1
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Fukumoto Y, Hoshino T, Nakayama Y, Ogra Y. The C-terminal tail of Rad17, iVERGE, binds the 9‒1‒1 complex independently of AAA+ ATPase domains to provide another clamp-loader interface. DNA Repair (Amst) 2023; 130:103567. [PMID: 37713925 DOI: 10.1016/j.dnarep.2023.103567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 08/17/2023] [Accepted: 09/03/2023] [Indexed: 09/17/2023]
Abstract
The ATR pathway plays a crucial role in maintaining genome integrity as the major DNA damage checkpoint. It also attracts attention as a therapeutic target in cancer treatment. The Rad17-RFC2-5 complex loads the Rad9-Hus1-Rad1 (9-1-1) DNA clamp complex onto damaged chromatin to activate the ATR pathway. We previously reported that phosphorylation of a polyanionic C-terminal tail of human Rad17, iVERGE, is essential for the interaction between Rad17 and the 9-1-1 complex. However, the molecular mechanism has remained unclear. Here, we show that iVERGE directly interacts with the Hus1 subunit of the 9-1-1 complex through Rad17-S667 phosphorylation independently of the AAA+ ATPase domains. An exogenous iVERGE peptide interacted with the 9-1-1 complex in vivo. The binding conformation of the iVERGE peptide was analyzed by de novo modeling with docking simulation, simulated annealing-molecular dynamics simulation, and the fragment molecular orbital method. The in silico analyses predicted the association of the iVERGE peptide with the hydrophobic and basic patches on the Hus1 protein, and the corresponding Hus1 mutants were deficient in the interaction with the iVERGE peptide in vivo. The iVERGE peptide occupied the same position as the C-terminus of Saccharomyces cerevisiae RAD24 on MEC3. The interaction energy calculation suggested that the Rad17 KYxxL motif and the iVERGE peptide are the primary and secondary interaction surfaces between the Rad17-RFC2-5 and 9-1-1 complexes. Our data reveal a novel molecular interface, iVERGE, between the Rad17-RFC2-5 and 9-1-1 complexes in vertebrates and implicate that Rad17 utilizes two distinct molecular interfaces to regulate the 9-1-1 complex.
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Affiliation(s)
- Yasunori Fukumoto
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan.
| | - Tyuji Hoshino
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan
| | - Yuji Nakayama
- Department of Biochemistry & Molecular Biology, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Yasumitsu Ogra
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan
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2
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Uchida C, Niida H, Sakai S, Iijima K, Kitagawa K, Ohhata T, Shiotani B, Kitagawa M. p130RB2 positively contributes to ATR activation in response to replication stress via the RPA32-ETAA1 axis. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119484. [PMID: 37201767 DOI: 10.1016/j.bbamcr.2023.119484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 03/17/2023] [Accepted: 04/23/2023] [Indexed: 05/20/2023]
Abstract
Ataxia-telangiectasia mutated and Rad3-related (ATR) kinase is a crucial regulator of the cell cycle checkpoint and activated in response to DNA replication stress by two independent pathways via RPA32-ETAA1 and TopBP1. However, the precise activation mechanism of ATR by the RPA32-ETAA1 pathway remains unclear. Here, we show that p130RB2, a member of the retinoblastoma protein family, participates in the pathway under hydroxyurea-induced DNA replication stress. p130RB2 binds to ETAA1, but not TopBP1, and depletion of p130RB2 inhibits the RPA32-ETAA1 interaction under replication stress. Moreover, p130RB2 depletion reduces ATR activation accompanied by phosphorylation of its targets RPA32, Chk1, and ATR itself. It also causes improper re-progression of S phase with retaining single-stranded DNA after cancelation of the stress, which leads to an increase in the anaphase bridge phenotype and a decrease in cell survival. Importantly, restoration of p130RB2 rescued the disrupted phenotypes of p130RB2 knockdown cells. These results suggest positive involvement of p130RB2 in the RPA32-ETAA1-ATR axis and proper re-progression of the cell cycle to maintain genome integrity.
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Affiliation(s)
- Chiharu Uchida
- Advanced Research Facilities & Services, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan.
| | - Hiroyuki Niida
- Department of Molecular Biology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Satoshi Sakai
- Department of Molecular Biology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Kenta Iijima
- Laboratory Animal Facilities & Services, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Kyoko Kitagawa
- Department of Environmental Health, University of Occupational and Environmental Health, Kitakyushu, Fukuoka 807-8555, Japan
| | - Tatsuya Ohhata
- Department of Molecular Biology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | - Bunsyo Shiotani
- Laboratory of Genome Stress Signaling, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045, Japan
| | - Masatoshi Kitagawa
- Department of Molecular Biology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
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3
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Acharya N, Prakash L, Prakash S. Yeast 9-1-1 complex acts as a sliding clamp for DNA synthesis by DNA polymerase ε. J Biol Chem 2023; 299:102727. [PMID: 36410434 PMCID: PMC9791402 DOI: 10.1016/j.jbc.2022.102727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/10/2022] [Accepted: 11/13/2022] [Indexed: 11/21/2022] Open
Abstract
Eukaryotic cells harbor two DNA-binding clamps, proliferating cell nuclear antigen (PCNA), and another clamp commonly referred to as 9-1-1 clamp. In contrast to the essential role of PCNA in DNA replication as a sliding clamp for DNA polymerase (Pol) δ, no such role in DNA synthesis has been identified for the human 9-1-1 clamp or the orthologous yeast 17-3-1 clamp. The only role identified for either the 9-1-1 or 17-3-1 clamp is in the recruitment of signal transduction kinases, which affect the activation of cell cycle checkpoints in response to DNA damage. However, unlike the loading of PCNA by the replication factor C (RFC) clamp loader onto 3'-recessed DNA junctions for processive DNA synthesis by Polδ, the 17-3-1 clamp or the 9-1-1 clamp is loaded by their respective clamp loader Rad24-RFC or RAD17-RFC onto the 5'-recessed DNA junction of replication protein A-coated DNA for the recruitment of signal transduction kinases. Here, we identify a novel role of 17-3-1 clamp as a sliding clamp for DNA synthesis by Polε. We provide evidence that similar to the loading of PCNA by RFC, the 17-3-1 clamp is loaded by the Rad24-RFC clamp loader at the 3'-recessed DNA junction in an ATP-dependent manner. However, unlike PCNA, the 17-3-1 clamp does not enhance the processivity of DNA synthesis by Polε; instead, it greatly increases the catalytic efficiency of Polε for correct nucleotide incorporation. Furthermore, we show that the same PCNA-interacting peptide domain in the polymerase 2 catalytic subunit mediates Polε interaction with the 17-3-1 clamp and with PCNA.
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Affiliation(s)
- Narottam Acharya
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Louise Prakash
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Satya Prakash
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA.
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4
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Majid S, Van Belleghem F, Ploem JP, Wouters A, Blust R, Smeets K. Interactive toxicity of copper and cadmium in regenerating and adult planarians. CHEMOSPHERE 2022; 297:133819. [PMID: 35114265 DOI: 10.1016/j.chemosphere.2022.133819] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 12/31/2021] [Accepted: 01/28/2022] [Indexed: 06/14/2023]
Abstract
In a polluted environment, metals are present as complex mixtures. As a result, organisms are exposed to different metals at the same time, which affects both metal-specific as well as overall toxicity. Detailed information about the molecular mechanisms underlying the adverse effects of combined exposures remains limited in terms of different life stages. In this study, the freshwater planarian Schmidtea mediterranea was used to investigate developmental and physiological responses associated with a combined exposure to Cu and Cd. In addition, the cellular and molecular mechanisms underlying the provoked adverse effects were studied in different exposure scenarios. Mixed exposure resulted in a decline in survival, diverse non-lethal morphological changes, neuroregenerative impairments, altered behaviour and a limited repair capacity. Underlying to these effects, the cellular redox state was altered in all exposure conditions. In adult animals, this led to DNA damage and corresponding transcriptional changes in cell cycle and DNA repair genes. In regenerating animals, changes in hydrogen peroxide and glutathione contents led to regenerative defects. Overall, our results demonstrate that (1) developing organisms are more susceptible to metal exposures, and (2) the toxicity of an individual metal increases significantly in a mixed exposure scenario. These aspects have to be included in current risk assessment strategies.
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Affiliation(s)
- Sanah Majid
- Laboratory of Toxicology, Centre for Environmental Sciences (CMK), Hasselt University, Diepenbeek, 3590, Belgium; Systemic Physiological & Eco-toxicological Research (SPHERE), Department of Biology, University of Antwerp, Groenenborgerlaan, 2020, Belgium
| | - Frank Van Belleghem
- Laboratory of Toxicology, Centre for Environmental Sciences (CMK), Hasselt University, Diepenbeek, 3590, Belgium; Department of Environmental Sciences, Faculty of Science, Open University of the Netherlands, Heerlen, 6419, AT, the Netherlands
| | - Jan-Pieter Ploem
- Laboratory of Toxicology, Centre for Environmental Sciences (CMK), Hasselt University, Diepenbeek, 3590, Belgium
| | - Annelies Wouters
- Laboratory of Toxicology, Centre for Environmental Sciences (CMK), Hasselt University, Diepenbeek, 3590, Belgium
| | - Ronny Blust
- Systemic Physiological & Eco-toxicological Research (SPHERE), Department of Biology, University of Antwerp, Groenenborgerlaan, 2020, Belgium
| | - Karen Smeets
- Laboratory of Toxicology, Centre for Environmental Sciences (CMK), Hasselt University, Diepenbeek, 3590, Belgium.
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5
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Fukumoto Y, Ikeuchi M, Qu L, Hoshino T, Yamaguchi N, Nakayama Y, Ogra Y. Nuclear translocation promotes proteasomal degradation of human Rad17 protein through the N-terminal destruction boxes. J Biol Chem 2021; 297:100831. [PMID: 34174284 PMCID: PMC8318897 DOI: 10.1016/j.jbc.2021.100831] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/17/2021] [Accepted: 05/24/2021] [Indexed: 12/15/2022] Open
Abstract
The ATR pathway is one of the major DNA damage checkpoints, and Rad17 is a DNA-binding protein that is phosphorylated upon DNA damage by ATR kinase. Rad17 recruits the 9-1-1 complex that mediates the checkpoint activation, and proteasomal degradation of Rad17 is important for recovery from the ATR pathway. Here, we identified several Rad17 mutants deficient in nuclear localization and resistant to proteasomal degradation. The nuclear localization signal was identified in the central basic domain of Rad17. Rad17 Δ230–270 and R240A/L243A mutants that were previously postulated to lack the destruction box, a sequence that is recognized by the ubiquitin ligase/anaphase-promoting complex that mediates degradation of Rad17, also showed cytoplasmic localization. Our data indicate that the nuclear translocation of Rad17 is functionally linked to the proteasomal degradation. The ATP-binding activity of Rad17, but not hydrolysis, is essential for the nuclear translocation, and the ATPase domain orchestrates the nuclear translocation, the proteasomal degradation, as well as the interaction with the 9-1-1 complex. The Rad17 mutant that lacked a nuclear localization signal was proficient in the interaction with the 9-1-1 complex, suggesting cytosolic association of Rad17 and the 9-1-1 complex. Finally, we identified two tandem canonical and noncanonical destruction boxes in the N-terminus of Rad17 as the bona fide destruction box, supporting the role of anaphase-promoting complex in the degradation of Rad17. We propose a model in which Rad17 is activated in the cytoplasm for translocation into the nucleus and continuously degraded in the nucleus even in the absence of exogenous DNA damage.
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Affiliation(s)
- Yasunori Fukumoto
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
| | - Masayoshi Ikeuchi
- Department of Biochemistry & Molecular Biology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Liang Qu
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Tyuji Hoshino
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Naoto Yamaguchi
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
| | - Yuji Nakayama
- Department of Biochemistry & Molecular Biology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Yasumitsu Ogra
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan
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6
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van Schendel R, Romeijn R, Buijs H, Tijsterman M. Preservation of lagging strand integrity at sites of stalled replication by Pol α-primase and 9-1-1 complex. SCIENCE ADVANCES 2021; 7:eabf2278. [PMID: 34138739 PMCID: PMC8133754 DOI: 10.1126/sciadv.abf2278] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 03/31/2021] [Indexed: 05/03/2023]
Abstract
During genome duplication, the replication fork encounters a plethora of obstacles in the form of damaged bases, DNA-cross-linked proteins, and secondary structures. How cells protect DNA integrity at sites of stalled replication is currently unknown. Here, by engineering "primase deserts" into the Caenorhabditis elegans genome close to replication-impeding G-quadruplexes, we show that de novo DNA synthesis downstream of the blocked fork suppresses DNA loss. We next identify the pol α-primase complex to limit deletion mutagenesis, a conclusion substantiated by whole-genome analysis of animals carrying mutated POLA2/DIV-1. We subsequently identify a new role for the 9-1-1 checkpoint clamp in protecting Okazaki fragments from resection by EXO1. Together, our results provide a mechanistic model for controlling the fate of replication intermediates at sites of stalled replication.
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Affiliation(s)
- Robin van Schendel
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, Netherlands
| | - Ron Romeijn
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, Netherlands
| | - Helena Buijs
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, Netherlands
| | - Marcel Tijsterman
- Department of Human Genetics, Leiden University Medical Center, Einthovenweg 20, 2333 ZC Leiden, Netherlands.
- Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, Netherlands
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7
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Xu J, Wang G, Gong W, Guo S, Li D, Zhan Q. The noncoding function of NELFA mRNA promotes the development of oesophageal squamous cell carcinoma by regulating the Rad17-RFC2-5 complex. Mol Oncol 2020; 14:611-624. [PMID: 31845510 PMCID: PMC7053240 DOI: 10.1002/1878-0261.12619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 11/27/2019] [Accepted: 12/13/2019] [Indexed: 12/11/2022] Open
Abstract
Recently, RNAs interacting with proteins have been implicated in playing an important role in the occurrence and progression of oesophageal squamous cell carcinoma (ESCC). In this study, we found that NELFA mRNA interacts with Rad17 through a novel noncoding mode in the nucleus and that the aberrant expression of USF2 contributed to the upregulation of Rad17 and NELFA. Subsequent experiments demonstrated that the deletion of NELFA mRNA significantly decreased ESCC proliferation and colony formation in vitro. Moreover, NELFA mRNA knockdown inhibited DNA damage repair and promoted apoptosis. Mechanistic studies indicated that NELFA mRNA regulated the interaction between Rad17 and RFC2‐5, which had a major impact on the phosphorylation of CHK1, CHK2 and BRCA1. NELFA mRNA expression was consistently elevated in ESCC patients and closely related to decreased overall survival. Taken together, our results confirmed the critical role of the noncoding function of NELFA mRNA in ESCC tumorigenesis and indicated that NELFA mRNA can be regarded as a therapeutic target and an independent prognostic indicator in ESCC patients.
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Affiliation(s)
- Jiancheng Xu
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Guangchao Wang
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wei Gong
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Shichao Guo
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Dan Li
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qimin Zhan
- State Key Laboratory of Molecular Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Laboratory of Molecular Oncology, Peking University Cancer Hospital and Institute, Beijing, China
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8
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Human Rad17 C-terminal tail is phosphorylated by concerted action of CK1δ/ε and CK2 to promote interaction with the 9–1–1 complex. Biochem Biophys Res Commun 2019; 517:310-316. [DOI: 10.1016/j.bbrc.2019.07.076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 07/20/2019] [Indexed: 11/20/2022]
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9
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D'Ignazio L, Michel M, Beyer M, Thompson K, Forabosco A, Schlessinger D, Pelosi E. Lhx8 ablation leads to massive autophagy of mouse oocytes associated with DNA damage. Biol Reprod 2019; 98:532-542. [PMID: 29329412 DOI: 10.1093/biolre/iox184] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 01/09/2018] [Indexed: 12/12/2022] Open
Abstract
Following proliferation of oogonia in mammals, great numbers of germ cells are discarded, primarily by apoptosis, while the remainder form primordial follicles (the ovarian reserve) that determine fertility and reproductive lifespan. More massive, rapid, and essentially total loss of oocytes, however, occurs when the transcription factor Lhx8 is ablated-though the cause and mechanism of germ cell loss from the Lhx8-/- ovaries has been unknown. We found that Lhx8-/- ovaries maintain the same number of germ cells throughout embryonic development; rapid decrease in the pool of oocytes starts shortly before birth. The loss results from activation of autophagy, which becomes overwhelming within the first postnatal week, with extracellular matrix proteins filling the space previously occupied by follicles to produce a fibrotic ovary. Associated with this process, as early as a few days before birth, Lhx8-/- oocytes failed to repair DNA damage-which normally occurs when meiosis is initiated during embryonic development; and DNA damage repair genes were downregulated throughout the oocyte short lifespan. Based on gene expression analyses and morphological changes, we propose a model in which lineage-restricted failure of DNA repair triggers germ cell autophagy, causing premature depletion of the ovarian reserve in Lhx8-/- mice.
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Affiliation(s)
- Laura D'Ignazio
- Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Marc Michel
- Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Melissa Beyer
- Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Kassimier Thompson
- Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | | | - David Schlessinger
- Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Emanuele Pelosi
- Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
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10
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Ohashi E, Tsurimoto T. Functions of Multiple Clamp and Clamp-Loader Complexes in Eukaryotic DNA Replication. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1042:135-162. [PMID: 29357057 DOI: 10.1007/978-981-10-6955-0_7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Proliferating cell nuclear antigen (PCNA) and replication factor C (RFC) were identified in the late 1980s as essential factors for replication of simian virus 40 DNA in human cells, by reconstitution of the reaction in vitro. Initially, they were only thought to be involved in the elongation stage of DNA replication. Subsequent studies have demonstrated that PCNA functions as more than a replication factor, through its involvement in multiple protein-protein interactions. PCNA appears as a functional hub on replicating and replicated chromosomal DNA and has an essential role in the maintenance genome integrity in proliferating cells.Eukaryotes have multiple paralogues of sliding clamp, PCNA and its loader, RFC. The PCNA paralogues, RAD9, HUS1, and RAD1 form the heterotrimeric 9-1-1 ring that is similar to the PCNA homotrimeric ring, and the 9-1-1 clamp complex is loaded onto sites of DNA damage by its specific loader RAD17-RFC. This alternative clamp-loader system transmits DNA-damage signals in genomic DNA to the checkpoint-activation network and the DNA-repair apparatus.Another two alternative loader complexes, CTF18-RFC and ELG1-RFC, have roles that are distinguishable from the role of the canonical loader, RFC. CTF18-RFC interacts with one of the replicative DNA polymerases, Polε, and loads PCNA onto leading-strand DNA, and ELG1-RFC unloads PCNA after ligation of lagging-strand DNA. In the progression of S phase, these alternative PCNA loaders maintain appropriate amounts of PCNA on the replicating sister DNAs to ensure that specific enzymes are tethered at specific chromosomal locations.
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Affiliation(s)
- Eiji Ohashi
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Toshiki Tsurimoto
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan.
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11
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Fukumoto Y, Takahashi K, Suzuki N, Ogra Y, Nakayama Y, Yamaguchi N. Casein kinase 2 promotes interaction between Rad17 and the 9-1-1 complex through constitutive phosphorylation of the C-terminal tail of human Rad17. Biochem Biophys Res Commun 2018; 504:380-386. [PMID: 29902452 DOI: 10.1016/j.bbrc.2018.06.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 06/09/2018] [Indexed: 12/23/2022]
Abstract
An interaction between the Rad17-RFC2-5 and 9-1-1 complexes is essential for ATR-Chk1 signaling, which is one of the major DNA damage checkpoints. Recently, we showed that the polyanionic C-terminal tail of human Rad17 and the embedded conserved sequence iVERGE are important for the interaction with 9-1-1 complex. Here, we show that Rad17-S667 in the C-terminal tail is constitutively phosphorylated in vivo in a casein kinase 2-dependent manner, and the phosphorylation is important for 9-1-1 interaction. The serine phosphorylation of Rad17 could be seen in the absence of exogenous genotoxic stress, and was mostly abolished by S667A substitution. Rad17-S667 was also phosphorylated when the C-terminal tail was fused with EGFP, but the phosphorylation was inhibited by two casein kinase 2 inhibitors. Furthermore, interaction between Rad17 and the 9-1-1 complex was inhibited by the casein kinase 2 inhibitor CX-4945/Silmitasertib, and the effect was dependent on the Rad17-S667 residue, indicating that S667 phosphorylation is the only role of casein kinase 2 in the 9-1-1 interaction. Our data raise the possibility that the C-terminal tail of vertebrate Rad17 regulates ATR-Chk1 signaling through multi-site phosphorylation in the iVERGE.
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Affiliation(s)
- Yasunori Fukumoto
- Laboratory of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, 260-8675, Japan.
| | - Kazuaki Takahashi
- Laboratory of Toxicology and Environmental Health, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, 260-8675, Japan
| | - Noriyuki Suzuki
- Laboratory of Toxicology and Environmental Health, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, 260-8675, Japan
| | - Yasumitsu Ogra
- Laboratory of Toxicology and Environmental Health, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, 260-8675, Japan
| | - Yuji Nakayama
- Department of Biochemistry & Molecular Biology, Kyoto Pharmaceutical University, Kyoto, 607-8414, Japan
| | - Naoto Yamaguchi
- Laboratory of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, 260-8675, Japan.
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12
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Fukumoto Y, Nakayama Y, Yamaguchi N. The polyanionic C-terminal tail of human Rad17 regulates interaction with the 9–1–1 complex. Biochem Biophys Res Commun 2017; 490:1147-1153. [DOI: 10.1016/j.bbrc.2017.06.159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 06/27/2017] [Indexed: 02/06/2023]
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13
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Hyttinen JMT, Błasiak J, Niittykoski M, Kinnunen K, Kauppinen A, Salminen A, Kaarniranta K. DNA damage response and autophagy in the degeneration of retinal pigment epithelial cells-Implications for age-related macular degeneration (AMD). Ageing Res Rev 2017; 36:64-77. [PMID: 28351686 DOI: 10.1016/j.arr.2017.03.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 03/23/2017] [Accepted: 03/23/2017] [Indexed: 12/14/2022]
Abstract
In this review we will discuss the links between autophagy, a mechanism involved in the maintenance of cellular homeostasis and controlling cellular waste management, and the DNA damage response (DDR), comprising various mechanisms preserving the integrity and stability of the genome. A reduced autophagy capacity in retinal pigment epithelium has been shown to be connected in the pathogenesis of age-related macular degeneration (AMD), an eye disease. This degenerative disease is a major and increasing cause of vision loss in the elderly in developed countries, primarily due to the profound accumulation of intra- and extracellular waste: lipofuscin and drusen. An abundance of reactive oxygen species is produced in the retina since this tissue has a high oxygen demand and contains mitochondria-rich cells. The retina is exposed to light and it also houses many photoactive molecules. These factors are clearly reflected in both the autophagy and DNA damage rates, and in both nuclear and mitochondrial genomes. It remains to be revealed whether DNA damage and DDR capacity have a more direct role in the development of AMD.
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Affiliation(s)
- Juha M T Hyttinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland.
| | - Janusz Błasiak
- Department of Molecular Genetics, University of Łódź, Pomorska 141/143, 90-236, Łódź, Poland
| | - Minna Niittykoski
- Institute of Biotechnology, Developmental Biology Program, University of Helsinki, P.O. Box 56, FI-00014, Finland
| | - Kati Kinnunen
- Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, FI-70029, Finland
| | - Anu Kauppinen
- School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland
| | - Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 100, FI-70029, Finland
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14
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Lindsey-Boltz LA. Bringing It All Together: Coupling Excision Repair to the DNA Damage Checkpoint. Photochem Photobiol 2016; 93:238-244. [PMID: 27861980 DOI: 10.1111/php.12667] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 09/29/2016] [Indexed: 12/15/2022]
Abstract
Nucleotide excision repair and the ATR-mediated DNA damage checkpoint are two critical cellular responses to the genotoxic stress induced by ultraviolet (UV) light and are important for cancer prevention. In vivo genetic data indicate that these global responses are coupled. Aziz Sancar et al. developed an in vitro coupled repair-checkpoint system to analyze the basic steps of these DNA damage stress responses in a biochemically defined system. The minimum set of factors essential for repair-checkpoint coupling include damaged DNA, the excision repair factors (XPA, XPC, XPF-ERCC1, XPG, TFIIH, RPA), the 5'-3' exonuclease EXO1, and the damage checkpoint proteins ATR-ATRIP and TopBP1. This coupled repair-checkpoint system was used to demonstrate that the ~30 nucleotide single-stranded DNA (ssDNA) gap generated by nucleotide excision repair is enlarged by EXO1 and bound by RPA to generate the signal that activates ATR.
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Affiliation(s)
- Laura A Lindsey-Boltz
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC
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15
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Abstract
Each time a cell duplicates, the whole genome must be accurately copied and distributed. The enormous amount of DNA in eukaryotic cells requires a high level of coordination between polymerases and other DNA and chromatin-interacting proteins to ensure timely and accurate DNA replication and chromatin formation. PCNA forms a ring that encircles the DNA. It serves as a processivity factor for DNA polymerases and as a landing platform for different proteins that interact with DNA and chromatin. It thus serves as a signaling hub and influences the rate and accuracy of DNA replication, the r-formation of chromatin in the wake of the moving fork and the proper segregation of the sister chromatids. Four different, conserved, protein complexes are in charge of loading/unloading PCNA and similar molecules onto DNA. Replication factor C (RFC) is the canonical complex in charge of loading PCNA, the replication clamp, during S-phase. The Rad24, Ctf18 and Elg1 proteins form complexes similar to RFC, with particular functions in the cell's nucleus. Here we summarize our current knowledge about the roles of these important factors in yeast.
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Affiliation(s)
- Martin Kupiec
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69978, Israel
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16
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Fukumoto Y, Ikeuchi M, Nakayama Y, Yamaguchi N. The KYxxL motif in Rad17 protein is essential for the interaction with the 9-1-1 complex. Biochem Biophys Res Commun 2016; 477:982-987. [PMID: 27387238 DOI: 10.1016/j.bbrc.2016.07.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 07/02/2016] [Indexed: 11/28/2022]
Abstract
ATR-dependent DNA damage checkpoint is the major DNA damage checkpoint against UV irradiation and DNA replication stress. The Rad17-RFC and Rad9-Rad1-Hus1 (9-1-1) complexes interact with each other to contribute to ATR signaling, however, the precise regulatory mechanism of the interaction has not been established. Here, we identified a conserved sequence motif, KYxxL, in the AAA+ domain of Rad17 protein, and demonstrated that this motif is essential for the interaction with the 9-1-1 complex. We also show that UV-induced Rad17 phosphorylation is increased in the Rad17 KYxxL mutants. These data indicate that the interaction with the 9-1-1 complex is not required for Rad17 protein to be an efficient substrate for the UV-induced phosphorylation. Our data also raise the possibility that the 9-1-1 complex plays a negative regulatory role in the Rad17 phosphorylation. We also show that the nucleotide-binding activity of Rad17 is required for its nuclear localization.
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Affiliation(s)
- Yasunori Fukumoto
- Laboratory of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan.
| | - Masayoshi Ikeuchi
- Department of Biochemistry & Molecular Biology, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Yuji Nakayama
- Department of Biochemistry & Molecular Biology, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Naoto Yamaguchi
- Laboratory of Molecular Cell Biology, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan.
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17
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Sancar A. Mechanisms of DNA Repair by Photolyase and Excision Nuclease (Nobel Lecture). Angew Chem Int Ed Engl 2016; 55:8502-27. [PMID: 27337655 DOI: 10.1002/anie.201601524] [Citation(s) in RCA: 174] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Indexed: 01/27/2023]
Abstract
Ultraviolet light damages DNA by converting two adjacent thymines into a thymine dimer which is potentially mutagenic, carcinogenic, or lethal to the organism. This damage is repaired by photolyase and the nucleotide excision repair system in E. coli by nucleotide excision repair in humans. The work leading to these results is presented by Aziz Sancar in his Nobel Lecture.
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Affiliation(s)
- Aziz Sancar
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA.
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Sancar A. Mechanismen der DNA-Reparatur durch Photolyasen und Exzisionsnukleasen (Nobel-Aufsatz). Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201601524] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Aziz Sancar
- Department of Biochemistry and Biophysics; University of North Carolina School of Medicine; Chapel Hill North Carolina USA
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Teixeira V, Costa V. Unraveling the role of the Target of Rapamycin signaling in sphingolipid metabolism. Prog Lipid Res 2015; 61:109-33. [PMID: 26703187 DOI: 10.1016/j.plipres.2015.11.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 11/04/2015] [Accepted: 11/09/2015] [Indexed: 02/06/2023]
Abstract
Sphingolipids are important bioactive molecules that regulate basic aspects of cellular metabolism and physiology, including cell growth, adhesion, migration, senescence, apoptosis, endocytosis, and autophagy in yeast and higher eukaryotes. Since they have the ability to modulate the activation of several proteins and signaling pathways, variations in the relative levels of different sphingolipid species result in important changes in overall cellular functions and fate. Sphingolipid metabolism and their route of synthesis are highly conserved from yeast to mammalian cells. Studies using the budding yeast Saccharomyces cerevisiae have served in many ways to foster our understanding of sphingolipid dynamics and their role in the regulation of cellular processes. In the past decade, studies in S. cerevisiae have unraveled a functional association between the Target of Rapamycin (TOR) pathway and sphingolipids, showing that both TOR Complex 1 (TORC1) and TOR Complex 2 (TORC2) branches control temporal and spatial aspects of sphingolipid metabolism in response to physiological and environmental cues. In this review, we report recent findings in this emerging and exciting link between the TOR pathway and sphingolipids and implications in human health and disease.
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Affiliation(s)
- Vitor Teixeira
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Porto, Portugal; ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Departamento de Biologia Molecular, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Vítor Costa
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Porto, Portugal; ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Departamento de Biologia Molecular, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
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20
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Kaufman KL, Jenkins Y, Alomari M, Mirzaei M, Best OG, Pascovici D, Mactier S, Mulligan SP, Haynes PA, Christopherson RI. The Hsp90 inhibitor SNX-7081 is synergistic with fludarabine nucleoside via DNA damage and repair mechanisms in human, p53-negative chronic lymphocytic leukemia. Oncotarget 2015; 6:40981-97. [PMID: 26556860 PMCID: PMC4747384 DOI: 10.18632/oncotarget.5715] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 09/16/2015] [Indexed: 12/31/2022] Open
Abstract
Clinical trials of heat shock protein 90 (Hsp90) inhibitors have been limited by high toxicity. We previously showed that the Hsp90 inhibitor, SNX-7081, synergizes with and restores sensitivity to fludarabine nucleoside (2-FaraA) in human chronic lymphocytic leukemia (CLL) cells with lesions in the p53 pathway (Best OG, et al., Leukemia Lymphoma 53:1367-75, 2012). Here, we used label-free quantitative shotgun proteomics and comprehensive bioinformatic analysis to determine the mechanism of this synergy. We propose that 2-FaraA-induced DNA damage is compounded by SNX-7081-mediated inhibition of DNA repair, resulting in enhanced induction of apoptosis. DNA damage responses are impaired in part due to reductions in checkpoint regulators BRCA1 and cyclin D1, and cell death is triggered following reductions of MYC and nucleolin and an accumulation of apoptosis-inducing NFkB2 p100 subunit. Loss of nucleolin can activate Fas-mediated apoptosis, leading to the increase of pro-apoptotic proteins (BID, fas-associated factor-2) and subsequent apoptosis of p53-negative, 2-FaraA refractory CLL cells. A significant induction of DNA damage, indicated by increases in DNA damage marker γH2AX, was observed following the dual drug treatment of additional cell lines, indicating that a similar mechanism may operate in other p53-mutated human B-lymphoid cancers. These results provide valuable insight into the synergistic mechanism between SNX-7081 and 2-FaraA that may provide an alternative treatment for CLL patients with p53 mutations, for whom therapeutic options are currently limited. Moreover, this drug combination reduces the effective dose of the Hsp90 inhibitor and may therefore alleviate any toxicity encountered.
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MESH Headings
- Antineoplastic Agents/pharmacology
- Apoptosis/drug effects
- BRCA1 Protein/metabolism
- Benzamides/pharmacology
- Blotting, Western
- Cell Line, Tumor
- Chromatography, Liquid/methods
- Cyclin D1/metabolism
- DNA Damage
- DNA Repair/drug effects
- Drug Synergism
- HSP90 Heat-Shock Proteins/antagonists & inhibitors
- HSP90 Heat-Shock Proteins/metabolism
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/genetics
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- Mutation
- NF-kappa B p52 Subunit/metabolism
- Phosphoproteins/metabolism
- Protein Interaction Maps/drug effects
- Proteomics/methods
- Proto-Oncogene Proteins c-myc/metabolism
- RNA-Binding Proteins/metabolism
- Signal Transduction/drug effects
- Signal Transduction/genetics
- Tandem Mass Spectrometry
- Tumor Suppressor Protein p53/genetics
- Tumor Suppressor Protein p53/metabolism
- Vidarabine/analogs & derivatives
- Vidarabine/pharmacology
- Nucleolin
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Affiliation(s)
- Kimberley L. Kaufman
- School of Molecular Bioscience, University of Sydney, Darlington, NSW 2006, Australia
- Molecular Neuropathology, Brain and Mind Centre, Camperdown, NSW 2050, Australia
| | - Yiping Jenkins
- School of Molecular Bioscience, University of Sydney, Darlington, NSW 2006, Australia
| | - Munther Alomari
- School of Molecular Bioscience, University of Sydney, Darlington, NSW 2006, Australia
| | - Mehdi Mirzaei
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - O. Giles Best
- Northern Blood Research Centre, Kolling Institute for Medical Research, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Dana Pascovici
- Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW 2109, Australia
| | - Swetlana Mactier
- School of Molecular Bioscience, University of Sydney, Darlington, NSW 2006, Australia
| | - Stephen P. Mulligan
- Northern Blood Research Centre, Kolling Institute for Medical Research, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Paul A. Haynes
- Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia
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Lindsey-Boltz LA, Kemp MG, Capp C, Sancar A. RHINO forms a stoichiometric complex with the 9-1-1 checkpoint clamp and mediates ATR-Chk1 signaling. Cell Cycle 2015; 14:99-108. [PMID: 25602520 DOI: 10.4161/15384101.2014.967076] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The ATR-Chk1 signaling pathway mediates cellular responses to DNA damage and replication stress and is composed of a number of core factors that are conserved throughout eukaryotic organisms. However, humans and other higher eukaryotic species possess additional factors that are implicated in the regulation of this signaling network but that have not been extensively studied. Here we show that RHINO (for Rad9, Rad1, Hus1 interacting nuclear orphan) forms complexes with both the 9-1-1 checkpoint clamp and TopBP1 in human cells even in the absence of treatments with DNA damaging agents via direct interactions with the Rad9 and Rad1 subunits of the 9-1-1 checkpoint clamp and with the ATR kinase activator TopBP1. The interaction of RHINO with 9-1-1 was of sufficient affinity to allow for the purification of a stable heterotetrameric RHINO-Rad9-Hus1-Rad1 complex in vitro. In human cells, a portion of RHINO localizes to chromatin in the absence of DNA damage, and this association is enriched following UV irradiation. Furthermore, we find that the tethering of a Lac Repressor (LacR)-RHINO fusion protein to LacO repeats in chromatin of mammalian cells induces Chk1 phosphorylation in a Rad9- and Claspin-dependent manner. Lastly, the loss of RHINO partially abrogates ATR-Chk1 signaling following UV irradiation without impacting the interaction of the 9-1-1 clamp with TopBP1 or the loading of 9-1-1 onto chromatin. We conclude that RHINO is a bona fide regulator of ATR-Chk1 signaling in mammalian cells.
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Key Words
- 9-1-1, Rad9-Hus1-Rad1
- ATR, Ataxia telangiectasia-mutated and Rad3-related
- DNA damage checkpoint
- DNA damage response
- IP, immunoprecipitation
- RHINO, Rad9, Hus1, Rad1 interacting nuclear orphan
- RPA, Replication Protein A
- TopBP1, Topoisomerase binding protein 1
- UV, ultraviolet
- checkpoint clamp
- checkpoint kinase
- chromatin
- protein-protein interaction
- ssDNA, single-stranded DNA
- ultraviolet light
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Affiliation(s)
- Laura A Lindsey-Boltz
- a From the Department of Biochemistry and Biophysics ; University of North Carolina School of Medicine ; Chapel Hill , NC USA
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Distinct functional consequences of MUTYH variants associated with colorectal cancer: Damaged DNA affinity, glycosylase activity and interaction with PCNA and Hus1. DNA Repair (Amst) 2015; 34:39-51. [PMID: 26377631 DOI: 10.1016/j.dnarep.2015.08.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 08/03/2015] [Indexed: 12/13/2022]
Abstract
MUTYH is a base excision repair (BER) enzyme that prevents mutations in DNA associated with 8-oxoguanine (OG) by catalyzing the removal of adenine from inappropriately formed OG:A base-pairs. Germline mutations in the MUTYH gene are linked to colorectal polyposis and a high risk of colorectal cancer, a syndrome referred to as MUTYH-associated polyposis (MAP). There are over 300 different MUTYH mutations associated with MAP and a large fraction of these gene changes code for missense MUTYH variants. Herein, the adenine glycosylase activity, mismatch recognition properties, and interaction with relevant protein partners of human MUTYH and five MAP variants (R295C, P281L, Q324H, P502L, and R520Q) were examined. P281L MUTYH was found to be severely compromised both in DNA binding and base excision activity, consistent with the location of this variation in the iron-sulfur cluster (FCL) DNA binding motif of MUTYH. Both R295C and R520Q MUTYH were found to have low fractions of active enzyme, compromised affinity for damaged DNA, and reduced rates for adenine excision. In contrast, both Q324H and P502L MUTYH function relatively similarly to WT MUTYH in both binding and glycosylase assays. However, P502L and R520Q exhibited reduced affinity for PCNA (proliferation cell nuclear antigen), consistent with their location in the PCNA-binding motif of MUTYH. Whereas, only Q324H, and not R295C, was found to have reduced affinity for Hus1 of the Rad9-Hus1-Rad1 complex, despite both being localized to the same region implicated for interaction with Hus1. These results underscore the diversity of functional consequences due to MUTYH variants that may impact the progression of MAP.
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23
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Takeishi Y, Iwaya-Omi R, Ohashi E, Tsurimoto T. Intramolecular Binding of the Rad9 C Terminus in the Checkpoint Clamp Rad9-Hus1-Rad1 Is Closely Linked with Its DNA Binding. J Biol Chem 2015; 290:19923-32. [PMID: 26088138 DOI: 10.1074/jbc.m115.669002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Indexed: 12/20/2022] Open
Abstract
The human checkpoint clamp Rad9-Hus1-Rad1 (9-1-1) is loaded onto chromatin by its loader complex, Rad17-RFC, following DNA damage. The 120-amino acid (aa) stretch of the Rad9 C terminus (C-tail) is unstructured and projects from the core ring structure (CRS). Recent studies showed that 9-1-1 and CRS bind DNA independently of Rad17-RFC. The DNA-binding affinity of mutant 9(ΔC)-1-1, which lacked the Rad9 C-tail, was much higher than that of wild-type 9-1-1, suggesting that 9-1-1 has intrinsic DNA binding activity that manifests in the absence of the C-tail. C-tail added in trans interacted with CRS and prevented it from binding to DNA. We narrowed down the amino acid sequence in the C-tail necessary for CRS binding to a 15-aa stretch harboring two conserved consecutive phenylalanine residues. We prepared 9-1-1 mutants containing the variant C-tail deficient for CRS binding, and we demonstrated that the mutant form restored DNA binding as efficiently as 9(ΔC)-1-1. Furthermore, we mapped the sequence necessary for TopBP1 binding within the same 15-aa stretch, demonstrating that TopBP1 and CRS share the same binding region in the C-tail. Indeed, we observed their competitive binding to the C-tail with purified proteins. The importance of interaction between 9-1-1 and TopBP1 for DNA damage signaling suggests that the competitive interactions of TopBP1 and CRS with the C-tail will be crucial for the activation mechanism.
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Affiliation(s)
- Yukimasa Takeishi
- From the Department of Biology, Faculty of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | - Rie Iwaya-Omi
- From the Department of Biology, Faculty of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | - Eiji Ohashi
- From the Department of Biology, Faculty of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
| | - Toshiki Tsurimoto
- From the Department of Biology, Faculty of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
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24
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Falgreen S, Dybkær K, Young KH, Xu-Monette ZY, El-Galaly TC, Laursen MB, Bødker JS, Kjeldsen MK, Schmitz A, Nyegaard M, Johnsen HE, Bøgsted M. Predicting response to multidrug regimens in cancer patients using cell line experiments and regularised regression models. BMC Cancer 2015; 15:235. [PMID: 25881228 PMCID: PMC4396063 DOI: 10.1186/s12885-015-1237-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 03/20/2015] [Indexed: 11/30/2022] Open
Abstract
Background Patients suffering from cancer are often treated with a range of chemotherapeutic agents, but the treatment efficacy varies greatly between patients. Based on recent popularisation of regularised regression models the goal of this study was to establish workflows for pharmacogenomic predictors of response to standard multidrug regimens using baseline gene expression data and origin specific cell lines. The proposed workflows are tested on diffuse large B-cell lymphoma treated with R-CHOP first-line therapy. Methods First, B-cell cancer cell lines were tested successively for resistance towards the chemotherapeutic components of R-CHOP: cyclophosphamide (C), doxorubicin (H), and vincristine (O). Second, baseline gene expression data were obtained for each cell line before treatment. Third, regularised multivariate regression models with cross-validated tuning parameters were used to generate classifier and predictor based resistance gene signatures (REGS) for the combination and individual chemotherapeutic drugs C, H, and O. Fourth, each developed REGS was used to assign resistance levels to individual patients in three clinical cohorts. Results Both classifier and predictor based REGS, for the combination CHO, were of prognostic value. For patients classified as resistant towards CHO the risk of progression was 2.33 (95% CI: 1.6, 3.3) times greater than for those classified as sensitive. Similarly, an increase in the predicted CHO resistance index of 10 was related to a 22% (9%, 36%) increased risk of progression. Furthermore, the REGS classifier performed significantly better than the REGS predictor. Conclusions The regularised multivariate regression models provide a flexible workflow for drug resistance studies with promising potential. However, the gene expressions defining the REGSs should be functionally validated and correlated to known biomarkers to improve understanding of molecular mechanisms of drug resistance. Electronic supplementary material The online version of this article (doi:10.1186/s12885-015-1237-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Steffen Falgreen
- Department of Haematology, Research Section, Aalborg University Hospital, Sdr. Skovvej 15, 9000, Aalborg, Denmark.
| | - Karen Dybkær
- Department of Haematology, Research Section, Aalborg University Hospital, Sdr. Skovvej 15, 9000, Aalborg, Denmark. .,Department of Clinical Medicine, Aalborg University, Aalborg, Denmark. .,Clinical Cancer Research Center, Aalborg University Hospital, Aalborg, Denmark.
| | - Ken H Young
- Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
| | - Zijun Y Xu-Monette
- Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
| | - Tarec C El-Galaly
- Department of Haematology, Research Section, Aalborg University Hospital, Sdr. Skovvej 15, 9000, Aalborg, Denmark. .,Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.
| | - Maria Bach Laursen
- Department of Haematology, Research Section, Aalborg University Hospital, Sdr. Skovvej 15, 9000, Aalborg, Denmark.
| | - Julie S Bødker
- Department of Haematology, Research Section, Aalborg University Hospital, Sdr. Skovvej 15, 9000, Aalborg, Denmark.
| | - Malene K Kjeldsen
- Department of Haematology, Research Section, Aalborg University Hospital, Sdr. Skovvej 15, 9000, Aalborg, Denmark.
| | - Alexander Schmitz
- Department of Haematology, Research Section, Aalborg University Hospital, Sdr. Skovvej 15, 9000, Aalborg, Denmark.
| | - Mette Nyegaard
- Department of Haematology, Research Section, Aalborg University Hospital, Sdr. Skovvej 15, 9000, Aalborg, Denmark. .,Department of Biomedicine, Aarhus University, Aarhus, Denmark.
| | - Hans Erik Johnsen
- Department of Haematology, Research Section, Aalborg University Hospital, Sdr. Skovvej 15, 9000, Aalborg, Denmark. .,Department of Clinical Medicine, Aalborg University, Aalborg, Denmark. .,Clinical Cancer Research Center, Aalborg University Hospital, Aalborg, Denmark.
| | - Martin Bøgsted
- Department of Haematology, Research Section, Aalborg University Hospital, Sdr. Skovvej 15, 9000, Aalborg, Denmark. .,Department of Clinical Medicine, Aalborg University, Aalborg, Denmark. .,Clinical Cancer Research Center, Aalborg University Hospital, Aalborg, Denmark.
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25
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Module organization and variance in protein-protein interaction networks. Sci Rep 2015; 5:9386. [PMID: 25797237 PMCID: PMC4369690 DOI: 10.1038/srep09386] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 03/03/2015] [Indexed: 12/13/2022] Open
Abstract
A module is a group of closely related proteins that act in concert to perform specific biological functions through protein–protein interactions (PPIs) that occur in time and space. However, the underlying module organization and variance remain unclear. In this study, we collected module templates to infer respective module families, including 58,041 homologous modules in 1,678 species, and PPI families using searches of complete genomic database. We then derived PPI evolution scores and interface evolution scores to describe the module elements, including core and ring components. Functions of core components were highly correlated with those of essential genes. In comparison with ring components, core proteins/PPIs were conserved across multiple species. Subsequently, protein/module variance of PPI networks confirmed that core components form dynamic network hubs and play key roles in various biological functions. Based on the analyses of gene essentiality, module variance, and gene co-expression, we summarize the observations of module organization and variance as follows: 1) a module consists of core and ring components; 2) core components perform major biological functions and collaborate with ring components to execute certain functions in some cases; 3) core components are more conserved and essential during organizational changes in different biological states or conditions.
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26
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Czarny P, Pawlowska E, Bialkowska-Warzecha J, Kaarniranta K, Blasiak J. Autophagy in DNA damage response. Int J Mol Sci 2015; 16:2641-62. [PMID: 25625517 PMCID: PMC4346856 DOI: 10.3390/ijms16022641] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 01/12/2015] [Indexed: 12/15/2022] Open
Abstract
DNA damage response (DDR) involves DNA repair, cell cycle regulation and apoptosis, but autophagy is also suggested to play a role in DDR. Autophagy can be activated in response to DNA-damaging agents, but the exact mechanism underlying this activation is not fully understood, although it is suggested that it involves the inhibition of mammalian target of rapamycin complex 1 (mTORC1). mTORC1 represses autophagy via phosphorylation of the ULK1/2-Atg13-FIP200 complex thus preventing maturation of pre-autophagosomal structures. When DNA damage occurs, it is recognized by some proteins or their complexes, such as poly(ADP)ribose polymerase 1 (PARP-1), Mre11-Rad50-Nbs1 (MRN) complex or FOXO3, which activate repressors of mTORC1. SQSTM1/p62 is one of the proteins whose levels are regulated via autophagic degradation. Inhibition of autophagy by knockout of FIP200 results in upregulation of SQSTM1/p62, enhanced DNA damage and less efficient damage repair. Mitophagy, one form of autophagy involved in the selective degradation of mitochondria, may also play role in DDR. It degrades abnormal mitochondria and can either repress or activate apoptosis, but the exact mechanism remains unknown. There is a need to clarify the role of autophagy in DDR, as this process may possess several important biomedical applications, involving also cancer therapy.
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Affiliation(s)
- Piotr Czarny
- Department of Molecular Genetics, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland.
| | - Elzbieta Pawlowska
- Department of Orthodontics, Medical University of Lodz, Pomorska 251, 92-216 Lodz, Poland.
| | - Jolanta Bialkowska-Warzecha
- Department of Infectious and Liver Diseases, Medical University of Lodz, Kniaziewicza 1/5, 92-347 Lodz, Poland.
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio FI-70211, Finland.
| | - Janusz Blasiak
- Department of Molecular Genetics, University of Lodz, Pomorska 141/143, 90-236 Lodz, Poland.
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Elg1, a central player in genome stability. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2014; 763:267-79. [PMID: 25795125 DOI: 10.1016/j.mrrev.2014.11.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/15/2014] [Accepted: 11/17/2014] [Indexed: 11/20/2022]
Abstract
ELG1 is a conserved gene uncovered in a number of genetic screens in yeast aimed at identifying factors important in the maintenance of genome stability. Elg1's activity prevents gross chromosomal rearrangements, maintains proper telomere length regulation, helps repairing DNA damage created by a number of genotoxins and participates in sister chromatid cohesion. Elg1 is evolutionarily conserved, and its mammalian ortholog (also known as ATAD5) is embryonic lethal when lost in mice, acts as a tumor suppressor in mice and humans, exhibits physical interactions with components of the human Fanconi Anemia pathway and may be responsible for some of the phenotypes associated with neurofibromatosis. In this review, we summarize the information available on Elg1-related activities in yeast and mammals, and present models to explain how the different phenotypes observed in the absence of Elg1 activity are related.
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The MRE11 complex: An important source of stress relief. Exp Cell Res 2014; 329:162-9. [DOI: 10.1016/j.yexcr.2014.10.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 10/01/2014] [Accepted: 10/06/2014] [Indexed: 12/11/2022]
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The Mcm2-7 replicative helicase: a promising chemotherapeutic target. BIOMED RESEARCH INTERNATIONAL 2014; 2014:549719. [PMID: 25243149 PMCID: PMC4163376 DOI: 10.1155/2014/549719] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 08/08/2014] [Accepted: 08/10/2014] [Indexed: 02/05/2023]
Abstract
Numerous eukaryotic replication factors have served as chemotherapeutic targets. One replication factor that has largely escaped drug development is the Mcm2-7 replicative helicase. This heterohexameric complex forms the licensing system that assembles the replication machinery at origins during initiation, as well as the catalytic core of the CMG (Cdc45-Mcm2-7-GINS) helicase that unwinds DNA during elongation. Emerging evidence suggests that Mcm2-7 is also part of the replication checkpoint, a quality control system that monitors and responds to DNA damage. As the only replication factor required for both licensing and DNA unwinding, Mcm2-7 is a major cellular regulatory target with likely cancer relevance. Mutations in at least one of the six MCM genes are particularly prevalent in squamous cell carcinomas of the lung, head and neck, and prostrate, and MCM mutations have been shown to cause cancer in mouse models. Moreover various cellular regulatory proteins, including the Rb tumor suppressor family members, bind Mcm2-7 and inhibit its activity. As a preliminary step toward drug development, several small molecule inhibitors that target Mcm2-7 have been recently discovered. Both its structural complexity and essential role at the interface between DNA replication and its regulation make Mcm2-7 a potential chemotherapeutic target.
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Agustina L, Hahm SH, Han SH, Tran AHV, Chung JH, Park JH, Park JW, Han YS. Visualization of the physical and functional interaction between hMYH and hRad9 by Dronpa bimolecular fluorescence complementation. BMC Mol Biol 2014; 15:17. [PMID: 25127721 PMCID: PMC4151078 DOI: 10.1186/1471-2199-15-17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 08/04/2014] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Human MutY glycosylase homolog (hMYH), a component of the base excision repair pathway, is responsible for the generation of apurinic/apyrimidinic sites. Rad9-Rad1-Hus1 (9-1-1) is a heterotrimeric protein complex that plays a role in cell cycle checkpoint control and DNA repair. In humans, hMYH and 9-1-1 interact through Hus1 and to a lesser degree with Rad1 in the presence of DNA damage. In Saccharomyces pombe, each component of the 9-1-1 complex interacts directly with SpMYH. The glycosylase activity of hMYH is stimulated by Hus1 and the 9-1-1 complex and enhanced by DNA damage treatment. Cells respond to different stress conditions in different manners. Therefore, we investigated whether Rad9 interacted with hMYH under different stresses. Here, we identified and visualized the interaction between hRad9 and hMYH and investigated the functional consequences of this interaction. RESULTS Co-IP and BiFC indicates that hMYH interacts with hRad9. As shown by GST-pull down assay, this interaction is direct. Furthermore, BiFC with deletion mutants of hMYH showed that hRad9 interacts with N-terminal region of hMYH. The interaction was enhanced by hydroxyurea (HU) treatment. mRNA and protein levels of hMYH and hRad9 were increased following HU treatment. A marked increase in p-Chk1 (S345) and p-Cdk2 (T14, Y15) was observed. But this phosphorylation decreased in siMYH- or siRad9-transfected cells, and more pronounced decrease observed in co-transfected cells. CONCLUSIONS Our data reveal that hRad9 interacts directly with N-terminal region of hMYH. This interaction is enhanced by HU treatment. Knockdown of one or both protein result in decreasing Chk1 and Cdk2 phosphorylation. Since both protein functions in the early detection of DNA damage, we suggest that this interaction occurs early in DNA damage pathway.
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Affiliation(s)
- Lia Agustina
- Department of Advanced Technology Fusion, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea
| | - Soo-Hyun Hahm
- Department of Advanced Technology Fusion, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea
| | - Se Hee Han
- Department of Advanced Technology Fusion, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea
| | - An Hue Vy Tran
- Department of Advanced Technology Fusion, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea
| | - Ji Hyung Chung
- Department of Applied Bioscience, College of Life Science, CHA University, Gyeonggi-do 463-836, Korea
| | - Jong-Hwa Park
- Department of Genetic Engineering and Graduate School of Biotechnology, Kyung Hee University, Yongin 446-701, Korea
| | - Jin Woo Park
- BioActs, DKC Corporation, 693-2 Gojan-dong, Namdong-gu, Incheon 405-820, Korea
| | - Ye Sun Han
- Department of Advanced Technology Fusion, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea
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Ngo GHP, Balakrishnan L, Dubarry M, Campbell JL, Lydall D. The 9-1-1 checkpoint clamp stimulates DNA resection by Dna2-Sgs1 and Exo1. Nucleic Acids Res 2014; 42:10516-28. [PMID: 25122752 PMCID: PMC4176354 DOI: 10.1093/nar/gku746] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Single-stranded DNA (ssDNA) at DNA ends is an important regulator of the DNA damage response. Resection, the generation of ssDNA, affects DNA damage checkpoint activation, DNA repair pathway choice, ssDNA-associated mutation and replication fork stability. In eukaryotes, extensive DNA resection requires the nuclease Exo1 and nuclease/helicase pair: Dna2 and Sgs1BLM. How Exo1 and Dna2-Sgs1BLM coordinate during resection remains poorly understood. The DNA damage checkpoint clamp (the 9-1-1 complex) has been reported to play an important role in stimulating resection but the exact mechanism remains unclear. Here we show that the human 9-1-1 complex enhances the cleavage of DNA by both DNA2 and EXO1 in vitro, showing that the resection-stimulatory role of the 9-1-1 complex is direct. We also show that in Saccharomyces cerevisiae, the 9-1-1 complex promotes both Dna2-Sgs1 and Exo1-dependent resection in response to uncapped telomeres. Our results suggest that the 9-1-1 complex facilitates resection by recruiting both Dna2-Sgs1 and Exo1 to sites of resection. This activity of the 9-1-1 complex in supporting resection is strongly inhibited by the checkpoint adaptor Rad953BP1. Our results provide important mechanistic insights into how DNA resection is regulated by checkpoint proteins and have implications for genome stability in eukaryotes.
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Affiliation(s)
- Greg H P Ngo
- Institute for Cell and Molecular Biosciences (ICaMB), Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Lata Balakrishnan
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Marion Dubarry
- Institute for Cell and Molecular Biosciences (ICaMB), Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Judith L Campbell
- Divisions of Biology and Chemistry, Caltech, Braun Laboratories, Pasadena, CA 91125, USA
| | - David Lydall
- Institute for Cell and Molecular Biosciences (ICaMB), Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
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32
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Fukumoto Y, Miura T, Morii M, Kubota S, Honda T, Kubota S, Morinaga T, Yamaguchi N, Nakayama Y, Yamaguchi N. v-Src inhibits the interaction between Rad17 and Rad9 and induces replication fork collapse. Biochem Biophys Res Commun 2014; 450:885-90. [DOI: 10.1016/j.bbrc.2014.06.078] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 06/17/2014] [Indexed: 12/27/2022]
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Pierzchala M, Hoekman AJW, Urbanski P, Kruijt L, Kristensen L, Young JF, Oksbjerg N, Goluch D, te Pas MFW. Validation of biomarkers for loin meat quality (M. longissimus) of pigs. J Anim Breed Genet 2014; 131:258-70. [PMID: 24506540 DOI: 10.1111/jbg.12081] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 01/04/2014] [Indexed: 11/29/2022]
Abstract
The aim of this study was to validate previously reported associations between microarray gene expression levels and pork quality traits using real-time PCR. Meat samples and meat quality data from 100 pigs were collected from a different pig breed to the one tested by microarray (Large White versus Pietrain) and a different country of origin (Denmark versus Germany). Ten genes (CARP, MB, CSRP3, TNNC1, VAPB, TNNI1, HSPB1, TNNT1, TIMP-1, RAD-like) were chosen from the original microarray study on the basis of the association between gene expression levels and the meat quality traits meat %, back fat, pH24, drip loss %, colour a*, colour b*, colour L*, WB-SF, SFA, MUFA, PUFA. Real-time PCR detection methods were developed for validation of all ten genes, confirming association with drip loss (two of two genes), ultimate pH (three of four genes), a* (redness) (two of six genes) and L*(lightness) (two of four genes). Furthermore, several new correlations for MUFA and PUFA were established due to additional meat quality trait information on fatty acid composition not available for the microarray study. Regression studies showed that the maximum explanation of the phenotypic variance of the meat quality traits was 50% for the ultimate pH trait using these ten genes only. Additional studies showed that the gene expression of several of the genes was correlated with each other. We conclude that the genes initially selected from the microarray study were robust, explaining variances of the genes for the meat quality traits.
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Affiliation(s)
- M Pierzchala
- Animal Breeding and Genetics Centre, Wageningen UR Livestock Research, Lelystad, The Netherlands; Institute of Genetics and Animal Breeding, Polish Academy of Science, Jastrzebiec, Poland
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Ronald S, Awate S, Rath A, Carroll J, Galiano F, Dwyer D, Kleiner-Hancock H, Mathis JM, Vigod S, De Benedetti A. Phenothiazine Inhibitors of TLKs Affect Double-Strand Break Repair and DNA Damage Response Recovery and Potentiate Tumor Killing with Radiomimetic Therapy. Genes Cancer 2013; 4:39-53. [PMID: 23946870 DOI: 10.1177/1947601913479020] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Accepted: 01/25/2013] [Indexed: 11/16/2022] Open
Abstract
The Tousled-like kinases (TLKs) are involved in chromatin assembly, DNA repair, and transcription. Two TLK genes exist in humans, and their expression is often dysregulated in cancer. TLKs phosphorylate Asf1 and Rad9, regulating double-strand break (DSB) repair and the DNA damage response (DDR). TLKs maintain genomic stability and are important therapeutic intervention targets. We identified specific inhibitors of TLKs from several compound libraries, some of which belong to the family of phenothiazine antipsychotics. The inhibitors prevented the TLK-mediated phosphorylation of Rad9(S328) and impaired checkpoint recovery and DSB repair. The inhibitor thioridazine (THD) potentiated tumor killing with chemotherapy and also had activity alone. Staining for γ-H2AX revealed few positive cells in untreated tumors, but large numbers in mice treated with low doxorubicin or THD alone, possibly the result of the accumulation of DSBs that are not promptly repaired as they may occur in the harsh tumor growth environment.
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Affiliation(s)
- Sharon Ronald
- Department of Biochemistry and Molecular Biology and the Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center Shreveport, Shreveport, LA, USA
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35
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Kubota T, Myung K, Donaldson AD. Is PCNA unloading the central function of the Elg1/ATAD5 replication factor C-like complex? Cell Cycle 2013; 12:2570-9. [PMID: 23907118 PMCID: PMC3865047 DOI: 10.4161/cc.25626] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Maintaining genome stability is crucial for all cells. The budding yeast Elg1 protein, the major subunit of a replication factor C-like complex, is important for genome stability, since cells lacking Elg1 exhibit increased recombination and chromosomal rearrangements. This genome maintenance function of Elg1 seems to be conserved in higher eukaryotes, since removal of the human Elg1 homolog, encoded by the ATAD5 gene, also causes genome instability leading to tumorigenesis. The fundamental molecular function of the Elg1/ATAD5-replication factor C-like complex (RLC) was, until recently, elusive, although Elg1/ATAD5-RLC was known to interact with the replication sliding clamp PCNA. Two papers have now reported that following DNA replication, the Elg1/ATAD5-RLC is required to remove PCNA from chromatin in yeast and human cells. In this Review, we summarize the evidence that Elg1/ATAD5-RLC acts as a PCNA unloader and discuss the still enigmatic relationship between the function of Elg1/ATAD5-RLC in PCNA unloading and the role of Elg1/ATAD5 in maintaining genomic stability.
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Affiliation(s)
- Takashi Kubota
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, UK
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36
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Role of the checkpoint clamp in DNA damage response. Biomolecules 2013; 3:75-84. [PMID: 24970157 PMCID: PMC4030880 DOI: 10.3390/biom3010075] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/09/2013] [Accepted: 01/10/2013] [Indexed: 11/16/2022] Open
Abstract
DNA damage occurs during DNA replication, spontaneous chemical reactions, and assaults by external or metabolism-derived agents. Therefore, all living cells must constantly contend with DNA damage. Cells protect themselves from these genotoxic stresses by activating the DNA damage checkpoint and DNA repair pathways. Coordination of these pathways requires tight regulation in order to prevent genomic instability. The checkpoint clamp complex consists of Rad9, Rad1 and Hus1 proteins, and is often called the 9-1-1 complex. This PCNA (proliferating cell nuclear antigen)-like donut-shaped protein complex is a checkpoint sensor protein that is recruited to DNA damage sites during the early stage of the response, and is required for checkpoint activation. As PCNA is required for multiple pathways of DNA metabolism, the checkpoint clamp has also been implicated in direct roles in DNA repair, as well as in coordination of the pathways. Here we discuss roles of the checkpoint clamp in DNA damage response (DDR).
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37
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Lee KY, Fu H, Aladjem MI, Myung K. ATAD5 regulates the lifespan of DNA replication factories by modulating PCNA level on the chromatin. ACTA ACUST UNITED AC 2012; 200:31-44. [PMID: 23277426 PMCID: PMC3542800 DOI: 10.1083/jcb.201206084] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Reduction of ATAD5 extends the lifespan of replication factories by retaining PCNA and other replisome proteins on chromatin, leading to an increase in inactive replication factories and reduced overall replication rate. Temporal and spatial regulation of the replication factory is important for efficient DNA replication. However, the underlying molecular mechanisms are not well understood. Here, we report that ATAD5 regulates the lifespan of replication factories. Reduced expression of ATAD5 extended the lifespan of replication factories by retaining proliferating cell nuclear antigen (PCNA) and other replisome proteins on the chromatin during and even after DNA synthesis. This led to an increase of inactive replication factories with an accumulation of replisome proteins. Consequently, the overall replication rate was decreased, which resulted in the delay of S-phase progression. Prevalent detection of PCNA foci in G2 phase cells after ATAD5 depletion suggests that defects in the disassembly of replication factories persist after S phase is complete. ATAD5-mediated regulation of the replication factory and PCNA required an intact ATAD5 ATPase domain. Taken together, our data imply that ATAD5 regulates the cycle of DNA replication factories, probably through its PCNA-unloading activity.
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Affiliation(s)
- Kyoo-young Lee
- Genome Instability Section, Genetics and Molecular Biology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
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38
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Smith LA, Makarova AV, Samson L, Thiesen KE, Dhar A, Bessho T. Bypass of a psoralen DNA interstrand cross-link by DNA polymerases β, ι, and κ in vitro. Biochemistry 2012; 51:8931-8. [PMID: 23106263 DOI: 10.1021/bi3008565] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Repair of DNA interstrand cross-links in mammalian cells involves several biochemically distinctive processes, including the release of one of the cross-linked strands and translesion DNA synthesis (TLS). In this report, we investigated the in vitro TLS activity of a psoralen DNA interstrand cross-link by three DNA repair polymerases, DNA polymerases β, κ, and ι. DNA polymerase β is capable of bypassing a psoralen cross-link with a low efficiency. Cell extracts prepared from DNA polymerase β knockout mouse embryonic fibroblasts showed a reduced bypass activity of the psoralen cross-link, and purified DNA polymerase β restored the bypass activity. In addition, DNA polymerase ι misincorporated thymine across the psoralen cross-link and DNA polymerase κ extended these mispaired primer ends, suggesting that DNA polymerase ι may serve as an inserter and DNA polymerase κ may play a role as an extender in the repair of psoralen DNA interstrand cross-links. The results demonstrated here indicate that multiple DNA polymerases could participate in TLS steps in mammalian DNA interstrand cross-link repair.
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Affiliation(s)
- Leigh A Smith
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
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39
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De Benedetti A. The Tousled-Like Kinases as Guardians of Genome Integrity. ISRN MOLECULAR BIOLOGY 2012; 2012:627596. [PMID: 23869254 PMCID: PMC3712517 DOI: 10.5402/2012/627596] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The Tousled-like kinases (TLKs) function in processes of chromatin assembly, including replication, transcription, repair, and chromosome segregation. TLKs interact specifically (and phosphorylate) with the chromatin assembly factor Asf1, a histone H3-H4 chaperone, histone H3 itself at Ser10, and also Rad9, a key protein involved in DNA repair and cell cycle signaling following DNA damage. These interactions are believed to be responsible for the action of TLKs in double-stranded break repair and radioprotection and also in the propagation of the DNA damage response. Hence, I propose that TLKs play key roles in maintenance of genome integrity in many organisms of both kingdoms. In this paper, I highlight key issues of the known roles of these proteins, particularly in the context of DNA repair (IR and UV), their possible relevance to genome integrity and cancer development, and as possible targets for intervention in cancer management.
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Affiliation(s)
- Arrigo De Benedetti
- Department of Biochemistry and Molecular Biology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130, USA
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40
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Abstract
The eukaryotic RFC clamp loader couples the energy of ATP hydrolysis to open and close the circular PCNA sliding clamp onto primed sites for use by DNA polymerases and repair factors. Structural studies reveal clamp loaders to be heteropentamers. Each subunit contains a region of homology to AAA+ proteins that defines two domains. The AAA+ domains form a right-handed spiral upon binding ATP. This spiral arrangement generates a DNA binding site within the center of RFC. DNA enters the central chamber through a gap between the AAA+ domains of two subunits. Specificity for a primed template junction is achieved by a third domain that blocks DNA, forcing it to bend sharply. Thus only DNA with a flexible joint can bind the central chamber. DNA entry also requires a slot in the PCNA clamp, which is opened upon binding the AAA+ domains of the clamp loader. ATP hydrolysis enables clamp closing and ejection of RFC, completing the clamp loading reaction.
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Affiliation(s)
- Nina Y Yao
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA,
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41
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Yoshimura A, Akita M, Hosono Y, Abe T, Kobayashi M, Yamamoto KI, Tada S, Seki M, Enomoto T. Functional relationship between Claspin and Rad17. Biochem Biophys Res Commun 2011; 414:298-303. [PMID: 21945441 DOI: 10.1016/j.bbrc.2011.09.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 09/07/2011] [Indexed: 01/25/2023]
Abstract
Claspin was originally identified as a Check1 (Chk1)-interacting protein. Claspin and Rad17 are reportedly involved in the DNA damage-induced phosphorylation of Chk1, a hallmark of checkpoint activation. To understand the cellular functions of Claspin and the functional relationship between Claspin and Rad17, we generated Claspin(-/-) and Claspin(-/-)/RAD17(-) cells using chicken DT40 cells, which contain an exogenously introduced Claspin that can be suppressed by the addition of doxycycline (Dox). In the presence of Dox, Claspin(-/-) cells ceased growth within 2 days, leading to cell death. In addition, a remarkable reduction in the rate of DNA elongation was observed in Claspin-depleted cells, suggesting that Claspin plays a critical role in DNA replication in the absence of exogenous stress. When cells were exposed to methyl methanesulfonate (MMS), a DNA damaging agent, RAD17(-) cells showed a greater defect in checkpoint activation than Claspin(-/-) cells as monitored by progression of cell cycle and phosphorylation of Chk1. Knocking out RAD17 gene showed almost no additive effects on cell death and DNA elongation rates in Claspin-depleted cells.
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Affiliation(s)
- Akari Yoshimura
- Molecular Cell Biology Laboratory, Research Institute of Pharmaceutical Sciences, Faculty of Pharmacy, Musashino University, 1-1-20 Shinmachi, Nishitokyo-shi, Tokyo 202-8585, Japan
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Yilmaz S, Sancar A, Kemp MG. Multiple ATR-Chk1 pathway proteins preferentially associate with checkpoint-inducing DNA substrates. PLoS One 2011; 6:e22986. [PMID: 21829571 PMCID: PMC3146532 DOI: 10.1371/journal.pone.0022986] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 07/08/2011] [Indexed: 12/02/2022] Open
Abstract
The ATR-Chk1 DNA damage checkpoint pathway is a critical regulator of the cellular response to DNA damage and replication stress in human cells. The variety of environmental, chemotherapeutic, and carcinogenic agents that activate this signal transduction pathway do so primarily through the formation of bulky adducts in DNA and subsequent effects on DNA replication fork progression. Because there are many protein-protein and protein-DNA interactions proposed to be involved in activation and/or maintenance of ATR-Chk1 signaling in vivo, we systematically analyzed the association of a number of ATR-Chk1 pathway proteins with relevant checkpoint-inducing DNA structures in vitro. These DNA substrates included single-stranded DNA, branched DNA, and bulky adduct-containing DNA. We found that many checkpoint proteins show a preference for single-stranded, branched, and bulky adduct-containing DNA in comparison to undamaged, double-stranded DNA. We additionally found that the association of checkpoint proteins with bulky DNA damage relative to undamaged DNA was strongly influenced by the ionic strength of the binding reaction. Interestingly, among the checkpoint proteins analyzed the checkpoint mediator proteins Tipin and Claspin showed the greatest differential affinity for checkpoint-inducing DNA structures. We conclude that the association and accumulation of multiple checkpoint proteins with DNA structures indicative of DNA damage and replication stress likely contribute to optimal ATR-Chk1 DNA damage checkpoint responses.
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Affiliation(s)
- Seçil Yilmaz
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Aziz Sancar
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Michael G. Kemp
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
- * E-mail:
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Ishikawa K, Ishii H, Saito T, Ichimura K. Multiple functions of rad9 for preserving genomic integrity. Curr Genomics 2011; 7:477-80. [PMID: 18369403 DOI: 10.2174/138920206779315746] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2006] [Revised: 11/08/2006] [Accepted: 11/10/2006] [Indexed: 01/03/2023] Open
Abstract
DNA-damage checkpoints sense and respond to genomic damage. Human Rad9 (hRad9), an evolutionarily conserved gene with multiple functions for preserving genomic integrity, plays multiple roles in fundamental biological processes, including the regulation of the DNA damage response, cell cycle checkpoint control, DNA repair, apoptosis, transcriptional regulation, exonuclease activity, ribonucleotide synthesis and embryogenesis. This review examines work that provides significant insight into the molecular mechanisms of several individual cellular processes which might be beneficial for developing novel therapeutic approaches to cancerous diseases with genomic instability.
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Rodriguez-Rocha H, Aracely-Garcia-Garcia, Panayiotidis MI, Franco R. DNA damage and autophagy. Mutat Res 2011; 711:158-66. [PMID: 21419786 PMCID: PMC3105359 DOI: 10.1016/j.mrfmmm.2011.03.007] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 03/04/2011] [Accepted: 03/11/2011] [Indexed: 12/15/2022]
Abstract
Both exogenous and endogenous agents are a threat to DNA integrity. Exogenous environmental agents such as ultraviolet (UV) and ionizing radiation, genotoxic chemicals and endogenous byproducts of metabolism including reactive oxygen species can cause alterations in DNA structure (DNA damage). Unrepaired DNA damage has been linked to a variety of human disorders including cancer and neurodegenerative disease. Thus, efficient mechanisms to detect DNA lesions, signal their presence and promote their repair have been evolved in cells. If DNA is effectively repaired, DNA damage response is inactivated and normal cell functioning resumes. In contrast, when DNA lesions cannot be removed, chronic DNA damage triggers specific cell responses such as cell death and senescence. Recently, DNA damage has been shown to induce autophagy, a cellular catabolic process that maintains a balance between synthesis, degradation, and recycling of cellular components. But the exact mechanisms by which DNA damage triggers autophagy are unclear. More importantly, the role of autophagy in the DNA damage response and cellular fate is unknown. In this review we analyze evidence that supports a role for autophagy as an integral part of the DNA damage response.
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Affiliation(s)
- Humberto Rodriguez-Rocha
- Redox Biology Center and School of Veterinary Medicine and Biomedical Sciences. University of Nebraska-Lincoln. Lincoln, NE 68583
| | - Aracely-Garcia-Garcia
- Redox Biology Center and School of Veterinary Medicine and Biomedical Sciences. University of Nebraska-Lincoln. Lincoln, NE 68583
| | | | - Rodrigo Franco
- Redox Biology Center and School of Veterinary Medicine and Biomedical Sciences. University of Nebraska-Lincoln. Lincoln, NE 68583
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Targeted deletion of mouse Rad1 leads to deficient cellular DNA damage responses. Protein Cell 2011; 2:410-22. [PMID: 21637962 DOI: 10.1007/s13238-011-1049-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Accepted: 05/05/2011] [Indexed: 10/18/2022] Open
Abstract
The Rad1 gene is evolutionarily conserved from yeast to human. The fission yeast Schizosaccharomyces pombe Rad1 ortholog promotes cell survival against DNA damage and is required for G(2)/M checkpoint activation. In this study, mouse embryonic stem (ES) cells with a targeted deletion of Mrad1, the mouse ortholog of this gene, were created to evaluate its function in mammalian cells. Mrad1 (-/-) ES cells were highly sensitive to ultraviolet-light (UV light), hydroxyurea (HU) and gamma rays, and were defective in G(2)/M as well as S/M checkpoints. These data indicate that Mrad1 is required for repairing DNA lesions induced by UV-light, HU and gamma rays, and for mediating G(2)/M and S/M checkpoint controls. We further demonstrated that Mrad1 plays an important role in homologous recombination repair (HRR) in ES cells, but a minor HRR role in differentiated mouse cells.
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Fox JT, Lee KY, Myung K. Dynamic regulation of PCNA ubiquitylation/deubiquitylation. FEBS Lett 2011; 585:2780-5. [PMID: 21640107 DOI: 10.1016/j.febslet.2011.05.053] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 05/20/2011] [Accepted: 05/23/2011] [Indexed: 12/28/2022]
Abstract
Proliferating Cell Nuclear Antigen (PCNA) ubiquitylation plays a crucial role in maintaining genomic stability during DNA replication. DNA damage stalling the DNA replication fork induces PCNA ubiquitylation that activates DNA damage bypass to prevent the collapse of DNA replication forks that could potentially produce double-strand breaks and chromosomal rearrangements. PCNA ubiquitylation dictates the mode of bypass depending on the level of ubiquitylation; monoubiquitylation and polyubiquitylation activate error-prone translesion synthesis and error-free template switching, respectively. Due to the error-prone nature of DNA damage bypass, PCNA ubiquitylation needs to be tightly regulated. Here, we review the molecular mechanisms to remove ubiquitin from PCNA including the emerging role of USP1 and ELG1 in this fascinating process.
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Affiliation(s)
- Jennifer T Fox
- Genome Instability Section, Genetics and Molecular Biology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Abstract
Claspin is a mediator of the ATR-dependent DNA replication checkpoint in human cells and also promotes DNA replication fork progression and stability. Though Claspin has been shown to bind DNA and co-immunoprecipitate with other replication fork-associated proteins, the specific protein-protein and protein-DNA interactions that are important for Claspin function are not known. We therefore purified several domains of human Claspin and then tested for direct interactions of these fragments with several replication fork-associated proteins and with DNA. Our data show that the N terminus of Claspin binds to the replicative helicase co-factor Cdc45, the Timeless protein and a branched, replication fork-like DNA structure. In contrast, the C terminus of Claspin associates with DNA polymerase epsilon and Rad17-Replication Factor C (RFC). We conclude that multiple protein-DNA and protein-protein interactions may be important for Claspin function during DNA replication and DNA replication checkpoint signaling.
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Affiliation(s)
- Ozdemirhan Serçin
- University of North Carolina School of Medicine, Chapel Hill, NC USA
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Young JL, Koon EC, Kwong J, Welch WR, Muto MG, Berkowitz RS, Mok SC. Differential hRad17 expression by histologic subtype of ovarian cancer. J Ovarian Res 2011; 4:6. [PMID: 21450056 PMCID: PMC3077316 DOI: 10.1186/1757-2215-4-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 03/30/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In the search for unique ovarian cancer biomarkers, ovarian specific cDNA microarray analysis identified hRad17, a cell cycle checkpoint protein, as over-expressed in ovarian cancer. The aim of this study was to validate this expression. METHODS Immunohistochemistry was performed on 72 serous, 19 endometrioid, 10 clear cell, and 6 mucinous ovarian cancers, 9 benign ovarian tumors, and 6 normal ovarian tissue sections using an anti-hRad17 antibody. Western blot analysis and quantitative PCR were performed using cell lysates and total RNA prepared from 17 ovarian cancer cell lines and 6 normal ovarian epithelial cell cultures (HOSE). RESULTS Antibody staining confirmed upregulation of hRad17 in 49.5% of ovarian cancer cases. Immunohistochemistry demonstrated that only 42% of serous and 47% of endometrioid subtypes showed overexpression compared to 80% of clear cell and 100% of mucinous cancers. Western blot confirmed overexpression of hRad17 in cancer cell lines compared to HOSE. Quantitative PCR demonstrated an upregulation of hRad17 RNA by 1.5-7 fold. hRad17 RNA expression differed by subtype. CONCLUSIONS hRad17 is over-expressed in ovarian cancer. This over-expression varies by subtype suggesting a role in the pathogenesis of these types. Functional studies are needed to determine the potential role of this protein in ovarian cancer.
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Affiliation(s)
- Jennifer L Young
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Medical University of South Carolina, Charleston, SC, USA.
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Maniwa Y, Nishio W, Yoshimura M. Application of hRad9 in lung cancer treatment as a molecular marker and a molecular target. Thorac Cancer 2011; 2:7-15. [PMID: 27755837 DOI: 10.1111/j.1759-7714.2010.00036.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
DNA damage sensor proteins work as upstream components of the DNA damage checkpoint signaling pathways that are essential for cell cycle control and the induction of apoptosis. hRad9 is a member of a family of proteins that act as DNA damage sensors and plays an important role as an upstream regulator of checkpoint signaling. We clarified the significant accumulation of hRad9 in the nuclei of tumor cells in surgically-resected non-small-cell lung cancer (NSCLC) specimens and found the capacity to produce a functional hRad9 protein was intact in lung cancer cells. This finding suggested that hRad9 was a vital component in the pathways that lead to the survival and progression of NSCLC and suggested that hRad9 was a good candidate for a molecular target to control lung cancer cell growth. RNA interference targeting hRad9 was performed to examine this hypothesis. The impairment of the DNA damage checkpoint signaling pathway induced cancer cell death. hRad9 might be a novel molecular target for lung cancer treatment.
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Affiliation(s)
- Yoshimasa Maniwa
- Division of Thoracic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Wataru Nishio
- Division of Thoracic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masahiro Yoshimura
- Division of Thoracic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan
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Masai H, Tanaka T, Kohda D. Stalled replication forks: Making ends meet for recognition and stabilization. Bioessays 2010; 32:687-97. [DOI: 10.1002/bies.200900196] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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