1
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Robertson CM, Xue Y, Chowdhury S, Maringele L. A CDK-Dependent Phosphorylation of a Novel Domain of Rif1 Regulates its Function during Telomere Damage and Other Types of Stress. Mol Cell Biol 2023; 43:185-199. [PMID: 37140180 PMCID: PMC10184589 DOI: 10.1080/10985549.2023.2193768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023] Open
Abstract
Rif1 mediates telomere length, DNA replication, and DNA damage responses in budding yeast. Previous work identified several posttranslational modifications of Rif1, however none of these was shown to mediate the molecular or cellular responses to DNA damage, including telomere damage. We searched for such modifications using immunoblotting methods and the cdc13-1 and tlc1Δ models of telomere damage. We found that Rif1 is phosphorylated during telomere damage, and that serines 57 and 110 within a novel phospho-gate domain (PGD) of Rif1 are important for this modification, in cdc13-1 cells. The phosphorylation of Rif1 appeared to inhibit its accumulation on damaged chromosomes and the proliferation of cells with telomere damage. Moreover, we found that checkpoint kinases were upstream of this Rif1 phosphorylation and that the Cdk1 activity was essential for maintaining it. Apart from telomere damage, S57 and S110 were essential for Rif1 phosphorylation during the treatment of cells with genotoxic agents or during mitotic stress. We propose a speculative "Pliers" model to explain the role of the PGD phosphorylation during telomere and other types of damage.
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Affiliation(s)
- Cameron M Robertson
- Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Yuan Xue
- Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Shobir Chowdhury
- Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Laura Maringele
- Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
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2
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Ho TJ, Goswami D, Kuo WW, Kuo CH, Yen SC, Lin PY, Lin SZ, Hsieh DJY, Shibu MA, Huang CY. Artemisia argyi exhibits anti-aging effects through decreasing the senescence in aging stem cells. Aging (Albany NY) 2022; 14:6187-6201. [PMID: 35951373 PMCID: PMC9417221 DOI: 10.18632/aging.204210] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 07/01/2022] [Indexed: 11/25/2022]
Abstract
Aging is accompanied by functional loss of many cellular pathways, creating an increased risk of many age-related complications (ARC). Aging causes stem cell exhaustion with a concomitant increase in cellular dysfunction. Recently, interest in senotherapeutics has been growing rapidly to promote healthy aging and as an intervention for ARCs. This research focused on screening the senomorphic properties of Artemisia argyi, as an emerging strategy for longevity, and prevention or treatment of ARCs. In this study, we aimed to find the clinical efficacy of daily consumption of Artemisia argyi water extract (AAW) on aging. In vitro 0.1μM Doxorubicin induced senescent human adipose derived mesenchymal stem cells was treated with different concentrations of AAW to show its anti-aging effect. 15 months old SHR rats (n=6) were treated with 7.9 mg/ml AAW for 4 weeks and anti-aging effect was evaluated. In vitro study showed the protective effect of AAW in telomere shortening and helps in maintaining a balance in the expression of anti-aging protein Klotho and TERT. AAW effectively reduced mitochondrial superoxide and also provided a protective shield against senescence markers like over-expression of p21 and formation of double strand breaks, which is known to cause premature aging. Moreover, animal studies indicated that AAW promoted the expression of Klotho in naturally aging rats. In addition, AAW successfully restored the decline cardiac function and improved the grip strength and memory of aging rat. These findings showed that therapeutic targeting of senescent stem cells by AAW restored stem cell homeostasis and improves overall health.
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Affiliation(s)
- Tsung-Jung Ho
- Department of Chinese Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien 970, Taiwan.,Integration Center of Traditional Chinese and Modern Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien 970, Taiwan.,School of Post-Baccalaureate Chinese Medicine, College of Medicine, Tzu Chi University, Buddhist Tzu Chi Medical Foundation, Hualien 970, Taiwan
| | - Debakshee Goswami
- Cardiovascular and Mitochondrial Related Disease Research Center, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien 970, Taiwan
| | - Wei-Wen Kuo
- Department of Biological Science and Technology, China Medical University, Taichung 404, Taiwan
| | - Chia-Hua Kuo
- Department of Sports Sciences, University of Taipei, Taipei 111, Taiwan
| | - Shih Cheng Yen
- Buddhist Compassion Relief Tzu Chi Foundation, Hualien 970, Taiwan
| | - Pi-Yu Lin
- Buddhist Compassion Relief Tzu Chi Foundation, Hualien 970, Taiwan
| | - Shinn-Zong Lin
- Bioinnovation Center, Buddhist Tzu Chi Medical Foundation, Hualien 970, Taiwan.,Department of Neurosurgery, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien 970, Taiwan
| | - Dennis Jine-Yuan Hsieh
- Department of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung 40201, Taiwan
| | | | - Chih-Yang Huang
- Cardiovascular and Mitochondrial Related Disease Research Center, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien 970, Taiwan.,Graduate Institute of Biomedical Sciences, China Medical University, Taichung 404, Taiwan.,Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 404, Taiwan.,Department of Biotechnology, Asia University, Taichung 41354, Taiwan.,Center of General Education, Buddhist Tzu Chi Medical Foundation, Tzu Chi University of Science and Technology, Hualien 970, Taiwan
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3
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Guervilly JH, Blin M, Laureti L, Baudelet E, Audebert S, Gaillard PH. SLX4 dampens MutSα-dependent mismatch repair. Nucleic Acids Res 2022; 50:2667-2680. [PMID: 35166826 PMCID: PMC8934664 DOI: 10.1093/nar/gkac075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 01/20/2022] [Accepted: 01/25/2022] [Indexed: 12/12/2022] Open
Abstract
The tumour suppressor SLX4 plays multiple roles in the maintenance of genome stability, acting as a scaffold for structure-specific endonucleases and other DNA repair proteins. It directly interacts with the mismatch repair (MMR) protein MSH2 but the significance of this interaction remained unknown until recent findings showing that MutSβ (MSH2-MSH3) stimulates in vitro the SLX4-dependent Holliday junction resolvase activity. Here, we characterize the mode of interaction between SLX4 and MSH2, which relies on an MSH2-interacting peptide (SHIP box) that drives interaction of SLX4 with both MutSβ and MutSα (MSH2-MSH6). While we show that this MSH2 binding domain is dispensable for the well-established role of SLX4 in interstrand crosslink repair, we find that it mediates inhibition of MutSα-dependent MMR by SLX4, unravelling an unanticipated function of SLX4.
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Affiliation(s)
- Jean-Hugues Guervilly
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France
| | - Marion Blin
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France
| | - Luisa Laureti
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France
| | - Emilie Baudelet
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France
| | - Stéphane Audebert
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France
| | - Pierre-Henri Gaillard
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, Marseille, France
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4
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Yan S, Gao S, Zhou P. Multi-functions of exonuclease 1 in DNA damage response and cancer susceptibility. RADIATION MEDICINE AND PROTECTION 2021. [DOI: 10.1016/j.radmp.2021.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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5
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Kratz K, Artola-Borán M, Kobayashi-Era S, Koh G, Oliveira G, Kobayashi S, Oliveira A, Zou X, Richter J, Tsuda M, Sasanuma H, Takeda S, Loizou JI, Sartori AA, Nik-Zainal S, Jiricny J. FANCD2-Associated Nuclease 1 Partially Compensates for the Lack of Exonuclease 1 in Mismatch Repair. Mol Cell Biol 2021; 41:e0030321. [PMID: 34228493 PMCID: PMC8384067 DOI: 10.1128/mcb.00303-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 06/28/2021] [Indexed: 11/20/2022] Open
Abstract
Germline mutations in the mismatch repair (MMR) genes MSH2, MSH6, MLH1, and PMS2 are linked to cancer of the colon and other organs, characterized by microsatellite instability and a large increase in mutation frequency. Unexpectedly, mutations in EXO1, encoding the only exonuclease genetically implicated in MMR, are not linked to familial cancer and cause a substantially weaker mutator phenotype. This difference could be explained if eukaryotic cells possessed additional exonucleases redundant with EXO1. Analysis of the MLH1 interactome identified FANCD2-associated nuclease 1 (FAN1), a novel enzyme with biochemical properties resembling EXO1. We now show that FAN1 efficiently substitutes for EXO1 in MMR assays and that this functional complementation is modulated by its interaction with MLH1. FAN1 also contributes to MMR in vivo; cells lacking both EXO1 and FAN1 have an MMR defect and display resistance to N-methyl-N-nitrosourea (MNU) and 6-thioguanine (TG). Moreover, FAN1 loss amplifies the mutational profile of EXO1-deficient cells, suggesting that the two nucleases act redundantly in the same antimutagenic pathway. However, the increased drug resistance and mutator phenotype of FAN1/EXO1-deficient cells are less prominent than those seen in cells lacking MSH6 or MLH1. Eukaryotic cells thus apparently possess additional mechanisms that compensate for the loss of EXO1.
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Affiliation(s)
- Katja Kratz
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Mariela Artola-Borán
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Saho Kobayashi-Era
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
- Institute of Biochemistry of the ETH Zurich, Zurich, Switzerland
| | - Gene Koh
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
- Academic Department of Medical Genetics, The Clinical School, University of Cambridge, Cambridge, United Kingdom
- MRC Cancer Unit, The Clinical School, University of Cambridge, Cambridge, United Kingdom
| | - Goncalo Oliveira
- Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Centre, Medical University of Vienna, Vienna, Austria
| | - Shunsuke Kobayashi
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
- Institute of Biochemistry of the ETH Zurich, Zurich, Switzerland
| | - Andreia Oliveira
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
- Institute of Biochemistry of the ETH Zurich, Zurich, Switzerland
| | - Xueqing Zou
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
- Academic Department of Medical Genetics, The Clinical School, University of Cambridge, Cambridge, United Kingdom
- MRC Cancer Unit, The Clinical School, University of Cambridge, Cambridge, United Kingdom
| | - Julia Richter
- Institute of Biochemistry of the ETH Zurich, Zurich, Switzerland
| | - Masataka Tsuda
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hiroyuki Sasanuma
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shunichi Takeda
- Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Joanna I. Loizou
- Institute of Cancer Research, Department of Medicine I, Comprehensive Cancer Centre, Medical University of Vienna, Vienna, Austria
| | | | - Serena Nik-Zainal
- Academic Department of Medical Genetics, The Clinical School, University of Cambridge, Cambridge, United Kingdom
- MRC Cancer Unit, The Clinical School, University of Cambridge, Cambridge, United Kingdom
| | - Josef Jiricny
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
- Institute of Biochemistry of the ETH Zurich, Zurich, Switzerland
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6
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Inflammation, epigenetics, and metabolism converge to cell senescence and ageing: the regulation and intervention. Signal Transduct Target Ther 2021; 6:245. [PMID: 34176928 PMCID: PMC8236488 DOI: 10.1038/s41392-021-00646-9] [Citation(s) in RCA: 111] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 05/09/2021] [Accepted: 05/13/2021] [Indexed: 02/05/2023] Open
Abstract
Remarkable progress in ageing research has been achieved over the past decades. General perceptions and experimental evidence pinpoint that the decline of physical function often initiates by cell senescence and organ ageing. Epigenetic dynamics and immunometabolic reprogramming link to the alterations of cellular response to intrinsic and extrinsic stimuli, representing current hotspots as they not only (re-)shape the individual cell identity, but also involve in cell fate decision. This review focuses on the present findings and emerging concepts in epigenetic, inflammatory, and metabolic regulations and the consequences of the ageing process. Potential therapeutic interventions targeting cell senescence and regulatory mechanisms, using state-of-the-art techniques are also discussed.
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7
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Xie DF, Cheng RY, Fu X, Zhang XY, Price M, Lan YL, Wang CB, He XJ. A Combined Morphological and Molecular Evolutionary Analysis of Karst-Environment Adaptation for the Genus Urophysa (Ranunculaceae). FRONTIERS IN PLANT SCIENCE 2021; 12:667988. [PMID: 34177982 PMCID: PMC8223000 DOI: 10.3389/fpls.2021.667988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 05/12/2021] [Indexed: 06/13/2023]
Abstract
The karst environment is characterized by low soil water content, periodic water deficiency, and poor nutrient availability, which provides an ideal natural laboratory for studying the adaptive evolution of its inhabitants. However, how species adapt to such a special karst environment remains poorly understood. Here, transcriptome sequences of two Urophysa species (Urophysa rockii and Urophysa henryi), which are Chinese endemics with karst-specific distribution, and allied species in Semiaquilegia and Aquilegia (living in non-karst habitat) were collected. Single-copy genes (SCGs) were extracted to perform the phylogenetic analysis using concatenation and coalescent methods. Positively selected genes (PSGs) and clusters of paralogous genes (Mul_genes) were detected and subsequently used to conduct gene function annotation. We filtered 2,271 SCGs and the coalescent analysis revealed that 1,930 SCGs shared the same tree topology, which was consistent with the topology detected from the concatenated tree. Total of 335 PSGs and 243 Mul_genes were detected, and many were enriched in stress and stimulus resistance, transmembrane transport, cellular ion homeostasis, calcium ion transport, calcium signaling regulation, and water retention. Both molecular and morphological evidences indicated that Urophysa species evolved complex strategies for adapting to hostile karst environments. Our findings will contribute to a new understanding of genetic and phenotypic adaptive mechanisms of karst adaptation in plants.
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Affiliation(s)
- Deng-Feng Xie
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China
| | - Rui-Yu Cheng
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China
| | - Xiao Fu
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China
| | - Xiang-Yi Zhang
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China
| | - Megan Price
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China
| | - Yan-Ling Lan
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China
| | | | - Xing-Jin He
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China
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8
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Chakravarti D, LaBella KA, DePinho RA. Telomeres: history, health, and hallmarks of aging. Cell 2021; 184:306-322. [PMID: 33450206 DOI: 10.1016/j.cell.2020.12.028] [Citation(s) in RCA: 246] [Impact Index Per Article: 82.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 02/06/2023]
Abstract
The escalating social and economic burden of an aging world population has placed aging research at center stage. The hallmarks of aging comprise diverse molecular mechanisms and cellular systems that are interrelated and act in concert to drive the aging process. Here, through the lens of telomere biology, we examine how telomere dysfunction may amplify or drive molecular biological processes underlying each hallmark of aging and contribute to development of age-related diseases such as neurodegeneration and cancer. The intimate link of telomeres to aging hallmarks informs preventive and therapeutic interventions designed to attenuate aging itself and reduce the incidence of age-associated diseases.
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Affiliation(s)
- Deepavali Chakravarti
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Kyle A LaBella
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ronald A DePinho
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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9
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Yue L, Pei Y, Zhong L, Yang H, Wang Y, Zhang W, Chen N, Zhu Q, Gao J, Zhi M, Wen B, Zhang S, Xiang J, Wei Q, Liang H, Cao S, Lou H, Chen Z, Han J. Mthfd2 Modulates Mitochondrial Function and DNA Repair to Maintain the Pluripotency of Mouse Stem Cells. Stem Cell Reports 2020; 15:529-545. [PMID: 32679066 PMCID: PMC7419720 DOI: 10.1016/j.stemcr.2020.06.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 06/18/2020] [Accepted: 06/18/2020] [Indexed: 12/14/2022] Open
Abstract
The pluripotency of stem cells determines their developmental potential. While the pluripotency states of pluripotent stem cells are variable and interconvertible, the mechanisms underlying the acquisition and maintenance of pluripotency remain largely elusive. Here, we identified that methylenetetrahydrofolate dehydrogenase (NAD+-dependent), methenyltetrahydrofolate cyclohydrolase (Mthfd2) plays an essential role in maintaining embryonic stem cell pluripotency and promoting complete reprogramming of induced pluripotent stem cells. Mechanistically, in mitochondria, Mthfd2 maintains the integrity of the mitochondrial respiratory chain and prevents mitochondrial dysfunction. In the nucleus, Mthfd2 stabilizes the phosphorylation of EXO1 to support DNA end resection and promote homologous recombination repair. Our results revealed that Mthfd2 is a dual-function factor in determining the pluripotency of pluripotent stem cells through both mitochondrial and nuclear pathways, ultimately ensuring safe application of pluripotent stem cells.
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Affiliation(s)
- Liang Yue
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China; Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100083, China
| | - Yangli Pei
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China; School of Life Science and Engineering, Foshan University, Foshan, Guangdong 528231, China
| | - Liang Zhong
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China; Hebei Provincial Key Laboratory of Basic Medicine for Diabetes, The Shijiazhuang Second Hospital, Shijiazhuang, Hebei 050051, China
| | - Henry Yang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Yanliang Wang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Wei Zhang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Naixin Chen
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Qianqian Zhu
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Jie Gao
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Minglei Zhi
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Bingqiang Wen
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Shaopeng Zhang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Jinzhu Xiang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Qingqing Wei
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Hui Liang
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Suying Cao
- Animal Science and Technology College, Beijing University of Agriculture, Beijing 102206, China
| | - Huiqiang Lou
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Zhongzhou Chen
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Jianyong Han
- State Key Laboratory for Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China; Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100083, China.
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10
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Chen YS, Kang XR, Zhou ZH, Yang J, Xin Q, Ying CT, Zhang YP, Tao J. MiR-1908/EXO1 and MiR-203a/FOS, regulated by scd1, are associated with fracture risk and bone health in postmenopausal diabetic women. Aging (Albany NY) 2020; 12:9549-9584. [PMID: 32454462 PMCID: PMC7288911 DOI: 10.18632/aging.103227] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 04/13/2020] [Indexed: 12/13/2022]
Abstract
Background: Stearoyl–coenzyme A desaturase-1 (SCD1) can inhibit the development of diabetic bone disease by promoting osteogenesis. In this study, we examined whether this regulation by SCD1 is achieved by regulating the expression of related miRNAs. Methods: SCD1 expression levels were observed in human bone-marrow mesenchymal stem cells (BM-MSCs) of patients with type 2 diabetes mellitus (T2DM), and the effect of SCD1 on osteogenesis was observed in human adipose-derived MSCs transfected with the SCD1 lentiviral system. We designed a bioinformatics prediction model to select important differentially expressed miRNAs, and established protein–protein interaction and miRNA–mRNA networks. miRNAs and mRNAs were extracted and their differential expression was detected. The SCD1–miRNA–mRNA network was validated. Findings: SCD1 expression in bone marrow was downregulated in patients with T2DM and low-energy fracture, and SCD1 expression promotes BM-MSC osteogenic differentiation. The predictors in the nomogram were seven microRNAs, including hsa-miR-1908 and hsa-miR-203a. SCD1 inhibited the expression of CDKN1A and FOS, but promoted the expression of EXO1 and PLS1. miR-1908 was a regulator of EXO1 expression, and miR-203a was a regulator of FOS expression. Interpretation: The regulation of BM-MSCs by SCD1 is a necessary condition for osteogenesis through the miR-203a/FOS and miR-1908/EXO1 regulatory pathways.
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Affiliation(s)
- Yi-Sheng Chen
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai 200080, China
| | - Xue-Ran Kang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Zi-Hui Zhou
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai 200080, China
| | - Jiang Yang
- Department of Neurosurgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai 200080, China
| | - Qi Xin
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai 200080, China
| | - Chen-Ting Ying
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai 200080, China
| | - Yun-Peng Zhang
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai 200080, China
| | - Jie Tao
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai 200080, China
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11
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Song S, Perez JV, Svitko W, Ricketts MD, Dean E, Schultz D, Marmorstein R, Johnson FB. Rap1-mediated nucleosome displacement can regulate gene expression in senescent cells without impacting the pace of senescence. Aging Cell 2020; 19:e13061. [PMID: 31742863 PMCID: PMC6974733 DOI: 10.1111/acel.13061] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 09/19/2019] [Accepted: 10/13/2019] [Indexed: 01/18/2023] Open
Abstract
Cell senescence is accompanied, and in part mediated, by changes in chromatin, including histone losses, but underlying mechanisms are not well understood. We reported previously that during yeast cell senescence driven by telomere shortening, the telomeric protein Rap1 plays a major role in reprogramming gene expression by relocalizing hundreds of new target genes (called NRTS, for new Rap1 targets at senescence) to the promoters. This leads to two types of histone loss: Rap1 lowers histone level globally by repressing histone gene expression, and it also causes local nucleosome displacement at the promoters of upregulated NRTS. Here, we present evidence of direct binding between Rap1 and histone H3/H4 heterotetramers, and map amino acids involved in the interaction within the Rap1 SANT domain to amino acids 392-394 (SHY). Introduction of a point mutation within the native RAP1 locus that converts these residues to alanines (RAP1SHY ), and thus disrupts Rap1-H3/H4 interaction, does not interfere with Rap1 relocalization to NRTS at senescence, but prevents full nucleosome displacement and gene upregulation, indicating direct Rap1-H3/H4 contacts are involved in nucleosome displacement. Consistent with this, the histone H3/H4 chaperone Asf1 is similarly unnecessary for Rap1 localization to NRTS but is required for full Rap1-mediated nucleosome displacement and gene activation. Remarkably, RAP1SHY does not affect the pace of senescence-related cell cycle arrest, indicating that some changes in gene expression at senescence are not coupled to this arrest.
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Affiliation(s)
- Shufei Song
- Department of Biochemistry and Molecular Biophysics University of Pennsylvania Philadelphia PA USA
- Graduate Group in Biochemistry and Molecular Biophysics University of Pennsylvania Philadelphia PA USA
- Department of Pathology and Laboratory Medicine University of Pennsylvania Philadelphia PA USA
| | - Javier V. Perez
- Department of Pathology and Laboratory Medicine University of Pennsylvania Philadelphia PA USA
| | - William Svitko
- Department of Pathology and Laboratory Medicine University of Pennsylvania Philadelphia PA USA
| | - M. Daniel Ricketts
- Department of Biochemistry and Molecular Biophysics University of Pennsylvania Philadelphia PA USA
- Abramson Family Cancer Research Institute University of Pennsylvania Philadelphia PA USA
| | - Elliot Dean
- High‐Throughput Screening Core University of Pennsylvania Philadelphia PA USA
| | - David Schultz
- High‐Throughput Screening Core University of Pennsylvania Philadelphia PA USA
| | - Ronen Marmorstein
- Department of Biochemistry and Molecular Biophysics University of Pennsylvania Philadelphia PA USA
- Abramson Family Cancer Research Institute University of Pennsylvania Philadelphia PA USA
| | - F. Brad Johnson
- Department of Biochemistry and Molecular Biophysics University of Pennsylvania Philadelphia PA USA
- Department of Pathology and Laboratory Medicine University of Pennsylvania Philadelphia PA USA
- Institute on Aging University of Pennsylvania Philadelphia PA USA
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12
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Abstract
The field of aging research has progressed significantly over the past decades. Exogenously and endogenously inflicted molecular damage ranging from genotoxic to organellar damage drives the aging process. Repair mechanisms and compensatory responses counteract the detrimental consequences of the various damage types. Here, we discuss recent progress in understanding cellular mechanisms and interconnections between signaling pathways that control longevity. We summarize cell-autonomous and non-cell-autonomous mechanisms that impact the cellular and organismal aging process
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Affiliation(s)
- Robert Bayersdorf
- Institute for Genome Stability in Aging and Disease, Medical Faculty, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster for Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Björn Schumacher
- Institute for Genome Stability in Aging and Disease, Medical Faculty, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster for Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
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13
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Tümpel S, Rudolph KL. Quiescence: Good and Bad of Stem Cell Aging. Trends Cell Biol 2019; 29:672-685. [PMID: 31248787 DOI: 10.1016/j.tcb.2019.05.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/30/2019] [Accepted: 05/01/2019] [Indexed: 12/25/2022]
Abstract
Stem cells are required for lifelong homeostasis and regeneration of tissues and organs in mammals, but the function of stem cells declines during aging. To preserve stem cells during life, they are kept in a quiescent state with low metabolic and low proliferative activity. However, activation of quiescent stem cells - an essential process for organ homeostasis/regeneration - requires concerted and faithful regulation of multiple molecular circuits controlling biosynthetic processes, repair mechanisms, and metabolic activity. Thus, while protecting stem cell maintenance, quiescence comes at the cost of vulnerability during the process of stem cell activation. Here we discuss molecular and biochemical processes regulating stem cells' maintenance in and exit from quiescence and how age-related failures of these circuits can contribute to organism aging.
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Affiliation(s)
- Stefan Tümpel
- Research Group on Stem Cell Aging, Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - K Lenhard Rudolph
- Research Group on Stem Cell Aging, Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany.
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14
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Diao D, Wang H, Li T, Shi Z, Jin X, Sperka T, Zhu X, Zhang M, Yang F, Cong Y, Shen L, Zhan Q, Yan J, Song Z, Ju Z. Telomeric epigenetic response mediated by Gadd45a regulates stem cell aging and lifespan. EMBO Rep 2018; 19:embr.201745494. [PMID: 30126922 DOI: 10.15252/embr.201745494] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 07/26/2018] [Accepted: 07/27/2018] [Indexed: 12/17/2022] Open
Abstract
Progressive attrition of telomeres triggers DNA damage response (DDR) and limits the regenerative capacity of adult stem cells during mammalian aging. Intriguingly, telomere integrity is not only determined by telomere length but also by the epigenetic status of telomeric/sub-telomeric regions. However, the functional interplay between DDR induced by telomere shortening and epigenetic modifications in aging remains unclear. Here, we show that deletion of Gadd45a improves the maintenance and function of intestinal stem cells (ISCs) and prolongs lifespan of telomerase-deficient mice (G3Terc -/-). Mechanistically, Gadd45a facilitates the generation of a permissive chromatin state for DDR signaling by inducing base excision repair-dependent demethylation of CpG islands specifically at sub-telomeric regions of short telomeres. Deletion of Gadd45a promotes chromatin compaction in sub-telomeric regions and attenuates DDR initiation at short telomeres of G3Terc -/- ISCs. Treatment with a small molecule inhibitor of base excision repair reduces DDR and improves the maintenance and function of G3Terc -/- ISCs. Taken together, our study proposes a therapeutic approach to enhance stem cell function and prolong lifespan by targeting epigenetic modifiers.
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Affiliation(s)
- Daojun Diao
- Key Laboratory of Regenerative Medicine of Ministry of Education, Institute of Aging and Regenerative Medicine, Jinan University, Guangzhou, China
| | - Hu Wang
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, China
| | - Tangliang Li
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, China
| | - Zhencan Shi
- Key Laboratory of Regenerative Medicine of Ministry of Education, Institute of Aging and Regenerative Medicine, Jinan University, Guangzhou, China
| | | | - Tobias Sperka
- Leibniz Institute on Aging, Fritz Lipmann Institute (FLI), Jena, Germany
| | - Xudong Zhu
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, China
| | - Meimei Zhang
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, China
| | - Fan Yang
- Key Laboratory of Regenerative Medicine of Ministry of Education, Institute of Aging and Regenerative Medicine, Jinan University, Guangzhou, China
| | - Yusheng Cong
- Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, China
| | - Li Shen
- Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Qimin Zhan
- State Key Laboratory of Molecular Oncology and Cancer Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Jing Yan
- Zhejiang Hospital, Hangzhou, China
| | - Zhangfa Song
- Department of Colorectal Surgery, Sir Run Run Shaw Hospital affiliated to Zhejiang University, Hangzhou, China
| | - Zhenyu Ju
- Key Laboratory of Regenerative Medicine of Ministry of Education, Institute of Aging and Regenerative Medicine, Jinan University, Guangzhou, China .,Institute of Aging Research, School of Medicine, Hangzhou Normal University, Hangzhou, China
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15
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Wyatt MD, Reilly NM, Patel S, Rajesh P, Schools GP, Smiraldo PG, Pittman DL. Thiopurine-induced mitotic catastrophe in Rad51d-deficient mammalian cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2018; 59:38-48. [PMID: 28945288 PMCID: PMC5771848 DOI: 10.1002/em.22138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/09/2017] [Accepted: 08/09/2017] [Indexed: 06/07/2023]
Abstract
Thiopurines are part of a clinical regimen used for the treatment of autoimmune disorders and childhood acute lymphoblastic leukemia. However, despite these successes, there are also unintended consequences such as therapy-induced cancer in long-term survivors. Therefore, a better understanding of cellular responses to thiopurines will lead to improved and personalized treatment strategies. RAD51D is an important component of homologous recombination (HR), and our previous work established that mammalian cells defective for RAD51D are more sensitive to the thiopurine 6-thioguanine (6TG) and have dramatically increased numbers of multinucleated cells and chromosome instability. 6TG is capable of being incorporated into telomeres, and interestingly, RAD51D contributes to telomere maintenance, although the precise function of RAD51D at the telomeres remains unclear. We sought here to investigate: (1) the activity of RAD51D at telomeres, (2) the contribution of RAD51D to protect against 6TG-induced telomere damage, and (3) the fates of Rad51d-deficient cells following 6TG treatment. These results demonstrate that RAD51D is required for maintaining the telomeric 3' overhangs. As measured by γ-H2AX induction and foci formation, 6TG induced DNA damage in Rad51d-proficient and Rad51d-deficient cells. However, the extent of γ-H2AX telomere localization following 6TG treatment was higher in Rad51d-deficient cells than in Rad51d-proficient cells. Using live-cell imaging of 6TG-treated Rad51d-deficient cells, two predominant forms of mitotic catastrophe were found to contribute to the formation of multinucleated cells, failed division and restitution. Collectively, these findings provide a unique window into the role of the RAD51D HR protein during thiopurine induction of mitotic catastrophe. Environ. Mol. Mutagen. 59:38-48, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Michael D. Wyatt
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia SC 29208
| | - Nicole M. Reilly
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia SC 29208
| | - Shikha Patel
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia SC 29208
| | - Preeti Rajesh
- Department of Biotechnology, Sri Guru Granth Sahib World University, Fatehgarh Sahib, Punjab, India-140406
| | - Gary P. Schools
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia SC 29208
| | | | - Douglas L. Pittman
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia SC 29208
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16
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Gunes C, Avila AI, Rudolph KL. Telomeres in cancer. Differentiation 2017; 99:41-50. [PMID: 29291448 DOI: 10.1016/j.diff.2017.12.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 02/07/2023]
Abstract
Telomere shortening as a consequence of cell divisions during aging and chronic diseases associates with an increased cancer risk. Experimental data revealed that telomere shortening results in telomere dysfunction, which in turn affects tumorigenesis in two ways. First, telomere dysfunction suppresses tumor progression by the activation of DNA damage checkpoints, which induce cell cycle arrest (senescence) or apoptosis, as well as by inducing metabolic compromise and activation of immune responses directed against senescent cells. Second, telomere dysfunction promotes tumorigenesis by inducing chromosomal instability in tumor initiating cells, by inhibiting proliferative competition of non-transformed cells, and possibly, also by influencing tumor cell plasticity. The tumor promoting effects of telomere dysfunction are context dependent and require the loss of p53-dependent DNA damage checkpoints or other genetic modifiers that attenuate DNA damage responses possibly involving complex interactions of different genes. The activation of telomere stabilizing mechanisms appears as a subsequent step, which is required to enable immortal grotwh of emerging cancer cells. Here, we conceptually discuss our current knowledge and new, unpublished experimental data on telomere dependent influences on tumor initiation and progression.
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Affiliation(s)
| | - Alush Irene Avila
- Research Group on Stem Cell Aging, Leibniz Institute on Aging, Fritz Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - K Lenhard Rudolph
- Research Group on Stem Cell Aging, Leibniz Institute on Aging, Fritz Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany.
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17
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Chappell GA, Israel JW, Simon JM, Pott S, Safi A, Eklund K, Sexton KG, Bodnar W, Lieb JD, Crawford GE, Rusyn I, Furey TS. Variation in DNA-Damage Responses to an Inhalational Carcinogen (1,3-Butadiene) in Relation to Strain-Specific Differences in Chromatin Accessibility and Gene Transcription Profiles in C57BL/6J and CAST/EiJ Mice. ENVIRONMENTAL HEALTH PERSPECTIVES 2017; 125:107006. [PMID: 29038090 PMCID: PMC5944832 DOI: 10.1289/ehp1937] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 08/30/2017] [Accepted: 09/05/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND The damaging effects of exposure to environmental toxicants differentially affect genetically distinct individuals, but the mechanisms contributing to these differences are poorly understood. Genetic variation affects the establishment of the gene regulatory landscape and thus gene expression, and we hypothesized that this contributes to the observed heterogeneity in individual responses to exogenous cellular insults. OBJECTIVES We performed an in vivo study of how genetic variation and chromatin organization may dictate susceptibility to DNA damage, and influence the cellular response to such damage, caused by an environmental toxicant. MATERIALS AND METHODS We measured DNA damage, messenger RNA (mRNA) and microRNA (miRNA) expression, and genome-wide chromatin accessibility in lung tissue from two genetically divergent inbred mouse strains, C57BL/6J and CAST/EiJ, both in unexposed mice and in mice exposed to a model DNA-damaging chemical, 1,3-butadiene. RESULTS Our results showed that unexposed CAST/EiJ and C57BL/6J mice have very different chromatin organization and transcription profiles in the lung. Importantly, in unexposed CAST/EiJ mice, which acquired relatively less 1,3-butadiene-induced DNA damage, we observed increased transcription and a more accessible chromatin landscape around genes involved in detoxification pathways. Upon chemical exposure, chromatin was significantly remodeled in the lung of C57BL/6J mice, a strain that acquired higher levels of 1,3-butadiene-induced DNA damage, around the same genes, ultimately resembling the molecular profile of CAST/EiJ. CONCLUSIONS These results suggest that strain-specific changes in chromatin and transcription in response to chemical exposure lead to a "compensation" for underlying genetic-driven interindividual differences in the baseline chromatin and transcriptional state. This work represents an example of how chemical and environmental exposures can be evaluated to better understand gene-by-environment interactions, and it demonstrates the important role of chromatin response in transcriptomic changes and, potentially, in deleterious effects of exposure. https://doi.org/10.1289/EHP1937.
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Affiliation(s)
- Grace A Chappell
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station , Texas, USA
- Department of Environmental Sciences and Engineering, University of North Carolina , Chapel Hill, North Carolina, USA
| | - Jennifer W Israel
- Department of Genetics, University of North Carolina , Chapel Hill, North Carolina, USA
| | - Jeremy M Simon
- Department of Genetics, University of North Carolina , Chapel Hill, North Carolina, USA
| | - Sebastian Pott
- Department of Human Genetics, University of Chicago , Chicago, Illinois, USA
| | - Alexias Safi
- Department of Pediatrics, Duke Center for Genomic and Computational Biology, Duke University , Durham, North Carolina, USA
| | - Karl Eklund
- Department of Genetics, University of North Carolina , Chapel Hill, North Carolina, USA
| | - Kenneth G Sexton
- Department of Environmental Sciences and Engineering, University of North Carolina , Chapel Hill, North Carolina, USA
| | - Wanda Bodnar
- Department of Environmental Sciences and Engineering, University of North Carolina , Chapel Hill, North Carolina, USA
| | - Jason D Lieb
- Department of Human Genetics, University of Chicago , Chicago, Illinois, USA
| | - Gregory E Crawford
- Department of Pediatrics, Duke Center for Genomic and Computational Biology, Duke University , Durham, North Carolina, USA
| | - Ivan Rusyn
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station , Texas, USA
| | - Terrence S Furey
- Department of Genetics, University of North Carolina , Chapel Hill, North Carolina, USA
- Department of Biology, University of North Carolina , Chapel Hill, North Carolina, USA
- UNC Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine , Chapel Hill, North Carolina, USA
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18
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Keijzers G, Liu D, Rasmussen LJ. Exonuclease 1 and its versatile roles in DNA repair. Crit Rev Biochem Mol Biol 2016; 51:440-451. [PMID: 27494243 DOI: 10.1080/10409238.2016.1215407] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Exonuclease 1 (EXO1) is a multifunctional 5' → 3' exonuclease and a DNA structure-specific DNA endonuclease. EXO1 plays roles in DNA replication, DNA mismatch repair (MMR) and DNA double-stranded break repair (DSBR) in lower and higher eukaryotes and contributes to meiosis, immunoglobulin maturation, and micro-mediated end-joining in higher eukaryotes. In human cells, EXO1 is also thought to play a role in telomere maintenance. Mutations in the human EXO1 gene correlate with increased susceptibility to some cancers. This review summarizes recent studies on the enzymatic functions and biological roles of EXO1, its possible protective role against cancer and aging, and regulation of EXO1 by posttranslational modification.
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Affiliation(s)
- Guido Keijzers
- a Department of Cellular and Molecular Medicine , Center for Healthy Aging, University of Copenhagen , Copenhagen , Denmark
| | - Dekang Liu
- a Department of Cellular and Molecular Medicine , Center for Healthy Aging, University of Copenhagen , Copenhagen , Denmark
| | - Lene Juel Rasmussen
- a Department of Cellular and Molecular Medicine , Center for Healthy Aging, University of Copenhagen , Copenhagen , Denmark
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19
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Xue Y, Marvin ME, Ivanova IG, Lydall D, Louis EJ, Maringele L. Rif1 and Exo1 regulate the genomic instability following telomere losses. Aging Cell 2016; 15:553-62. [PMID: 27004475 PMCID: PMC4854909 DOI: 10.1111/acel.12466] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/17/2016] [Indexed: 12/22/2022] Open
Abstract
Telomere attrition is linked to cancer, diabetes, cardiovascular disease and aging. This is because telomere losses trigger further genomic modifications, culminating with loss of cell function and malignant transformation. However, factors regulating the transition from cells with short telomeres, to cells with profoundly altered genomes, are little understood. Here, we use budding yeast engineered to lack telomerase and other forms of telomere maintenance, to screen for such factors. We show that initially, different DNA damage checkpoint proteins act together with Exo1 and Mre11 nucleases, to inhibit proliferation of cells undergoing telomere attrition. However, this situation changes when survivors lacking telomeres emerge. Intriguingly, checkpoint pathways become tolerant to loss of telomeres in survivors, yet still alert to new DNA damage. We show that Rif1 is responsible for the checkpoint tolerance and proliferation of these survivors, and that is also important for proliferation of cells with a broken chromosome. In contrast, Exo1 drives extensive genomic modifications in survivors. Thus, the conserved proteins Rif1 and Exo1 are critical for survival and evolution of cells with lost telomeres.
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Affiliation(s)
- Yuan Xue
- Newcastle University, Institute for Cell and Molecular Biosciences Institute for Cell and Molecular Biosciences (ICaMB) Newcastle upon Tyne UK
| | - Marcus E. Marvin
- Department of Genetics, Centre for Genetic Architecture of Complex Traits University of Leicester Leicester UK
| | - Iglika G. Ivanova
- Newcastle University, Institute for Cell and Molecular Biosciences Institute for Cell and Molecular Biosciences (ICaMB) Newcastle upon Tyne UK
| | - David Lydall
- Newcastle University, Institute for Cell and Molecular Biosciences Institute for Cell and Molecular Biosciences (ICaMB) Newcastle upon Tyne UK
| | - Edward J. Louis
- Department of Genetics, Centre for Genetic Architecture of Complex Traits University of Leicester Leicester UK
| | - Laura Maringele
- Newcastle University, Institute for Cell and Molecular Biosciences Institute for Cell and Molecular Biosciences (ICaMB) Newcastle upon Tyne UK
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20
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DNA Damage Response in Hematopoietic Stem Cell Ageing. GENOMICS PROTEOMICS & BIOINFORMATICS 2016; 14:147-154. [PMID: 27221660 PMCID: PMC4936660 DOI: 10.1016/j.gpb.2016.04.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 04/20/2016] [Accepted: 04/24/2016] [Indexed: 12/30/2022]
Abstract
Maintenance of tissue-specific stem cells is vital for organ homeostasis and organismal longevity. Hematopoietic stem cells (HSCs) are the most primitive cell type in the hematopoietic system. They divide asymmetrically and give rise to daughter cells with HSC identity (self-renewal) and progenitor progenies (differentiation), which further proliferate and differentiate into full hematopoietic lineages. Mammalian ageing process is accompanied with abnormalities in the HSC self-renewal and differentiation. Transcriptional changes and epigenetic modulations have been implicated as the key regulators in HSC ageing process. The DNA damage response (DDR) in the cells involves an orchestrated signaling pathway, consisting of cell cycle regulation, cell death and senescence, transcriptional regulation, as well as chromatin remodeling. Recent studies employing DNA repair-deficient mouse models indicate that DDR could intrinsically and extrinsically regulate HSC maintenance and play important roles in tissue homeostasis of the hematopoietic system. In this review, we summarize the current understanding of how the DDR determines the HSC fates and finally contributes to organismal ageing.
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21
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Avila AI, Illing A, Becker F, Maerz LD, Morita Y, Philipp M, Burkhalter MD. Xpg limits the expansion of haematopoietic stem and progenitor cells after ionising radiation. Nucleic Acids Res 2016; 44:6252-61. [PMID: 27137888 PMCID: PMC5291257 DOI: 10.1093/nar/gkw376] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 04/25/2016] [Indexed: 12/17/2022] Open
Abstract
Reduced capacity of genome maintenance represents a problem for any organism, potentially causing premature death, carcinogenesis, or accelerated ageing. Strikingly though, loss of certain genome stability factors can be beneficial, especially for the maintenance of tissue stem cells of the intestine and the haematopoietic system. We therefore screened for genome stability factors negatively impacting maintenance of haematopoietic stem cells (HSC) in the context of ionising radiation (IR). We found that in vivo knock down of Xeroderma pigmentosum, complementation group G (Xpg) causes elevation of HSC numbers after IR treatment, while numbers of haematopoietic progenitors are elevated to a lesser extent. IR rapidly induces Xpg both on mRNA and on protein level. Prevention of this induction does not influence activation of the checkpoint cascade, yet attenuates late checkpoint steps such as induction of p21 and Noxa. This causes a leaky cell cycle arrest and lower levels of apoptosis, both contributing to increased colony formation and transformation rates. Xpg thus helps to adequately induce DNA damage responses after IR, thereby keeping the expansion of damaged cells under control. This represents a new function of Xpg in the response to IR, in addition to its well-characterized role in nucleotide excision repair.
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Affiliation(s)
- Alush I Avila
- Leibniz Institute on Aging, Fritz Lipmann Institute, 07745 Jena, Germany
| | - Anett Illing
- Department of Internal Medicine I, Ulm University, 89081 Ulm, Germany
| | - Friedrich Becker
- Leibniz Institute on Aging, Fritz Lipmann Institute, 07745 Jena, Germany
| | - Lars D Maerz
- Institute for Biochemistry and Molecular Biology, Ulm University, 89081 Ulm, Germany
| | - Yohei Morita
- Leibniz Institute on Aging, Fritz Lipmann Institute, 07745 Jena, Germany
| | - Melanie Philipp
- Institute for Biochemistry and Molecular Biology, Ulm University, 89081 Ulm, Germany
| | - Martin D Burkhalter
- Leibniz Institute on Aging, Fritz Lipmann Institute, 07745 Jena, Germany Institute for Biochemistry and Molecular Biology, Ulm University, 89081 Ulm, Germany
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22
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Lenart P, Krejci L. Reprint of "DNA, the central molecule of aging". Mutat Res 2016; 788:25-31. [PMID: 27133220 DOI: 10.1016/j.mrfmmm.2016.04.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 01/16/2016] [Accepted: 01/30/2016] [Indexed: 01/05/2023]
Abstract
Understanding the molecular mechanism of aging could have enormous medical implications. Despite a century of research, however, there is no universally accepted theory regarding the molecular basis of aging. On the other hand, there is plentiful evidence suggesting that DNA constitutes the central molecule in this process. Here, we review the roles of chromatin structure, DNA damage, and shortening of telomeres in aging and propose a hypothesis for how their interplay leads to aging phenotypes.
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Affiliation(s)
- Peter Lenart
- Department of Biology, Masaryk University, Brno, Czech Republic
| | - Lumir Krejci
- Department of Biology, Masaryk University, Brno, Czech Republic; International Clinical Research Center, Center for Biomolecular and Cellular Engineering, St. Anne's University Hospital Brno, Brno, Czech Republic; National Centre for Biomolecular Research, Masaryk University, Brno, Czech Republic.
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23
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DNA, the central molecule of aging. Mutat Res 2016; 786:1-7. [PMID: 26871429 DOI: 10.1016/j.mrfmmm.2016.01.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 01/16/2016] [Accepted: 01/30/2016] [Indexed: 02/07/2023]
Abstract
Understanding the molecular mechanism of aging could have enormous medical implications. Despite a century of research, however, there is no universally accepted theory regarding the molecular basis of aging. On the other hand, there is plentiful evidence suggesting that DNA constitutes the central molecule in this process. Here, we review the roles of chromatin structure, DNA damage, and shortening of telomeres in aging and propose a hypothesis for how their interplay leads to aging phenotypes.
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24
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Parameswaran B, Chiang HC, Lu Y, Coates J, Deng CX, Baer R, Lin HK, Li R, Paull TT, Hu Y. Damage-induced BRCA1 phosphorylation by Chk2 contributes to the timing of end resection. Cell Cycle 2015; 14:437-48. [PMID: 25659039 DOI: 10.4161/15384101.2014.972901] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The BRCA1 tumor suppressor plays an important role in homologous recombination (HR)-mediated DNA double-strand-break (DSB) repair. BRCA1 is phosphorylated by Chk2 kinase upon γ-irradiation, but the role of Chk2 phosphorylation is not understood. Here, we report that abrogation of Chk2 phosphorylation on BRCA1 delays end resection and the dispersion of BRCA1 from DSBs but does not affect the assembly of Mre11/Rad50/NBS1 (MRN) and CtIP at DSBs. Moreover, we show that BRCA1 is ubiquitinated by SCF(Skp2) and that abrogation of Chk2 phosphorylation impairs its ubiquitination. Our study suggests that BRCA1 is more than a scaffold protein to assemble HR repair proteins at DSBs, but that Chk2 phosphorylation of BRCA1 also serves as a built-in clock for HR repair of DSBs. BRCA1 is known to inhibit Mre11 nuclease activity. SCF(Skp2) activity appears at late G1 and peaks at S/G2, and is known to ubiquitinate phosphodegron motifs. The removal of BRCA1 from DSBs by SCF(Skp2)-mediated degradation terminates BRCA1-mediated inhibition of Mre11 nuclease activity, allowing for end resection and restricting the initiation of HR to the S/G2 phases of the cell cycle.
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Affiliation(s)
- Balaji Parameswaran
- a Department of Molecular Medicine ; University of Texas Health Science Center at San Antonio ; San Antonio , TX USA
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25
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Fission Yeast Exo1 and Rqh1-Dna2 Redundantly Contribute to Resection of Uncapped Telomeres. PLoS One 2015; 10:e0140456. [PMID: 26465752 PMCID: PMC4605587 DOI: 10.1371/journal.pone.0140456] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 09/25/2015] [Indexed: 01/01/2023] Open
Abstract
The uncapping of telomeres induces a DNA damage response. In Schizosaccharomyces pombe, deletion of pot1+ causes telomere uncapping and rapid telomere resection, resulting in chromosome fusion. Using the nmt-pot1-aid strain, we previously reported that Pot1 shut-off causes telomere loss and chromosome fusion in S. pombe. However, the factors responsible for the resection of uncapped telomeres remain unknown. In this study, we investigated these factors and found that concomitant deletion of rqh1+ and exo1+ alleviated the loss of telomeres following Pot1 shut-off, suggesting that Rqh1 and Exo1 are redundantly involved in the resection of uncapped telomeres. We also investigated the role of Rqh1 helicase activity and found it to be essential for the resection of uncapped telomeres. Moreover, we found that Dna2 and Exo1 function redundantly in the resection of uncapped telomeres. Taken together, these results suggest that Exo1 and Rqh1-Dna2 redundantly contribute to the resection of uncapped telomeres. Therefore, our results demonstrate that nmt-pot1-aid is an important model strain to study the role of helicases and nucleases in the resection of uncapped telomeres and to improve our understanding of DNA double-strand break repair.
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Managing Single-Stranded DNA during Replication Stress in Fission Yeast. Biomolecules 2015; 5:2123-39. [PMID: 26393661 PMCID: PMC4598791 DOI: 10.3390/biom5032123] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 08/28/2015] [Accepted: 09/01/2015] [Indexed: 01/27/2023] Open
Abstract
Replication fork stalling generates a variety of responses, most of which cause an increase in single-stranded DNA. ssDNA is a primary signal of replication distress that activates cellular checkpoints. It is also a potential source of genome instability and a substrate for mutation and recombination. Therefore, managing ssDNA levels is crucial to chromosome integrity. Limited ssDNA accumulation occurs in wild-type cells under stress. In contrast, cells lacking the replication checkpoint cannot arrest forks properly and accumulate large amounts of ssDNA. This likely occurs when the replication fork polymerase and helicase units are uncoupled. Some cells with mutations in the replication helicase (mcm-ts) mimic checkpoint-deficient cells, and accumulate extensive areas of ssDNA to trigger the G2-checkpoint. Another category of helicase mutant (mcm4-degron) causes fork stalling in early S-phase due to immediate loss of helicase function. Intriguingly, cells realize that ssDNA is present, but fail to detect that they accumulate ssDNA, and continue to divide. Thus, the cellular response to replication stalling depends on checkpoint activity and the time that replication stress occurs in S-phase. In this review we describe the signs, signals, and symptoms of replication arrest from an ssDNA perspective. We explore the possible mechanisms for these effects. We also advise the need for caution when detecting and interpreting data related to the accumulation of ssDNA.
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Burkhalter MD, Rudolph KL, Sperka T. Genome instability of ageing stem cells--Induction and defence mechanisms. Ageing Res Rev 2015; 23:29-36. [PMID: 25668152 PMCID: PMC4504031 DOI: 10.1016/j.arr.2015.01.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/28/2015] [Accepted: 01/30/2015] [Indexed: 01/25/2023]
Abstract
Stem cell function is declining with increasing age. DNA lesions and mutations accumulate in ageing stem cells. Inability to repair DNA can lead to premature depletion of stem cell pools. Checkpoint function preserves genomic integrity at young age. Enforced checkpoint induction contributes to stem cell ageing.
The mammalian organism is comprised of tissue types with varying degrees of self-renewal and regenerative capacity. In most organs self-renewing tissue-specific stem and progenitor cells contribute to organ maintenance, and it is vital to maintain a functional stem cell pool to preserve organ homeostasis. Various conditions like tissue injury, stress responses, and regeneration challenge the stem cell pool to re-establish homeostasis (Fig. 1). However, with increasing age the functionality of adult stem cells declines and genomic mutations accumulate. These defects affect different cellular response pathways and lead to impairments in regeneration, stress tolerance, and organ function as well as to an increased risk for the development of ageing associated diseases and cancer. Maintenance of the genome appears to be of utmost importance to preserve stem cell function and to reduce the risk of ageing associated dysfunctions and pathologies. In this review, we discuss the causal link between stem cell dysfunction and DNA damage accrual, different strategies how stem cells maintain genome integrity, and how these processes are affected during ageing.
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Longo VD, Antebi A, Bartke A, Barzilai N, Brown‐Borg HM, Caruso C, Curiel TJ, Cabo R, Franceschi C, Gems D, Ingram DK, Johnson TE, Kennedy BK, Kenyon C, Klein S, Kopchick JJ, Lepperdinger G, Madeo F, Mirisola MG, Mitchell JR, Passarino G, Rudolph KL, Sedivy JM, Shadel GS, Sinclair DA, Spindler SR, Suh Y, Vijg J, Vinciguerra M, Fontana L. Interventions to Slow Aging in Humans: Are We Ready? Aging Cell 2015; 14:497-510. [PMID: 25902704 PMCID: PMC4531065 DOI: 10.1111/acel.12338] [Citation(s) in RCA: 364] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2015] [Indexed: 12/17/2022] Open
Abstract
The workshop entitled ‘Interventions to Slow Aging in Humans: Are We Ready?’ was held in Erice, Italy, on October 8–13, 2013, to bring together leading experts in the biology and genetics of aging and obtain a consensus related to the discovery and development of safe interventions to slow aging and increase healthy lifespan in humans. There was consensus that there is sufficient evidence that aging interventions will delay and prevent disease onset for many chronic conditions of adult and old age. Essential pathways have been identified, and behavioral, dietary, and pharmacologic approaches have emerged. Although many gene targets and drugs were discussed and there was not complete consensus about all interventions, the participants selected a subset of the most promising strategies that could be tested in humans for their effects on healthspan. These were: (i) dietary interventions mimicking chronic dietary restriction (periodic fasting mimicking diets, protein restriction, etc.); (ii) drugs that inhibit the growth hormone/IGF-I axis; (iii) drugs that inhibit the mTOR–S6K pathway; or (iv) drugs that activate AMPK or specific sirtuins. These choices were based in part on consistent evidence for the pro-longevity effects and ability of these interventions to prevent or delay multiple age-related diseases and improve healthspan in simple model organisms and rodents and their potential to be safe and effective in extending human healthspan. The authors of this manuscript were speakers and discussants invited to the workshop. The following summary highlights the major points addressed and the conclusions of the meeting.
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Martínez P, Blasco MA. Replicating through telomeres: a means to an end. Trends Biochem Sci 2015; 40:504-15. [PMID: 26188776 DOI: 10.1016/j.tibs.2015.06.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/08/2015] [Accepted: 06/12/2015] [Indexed: 02/07/2023]
Abstract
Proper replication of the telomeric DNA at chromosome ends is critical for preserving genome integrity. Yet, telomeres present challenges for the replication machinery, such as their repetitive and heterochromatic nature and their potential to form non-Watson-Crick structures as well as the fact that they are transcribed. Numerous telomere-bound proteins are required to facilitate progression of the replication fork throughout telomeric DNA. In particular, shelterin plays crucial functions in telomere length regulation, protection of telomeres from nuclease degradation, control of DNA damage response at telomeres, and the recruitment of associated factors required for telomere DNA processing and replication. In this review we discuss the recently uncovered functions of mammalian telomere-specific and telomere-associated proteins that facilitate proper telomere replication.
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Affiliation(s)
- Paula Martínez
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Research Centre (CNIO), Madrid E-28029, Spain
| | - Maria A Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Research Centre (CNIO), Madrid E-28029, Spain.
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Chen X, Kim IK, Honaker Y, Paudyal SC, Koh WK, Sparks M, Li S, Piwnica-Worms H, Ellenberger T, You Z. 14-3-3 proteins restrain the Exo1 nuclease to prevent overresection. J Biol Chem 2015; 290:12300-12. [PMID: 25833945 PMCID: PMC4424361 DOI: 10.1074/jbc.m115.644005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 03/31/2015] [Indexed: 11/06/2022] Open
Abstract
The DNA end resection process dictates the cellular response to DNA double strand break damage and is essential for genome maintenance. Although insufficient DNA resection hinders homology-directed repair and ATR (ataxia telangiectasia and Rad3 related)-dependent checkpoint activation, overresection produces excessive single-stranded DNA that could lead to genomic instability. However, the mechanisms controlling DNA end resection are poorly understood. Here we show that the major resection nuclease Exo1 is regulated both positively and negatively by protein-protein interactions to ensure a proper level of DNA resection. We have shown previously that the sliding DNA clamp proliferating cell nuclear antigen (PCNA) associates with the C-terminal domain of Exo1 and promotes Exo1 damage association and DNA resection. In this report, we show that 14-3-3 proteins interact with a central region of Exo1 and negatively regulate Exo1 damage recruitment and subsequent resection. 14-3-3s limit Exo1 damage association, at least in part, by suppressing its association with PCNA. Disruption of the Exo1 interaction with 14-3-3 proteins results in elevated sensitivity of cells to DNA damage. Unlike Exo1, the Dna2 resection pathway is apparently not regulated by PCNA and 14-3-3s. Our results provide critical insights into the mechanism and regulation of the DNA end resection process and may have implications for cancer treatment.
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Affiliation(s)
- Xiaoqing Chen
- From the Departments of Cell Biology and Physiology and
| | - In-Kwon Kim
- Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110 and
| | - Yuchi Honaker
- From the Departments of Cell Biology and Physiology and
| | | | - Won Kyun Koh
- From the Departments of Cell Biology and Physiology and
| | | | - Shan Li
- From the Departments of Cell Biology and Physiology and
| | - Helen Piwnica-Worms
- From the Departments of Cell Biology and Physiology and the Department of Cancer Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77230
| | - Tom Ellenberger
- Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110 and
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Liu JP. Molecular mechanisms of ageing and related diseases. Clin Exp Pharmacol Physiol 2015; 41:445-58. [PMID: 24798238 DOI: 10.1111/1440-1681.12247] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Revised: 04/07/2014] [Accepted: 04/24/2014] [Indexed: 11/29/2022]
Abstract
Human and other multicellular life species age, and ageing processes become dominant during the late phase of life. Recent studies challenge this dogma, suggesting that ageing does not occur in some animal species. In mammals, cell replicative senescence occurs as early as before birth (i.e. in embryos) under physiological conditions. How the molecular machinery operates and why ageing cells dominate under some circumstances are intriguing questions. Recent studies show that cell ageing involves extensive cellular remodelling, including telomere attrition, heterochromatin formation, endoplasmic reticulum stress, mitochondrial disorders and lysosome processing organelles and chromatins. This article provides an update on the molecular mechanisms underlying the ageing of various cell types, the newly described developmental and programmed replicative senescence and the critical roles of cellular organelles and effectors in Parkinson's disease, diabetes, hypertension and dyskeratosis congenita.
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Affiliation(s)
- Jun-Ping Liu
- Institute of Ageing Research, School of Medicine, Hangzhou Normal University, Zhejiang, China; Department of Immunology, Monash University Central Clinical School, Prahran, Victoria, Australia; Department of Genetics, University of Melbourne, Melbourne, Victoria, Australia
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Tao S, Tang D, Morita Y, Sperka T, Omrani O, Lechel A, Sakk V, Kraus J, Kestler HA, Kühl M, Rudolph KL. Wnt activity and basal niche position sensitize intestinal stem and progenitor cells to DNA damage. EMBO J 2015; 34:624-40. [PMID: 25609789 PMCID: PMC4365032 DOI: 10.15252/embj.201490700] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Aging and carcinogenesis coincide with the accumulation of DNA damage and mutations in stem and progenitor cells. Molecular mechanisms that influence responses of stem and progenitor cells to DNA damage remain to be delineated. Here, we show that niche positioning and Wnt signaling activity modulate the sensitivity of intestinal stem and progenitor cells (ISPCs) to DNA damage. ISPCs at the crypt bottom with high Wnt/β-catenin activity are more sensitive to DNA damage compared to ISPCs in position 4 with low Wnt activity. These differences are not induced by differences in cell cycle activity but relate to DNA damage-dependent activation of Wnt signaling, which in turn amplifies DNA damage checkpoint activation. The study shows that instructed enhancement of Wnt signaling increases radio-sensitivity of ISPCs, while inhibition of Wnt signaling decreases it. These results provide a proof of concept that cell intrinsic levels of Wnt signaling modulate the sensitivity of ISPCs to DNA damage and heterogeneity in Wnt activation in the stem cell niche contributes to the selection of ISPCs in the context of DNA damage.
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Affiliation(s)
- Si Tao
- Leibniz Institute for Age Research - Fritz Lipmann Institute e.V. (FLI), Jena, Germany Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany International Graduate School in Molecular Medicine Ulm, Ulm University, Ulm, Germany
| | - Duozhuang Tang
- Leibniz Institute for Age Research - Fritz Lipmann Institute e.V. (FLI), Jena, Germany
| | - Yohei Morita
- Leibniz Institute for Age Research - Fritz Lipmann Institute e.V. (FLI), Jena, Germany
| | - Tobias Sperka
- Leibniz Institute for Age Research - Fritz Lipmann Institute e.V. (FLI), Jena, Germany
| | - Omid Omrani
- Leibniz Institute for Age Research - Fritz Lipmann Institute e.V. (FLI), Jena, Germany
| | - André Lechel
- Cooperation Group between the Leibniz Institute for Age Research, Ulm University, Ulm, Germany
| | - Vadim Sakk
- Cooperation Group between the Leibniz Institute for Age Research, Ulm University, Ulm, Germany
| | - Johann Kraus
- Medical Systems Biology Unit, Ulm University, Ulm, Germany
| | - Hans A Kestler
- Leibniz Institute for Age Research - Fritz Lipmann Institute e.V. (FLI), Jena, Germany Medical Systems Biology Unit, Ulm University, Ulm, Germany
| | - Michael Kühl
- Institute of Biochemistry and Molecular Biology, Ulm University, Ulm, Germany
| | - Karl Lenhard Rudolph
- Leibniz Institute for Age Research - Fritz Lipmann Institute e.V. (FLI), Jena, Germany Research Group on Stem Cell Aging, Jena University Hospital (UKJ), Jena, Germany
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Derboven E, Ekker H, Kusenda B, Bulankova P, Riha K. Role of STN1 and DNA polymerase α in telomere stability and genome-wide replication in Arabidopsis. PLoS Genet 2014; 10:e1004682. [PMID: 25299252 PMCID: PMC4191939 DOI: 10.1371/journal.pgen.1004682] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 08/19/2014] [Indexed: 11/18/2022] Open
Abstract
The CST (Cdc13/CTC1-STN1-TEN1) complex was proposed to have evolved kingdom specific roles in telomere capping and replication. To shed light on its evolutionary conserved function, we examined the effect of STN1 dysfunction on telomere structure in plants. STN1 inactivation in Arabidopsis leads to a progressive loss of telomeric DNA and the onset of telomeric defects depends on the initial telomere size. While EXO1 aggravates defects associated with STN1 dysfunction, it does not contribute to the formation of long G-overhangs. Instead, these G-overhangs arise, at least partially, from telomerase-mediated telomere extension indicating a deficiency in C-strand fill-in synthesis. Analysis of hypomorphic DNA polymerase α mutants revealed that the impaired function of a general replication factor mimics the telomeric defects associated with CST dysfunction. Furthermore, we show that STN1-deficiency hinders re-replication of heterochromatic regions to a similar extent as polymerase α mutations. This comparative analysis of stn1 and pol α mutants suggests that STN1 plays a genome-wide role in DNA replication and that chromosome-end deprotection in stn1 mutants may represent a manifestation of aberrant replication through telomeres. Telomeres form an elaborate nucleoprotein structure that may represent an obstacle for replication machinery and renders this region prone to fork stalling. CST is an evolutionary conserved complex that was originally discovered to specifically act at telomeres. Interestingly, the function of CST seems to have diverged in the course of evolution; in yeast it is required for telomere protection, while in mammals it was proposed to facilitate replication through telomeres. In plants, inactivation of CST leads to telomere deprotection and genome instability. Here we show that the telomere deprotection in Arabidopsis deficient in STN1, one of the CST components, is consistent with defects in telomere replication and that STN1 phenotypes can be partially phenocopied by an impairment of a general replication factor, DNA polymerase α. In addition, we provide evidence that STN1 facilitates re-replication at non-telomeric loci. This suggests a more general role of CST in genome maintenance and further infers that its seemingly specific function(s) in telomere protection may rather represent unique requirements for efficient replication of telomeric DNA.
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Affiliation(s)
- Elisa Derboven
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna, Austria
| | - Heinz Ekker
- Campus Science Support Facilities, Next Generation Sequencing Facility, Vienna, Austria
| | - Branislav Kusenda
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna, Austria
| | - Petra Bulankova
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna, Austria
| | - Karel Riha
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna, Austria
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- * E-mail:
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García‐Beccaria M, Martínez P, Flores JM, Blasco MA. In vivo role of checkpoint kinase 2 in signaling telomere dysfunction. Aging Cell 2014; 13:810-6. [PMID: 24920220 PMCID: PMC4331747 DOI: 10.1111/acel.12237] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2014] [Indexed: 01/01/2023] Open
Abstract
Checkpoint kinase 2 (CHK2) is a downstream effector of the DNA damage response (DDR). Dysfunctional telomeres, either owing to critical shortening or disruption of the shelterin complex, activate a DDR, which eventually results in cell cycle arrest, senescence and/or apoptosis. Successive generations of telomerase-deficient (Terc) mice show accelerated aging and shorter lifespan due to tissue atrophy and impaired organ regeneration associated to progressive telomere shortening. In contrast, mice deficient for the shelterin component TRF1 in stratified epithelia show a rapid and massive induction of DDR, leading to perinatal lethality and severe skin defects. In both mouse models, p53 deficiency can rescue survival. Here, we set to address the role of CHK2 in signaling telomere dysfunction in both mouse models. To this end, we generated mice doubly deficient for Chk2 and either Terc (Chk2−/−Terc−/−) or Trf1 (Trf1Δ/ΔK5Cre Chk2−/−). We show that Chk2 deletion improves Terc-associated phenotypes, including lifespan and age-associated pathologies. Similarly, Chk2 deficiency partially rescues perinatal mortality and attenuates degenerative pathologies of Trf1Δ/ΔK5Cre mice. In both cases, we show that the effects are mediated by a significant attenuation of p53/p21 signaling pathway. Our results represent the first demonstration of a role for CHK2 in the in vivo signaling of dysfunctional telomeres.
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Affiliation(s)
- María García‐Beccaria
- Molecular Oncology Program Telomeres and Telomerase Group Spanish National Cancer Research Centre (CNIO) Madrid E‐28029Spain
| | - Paula Martínez
- Molecular Oncology Program Telomeres and Telomerase Group Spanish National Cancer Research Centre (CNIO) Madrid E‐28029Spain
| | - Juana M. Flores
- Animal Surgery and Medicine Department Faculty of Veterinary Science Complutense University of Madrid Madrid E‐28040Spain
| | - Maria A. Blasco
- Molecular Oncology Program Telomeres and Telomerase Group Spanish National Cancer Research Centre (CNIO) Madrid E‐28029Spain
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Missios P, Zhou Y, Guachalla LM, von Figura G, Wegner A, Chakkarappan SR, Binz T, Gompf A, Hartleben G, Burkhalter MD, Wulff V, Günes C, Sattler RW, Song Z, Illig T, Klaus S, Böhm BO, Wenz T, Hiller K, Rudolph KL. Glucose substitution prolongs maintenance of energy homeostasis and lifespan of telomere dysfunctional mice. Nat Commun 2014; 5:4924. [PMID: 25233189 PMCID: PMC4199114 DOI: 10.1038/ncomms5924] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 08/06/2014] [Indexed: 12/26/2022] Open
Abstract
DNA damage and telomere dysfunction shorten organismal lifespan. Here we show that oral glucose administration at advanced age increases health and lifespan of telomere dysfunctional mice. The study reveals that energy consumption increases in telomere dysfunctional cells resulting in enhanced glucose metabolism both in glycolysis and in the tricarboxylic acid cycle at organismal level. In ageing telomere dysfunctional mice, normal diet provides insufficient amounts of glucose thus leading to impaired energy homeostasis, catabolism, suppression of IGF-1/mTOR signalling, suppression of mitochondrial biogenesis and tissue atrophy. A glucose-enriched diet reverts these defects by activating glycolysis, mitochondrial biogenesis and oxidative glucose metabolism. The beneficial effects of glucose substitution on mitochondrial function and glucose metabolism are blocked by mTOR inhibition but mimicked by IGF-1 application. Together, these results provide the first experimental evidence that telomere dysfunction enhances the requirement of glucose substitution for the maintenance of energy homeostasis and IGF-1/mTOR-dependent mitochondrial biogenesis in ageing tissues. Shortened telomeres and reduced mitochondrial biogenesis are cellular hallmarks of ageing. Here, Missios et al. show that old mice with telomere dysfunction have an increased energetic demand that cannot be met unless mice are fed a glucose-rich diet, which improves energy metabolism and extends lifespan.
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Affiliation(s)
- Pavlos Missios
- Cooperation Group of the Leibniz Institute for Age Research-Fritz-Lipmann-Institute (FLI) Jena with the University of Ulm, 89081 Ulm, Germany
| | - Yuan Zhou
- Cooperation Group of the Leibniz Institute for Age Research-Fritz-Lipmann-Institute (FLI) Jena with the University of Ulm, 89081 Ulm, Germany
| | - Luis Miguel Guachalla
- Cooperation Group of the Leibniz Institute for Age Research-Fritz-Lipmann-Institute (FLI) Jena with the University of Ulm, 89081 Ulm, Germany
| | - Guido von Figura
- Cooperation Group of the Leibniz Institute for Age Research-Fritz-Lipmann-Institute (FLI) Jena with the University of Ulm, 89081 Ulm, Germany
| | - Andre Wegner
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, avenue des Hauts-Fourneaux, Esch-Belval L-4362, Luxembourg
| | - Sundaram Reddy Chakkarappan
- Cooperation Group of the Leibniz Institute for Age Research-Fritz-Lipmann-Institute (FLI) Jena with the University of Ulm, 89081 Ulm, Germany
| | - Tina Binz
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, avenue des Hauts-Fourneaux, Esch-Belval L-4362, Luxembourg
| | - Anne Gompf
- Leibniz Institute for Age Research-Fritz Lipmann Institute (FLI), Beutenbergstr 11, 07745 Jena, Germany
| | - Götz Hartleben
- Leibniz Institute for Age Research-Fritz Lipmann Institute (FLI), Beutenbergstr 11, 07745 Jena, Germany
| | - Martin D Burkhalter
- Leibniz Institute for Age Research-Fritz Lipmann Institute (FLI), Beutenbergstr 11, 07745 Jena, Germany
| | - Veronika Wulff
- Institute for Genetics, Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Zülpicher Street 47A, 50674 Cologne, Germany
| | - Cagatay Günes
- Leibniz Institute for Age Research-Fritz Lipmann Institute (FLI), Beutenbergstr 11, 07745 Jena, Germany
| | - Rui Wang Sattler
- Institute of Epidemiology, Ingolstädter Landstrasse 1, 85764 Munich/Neuherberg, Germany
| | - Zhangfa Song
- Cooperation Group of the Leibniz Institute for Age Research-Fritz-Lipmann-Institute (FLI) Jena with the University of Ulm, 89081 Ulm, Germany
| | - Thomas Illig
- Institute of Epidemiology, Ingolstädter Landstrasse 1, 85764 Munich/Neuherberg, Germany
| | - Susanne Klaus
- German Institute of Human Nutrition, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany
| | - Bernhard O Böhm
- Department of Internal Medicine I, University of Ulm, 89081 Ulm, Germany
| | - Tina Wenz
- Institute for Genetics, Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Zülpicher Street 47A, 50674 Cologne, Germany
| | - Karsten Hiller
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, avenue des Hauts-Fourneaux, Esch-Belval L-4362, Luxembourg
| | - K Lenhard Rudolph
- Leibniz Institute for Age Research-Fritz Lipmann Institute (FLI), Beutenbergstr 11, 07745 Jena, Germany
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Desai A, Gerson S. Exo1 independent DNA mismatch repair involves multiple compensatory nucleases. DNA Repair (Amst) 2014; 21:55-64. [PMID: 25037770 PMCID: PMC5944346 DOI: 10.1016/j.dnarep.2014.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 05/07/2014] [Accepted: 06/11/2014] [Indexed: 11/18/2022]
Abstract
Functional DNA mismatch repair (MMR) is essential for maintaining the fidelity of DNA replication and genetic stability. In hematopoiesis, loss of MMR results in methylating agent resistance and a hematopoietic stem cell (HSC) repopulation defect. Additionally MMR failure is associated with a variety of human malignancies, notably Lynch syndrome. We focus on the 5'→3' exonuclease Exo1, the primary enzyme excising the nicked strand during MMR, preceding polymerase synthesis. We found that nuclease dead Exo1 mutant cells are sensitive to the O6-methylguanine alkylating agent temozolomide when given with the MGMT inactivator, O6benzylguanine (BG). Additionally we used an MMR reporter plasmid to verify that Exo1(mut) MEFs were able to repair G:T base mismatches in vitro. We showed that unlike other MMR deficient mouse models, Exo1(mut) mouse HSC did not gain a competitive survival advantage post temozolomide/BG treatment in vivo. To determine potential nucleases implicated in MMR in the absence of Exo1 nuclease activity, but in the presence of the inactive protein, we performed gene expression analyses of several mammalian nucleases in WT and Exo1(mut) MEFs before and after temozolomide treatment and identified upregulation of Artemis, Fan1, and Mre11. Partial shRNA mediated silencing of each of these in Exo1(mut) cells resulted in decreased MMR capacity and increased resistance to temozolomide/BG. We propose that nuclease function is required for fully functional MMR, but a portfolio of nucleases is able to compensate for loss of Exo1 nuclease activity to maintain proficiency.
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Affiliation(s)
- Amar Desai
- Department of Pharmacology, University Hospitals Seidman Cancer Center and Case Western Reserve University, United States; Division of Hematology/Oncology, Center of Stem Cell and Regenerative Medicine, University Hospitals Seidman Cancer Center and Case Western Reserve University, United States
| | - Stanton Gerson
- Department of Pharmacology, University Hospitals Seidman Cancer Center and Case Western Reserve University, United States; Division of Hematology/Oncology, Center of Stem Cell and Regenerative Medicine, University Hospitals Seidman Cancer Center and Case Western Reserve University, United States; Case Comprehensive Cancer Center, University Hospitals Seidman Cancer Center and Case Western Reserve University, United States.
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37
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Zhang J, Yang R, Zhou D, Rudolph KL, Meng A, Ju Z. Exonuclease 1 is essential for maintaining genomic stability and the proliferative capacity of neural but not hematopoietic stem cells. Stem Cell Res 2014; 12:250-9. [DOI: 10.1016/j.scr.2013.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Revised: 09/26/2013] [Accepted: 11/01/2013] [Indexed: 12/29/2022] Open
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Saha J, Wang M, Cucinotta FA. Investigation of switch from ATM to ATR signaling at the sites of DNA damage induced by low and high LET radiation. DNA Repair (Amst) 2013; 12:1143-51. [PMID: 24238855 DOI: 10.1016/j.dnarep.2013.10.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 09/27/2013] [Accepted: 10/09/2013] [Indexed: 01/11/2023]
Abstract
Upon induction of DNA damage by ionizing radiation (IR), members of the phosphatidylinositol 3-kinase-like kinase family of proteins namely ataxia-telangiectasia mutated (ATM), DNA-PKcs, and ATM- and Rad3-related (ATR) maintain genomic integrity by mounting DNA damage response (DDR). Recent reports suggest that activation of ATM and ATR are oppositely regulated by the length of single stranded overhangs generated during end processing by nucleases at the break sites. These stretches of single stranded overhangs hold the clue for the transition from ATM to ATR signaling at broken DNA ends. We investigated whether differential processing of breaks induced by low and high LET radiation augments the phenomenon of switching from ATM to ATR kinase and hence a concomitant NHEJ to HR transition at the sites of DNA damage. 82-6 human fibroblasts were irradiated with 1 or 2Gy of γ-rays and particle radiation of increasing LET in order to increase the complexity and variability of DNA double strand breaks (DSB) structures. The activation kinetics of ATM and ATR kinases along with their downstream substrates were determined utilizing Western blotting and immunofluorescence techniques. Our data provide evidence of a potential switch from ATM to ATR kinase signaling in cells treated with γ-rays at approximately 2h post irradiation, with induction and completion of resection denoted by Rad51 foci resolution kinetics and observed with a significant decline of phosphorylated ATR kinase 8h after IR. On the other hand, irradiation with high LET 600MeV/u (56)Fe (180keV/μm) and 170MeV/u (28)Si (99keV/μm) particles show a similar Rad51 foci decay kinetics, however, exhibiting prolonged resection, evident by the persistent phosphorylated ATM and ATR kinase until 24h post irradiation. This residual effect, however, was significantly reduced for 250MeV/u (16)O particles of moderate LET (25keV/μm) and absent for γ-rays. Hence, our results support the hypothesis that the transition from ATM to ATR signaling at DNA break sites is extended for longer periods of time, indicated by sustained resection due to the complex type of damage induced, a hallmark of high LET radiation, which may contribute to its increased biological effectiveness.
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Affiliation(s)
- Janapriya Saha
- Division of Space Life Sciences, Universities Space Research Association, 3600 Bay Area Blvd., Houston, TX 77058, USA
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Platt JM, Ryvkin P, Wanat JJ, Donahue G, Ricketts MD, Barrett SP, Waters HJ, Song S, Chavez A, Abdallah KO, Master SR, Wang LS, Johnson FB. Rap1 relocalization contributes to the chromatin-mediated gene expression profile and pace of cell senescence. Genes Dev 2013; 27:1406-20. [PMID: 23756653 DOI: 10.1101/gad.218776.113] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Cellular senescence is accompanied by dramatic changes in chromatin structure and gene expression. Using Saccharomyces cerevisiae mutants lacking telomerase (tlc1Δ) to model senescence, we found that with critical telomere shortening, the telomere-binding protein Rap1 (repressor activator protein 1) relocalizes to the upstream promoter regions of hundreds of new target genes. The set of new Rap1 targets at senescence (NRTS) is preferentially activated at senescence, and experimental manipulations of Rap1 levels indicate that it contributes directly to NRTS activation. A notable subset of NRTS includes the core histone-encoding genes; we found that Rap1 contributes to their repression and that histone protein levels decline at senescence. Rap1 and histones also display a target site-specific antagonism that leads to diminished nucleosome occupancy at the promoters of up-regulated NRTS. This antagonism apparently impacts the rate of senescence because underexpression of Rap1 or overexpression of the core histones delays senescence. Rap1 relocalization is not a simple consequence of lost telomere-binding sites, but rather depends on the Mec1 checkpoint kinase. Rap1 relocalization is thus a novel mechanism connecting DNA damage responses (DDRs) at telomeres to global changes in chromatin and gene expression while driving the pace of senescence.
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Affiliation(s)
- Jesse M Platt
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Mammalian Exo1 encodes both structural and catalytic functions that play distinct roles in essential biological processes. Proc Natl Acad Sci U S A 2013; 110:E2470-9. [PMID: 23754438 DOI: 10.1073/pnas.1308512110] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mammalian Exonuclease 1 (EXO1) is an evolutionarily conserved, multifunctional exonuclease involved in DNA damage repair, replication, immunoglobulin diversity, meiosis, and telomere maintenance. It has been assumed that EXO1 participates in these processes primarily through its exonuclease activity, but recent studies also suggest that EXO1 has a structural function in the assembly of higher-order protein complexes. To dissect the enzymatic and nonenzymatic roles of EXO1 in the different biological processes in vivo, we generated an EXO1-E109K knockin (Exo1(EK)) mouse expressing a stable exonuclease-deficient protein and, for comparison, a fully EXO1-deficient (Exo1(null)) mouse. In contrast to Exo1(null/null) mice, Exo1(EK/EK) mice retained mismatch repair activity and displayed normal class switch recombination and meiosis. However, both Exo1-mutant lines showed defects in DNA damage response including DNA double-strand break repair (DSBR) through DNA end resection, chromosomal stability, and tumor suppression, indicating that the enzymatic function is required for those processes. On a transformation-related protein 53 (Trp53)-null background, the DSBR defect caused by the E109K mutation altered the tumor spectrum but did not affect the overall survival as compared with p53-Exo1(null) mice, whose defects in both DSBR and mismatch repair also compromised survival. The separation of these functions demonstrates the differential requirement for the structural function and nuclease activity of mammalian EXO1 in distinct DNA repair processes and tumorigenesis in vivo.
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Granata M, Panigada D, Galati E, Lazzaro F, Pellicioli A, Plevani P, Muzi-Falconi M. To trim or not to trim: progression and control of DSB end resection. Cell Cycle 2013; 12:1848-60. [PMID: 23708517 DOI: 10.4161/cc.25042] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
DNA double-strand breaks (DSBs) are the most cytotoxic form of DNA damage, since they can lead to genome instability and chromosome rearrangements, which are hallmarks of cancer cells. To face this kind of lesion, eukaryotic cells developed two alternative repair pathways, homologous recombination (HR) and non-homologous end joining (NHEJ). Repair pathway choice is influenced by the cell cycle phase and depends upon the 5'-3' nucleolytic processing of the break ends, since the generation of ssDNA tails strongly stimulates HR and inhibits NHEJ. A large amount of work has elucidated the key components of the DSBs repair machinery and how this crucial process is finely regulated. The emerging view suggests that besides endo/exonucleases and helicases activities required for end resection, molecular barrier factors are specifically loaded in the proximity of the break, where they physically or functionally limit DNA degradation, preventing excessive accumulation of ssDNA, which could be threatening for cell survival.
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Affiliation(s)
- Magda Granata
- Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italia
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42
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Günes C, Rudolph KL. The role of telomeres in stem cells and cancer. Cell 2013; 152:390-3. [PMID: 23374336 DOI: 10.1016/j.cell.2013.01.010] [Citation(s) in RCA: 363] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 12/21/2012] [Accepted: 01/04/2013] [Indexed: 11/17/2022]
Abstract
Telomere shortening impairs proliferation of transformed cells but also leads to cancer initiation by inducing chromosomal instability. Here, we discuss recent developments in our understanding of the role of telomeres in replication stress and how telomerase expression in somatic stem cells may affect genome integrity control and carcinogenesis.
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Affiliation(s)
- Cagatay Günes
- Leibniz Institute for Age Research, Fritz Lipmann Institute, Beutenbergstrasse 11, 07745 Jena, Germany
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Mason PA, Cox LS. The role of DNA exonucleases in protecting genome stability and their impact on ageing. AGE (DORDRECHT, NETHERLANDS) 2012; 34:1317-1340. [PMID: 21948156 PMCID: PMC3528374 DOI: 10.1007/s11357-011-9306-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 08/19/2011] [Indexed: 05/30/2023]
Abstract
Exonucleases are key enzymes involved in many aspects of cellular metabolism and maintenance and are essential to genome stability, acting to cleave DNA from free ends. Exonucleases can act as proof-readers during DNA polymerisation in DNA replication, to remove unusual DNA structures that arise from problems with DNA replication fork progression, and they can be directly involved in repairing damaged DNA. Several exonucleases have been recently discovered, with potentially critical roles in genome stability and ageing. Here we discuss how both intrinsic and extrinsic exonuclease activities contribute to the fidelity of DNA polymerases in DNA replication. The action of exonucleases in processing DNA intermediates during normal and aberrant DNA replication is then assessed, as is the importance of exonucleases in repair of double-strand breaks and interstrand crosslinks. Finally we examine how exonucleases are involved in maintenance of mitochondrial genome stability. Throughout the review, we assess how nuclease mutation or loss predisposes to a range of clinical diseases and particularly ageing.
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Affiliation(s)
- Penelope A. Mason
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Lynne S. Cox
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
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Sperka T, Wang J, Rudolph KL. DNA damage checkpoints in stem cells, ageing and cancer. Nat Rev Mol Cell Biol 2012; 13:579-90. [DOI: 10.1038/nrm3420] [Citation(s) in RCA: 305] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Tümpel S, Rudolph KL. The role of telomere shortening in somatic stem cells and tissue aging: lessons from telomerase model systems. Ann N Y Acad Sci 2012; 1266:28-39. [DOI: 10.1111/j.1749-6632.2012.06547.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Wu P, Takai H, de Lange T. Telomeric 3' overhangs derive from resection by Exo1 and Apollo and fill-in by POT1b-associated CST. Cell 2012; 150:39-52. [PMID: 22748632 DOI: 10.1016/j.cell.2012.05.026] [Citation(s) in RCA: 227] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 03/12/2012] [Accepted: 05/01/2012] [Indexed: 11/18/2022]
Abstract
A 3' overhang is critical for the protection and maintenance of mammalian telomeres, but its synthesis must be regulated to avoid excessive resection of the 5' end, which could cause telomere shortening. How this balance is achieved in mammals has not been resolved. Here, we determine the mechanism for 3' overhang synthesis in mouse cells by evaluating changes in telomeric overhangs throughout the cell cycle and at leading- and lagging-end telomeres. Apollo, a nuclease bound to the shelterin subunit TRF2, initiates formation of the 3' overhang at leading-, but not lagging-end telomeres. Hyperresection by Apollo is blocked at both ends by the shelterin protein POT1b. Exo1 extensively resects both telomere ends, generating transient long 3' overhangs in S/G2. CST/AAF, a DNA polα.primase accessory factor, binds POT1b and shortens the extended overhangs produced by Exo1, likely through fill-in synthesis. 3' overhang formation is thus a multistep, shelterin-controlled process, ensuring functional telomeric overhangs at chromosome ends.
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Affiliation(s)
- Peng Wu
- Laboratory for Cell Biology and Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
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Thompson LH. Recognition, signaling, and repair of DNA double-strand breaks produced by ionizing radiation in mammalian cells: the molecular choreography. Mutat Res 2012; 751:158-246. [PMID: 22743550 DOI: 10.1016/j.mrrev.2012.06.002] [Citation(s) in RCA: 261] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 06/09/2012] [Accepted: 06/16/2012] [Indexed: 12/15/2022]
Abstract
The faithful maintenance of chromosome continuity in human cells during DNA replication and repair is critical for preventing the conversion of normal diploid cells to an oncogenic state. The evolution of higher eukaryotic cells endowed them with a large genetic investment in the molecular machinery that ensures chromosome stability. In mammalian and other vertebrate cells, the elimination of double-strand breaks with minimal nucleotide sequence change involves the spatiotemporal orchestration of a seemingly endless number of proteins ranging in their action from the nucleotide level to nucleosome organization and chromosome architecture. DNA DSBs trigger a myriad of post-translational modifications that alter catalytic activities and the specificity of protein interactions: phosphorylation, acetylation, methylation, ubiquitylation, and SUMOylation, followed by the reversal of these changes as repair is completed. "Superfluous" protein recruitment to damage sites, functional redundancy, and alternative pathways ensure that DSB repair is extremely efficient, both quantitatively and qualitatively. This review strives to integrate the information about the molecular mechanisms of DSB repair that has emerged over the last two decades with a focus on DSBs produced by the prototype agent ionizing radiation (IR). The exponential growth of molecular studies, heavily driven by RNA knockdown technology, now reveals an outline of how many key protein players in genome stability and cancer biology perform their interwoven tasks, e.g. ATM, ATR, DNA-PK, Chk1, Chk2, PARP1/2/3, 53BP1, BRCA1, BRCA2, BLM, RAD51, and the MRE11-RAD50-NBS1 complex. Thus, the nature of the intricate coordination of repair processes with cell cycle progression is becoming apparent. This review also links molecular abnormalities to cellular pathology as much a possible and provides a framework of temporal relationships.
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Affiliation(s)
- Larry H Thompson
- Biology & Biotechnology Division, L452, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551-0808, United States.
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Wang J, Sun Q, Morita Y, Jiang H, Gross A, Lechel A, Hildner K, Guachalla LM, Gompf A, Hartmann D, Schambach A, Wuestefeld T, Dauch D, Schrezenmeier H, Hofmann WK, Nakauchi H, Ju Z, Kestler HA, Zender L, Rudolph KL. A differentiation checkpoint limits hematopoietic stem cell self-renewal in response to DNA damage. Cell 2012; 148:1001-14. [PMID: 22385964 DOI: 10.1016/j.cell.2012.01.040] [Citation(s) in RCA: 251] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 09/22/2011] [Accepted: 01/25/2012] [Indexed: 01/19/2023]
Abstract
Checkpoints that limit stem cell self-renewal in response to DNA damage can contribute to cancer protection but may also promote tissue aging. Molecular components that control stem cell responses to DNA damage remain to be delineated. Using in vivo RNAi screens, we identified basic leucine zipper transcription factor, ATF-like (BATF) as a major component limiting self-renewal of hematopoietic stem cells (HSCs) in response to telomere dysfunction and γ-irradiation. DNA damage induces BATF in a G-CSF/STAT3-dependent manner resulting in lymphoid differentiation of HSCs. BATF deletion improves HSC self-renewal and function in response to γ-irradiation or telomere shortening but results in accumulation of DNA damage in HSCs. Analysis of bone marrow from patients with myelodysplastic syndrome supports the conclusion that DNA damage-dependent induction of BATF is conserved in human HSCs. Together, these results provide experimental evidence that a BATF-dependent differentiation checkpoint limits self-renewal of HSCs in response to DNA damage.
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Affiliation(s)
- Jianwei Wang
- Institute of Molecular Medicine and Max-Planck-Research Department of Stem Cell Aging, University of Ulm, Ulm, Germany
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Song F, Qureshi AA, Zhang J, Zhan J, Amos CI, Lee JE, Wei Q, Han J. Exonuclease 1 (EXO1) gene variation and melanoma risk. DNA Repair (Amst) 2012; 11:304-9. [PMID: 22230721 DOI: 10.1016/j.dnarep.2011.12.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 11/08/2011] [Accepted: 12/10/2011] [Indexed: 02/01/2023]
Abstract
OBJECTIVE DNA repair pathway genes play an important role in maintaining genomic integrity and protecting against cancer development. This study aimed to identify novel SNPs in the DNA repair-related genes associated with melanoma risk from a genome-wide association study (GWAS). METHODS A total of 8422 SNPs from the 165 DNA repair-related genes were extracted from a GWAS of melanoma risk, including 494 cases and 5628 controls from the Nurses' Health Study (NHS) and the Health Professionals Follow-up Study (HPFS). We further replicated the top SNPs in a GWAS of melanoma risk from the MD Anderson Cancer Center (1804 cases and 1026 controls). RESULTS A total of 3 SNPs with P value <0.001 were selected for in silico replication. One SNP was replicated: rs3902093 [A] in EXO1 promoter region (P(discovery)=6.6 × 10⁻⁴, P(replication)=0.039, P(joint)=2.5 × 10⁻⁴; OR(joint)=0.80, 95% CI: 0.71, 0.90). This SNP was associated with the expression of the EXO1; carriers of the A allele showed lower expression (P=0.002). CONCLUSION Our study found that a promoter region SNP in the editing and processing nucleases gene EXO1 was associated with decreased expression of EXO1 and decreased melanoma risk. Further studies are warranted to validate this association and to investigate the potential mechanisms.
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Affiliation(s)
- Fengju Song
- Department of Epidemiology, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
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Andersen SD, Keijzers G, Rampakakis E, Engels K, Luhn P, El-Shemerly M, Nielsen FC, Du Y, May A, Bohr VA, Ferrari S, Zannis-Hadjopoulos M, Fu H, Rasmussen LJ. 14-3-3 checkpoint regulatory proteins interact specifically with DNA repair protein human exonuclease 1 (hEXO1) via a semi-conserved motif. DNA Repair (Amst) 2012; 11:267-77. [PMID: 22222486 DOI: 10.1016/j.dnarep.2011.11.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Revised: 11/06/2011] [Accepted: 11/30/2011] [Indexed: 12/14/2022]
Abstract
Human exonuclease 1 (hEXO1) acts directly in diverse DNA processing events, including replication, mismatch repair (MMR), and double strand break repair (DSBR), and it was also recently described to function as damage sensor and apoptosis inducer following DNA damage. In contrast, 14-3-3 proteins are regulatory phosphorserine/threonine binding proteins involved in the control of diverse cellular events, including cell cycle checkpoint and apoptosis signaling. hEXO1 is regulated by post-translation Ser/Thr phosphorylation in a yet not fully clarified manner, but evidently three phosphorylation sites are specifically induced by replication inhibition leading to protein ubiquitination and degradation. We demonstrate direct and robust interaction between hEXO1 and six of the seven 14-3-3 isoforms in vitro, suggestive of a novel protein interaction network between DNA repair and cell cycle control. Binding experiments reveal weak affinity of the more selective isoform 14-3-3σ but both 14-3-3 isoforms η and σ significantly stimulate hEXO1 activity, indicating that these regulatory proteins exert a common regulation mode on hEXO1. Results demonstrate that binding involves the phosphorable amino acid S746 in hEXO1 and most likely a second unidentified binding motif. 14-3-3 associations do not appear to directly influence hEXO1 in vitro nuclease activity or in vitro DNA replication initiation. Moreover, specific phosphorylation variants, including hEXO1 S746A, are efficiently imported to the nucleus; to associate with PCNA in distinct replication foci and respond to DNA double strand breaks (DSBs), indicating that 14-3-3 binding does not involve regulating the subcellular distribution of hEXO1. Altogether, these results suggest that association may be related to regulation of hEXO1 availability during the DNA damage response to plausibly prevent extensive DNA resection at the damage site, as supported by recent studies.
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