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Otsubo Y, Yamashita A, Goto Y, Sakai K, Iida T, Yoshimura S, Johzuka K. Cellular responses to compound stress induced by atmospheric-pressure plasma in fission yeast. J Cell Sci 2023; 136:jcs261292. [PMID: 37990810 DOI: 10.1242/jcs.261292] [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: 04/28/2023] [Accepted: 11/13/2023] [Indexed: 11/23/2023] Open
Abstract
The stress response is one of the most fundamental cellular processes. Although the molecular mechanisms underlying responses to a single stressor have been extensively studied, cellular responses to multiple stresses remain largely unknown. Here, we characterized fission yeast cellular responses to a novel stress inducer, non-thermal atmospheric-pressure plasma. Plasma irradiation generates ultraviolet radiation, electromagnetic fields and a variety of chemically reactive species simultaneously, and thus can impose multiple stresses on cells. We applied direct plasma irradiation to fission yeast and showed that strong plasma irradiation inhibited fission yeast growth. We demonstrated that mutants lacking sep1 and ace2, both of which encode transcription factors required for proper cell separation, were resistant to plasma irradiation. Sep1-target transcripts were downregulated by mild plasma irradiation. We also demonstrated that plasma irradiation inhibited the target of rapamycin kinase complex 1 (TORC1). These observations indicate that two pathways, namely the Sep1-Ace2 cell separation pathway and TORC1 pathway, operate when fission yeast cope with multiple stresses induced by plasma irradiation.
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Affiliation(s)
- Yoko Otsubo
- Interdisciplinary Research Unit, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Akira Yamashita
- Interdisciplinary Research Unit, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
- Center for Low-temperature Plasma Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Yuhei Goto
- Quantitative Biology Research Group, Exploratory Research Center on Life and Living Systems (ExCELLS), 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- Division of Quantitative Biology, National Institute for Basic Biology, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Keiichiro Sakai
- Quantitative Biology Research Group, Exploratory Research Center on Life and Living Systems (ExCELLS), 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- Division of Quantitative Biology, National Institute for Basic Biology, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Tetsushi Iida
- Gene Engineering Division, RIKEN BioResource Research Center (BRC), 3-1-1 Koyadai, Tsukuba-shi, Ibaraki 305-0074, Japan
| | - Shinji Yoshimura
- Center for Low-temperature Plasma Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
- National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292, Japan
| | - Katsuki Johzuka
- Interdisciplinary Research Unit, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
- Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Nishigonaka 38, Myodaiji, Okazaki, Aichi 444-8585, Japan
- Astrobiology Center, National Institutes of Natural Sciences, Nishigonaka 38, Myodaiji, Aichi 444-8585, Japan
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Abstract
The centrosome is a multifunctional organelle that is known primarily for its microtubule organising function. Centrosomal defects caused by changes in centrosomal structure or number have been associated with human diseases ranging from congenital defects to cancer. We are only beginning to appreciate how the non-microtubule organising roles of the centrosome are related to these clinical conditions. In this review, we will discuss the historical evidence that led to the proposal that the centrosome participates in cell cycle regulation. We then summarize the body of work that describes the involvement of the mammalian centrosome in triggering cell cycle progression and checkpoint signalling. Then we will highlight work from the fission yeast model organism, revealing the molecular details that explain how the spindle pole body (SPB, the yeast functional equivalent of the centrosome), participates in these cell cycle transitions. Importantly, we will discuss some of the emerging questions from recent discoveries related to the role of the centrosome as a cell cycle regulator.
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Nambu M, Kishikawa A, Yamada T, Ichikawa K, Kira Y, Itabashi Y, Honda A, Yamada K, Murakami H, Yamamoto A. Direct evaluation of cohesin-mediated sister kinetochore associations at meiosis I in fission yeast. J Cell Sci 2022; 135:jcs259102. [PMID: 34851403 DOI: 10.1242/jcs.259102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 11/16/2021] [Indexed: 11/20/2022] Open
Abstract
Kinetochores drive chromosome segregation by mediating chromosome interactions with the spindle. In higher eukaryotes, sister kinetochores are separately positioned on opposite sides of sister centromeres during mitosis, but associate with each other during meiosis I. Kinetochore association facilitates the attachment of sister chromatids to the same pole, enabling the segregation of homologous chromosomes toward opposite poles. In the fission yeast, Schizosaccharomyces pombe, Rec8-containing meiotic cohesin is suggested to establish kinetochore associations by mediating cohesion of the centromere cores. However, cohesin-mediated kinetochore associations on intact chromosomes have never been demonstrated directly. In the present study, we describe a novel method for the direct evaluation of kinetochore associations on intact chromosomes in live S. pombe cells, and demonstrate that sister kinetochores and the centromere cores are positioned separately on mitotic chromosomes but associate with each other on meiosis I chromosomes. Furthermore, we demonstrate that kinetochore association depends on meiotic cohesin and the cohesin regulators Moa1 and Mrc1, and requires mating-pheromone signaling for its establishment. These results confirm cohesin-mediated kinetochore association and its regulatory mechanisms, along with the usefulness of the developed method for its analysis. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Masashi Nambu
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Atsuki Kishikawa
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Takatomi Yamada
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan
| | - Kento Ichikawa
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Yunosuke Kira
- Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Yuta Itabashi
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Akira Honda
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Kohei Yamada
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Hiroshi Murakami
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan
| | - Ayumu Yamamoto
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
- Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
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Morafraile EC, Bugallo A, Carreira R, Fernández M, Martín-Castellanos C, Blanco MG, Segurado M. Exo1 phosphorylation inhibits exonuclease activity and prevents fork collapse in rad53 mutants independently of the 14-3-3 proteins. Nucleic Acids Res 2020; 48:3053-3070. [PMID: 32020204 PMCID: PMC7102976 DOI: 10.1093/nar/gkaa054] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/15/2020] [Accepted: 01/20/2020] [Indexed: 01/04/2023] Open
Abstract
The S phase checkpoint is crucial to maintain genome stability under conditions that threaten DNA replication. One of its critical functions is to prevent Exo1-dependent fork degradation, and Exo1 is phosphorylated in response to different genotoxic agents. Exo1 seemed to be regulated by several post-translational modifications in the presence of replicative stress, but the specific contribution of checkpoint-dependent phosphorylation to Exo1 control and fork stability is not clear. We show here that Exo1 phosphorylation is Dun1-independent and Rad53-dependent in response to DNA damage or dNTP depletion, and in both situations Exo1 is similarly phosphorylated at multiple sites. To investigate the correlation between Exo1 phosphorylation and fork stability, we have generated phospho-mimic exo1 alleles that rescue fork collapse in rad53 mutants as efficiently as exo1-nuclease dead mutants or the absence of Exo1, arguing that Rad53-dependent phosphorylation is the mayor requirement to preserve fork stability. We have also shown that this rescue is Bmh1–2 independent, arguing that the 14-3-3 proteins are dispensable for fork stabilization, at least when Exo1 is downregulated. Importantly, our results indicated that phosphorylation specifically inhibits the 5' to 3'exo-nuclease activity, suggesting that this activity of Exo1 and not the flap-endonuclease, is the enzymatic activity responsible of the collapse of stalled replication forks in checkpoint mutants.
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Affiliation(s)
- Esther C Morafraile
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
| | - Alberto Bugallo
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
| | - Raquel Carreira
- Departamento de Bioquímica y Biología Molecular, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS) - Instituto de Investigación Sanitaria (IDIS), Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - María Fernández
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain
| | | | - Miguel G Blanco
- Departamento de Bioquímica y Biología Molecular, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas (CIMUS) - Instituto de Investigación Sanitaria (IDIS), Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Mónica Segurado
- Instituto de Biología Funcional y Genómica (CSIC/USAL), Campus Miguel de Unamuno, Salamanca 37007, Spain.,Departamento de Microbiología y Genética, Campus Miguel de Unamuno, Universidad de Salamanca, Salamanca 37007, Spain
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Cussiol JRR, Soares BL, Oliveira FMBD. From yeast to humans: Understanding the biology of DNA Damage Response (DDR) kinases. Genet Mol Biol 2019; 43:e20190071. [PMID: 31930279 PMCID: PMC7198005 DOI: 10.1590/1678-4685-gmb-2019-0071] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 07/19/2019] [Indexed: 12/20/2022] Open
Abstract
The DNA Damage Response (DDR) is a complex network of biological processes that protect cells from accumulating aberrant DNA structures, thereby maintaining genomic stability and, as a consequence, preventing the development of cancer and other diseases. The DDR pathway is coordinated by a signaling cascade mediated by the PI3K-like kinases (PIKK) ATM and ATR and by their downstream kinases CHK2 and CHK1, respectively. Together, these kinases regulate several aspects of the cellular program in response to genomic stress. Much of our understanding of these kinases came from studies performed in the 1990s using yeast as a model organism. The purpose of this review is to present a historical perspective on the discovery of the DDR kinases in yeast and the importance of this model for the identification and functional understanding of their mammalian orthologues.
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Affiliation(s)
| | - Bárbara Luísa Soares
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Choline-Based Ionic Liquids as Media for the Growth of Saccharomyces cerevisiae. Processes (Basel) 2019. [DOI: 10.3390/pr7070471] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Ionic liquids (ILs) have garnered great attention as alternative solvents in many biological reactions and applications. However, its unknown toxicity is in line with the challenges to use it for biological applications. In this study, three choline based Ionic Liquids—choline saccharinate (CS), choline dihydrogen phosphate (CDHP), and choline tryptophanate (CT) were assessed for their suitability on the growth of Saccharomyces cerevisiae. The ILs were incorporated into the growth media of S. cerevisiae (defined as synthetic media) to access its potential as a substitute to conventional media. The compatibility of the synthetic media was evaluated based on the toxicity (EC50), growth curve, and glucose profile. The results showed that the incorporation of CDHP and CS did promote the growth of S. cerevisiae with a rapid glucose consumption rate. The growth of S. cerevisiae with the media composition of yeast extract, peptone, and CS showed improvement of 13%. We believe that these observations have implications in the biocompatibility studies of ILs to microorganisms.
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Jin W, Zhou L, Yan B, Yan L, Liu F, Tong P, Yu W, Dong X, Xie L, Zhang J, Xu Y, Li C, Yuan Q, Shan L, Efferth T. Theabrownin triggers DNA damage to suppress human osteosarcoma U2OS cells by activating p53 signalling pathway. J Cell Mol Med 2018; 22:4423-4436. [PMID: 29993186 PMCID: PMC6111873 DOI: 10.1111/jcmm.13742] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 05/21/2018] [Indexed: 12/21/2022] Open
Abstract
Osteosarcoma becomes the second leading cause of cancer death in the younger population. Current outcomes of chemotherapy on osteosarcoma were unsatisfactory to date, demanding development of effective therapies. Tea is a commonly used beverage beneficial to human health. As a major component of tea, theabrownin has been reported to possess anti‐cancer activity. To evaluate its anti‐osteosarcoma effect, we established a xenograft model of zebrafish and employed U2OS cells for in vivo and in vitro assays. The animal data showed that TB significantly inhibited the tumour growth with stronger effect than that of chemotherapy. The cellular data confirmed that TB‐triggered DNA damage and induced apoptosis of U2OS cells by regulation of Mki67, PARP, caspase 3 and H2AX, and Western blot assay showed an activation of p53 signalling pathway. When P53 was knocked down by siRNA, the subsequent downstream signalling was blocked, indicating a p53‐dependent mechanism of TB on U2OS cells (p53 wt). Using osteosarcoma cell lines with p53 mutations (HOS, SAOS‐2 and MG63), we found that TB exerted stronger inhibitory effect on U2OS cells than that on p53‐mut cell lines, but it also exerted obvious effect on SAOS‐2 cells (p53 null), suggesting an activation of p53‐independent pathway in the p53‐null cells. Interestingly, theabrownin was found to have no toxicity on normal tissue in vivo and could even increase the viability of p53‐wt normal cells. In sum, theabrownin could trigger DNA damage and induce apoptosis on U2OS cells via a p53‐dependent mechanism, being a promising candidate for osteosarcoma therapy.
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Affiliation(s)
- Wangdong Jin
- The First Affiliated Hospital, Zhejiang Chinese Medical University, Hangzhou, China
| | - Li Zhou
- The First Affiliated Hospital, Zhejiang Chinese Medical University, Hangzhou, China
| | - Bo Yan
- The First Affiliated Hospital, Zhejiang Chinese Medical University, Hangzhou, China
| | - Li Yan
- The First Affiliated Hospital, Zhejiang Chinese Medical University, Hangzhou, China
| | - Fucun Liu
- Department of Orthopaedics, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Peijian Tong
- The First Affiliated Hospital, Zhejiang Chinese Medical University, Hangzhou, China
| | - Wenhua Yu
- Hangzhou First People's Hospital, Hangzhou, China
| | | | - Li Xie
- Analysis Center of Agrobiology and Environmental Science, Zhejiang University, Hangzhou, China
| | | | - Yiqiao Xu
- Hunter Biotechnology, Inc, Hangzhou, China
| | - Chunqi Li
- Hunter Biotechnology, Inc, Hangzhou, China
| | - Qiang Yuan
- The First Affiliated Hospital, Zhejiang Chinese Medical University, Hangzhou, China
| | - Letian Shan
- The First Affiliated Hospital, Zhejiang Chinese Medical University, Hangzhou, China
| | - Thomas Efferth
- Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Mainz, Germany
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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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Chan KY, Alonso-Nuñez M, Grallert A, Tanaka K, Connolly Y, Smith DL, Hagan IM. Dialogue between centrosomal entrance and exit scaffold pathways regulates mitotic commitment. J Cell Biol 2017; 216:2795-2812. [PMID: 28774892 PMCID: PMC5584178 DOI: 10.1083/jcb.201702172] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 06/20/2017] [Accepted: 06/28/2017] [Indexed: 11/22/2022] Open
Abstract
The fission yeast scaffold molecule Sid4 anchors the septum initiation network to the spindle pole body (SPB, centrosome equivalent) to control mitotic exit events. A second SPB-associated scaffold, Cut12, promotes SPB-associated Cdk1-cyclin B to drive mitotic commitment. Signals emanating from each scaffold have been assumed to operate independently to promote two distinct outcomes. We now find that signals from Sid4 contribute to the Cut12 mitotic commitment switch. Specifically, phosphorylation of Sid4 by NIMAFin1 reduces Sid4 affinity for its SPB anchor, Ppc89, while also enhancing Sid4's affinity for casein kinase 1δ (CK1δ). The resulting phosphorylation of Sid4 by the newly docked CK1δ recruits Chk2Cds1 to Sid4. Chk2Cds1 then expels the Cdk1-cyclin B antagonistic phosphatase Flp1/Clp1 from the SPB. Flp1/Clp1 departure can then support mitotic commitment when Cdk1-cyclin B activation at the SPB is compromised by reduction of Cut12 function. Such integration of signals emanating from neighboring scaffolds shows how centrosomes/SPBs can integrate inputs from multiple pathways to control cell fate.
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Affiliation(s)
- Kuan Yoow Chan
- Cell Division Group, Cancer Research UK Manchester Institute, University of Manchester, Manchester, England, UK
| | - Marisa Alonso-Nuñez
- Cell Division Group, Cancer Research UK Manchester Institute, University of Manchester, Manchester, England, UK
| | - Agnes Grallert
- Cell Division Group, Cancer Research UK Manchester Institute, University of Manchester, Manchester, England, UK
| | - Kayoko Tanaka
- Cell Division Group, Cancer Research UK Manchester Institute, University of Manchester, Manchester, England, UK
| | - Yvonne Connolly
- Biological Mass Spectrometry Facility, Cancer Research UK Manchester Institute, University of Manchester, Manchester, England, UK
| | - Duncan L Smith
- Biological Mass Spectrometry Facility, Cancer Research UK Manchester Institute, University of Manchester, Manchester, England, UK
| | - Iain M Hagan
- Cell Division Group, Cancer Research UK Manchester Institute, University of Manchester, Manchester, England, UK
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Escorcia W, Forsburg SL. Destabilization of the replication fork protection complex disrupts meiotic chromosome segregation. Mol Biol Cell 2017; 28:2978-2997. [PMID: 28855376 PMCID: PMC5662257 DOI: 10.1091/mbc.e17-02-0101] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 08/21/2017] [Accepted: 08/23/2017] [Indexed: 12/17/2022] Open
Abstract
The replication fork protection complex (FPC) coordinates multiple processes that are crucial for unimpeded passage of the replisome through various barriers and difficult to replicate areas of the genome. We examine the function of Swi1 and Swi3, fission yeast's primary FPC components, to elucidate how replication fork stability contributes to DNA integrity in meiosis. We report that destabilization of the FPC results in reduced spore viability, delayed replication, changes in recombination, and chromosome missegregation in meiosis I and meiosis II. These phenotypes are linked to accumulation and persistence of DNA damage markers in meiosis and to problems with cohesion stability at the centromere. These findings reveal an important connection between meiotic replication fork stability and chromosome segregation, two processes with major implications to human reproductive health.
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Affiliation(s)
- Wilber Escorcia
- Program in Molecular & Computational Biology, University of Southern California, Los Angeles, CA 90089-2910
| | - Susan L Forsburg
- Program in Molecular & Computational Biology, University of Southern California, Los Angeles, CA 90089-2910
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11
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Li W, Yi J, Agbu P, Zhou Z, Kelley RL, Kallgren S, Jia S, He X. Replication stress affects the fidelity of nucleosome-mediated epigenetic inheritance. PLoS Genet 2017; 13:e1006900. [PMID: 28749973 PMCID: PMC5549764 DOI: 10.1371/journal.pgen.1006900] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 08/08/2017] [Accepted: 06/29/2017] [Indexed: 02/06/2023] Open
Abstract
The fidelity of epigenetic inheritance or, the precision by which epigenetic information is passed along, is an essential parameter for measuring the effectiveness of the process. How the precision of the process is achieved or modulated, however, remains largely elusive. We have performed quantitative measurement of epigenetic fidelity, using position effect variegation (PEV) in Schizosaccharomyces pombe as readout, to explore whether replication perturbation affects nucleosome-mediated epigenetic inheritance. We show that replication stresses, due to either hydroxyurea treatment or various forms of genetic lesions of the replication machinery, reduce the inheritance accuracy of CENP-A/Cnp1 nucleosome positioning within centromere. Mechanistically, we demonstrate that excessive formation of single-stranded DNA, a common molecular abnormality under these conditions, might have correlation with the reduction in fidelity of centromeric chromatin duplication. Furthermore, we show that replication stress broadly changes chromatin structure at various loci in the genome, such as telomere heterochromatin expanding and mating type locus heterochromatin spreading out of the boundaries. Interestingly, the levels of inheritable expanding at sub-telomeric heterochromatin regions are highly variable among independent cell populations. Finally, we show that HU treatment of the multi-cellular organisms C. elegans and D. melanogaster affects epigenetically programmed development and PEV, illustrating the evolutionary conservation of the phenomenon. Replication stress, in addition to its demonstrated role in genetic instability, promotes variable epigenetic instability throughout the epigenome. In this study, we found replication stresses reduce the fidelity of nucleosome-mediated epigenetic inheritance. Using Position Effect Variegation (PEV) in centromere as an indicator of chromatin epigenetic stability, we quantified the precision of nucleosomal inheritance and found replication stresses reduce the fidelity of nucleosome-mediated epigenetic inheritance. Further analysis of genome-wide heterochromatin distribution showed that replication stresses affect chromatin structure by expanding of heterochromatin with locus specificity. Mechanistically, we provide evidence suggesting that excessive formation of single-stranded DNA might have correlation with the reduction in fidelity of centromeric chromatin duplication. Finally, we demonstrated replication stress perturb the development process by reducing the fidelity of chromatin organization duplication in fruit fly and worm, illustrating the broadness and the evolutionary conservation of the phenomenon. Together, our results shed light on the importance of replication stresses cause epigenetic instability in addition to genetic stability.
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Affiliation(s)
- Wenzhu Li
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jia Yi
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang, China
| | - Pamela Agbu
- Department of Biochemistry and Molecular Biology
| | - Zheng Zhou
- Department of Biochemistry and Molecular Biology
| | - Richard L. Kelley
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States of America
| | - Scott Kallgren
- Department of Biological Sciences, Columbia University, New York, NY, United States of America
| | - Songtao Jia
- Department of Biological Sciences, Columbia University, New York, NY, United States of America
| | - Xiangwei He
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang, China
- * E-mail:
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Glass LN, Swapna G, Chavadi SS, Tufariello JM, Mi K, Drumm JE, Lam TT, Zhu G, Zhan C, Vilchéze C, Arcos J, Chen Y, Bi L, Mehta S, Porcelli SA, Almo SC, Yeh SR, Jacobs WR, Torrelles JB, Chan J. Mycobacterium tuberculosis universal stress protein Rv2623 interacts with the putative ATP binding cassette (ABC) transporter Rv1747 to regulate mycobacterial growth. PLoS Pathog 2017; 13:e1006515. [PMID: 28753640 PMCID: PMC5549992 DOI: 10.1371/journal.ppat.1006515] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 08/09/2017] [Accepted: 07/06/2017] [Indexed: 12/25/2022] Open
Abstract
We have previously shown that the Mycobacterium tuberculosis universal stress protein Rv2623 regulates mycobacterial growth and may be required for the establishment of tuberculous persistence. Here, yeast two-hybrid and affinity chromatography experiments have demonstrated that Rv2623 interacts with one of the two forkhead-associated domains (FHA I) of Rv1747, a putative ATP-binding cassette transporter annotated to export lipooligosaccharides. FHA domains are signaling protein modules that mediate protein-protein interactions to modulate a wide variety of biological processes via binding to conserved phosphorylated threonine (pT)-containing oligopeptides of the interactors. Biochemical, immunochemical and mass spectrometric studies have shown that Rv2623 harbors pT and specifically identified threonine 237 as a phosphorylated residue. Relative to wild-type Rv2623 (Rv2623WT), a mutant protein in which T237 has been replaced with a non-phosphorylatable alanine (Rv2623T237A) exhibits decreased interaction with the Rv1747 FHA I domain and diminished growth-regulatory capacity. Interestingly, compared to WT bacilli, an M. tuberculosis Rv2623 null mutant (ΔRv2623) displays enhanced expression of phosphatidyl-myo-inositol mannosides (PIMs), while the ΔRv1747 mutant expresses decreased levels of PIMs. Animal studies have previously shown that ΔRv2623 is hypervirulent, while ΔRv1747 is growth-attenuated. Collectively, these data have provided evidence that Rv2623 interacts with Rv1747 to regulate mycobacterial growth; and this interaction is mediated via the recognition of the conserved Rv2623 pT237-containing FHA-binding motif by the Rv1747 FHA I domain. The divergent aberrant PIM profiles and the opposing in vivo growth phenotypes of ΔRv2623 and ΔRv1747, together with the annotated lipooligosaccharide exporter function of Rv1747, suggest that Rv2623 interacts with Rv1747 to modulate mycobacterial growth by negatively regulating the activity of Rv1747; and that Rv1747 might function as a transporter of PIMs. Because these glycolipids are major mycobacterial cell envelope components that can impact on the immune response, our findings raise the possibility that Rv2623 may regulate bacterial growth, virulence, and entry into persistence, at least in part, by modulating the levels of bacillary PIM expression, perhaps through negatively regulating the Rv1747-dependent export of the immunomodulatory PIMs to alter host-pathogen interaction, thereby influencing the fate of M. tuberculosis in vivo.
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Affiliation(s)
- Lisa N. Glass
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Ganduri Swapna
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Sivagami Sundaram Chavadi
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - JoAnn M. Tufariello
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Kaixia Mi
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Joshua E. Drumm
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - TuKiet T. Lam
- MS & Proteomics Resource of the W.M. Keck Biotechnology Resource Laboratory, Yale University School Medicine, New Haven, Connecticut, United States of America
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Guofeng Zhu
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Chenyang Zhan
- Department of Biochemistry, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Catherine Vilchéze
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Howard Hughes Medical Institute, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Jesus Arcos
- Department of Microbial Infection and Immunity, College of Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - Yong Chen
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Lijun Bi
- Department of Medicine, School of Stomatology and Medicine, Foshan University, Foshan, China
| | - Simren Mehta
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Steven A. Porcelli
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Steve C. Almo
- Department of Biochemistry, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Syun-Ru Yeh
- Departments of Physiology & Biophysics, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - William R. Jacobs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Howard Hughes Medical Institute, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
| | - Jordi B. Torrelles
- Department of Microbial Infection and Immunity, College of Medicine, The Ohio State University, Columbus, Ohio, United States of America
| | - John Chan
- Department of Medicine, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
- Department of Microbiology and Immunology, Albert Einstein College of Medicine & Montefiore Medical Center, Bronx, New York, United States of America
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Functional Crosstalk between the PP2A and SUMO Pathways Revealed by Analysis of STUbL Suppressor, razor 1-1. PLoS Genet 2016; 12:e1006165. [PMID: 27398807 PMCID: PMC4939958 DOI: 10.1371/journal.pgen.1006165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 06/11/2016] [Indexed: 12/04/2022] Open
Abstract
Posttranslational modifications (PTMs) provide dynamic regulation of the cellular proteome, which is critical for both normal cell growth and for orchestrating rapid responses to environmental stresses, e.g. genotoxins. Key PTMs include ubiquitin, the Small Ubiquitin-like MOdifier SUMO, and phosphorylation. Recently, SUMO-targeted ubiquitin ligases (STUbLs) were found to integrate signaling through the SUMO and ubiquitin pathways. In general, STUbLs are recruited to target proteins decorated with poly-SUMO chains to ubiquitinate them and drive either their extraction from protein complexes, and/or their degradation at the proteasome. In fission yeast, reducing or preventing the formation of SUMO chains can circumvent the essential and DNA damage response functions of STUbL. This result indicates that whilst some STUbL "targets" have been identified, the crucial function of STUbL is to antagonize SUMO chain formation. Herein, by screening for additional STUbL suppressors, we reveal crosstalk between the serine/threonine phosphatase PP2A-Pab1B55 and the SUMO pathway. A hypomorphic Pab1B55 mutant not only suppresses STUbL dysfunction, but also mitigates the phenotypes associated with deletion of the SUMO protease Ulp2, or mutation of the STUbL cofactor Rad60. Together, our results reveal a novel role for PP2A-Pab1B55 in modulating SUMO pathway output, acting in parallel to known critical regulators of SUMOylation homeostasis. Given the broad evolutionary functional conservation of the PP2A and SUMO pathways, our results could be relevant to the ongoing attempts to therapeutically target these factors. Posttranslational modifiers (PTMs) orchestrate the proteins and processes that control genome stability and cell growth. Accordingly, deregulation of PTMs causes disease, but can also be harnessed therapeutically. Crosstalk between PTMs is widespread, and acts to increase specificity and selectivity in signal transduction. Such crosstalk exists between two major PTMs, SUMO and ubiquitin, wherein a SUMO-targeted ubiquitin ligase (STUbL) can additionally mark SUMO-modified proteins with ubiquitin. Thereby, STUbL generates a hybrid SUMO-ubiquitin signal that is recognized by selective effectors, which can extract proteins from complexes and/or direct their degradation at the proteasome. STUbL function is critical to maintain genome stability, and it also mediates the therapeutic effects of arsenic trioxide in leukemia treatment. Therefore, a full appreciation of STUbL regulation and integration with other PTMs is warranted. Unexpectedly, we find that reduced activity of PP2A, a major cellular phosphatase, compensates for STUbL inactivation. Our results indicate that PP2A-regulated phosphorylation reduces the SUMO chain output of the SUMO pathway, thus reducing cellular dependency on STUbL and the functionally related factors Ulp2 and Rad60. Our data not only reveal a striking level of plasticity in signaling through certain PTMs, but also highlight potential "escape" mechanisms for SUMO pathway-based therapies.
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Xu YJ. Inner nuclear membrane protein Lem2 facilitates Rad3-mediated checkpoint signaling under replication stress induced by nucleotide depletion in fission yeast. Cell Signal 2016; 28:235-45. [PMID: 26746798 PMCID: PMC4753118 DOI: 10.1016/j.cellsig.2015.12.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Revised: 12/02/2015] [Accepted: 12/17/2015] [Indexed: 01/19/2023]
Abstract
DNA replication checkpoint is a highly conserved cellular signaling pathway critical for maintaining genome integrity in eukaryotes. It is activated when DNA replication is perturbed. In Schizosaccharomyces pombe, perturbed replication forks activate the sensor kinase Rad3 (ATR/Mec1), which works cooperatively with mediator Mrc1 and the 9-1-1 checkpoint clamp to phosphorylate the effector kinase Cds1 (CHK2/Rad53). Phosphorylation of Cds1 promotes autoactivation of the kinase. Activated Cds1 diffuses away from the forks and stimulates most of the checkpoint responses under replication stress. Although this signaling pathway has been well understood in fission yeast, how the signaling is initiated and thus regulated remains incompletely understood. Previous studies have shown that deletion of lem2(+) sensitizes cells to the inhibitor of ribonucleotide reductase, hydroxyurea. However, the underlying mechanism is still not well understood. This study shows that in the presence of hydroxyurea, Lem2 facilitates Rad3-mediated checkpoint signaling for Cds1 activation. Without Lem2, all known Rad3-dependent phosphorylations critical for replication checkpoint signaling are seriously compromised, which likely causes the aberrant mitosis and drug sensitivity observed in this mutant. Interestingly, the mutant is not very sensitive to DNA damage and the DNA damage checkpoint remains largely intact, suggesting that the main function of Lem2 is to facilitate checkpoint signaling in response to replication stress. Since Lem2 is an inner nuclear membrane protein, these results also suggest that the replication checkpoint may be spatially regulated inside the nucleus, a previously unknown mechanism.
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Affiliation(s)
- Yong-Jie Xu
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, 3640 Colonel Glenn Hwy., Dayton OH 45435, USA.
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Gadaleta MC, Das MM, Tanizawa H, Chang YT, Noma KI, Nakamura TM, Noguchi E. Swi1Timeless Prevents Repeat Instability at Fission Yeast Telomeres. PLoS Genet 2016; 12:e1005943. [PMID: 26990647 PMCID: PMC4798670 DOI: 10.1371/journal.pgen.1005943] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 02/25/2016] [Indexed: 01/09/2023] Open
Abstract
Genomic instability associated with DNA replication stress is linked to cancer and genetic pathologies in humans. If not properly regulated, replication stress, such as fork stalling and collapse, can be induced at natural replication impediments present throughout the genome. The fork protection complex (FPC) is thought to play a critical role in stabilizing stalled replication forks at several known replication barriers including eukaryotic rDNA genes and the fission yeast mating-type locus. However, little is known about the role of the FPC at other natural impediments including telomeres. Telomeres are considered to be difficult to replicate due to the presence of repetitive GT-rich sequences and telomere-binding proteins. However, the regulatory mechanism that ensures telomere replication is not fully understood. Here, we report the role of the fission yeast Swi1Timeless, a subunit of the FPC, in telomere replication. Loss of Swi1 causes telomere shortening in a telomerase-independent manner. Our epistasis analyses suggest that heterochromatin and telomere-binding proteins are not major impediments for telomere replication in the absence of Swi1. Instead, repetitive DNA sequences impair telomere integrity in swi1Δ mutant cells, leading to the loss of repeat DNA. In the absence of Swi1, telomere shortening is accompanied with an increased recruitment of Rad52 recombinase and more frequent amplification of telomere/subtelomeres, reminiscent of tumor cells that utilize the alternative lengthening of telomeres pathway (ALT) to maintain telomeres. These results suggest that Swi1 ensures telomere replication by suppressing recombination and repeat instability at telomeres. Our studies may also be relevant in understanding the potential role of Swi1Timeless in regulation of telomere stability in cancer cells. In every round of the cell cycle, cells must accurately replicate their full genetic information. This process is highly regulated, as defects during DNA replication cause genomic instability, leading to various genetic disorders including cancers. To thwart these problems, cells carry an array of complex mechanisms to deal with various obstacles found across the genome that can hamper DNA replication and cause DNA damage. Understanding how these mechanisms are regulated and orchestrated is of paramount importance in the field. In this report, we describe how Swi1, a Timeless-related protein in fission yeast, regulates efficient replication of telomeres, which are considered to be difficult to replicate due to the presence of repetitive DNA and telomere-binding proteins. We show that Swi1 prevents telomere damage and maintains telomere length by protecting integrity of telomeric repeats. Swi1-mediated telomere maintenance is independent of telomerase activity, and loss of Swi1 causes hyper-activation of recombination-based telomere maintenance, which generates heterogeneous telomeres. Similar telomerase-independent and recombination-dependent mechanism is utilized by approximately 15% of human cancers, linking telomere replication defects with cancer development. Thus, our study may be relevant in understanding the role of telomere replication defects in the development of cancers in humans.
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Affiliation(s)
- Mariana C. Gadaleta
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Mukund M. Das
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Hideki Tanizawa
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - Ya-Ting Chang
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Ken-ichi Noma
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - Toru M. Nakamura
- Department of Biochemistry and Molecular Genetics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Eishi Noguchi
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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16
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Hoffman CS, Wood V, Fantes PA. An Ancient Yeast for Young Geneticists: A Primer on the Schizosaccharomyces pombe Model System. Genetics 2015; 201:403-23. [PMID: 26447128 PMCID: PMC4596657 DOI: 10.1534/genetics.115.181503] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The fission yeast Schizosaccharomyces pombe is an important model organism for the study of eukaryotic molecular and cellular biology. Studies of S. pombe, together with studies of its distant cousin, Saccharomyces cerevisiae, have led to the discovery of genes involved in fundamental mechanisms of transcription, translation, DNA replication, cell cycle control, and signal transduction, to name but a few processes. However, since the divergence of the two species approximately 350 million years ago, S. pombe appears to have evolved less rapidly than S. cerevisiae so that it retains more characteristics of the common ancient yeast ancestor, causing it to share more features with metazoan cells. This Primer introduces S. pombe by describing the yeast itself, providing a brief description of the origins of fission yeast research, and illustrating some genetic and bioinformatics tools used to study protein function in fission yeast. In addition, a section on some key differences between S. pombe and S. cerevisiae is included for readers with some familiarity with budding yeast research but who may have an interest in developing research projects using S. pombe.
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Affiliation(s)
- Charles S Hoffman
- Biology Department, Boston College, Chestnut Hill, Massachusetts 02467
| | - Valerie Wood
- Cambridge Systems Biology Centre and Department of Biochemistry, University of Cambridge, CB2 1GA Cambridge, United Kingdom
| | - Peter A Fantes
- School of Biological Sciences, College of Science and Engineering, University of Edinburgh EH9 3JR Edinburgh, United Kingdom
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Khan S, Ahmed S. Role of swi7H4 mutant allele of DNA polymerase α in the DNA damage checkpoint response. PLoS One 2015; 10:e0124063. [PMID: 25822347 PMCID: PMC4378889 DOI: 10.1371/journal.pone.0124063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 03/07/2015] [Indexed: 01/01/2023] Open
Abstract
Besides being a mediator of initiation of DNA replication, DNA polymerase α plays a key role in chromosome maintenance. Swi7H4, a novel temperature sensitive mutant of DNA polymerase α was shown to be defective in transcriptional silencing at the mating type centromere and telomere loci. It is also required for the establishment of chromatin state that can recruit the components of the heterochromatin machinery at these regions. Recently the role of DNA polymerase α in the S-phase alkylation damage response in S. pombe has also been studied. Here we investigate whether defects generated by swi7H4, a mutant allele of DNA polymerase α can activate a checkpoint response. We show that swi7H4 exhibit conditional synthetic lethality with chk1 null mutant and the double mutant of swi7H4 with chk1 deletion aggravate the chromosome segregation defects. More importantly swi7H4 mutant cells delay the mitotic progression at non permissive temperature that is mediated by checkpoint protein kinase Chk1. In addition we show that, in the swi7H4 mutant background, cells accumulate DNA damage at non permissive temperature activating the checkpoint kinase protein Chk1. Further, we observed synthetic lethality between swi7H4 and a number of genes involved in DNA repair pathway at semi permissive temperature. We summarize that defects in swi7H4 mutant results in DNA damage that delay mitosis in a Chk1 dependent manner that also require the damage repair pathway for proper recovery.
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Affiliation(s)
- Saman Khan
- Molecular and Structural Biology Division, CSIR- Central Drug Research Institute, Jankipuram Extension, Lucknow, India
| | - Shakil Ahmed
- Molecular and Structural Biology Division, CSIR- Central Drug Research Institute, Jankipuram Extension, Lucknow, India
- * E-mail:
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18
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Muñoz S, Manjón E, García P, Sunnerhagen P, Sánchez Y. The checkpoint-dependent nuclear accumulation of Rho1p exchange factor Rgf1p is important for tolerance to chronic replication stress. Mol Biol Cell 2014; 25:1137-50. [PMID: 24478458 PMCID: PMC3967976 DOI: 10.1091/mbc.e13-11-0689] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Guanine nucleotide exchange factors control many aspects of cell morphogenesis by turning on Rho-GTPases. The fission yeast exchange factor Rgf1p (Rho gef1) specifically regulates Rho1p during polarized growth and localizes to cortical sites. Here we report that Rgf1p is relocalized to the cell nucleus during the stalled replication caused by hydroxyurea (HU). Import to the nucleus is mediated by a nuclear localization sequence at the N-terminus of Rgf1p, whereas release into the cytoplasm requires two leucine-rich nuclear export sequences at the C-terminus. Moreover, Rgf1p nuclear accumulation during replication arrest depends on the 14-3-3 chaperone Rad24p and the DNA replication checkpoint kinase Cds1p. Both proteins control the nuclear accumulation of Rgf1p by inhibition of its nuclear export. A mutant, Rgf1p-9A, that substitutes nine serine potential phosphorylation Cds1p sites for alanine fails to accumulate in the nucleus in response to replication stress, and this correlates with a severe defect in survival in the presence of HU. In conclusion, we propose that the regulation of Rgf1p could be part of the mechanism by which Cds1p and Rad24p promote survival in the presence of chronic replication stress. It will be of general interest to understand whether the same is true for homologues of Rgf1p in budding yeast and higher eukaryotes.
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Affiliation(s)
- Sofía Muñoz
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, CSIC/Universidad de Salamanca, 37008 Salamanca, Spain Department of Chemistry and Molecular Biology, Lundberg Laboratory, University of Gothenburg, S-405 30 Gothenburg, Sweden
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20
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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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21
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Chaudari A, Huberman JA. Identification of two telomere-proximal fission yeast DNA replication origins constrained by nearby cis-acting sequences to replicate in late S phase. F1000Res 2012; 1:58. [PMID: 24358832 PMCID: PMC3790605 DOI: 10.12688/f1000research.1-58.v1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/21/2012] [Indexed: 11/20/2022] Open
Abstract
Telomeres of the fission yeast, Schizosaccharomyces pombe, are known to replicate in late S phase, but the reasons for this late replication are not fully understood. We have identified two closely-spaced DNA replication origins, 5.5 to 8 kb upstream from the telomere itself. These are the most telomere-proximal of all the replication origins in the fission yeast genome. When located by themselves in circular plasmids, these origins fired in early S phase, but if flanking sequences closer to the telomere were included in the circular plasmid, then replication was restrained to late S phase - except in cells lacking the replication-checkpoint kinase, Cds1. We conclude that checkpoint-dependent late replication of telomere-associated sequences is dependent on nearby cis-acting sequences, not on proximity to the physical end of a linear chromosome.
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Affiliation(s)
- Amna Chaudari
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, NY, 14263, USA
| | - Joel A Huberman
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, NY, 14263, USA
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22
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Sabatinos SA, Green MD, Forsburg SL. Continued DNA synthesis in replication checkpoint mutants leads to fork collapse. Mol Cell Biol 2012; 32:4986-97. [PMID: 23045396 PMCID: PMC3510540 DOI: 10.1128/mcb.01060-12] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 10/01/2012] [Indexed: 01/06/2023] Open
Abstract
Hydroxyurea (HU) treatment activates the intra-S phase checkpoint proteins Cds1 and Mrc1 to prevent replication fork collapse. We found that prolonged DNA synthesis occurs in cds1Δ and mrc1Δ checkpoint mutants in the presence of HU and continues after release. This is coincident with increased DNA damage measured by phosphorylated histone H2A in whole cells during release. High-resolution live-cell imaging shows that mutants first accumulate extensive replication protein A (RPA) foci, followed by increased Rad52. Both DNA synthesis and RPA accumulation require the MCM helicase. We propose that a replication fork "collapse point" in HU-treated cells describes the point at which accumulated DNA damage and instability at individual forks prevent further replication. After this point, cds1Δ and mrc1Δ forks cannot complete genome replication. These observations establish replication fork collapse as a dynamic process that continues after release from HU block.
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Affiliation(s)
- Sarah A Sabatinos
- Molecular and Computational Biology, University of Southern California, Los Angeles, California, USA.
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Abstract
The eukaryotic cell replicates its chromosomal DNA with almost absolute fidelity in the course of every cell cycle. This accomplishment is remarkable considering that the conditions for DNA replication are rarely ideal. The replication machinery encounters a variety of obstacles on the chromosome, including damaged template DNA. In addition, a number of chromosome regions are considered to be difficult to replicate owing to DNA secondary structures and DNA binding proteins required for various transactions on the chromosome. Under these conditions, replication forks stall or break, posing grave threats to genomic integrity. How does the cell combat such stressful conditions during DNA replication? The replication fork protection complex (FPC) may help answer this question. Recent studies have demonstrated that the FPC is required for the smooth passage of replication forks at difficult-to-replicate genomic regions and plays a critical role in coordinating multiple genome maintenance processes at the replication fork.
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Affiliation(s)
- Adam R. Leman
- Department of Biochemistry and Molecular Biology; Drexel University College of Medicine; Philadelphia, PA USA
| | - Eishi Noguchi
- Department of Biochemistry and Molecular Biology; Drexel University College of Medicine; Philadelphia, PA USA
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Furuya K, Niki H. Hyphal differentiation induced via a DNA damage checkpoint-dependent pathway engaged in crosstalk with nutrient stress signaling in Schizosaccharomyces japonicus. Curr Genet 2012; 58:291-303. [PMID: 23090706 PMCID: PMC3490063 DOI: 10.1007/s00294-012-0384-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 09/13/2012] [Accepted: 10/05/2012] [Indexed: 12/16/2022]
Abstract
DNA damage response includes DNA repair, nucleotide metabolism and even a control of cell fates including differentiation, cell death pathway or some combination of these. The responses to DNA damage differ from species to species. Here we aim to delineate the checkpoint pathway in the dimorphic fission yeast Schizosaccharomyces japonicus, where DNA damage can trigger a differentiation pathway that is a switch from a bidirectional yeast growth mode to an apical hyphal growth mode, and the switching is regulated via a checkpoint kinase, Chk1. This Chk1-dependent switch to hyphal growth is activated with even low doses of agents that damage DNA; therefore, we reasoned that this switch may depend on other genes orthologous to the components of the classical Sz. pombe Chk1-dependent DNA checkpoint pathway. As an initial test of this hypothesis, we assessed the effects of mutations in Sz. japonicus orthologs of Sz. pombe checkpoint genes on this switch from bidirectional to hyphal growth. The same set of DNA checkpoint genes was confirmed in Sz. japonicus. We tested the effect of each DNA checkpoint mutants on hyphal differentiation by DNA damage. We found that the Sz. japonicus hyphal differentiation pathway was dependent on Sz. japonicus orthologs of Sz. pombe checkpoint genes-(SP)rad3, (SP)rad26, (SP)rad9, (SP)rad1, (SP)rad24, (SP)rad25, (SP)crb2, and (SP)chk1-that function in the DNA damage checkpoint pathway, but was not dependent on orthologs of two Sz. pombe genes-(SP)cds1 or (SP)mrc1-that function in the DNA replication checkpoint pathway. These findings indicated that although the role of each component of the DNA damage checkpoint and DNA replication checkpoint is mostly same between the two fission yeasts, the DNA damage checkpoint was the only pathway that governed DNA damage-dependent hyphal growth. We also examined whether DNA damage checkpoint signaling engaged in functional crosstalk with other hyphal differentiation pathways because hyphal differentiation can also be triggered by nutritional stress. Here, we discovered genetic interactions that indicated that the cAMP pathway engaged in crosstalk with Chk1-dependent signaling.
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Affiliation(s)
- Kanji Furuya
- Department of Genetics, Graduate University for Advanced Studies, Sokendai, Hayama, Miura District, Japan
- Microbial Genetics Laboratory, Genetic Strains Research Center, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540 Japan
- Present Address: Department of Mutagenesis, Radiation Biology Center, Kyoto University, Kyoto, Japan
| | - Hironori Niki
- Department of Genetics, Graduate University for Advanced Studies, Sokendai, Hayama, Miura District, Japan
- Microbial Genetics Laboratory, Genetic Strains Research Center, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540 Japan
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Koulintchenko M, Vengrova S, Eydmann T, Arumugam P, Dalgaard JZ. DNA polymerase α (swi7) and the flap endonuclease Fen1 (rad2) act together in the S-phase alkylation damage response in S. pombe. PLoS One 2012; 7:e47091. [PMID: 23071723 PMCID: PMC3469492 DOI: 10.1371/journal.pone.0047091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 09/07/2012] [Indexed: 11/30/2022] Open
Abstract
Polymerase α is an essential enzyme mainly mediating Okazaki fragment synthesis during lagging strand replication. A specific point mutation in Schizosaccharomyces pombe polymerase α named swi7-1, abolishes imprinting required for mating-type switching. Here we investigate whether this mutation confers any genome-wide defects. We show that the swi7-1 mutation renders cells hypersensitive to the DNA damaging agents methyl methansulfonate (MMS), hydroxyurea (HU) and UV and incapacitates activation of the intra-S checkpoint in response to DNA damage. In addition we show that, in the swi7-1 background, cells are characterized by an elevated level of repair foci and recombination, indicative of increased genetic instability. Furthermore, we detect novel Swi1-, -Swi3- and Pol α- dependent alkylation damage repair intermediates with mobility on 2D-gel that suggests presence of single-stranded regions. Genetic interaction studies showed that the flap endonuclease Fen1 works in the same pathway as Pol α in terms of alkylation damage response. Fen1 was also required for formation of alkylation- damage specific repair intermediates. We propose a model to explain how Pol α, Swi1, Swi3 and Fen1 might act together to detect and repair alkylation damage during S-phase.
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Affiliation(s)
- Milana Koulintchenko
- Division of Biomedical Cell Biology, Warwick Medical School, Gibbet Hill Campus, University of Warwick, Coventry, United Kingdom
| | - Sonya Vengrova
- Division of Biomedical Cell Biology, Warwick Medical School, Gibbet Hill Campus, University of Warwick, Coventry, United Kingdom
| | - Trevor Eydmann
- Division of Biomedical Cell Biology, Warwick Medical School, Gibbet Hill Campus, University of Warwick, Coventry, United Kingdom
| | - Prakash Arumugam
- School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry, United Kingdom
| | - Jacob Z. Dalgaard
- Division of Biomedical Cell Biology, Warwick Medical School, Gibbet Hill Campus, University of Warwick, Coventry, United Kingdom
- * E-mail:
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26
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Sato H, Masuda F, Takayama Y, Takahashi K, Saitoh S. Epigenetic inactivation and subsequent heterochromatinization of a centromere stabilize dicentric chromosomes. Curr Biol 2012; 22:658-67. [PMID: 22464190 DOI: 10.1016/j.cub.2012.02.062] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 01/24/2012] [Accepted: 02/21/2012] [Indexed: 11/29/2022]
Abstract
BACKGROUND The kinetochore is a multiprotein complex that forms on a chromosomal locus designated as the centromere, which links the chromosome to the spindle during mitosis and meiosis. Most eukaryotes, with the exception of holocentric species, have a single distinct centromere per chromosome, and the presence of multiple centromeres on a single chromosome is predicted to cause breakage and/or loss of that chromosome. However, some stably maintained non-Robertsonian translocated chromosomes have been reported, suggesting that the excessive centromeres are inactivated by an as yet undetermined mechanism. RESULTS We have developed systems to generate dicentric chromosomes containing two centromeres by fusing two chromosomes in fission yeast. Although the majority of cells harboring the artificial dicentric chromosome are arrested with elongated cell morphology in a manner dependent on the DNA structure checkpoint genes, a portion of the cells survive by converting the dicentric chromosome into a stable functional monocentric chromosome; either centromere was inactivated epigenetically or by DNA rearrangement. Mutations compromising kinetochore formation increased the frequency of epigenetic centromere inactivation. The inactivated centromere is occupied by heterochromatin and frequently reactivated in heterochromatin- or histone deacetylase-deficient mutants. CONCLUSIONS Chromosomes with multiple centromeres are stabilized by epigenetic centromere inactivation, which is initiated by kinetochore disassembly. Consequent heterochromatinization and histone deacetylation expanding from pericentric repeats to the central domain prevent reactivation of the inactivated centromere.
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Affiliation(s)
- Hiroshi Sato
- Division of Cell Biology, Institute of Life Science, Kurume University, Hyakunen-kohen 1-1, Kurume, Fukuoka 839-0864, Japan.
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27
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Caetano C, Klier S, de Bruin RAM. Phosphorylation of the MBF repressor Yox1p by the DNA replication checkpoint keeps the G1/S cell-cycle transcriptional program active. PLoS One 2011; 6:e17211. [PMID: 21359180 PMCID: PMC3040222 DOI: 10.1371/journal.pone.0017211] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 01/25/2011] [Indexed: 11/19/2022] Open
Abstract
Background In fission yeast Schizosaccharomyces pombe G1/S cell-cycle regulated transcription depends upon MBF. A negative feedback loop involving Nrm1p and Yox1p bound to MBF leads to transcriptional repression as cells exit G1 phase. However, activation of the DNA replication checkpoint response during S phase results in persistent expression of MBF-dependent genes. Methodology/Principal Findings This report shows that Yox1p binding to MBF is Nrm1-dependent and that Yox1p and Nrm1p require each other to bind and repress MBF targets. In response to DNA replication stress both Yox1p and Nrm1p dissociate from MBF at promoters leading to de-repression of MBF targets. Inactivation of Yox1p is an essential part of the checkpoint response. Cds1p (human Chk2p) checkpoint protein kinase-dependent phosphorylation of Yox1p promotes its dissociation from the MBF transcription factor. We establish that phosphorylation of Yox1p at Ser114, Thr115 is required for maximal checkpoint-dependent activation of the G1/S cell-cycle transcriptional program. Conclusions/Significance This study shows that checkpoint-dependent phosphorylation of Yox1p at Ser114, Thr115 results in de-repression of the MBF transcriptional program. The remodeling of the cell cycle transcriptional program by the DNA replication checkpoint is likely to comprise an important mechanism for the avoidance of genomic instability.
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Affiliation(s)
- Catia Caetano
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Steffi Klier
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Robertus A. M. de Bruin
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
- * E-mail:
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28
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Global dissociation of HuR-mRNA complexes promotes cell survival after ionizing radiation. EMBO J 2011; 30:1040-53. [PMID: 21317874 DOI: 10.1038/emboj.2011.24] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 01/13/2011] [Indexed: 12/31/2022] Open
Abstract
Ionizing radiation (IR) triggers adaptive changes in gene expression. Here, we show that survival after IR strongly depends on the checkpoint kinase Chk2 acting upon its substrate HuR, an RNA-binding protein that stabilizes and/or modulates the translation of target mRNAs. Microarray analysis showed that in human HCT116 colorectal carcinoma cells (WT), IR-activated Chk2 triggered the dissociation of virtually all of HuR-bound mRNAs, since IR did not dissociate HuR target mRNAs in Chk2-null (CHK2-/-) HCT116 cells. Accordingly, several HuR-interacting mRNAs encoding apoptosis- and proliferation-related proteins (TJP1, Mdm2, TP53BP2, Bax, K-Ras) dissociated from HuR in WT cells, but remained bound and showed altered post-transcriptional regulation in CHK2-/- cells. Use of HuR mutants that were not phosphorylatable by Chk2 (HuR(3A)) and HuR mutants mimicking constitutive phosphorylation by Chk2 (HuR(3D)) revealed that dissociation of HuR target transcripts enhanced cell survival. We propose that the release of HuR-bound mRNAs via an IR-Chk2-HuR regulatory axis improves cell outcome following IR.
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29
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Ozaki T, Kubo N, Nakagawara A. p73-Binding Partners and Their Functional Significance. INTERNATIONAL JOURNAL OF PROTEOMICS 2011; 2010:283863. [PMID: 22084676 PMCID: PMC3195385 DOI: 10.1155/2010/283863] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 10/26/2010] [Indexed: 12/21/2022]
Abstract
p73 is one of the tumor-suppressor p53 family of nuclear transcription factor. As expected from the structural similarity between p53 and p73, p73 has a tumor-suppressive function. However, p73 was rarely mutated in human primary tumors. Under normal physiological conditions, p73 is kept at an extremely low level to allow cells normal growth. In response to a certain subset of DNA damages, p73 is induced dramatically and transactivates an overlapping set of p53-target genes implicated in the promotion of cell cycle arrest and/or apoptotic cell death. Cells undergo cell cycle arrest and/or apoptotic cell death depending on the type and strength of DNA damages. p73 is regulated largely through the posttranslational modifications such as phosphorylation and acetylation. These chemical modifications are tightly linked to direct protein-protein interactions. In the present paper, the authors describe the functional significance of the protein-protein interactions in the regulation of proapoptotic p73.
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Affiliation(s)
- Toshinori Ozaki
- Laboratory of Anti-tumor Research, Chiba Cancer Center Research Institute, Chiba 260-8717, Japan
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30
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Yox1 links MBF-dependent transcription to completion of DNA synthesis. EMBO Rep 2010; 12:84-9. [PMID: 21132016 DOI: 10.1038/embor.2010.187] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 10/14/2010] [Accepted: 10/29/2010] [Indexed: 12/15/2022] Open
Abstract
When DNA replication is challenged cells activate a DNA synthesis checkpoint, blocking cell cycle progression until they are able to overcome the replication defects. In fission yeast, Cds1 is the effector kinase of this checkpoint, inhibiting M-phase entry, stabilizing stalled replication forks and triggering transcriptional activation of S-phase genes. The molecular basis of this last effect is largely unknown. The Mlu1 binding factor (MBF) complex controls the transcription of S-phase genes. We purified novel interactors of the MBF complex and identified the repressor Yox1. When the DNA synthesis checkpoint is activated, Yox1 is phosphorylated, which abrogates its binding to MBF. MBF-dependent transcription therefore remains active until cells are able to overcome this challenge.
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31
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Gondi CS, Gogineni VR, Chetty C, Dasari VR, Gorantla B, Gujrati M, Dinh DH, Rao JS. Induction of apoptosis in glioma cells requires cell-to-cell contact with human umbilical cord blood stem cells. Int J Oncol 2010; 36:1165-73. [PMID: 20372790 DOI: 10.3892/ijo_00000599] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We have previously demonstrated the multipotent nature of human umbilical cord blood stem cells (hUCB). In this study, we have attempted to show the use of hUCB in glioma therapy. We used hUCB enriched in CD44 and CD133 cells for our studies and observed that glioma cells co-cultured with hUCB undergo apoptosis. To prove the role of cell-to-cell contact in the induction of apoptotic events, we used a modified 0.22 microm Boyden's chamber where the upper surface was used to culture glioma cells (SNB19 or U87) or xenografts (4910 or 5310) and the lower surface to culture hUCB. TUNEL assay was carried out to determine the degree of apoptotic induction and we observed that glioma or xenograft cells co-cultured with hUCB had a higher number of TUNEL-positive characteristics (63+/-6%) compared to the controls. Further, we co-cultured glioma cells labeled with lipophilic green fluorescent dye and hUCB labeled with lipophilic red fluorescent dye. FACS analysis of cells collected from the upper and lower surfaces revealed that glioma cells had taken up red fluorescent dye from the stem cells (70+/-3%) when compared to glioma cells co-cultured with fibroblast cells (15+/-4%). The apoptotic events in the glioma and xenograft cells co-cultured with hUCB were also confirmed by Western blot analysis for the cleavage of PARP and activation of caspase 8. In addition, elevated levels of CHK-2 levels and downregulation of MAP2K1 were observed in glioma cells co-cultured with hUCB indicating the DNA damage and decrease in cell survival. Nude mice, intracranially implanted with luciferase-expressing U87 cells followed by implantation of hUCB or human fibroblast cells showed retardation of intracranial tumors in hUCB-implanted mice. Taken together, these results demonstrate that hUCB have therapeutic potential with possible clinical implications.
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Affiliation(s)
- Christopher S Gondi
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL 61605, USA
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32
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Alao JP, Huis In 't Veld PJ, Buhse F, Sunnerhagen P. Hyperosmosis enhances radiation and hydroxyurea resistance of Schizosaccharomyces pombe checkpoint mutants through the spindle checkpoint and delayed cytokinesis. Mol Microbiol 2010; 77:143-57. [PMID: 20444100 DOI: 10.1111/j.1365-2958.2010.07193.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The DNA damage and stress response pathways interact to regulate cellular responses to genotoxins and environmental stresses. How these pathways interact in Schizosaccharomyces pombe is not well understood. We demonstrate that osmotic stress suppresses the DNA damage sensitivity of checkpoint mutants, and that this occurs through three distinct cell cycle delays. A delay in G2/M is dependent on Srk1. Progression through mitosis is halted by the Mad2-dependent spindle checkpoint. Finally, cytokinesis is impaired by modulating Cdc25 expression. These three delays, imposed by osmotic stress, together compensate for the loss of checkpoint signalling.
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Affiliation(s)
- John P Alao
- Department of Cell and Molecular Biology, Lundberg Laboratory, University of Gothenburg, P.O. Box 462, S-405 30 Göteborg, Sweden
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Alao JP, Olesch J, Sunnerhagen P. Inhibition of type I histone deacetylase increases resistance of checkpoint-deficient cells to genotoxic agents through mitotic delay. Mol Cancer Ther 2009; 8:2606-15. [PMID: 19723888 DOI: 10.1158/1535-7163.mct-09-0218] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Histone deacetylase (HDAC) inhibitors potently inhibit tumor growth and are currently being evaluated for their efficacy as chemosensitizers and radiosensitizers. This efficacy is likely to be limited by the fact that HDAC inhibitors also induce cell cycle arrest. Deletion of the class I HDAC Rpd3 has been shown to specifically suppress the sensitivity of Saccharomyces cerevisiae DNA damage checkpoint mutants to UV and hydroxyurea. We show that in the fission yeast Schizosaccharomyces pombe, inhibition of the homologous class I HDAC specifically suppresses the DNA damage sensitivity of checkpoint mutants. Importantly, the prototype HDAC inhibitor Trichostatin A also suppressed the sensitivity of DNA damage checkpoint but not of DNA repair mutants to UV and HU. TSA suppressed DNA damage activity independently of the mitogen-activated protein kinase-dependent and spindle checkpoint pathways. We show that TSA delays progression into mitosis and propose that this is the main mechanism for suppression of the DNA damage sensitivity of S. pombe checkpoint mutants, partially compensating for the loss of the G(2) checkpoint pathway. Our studies also show that the ability of HDAC inhibitors to suppress DNA damage sensitivity is not species specific. Class I HDACs are the major target of HDAC inhibitors and cancer cells are often defective in checkpoint activation. Effective use of these agents as chemosensitizers and radiosensitizers may require specific treatment schedules that circumvent their inhibition of cell cycle progression.
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Affiliation(s)
- John P Alao
- Department of Cell and Molecular Biology, Lundberg Laboratory, University of Gothenburg, S-405 30 Göteborg, Sweden
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Growth pattern of single fission yeast cells is bilinear and depends on temperature and DNA synthesis. Biophys J 2009; 96:4336-47. [PMID: 19450504 DOI: 10.1016/j.bpj.2009.02.051] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 02/11/2009] [Accepted: 02/19/2009] [Indexed: 11/20/2022] Open
Abstract
Cell growth and division have to be tightly coordinated to keep the cell size constant over generations. Changes in cell size can be easily studied in the fission yeast Schizosaccharomyces pombe because these cells have a cylindrical shape and grow only at the cell ends. However, the growth pattern of single cells is currently unclear. Linear, exponential, and bilinear growth models have been proposed. Here we measured the length of single fission yeast cells with high spatial precision and temporal resolution over the whole cell cycle by using time-lapse confocal microscopy of cells with green fluorescent protein-labeled plasma membrane. We show that the growth profile between cell separation and the subsequent mitosis is bilinear, consisting of two linear segments separated by a rate-change point (RCP). The change in growth rate occurred at the same relative time during the cell cycle and at the same relative extension for different temperatures. The growth rate before the RCP was independent of temperature, whereas the growth rate after the RCP increased with an increase in temperature, leading to clear bilinear growth profiles at higher temperatures. The RCP was not directly related to the initiation of growth at the new end (new end take-off). When DNA synthesis was inhibited by hydroxyurea, the RCP was not detected. This result suggests that completion of DNA synthesis is required for the increase in growth rate. We conclude that the growth of fission yeast cells is not a simple exponential growth, but a complex process with precise rates regulated by the events during the cell cycle.
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35
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A Cds1-mediated checkpoint protects the MBF activator Rep2 from ubiquitination by anaphase-promoting complex/cyclosome-Ste9 at S-phase arrest in fission yeast. Mol Cell Biol 2009; 29:4959-70. [PMID: 19596787 DOI: 10.1128/mcb.00562-09] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transcription of the MluI cell cycle box (MCB) motif-containing genes at G(1) phase is regulated by the MCB-binding factors (MBF) (also called DSC1) in Schizosaccharomyces pombe. Upon S-phase arrest, the MBF transcriptional activity is induced through the accumulation of the MBF activator Rep2. In this study, we show that the turnover of Rep2 is attributable to ubiquitin-mediated proteolysis. Levels of Rep2 oscillate during the cell cycle, with a peak at G(1) phase, coincident with the MBF activity. Furthermore, we show that Rep2 ubiquitination requires the function of the E3 ligase anaphase-promoting complex/cyclosome (APC/C). Ste9 can be phosphorylated by the checkpoint kinase Cds1 in vitro, and its inhibition/phosphorylation at S-phase arrest is dependent on the function of Cds1. Our data indicate that the Cds1-dependent stabilization of Rep2 is achieved through the inhibition/phosphorylation of APC/C-Ste9 at the onset of S-phase arrest. Stabilization of Rep2 is important for stimulating transcription of the MBF-dependent genes to ensure a sufficient supply of proteins essential for cell recovery from S-phase arrest. We propose that oscillation of Rep2 plays a role in regulation of periodic transcription of the MBF-dependent genes during cell cycle progression.
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36
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Paparatto D, Fletcher D, Piwowar K, Baldino K, Morel C, Dunaway S. The Schizosaccharomyces pombe checkpoint kinases Chk1 and Cds1 are important for cell survival in response to cisplatin. PLoS One 2009; 4:e6181. [PMID: 19587778 PMCID: PMC2702685 DOI: 10.1371/journal.pone.0006181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Accepted: 06/11/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND DNA damage checkpoints insure that the integrity of genomic DNA is faithfully maintained throughout the eukaryotic cell cycle. In the presence of damaged DNA, checkpoints are triggered to delay cell cycle progression to allow for DNA repair. In fission yeast, the kinases Chk1 and Cds1 are major components of these DNA damage checkpoint pathways. Both Chk1 and Cds1 are important for viability in the presence of several DNA damaging agents. In this study we hypothesized that Chk1 and Cds1 play a vital role in fission yeast cells ability to survive exposure to the DNA damaging agent cisplatin. Cisplatin is a potent chemotherapeutic drug that interacts with DNA and causes both inter- and intra-strand DNA cross-links. METHODOLOGY/PRINCIPAL FINDINGS Here, we demonstrated that treatment with cisplatin in fission yeast causes a Chk1-dependent DNA damage signal. chk1(-) cells were sensitive to cisplatin and Chk1 was phosphorylated in response to cisplatin treatment. We also showed that a Chk1-dependent DNA damage checkpoint pathway is activated in a dose-dependent fashion in cells challenged with cisplatin. Furthermore the Cds1 checkpoint kinase was also important for viability in cisplatin challenged cells. In cds1(-) cells, cisplatin treatment reduced cell viability and this phenotype was exacerbated in a chk1(-)/cds1(-) background. CONCLUSIONS/SIGNIFICANCE Thus, we conclude that the concerted effort of both major checkpoint kinases in fission yeast, Chk1 and Cds1, protect cells from cisplatin induced DNA damage. These observations are significant because they suggest that various classes of inter-strand crosslinking agents may generate slightly different lesions as work by others did not observe loss of viability in cds1(-) cells treated with other crosslinking agents like nitrogen mustard.
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Affiliation(s)
- Domenica Paparatto
- Department of Biology, Drew University, Madison, New Jersey, United States of America
| | - Dane Fletcher
- Department of Biology, Drew University, Madison, New Jersey, United States of America
| | - Karen Piwowar
- Department of Biology, Drew University, Madison, New Jersey, United States of America
| | - Kimberly Baldino
- Department of Biology, Drew University, Madison, New Jersey, United States of America
| | - Charlotte Morel
- Department of Biology, Drew University, Madison, New Jersey, United States of America
| | - Stephen Dunaway
- Department of Biology, Drew University, Madison, New Jersey, United States of America
- * E-mail:
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37
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Xu YJ, Kelly TJ. Autoinhibition and autoactivation of the DNA replication checkpoint kinase Cds1. J Biol Chem 2009; 284:16016-27. [PMID: 19357077 PMCID: PMC2708895 DOI: 10.1074/jbc.m900785200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 03/30/2009] [Indexed: 11/06/2022] Open
Abstract
Cds1 is the ortholog of Chk2 and the major effector of the DNA replication checkpoint in Schizosaccharomyces pombe. Previous studies have shown that Cds1 is activated by a two-stage mechanism. In the priming stage, the sensor kinase Rad3 and the mediator Mrc1 function to phosphorylate a threonine residue, Thr(11), in the SQ/TQ domain of Cds1. In the autoactivation stage, primed Cds1 molecules dimerize via intermolecular interactions between the phosphorylated Thr(11) in one Cds1 and the forkhead-associated domain of the other. Dimerization activates Cds1, probably by promoting autophosphorylation. To define the mechanisms for the autoactivation of primed Cds1 and the regulation of this process, we carried out genetic and biochemical studies to identify phosphorylatable residues required for checkpoint activation. Our data indicate that dimerization of Cds1 promotes trans-autophosphorylation of a number of residues in the catalytic domain, but phosphorylation of a highly conserved threonine residue (Thr(328)) in the activation loop is the only covalent modification required for kinase activation in vitro and in vivo. Autophosphorylation of Thr(328) and kinase activation in unprimed, monomeric Cds1 are strongly inhibited by the C-terminal 27-amino acid tail of the enzyme. This autoinhibitory effect may play an important role in preventing spontaneous activation of the replication checkpoint during normal cell cycles. The two-stage activation pathway and the autoinhibition mechanism, which are probably shared by other members of the Chk2 family, provide sensitivity, specificity, and noise immunity, properties required for the replication checkpoint.
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Affiliation(s)
- Yong-jie Xu
- From the Program in Molecular Biology, Sloan-Kettering Institute, New York, New York 10021 and the
- Department of Biochemistry and Molecular Biology, Wright State University School of Medicine, Dayton, Ohio 45435
| | - Thomas J. Kelly
- From the Program in Molecular Biology, Sloan-Kettering Institute, New York, New York 10021 and the
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38
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Yeh YH, Huang YF, Lin TY, Shieh SY. The cell cycle checkpoint kinase CHK2 mediates DNA damage-induced stabilization of TTK/hMps1. Oncogene 2009; 28:1366-78. [PMID: 19151762 DOI: 10.1038/onc.2008.477] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Cell cycle progression is monitored constantly to ensure faithful passage of genetic codes and genome stability. We have demonstrated previously that, upon DNA damage, TTK/hMps1 activates the checkpoint kinase CHK2 by phosphorylating CHK2 at Thr68. However, it remains to be determined whether and how TTK/hMps1 responds to DNA damage. In this report, we present evidence that TTK/hMps1 can be induced by DNA damage in normal human fibroblasts. Interestingly, the induction depends on CHK2 because CHK2-targeting small interfering RNA or a CHK2 inhibitor abolishes the increase. Such induction is mediated through phosphorylation of TTK/hMps1 at Thr288 by CHK2 and requires the CHK2 SQ/TQ cluster domain/forkhead-associated domain. In cells, TTK/hMps1 phosphorylation at Thr288 is induced by DNA damage and forms nuclear foci, which colocalize partially with gamma-H2AX. Reexpression of TTK/hMps1 T288A mutant in TTK/hMps1-knockdown cells causes a defect in G(2)/M arrest, suggesting that phosphorylation at this site participates in the proper checkpoint execution. Our study uncovered a regulatory loop between TTK/hMps1 and CHK2 whereby DNA damage-activated CHK2 may facilitate the stabilization of TTK/hMps1, therefore maintaining the checkpoint control.
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Affiliation(s)
- Y-H Yeh
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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Doller A, Pfeilschifter J, Eberhardt W. Signalling pathways regulating nucleo-cytoplasmic shuttling of the mRNA-binding protein HuR. Cell Signal 2008; 20:2165-73. [DOI: 10.1016/j.cellsig.2008.05.007] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Accepted: 05/12/2008] [Indexed: 11/16/2022]
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Münch C, Kirsch S, Fernandes AMG, Schempp W. Evolutionary analysis of the highly dynamic CHEK2 duplicon in anthropoids. BMC Evol Biol 2008; 8:269. [PMID: 18831734 PMCID: PMC2566985 DOI: 10.1186/1471-2148-8-269] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Accepted: 10/02/2008] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Segmental duplications (SDs) are euchromatic portions of genomic DNA (> or = 1 kb) that occur at more than one site within the genome, and typically share a high level of sequence identity (>90%). Approximately 5% of the human genome is composed of such duplicated sequences. Here we report the detailed investigation of CHEK2 duplications. CHEK2 is a multiorgan cancer susceptibility gene encoding a cell cycle checkpoint kinase acting in the DNA-damage response signalling pathway. The continuous presence of the CHEK2 gene in all eukaryotes and its important role in maintaining genome stability prompted us to investigate the duplicative evolution and phylogeny of CHEK2 and its paralogs during anthropoid evolution. RESULTS To study CHEK2 duplicon evolution in anthropoids we applied a combination of comparative FISH and in silico analyses. Our comparative FISH results with a CHEK2 fosmid probe revealed the single-copy status of CHEK2 in New World monkeys, Old World monkeys and gibbons. Whereas a single CHEK2 duplication was detected in orangutan, a multi-site signal pattern indicated a burst of duplication in African great apes and human. Phylogenetic analysis of paralogous and ancestral CHEK2 sequences in human, chimpanzee and rhesus macaque confirmed this burst of duplication, which occurred after the radiation of orangutan and African great apes. In addition, we used inter-species quantitative PCR to determine CHEK2 copy numbers. An amplification of CHEK2 was detected in African great apes and the highest CHEK2 copy number of all analysed species was observed in the human genome. Furthermore, we detected variation in CHEK2 copy numbers within the analysed set of human samples. CONCLUSION Our detailed analysis revealed the highly dynamic nature of CHEK2 duplication during anthropoid evolution. We determined a burst of CHEK2 duplication after the radiation of orangutan and African great apes and identified the highest CHEK2 copy number in human. In conclusion, our analysis of CHEK2 duplicon evolution revealed that SDs contribute to inter-species variation. Furthermore, our qPCR analysis led us to presume CHEK2 copy number variation in human, and molecular diagnostics of the cancer susceptibility gene CHEK2 inside the duplicated region might be hampered by the individual-specific set of duplicons.
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Affiliation(s)
- Claudia Münch
- Institute of Human Genetics and Anthropology, University of Freiburg, Breisacher Str. 33, 79106 Freiburg, Germany
| | - Stefan Kirsch
- Institute of Human Genetics and Anthropology, University of Freiburg, Breisacher Str. 33, 79106 Freiburg, Germany
| | - António MG Fernandes
- Institute of Human Genetics and Anthropology, University of Freiburg, Breisacher Str. 33, 79106 Freiburg, Germany
| | - Werner Schempp
- Institute of Human Genetics and Anthropology, University of Freiburg, Breisacher Str. 33, 79106 Freiburg, Germany
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Díaz-Cuervo H, Bueno A. Cds1 controls the release of Cdc14-like phosphatase Flp1 from the nucleolus to drive full activation of the checkpoint response to replication stress in fission yeast. Mol Biol Cell 2008; 19:2488-99. [PMID: 18385517 DOI: 10.1091/mbc.e07-08-0737] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The Cdc14p-like phosphatase Flp1p (also known as Clp1p) is regulated by cell cycle-dependent changes in its subcellular localization. Flp1p is restricted to the nucleolus and spindle pole body until prophase, when it is dispersed throughout the nucleus, mitotic spindle, and medial ring. Once released, Flp1p antagonizes Cdc2p/cyclin activity by reverting Cdc2p-phosphorylation sites on Cdc25p. On replication stress, ataxia-telangiectasia mutated/ATM/Rad3-related kinase Rad3p activates Cds1p, which phosphorylates key proteins ensuring the stability of stalled DNA replication forks. Here, we show that replication stress induces changes in the subcellular localization of Flp1p in a checkpoint-dependent manner. Active Cds1p checkpoint kinase is required to release Flp1p into the nucleus. Consistently, a Flp1p mutant (flp1-9A) lacking all potential Cds1p phosphorylation sites fails to relocate in response to replication blocks and, similarly to cells lacking flp1 (Deltaflp1), presents defects in checkpoint response to replication stress. Deltaflp1 cells accumulate reduced levels of a less active Cds1p kinase in hydroxyurea (HU), indicating that nuclear Flp1p regulates Cds1p full activation. Consistently, Deltaflp1 and flp1-9A have an increased percentage of Rad22p-recombination foci during HU treatment. Together, our data show that by releasing Flp1p into the nucleus Cds1p checkpoint kinase modulates its own full activation during replication stress.
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Affiliation(s)
- Helena Díaz-Cuervo
- Instituto de Biología Molecular y Celular del Cáncer, Departamento de Microbiología y Genética, Campus Miguel de Unamuno, Universidad de Salamanca/Consejo Superior de Investigaciones Científicas, 37007 Salamanca, Spain
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Alao JP, Sunnerhagen P. Rad3 and Sty1 function in Schizosaccharomyces pombe: an integrated response to DNA damage and environmental stress? Mol Microbiol 2008; 68:246-54. [DOI: 10.1111/j.1365-2958.2008.06147.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Palermo C, Hope JC, Freyer GA, Rao H, Walworth NC. Importance of a C-terminal conserved region of Chk1 for checkpoint function. PLoS One 2008; 3:e1427. [PMID: 18183307 PMCID: PMC2173936 DOI: 10.1371/journal.pone.0001427] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Accepted: 12/06/2007] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The protein kinase Chk1 is an essential component of the DNA damage checkpoint pathway. Chk1 is phosphorylated and activated in the fission yeast Schizosaccharomyces pombe when cells are exposed to agents that damage DNA. Phosphorylation, kinase activation, and nuclear accumulation are events critical to the ability of Chk1 to induce a transient delay in cell cycle progression. The catalytic domain of Chk1 is well-conserved amongst all species, while there are only a few regions of homology within the C-terminus. A potential pseudosubstrate domain exists in the C-terminus of S. pombe Chk1, raising the possibility that the C-terminus acts to inhibit the catalytic domain through interaction of this domain with the substrate binding site. METHODOLOGY/PRINCIPAL FINDINGS To evaluate this hypothesis, we characterized mutations in the pseudosubstrate region. Mutation of a conserved aspartic acid at position 469 to alanine or glycine compromises Chk1 function when the mutants are integrated as single copies, demonstrating that this domain of Chk1 is critical for function. Our data does not support, however, the hypothesis that the domain acts to inhibit Chk1 function as other mutations in the amino acids predicted to comprise the pseudosubstrate do not result in constitutive activation of the protein. When expressed in multi-copy, Chk1D469A remains non-functional. In contrast, multi-copy Chk1D469G confers cell survival and imposes a checkpoint delay in response to some, though not all forms of DNA damage. CONCLUSIONS/SIGNIFICANCE Thus, we conclude that this C-terminal region of Chk1 is important for checkpoint function and predict that a limiting factor capable of associating with Chk1D469G, but not Chk1D469A, interacts with Chk1 to elicit checkpoint activation in response to a subset of DNA lesions.
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Affiliation(s)
- Carmela Palermo
- Department of Pharmacology, University of Medicine and Dentistry, New Jersey (UMDNJ), Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
- Joint Graduate Program in Cellular and Molecular Pharmacology, University of Medicine and Dentistry, New Jersey (UMDNJ), Graduate School of Biomedical Sciences and Rutgers, State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Justin C. Hope
- Graduate Programs in Environmental Health Sciences and Anatomy and Cell Biology, Columbia University, New York, New York, United States of America
| | - Greg A. Freyer
- Graduate Programs in Environmental Health Sciences and Anatomy and Cell Biology, Columbia University, New York, New York, United States of America
| | - Hui Rao
- Joint Graduate Program in Cellular and Molecular Pharmacology, University of Medicine and Dentistry, New Jersey (UMDNJ), Graduate School of Biomedical Sciences and Rutgers, State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Nancy C. Walworth
- Department of Pharmacology, University of Medicine and Dentistry, New Jersey (UMDNJ), Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
- Joint Graduate Program in Cellular and Molecular Pharmacology, University of Medicine and Dentistry, New Jersey (UMDNJ), Graduate School of Biomedical Sciences and Rutgers, State University of New Jersey, Piscataway, New Jersey, United States of America
- The Cancer Institute of New Jersey, New Brunswick, New Jersey, United States of America
- * To whom correspondence should be addressed. E-mail:
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Antoni L, Sodha N, Collins I, Garrett MD. CHK2 kinase: cancer susceptibility and cancer therapy - two sides of the same coin? Nat Rev Cancer 2007; 7:925-36. [PMID: 18004398 DOI: 10.1038/nrc2251] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In the past decade, CHK2 has emerged as an important multifunctional player in the DNA-damage response signalling pathway. Parallel studies of the human CHEK2 gene have also highlighted its role as a candidate multiorgan tumour susceptibility gene rather than a highly penetrant predisposition gene for Li-Fraumeni syndrome. As discussed here, our current understanding of CHK2 function in tumour cells, in both a biological and genetic context, suggests that targeted modulation of the active kinase or exploitation of its loss in tumours could prove to be effective anti-cancer strategies.
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Affiliation(s)
- Laurent Antoni
- Cancer Research UK Centre for Cancer Therapeutics, Institute of Cancer Research, Haddow Laboratories, 15 Cotswold Road, Sutton, Surrey, SM2 5NG, UK
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Bell DW, Kim SH, Godwin AK, Schiripo TA, Harris PL, Haserlat SM, Wahrer DCR, Haiman CA, Daly MB, Niendorf KB, Smith MR, Sgroi DC, Garber JE, Olopade OI, Le Marchand L, Henderson BE, Altshuler D, Haber DA, Freedman ML. Genetic and functional analysis of CHEK2 (CHK2) variants in multiethnic cohorts. Int J Cancer 2007; 121:2661-7. [PMID: 17721994 PMCID: PMC3090684 DOI: 10.1002/ijc.23026] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The CHEK2-1100delC mutation is recurrent in the population and is a moderate risk factor for breast cancer. To identify additional CHEK2 mutations potentially contributing to breast cancer susceptibility, we sequenced 248 cases with early-onset disease; functionally characterized new variants and conducted a population-based case-control analysis to evaluate their contribution to breast cancer risk. We identified 1 additional null mutation and 5 missense variants in the germline of cancer patients. In vitro, the CHEK2-H143Y variant resulted in gross protein destabilization, while others had variable suppression of in vitro kinase activity using BRCA1 as a substrate. The germline CHEK2-1100delC mutation was present among 8/1,646 (0.5%) sporadic, 2/400 (0.5%) early-onset and 3/302 (1%) familial breast cancer cases, but undetectable amongst 2,105 multiethnic controls, including 633 from the US. CHEK2-positive breast cancer families also carried a deleterious BRCA1 mutation. 1100delC appears to be the only recurrent CHEK2 mutation associated with a potentially significant contribution to breast cancer risk in the general population. Another recurrent mutation with attenuated in vitro function, CHEK2-P85L, is not associated with increased breast cancer susceptibility, but exhibits a striking difference in frequency across populations with different ancestral histories. These observations illustrate the importance of genotyping ethnically diverse groups when assessing the impact of low-penetrance susceptibility alleles on population risk. Our findings highlight the notion that clinical testing for rare missense mutations within CHEK2 may have limited value in predicting breast cancer risk, but that testing for the 1100delC variant may be valuable in phenotypically- and geographically-selected populations.
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Affiliation(s)
- Daphne W Bell
- Massachusetts General Hospital Cancer Center, Charlestown, MA, USA.
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Froget B, Blaisonneau J, Lambert S, Baldacci G. Cleavage of stalled forks by fission yeast Mus81/Eme1 in absence of DNA replication checkpoint. Mol Biol Cell 2007; 19:445-56. [PMID: 18032583 DOI: 10.1091/mbc.e07-07-0728] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
During replication arrest, the DNA replication checkpoint plays a crucial role in the stabilization of the replisome at stalled forks, thus preventing the collapse of active forks and the formation of aberrant DNA structures. How this checkpoint acts to preserve the integrity of replication structures at stalled fork is poorly understood. In Schizosaccharomyces pombe, the DNA replication checkpoint kinase Cds1 negatively regulates the structure-specific endonuclease Mus81/Eme1 to preserve genomic integrity when replication is perturbed. Here, we report that, in response to hydroxyurea (HU) treatment, the replication checkpoint prevents S-phase-specific DNA breakage resulting from Mus81 nuclease activity. However, loss of Mus81 regulation by Cds1 is not sufficient to produce HU-induced DNA breaks. Our results suggest that unscheduled cleavage of stalled forks by Mus81 is permitted when the replisome is not stabilized by the replication checkpoint. We also show that HU-induced DNA breaks are partially dependent on the Rqh1 helicase, the fission yeast homologue of BLM, but are independent of its helicase activity. This suggests that efficient cleavage of stalled forks by Mus81 requires Rqh1. Finally, we identified an interplay between Mus81 activity at stalled forks and the Chk1-dependent DNA damage checkpoint during S-phase when replication forks have collapsed.
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Affiliation(s)
- Benoît Froget
- Institut Curie-Centre National de la Recherche Scientifique, Régulation de la réplication des eucaryotes, Université Paris Sud-XI, Bat 110, 91405 Orsay, France
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Fersht N, Hermand D, Hayles J, Nurse P. Cdc18/CDC6 activates the Rad3-dependent checkpoint in the fission yeast. Nucleic Acids Res 2007; 35:5323-37. [PMID: 17690116 PMCID: PMC2018612 DOI: 10.1093/nar/gkm527] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
A screen for genes that can ectopically activate a Rad3-dependent checkpoint block over mitosis in fission yeast has identified the DNA replication initiation factor cdc18 (known as CDC6 in other organisms). Either a stabilized form of Cdc18, the Cdc18-T6A phosphorylation mutant, or overexpression of wild type Cdc18, activate the Rad3-dependent S-M checkpoint in the apparent absence of detectable replication structures and gross DNA damage. This cell cycle block relies on the Rad checkpoint pathway and requires Chk1 phosphorylation and activation. Unexpectedly, Cdc18-T6A induces changes in the mobility of Chromosome III, affecting the size of a restriction fragment containing rDNA repeats and producing aberrant nucleolar structures. Recombination events within the rDNA appear to contribute at least in part to the cell cycle delay. We propose that an elevated level of Cdc18 activates the Rad3-dependent checkpoint either directly or indirectly, and additionally causes expansion of the rDNA repeats on Chromosome III.
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Affiliation(s)
- Naomi Fersht
- Cell Cycle Group, Cancer Research UK London Institute, London WC2A 3PX, UK.
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Eshaghi M, Karuturi RKM, Li J, Chu Z, Liu ET, Liu J. Global profiling of DNA replication timing and efficiency reveals that efficient replication/firing occurs late during S-phase in S. pombe. PLoS One 2007; 2:e722. [PMID: 17684567 PMCID: PMC1934932 DOI: 10.1371/journal.pone.0000722] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Accepted: 07/09/2007] [Indexed: 11/18/2022] Open
Abstract
Background During S. pombe S-phase, initiation of DNA replication occurs at multiple sites (origins) that are enriched with AT-rich sequences, at various times. Current studies of genome-wide DNA replication profiles have focused on the DNA replication timing and origin location. However, the replication and/or firing efficiency of the individual origins on the genomic scale remain unclear. Methodology/Principal Findings Using the genome-wide ORF-specific DNA microarray analysis, we show that in S. pombe, individual origins fire with varying efficiencies and at different times during S-phase. The increase in DNA copy number plotted as a function of time is approximated to the near-sigmoidal model, when considering the replication start and end timings at individual loci in cells released from HU-arrest. Replication efficiencies differ from origin to origin, depending on the origin's firing efficiency. We have found that DNA replication is inefficient early in S-phase, due to inefficient firing at origins. Efficient replication occurs later, attributed to efficient but late-firing origins. Furthermore, profiles of replication timing in cds1Δ cells are abnormal, due to the failure in resuming replication at the collapsed forks. The majority of the inefficient origins, but not the efficient ones, are found to fire in cds1Δ cells after HU removal, owing to the firing at the remaining unused (inefficient) origins during HU treatment. Conclusions/Significance Taken together, our results indicate that efficient DNA replication/firing occurs late in S-phase progression in cells after HU removal, due to efficient late-firing origins. Additionally, checkpoint kinase Cds1p is required for maintaining the efficient replication/firing late in S-phase. We further propose that efficient late-firing origins are essential for ensuring completion of DNA duplication by the end of S-phase.
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Affiliation(s)
- Majid Eshaghi
- Systems Biology, Genome Institute of Singapore, Singapore, Singapore
| | - R. Krishna M. Karuturi
- Computational and Mathematical Biology, Genome Institute of Singapore, Singapore, Singapore
| | - Juntao Li
- Computational and Mathematical Biology, Genome Institute of Singapore, Singapore, Singapore
| | - Zhaoqing Chu
- Systems Biology, Genome Institute of Singapore, Singapore, Singapore
| | - Edison T. Liu
- Cancer Biology, Genome Institute of Singapore, Singapore, Singapore
| | - Jianhua Liu
- Systems Biology, Genome Institute of Singapore, Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- * To whom correspondence should be addressed. E-mail:
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Morrison AJ, Kim JA, Person MD, Highland J, Xiao J, Wehr TS, Hensley S, Bao Y, Shen J, Collins SR, Weissman JS, Delrow J, Krogan NJ, Haber JE, Shen X. Mec1/Tel1 Phosphorylation of the INO80 Chromatin Remodeling Complex Influences DNA Damage Checkpoint Responses. Cell 2007; 130:499-511. [PMID: 17693258 DOI: 10.1016/j.cell.2007.06.010] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2005] [Revised: 04/30/2007] [Accepted: 06/01/2007] [Indexed: 01/23/2023]
Abstract
The yeast Mec1/Tel1 kinases, ATM/ATR in mammals, coordinate the DNA damage response by phosphorylating proteins involved in DNA repair and checkpoint pathways. Recently, ATP-dependent chromatin remodeling complexes, such as the INO80 complex, have also been implicated in DNA damage responses, although regulatory mechanisms that direct their function remain unknown. Here, we show that the Ies4 subunit of the INO80 complex is phosphorylated by the Mec1/Tel1 kinases during exposure to DNA-damaging agents. Mutation of Ies4's phosphorylation sites does not significantly affect DNA repair processes, but does influence DNA damage checkpoint responses. Additionally, ies4 phosphorylation mutants are linked to the function of checkpoint regulators, such as the replication checkpoint factors Tof1 and Rad53. These findings establish a chromatin remodeling complex as a functional component in the Mec1/Tel1 DNA damage signaling pathway that modulates checkpoint responses and suggest that posttranslational modification of chromatin remodeling complexes regulates their involvement in distinct processes.
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Affiliation(s)
- Ashby J Morrison
- Department of Carcinogenesis, Science Park Research Division, University of Texas M.D. Anderson Cancer Center, Smithville, TX 78957, USA
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Dovey CL, Russell P. Mms22 preserves genomic integrity during DNA replication in Schizosaccharomyces pombe. Genetics 2007; 177:47-61. [PMID: 17660542 PMCID: PMC2013719 DOI: 10.1534/genetics.107.077255] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The faithful replication of the genome, coupled with the accurate repair of DNA damage, is essential for the maintenance of chromosomal integrity. The MMS22 gene of Saccharomyces cerevisiae plays an important but poorly understood role in preservation of genome integrity. Here we describe a novel gene in Schizosaccharomyces pombe that we propose is a highly diverged ortholog of MMS22. Fission yeast Mms22 functions in the recovery from replication-associated DNA damage. Loss of Mms22 results in the accumulation of spontaneous DNA damage in the S- and G2-phases of the cell cycle and elevated genomic instability. There are severe synthetic interactions involving mms22 and most of the homologous recombination proteins but not the structure-specific endonuclease Mus81-Eme1, which is required for survival of broken replication forks. Mms22 forms spontaneous nuclear foci and colocalizes with Rad22 in cells treated with camptothecin, suggesting that it has a direct role in repair of broken replication forks. Moreover, genetic interactions with components of the DNA replication fork suggest that Mms2 functions in the coordination of DNA synthesis following damage. We propose that Mms22 functions directly at the replication fork to maintain genomic integrity in a pathway involving Mus81-Eme1.
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Affiliation(s)
- Claire L Dovey
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 90237, USA
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