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Xian F, Yang L, Ye H, Xu J, Yue X, Wang X. Revealing the Mechanism of Aroma Production Driven by High Salt Stress in Trichomonascus ciferrii WLW. Foods 2024; 13:1593. [PMID: 38890822 PMCID: PMC11172348 DOI: 10.3390/foods13111593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 06/20/2024] Open
Abstract
Douchi is a Chinese traditional fermented food with a unique flavor. Methyl anthranilate (MA) plays an important role in formation of this flavor. However, the complicated relationship between the MA formation and the metabolic mechanism of the key functional microorganisms remains unclear. Here, we elucidated the response mechanism of aroma production driven by high salt stress in Trichomonascus ciferrii WLW (T. ciferrii WLW), which originates from the douchi fermentation process. The highest production of MA was obtained in a 10% NaCl environment. The enhanced expression of the key enzyme genes of the pentose phosphate pathway and shikimic acid pathway directed carbon flow toward aromatic amino acid synthesis and helped sustain an increased expression of metK to synthesize a large amount of the methyl donor S-adenosylmethionine, which promoted methyl anthranilate yield. This provides a theoretical basis for in-depth research on the applications of the flavor formation mechanisms of fermented foods.
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Affiliation(s)
- Fangying Xian
- School of Life Science (Health), Jiangxi Normal University, Nanchang 330022, China; (F.X.); (L.Y.); (H.Y.); (J.X.)
| | - Lin Yang
- School of Life Science (Health), Jiangxi Normal University, Nanchang 330022, China; (F.X.); (L.Y.); (H.Y.); (J.X.)
- College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022, China
| | - Huaqing Ye
- School of Life Science (Health), Jiangxi Normal University, Nanchang 330022, China; (F.X.); (L.Y.); (H.Y.); (J.X.)
| | - Jinlin Xu
- School of Life Science (Health), Jiangxi Normal University, Nanchang 330022, China; (F.X.); (L.Y.); (H.Y.); (J.X.)
| | - Xiaoping Yue
- College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022, China
| | - Xiaolan Wang
- School of Life Science (Health), Jiangxi Normal University, Nanchang 330022, China; (F.X.); (L.Y.); (H.Y.); (J.X.)
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2
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Sharda A, Humphrey TC. The role of histone H3K36me3 writers, readers and erasers in maintaining genome stability. DNA Repair (Amst) 2022; 119:103407. [PMID: 36155242 DOI: 10.1016/j.dnarep.2022.103407] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 09/15/2022] [Accepted: 09/15/2022] [Indexed: 11/03/2022]
Abstract
Histone Post-Translational Modifications (PTMs) play fundamental roles in mediating DNA-related processes such as transcription, replication and repair. The histone mark H3K36me3 and its associated methyltransferase SETD2 (Set2 in yeast) are archetypical in this regard, performing critical roles in each of these DNA transactions. Here, we present an overview of H3K36me3 regulation and the roles of its writers, readers and erasers in maintaining genome stability through facilitating DNA double-strand break (DSB) repair, checkpoint signalling and replication stress responses. Further, we consider how loss of SETD2 and H3K36me3, frequently observed in a number of different cancer types, can be specifically targeted in the clinic through exploiting loss of particular genome stability functions.
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Affiliation(s)
- Asmita Sharda
- CRUK and MRC Oxford Institute for Radiation Oncology, Old Road Campus Research Building, University of Oxford, Oxford OX3 7DQ, UK
| | - Timothy C Humphrey
- CRUK and MRC Oxford Institute for Radiation Oncology, Old Road Campus Research Building, University of Oxford, Oxford OX3 7DQ, UK
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3
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Chatfield-Reed K, Marno Jones K, Shah F, Chua G. Genetic-interaction screens uncover novel biological roles and regulators of transcription factors in fission yeast. G3 GENES|GENOMES|GENETICS 2022; 12:6655692. [PMID: 35924983 PMCID: PMC9434175 DOI: 10.1093/g3journal/jkac194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/20/2022] [Indexed: 12/05/2022]
Abstract
In Schizosaccharomyces pombe, systematic analyses of single transcription factor deletion or overexpression strains have made substantial advances in determining the biological roles and target genes of transcription factors, yet these characteristics are still relatively unknown for over a quarter of them. Moreover, the comprehensive list of proteins that regulate transcription factors remains incomplete. To further characterize Schizosaccharomyces pombe transcription factors, we performed synthetic sick/lethality and synthetic dosage lethality screens by synthetic genetic array. Examination of 2,672 transcription factor double deletion strains revealed a sick/lethality interaction frequency of 1.72%. Phenotypic analysis of these sick/lethality strains revealed potential cell cycle roles for several poorly characterized transcription factors, including SPBC56F2.05, SPCC320.03, and SPAC3C7.04. In addition, we examined synthetic dosage lethality interactions between 14 transcription factors and a miniarray of 279 deletion strains, observing a synthetic dosage lethality frequency of 4.99%, which consisted of known and novel transcription factor regulators. The miniarray contained deletions of genes that encode primarily posttranslational-modifying enzymes to identify putative upstream regulators of the transcription factor query strains. We discovered that ubiquitin ligase Ubr1 and its E2/E3-interacting protein, Mub1, degrade the glucose-responsive transcriptional repressor Scr1. Loss of ubr1+ or mub1+ increased Scr1 protein expression, which resulted in enhanced repression of flocculation through Scr1. The synthetic dosage lethality screen also captured interactions between Scr1 and 2 of its known repressors, Sds23 and Amk2, each affecting flocculation through Scr1 by influencing its nuclear localization. Our study demonstrates that sick/lethality and synthetic dosage lethality screens can be effective in uncovering novel functions and regulators of Schizosaccharomyces pombe transcription factors.
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Affiliation(s)
- Kate Chatfield-Reed
- Department of Biological Sciences, University of Calgary , Calgary, Alberta T2N 1N4, Canada
| | - Kurtis Marno Jones
- Department of Biological Sciences, University of Calgary , Calgary, Alberta T2N 1N4, Canada
| | - Farah Shah
- Department of Biological Sciences, University of Calgary , Calgary, Alberta T2N 1N4, Canada
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4
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González-Medina A, Pazo E, Hidalgo E, Ayté J. SWI/SNF and RSC remodeler complexes bind to MBF-dependent genes. Cell Cycle 2021; 20:2652-2661. [PMID: 34843421 DOI: 10.1080/15384101.2021.2008203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
In fission yeast, MBF-dependent transcription is required for cells to complete S phase. The MBF transcription factor is regulated through a complex feedback mechanism that involves the co-repressors Yox1 and Nrm1 that are loaded onto MBF at the end of S phase, while positive transactivation is achieved through the constitutive binding of the co-activator Rep2. Here we show that Rep2 is required to fully recruit the chromatin remodelers SWI/SNF and RSC to MBF-regulated promoters. On the contrary, Nrm1 and Yox1, when bound to the MBF complex, block the approximation of these chromatin remodelers to MBF-regulated promoters. We propose that SWI/SNF and RSC are recruited to MBF-regulated genes, and RSC together with SAGA complex are important to regulate the G1-to-S transcriptional wave. Mutants of these remodeler complexes are highly sensitive when cells are exposed to insults that challenge DNA synthesis.
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Affiliation(s)
| | - Esther Pazo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
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5
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Hümmer S, Borao S, Guerra-Moreno A, Cozzuto L, Hidalgo E, Ayté J. Cross talk between the upstream exon-intron junction and Prp2 facilitates splicing of non-consensus introns. Cell Rep 2021; 37:109893. [PMID: 34706246 DOI: 10.1016/j.celrep.2021.109893] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 04/27/2021] [Accepted: 10/06/2021] [Indexed: 10/20/2022] Open
Abstract
Splicing of mRNA precursors is essential in the regulation of gene expression. U2AF65 recognizes the poly-pyrimidine tract and helps in the recognition of the branch point. Inactivation of fission yeast U2AF65 (Prp2) blocks splicing of most, but not all, pre-mRNAs, for reasons that are not understood. Here, we have determined genome-wide the splicing efficiency of fission yeast cells as they progress into synchronous meiosis in the presence or absence of functional Prp2. Our data indicate that in addition to the splicing elements at the 3' end of any intron, the nucleotides immediately upstream the intron will determine whether Prp2 is required or dispensable for splicing. By changing those nucleotides in any given intron, we regulate its Prp2 dependency. Our results suggest a model in which Prp2 is required for the coordinated recognition of both intronic ends, placing Prp2 as a key regulatory element in the determination of the exon-intron boundaries.
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Affiliation(s)
- Stefan Hümmer
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain.
| | - Sonia Borao
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Angel Guerra-Moreno
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Luca Cozzuto
- CRG Bioinformatics Core, Centre de Regulació Genòmica (CRG), 08003 Barcelona, Spain
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain.
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6
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The S. pombe CDK5 Orthologue Pef1 Cooperates with Three Cyclins, Clg1, Pas1 and Psl1, to Promote Pre-Meiotic DNA Replication. Biomolecules 2021; 11:biom11010089. [PMID: 33445784 PMCID: PMC7828282 DOI: 10.3390/biom11010089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 01/05/2021] [Accepted: 01/08/2021] [Indexed: 12/11/2022] Open
Abstract
Meiosis is a specialized cell division process that mediates genetic information transfer to the next generation. Meiotic chromosomal segregation occurs when DNA replication is completed during the pre-meiotic S phase. Here, we show that Schizosaccharomyces pombe Pef1, an orthologue of mammalian cyclin-dependent kinase 5 (CDK5), is required to promote pre-meiotic DNA replication. We examined the efficiency of meiotic initiation using pat1-114 mutants and found that, meiotic nuclear divisions did not occur in the pef1Δ pat1-114 strain. Deletion of pef1 also suppressed the expression of DNA replication factors and the phosphorylation of Cdc2 Tyr-15. The double deletion of clg1 and psl1 arrested meiotic initiation in pat1-114 mutant cells, similar to that of pef1-deficient cells. Meiotic progression was also slightly delayed in the pas1-deficient strain. Our results reveal that Pef1 regulates cyclin-coordinated meiotic progression.
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7
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González-Medina A, Hidalgo E, Ayté J. Gcn5-mediated acetylation at MBF-regulated promoters induces the G1/S transcriptional wave. Nucleic Acids Res 2019; 47:8439-8451. [PMID: 31260531 PMCID: PMC6895280 DOI: 10.1093/nar/gkz561] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 06/17/2019] [Accepted: 06/21/2019] [Indexed: 11/26/2022] Open
Abstract
In fission yeast, MBF-dependent transcription is inactivated at the end of S phase through a negative feedback loop that involves the co-repressors, Yox1 and Nrm1. Although this repression system is well known, the molecular mechanisms involved in MBF activation remain largely unknown. Compacted chromatin constitutes a barrier to activators accessing promoters. Here, we show that chromatin regulation plays a key role in activating MBF-dependent transcription. Gcn5, a part of the SAGA complex, binds to MBF-regulated promoters through the MBF co-activator Rep2 in a cell cycle-dependent manner and in a reverse correlation to the binding of the MBF co-repressors, Nrm1 or Yox1. We propose that the co-repressors function as physical barriers to SAGA recruitment onto MBF promoters. We also show that Gcn5 acetylates specific lysine residues on histone H3 in a cell cycle-regulated manner. Furthermore, either in a gcn5 mutant or in a strain in which histone H3 is kept in an unacetylated form, MBF-dependent transcription is downregulated. In summary, Gcn5 is required for the full activation and correct timing of MBF-regulated gene transcription.
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Affiliation(s)
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona 08003, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona 08003, Spain
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8
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Silva E, Ideker T. Transcriptional responses to DNA damage. DNA Repair (Amst) 2019; 79:40-49. [PMID: 31102970 PMCID: PMC6570417 DOI: 10.1016/j.dnarep.2019.05.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/20/2019] [Accepted: 05/04/2019] [Indexed: 12/31/2022]
Abstract
In response to the threat of DNA damage, cells exhibit a dramatic and multi-factorial response spanning from transcriptional changes to protein modifications, collectively known as the DNA damage response (DDR). Here, we review the literature surrounding the transcriptional response to DNA damage. We review differences in observed transcriptional responses as a function of cell cycle stage and emphasize the importance of experimental design in these transcriptional response studies. We additionally consider topics including structural challenges in the transcriptional response to DNA damage as well as the connection between transcription and protein abundance.
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Affiliation(s)
- Erica Silva
- Department of Medicine, University of California San Diego, La Jolla, California, USA; Biomedical Sciences Program, University of California San Diego, La Jolla, California, USA.
| | - Trey Ideker
- Department of Medicine, University of California San Diego, La Jolla, California, USA; Biomedical Sciences Program, University of California San Diego, La Jolla, California, USA; Program in Bioinformatics, University of California San Diego, La Jolla, California, USA; Department of Bioengineering, University of California San Diego, La Jolla, California, USA.
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9
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Down-regulation of Cdk1 activity in G1 coordinates the G1/S gene expression programme with genome replication. Curr Genet 2019; 65:685-690. [DOI: 10.1007/s00294-018-00926-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 12/20/2018] [Accepted: 12/22/2018] [Indexed: 02/07/2023]
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10
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Rubio A, García-Blanco N, Vázquez-Bolado A, Belén Suárez M, Moreno S. Nutritional cell cycle reprogramming reveals that inhibition of Cdk1 is required for proper MBF-dependent transcription. J Cell Sci 2018; 131:jcs.218743. [PMID: 30154212 DOI: 10.1242/jcs.218743] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 08/20/2018] [Indexed: 01/22/2023] Open
Abstract
In nature, cells and in particular unicellular microorganisms are exposed to a variety of nutritional environments. Fission yeast cells cultured in nitrogen-rich media grow fast, divide with a large size and show a short G1 and a long G2. However, when cultured in nitrogen-poor media, they exhibit reduced growth rate and cell size and a long G1 and a short G2. In this study, we compared the phenotypes of cells lacking the highly conserved cyclin-dependent kinase (Cdk) inhibitor Rum1 and the anaphase-promoting complex/cyclosome (APC/C) activator Ste9 in nitrogen-rich and nitrogen-poor media. Rum1 and Ste9 are dispensable for cell division in nitrogen-rich medium. However, in nitrogen-poor medium they are essential for generating a proper wave of MluI cell-cycle box binding factor (MBF)-dependent transcription at the end of G1, which is crucial for promoting a successful S phase. Mutants lacking Rum1 and Ste9 showed premature entry into S phase and a reduced wave of MBF-dependent transcription, leading to replication stress, DNA damage and G2 cell cycle arrest. This work demonstrates how reprogramming the cell cycle by changing the nutritional environment may reveal new roles for cell cycle regulators.
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Affiliation(s)
- Angela Rubio
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain.,Department of Microbiology and Genetics, University of Salamanca, 37007 Salamanca. Spain
| | - Natalia García-Blanco
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain.,Department of Microbiology and Genetics, University of Salamanca, 37007 Salamanca. Spain
| | - Alicia Vázquez-Bolado
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain.,Department of Microbiology and Genetics, University of Salamanca, 37007 Salamanca. Spain
| | - María Belén Suárez
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain.,Department of Microbiology and Genetics, University of Salamanca, 37007 Salamanca. Spain
| | - Sergio Moreno
- Instituto de Biología Funcional y Genómica, CSIC, University of Salamanca, 37007 Salamanca, Spain
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11
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Knezevic I, González-Medina A, Gaspa L, Hidalgo E, Ayté J. The INO80 complex activates the transcription of S-phase genes in a cell cycle-regulated manner. FEBS J 2018; 285:3870-3881. [PMID: 30134042 DOI: 10.1111/febs.14640] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 07/30/2018] [Accepted: 08/20/2018] [Indexed: 12/13/2022]
Abstract
Chromatin structure is an essential factor in the proper regulation of DNA repair, DNA replication and transcription. The INO80 complex and the SWR complex have been shown to play a fundamental role in transcription regulation through remodeling chromatin at specific genes and loci. Here, we report that the Schizosaccharomyces pombe INO80 complex physically interacts with the mlui-binding factor (MBF) complex. Furthermore, we are able to detect the INO80 complex in MBF-regulated promoters. Binding of INO80 to these genes is cell cycle regulated, with a maximum binding preceding their transcription and accumulation of their mRNAs. In fact, the INO80 complex is required to fully and timely activate the transcription of these genes. We also show that the accumulation of acetylated H2A.Z at the +1 nucleosome is cell cycle regulated. Cells in which H2A.Z acetylation is abolished still have some cell cycle-regulated transcription of MBF-dependent genes, although to a much lesser extent.
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Affiliation(s)
- Iva Knezevic
- Departament de Ciències, Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
| | - Alberto González-Medina
- Departament de Ciències, Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
| | - Laura Gaspa
- Departament de Ciències, Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
| | - Elena Hidalgo
- Departament de Ciències, Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
| | - José Ayté
- Departament de Ciències, Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
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12
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Loll-Krippleber R, Brown GW. P-body proteins regulate transcriptional rewiring to promote DNA replication stress resistance. Nat Commun 2017; 8:558. [PMID: 28916784 PMCID: PMC5601920 DOI: 10.1038/s41467-017-00632-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 07/12/2017] [Indexed: 12/12/2022] Open
Abstract
mRNA-processing (P-) bodies are cytoplasmic granules that form in eukaryotic cells in response to numerous stresses to serve as sites of degradation and storage of mRNAs. Functional P-bodies are critical for the DNA replication stress response in yeast, yet the repertoire of P-body targets and the mechanisms by which P-bodies promote replication stress resistance are unknown. In this study we identify the complete complement of mRNA targets of P-bodies during replication stress induced by hydroxyurea treatment. The key P-body protein Lsm1 controls the abundance of HHT1, ACF4, ARL3, TMA16, RRS1 and YOX1 mRNAs to prevent their toxic accumulation during replication stress. Accumulation of YOX1 mRNA causes aberrant downregulation of a network of genes critical for DNA replication stress resistance and leads to toxic acetaldehyde accumulation. Our data reveal the scope and the targets of regulation by P-body proteins during the DNA replication stress response. P-bodies form in response to stress and act as sites of mRNA storage and degradation. Here the authors identify the mRNA targets of P-bodies during DNA replication stress, and show that P-body proteins act to prevent toxic accumulation of these target transcripts.
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Affiliation(s)
- Raphael Loll-Krippleber
- Department of Biochemistry and Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON, Canada, M5S 3E1
| | - Grant W Brown
- Department of Biochemistry and Donnelly Centre, University of Toronto, 160 College Street, Toronto, ON, Canada, M5S 3E1.
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13
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Pai CC, Kishkevich A, Deegan RS, Keszthelyi A, Folkes L, Kearsey SE, De León N, Soriano I, de Bruin RAM, Carr AM, Humphrey TC. Set2 Methyltransferase Facilitates DNA Replication and Promotes Genotoxic Stress Responses through MBF-Dependent Transcription. Cell Rep 2017; 20:2693-2705. [PMID: 28903048 PMCID: PMC5608972 DOI: 10.1016/j.celrep.2017.08.058] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Revised: 06/10/2017] [Accepted: 08/17/2017] [Indexed: 11/24/2022] Open
Abstract
Chromatin modification through histone H3 lysine 36 methylation by the SETD2 tumor suppressor plays a key role in maintaining genome stability. Here, we describe a role for Set2-dependent H3K36 methylation in facilitating DNA replication and the transcriptional responses to both replication stress and DNA damage through promoting MluI cell-cycle box (MCB) binding factor (MBF)-complex-dependent transcription in fission yeast. Set2 loss leads to reduced MBF-dependent ribonucleotide reductase (RNR) expression, reduced deoxyribonucleoside triphosphate (dNTP) synthesis, altered replication origin firing, and a checkpoint-dependent S-phase delay. Accordingly, prolonged S phase in the absence of Set2 is suppressed by increasing dNTP synthesis. Furthermore, H3K36 is di- and tri-methylated at these MBF gene promoters, and Set2 loss leads to reduced MBF binding and transcription in response to genotoxic stress. Together, these findings provide new insights into how H3K36 methylation facilitates DNA replication and promotes genotoxic stress responses in fission yeast.
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Affiliation(s)
- Chen-Chun Pai
- CRUK-MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK.
| | - Anastasiya Kishkevich
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6B, UK
| | - Rachel S Deegan
- CRUK-MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Andrea Keszthelyi
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, Sussex BN1 9RQ, UK
| | - Lisa Folkes
- CRUK-MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Stephen E Kearsey
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - Nagore De León
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - Ignacio Soriano
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | | | - Antony M Carr
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, Sussex BN1 9RQ, UK
| | - Timothy C Humphrey
- CRUK-MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK.
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14
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Boronat S, Domènech A, Carmona M, García-Santamarina S, Bañó MC, Ayté J, Hidalgo E. Lack of a peroxiredoxin suppresses the lethality of cells devoid of electron donors by channelling electrons to oxidized ribonucleotide reductase. PLoS Genet 2017. [PMID: 28640807 PMCID: PMC5501661 DOI: 10.1371/journal.pgen.1006858] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The thioredoxin and glutaredoxin pathways are responsible of recycling several enzymes which undergo intramolecular disulfide bond formation as part of their catalytic cycles such as the peroxide scavengers peroxiredoxins or the enzyme ribonucleotide reductase (RNR). RNR, the rate-limiting enzyme of deoxyribonucleotide synthesis, is an essential enzyme relying on these electron flow cascades for recycling. RNR is tightly regulated in a cell cycle-dependent manner at different levels, but little is known about the participation of electron donors in such regulation. Here, we show that cytosolic thioredoxins Trx1 and Trx3 are the primary electron donors for RNR in fission yeast. Unexpectedly, trx1 transcript and Trx1 protein levels are up-regulated in a G1-to-S phase-dependent manner, indicating that the supply of electron donors is also cell cycle-regulated. Indeed, genetic depletion of thioredoxins triggers a DNA replication checkpoint ruled by Rad3 and Cds1, with the final goal of up-regulating transcription of S phase genes and constitutive RNR synthesis. Regarding the thioredoxin and glutaredoxin cascades, one combination of gene deletions is synthetic lethal in fission yeast: cells lacking both thioredoxin reductase and cytosolic dithiol glutaredoxin. We have isolated a suppressor of this lethal phenotype: a mutation at the Tpx1-coding gene, leading to a frame shift and a loss-of-function of Tpx1, the main client of electron donors. We propose that in a mutant strain compromised in reducing equivalents, the absence of an abundant and competitive substrate such as the peroxiredoxin Tpx1 has been selected as a lethality suppressor to favor RNR function at the expense of the non-essential peroxide scavenging function, to allow DNA synthesis and cell growth. The essential enzyme ribonucleotide reductase (RNR), the rate-limiting enzyme of deoxyribonucleotide synthesis, relies on the thioredoxin and glutaredoxin electron flow cascades for recycling. RNR is tightly regulated in a cell cycle-dependent manner at different levels. Here, we show that cytosolic thioredoxin Trx1 is the primary electron donor for RNR in fission yeast, and that trx1 transcript and protein levels are up-regulated at G1-to-S phase transition. Genetic depletion of thioredoxins triggers the DNA replication checkpoint up-regulating RNR synthesis. Furthermore, deletion of the genes coding for thioredoxin reductase and dithiol glutaredoxin is synthetic lethal, and we show that a loss-of-function mutation at the peroxiredoxin Tpx1-coding gene acts as a genetic suppressor. We propose that in a mutant strain compromised in reducing equivalents, the absence of an abundant and competitive substrate of redoxins, the peroxiredoxin Tpx1, has been selected as a lethality suppressor to favor channeling of electrons to the essential RNR.
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Affiliation(s)
- Susanna Boronat
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - Alba Domènech
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - Mercè Carmona
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | | | - M. Carmen Bañó
- Departamento de Bioquímica y Biología Molecular, Universitat de València, Valencia, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
- * E-mail: (EH); (JA)
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
- * E-mail: (EH); (JA)
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15
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Herlihy AE, de Bruin RAM. The Role of the Transcriptional Response to DNA Replication Stress. Genes (Basel) 2017; 8:E92. [PMID: 28257104 PMCID: PMC5368696 DOI: 10.3390/genes8030092] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 02/20/2017] [Accepted: 02/23/2017] [Indexed: 01/14/2023] Open
Abstract
During DNA replication many factors can result in DNA replication stress. The DNA replication stress checkpoint prevents the accumulation of replication stress-induced DNA damage and the potential ensuing genome instability. A critical role for post-translational modifications, such as phosphorylation, in the replication stress checkpoint response has been well established. However, recent work has revealed an important role for transcription in the cellular response to DNA replication stress. In this review, we will provide an overview of current knowledge of the cellular response to DNA replication stress with a specific focus on the DNA replication stress checkpoint transcriptional response and its role in the prevention of replication stress-induced DNA damage.
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Affiliation(s)
- Anna E Herlihy
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK.
| | - Robertus A M de Bruin
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK.
- The UCL Cancer Institute, University College London, London WC1E 6BT, UK.
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16
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Gaspa L, González-Medina A, Hidalgo E, Ayté J. A functional genome-wide genetic screening identifies new pathways controlling the G1/S transcriptional wave. Cell Cycle 2016; 15:720-9. [PMID: 26890608 DOI: 10.1080/15384101.2016.1148839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
The Schizosaccharomyces pombe MBF complex activates the transcription of genes required for DNA synthesis and S phase. The MBF complex contains several proteins, including the core components Cdc10, Res1 and Res2, the co-repressor proteins Yox1 and Nrm1 and the co-activator Rep2. It has recently been shown how MBF is regulated when either the DNA damage or the DNA synthesis checkpoints are activated. However, how MBF is regulated in a normal unperturbed cell cycle is still not well understood. We have set up a genome-wide genomic screen searching for global regulators of MBF. We have crossed our knock-out collection library with a reporter strain that allows the measurement of MBF activity in live cells by flow cytometry. We confirm previously known regulators of MBF and show that COP9/signalosome and tRNA methyltransferases also regulate MBF activity.
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Affiliation(s)
- Laura Gaspa
- a Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra , Barcelona , Spain
| | | | - Elena Hidalgo
- a Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra , Barcelona , Spain
| | - José Ayté
- a Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra , Barcelona , Spain
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17
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Eckert D, Andrée N, Razanau A, Zock-Emmenthal S, Lützelberger M, Plath S, Schmidt H, Guerra-Moreno A, Cozzuto L, Ayté J, Käufer NF. Prp4 Kinase Grants the License to Splice: Control of Weak Splice Sites during Spliceosome Activation. PLoS Genet 2016; 12:e1005768. [PMID: 26730850 PMCID: PMC4701394 DOI: 10.1371/journal.pgen.1005768] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 12/03/2015] [Indexed: 12/02/2022] Open
Abstract
The genome of the fission yeast Schizosaccharomyces pombe encodes 17 kinases that are essential for cell growth. These include the cell-cycle regulator Cdc2, as well as several kinases that coordinate cell growth, polarity, and morphogenesis during the cell cycle. In this study, we further characterized another of these essential kinases, Prp4, and showed that the splicing of many introns is dependent on Prp4 kinase activity. For detailed characterization, we chose the genes res1 and ppk8, each of which contains one intron of typical size and position. Splicing of the res1 intron was dependent on Prp4 kinase activity, whereas splicing of the ppk8 intron was not. Extensive mutational analyses of the 5’ splice site of both genes revealed that proper transient interaction with the 5’ end of snRNA U1 governs the dependence of splicing on Prp4 kinase activity. Proper transient interaction between the branch sequence and snRNA U2 was also important. Therefore, the Prp4 kinase is required for recognition and efficient splicing of introns displaying weak exon1/5’ splice sites and weak branch sequences. Prp4 is an essential protein kinase that is involved in the splicing of some introns. Using a conditional mutant of Prp4, we showed that a subset of genes, including several cell cycle–regulatory genes, are dependent on Prp4 for splicing. Furthermore, we could convert genes between Prp4-dependent and -independent states by introducing single-nucleotide mutations in the exon1/5’ splice sites and branch sequence of introns. This work shows that Prp4 activity is required for splicing surveillance in a subset of mRNAs.
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Affiliation(s)
- Daniela Eckert
- Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Nicole Andrée
- Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Aleh Razanau
- Department of Physiology and Pathophysiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
| | | | - Martin Lützelberger
- Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Susann Plath
- Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Henning Schmidt
- Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Angel Guerra-Moreno
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
| | - Luca Cozzuto
- CRG Bioinformatics Core, Centre de Regulació Genòmica (CRG), and Universitat Pompeu Fabra, Barcelona, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona, Spain
- * E-mail: (JA); (NFK)
| | - Norbert F. Käufer
- Institute of Genetics, Technische Universität Braunschweig, Braunschweig, Germany
- * E-mail: (JA); (NFK)
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18
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Sartagul W, Zhou X, Yamada Y, Ma N, Tanaka K, Furuyashiki T, Ma Y. The MluI cell cycle box (MCB) motifs, but not damage-responsive elements (DREs), are responsible for the transcriptional induction of the rhp51+ gene in response to DNA replication stress. PLoS One 2014; 9:e111936. [PMID: 25372384 PMCID: PMC4221157 DOI: 10.1371/journal.pone.0111936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 09/23/2014] [Indexed: 01/09/2023] Open
Abstract
DNA replication stress induces the transcriptional activation of rhp51+, a fission yeast recA homolog required for repair of DNA double strand breaks. However, the mechanism by which DNA replication stress activates rhp51+ transcription is not understood. The promoter region of rhp51+ contains two damage-responsive elements (DREs) and two MluI cell cycle box (MCB) motifs. Using luciferase reporter assays, we examined the role of these elements in rhp51+ transcription. The full-length rhp51+ promoter and a promoter fragment containing MCB motifs only, but not a fragment containing DREs, mediated transcriptional activation upon DNA replication stress. Removal of the MCB motifs from the rhp51+ promoter abolished the induction of rhp51+ transcription by DNA replication stress. Consistent with a role for MCB motifs in rhp51+ transcription activation, deletion of the MBF (MCB-binding factor) co-repressors Nrm1 and Yox1 precluded rhp51+ transcriptional induction in response to DNA replication stress. Using cells deficient in checkpoint signaling molecules, we found that the Rad3-Cds1/Chk1 pathway partially mediated rhp51+ transcription in response to DNA replication stress, suggesting the involvement of unidentified checkpoint signaling pathways. Because MBF is critical for G1/S transcription, we examined how the cell cycle affected rhp51+ transcription. The transcription of rhp51+ and cdc18+, an MBF-dependent G1/S gene, peaked simultaneously in synchronized cdc25-22 cells. Furthermore, DNA replication stress maintained transcription of rhp51+ similarly to cdc18+. Collectively, these results suggest that MBF and its regulators mediate rhp51+ transcription in response to DNA replication stress, and underlie rhp51+ transcription at the G1/S transition.
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Affiliation(s)
- Wugangerile Sartagul
- Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Xin Zhou
- Department of Oncology, First Affiliated Hospital of Liaoning Medical University, Jinzhou, China
- Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan
- * E-mail: (XZ); (YM)
| | - Yuki Yamada
- Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Ning Ma
- Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Katsunori Tanaka
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Japan
| | - Tomoyuki Furuyashiki
- Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yan Ma
- Division of Pharmacology, Kobe University Graduate School of Medicine, Kobe, Japan
- * E-mail: (XZ); (YM)
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19
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Abstract
Nearly 20% of the budding yeast genome is transcribed periodically during the cell division cycle. The precise temporal execution of this large transcriptional program is controlled by a large interacting network of transcriptional regulators, kinases, and ubiquitin ligases. Historically, this network has been viewed as a collection of four coregulated gene clusters that are associated with each phase of the cell cycle. Although the broad outlines of these gene clusters were described nearly 20 years ago, new technologies have enabled major advances in our understanding of the genes comprising those clusters, their regulation, and the complex regulatory interplay between clusters. More recently, advances are being made in understanding the roles of chromatin in the control of the transcriptional program. We are also beginning to discover important regulatory interactions between the cell-cycle transcriptional program and other cell-cycle regulatory mechanisms such as checkpoints and metabolic networks. Here we review recent advances and contemporary models of the transcriptional network and consider these models in the context of eukaryotic cell-cycle controls.
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20
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Guarino E, Salguero I, Kearsey SE. Cellular regulation of ribonucleotide reductase in eukaryotes. Semin Cell Dev Biol 2014; 30:97-103. [PMID: 24704278 DOI: 10.1016/j.semcdb.2014.03.030] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 03/26/2014] [Indexed: 12/22/2022]
Abstract
Synthesis of deoxynucleoside triphosphates (dNTPs) is essential for both DNA replication and repair and a key step in this process is catalyzed by ribonucleotide reductases (RNRs), which reduce ribonucleotides (rNDPs) to their deoxy forms. Tight regulation of RNR is crucial for maintaining the correct levels of all four dNTPs, which is important for minimizing the mutation rate and avoiding genome instability. Although allosteric control of RNR was the first discovered mechanism involved in regulation of the enzyme, other controls have emerged in recent years. These include regulation of expression of RNR genes, proteolysis of RNR subunits, control of the cellular localization of the small RNR subunit, and regulation of RNR activity by small protein inhibitors. This review will focus on these additional mechanisms of control responsible for providing a balanced supply of dNTPs.
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Affiliation(s)
- Estrella Guarino
- Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.
| | - Israel Salguero
- Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.
| | - Stephen E Kearsey
- Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.
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21
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Control of cell cycle transcription during G1 and S phases. Nat Rev Mol Cell Biol 2013; 14:518-28. [PMID: 23877564 DOI: 10.1038/nrm3629] [Citation(s) in RCA: 964] [Impact Index Per Article: 87.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The accurate transition from G1 phase of the cell cycle to S phase is crucial for the control of eukaryotic cell proliferation, and its misregulation promotes oncogenesis. During G1 phase, growth-dependent cyclin-dependent kinase (CDK) activity promotes DNA replication and initiates G1-to-S phase transition. CDK activation initiates a positive feedback loop that further increases CDK activity, and this commits the cell to division by inducing genome-wide transcriptional changes. G1-S transcripts encode proteins that regulate downstream cell cycle events. Recent work is beginning to reveal the complex molecular mechanisms that control the temporal order of transcriptional activation and inactivation, determine distinct functional subgroups of genes and link cell cycle-dependent transcription to DNA replication stress in yeast and mammals.
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22
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Ivanova T, Alves-Rodrigues I, Gómez-Escoda B, Dutta C, DeCaprio JA, Rhind N, Hidalgo E, Ayté J. The DNA damage and the DNA replication checkpoints converge at the MBF transcription factor. Mol Biol Cell 2013; 24:3350-7. [PMID: 24006488 PMCID: PMC3814153 DOI: 10.1091/mbc.e13-05-0257] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
DNA damage and DNA replication checkpoints regulate differently the G1-to-S phase transcriptional program, resulting in the repression or induction, respectively, of the same set of genes. When this signaling is disrupted, cells are unable to cope with DNA-damaging agents, leading to increased cell lethality. In fission yeast cells, Cds1 is the effector kinase of the DNA replication checkpoint. We previously showed that when the DNA replication checkpoint is activated, the repressor Yox1 is phosphorylated and inactivated by Cds1, resulting in activation of MluI-binding factor (MBF)–dependent transcription. This is essential to reinitiate DNA synthesis and for correct G1-to-S transition. Here we show that Cdc10, which is an essential part of the MBF core, is the target of the DNA damage checkpoint. When fission yeast cells are treated with DNA-damaging agents, Chk1 is activated and phosphorylates Cdc10 at its carboxy-terminal domain. This modification is responsible for the repression of MBF-dependent transcription through induced release of MBF from chromatin. This inactivation of MBF is important for survival of cells challenged with DNA-damaging agents. Thus Yox1 and Cdc10 couple normal cell cycle regulation in unperturbed conditions and the DNA replication and DNA damage checkpoints into a single transcriptional complex.
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Affiliation(s)
- Tsvetomira Ivanova
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, Barcelona 08003, Spain Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605 Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115
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23
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Chino A, Makanae K, Moriya H. Relationships between cell cycle regulator gene copy numbers and protein expression levels in Schizosaccharomyces pombe. PLoS One 2013; 8:e73319. [PMID: 24019917 PMCID: PMC3760898 DOI: 10.1371/journal.pone.0073319] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 07/18/2013] [Indexed: 12/02/2022] Open
Abstract
We previously determined the copy number limits of overexpression for cell division cycle (cdc) regulatory genes in the fission yeast Schizosaccharomyces pombe using the “genetic tug-of-war” (gTOW) method. In this study, we measured the levels of tandem affinity purification (TAP)-tagged target proteins when their copy numbers are increased in gTOW. Twenty analyzed genes showed roughly linear correlations between increased protein levels and gene copy numbers, which suggested a general lack of compensation for gene dosage in S. pombe. Cdc16 and Sid2 protein levels but not their mRNA levels were much lower than that expected by their copy numbers, which suggested the existence of a post-transcriptional down regulation of these genes. The cyclin Cig1 protein level and its mRNA level were much higher than that expected by its copy numbers, which suggested a positive feedback mechanism for its expression. A higher Cdc10 protein level and its mRNA level, probably due to cloning its gene into a plasmid, indicated that Cdc10 regulation was more robust than that previously predicted.
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Affiliation(s)
- Ayako Chino
- Graduate School of Science and Technology, Okayama University, Kita-ku, Okayama, Japan
- Research Core for Interdisciplinary Sciences, Okayama University, Kita-ku, Okayama, Japan
| | - Koji Makanae
- Research Core for Interdisciplinary Sciences, Okayama University, Kita-ku, Okayama, Japan
| | - Hisao Moriya
- Research Core for Interdisciplinary Sciences, Okayama University, Kita-ku, Okayama, Japan
- * E-mail:
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24
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Deciphering the transcriptional-regulatory network of flocculation in Schizosaccharomyces pombe. PLoS Genet 2012; 8:e1003104. [PMID: 23236291 PMCID: PMC3516552 DOI: 10.1371/journal.pgen.1003104] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 10/03/2012] [Indexed: 01/07/2023] Open
Abstract
In the fission yeast Schizosaccharomyces pombe, the transcriptional-regulatory network that governs flocculation remains poorly understood. Here, we systematically screened an array of transcription factor deletion and overexpression strains for flocculation and performed microarray expression profiling and ChIP-chip analysis to identify the flocculin target genes. We identified five transcription factors that displayed novel roles in the activation or inhibition of flocculation (Rfl1, Adn2, Adn3, Sre2, and Yox1), in addition to the previously-known Mbx2, Cbf11, and Cbf12 regulators. Overexpression of mbx2(+) and deletion of rfl1(+) resulted in strong flocculation and transcriptional upregulation of gsf2(+)/pfl1(+) and several other putative flocculin genes (pfl2(+)-pfl9(+)). Overexpression of the pfl(+) genes singly was sufficient to trigger flocculation, and enhanced flocculation was observed in several combinations of double pfl(+) overexpression. Among the pfl1(+) genes, only loss of gsf2(+) abrogated the flocculent phenotype of all the transcription factor mutants and prevented flocculation when cells were grown in inducing medium containing glycerol and ethanol as the carbon source, thereby indicating that Gsf2 is the dominant flocculin. In contrast, the mild flocculation of adn2(+) or adn3(+) overexpression was likely mediated by the transcriptional activation of cell wall-remodeling genes including gas2(+), psu1(+), and SPAC4H3.03c. We also discovered that Mbx2 and Cbf12 displayed transcriptional autoregulation, and Rfl1 repressed gsf2(+) expression in an inhibitory feed-forward loop involving mbx2(+). These results reveal that flocculation in S. pombe is regulated by a complex network of multiple transcription factors and target genes encoding flocculins and cell wall-remodeling enzymes. Moreover, comparisons between the flocculation transcriptional-regulatory networks of Saccharomyces cerevisiae and S. pombe indicate substantial rewiring of transcription factors and cis-regulatory sequences.
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25
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Kim JY, Kwon ES, Roe JH. A homeobox protein Phx1 regulates long-term survival and meiotic sporulation in Schizosaccharomyces pombe. BMC Microbiol 2012; 12:86. [PMID: 22646093 PMCID: PMC3438059 DOI: 10.1186/1471-2180-12-86] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 04/09/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In the fission yeast Schizosaccharomyces pombe, the phx1+ (pombe homeobox) gene was initially isolated as a multi-copy suppressor of lysine auxotrophy caused by depletion of copper/zinc-containing superoxide dismutase (CuZn-SOD). Overproduction of Phx1 increased the synthesis of homocitrate synthase, the first enzyme in lysine biosynthetic pathway, which is labile to oxidative stress. Phx1 has a well conserved DNA-binding domain called homeodomain at the N-terminal region and is predicted to be a transcription factor in S. pombe. However, its role has not been revealed in further detail. Here we examined its expression pattern and the phenotype of its null mutant to get clues on its function. RESULTS Fluorescence from the Phx1-GFP expressed from a chromosomal fusion gene demonstrated that it is localized primarily in the nucleus, and is distinctly visible during the stationary phase. When we replaced the N-terminal homeobox domain of Phx1 with the DNA binding domain of Pap1, a well-characterized transcription factor, the chimeric protein caused the elevation of transcripts from Pap1-dependent genes such as ctt1+ and trr1+, suggesting that Phx1 possesses transcriptional activating activity when bound to DNA. The amount of phx1+ transcripts sharply increased as cells entered the stationary phase and was maintained at high level throughout the stationary phase. Nutrient shift down to low nitrogen or carbon sources caused phx1+ induction during the exponential phase, suggesting that cells need Phx1 for maintenance function during nutrient starvation. The Δphx1 null mutant showed decreased viability in long-term culture, whereas overproduction of Phx1 increased viability. Decrease in long-term survival was also observed for Δphx1 under N- or C-starved conditions. In addition, Δphx1 mutant was more sensitive to various oxidants and heat shock. When we examined sporulation of the Δphx1/Δphx1 diploid strain, significant decrease in the formation of meiotic spores was observed. CONCLUSIONS Phx1 is a transcriptional regulator whose synthesis is elevated during stationary phase and by nutrient starvation in S. pombe. It supports long-term survival and stress tolerance against oxidation and heat, and plays a key role in the formation of meiotic spores.
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Affiliation(s)
- Ji-Yoon Kim
- Laboratory of Molecular Microbiology, School of Biological Sciences, and Institute of Microbiology, Seoul National University, Seoul, South Korea
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26
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Ribonucleotide reductase activity is coupled to DNA synthesis via proliferating cell nuclear antigen. Curr Biol 2012; 22:720-6. [PMID: 22464192 DOI: 10.1016/j.cub.2012.02.070] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 02/06/2012] [Accepted: 02/29/2012] [Indexed: 11/24/2022]
Abstract
Synthesis of deoxynucleoside triphosphates (dNTPs) is required for both DNA replication and DNA repair and is catalyzed by ribonucleotide reductases (RNR), which convert ribonucleotides to their deoxy forms [1, 2]. Maintaining the correct levels of dNTPs for DNA synthesis is important for minimizing the mutation rate [3-7], and this is achieved by tight regulation of RNR [2, 8, 9]. In fission yeast, RNR is regulated in part by a small protein inhibitor, Spd1, which is degraded in S phase and after DNA damage to allow upregulation of dNTP supply [10-12]. Spd1 degradation is mediated by the activity of the CRL4(Cdt2) ubiquitin ligase complex [5, 13, 14]. This has been reported to be dependent on modulation of Cdt2 levels, which are cell cycle regulated, peaking in S phase, and which also increase after DNA damage in a checkpoint-dependent manner [7, 13]. We show here that Cdt2 level fluctuations are not sufficient to regulate Spd1 proteolysis and that the key step in this event is the interaction of Spd1 with the polymerase processivity factor proliferating cell nuclear antigen (PCNA), complexed onto DNA. This mechanism thus provides a direct link between DNA synthesis and RNR regulation.
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27
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Bastos de Oliveira FM, Harris MR, Brazauskas P, de Bruin RAM, Smolka MB. Linking DNA replication checkpoint to MBF cell-cycle transcription reveals a distinct class of G1/S genes. EMBO J 2012; 31:1798-810. [PMID: 22333912 DOI: 10.1038/emboj.2012.27] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 01/20/2012] [Indexed: 12/16/2022] Open
Abstract
Reprogramming gene expression is crucial for DNA replication stress response. We used quantitative proteomics to establish how the transcriptional response results in changes in protein levels. We found that expression of G1/S cell-cycle targets are strongly up-regulated upon replication stress, and show that MBF, but not SBF genes, are up-regulated via Rad53-dependent inactivation of the MBF co-repressor Nrm1. A subset of G1/S genes was found to undergo an SBF-to-MBF switch at the G1/S transition, enabling replication stress-induced transcription of genes targeted by SBF during G1. This subset of G1/S genes is characterized by an overlapping Swi4/Mbp1-binding site and is enriched for genes that cause a cell cycle and/or growth defect when overexpressed. Analysis of the prototypical switch gene TOS4 (Target Of SBF 4) reveals its role as a checkpoint effector supporting the importance of this distinct class of G1/S genes for the DNA replication checkpoint response. Our results reveal that replication stress induces expression of G1/S genes via the Rad53-MBF pathway and that an SBF-to-MBF switch characterizes a new class of genes that can be induced by replication stress.
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Affiliation(s)
- Francisco M Bastos de Oliveira
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
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