must be broadened to post-transcriptional and post-translational responses and that Mtz resistance is polygenic, driven by isolate-dependent variation, and is correlated with changes in protein acetylation networks.
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Affiliation(s)
- Samantha J Emery
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
| | - Louise Baker
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Brendan R E Ansell
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Mehdi Mirzaei
- Chemistry and Biomolecular Sciences, Faculty of Science, Macquarie University, North Ryde, NSW, Australia.,Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW, Australia
| | - Paul A Haynes
- Chemistry and Biomolecular Sciences, Faculty of Science, Macquarie University, North Ryde, NSW, Australia
| | - Malcom J McConville
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Staffan G Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Aaron R Jex
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, Australia
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HST1 increases replicative lifespan of a sir2Δ mutant in the absence of PDE2 in Saccharomyces cerevisiae. J Microbiol 2017; 55:123-129. [PMID: 28120189 DOI: 10.1007/s12275-017-6535-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/14/2016] [Accepted: 12/20/2016] [Indexed: 12/14/2022]
Abstract
Silent information regulator 2 (Sir2), which is the founding member of the sirtuin family of proteins, is a pro-longevity factor for replicative lifespan (RLS) in Saccharomyces cerevisiae. Sir2 is required for transcriptional silencing at mating type loci, telomeres, and rDNA loci. Sir2 also represses transcription of highly expressed growth-related genes, such as PMA1 and some ribosomal protein genes. Although the Sir2 paralogues Hst1, Hst2, Hst3, and Hst4 occur in S. cerevisiae, none of them could replace the transcriptional regulation of PMA1 by Sir2 in the wild type. In this study, we demonstrate that Hst1, the closest Sir2 paralogue, deacetylates the acetylated lysine 16 of histone H4 (H4K16Ac) and represses PMA1 transcription in the sir2Δ pde2Δ mutant. We further show that Hst1 plays a role in extending the RLS of the sir2Δ pde2Δ mutant. Collectively, our results suggest that Hst1 can substitute for Sir2 by deacetylating H4K16Ac only in the sir2Δ pde2Δ.
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Meng X, Tan J, Li M, Song S, Miao Y, Zhang Q. Sirt1: Role Under the Condition of Ischemia/Hypoxia. Cell Mol Neurobiol 2016; 37:17-28. [DOI: 10.1007/s10571-016-0355-2] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 02/24/2016] [Indexed: 12/13/2022]
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Kang WK, Kim YH, Kang HA, Kwon KS, Kim JY. Sir2 phosphorylation through cAMP-PKA and CK2 signaling inhibits the lifespan extension activity of Sir2 in yeast. eLife 2015; 4. [PMID: 26329457 PMCID: PMC4586308 DOI: 10.7554/elife.09709] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/02/2015] [Indexed: 01/24/2023] Open
Abstract
Silent information regulator 2 (Sir2), an NAD+-dependent protein deacetylase, has been proposed to be a longevity factor that plays important roles in dietary restriction (DR)-mediated lifespan extension. In this study, we show that the Sir2's role for DR-mediated lifespan extension depends on cAMP-PKA and casein kinase 2 (CK2) signaling in yeast. Sir2 partially represses the transcription of lifespan-associated genes, such as PMA1 (encoding an H+-ATPase) and many ribosomal protein genes, through deacetylation of Lys 16 of histone H4 in the promoter regions of these genes. This repression is relieved by Sir2 S473 phosphorylation, which is mediated by active cAMP-PKA and CK2 signaling. Moderate DR increases the replicative lifespan of wild-type yeast but has no effect on that of yeast expressing the Sir2-S473E or S473A allele, suggesting that the effect of Sir2 on DR-mediated lifespan extension is negatively regulated by S473 phosphorylation. Our results demonstrate a mechanism by which Sir2 contributes to lifespan extension. DOI:http://dx.doi.org/10.7554/eLife.09709.001 We know that cutting calorie intake through a restricted diet can slow down the aging process and prolong the lives of many organisms ranging from yeast to mammals. Calorie restriction also has protective effects on various age-related diseases including neurodegenerative disorders, cardiovascular disease, and cancer. Many studies suggest that we may mimic the beneficial effects of calorie restriction by controlling the activities of some proteins involved in the aging process. An enzyme called Sir2 is required for calorie restriction to be able to increase lifespan. This enzyme modifies proteins called histones, which are used to package DNA inside cells. In yeast, Sir2 modifies the histones in such a way that the genes contained in that section of DNA are inactivated (or ‘silenced’). As the yeast cells age, the activity of Sir2 declines, which allows these genes to become active and contribute to the aging process. However, when yeast cells are grown in the presence of little sugar—which mimics caloric restriction—Sir2 is activated and this restores gene silencing. It is not clear how Sir2's ability to silence these genes contributes to prolonged lifespan. Kang et al. studied the role of Sir2 in yeast and observed that one of the genes that Sir2 inactivates is called PMA1. This gene encodes a protein that is known to restrict the lifespan of yeast cells. Further experiments show that other proteins attach or remove molecules called phosphate groups from Sir2 to regulate its activity. Sir2 is inactivated when a phosphate group is attached, and active in the absence of phosphate. Under a reduced diet, the proteins that add phosphate to Sir2 are inactive, which allows Sir2 to become active and reduce the expression of the PMA1 gene. These results show that Sir2 fine-tunes the expression of PMA1 and other age-related genes and that the attachment of phosphate groups to Sir2 by other proteins interferes with this regulation. The next challenges will be to identify the proteins responsible for attaching phosphate groups to Sir2, and to find out how they work. DOI:http://dx.doi.org/10.7554/eLife.09709.002
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Affiliation(s)
- Woo Kyu Kang
- Department of Microbiology and Molecular Biology, College of Bioscience and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
| | - Yeong Hyeock Kim
- Department of Microbiology and Molecular Biology, College of Bioscience and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
| | - Hyun Ah Kang
- Department of Life Science, Chung-Ang University, Seoul, Republic of Korea
| | - Ki-Sun Kwon
- Aging Intervention Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Jeong-Yoon Kim
- Department of Microbiology and Molecular Biology, College of Bioscience and Biotechnology, Chungnam National University, Daejeon, Republic of Korea
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Michel S, Keller MA, Wamelink MMC, Ralser M. A haploproficient interaction of the transaldolase paralogue NQM1 with the transcription factor VHR1 affects stationary phase survival and oxidative stress resistance. BMC Genet 2015; 16:13. [PMID: 25887987 PMCID: PMC4331311 DOI: 10.1186/s12863-015-0171-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 01/21/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Studying the survival of yeast in stationary phase, known as chronological lifespan, led to the identification of molecular ageing factors conserved from yeast to higher organisms. To identify functional interactions among yeast chronological ageing genes, we conducted a haploproficiency screen on the basis of previously identified long-living mutants. For this, we created a library of heterozygous Saccharomyces cerevisiae double deletion strains and aged them in a competitive manner. RESULTS Stationary phase survival was prolonged in a double heterozygous mutant of the metabolic enzyme non-quiescent mutant 1 (NQM1), a paralogue to the pentose phosphate pathway enzyme transaldolase (TAL1), and the transcription factor vitamin H response transcription factor 1 (VHR1). We find that cells deleted for the two genes possess increased clonogenicity at late stages of stationary phase survival, but find no indication that the mutations delay initial mortality upon reaching stationary phase, canonically defined as an extension of chronological lifespan. We show that both genes influence the concentration of metabolites of glycolysis and the pentose phosphate pathway, central metabolic players in the ageing process, and affect osmolality of growth media in stationary phase cultures. Moreover, NQM1 is glucose repressed and induced in a VHR1 dependent manner upon caloric restriction, on non-fermentable carbon sources, as well as under osmotic and oxidative stress. Finally, deletion of NQM1 is shown to confer resistance to oxidizing substances. CONCLUSIONS The transaldolase paralogue NQM1 and the transcription factor VHR1 interact haploproficiently and affect yeast stationary phase survival. The glucose repressed NQM1 gene is induced under various stress conditions, affects stress resistance and this process is dependent on VHR1. While NQM1 appears not to function in the pentose phosphate pathway, the interplay of NQM1 with VHR1 influences the yeast metabolic homeostasis and stress tolerance during stationary phase, processes associated with yeast ageing.
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Affiliation(s)
- Steve Michel
- Max Planck Institute for Molecular Genetics, Ihnestr 73, Berlin, 14195, Germany.
| | - Markus A Keller
- Department of Biochemistry and Cambridge Systems Biology Center, University of Cambridge, 80, Tennis, Court Road, Cambridge, CB2 1GA, UK.
| | - Mirjam M C Wamelink
- Metabolic Unit, Department of Clinical Chemistry, VU University Medical Centre Amsterdam, Amsterdam, The Netherlands.
| | - Markus Ralser
- Department of Biochemistry and Cambridge Systems Biology Center, University of Cambridge, 80, Tennis, Court Road, Cambridge, CB2 1GA, UK.
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, UK.
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