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Usluer S, Galhuber M, Khanna Y, Bourgeois B, Spreitzer E, Michenthaler H, Prokesch A, Madl T. Disordered regions mediate the interaction of p53 and MRE11. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119654. [PMID: 38123020 DOI: 10.1016/j.bbamcr.2023.119654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 12/12/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023]
Abstract
The genome is frequently targeted by genotoxic agents, resulting in the formation of DNA scars. However, cells employ diverse repair mechanisms to restore DNA integrity. Among these processes, the Mre11-Rad50-Nbs1 complex detects double-strand breaks (DSBs) and recruits DNA damage response proteins such as ataxia-telangiectasia-mutated (ATM) kinase to DNA damage sites. ATM phosphorylates the transactivation domain (TAD) of the p53 tumor suppressor, which in turn regulates DNA repair, growth arrest, apoptosis, and senescence following DNA damage. The disordered glycine-arginine-rich (GAR) domain of double-strand break protein MRE11 (MRE11GAR) and its methylation are important for DSB repair, and localization to Promyelocytic leukemia nuclear bodies (PML-NBs). There is preliminary evidence that p53, PML protein, and MRE11 might co-localize and interact at DSB sites. To uncover the molecular details of these interactions, we aimed to identify the domains mediating the p53-MRE11 interaction and to elucidate the regulation of the p53-MRE11 interaction by post-translational modifications (PTMs) through a combination of biophysical techniques. We discovered that, in vitro, p53 binds directly to MRE11GAR mainly through p53TAD2 and that phosphorylation further enhances this interaction. Furthermore, we found that MRE11GAR methylation still allows for binding to p53. Overall, we demonstrated that p53 and MRE11 interaction is facilitated by disordered regions. We provide for the first time insight into the molecular details of the p53-MRE11 complex formation and elucidate potential regulatory mechanisms that will promote our understanding of the DNA damage response. Our findings suggest that PTMs regulate the p53-MRE11 interaction and subsequently their colocalization to PML-NBs upon DNA damage.
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Affiliation(s)
- Sinem Usluer
- Division of Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Austria; Research Unit Integrative Structural Biology, Medical University of Graz, Austria
| | - Markus Galhuber
- Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Austria
| | - Yukti Khanna
- Division of Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Austria; Research Unit Integrative Structural Biology, Medical University of Graz, Austria
| | - Benjamin Bourgeois
- Division of Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Austria; Research Unit Integrative Structural Biology, Medical University of Graz, Austria
| | - Emil Spreitzer
- Division of Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Austria; Research Unit Integrative Structural Biology, Medical University of Graz, Austria
| | - Helene Michenthaler
- Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Austria
| | - Andreas Prokesch
- Division of Cell Biology, Histology and Embryology, Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Austria; BioTechMed-Graz, Austria
| | - Tobias Madl
- Division of Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Austria; BioTechMed-Graz, Austria.
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Anwaar A, Varma AK, Baruah R. In Silico-Based Structural Evaluation to Categorize the Pathogenicity of Mutations Identified in the RAD Class of Proteins. ACS OMEGA 2023; 8:10266-10277. [PMID: 36969410 PMCID: PMC10034773 DOI: 10.1021/acsomega.2c07802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
RAD genes, known as double-strand break repair proteins, play a major role in maintaining the genomic integrity of a cell by carrying out essential DNA repair functions via double-strand break repair pathways. Mutations in the RAD class of proteins show high susceptibility to breast and ovarian cancers; however, adequate research on the mutations identified in these genes has not been extensively reported for their deleterious effects. Changes in the folding pattern of RAD proteins play an important role in protein-protein interactions and also functions. Missense mutations identified from four cancer databases, cBioPortal, COSMIC, ClinVar, and gnomAD, cause aberrant conformations, which may lead to faulty DNA repair mechanisms. It is therefore necessary to evaluate the effects of pathogenic mutations of RAD proteins and their subsequent role in breast and ovarian cancers. In this study, we have used eight computational prediction servers to analyze pathogenic mutations and understand their effects on the protein structure and function. A total of 5122 missense mutations were identified from four different cancer databases, of which 1165 were predicted to be pathogenic using at least five pathogenicity prediction servers. These mutations were characterized as high-risk mutations based on their location in the conserved domains and subsequently subjected to structural stability characterization. The mutations included in the present study were selected from clinically relevant mutants in breast cancer pedigrees. Comparative folding patterns and intra-atomic interaction results showed alterations in the structural behavior of RAD proteins, specifically RAD51C triggered by mutations G125V and L138F and RAD51D triggered by mutations S207L and E233G.
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Affiliation(s)
- Aaliya Anwaar
- Advanced
Centre for Treatment, Research and Education in Cancer, Kharghar, Navi Mumbai 410210, Maharashtra, India
| | - Ashok K. Varma
- Advanced
Centre for Treatment, Research and Education in Cancer, Kharghar, Navi Mumbai 410210, Maharashtra, India
- Homi
Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, Maharashtra, India
| | - Reshita Baruah
- Advanced
Centre for Treatment, Research and Education in Cancer, Kharghar, Navi Mumbai 410210, Maharashtra, India
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Lund Johansen E, Fribert Thusgaard C, Thomassen M, Eriksen Boonen S, Marie Jochumsen K. Germline Pathogenic Variants Associated with Ovarian Cancer: A Historical Overview. Gynecol Oncol Rep 2022; 44:101105. [DOI: 10.1016/j.gore.2022.101105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/02/2022] [Accepted: 11/06/2022] [Indexed: 11/09/2022] Open
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Pharmacological methods to transcriptionally modulate double-strand break DNA repair. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2019; 354:187-213. [PMID: 32475473 DOI: 10.1016/bs.ircmb.2019.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
There is much interest in targeting DNA repair pathways for use in cancer therapy, as the effectiveness of many therapeutic agents relies on their ability to cause damage to DNA, and deficiencies in DSB repair pathways can make cells more sensitive to specific cancer therapies. For example, defects in the double-strand break (DSB) pathways, non-homologous end joining (NHEJ) and homology-directed repair (HDR), induce sensitivity to radiation therapy and poly(ADP)-ribose polymerase (PARP) inhibitors, respectively. However, traditional approaches to inhibit DNA repair through small molecule inhibitors have often been limited by toxicity and poor bioavailability. This review identifies several pharmacologic manipulations that modulate DSB repair by reducing expression of DNA repair factors. A number of pathways have been identified that modulate activity of NHEJ and HDR through this mechanism, including growth and hormonal receptor signaling pathways as well as epigenetic modifiers. We also discuss the effects of anti-angiogenic therapy on DSB repair. Preclinically, these pharmacological manipulations of DNA repair factor expression have been shown to increase sensitivity to specific cancer therapies, including ionizing radiation and PARP inhibitors. When applicable, relevant clinical trials are discussed and areas for future study are identified.
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Bai Y, Wang W, Li S, Zhan J, Li H, Zhao M, Zhou XA, Li S, Li X, Huo Y, Shen Q, Zhou M, Zhang H, Luo J, Sung P, Zhu WG, Xu X, Wang J. C1QBP Promotes Homologous Recombination by Stabilizing MRE11 and Controlling the Assembly and Activation of MRE11/RAD50/NBS1 Complex. Mol Cell 2019; 75:1299-1314.e6. [PMID: 31353207 DOI: 10.1016/j.molcel.2019.06.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 05/06/2019] [Accepted: 06/18/2019] [Indexed: 12/27/2022]
Abstract
MRE11 nuclease forms a trimeric complex (MRN) with RAD50 and NBS1 and plays a central role in preventing genomic instability. When DNA double-strand breaks (DSBs) occur, MRN is quickly recruited to the damage site and initiates DNA end resection; accordingly, MRE11 must be tightly regulated to avoid inefficient repair or nonspecific resection. Here, we show that MRE11 and RAD50 form a complex (MRC) with C1QBP, which stabilizes MRE11/RAD50, while inhibiting MRE11 nuclease activity by preventing its binding to DNA or chromatin. Upon DNA damage, ATM phosphorylates MRE11-S676/S678 to quickly dissociate the MRC complex. Either excess or insufficient C1QBP impedes the recruitment of MRE11 to DSBs and impairs the DNA damage response. C1QBP is highly expressed in breast cancer and positively correlates with MRE11 expression, and the inhibition of C1QBP enhances tumor regression with chemotherapy. By influencing MRE11 at multiple levels, C1QBP is, thus, an important player in the DNA damage response.
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Affiliation(s)
- Yongtai Bai
- Department of Radiation Medicine, Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Weibin Wang
- Department of Radiation Medicine, Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Siyu Li
- Department of Radiation Medicine, Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Jun Zhan
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Hanxiao Li
- Department of Radiation Medicine, Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Meimei Zhao
- Department of Radiation Medicine, Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Xiao Albert Zhou
- Department of Radiation Medicine, Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Shiwei Li
- Department of Radiation Medicine, Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Xiaoman Li
- Department of Radiation Medicine, Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Yanfei Huo
- Department of Radiation Medicine, Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Qinjian Shen
- Department of Radiation Medicine, Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Mei Zhou
- Department of Radiation Medicine, Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Hongquan Zhang
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Jianyuan Luo
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Patrick Sung
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Wei-Guo Zhu
- Department of Biochemistry and Molecular Biology, Shenzhen University Health Science Center, Shenzhen, 518060, China
| | - Xingzhi Xu
- Department of Biochemistry and Molecular Biology, Shenzhen University Health Science Center, Shenzhen, 518060, China
| | - Jiadong Wang
- Department of Radiation Medicine, Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China.
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Chang HR, Munkhjargal A, Kim MJ, Park SY, Jung E, Ryu JH, Yang Y, Lim JS, Kim Y. The functional roles of PML nuclear bodies in genome maintenance. Mutat Res 2017; 809:99-107. [PMID: 28521962 DOI: 10.1016/j.mrfmmm.2017.05.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/28/2017] [Accepted: 05/04/2017] [Indexed: 02/07/2023]
Abstract
In the nucleus, there are several membraneless structures called nuclear bodies. Among them, promyelocytic leukemia nuclear bodies (PML-NBs) are involved in multiple genome maintenance pathways including the DNA damage response, DNA repair, telomere homeostasis, and p53-associated apoptosis. In response to DNA damage, PML-NBs are coalesced and divided by a fission mechanism, thus increasing their number. PML-NBs also play a role in repairing DNA double-strand breaks (DSBs) by homologous recombination (HR). Clinically, the dominant negative PML-RARα fusion protein expressed in acute promyelocytic leukemia (APL) inhibits the transactivation of downstream factors and disrupts PML function, revealing the tumor suppressor role of PML-NBs. All-trans retinoic acid and arsenic trioxide treatment has been implemented for promyelocytic leukemia to target the PML-RARα fusion protein. PML-NBs are associated with various factors implicated in genome maintenance, and are found at the sites of DNA damage. Their interaction with proteins such as p53 indicates that PML-NBs may play a significant role in apoptosis and cancer. Decades of research have revealed the importance of PML-NBs in diverse cellular pathways, yet the underlying molecular mechanisms and exact functions of PML-NBs remain elusive. In this review, PML protein modifications and the functional relevance of PML-NB and its associated factors in genome maintenance will be discussed.
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Affiliation(s)
- Hae Ryung Chang
- Department of Biological Sciences, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Anudari Munkhjargal
- Department of Biological Sciences, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Myung-Jin Kim
- Department of Biological Sciences, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Seon Young Park
- Department of Biological Sciences, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Eunyoung Jung
- Department of Biological Sciences, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Jae-Ha Ryu
- Research Center for Cell Fate Control, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Young Yang
- Department of Biological Sciences, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Jong-Seok Lim
- Department of Biological Sciences, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Yonghwan Kim
- Department of Biological Sciences, Sookmyung Women's University, Seoul 04310, Republic of Korea.
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Barfeld SJ, Urbanucci A, Itkonen HM, Fazli L, Hicks JL, Thiede B, Rennie PS, Yegnasubramanian S, DeMarzo AM, Mills IG. c-Myc Antagonises the Transcriptional Activity of the Androgen Receptor in Prostate Cancer Affecting Key Gene Networks. EBioMedicine 2017; 18:83-93. [PMID: 28412251 PMCID: PMC5405195 DOI: 10.1016/j.ebiom.2017.04.006] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 04/04/2017] [Indexed: 12/25/2022] Open
Abstract
Prostate cancer (PCa) is the most common non-cutaneous cancer in men. The androgen receptor (AR), a ligand-activated transcription factor, constitutes the main drug target for advanced cases of the disease. However, a variety of other transcription factors and signaling networks have been shown to be altered in patients and to influence AR activity. Amongst these, the oncogenic transcription factor c-Myc has been studied extensively in multiple malignancies and elevated protein levels of c-Myc are commonly observed in PCa. Its impact on AR activity, however, remains elusive. In this study, we assessed the impact of c-Myc overexpression on AR activity and transcriptional output in a PCa cell line model and validated the antagonistic effect of c-MYC on AR-targets in patient samples. We found that c-Myc overexpression partially reprogrammed AR chromatin occupancy and was associated with altered histone marks distribution, most notably H3K4me1 and H3K27me3. We found c-Myc and the AR co-occupy a substantial number of binding sites and these exhibited enhancer-like characteristics. Interestingly, c-Myc overexpression antagonised clinically relevant AR target genes. Therefore, as an example, we validated the antagonistic relationship between c-Myc and two AR target genes, KLK3 (alias PSA, prostate specific antigen), and Glycine N-Methyltransferase (GNMT), in patient samples. Our findings provide unbiased evidence that MYC overexpression deregulates the AR transcriptional program, which is thought to be a driving force in PCa. c-MYC and AR share one third of chromatin binding with enhancer-like features. c-MYC can repress the expression of a subset prostate cancer biomarkers, including PSA. c-MYC and AR antagonize the expression of, Glycine N-Methyltransferase (GNMT), responsible for sarcosine biosynthesis.
Prostate cancer is a heterogeneous disease. The most frequently used biomarker in clinical setting, a well described androgen receptor target gene, PSA, still performs poorly in stratifying patients at real risk of death due to the disease. Despite this, therapeutic approaches focus on suppressing androgen receptor signaling. However, this is only one of the recurrent alterations found in patients. This study focuses on c-MYC and the effects of its deregulation in advanced prostate cancer. We find that there is an inverse relationship between established biomarkers expression, including PSA. This inverse relationship could be used in clinics to select beneficial therapeutic approaches for a subset of prostate cancer cases.
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Affiliation(s)
- Stefan J Barfeld
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership, University of Oslo, Oslo, Norway.
| | - Alfonso Urbanucci
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership, University of Oslo, Oslo, Norway; Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.
| | - Harri M Itkonen
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership, University of Oslo, Oslo, Norway
| | - Ladan Fazli
- The Vancouver Prostate Centre, University of British Columbia, Canada
| | | | - Bernd Thiede
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Paul S Rennie
- The Vancouver Prostate Centre, University of British Columbia, Canada
| | | | - Angelo M DeMarzo
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Ian G Mills
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership, University of Oslo, Oslo, Norway; Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway; PCUK/Movember Centre of Excellence, CCRCB, Queen's University, Belfast, UK.
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Personalised Medicine: Genome Maintenance Lessons Learned from Studies in Yeast as a Model Organism. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1007:157-178. [PMID: 28840557 DOI: 10.1007/978-3-319-60733-7_9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Yeast research has been tremendously contributing to the understanding of a variety of molecular pathways due to the ease of its genetic manipulation, fast doubling time as well as being cost-effective. The understanding of these pathways did not only help scientists learn more about the cellular functions but also assisted in deciphering the genetic and cellular defects behind multiple diseases. Hence, yeast research not only opened the doors for transforming basic research into applied research, but also paved the roads for improving diagnosis and innovating personalized therapy of different diseases. In this chapter, we discuss how yeast research has contributed to understanding major genome maintenance pathways such as the S-phase checkpoint activation pathways, repair via homologous recombination and non-homologous end joining as well as topoisomerases-induced protein linked DNA breaks repair. Defects in these pathways lead to neurodegenerative diseases and cancer. Thus, the understanding of the exact genetic defects underlying these diseases allowed the development of personalized medicine, improving the diagnosis and treatment and overcoming the detriments of current conventional therapies such as the side effects, toxicity as well as drug resistance.
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Kostianets O, Shyyan M, Antoniuk SV, Filonenko V, Kiyamova R. Panel of SEREX-defined antigens for breast cancer autoantibodies profile detection. Biomarkers 2016; 22:149-156. [DOI: 10.1080/1354750x.2016.1252952] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Olga Kostianets
- Department of Cell Signaling, Institute of Molecular Biology and Genetics, NAS of Ukraine, Kyiv, Ukraine
| | - Maksym Shyyan
- Department of Cell Signaling, Institute of Molecular Biology and Genetics, NAS of Ukraine, Kyiv, Ukraine
| | | | - Valeriy Filonenko
- Department of Cell Signaling, Institute of Molecular Biology and Genetics, NAS of Ukraine, Kyiv, Ukraine
| | - Ramziya Kiyamova
- Department of Cell Signaling, Institute of Molecular Biology and Genetics, NAS of Ukraine, Kyiv, Ukraine
- Kazan Volga Region Federal University, Institute of Fundamental Medicine and Biology, Kazan, Russian Federation
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10
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Breitkopf SB, Yuan M, Helenius KP, Lyssiotis CA, Asara JM. Triomics Analysis of Imatinib-Treated Myeloma Cells Connects Kinase Inhibition to RNA Processing and Decreased Lipid Biosynthesis. Anal Chem 2015; 87:10995-1006. [PMID: 26434776 PMCID: PMC5585869 DOI: 10.1021/acs.analchem.5b03040] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The combination of metabolomics, lipidomics, and phosphoproteomics that incorporates triple stable isotope labeling by amino acids in cell culture (SILAC) protein labeling, as well as (13)C in vivo metabolite labeling, was demonstrated on BCR-ABL-positive H929 multiple myeloma cells. From 11 880 phosphorylation sites, we confirm that H929 cells are primarily signaling through the BCR-ABL-ERK pathway, and we show that imatinib treatment not only downregulates phosphosites in this pathway but also upregulates phosphosites on proteins involved in RNA expression. Metabolomics analyses reveal that BCR-ABL-ERK signaling in H929 cells drives the pentose phosphate pathway (PPP) and RNA biosynthesis, where pathway inhibition via imatinib results in marked PPP impairment and an accumulation of RNA nucleotides and negative regulation of mRNA. Lipidomics data also show an overall reduction in lipid biosynthesis and fatty acid incorporation with a significant decrease in lysophospholipids. RNA immunoprecipitation studies confirm that RNA degradation is inhibited with short imatinib treatment and transcription is inhibited upon long imatinib treatment, validating the triomics results. These data show the utility of combining mass spectrometry-based "-omics" technologies and reveals that kinase inhibitors may not only downregulate phosphorylation of their targets but also induce metabolic events via increased phosphorylation of other cellular components.
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Affiliation(s)
- Susanne B. Breitkopf
- Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, United States
- Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Min Yuan
- Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, United States
| | - Katja P. Helenius
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Costas A. Lyssiotis
- Department of Molecular and Integrative Physiology and Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - John M. Asara
- Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, United States
- Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, United States
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Cejka P. DNA End Resection: Nucleases Team Up with the Right Partners to Initiate Homologous Recombination. J Biol Chem 2015; 290:22931-8. [PMID: 26231213 DOI: 10.1074/jbc.r115.675942] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The repair of DNA double-strand breaks by homologous recombination commences by nucleolytic degradation of the 5'-terminated strand of the DNA break. This leads to the formation of 3'-tailed DNA, which serves as a substrate for the strand exchange protein Rad51. The nucleoprotein filament then invades homologous DNA to drive template-directed repair. In this review, I discuss mainly the mechanisms of DNA end resection in Saccharomyces cerevisiae, which includes short-range resection by Mre11-Rad50-Xrs2 and Sae2, as well as processive long-range resection by Sgs1-Dna2 or Exo1 pathways. Resection mechanisms are highly conserved between yeast and humans, and analogous machineries are found in prokaryotes as well.
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Affiliation(s)
- Petr Cejka
- From the Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
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12
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Brown JS, Jackson SP. Ubiquitylation, neddylation and the DNA damage response. Open Biol 2015; 5:150018. [PMID: 25833379 PMCID: PMC4422126 DOI: 10.1098/rsob.150018] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/09/2015] [Indexed: 12/19/2022] Open
Abstract
Failure of accurate DNA damage sensing and repair mechanisms manifests as a variety of human diseases, including neurodegenerative disorders, immunodeficiency, infertility and cancer. The accuracy and efficiency of DNA damage detection and repair, collectively termed the DNA damage response (DDR), requires the recruitment and subsequent post-translational modification (PTM) of a complex network of proteins. Ubiquitin and the ubiquitin-like protein (UBL) SUMO have established roles in regulating the cellular response to DNA double-strand breaks (DSBs). A role for other UBLs, such as NEDD8, is also now emerging. This article provides an overview of the DDR, discusses our current understanding of the process and function of PTM by ubiquitin and NEDD8, and reviews the literature surrounding the role of ubiquitylation and neddylation in DNA repair processes, focusing particularly on DNA DSB repair.
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Affiliation(s)
- Jessica S Brown
- The Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
| | - Stephen P Jackson
- The Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
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13
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MR (Mre11-Rad50) complex in Giardia duodenalis: In vitro characterization and its response upon DNA damage. Biochimie 2015; 111:45-57. [DOI: 10.1016/j.biochi.2015.01.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Accepted: 01/17/2015] [Indexed: 11/24/2022]
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14
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Laffitte MCN, Genois MM, Mukherjee A, Légaré D, Masson JY, Ouellette M. Formation of linear amplicons with inverted duplications in Leishmania requires the MRE11 nuclease. PLoS Genet 2014; 10:e1004805. [PMID: 25474106 PMCID: PMC4256157 DOI: 10.1371/journal.pgen.1004805] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 10/06/2014] [Indexed: 11/22/2022] Open
Abstract
Extrachromosomal DNA amplification is frequent in the protozoan parasite Leishmania selected for drug resistance. The extrachromosomal amplified DNA is either circular or linear, and is formed at the level of direct or inverted homologous repeated sequences that abound in the Leishmania genome. The RAD51 recombinase plays an important role in circular amplicons formation, but the mechanism by which linear amplicons are formed is unknown. We hypothesized that the Leishmania infantum DNA repair protein MRE11 is required for linear amplicons following rearrangements at the level of inverted repeats. The purified LiMRE11 protein showed both DNA binding and exonuclease activities. Inactivation of the LiMRE11 gene led to parasites with enhanced sensitivity to DNA damaging agents. The MRE11−/− parasites had a reduced capacity to form linear amplicons after drug selection, and the reintroduction of an MRE11 allele led to parasites regaining their capacity to generate linear amplicons, but only when MRE11 had an active nuclease activity. These results highlight a novel MRE11-dependent pathway used by Leishmania to amplify portions of its genome to respond to a changing environment. Extrachromosomal DNA amplification is frequent in the human protozoan parasite Leishmania when challenged with drug or other stressful conditions. DNA amplicons, either circular or linear, are formed by recombination between direct or inverted repeats spread throughout the genome of the parasite. The recombinase RAD51 is involved in the formation of circular amplicons, but the mechanism by which linear amplicons are formed is still unknown in this parasite. Studies in other organisms have provided some evidence that a DNA break is required for linear amplifications, and that the DNA repair protein MRE11 can be involved in this process. In this work, we present our biochemical, cellular and molecular characterization of the Leishmania infantum MRE11 orthologue and provide evidence that this nuclease is involved in the formation of linear amplicons in Leishmania. Our results highlight a novel MRE11-dependent pathway used by Leishmania to amplify portions of its genome to respond to a changing environment.
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Affiliation(s)
| | - Marie-Michelle Genois
- Centre de Recherche en Infectiologie du CHU de Québec, Quebec City, Québec, Canada
- Genome Stability Laboratory, CHU de Quebec Research Center, HDQ Pavillon, Oncology Axis, Quebec City, Québec, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University, Quebec City, Québec, Canada
| | - Angana Mukherjee
- Centre de Recherche en Infectiologie du CHU de Québec, Quebec City, Québec, Canada
| | - Danielle Légaré
- Centre de Recherche en Infectiologie du CHU de Québec, Quebec City, Québec, Canada
| | - Jean-Yves Masson
- Genome Stability Laboratory, CHU de Quebec Research Center, HDQ Pavillon, Oncology Axis, Quebec City, Québec, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University, Quebec City, Québec, Canada
| | - Marc Ouellette
- Centre de Recherche en Infectiologie du CHU de Québec, Quebec City, Québec, Canada
- * E-mail:
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15
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Rojowska A, Lammens K, Seifert FU, Direnberger C, Feldmann H, Hopfner KP. Structure of the Rad50 DNA double-strand break repair protein in complex with DNA. EMBO J 2014; 33:2847-59. [PMID: 25349191 DOI: 10.15252/embj.201488889] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The Mre11-Rad50 nuclease-ATPase is an evolutionarily conserved multifunctional DNA double-strand break (DSB) repair factor. Mre11-Rad50's mechanism in the processing, tethering, and signaling of DSBs is unclear, in part because we lack a structural framework for its interaction with DNA in different functional states. We determined the crystal structure of Thermotoga maritima Rad50(NBD) (nucleotide-binding domain) in complex with Mre11(HLH) (helix-loop-helix domain), AMPPNP, and double-stranded DNA. DNA binds between both coiled-coil domains of the Rad50 dimer with main interactions to a strand-loop-helix motif on the NBD. Our analysis suggests that this motif on Rad50 does not directly recognize DNA ends and binds internal sites on DNA. Functional studies reveal that DNA binding to Rad50 is not critical for DNA double-strand break repair but is important for telomere maintenance. In summary, we provide a structural framework for DNA binding to Rad50 in the ATP-bound state.
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Affiliation(s)
- Anna Rojowska
- Department of Biochemistry and Gene Center, Ludwig-Maximilians-University, Munich, Germany
| | - Katja Lammens
- Department of Biochemistry and Gene Center, Ludwig-Maximilians-University, Munich, Germany
| | - Florian U Seifert
- Department of Biochemistry and Gene Center, Ludwig-Maximilians-University, Munich, Germany
| | - Carolin Direnberger
- Department of Biochemistry and Gene Center, Ludwig-Maximilians-University, Munich, Germany
| | - Heidi Feldmann
- Department of Biochemistry and Gene Center, Ludwig-Maximilians-University, Munich, Germany
| | - Karl-Peter Hopfner
- Department of Biochemistry and Gene Center, Ludwig-Maximilians-University, Munich, Germany Center for Integrated Protein Sciences, Munich, Germany
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16
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Schröder-Heurich B, Wieland B, Lavin MF, Schindler D, Dörk T. Protective role of RAD50 on chromatin bridges during abnormal cytokinesis. FASEB J 2013; 28:1331-41. [PMID: 24344331 DOI: 10.1096/fj.13-236984] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Faithful chromosome segregation is required for preserving genomic integrity. Failure of this process may entail chromatin bridges preventing normal cytokinesis. To test whether RAD50, a protein normally involved in DNA double-strand break repair, is involved in abnormal cytokinesis and formation of chromatin bridges, we used immunocytochemical and protein interaction assays. RAD50 localizes to chromatin bridges during aberrant cytokinesis and subsequent stages of the cell cycle, either decorating the entire bridge or focally accumulating at the midbody zone. Ionizing radiation led to an ∼4-fold increase in the rate of chromatin bridges in an ataxia telangiectatica mutated (ATM)-dependent manner in human RAD50-proficient fibroblasts but not in RAD50-deficient cells. Cells with a RAD50-positive chromatin bridge were able to continue cell cycling and to progress through S phase (44%), whereas RAD50 knockdown caused a deficiency in chromatin bridges as well as an ∼4-fold prolonged duration of mitosis. RAD50 colocalized and directly interacted with Aurora B kinase and phospho-histone H3, and Aurora B kinase inhibition led to a deficiency in RAD50-positive bridges. Based on these observations, we propose that RAD50 is a crucial factor for the stabilization and shielding of chromatin bridges. Our study provides evidence for a hitherto unknown role of RAD50 in abnormal cytokinesis.
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Affiliation(s)
- Bianca Schröder-Heurich
- 1Hannover Medical School, Gynaecology Research Unit (OE 6411), Carl-Neuberg-Str. 1, D-30625 Hannover, Germany.
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17
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Kostianets O, Antoniuk S, Filonenko V, Kiyamova R. Immunohistochemical analysis of medullary breast carcinoma autoantigens in different histological types of breast carcinomas. Diagn Pathol 2012; 7:161. [PMID: 23181716 PMCID: PMC3533517 DOI: 10.1186/1746-1596-7-161] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 11/14/2012] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND On the past decade a plethora of investigations were directed on identification of molecules involved in breast tumorogenesis, which could represent a powerful tool for monitoring, diagnostics and treatment of this disease. In current study we analyzed six previously identified medullary breast carcinoma autoantigens including LGALS3BP, RAD50, FAM50A, RBPJ, PABPC4, LRRFIP1 with cancer restricted serological profile in different histological types of breast cancer. METHODS Semi-quantitative immunohistochemical analysis of 20 tissue samples including medullary breast carcinoma, invasive ductal carcinoma, invasive lobular carcinoma and non-cancerous tissues obtained from patients with fibrocystic disease (each of five) was performed using specifically generated polyclonal antibodies. Differences in expression patterns were evaluated considering percent of positively stained cells, insensitivity of staining and subcellular localization in cells of all tissue samples. RESULTS All 6 antigens predominantly expressed in the most cells of all histological types of breast tumors and non-cancerous tissues with slight differences in intensity of staining and subcellular localization. The most significant differences in expression pattern were revealed for RAD50 and LGALS3BP in different histological types of breast cancer and for PABPC4 and FAM50A antigens in immune cells infiltrating breast tumors. CONCLUSIONS This pilot study made possible to select 4 antigens LGALS3BP, RAD50, PABPC4, and FAM50A as promising candidates for more comprehensive research as potential molecular markers for breast cancer diagnostics and therapy. VIRTUAL SLIDES The virtual slides' for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1860649350796892.
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MESH Headings
- Acid Anhydride Hydrolases
- Adult
- Aged
- Antigens, Neoplasm/analysis
- Autoantigens/analysis
- Biomarkers, Tumor/analysis
- Blood Proteins/analysis
- Breast Neoplasms/classification
- Breast Neoplasms/immunology
- Breast Neoplasms/pathology
- Carcinoma, Ductal, Breast/classification
- Carcinoma, Ductal, Breast/immunology
- Carcinoma, Ductal, Breast/pathology
- Carcinoma, Lobular/classification
- Carcinoma, Lobular/immunology
- Carcinoma, Lobular/pathology
- Carcinoma, Medullary/classification
- Carcinoma, Medullary/immunology
- Carcinoma, Medullary/pathology
- Carrier Proteins/analysis
- DNA Repair Enzymes/analysis
- DNA-Binding Proteins/analysis
- Female
- Fibrocystic Breast Disease/immunology
- Fibrocystic Breast Disease/pathology
- Glycoproteins/analysis
- Humans
- Immunohistochemistry
- Middle Aged
- Nuclear Proteins/analysis
- Pilot Projects
- Poly(A)-Binding Proteins/analysis
- RNA-Binding Proteins
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Affiliation(s)
- Olga Kostianets
- Department of Cell Signaling, Institute of Molecular Biology and Genetics, NAS of Ukraine, 150, Zabolotnogo str., Kyiv, Ukraine
- Educational and Scientific Centre “Institute of Biology”, Taras Shevchenko National University of Kyiv, 64, Volodymyrs’ka Str., Kyiv, Ukraine
| | - Stepan Antoniuk
- Dnipropetrovsk Clinical Oncological Center, Dnipropetrovsk, Ukraine
| | - Valeriy Filonenko
- Department of Cell Signaling, Institute of Molecular Biology and Genetics, NAS of Ukraine, 150, Zabolotnogo str., Kyiv, Ukraine
| | - Ramziya Kiyamova
- Department of Cell Signaling, Institute of Molecular Biology and Genetics, NAS of Ukraine, 150, Zabolotnogo str., Kyiv, Ukraine
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Kostianets O, Shyian M, Sergiy D, Antoniuk S, Gout I, Filonenko V, Kiyamova R. Serological Analysis of SEREX-Defined Medullary Breast Carcinoma-Associated Antigens. Cancer Invest 2012; 30:519-27. [DOI: 10.3109/07357907.2012.697231] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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19
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Park YB, Chae J, Kim YC, Cho Y. Crystal structure of human Mre11: understanding tumorigenic mutations. Structure 2012; 19:1591-602. [PMID: 22078559 DOI: 10.1016/j.str.2011.09.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Revised: 09/09/2011] [Accepted: 09/10/2011] [Indexed: 11/29/2022]
Abstract
Mre11 plays an important role in repairing damaged DNA by cleaving broken ends and by providing a platform for other DNA repair proteins. Various Mre11 mutations have been identified in several types of cancer. We have determined the crystal structure of the human Mre11 core (hMre11), which contains the nuclease and capping domains. hMre11 dimerizes through the interfaces between loop β3-α3 from one Mre11 and loop β4-β5 from another Mre11, and between loop α2-β3 from one Mre11 and helices α2 and α3 from another Mre11, and assembles into a completely different dimeric architecture compared with bacterial or archaeal Mre11 homologs. Nbs1 binds to the region containing loop α2-β3 which participates in dimerization. The hMre11 structure in conjunction with biochemical analyses reveals that many tumorigenic mutations are primarily associated with Nbs1 binding and partly with nuclease activities, providing a framework for understanding how mutations inactivate Mre11.
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Affiliation(s)
- Young Bong Park
- Department of Life Science, Pohang University of Science and Technology, Pohang 790-784, South Korea
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20
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Pérez R, Cuadrado A, Chen IP, Puchta H, Jouve N, De Bustos A. The Rad50 genes of diploid and polyploid wheat species. Analysis of homologue and homoeologue expression and interactions with Mre11. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2011; 122:251-262. [PMID: 20827456 DOI: 10.1007/s00122-010-1440-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 08/25/2010] [Indexed: 05/29/2023]
Abstract
The MRN complex plays a central role in the DNA repair pathways of eukaryotic cells and takes part in many other processes, including cell cycle checkpoint signalling, meiosis, DNA replication and telomere maintenance. This complex is formed by the interaction of the products of the Mre11, Rad50 and Nbs1 genes. This paper reports the molecular characterization, expression and interactions of the Rad50 gene in several wheat species with different levels of ploidy. The homoeologous Rad50 wheat genes were found to show a high level of conservation. Most of the RAD50 domains and motifs previously described in other species were also present in wheat RAD50; these proteins are therefore likely to have similar functions. Interactions between the RAD50 wheat proteins and their MRE11 counterparts in the MRN complex were observed. The level of expression of Rad50 in each of the species examined was determined and compared with those previously reported for the Mre11 genes. In some cases similar levels of expression were seen, as expected. The expression of the RAD50 homoeologous genes was assessed in two polyploid wheat species using quantitative PCR. In both cases, an overexpression of the Rad50B gene was detected. Although the results indicate the maintenance of function of these species' three homoeologous Rad50 genes, the biased expression of Rad50B might indicate ongoing silencing of one or both other homoeologues in polyploid wheat. To assess the consequences of such silencing on the formation of the MRN complex, the interactions between individual homoeologues of Rad50 and their genomic counterpart Mre11 genes were examined. The results indicate the inexistence of genomic specificity in the interactions between these genes. This would guarantee the formation of an MRN complex in wheat.
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Affiliation(s)
- R Pérez
- Department of Cell Biology and Genetics, University of Alcalá, Alcalá de Henares, Spain
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21
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Gerashchenko BI, Gooding G, Dynlacht JR. Hyperthermia alters the interaction of proteins of the Mre11 complex in irradiated cells. Cytometry A 2010; 77:940-52. [PMID: 21290468 PMCID: PMC3075327 DOI: 10.1002/cyto.a.20955] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Revised: 07/02/2010] [Accepted: 07/05/2010] [Indexed: 12/13/2022]
Abstract
Radiosensitization of mammalian cells by heat is believed to involve the inhibition of repair of DNA double-strand breaks (DSBs). The Mre11 complex (composed of Mre11, Rad50, and Nbs1) is involved in DSB repair and forms foci at sites of radiation-induced DSBs. Heat induces the translocation of a significant amount of Mre11, Rad50, and Nbs1 from the nucleus to the cytoplasm, but little is known about how heat affects the integrity of the proteins still remaining in nuclei, or alters kinetics of formation/disappearance of DNA repair foci in heated, irradiated cells. Here, we show that hyperthermia alters the interaction between proteins of the Mre11 complex in irradiated human melanoma cells and inhibits the formation of repair foci. At various times after X-irradiation and/or heating (2 h at 41.5 or 42.5 °C), the cells were fixed and stained for Mre11, Rad50, and Nbs1. Colocalization of proteins and formation and disappearance of nuclear foci in heated and/or irradiated cells, determined using confocal microscopy, were compared. In heated, irradiated cells, focus formation was inhibited for 2-8 h, and colocalization of the proteins of the Mre11 complex was reduced for 12-24 h post-treatment. Colocalization was recovered in irradiated cells within 24 h after heating at 41.5 °C, but was inhibited longer after heating at 42.5 °C. The decreased colocalization in heated, irradiated cells suggests that there is a decrease in protein interaction, and Mre11 complexes in nuclei disassemble after heating. Such changes could be involved, at least in part, in heat radiosensitization and inhibition of DSB repair. Also, the kinetics of disassembly and reassembly of Mre11 complexes appears to be dependent upon treatment temperature.
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Affiliation(s)
- Bogdan I. Gerashchenko
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Radiobiology and Ecology, R.E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology, Kyiv 03022, Ukraine
| | - Gerirose Gooding
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Joseph R. Dynlacht
- Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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22
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Lamarche BJ, Orazio NI, Weitzman MD. The MRN complex in double-strand break repair and telomere maintenance. FEBS Lett 2010; 584:3682-95. [PMID: 20655309 DOI: 10.1016/j.febslet.2010.07.029] [Citation(s) in RCA: 306] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 07/16/2010] [Accepted: 07/19/2010] [Indexed: 10/25/2022]
Abstract
Genomes are subject to constant threat by damaging agents that generate DNA double-strand breaks (DSBs). The ends of linear chromosomes need to be protected from DNA damage recognition and end-joining, and this is achieved through protein-DNA complexes known as telomeres. The Mre11-Rad50-Nbs1 (MRN) complex plays important roles in detection and signaling of DSBs, as well as the repair pathways of homologous recombination (HR) and non-homologous end-joining (NHEJ). In addition, MRN associates with telomeres and contributes to their maintenance. Here, we provide an overview of MRN functions at DSBs, and examine its roles in telomere maintenance and dysfunction.
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Affiliation(s)
- Brandon J Lamarche
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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23
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Thomson TC, Fitzpatrick KE, Johnson J. Intrinsic and extrinsic mechanisms of oocyte loss. Mol Hum Reprod 2010; 16:916-27. [PMID: 20651035 DOI: 10.1093/molehr/gaq066] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A great deal of evolutionary conservation has been found in the control of oocyte development, from invertebrates to women. However, little is known of mechanisms that control oocyte loss over time. Oocyte loss is often assumed to be a result of oocyte-intrinsic deficiencies or damage. In fruit flies, starvation results in halted oocyte production by germline stem cells and induces oocyte loss midway through development. When we fed wild-type flies the bacterial compound Rapamycin (RAP) to mimic starvation, production of new oocytes continued, but mid-stage loss sterilized the animals. Surprisingly, follicle cell invasion and phagocytosis of the oocyte preceded any signs of germ cell death. RAP-induced egg chamber loss was prevented when RAP receptor FKBP12 was knocked down specifically in follicle cells. Oogenesis continued past the mid-stages, and these mutants continued to lay embryos that could develop into normal adults. Hence, intact healthy oocytes can be destroyed by somatic cells responding to extrinsic stimuli. We termed this process inducible somatic oocyte destruction. RAP treatment of mouse follicles in vitro resulted in phagocytic uptake of the oocyte by granulosa cells as seen in flies. We hypothesize that extrinsic modes of oocyte loss occur in mammals.
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Affiliation(s)
- Travis C Thomson
- Department of Obstetrics, Gynecology & Reproductive Sciences, Division of Reproductive Endocrinology and Infertility, Yale School of Medicine, 333 Cedar Street FMB 329F, New Haven, CT 06520, USA
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24
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Kobayashi J, Kato A, Ota Y, Ohba R, Komatsu K. Bisbenzamidine derivative, pentamidine represses DNA damage response through inhibition of histone H2A acetylation. Mol Cancer 2010; 9:34. [PMID: 20144237 PMCID: PMC2831819 DOI: 10.1186/1476-4598-9-34] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Accepted: 02/09/2010] [Indexed: 11/17/2022] Open
Abstract
Background MRE11 is an important nuclease which functions in the end-resection step of homologous recombination (HR) repair of DNA double-strand breaks (DSBs). As MRE11-deficient ATLD cells exhibit hyper radio-sensitivity and impaired DSB repair, MRE11 inhibitors could possibly function as potent radio-sensitizers. Therefore, we investigated whether a bisbenzamidine derivative, pentamidine, which can inhibit endoexonuclease activity, might influence DSB-induced damage responses via inhibition of MRE11. Results We first clarified that pentamidine inhibited MRE11 nuclease activity and also reduced ATM kinase activity in vitro. Pentamidine increased the radio-sensitivity of HeLa cells, suggesting that this compound could possibly influence DNA damage response factors in vivo. Indeed, we found that pentamidine reduced the accumulation of γ-H2AX, NBS1 and phospho-ATM at the sites of DSBs. Furthermore, pentamidine decreased HR activity in vivo. Pentamidine was found to inhibit the acetylation of histone H2A which could contribute both to inhibition of IR-induced focus formation and HR repair. These results suggest that pentamidine might exert its effects by inhibiting histone acetyltransferases. We found that pentamidine repressed the activity of Tip60 acetyltransferase which is known to acetylate histone H2A and that knockdown of Tip60 by siRNA reduced HR activity. Conclusion These results indicate that inhibition of Tip60 as well as hMRE11 nuclease by pentamidine underlies the radiosensitizing effects of this compound making it an excellent sensitizer for radiotherapy or chemotherapy.
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Affiliation(s)
- Junya Kobayashi
- Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University, Kyoto 606-8501, Japan.
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25
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Krishnamurthy M, Tadesse S, Rothmaier K, Graumann PL. A novel SMC-like protein, SbcE (YhaN), is involved in DNA double-strand break repair and competence in Bacillus subtilis. Nucleic Acids Res 2009; 38:455-66. [PMID: 19906728 PMCID: PMC2811018 DOI: 10.1093/nar/gkp909] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Bacillus subtilis and most Gram positive bacteria possess four SMC like proteins: SMC, SbcC, RecN and the product of the yhaN gene, termed SbcE. SbcE is most similar to SbcC but contains a unique central domain. We show that SbcE plays a role during transformation in competent cells and in DNA double-strand break (DSB) repair. The phenotypes were strongly exacerbated by the additional deletion of recN or of sbcC, suggesting that all three proteins act upstream of RecA and provide distinct avenues for presynapsis. SbcE accumulated at the cell poles in competent cells, and localized as a discrete focus on the nucleoids in 10% of growing cells. This number moderately increased after treatment with DNA damaging agents and in the absence of RecN or of SbcC. Damage-induced foci of SbcE arose early after induction of DNA damage and rarely colocalized with the replication machinery. Our work shows that SMC-like proteins in B. subtilis play roles at different subcellular sites during DNA repair. SbcC operates at breaks occurring at the replication machinery, whereas RecN and SbcE function mainly, but not exclusively, at DSBs arising elsewhere on the chromosome. In agreement with this idea, we found that RecN-YFP damage-induced assemblies also arise in the absence of ongoing replication.
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26
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Chang L, Liu Y, Zhu B, Li Y, Hua H, Wang Y, Zhang J, Jiang Z, Wang Z. High expression of the circadian gene mPer2 diminishes the radiosensitivity of NIH 3T3 cells. Braz J Med Biol Res 2009; 42:882-91. [DOI: 10.1590/s0100-879x2009005000022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Accepted: 07/22/2009] [Indexed: 01/17/2023] Open
Affiliation(s)
| | | | - B. Zhu
- Sichuan University, China
| | - Y. Li
- Sichuan University, China
| | - H. Hua
- Sichuan University, China
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27
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PARP is activated at stalled forks to mediate Mre11-dependent replication restart and recombination. EMBO J 2009; 28:2601-15. [PMID: 19629035 DOI: 10.1038/emboj.2009.206] [Citation(s) in RCA: 473] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Accepted: 06/25/2009] [Indexed: 12/20/2022] Open
Abstract
If replication forks are perturbed, a multifaceted response including several DNA repair and cell cycle checkpoint pathways is activated to ensure faithful DNA replication. Here, we show that poly(ADP-ribose) polymerase 1 (PARP1) binds to and is activated by stalled replication forks that contain small gaps. PARP1 collaborates with Mre11 to promote replication fork restart after release from replication blocks, most likely by recruiting Mre11 to the replication fork to promote resection of DNA. Both PARP1 and PARP2 are required for hydroxyurea-induced homologous recombination to promote cell survival after replication blocks. Together, our data suggest that PARP1 and PARP2 detect disrupted replication forks and attract Mre11 for end processing that is required for subsequent recombination repair and restart of replication forks.
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28
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Abuzeid WM, Jiang X, Shi G, Wang H, Paulson D, Araki K, Jungreis D, Carney J, O’Malley BW, Li D. Molecular disruption of RAD50 sensitizes human tumor cells to cisplatin-based chemotherapy. J Clin Invest 2009; 119:1974-85. [PMID: 19487811 PMCID: PMC2701852 DOI: 10.1172/jci33816] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Accepted: 03/19/2009] [Indexed: 11/17/2022] Open
Abstract
Platinum-based drugs that induce DNA damage are commonly used first-line chemotherapy agents for testicular, bladder, head and neck, lung, esophageal, stomach, and ovarian cancers. The inherent resistance of tumors to DNA damage often limits the therapeutic efficacy of these agents, such as cisplatin. An enhanced DNA repair and telomere maintenance response by the Mre11/Rad50/Nbs1 (MRN) complex is critical in driving this chemoresistance. We hypothesized therefore that the targeted impairment of native cellular MRN function could sensitize tumor cells to cisplatin. To test this, we designed what we believe to be a novel dominant-negative adenoviral vector containing a mutant RAD50 gene that significantly downregulated MRN expression and markedly disrupted MRN function in human squamous cell carcinoma cells. A combination of cisplatin and mutant RAD50 therapy produced significant tumor cytotoxicity in vitro, with a corresponding increase in DNA damage and telomere shortening. In cisplatin-resistant human squamous cell cancer xenografts in nude mice, this combination therapy caused dramatic tumor regression with increased apoptosis. Our findings suggest the use of targeted RAD50 disruption as what we believe to be a novel chemosensitizing approach for cancer therapy in the context of chemoresistance. This strategy is potentially applicable to several types of malignant tumors that demonstrate chemoresistance and may positively impact the treatment of these patients.
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Affiliation(s)
- Waleed M. Abuzeid
- Department of Otorhinolaryngology — Head and Neck Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Otolaryngology — Head and Neck Surgery, and
Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Xiaoling Jiang
- Department of Otorhinolaryngology — Head and Neck Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Otolaryngology — Head and Neck Surgery, and
Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Guoli Shi
- Department of Otorhinolaryngology — Head and Neck Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Otolaryngology — Head and Neck Surgery, and
Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Hui Wang
- Department of Otorhinolaryngology — Head and Neck Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Otolaryngology — Head and Neck Surgery, and
Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - David Paulson
- Department of Otorhinolaryngology — Head and Neck Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Otolaryngology — Head and Neck Surgery, and
Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Koji Araki
- Department of Otorhinolaryngology — Head and Neck Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Otolaryngology — Head and Neck Surgery, and
Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - David Jungreis
- Department of Otorhinolaryngology — Head and Neck Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Otolaryngology — Head and Neck Surgery, and
Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - James Carney
- Department of Otorhinolaryngology — Head and Neck Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Otolaryngology — Head and Neck Surgery, and
Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Bert W. O’Malley
- Department of Otorhinolaryngology — Head and Neck Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Otolaryngology — Head and Neck Surgery, and
Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Daqing Li
- Department of Otorhinolaryngology — Head and Neck Surgery, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
Department of Otolaryngology — Head and Neck Surgery, and
Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Abstract
Double-strand breaks (DSBs) are deleterious DNA lesions and if left unrepaired result in severe genomic instability. Cells use two main pathways to repair DSBs: homologous recombination (HR) or non-homologous end joining (NHEJ) depending on the phase of the cell cycle and the nature of the DSB ends. A key step where pathway choice is exerted is in the 'licensing' of 5'-3' resection of the ends to produce recombinogenic 3' single-stranded tails. These tails are substrate for binding by Rad51 to initiate pairing and strand invasion with homologous duplex DNA. Moreover, the single-stranded DNA generated after end processing is important to activate the DNA damage response. The mechanism of end processing is the focus of this review and we will describe recent findings that shed light on this important initiating step for HR. The conserved MRX/MRN complex appears to be a major regulator of DNA end processing. Sae2/CtIP functions with the MRX complex, either to activate the Mre11 nuclease or via the intrinsic endonuclease, in an initial step to trim the DSB ends. In a second step, redundant systems remove long tracts of DNA to reveal extensive 3' single-stranded tails. One system is dependent on the helicase Sgs1 and the nuclease Dna2, and the other on the 5'-3' exonuclease Exo1.
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Affiliation(s)
- Eleni P Mimitou
- Department of Microbiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, United States
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30
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Meiotic localization of Mre11 and Rad50 in wild type, spo11-1, and MRN complex mutants of Coprinus cinereus. Chromosoma 2009; 118:471-86. [PMID: 19396455 DOI: 10.1007/s00412-009-0209-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 02/28/2009] [Accepted: 03/07/2009] [Indexed: 10/20/2022]
Abstract
The Mre11-Rad50-Nbs1 (MRN) complex is required for numerous cellular processes that involve interactions with DNA double-strand breaks. For the majority of these processes, the MRN complex is thought to act as a unit, with each protein aiding the activity of the others. We have examined the relationship between Mre11 and Rad50 during meiosis in the basidiomycete Coprinus cinereus (Coprinopsis cinerea), investigating to what extent activities of Mre11 and Rad50 are interdependent. We showed that mre11-1 is epistatic to rad50-1 with respect to the time of meiotic arrest, indicating that Mre11 activity facilitates the diffuse diplotene arrest of rad50 mutants. Anti-Mre11 and anti-Rad50 antibodies were used to examine MRN complex localization in a wild-type strain and in spo11, mre11, and rad50 mutants. In wild type, numbers of Mre11 and Rad50 foci peaked at time points corresponding to leptotene and early zygotene. In the spo11-1 mutant, which is defective in meiotic double-strand break formation, foci accumulated throughout prophase I. Of seven MRN mutants examined, only two rad50 strains exhibited Mre11 and Rad50 foci that localized to chromatin, although Mre11 protein was found in the cell for all of them. Analysis of predicted mutant structures showed that stable localization of Mre11 and Rad50 does not depend upon a wild-type hook-proximal coiled coil, but does require the presence of the Rad50 ATPase/adenylate cyclase domains. We found that Mre11 and Rad50 were interdependent for binding to meiotic chromosomes. However, the majority of foci observed apparently contained only one of the two proteins. Independent Mre11 and Rad50 foci might indicate disassociation of the complex during meiosis or could reflect independent structural roles for the two proteins in meiotic chromatin.
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31
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The MRX complex stabilizes the replisome independently of the S phase checkpoint during replication stress. EMBO J 2009; 28:1142-56. [PMID: 19279665 DOI: 10.1038/emboj.2009.60] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Accepted: 02/11/2009] [Indexed: 12/21/2022] Open
Abstract
The Mre11-Rad50-Xrs2 (MRX) complex has an important function in the maintenance of genomic integrity by contributing to the detection and repair of chromosome breaks. Here we show that the complex is recruited to sites of paused forks where it stabilizes the association of essential replisome components. Interestingly, this function is not dependent on the S phase checkpoint or the nuclease activity of Mre11. We find that disruption of the MRX complex leads to a loss of fork recovery and a failure to properly complete DNA replication when cells are exposed to replication stress. Our data suggest that one critical function of the MRX complex during replication is to promote the cohesion of sister chromatids at paused forks, offering an explanation for why MRX deficiency leads to a loss of cell viability and high levels of chromosome rearrangements under conditions of replication stress.
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32
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Abstract
Upon induction of DNA double-strand breaks (DSBs), Mre11 and Rad50 proteins of the Mre11 DNA repair complex accumulate at the sites of DSBs and form discrete nuclear foci. Precision in scoring of Mre11/Rad50-containing foci depends upon detection of those foci, some of which have a fluorescence staining intensity that is too close to the fluorescence staining intensity of the remaining Mre11 and Rad50 proteins that have not been incorporated into foci. Human U-1 melanoma cells in exponential growth were irradiated with various doses of X-rays (0-12 Gy) to induce the formation of repair foci. Four hours after irradiation, cells were simultaneously labeled for Mre11 and Rad50 proteins, using a two-color immunofluorescence staining technique. Laser scanning confocal microscopy was used to collect the composite images of randomly selected cell nuclei. Intensity correlation analysis (ICA) of equally intense fluorescence signals from Mre11 and Rad50 proteins was performed to obtain the regions with correlated pixels. ICA permitted enhanced detection of low level fluorescence of Mre11/Rad50 foci ("hidden" foci) that can be barely detected upon imaging of only one protein. For example, while imaging of only one protein (either Mre11 or Rad50) in the nucleus of a 6 Gy-irradiated cell revealed 9 foci, imaging of two proteins with ICA revealed 11 foci. ICA permitted an evaluation of the dose dependence of nuclear foci in cells irradiated with various doses of X-rays, with focus formation increasing up to a dose of 6 Gy. Our data accumulated using two-color immunofluorescence staining of Mre11 and Rad50 proteins and ICA of these two target proteins provide a basis for enhanced detection and accuracy in the scoring of DNA repair foci.
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Affiliation(s)
- Bogdan I. Gerashchenko
- Departments of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Joseph R. Dynlacht
- Departments of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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33
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De Boeck G, Forsyth RG, Praet M, Hogendoorn PCW. Telomere-associated proteins: cross-talk between telomere maintenance and telomere-lengthening mechanisms. J Pathol 2009; 217:327-44. [PMID: 19142887 DOI: 10.1002/path.2500] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Telomeres, the ends of eukaryotic chromosomes, have been the subject of intense investigation over the last decade. As telomere dysfunction has been associated with ageing and developing cancer, understanding the exact mechanisms regulating telomere structure and function is essential for the prevention and treatment of human cancers and age-related diseases. The mechanisms by which cells maintain telomere lengthening involve either telomerase or the alternative lengthening of the telomere pathway, although specific mechanisms of the latter and the relationship between the two are as yet unknown. Many cellular factors directly (TRF1/TRF2) and indirectly (shelterin-complex, PinX, Apollo and tankyrase) interact with telomeres, and their interplay influences telomere structure and function. One challenge comes from the observation that many DNA damage response proteins are stably associated with telomeres and contribute to several other aspects of telomere function. This review focuses on the different components involved in telomere maintenance and their role in telomere length homeostasis. Special attention is paid to understanding how these telomere-associated factors, and mainly those involved in double-strand break repair, perform their activities at the telomere ends.
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Affiliation(s)
- Gitte De Boeck
- N. Goormaghtigh Institute of Pathology, University Hospital Ghent, De Pintelaan 185, 9000 Ghent, Belgium
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34
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Coprinus cinereus rad50 mutants reveal an essential structural role for Rad50 in axial element and synaptonemal complex formation, homolog pairing and meiotic recombination. Genetics 2008; 180:1889-907. [PMID: 18940790 DOI: 10.1534/genetics.108.092775] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Mre11/Rad50/Nbs1 (MRN) complex is required for eukaryotic DNA double-strand break (DSB) repair and meiotic recombination. We cloned the Coprinus cinereus rad50 gene and showed that it corresponds to the complementation group previously named rad12, identified mutations in 15 rad50 alleles, and mapped two of the mutations onto molecular models of Rad50 structure. We found that C. cinereus rad50 and mre11 mutants arrest in meiosis and that this arrest is Spo11 dependent. In addition, some rad50 alleles form inducible, Spo11-dependent Rad51 foci and therefore must be forming meiotic DSBs. Thus, we think it likely that arrest in both mre11-1 and the collection of rad50 mutants is the result of unrepaired or improperly processed DSBs in the genome and that Rad50 and Mre11 are dispensable in C. cinereus for DSB formation, but required for appropriate DSB processing. We found that the ability of rad50 mutant strains to form Rad51 foci correlates with their ability to promote synaptonemal complex formation and with levels of stable meiotic pairing and that partial pairing, recombination initiation, and synapsis occur in the absence of wild-type Rad50 catalytic domains. Examination of single- and double-mutant strains showed that a spo11 mutation that prevents DSB formation enhances axial element (AE) formation for rad50-4, an allele predicted to encode a protein with intact hook region and hook-proximal coiled coils, but not for rad50-1, an allele predicted to encode a severely truncated protein, or for rad50-5, which encodes a protein whose hook-proximal coiled-coil region is disrupted. Therefore, Rad50 has an essential structural role in the formation of AEs, separate from the DSB-processing activity of the MRN complex.
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35
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Mathew SS, Bridge E. Nbs1-dependent binding of Mre11 to adenovirus E4 mutant viral DNA is important for inhibiting DNA replication. Virology 2008; 374:11-22. [PMID: 18234271 DOI: 10.1016/j.virol.2007.12.034] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Revised: 08/30/2007] [Accepted: 12/14/2007] [Indexed: 11/24/2022]
Abstract
Adenovirus (Ad) infections stimulate the activation of cellular DNA damage response and repair pathways. Ad early regulatory proteins prevent activation of DNA damage responses by targeting the MRN complex, composed of the Mre11, Rad50 and Nbs1 proteins, for relocalization and degradation. In the absence of these viral proteins, Mre11 colocalizes with viral DNA replication foci. Mre11 foci formation at DNA damage induced by ionizing radiation depends on the Nbs1 component of the MRN complex and is stabilized by the mediator of DNA damage checkpoint protein 1 (Mdc1). We find that Nbs1 is required for Mre11 localization at DNA replication foci in Ad E4 mutant infections. Mre11 is important for Mdc1 foci formation in infected cells, consistent with its role as a sensor of DNA damage. Chromatin immunoprecipitation assays indicate that both Mre11 and Mdc1 are physically bound to viral DNA, which could account for their localization in viral DNA containing foci. Efficient binding of Mre11 to E4 mutant DNA depends on the presence of Nbs1, and is correlated with a significant E4 mutant DNA replication defect. Our results are consistent with a model in which physical interaction of Mre11 with viral DNA is mediated by Nbs1, and interferes with viral DNA replication.
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Affiliation(s)
- Shomita S Mathew
- Department of Microbiology, 32 Pearson Hall, Miami University, Oxford, OH 45056, USA
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36
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Czornak K, Chughtai S, Chrzanowska KH. Mystery of DNA repair: the role of the MRN complex and ATM kinase in DNA damage repair. J Appl Genet 2008; 49:383-96. [PMID: 19029686 DOI: 10.1007/bf03195638] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Genomes are subject to a number of exogenous or endogenous DNA-damaging agents that cause DNA double-strand breaks (DSBs). These critical DNA lesions can result in cell death or a wide variety of genetic alterations, including deletions, translocations, loss of heterozygosity, chromosome loss, or chromosome fusions, which enhance genome instability and can trigger carcinogenesis. The cells have developed an efficient mechanism to cope with DNA damages by evolving the DNA repair machinery. There are 2 major DSB repair mechanisms: nonhomologous end joining (NHEJ) and homologous recombination (HR). One element of the repair machinery is the MRN complex, consisting of MRE11, RAD50 and NBN (previously described as NBS1), which is involved in DNA replication, DNA repair, and signaling to the cell cycle checkpoints. A number of kinases, like ATM (ataxia-telangiectasia mutated), ATR (ataxia-telangiectasia and Rad-3-related), and DNA PKcs (DNA protein kinase catalytic subunit), phosphorylate various protein targets in order to repair the damage. If the damage cannot be repaired, they direct the cell to apoptosis. The MRN complex as well as repair kinases are also involved in telomere maintenance and genome stability. The dysfunction of particular elements involved in the repair mechanisms leads to genome instability disorders, like ataxia telangiectasia (A-T), A-T-like disorder (ATLD) and Nijmegen breakage syndrome (NBS). The mutated genes responsible for these disorders code for proteins that play key roles in the process of DNA repair. Here we present a detailed review of current knowledge on the MRN complex, kinases engaged in DNA repair, and genome instability disorders.
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Affiliation(s)
- Kamila Czornak
- Children's Memorial Health Institute, Department of Medical Genetics, Warsaw, Poland
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37
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Donahue SL, Tabah AA, Schmitz K, Aaron A, Campbell C. Defective signal joint recombination in fanconi anemia fibroblasts reveals a role for Rad50 in V(D)J recombination. J Mol Biol 2007; 370:449-58. [PMID: 17524422 PMCID: PMC2727996 DOI: 10.1016/j.jmb.2007.03.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 03/02/2007] [Accepted: 03/05/2007] [Indexed: 10/23/2022]
Abstract
V(D)J recombination of immunoglobulin loci is dependent on the immune cell-specific Rag1 and Rag2 proteins as well as a number of ubiquitously expressed cellular DNA repair proteins that catalyze non-homologous end-joining of DNA double-strand breaks. The evolutionarily conserved Rad50/Mre11/Nibrin protein complex has a role in DNA double-strand break-repair, suggesting that these proteins, too, may participate in V(D)J recombination. Recent findings demonstrating that Rad50 function is defective in cells from patients afflicted with Fanconi anemia provide a possible mechanistic explanation for previous findings that lymphoblasts derived from these patients exhibit subtle defects in V(D)J recombination of extrachromosomal plasmid molecules. Here, we describe a series of findings that provide convincing evidence for a role of the Rad50 protein complex in V(D)J recombination. We found that the fidelity of V(D)J signal joint recombination in fibroblasts from patients afflicted with Fanconi anemia was reduced by nearly tenfold, compared to that observed in fibroblasts from normal donors. Second, we observed that antibody-mediated inhibition of the Rad50, Mre11, or Nibrin proteins reduced the fidelity of signal joint recombination significantly in wild-type cells. The latter finding was somewhat unexpected, because signal joint rejoining in cells from patients with Nijmegen breakage syndrome, which results from mutations in the Nibrin gene, occurs with normal fidelity. However, introduction of anti-Nibrin antibodies into these cells reduced the fidelity of signal joint recombination dramatically. These data reveal for the first time a role for the Rad50 complex in V(D)J recombination, and demonstrate that the protein product of the disease-causing allele responsible for Nijmegen breakage syndrome encodes a protein with residual DNA double-strand break repair activity.
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Affiliation(s)
| | | | - Kyle Schmitz
- From the Department of Pharmacology, University of Minnesota Medical School, 6-120 Jackson Hall, 321 Church Street SE, Minneapolis MN 55455
| | - Ashley Aaron
- From the Department of Pharmacology, University of Minnesota Medical School, 6-120 Jackson Hall, 321 Church Street SE, Minneapolis MN 55455
| | - Colin Campbell
- From the Department of Pharmacology, University of Minnesota Medical School, 6-120 Jackson Hall, 321 Church Street SE, Minneapolis MN 55455
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38
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Heikkinen K, Rapakko K, Karppinen SM, Erkko H, Knuutila S, Lundán T, Mannermaa A, Børresen-Dale AL, Borg Å, Barkardottir RB, Petrini J, Winqvist R. RAD50 and NBS1 are breast cancer susceptibility genes associated with genomic instability. Carcinogenesis 2006; 27:1593-9. [PMID: 16474176 PMCID: PMC3006189 DOI: 10.1093/carcin/bgi360] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The Mre11 complex, composed of RAD50, NBS1 and MRE11, has an essential role in the maintenance of genomic integrity and preventing cells from malignancy. Here we report the association of three Mre11 complex mutations with hereditary breast cancer susceptibility, studied by using a case-control design with 317 consecutive, newly diagnosed Northern Finnish breast cancer patients and 1000 geographically matched healthy controls (P = 0.0004). RAD50 687delT displayed significantly elevated frequency in the studied patients (8 out of 317, OR 4.3, 95% CI 1.5-12.5, P= 0.008), which indicates that it is a relatively common low-penetrance risk allele in this cohort. Haplotype analysis and the screening of altogether 512 additional breast cancer cases from Sweden, Norway and Iceland suggest that RAD50 687delT is a Finnish founder mutation, not present in the other Nordic cohorts. The RAD50 IVS3-1G>A splicing mutation leading to translational frameshift was observed in one patient, and the NBS1 Leu150Phe missense mutation affecting a conserved residue in the functionally important BRCA1 carboxy-terminal (BRCT) domain in two patients, both being absent from 1000 controls. Microsatellite marker analysis showed that loss of the wild-type allele was not involved in the tumorigenesis in any of the studied mutation carriers, but they all showed increased genomic instability assessed by cytogenetic analysis of peripheral blood T-lymphocytes (P = 0.006). In particular, the total number of chromosomal rearrangements was significantly increased (P = 0.002). These findings suggest an effect for RAD50 and NBS1 haploinsufficiency on genomic integrity and susceptibility to cancer.
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Affiliation(s)
- Katri Heikkinen
- Department of Clinical Genetics, University of Oulu/Oulu University Hospital, Oulu, Finland
| | - Katrin Rapakko
- Department of Clinical Genetics, University of Oulu/Oulu University Hospital, Oulu, Finland
| | - Sanna-Maria Karppinen
- Department of Clinical Genetics, University of Oulu/Oulu University Hospital, Oulu, Finland
| | - Hannele Erkko
- Department of Clinical Genetics, University of Oulu/Oulu University Hospital, Oulu, Finland
| | - Sakari Knuutila
- Department of Pathology, Haartman Institute, University of Helsinki and HUSLAB Helsinki University Central Hospital, Finland
| | - Tuija Lundán
- Department of Clinical Genetics, University of Oulu/Oulu University Hospital, Oulu, Finland
- Department of Pathology, Haartman Institute, University of Helsinki and HUSLAB Helsinki University Central Hospital, Finland
| | - Arto Mannermaa
- Department of Clinical Genetics, University of Oulu/Oulu University Hospital, Oulu, Finland
| | | | - Åke Borg
- Department of Oncology, Lund University Hospital, Lund, Sweden
| | | | - John Petrini
- Department of Molecular Biology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Robert Winqvist
- Department of Clinical Genetics, University of Oulu/Oulu University Hospital, Oulu, Finland
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39
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Trenz K, Smith E, Smith S, Costanzo V. ATM and ATR promote Mre11 dependent restart of collapsed replication forks and prevent accumulation of DNA breaks. EMBO J 2006; 25:1764-74. [PMID: 16601701 PMCID: PMC1440833 DOI: 10.1038/sj.emboj.7601045] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2005] [Accepted: 02/22/2006] [Indexed: 01/14/2023] Open
Abstract
Ataxia-telangiectasia mutated (ATM), ataxia-telangiectasia Rad3-related (ATR) and the Mre11/Rad50/Nbs1 complex ensure genome stability in response to DNA damage. However, their essential role in DNA metabolism remains unknown. Here we show that ATM and ATR prevent accumulation of DNA double-strand breaks (DSBs) during chromosomal replication. Replicating chromosomes accumulate DSBs in Xenopus laevis egg extracts depleted of ATM and ATR. Addition of ATM and ATR proteins to depleted extracts prevents DSB accumulation by promoting restart of collapsed replication forks that arise during DNA replication. We show that collapsed forks maintain MCM complex but lose Pol epsilon, and that Pol epsilon reloading requires ATM and ATR. Replication fork restart is abolished in Mre11 depleted extracts and is restored by supplementation with recombinant human Mre11/Rad50/Nbs1 complex. Using a novel fluorescence resonance energy transfer-based technique, we demonstrate that ATM and ATR induce Mre11/Rad50/Nbs1 complex redistribution to restarting forks. This study provides direct biochemical evidence that ATM and ATR prevent accumulation of chromosomal abnormalities by promoting Mre11/Rad50/Nbs1 dependent recovery of collapsed replication forks.
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Affiliation(s)
- Kristina Trenz
- Genome Stability Unit, London Research Institute, Clare Hall Laboratories, South Mimms, London, UK
| | - Eloise Smith
- Genome Stability Unit, London Research Institute, Clare Hall Laboratories, South Mimms, London, UK
| | - Sarah Smith
- Genome Stability Unit, London Research Institute, Clare Hall Laboratories, South Mimms, London, UK
| | - Vincenzo Costanzo
- Genome Stability Unit, London Research Institute, Clare Hall Laboratories, South Mimms, London, UK
- Genome Stability Unit, London Research Institute, Clare Hall Laboratories, Blanch Lane, South Mimms, EN6 3LD London, UK. Tel.: +44 1707 625548; Fax: +44 1707 625546; E-mail:
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40
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Zhou J, Lim CUK, Li JJ, Cai L, Zhang Y. The role of NBS1 in the modulation of PIKK family proteins ATM and ATR in the cellular response to DNA damage. Cancer Lett 2006; 243:9-15. [PMID: 16530324 PMCID: PMC3658610 DOI: 10.1016/j.canlet.2006.01.026] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Revised: 01/23/2006] [Accepted: 01/24/2006] [Indexed: 01/10/2023]
Abstract
Ataxia telangiectasia mutated (ATM) and ataxia telangiectasia and Rad3-related (ATR) kinases have been considered the primary activators of the cellular response to DNA damage. They belong to the protein kinase family, phosphoinositide 3-kinase-related kinase (PIKKs). In human beings, deficiency of these kinases leads to hereditary diseases, namely ataxia telangiectasia (AT) with ATM deficiency and ATR-Seckel with ATR deficiency. NBS1, a component of MRE11/RAD50/NBS1 (MRN) complex, is another important player in DNA damage response (DDR). Mutations of NBS1 are responsible for Nijmegen breakage syndrome (NBS), a human hereditary disease with the characteristics that almost encompassed those of AT and ATR-Seckel. NBS1 has been conventionally thought to be a downstream substrate of ATM and ATR in DDR; however, recent studies suggest that NBS1/MRN functions upstream of both ATM and ATR by recruiting them to the proximity of DNA damage sites and activating their functions. In this mini-review, we would emphasize the requirement of NBS1 as an upstream mediator for the modulation of PIKK family proteins ATM and ATR.
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Affiliation(s)
- Junqing Zhou
- Department of Environmental and Radiological Health Science, Colorado State University, Fort Collins, CO 80521, USA
| | - Chang UK Lim
- Cancer Center, Ordway Research Institute, 150 New Scotland Avenue Rm 4133, Albany, NY 12208, USA
| | - Jian Jian Li
- Division of Molecular Radiobiology, Purdue University School of Health Sciences, West Lafayette, IN 47907, USA
| | - Lu Cai
- Department of Medicine and Radiation Oncology, University of Louisville, School of Medicine, Louisville, KT 40202, USA
- Corresponding authors. Tel.: +1 970 491 0574; fax: +1 970 491 0623. (Y. Zhang). * Tel.: +1 502 852 5215; fax: +1 502 852 6904 (L. Cai). (Y. Zhang), (L. Cai)
| | - Ying Zhang
- Department of Environmental and Radiological Health Science, Colorado State University, Fort Collins, CO 80521, USA
- Corresponding authors. Tel.: +1 970 491 0574; fax: +1 970 491 0623. (Y. Zhang). * Tel.: +1 502 852 5215; fax: +1 502 852 6904 (L. Cai). (Y. Zhang), (L. Cai)
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41
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Cerosaletti K, Wright J, Concannon P. Active role for nibrin in the kinetics of atm activation. Mol Cell Biol 2006; 26:1691-9. [PMID: 16478990 PMCID: PMC1430256 DOI: 10.1128/mcb.26.5.1691-1699.2006] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2005] [Revised: 09/27/2005] [Accepted: 12/06/2005] [Indexed: 01/02/2023] Open
Abstract
The Atm protein kinase is central to the DNA double-strand break response in mammalian cells. After irradiation, dimeric Atm undergoes autophosphorylation at Ser 1981 and dissociates into active monomers. Atm activation is stimulated by expression of the Mre11/Rad50/nibrin complex. Previously, we showed that a C-terminal fragment of nibrin, containing binding sites for both Mre11 and Atm, was sufficient to provide this stimulatory effect in Nijmegen breakage syndrome (NBS) cells. To discriminate whether nibrin's role in Atm activation is to bind and translocate Mre11/Rad50 to the nucleus or to interact directly with Atm, we expressed an Mre11 transgene with a C-terminal NLS sequence in NBS fibroblasts. The Mre11-NLS protein complexed with Rad50, localized to the nucleus in NBS fibroblasts, and associated with chromatin. However, Atm autophosphorylation was not stimulated in cells expressing Mre11-NLS, nor were downstream Atm targets phosphorylated. To determine whether nibrin-Atm interaction is necessary to stimulate Atm activation, we expressed nibrin transgenes lacking the Atm binding domain in NBS fibroblasts. The nibrin DeltaAtm protein interacted with Mre11/Rad50; however, Atm autophosphorylation was dramatically reduced after irradiation in NBS cells expressing the nibrin DeltaAtm transgenes relative to wild-type nibrin. These results indicate that nibrin plays an active role in Atm activation beyond translocating Mre11/Rad50 to the nucleus and that this function requires nibrin-Atm interaction.
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Affiliation(s)
- Karen Cerosaletti
- Molecular Genetics Program, Benaroya Research Institute, Seattle, WA 98101, USA
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Chuang YK, Cheng WC, Goodman SD, Chang YT, Kao JT, Lee CN, Tsai KS, Fang WH. Nick-directed repair of palindromic loop mismatches in human cell extracts. J Biomed Sci 2005; 12:659-69. [PMID: 16078003 DOI: 10.1007/s11373-005-7891-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Accepted: 05/25/2005] [Indexed: 11/28/2022] Open
Abstract
Palindromic sequences present in DNA may form secondary structures that block DNA replication and transcription causing adverse effects on genome stability. It has been suggested that hairpin structures containing mispaired bases could stimulate the repair systems in human cells. In this study, processing of variable length of palindromic loops in the presence or absence of single-base mismatches was investigated in human cell extracts. Our results showed that hairpin structures were efficiently processed through a nick-directed mechanism. In a similar sequence context, mismatch-containing hairpins have higher repair efficiencies. We also found that shorter hairpins are generally better repaired. A strand break located either 3' or 5' to the loop is sufficient to activate hairpin repair on the nicked strand. The reaction requires Mg(2+), the four dNTPs and hydrolysis of ATP for efficient repair on both palindromic loop insertions and deletions. Correction of each of these heteroduplexes was abolished by aphidicolin but was relatively insensitive to the presence of ddTTP, suggesting involvement of polymerase(s) alpha and/or delta. These findings are most consistent with the nick-directed loop repair pathway being responsible for processing hairpin heterologies in human cells.
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Affiliation(s)
- Yi-Kuang Chuang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, 7, Chung-Shan South Road, 100-63, Taipei, Taiwan, ROC
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Bleuyard JY, Gallego ME, White CI. Recent advances in understanding of the DNA double-strand break repair machinery of plants. DNA Repair (Amst) 2005; 5:1-12. [PMID: 16202663 DOI: 10.1016/j.dnarep.2005.08.017] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2005] [Revised: 08/22/2005] [Accepted: 08/22/2005] [Indexed: 11/21/2022]
Abstract
Living cells suffer numerous and varied alterations of their genetic material. Of these, the DNA double-strand break (DSB) is both particularly threatening and common. Double-strand breaks arise from exposure to DNA damaging agents, but also from cell metabolism-in a fortuitous manner during DNA replication or repair of other kinds of lesions and in a programmed manner, for example during meiosis or V(D)J gene rearrangement. Cells possess several overlapping repair pathways to deal with these breaks, generally designated as genetic recombination. Genetic and biochemical studies have provided considerable amounts of data about the proteins involved in recombination processes and their functions within these processes. Although they have long played a key role in building understanding of genetics, relatively little is known at the molecular level of the genetic recombination processes in plants. The use of reverse genetic approaches and the public availability of sequence tagged mutants in Arabidopsis thaliana have led to increasingly rapid progress in this field over recent years. The rapid progress of studies of recombination in plants is obviously not limited to the DSB repair machinery as such and we ask readers to understand that in order to maintain the focus and to rest within a reasonable length, we present only limited discussion of the exciting advances in the of plant meiosis field, which require a full review in their own right . We thus present here an update on recent advances in understanding of the DSB repair machinery of plants, focussing on Arabidopsis and making a particular effort to place these in the context of more general of understanding of these processes.
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Affiliation(s)
- Jean-Yves Bleuyard
- Cancer Research UK, London Research Institute, Clare Hall Laboratories, South Mimms, Herts EN6 3LD, UK.
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Kim ST. Protein kinase CK2 interacts with Chk2 and phosphorylates Mre11 on serine 649. Biochem Biophys Res Commun 2005; 331:247-52. [PMID: 15845385 DOI: 10.1016/j.bbrc.2005.03.162] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Indexed: 11/15/2022]
Abstract
The Mre11-Rad50-Nbs1 protein complex has been known to be involved in a variety of DNA metabolic events that involve DNA double-strand breaks (DSBs). The phosphorylation of Mre11 is increased in response to ionizing radiation, which suggests that phosphorylation of Mre11 may be an important regulatory mechanism of this complex. Mre11-phosphorylating kinase activities were observed in Chk2 immunoprecipitates and HeLa nuclear extracts. Through the tandem affinity tagging system and conventional chromatography, this kinase was purified and identified as protein kinase CK2. CK2 phosphorylates Mre11 in vitro. In vitro kinase assay with a series of truncated Mre11 proteins as substrates for CK2 and site-directed mutagenesis showed that serine 649 of Mre11 is mainly phosphorylated by CK2 in vitro. In vivo labeling and phosphopeptide mapping analysis revealed that this phosphorylation occurs in vivo. These data implicate CK2 as a potential upstream regulator of Mre11 function.
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Affiliation(s)
- Seong-Tae Kim
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, 300 Chunchundong, Jangangu, Suwon, Kyonggido 440-746, Republic of Korea.
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Alt JR, Bouska A, Fernandez MR, Cerny RL, Xiao H, Eischen CM. Mdm2 binds to Nbs1 at sites of DNA damage and regulates double strand break repair. J Biol Chem 2005; 280:18771-81. [PMID: 15734743 DOI: 10.1074/jbc.m413387200] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Mdm2 directly regulates the p53 tumor suppressor. However, Mdm2 also has p53-independent activities, and the pathways that mediate these functions are unresolved. Here we report the identification of a specific association of Mdm2 with Mre11, Nbs1, and Rad50, a DNA double strand break repair complex. Mdm2 bound to the Mre11-Nbs1-Rad50 complex in primary cells and in cells containing inactivated p53 or p14/p19ARF, a regulator of Mdm2. Further analysis revealed that Mdm2 directly bound to Nbs1 but not to Mre11 or Rad50. Amino acids 198-314 of Mdm2 were required for Mdm2/Nbs1 association, and neither the N terminus forkhead-associated and breast cancer C-terminal domains nor the C terminus Mre11 binding domain of Nbs1 mediated the interaction of Nbs1 with Mdm2. Mdm2 co-localized with Nbs1 to sites of DNA damage following gamma-irradiation. Notably, Mdm2 overexpression inhibited DNA double strand break repair, and this was independent of p53 and ARF, the alternative reading frame of the Ink4alocus. The delay in DNA repair imposed by Mdm2 required the Nbs1 binding domain of Mdm2, but the ubiquitin ligase domain in Mdm2 was dispensable. Therefore, Nbs1 is a novel p53-independent Mdm2 binding protein and links Mdm2 to the Mre11-Nbs1-Rad50-regulated DNA repair response.
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Affiliation(s)
- Jodi R Alt
- Eppley Institute for Research in Cancer and Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha 68198, USA
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Dudásová Z, Dudás A, Chovanec M. Non-homologous end-joining factors of Saccharomyces cerevisiae. FEMS Microbiol Rev 2005; 28:581-601. [PMID: 15539075 DOI: 10.1016/j.femsre.2004.06.001] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2004] [Revised: 06/02/2004] [Accepted: 06/02/2004] [Indexed: 01/09/2023] Open
Abstract
DNA double-strand breaks (DSB) are considered to be a severe form of DNA damage, because if left unrepaired, they can cause a cell death and, if misrepaired, they can lead to genomic instability and, ultimately, the development of cancer in multicellular organisms. The budding yeast Saccharomyces cerevisiae repairs DSB primarily by homologous recombination (HR), despite the presence of the KU70, KU80, DNA ligase IV and XRCC4 homologues, essential factors of the mammalian non-homologous end-joining (NHEJ) machinery. S. cerevisiae, however, lacks clear DNA-PKcs and ARTEMIS homologues, two important additional components of mammalian NHEJ. On the other hand, S. cerevisiae is endowed with a regulatory NHEJ component, Nej1, which has not yet been found in other organisms. Furthermore, there is evidence in budding yeast for a requirement for the Mre11/Rad50/Xrs2 complex for NHEJ, which does not appear to be the case either in Schizosaccharomyces pombe or in mammals. Here, we comprehensively describe the functions of all the S. cerevisiae NHEJ components identified so far and present current knowledge about the NHEJ process in this organism. In addition, this review depicts S. cerevisiae as a powerful model system for investigating the utilization of either NHEJ or HR in DSB repair.
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Affiliation(s)
- Zuzana Dudásová
- Laboratory of Molecular Genetics, Cancer Research Institute, Slovak Academy of Sciences, Vlárska 7, 833 91 Bratislava 37, Slovak Republic
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Gorski MM, Romeijn RJ, Eeken JCJ, de Jong AWM, van Veen BL, Szuhai K, Mullenders LH, Ferro W, Pastink A. Disruption of Drosophila Rad50 causes pupal lethality, the accumulation of DNA double-strand breaks and the induction of apoptosis in third instar larvae. DNA Repair (Amst) 2004; 3:603-15. [PMID: 15135728 DOI: 10.1016/j.dnarep.2004.02.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2003] [Revised: 02/04/2004] [Accepted: 02/09/2004] [Indexed: 01/17/2023]
Abstract
The Rad50/Mre11/Nbs1 protein complex has a crucial role in DNA metabolism, in particular in double-strand break (DSB) repair through homologous recombination (HR). To elucidate the role of the Rad50 protein complex in DSB repair in a multicellular eukaryote, we generated a Rad50 deficient Drosophila strain by P-element mediated mutagenesis. Disruption of Rad50 causes retarded development and pupal lethality. To investigate the mechanism of pupal death, brains and wing imaginal discs from third instar larvae were studied in more detail. Wing imaginal discs from Rad50 mutant larvae displayed a 3.5-fold increase in the induction of spontaneous apoptotic cells in comparison to their heterozygous siblings. This finding correlates with increased levels of phosphorylated histone H2Av, indicating an accumulation of DSBs in Rad50 mutant larvae. A 45-fold increase in the frequency of anaphase bridges was detected in the brains of Rad50 deficient larvae, consistent with a role for Rad50 in telomere maintenance and/or replication of DNA. The induction of DSBs and defects in chromosome segregation are in agreement with a role of Drosophila Rad50 in repairing the DSBs that arise during replication.
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Affiliation(s)
- Marcin M Gorski
- Department of Toxicogenetics, Leiden University Medical Center, Wassenaarseweg 72, 2333 AL Leiden, The Netherlands
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Llorente B, Symington LS. The Mre11 nuclease is not required for 5' to 3' resection at multiple HO-induced double-strand breaks. Mol Cell Biol 2004; 24:9682-94. [PMID: 15485933 PMCID: PMC522228 DOI: 10.1128/mcb.24.21.9682-9694.2004] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Current hypotheses suggest the Mre11 nuclease activity could be directly involved in double-strand break (DSB) resection in the presence of a large number of DSBs or limited to processing abnormal DNA ends. To distinguish between these possibilities, we used two methods to create large numbers of DSBs in Saccharomyces cerevisiae chromosomes, without introducing other substrates for the Mre11 nuclease. Multiple DSBs were created either by expressing the HO endonuclease in strains containing several HO cut sites embedded within randomly dispersed Ty1 elements or by phleomycin treatment. Analysis of resection by single-strand DNA formation in these systems showed no difference between strains containing MRE11 or the mre11-D56N nuclease defective allele, suggesting that the Mre11 nuclease is not involved in the extensive 5' to 3' resection of DSBs. We postulate that the ionizing radiation (IR) sensitivity of mre11 nuclease-defective mutants results from the accumulation of IR-induced DNA damage that is normally processed by the Mre11 nuclease. We also report that the processivity of 5' to 3' DSB resection and the yield of repaired products are affected by the number of DSBs in a dose-dependent manner. Finally, we show that the exonuclease Exo1 is involved in the processivity of 5' to 3' resection of an HO-induced DSB at the MAT locus.
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Affiliation(s)
- Bertrand Llorente
- Department of Microbiology, Columbia University Medical Center, 701 W. 168th St., New York, NY 10032, USA
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Iwanaga R, Komori H, Ohtani K. Differential regulation of expression of the mammalian DNA repair genes by growth stimulation. Oncogene 2004; 23:8581-90. [PMID: 15467751 DOI: 10.1038/sj.onc.1207976] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2004] [Revised: 06/09/2004] [Accepted: 06/16/2004] [Indexed: 01/17/2023]
Abstract
During DNA replication, DNA becomes more vulnerable to certain DNA damages. DNA repair genes involved in repair of the damages may be induced by growth stimulation. However, regulation of DNA repair genes by growth stimulation has not been analysed in detail. In this report, we analysed the regulation of expression of mammalian MSH2, MSH3 and MLH1 genes involved in mismatch repair, and Rad51 and Rad50 genes involved in homologous recombination repair, in relation to cell growth. Unexpectedly, we found a clear difference in regulation of these repair gene expression by growth stimulation even in the same repair system. The expression of MSH2, MLH1 and Rad51 genes was clearly growth regulated, whereas MSH3 and Rad50 genes were constitutively expressed, suggesting differential requirement of the repair gene products for cell proliferation. MSH3 gene is located in a bidirectionally divergent manner with DHFR gene that is regulated by growth stimulation, indicating that bidirectionally divergent promoters are not necessarily coordinately regulated. Promoter analysis showed that the growth-regulated expression of MLH1 and Rad51 genes was mainly mediated by E2F that plays crucial roles in regulation of DNA replication, suggesting close relation between some of the repair genes and DNA replication.
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Affiliation(s)
- Ritsuko Iwanaga
- Human Gene Sciences Center, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
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Tran HM, Shi G, Li G, Carney JP, O'Malley B, Li D. Mutant Nbs1 enhances cisplatin-induced DNA damage and cytotoxicity in head and neck cancer. Otolaryngol Head Neck Surg 2004; 131:477-84. [PMID: 15467621 DOI: 10.1016/j.otohns.2004.04.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Enhanced DNA double-strand break (DSB) repair could be a primary cause for development of resistance in tumor cells to cisplatin, which induces crosslinks and DNA DSBs. A protein complex consisting of hMre11, hRad50, and Nbs1 (MRN) has been identified as a critical component in repair of DNA DSBs. The present study investigates whether the expression of a truncated form of Nbs1 interrupts the function of the MRN complex and therefore enhances cisplatin-induced DNA damage and cytotoxicity in human head and neck squamous cell carcinoma (HNSCC). METHODS AND MEASURES Two human HNSCC cell lines, JHU006 and JHU029, were used. A dominant negative recombinant adenovirus expressing domains of Nbs1 was constructed. Adenovirus-mediated mutant Nbs1 (Ad-Nbs1) gene transfer was performed with replication-defective virus (DL312) and no treatment as controls. Transgene expression and cell viability were evaluated in transfected cells. Neutral comet assay was performed and the "tail moment," the product of the amount of DNA in the tail and the distance of tail migration, was analyzed for evaluating DNA DSB damage at 24, 48, and 72 hours. RESULTS Transgene expression of mutant Nbs1 was confirmed by Western blotting. Ad-Nbs1 gene transfer significantly increased cisplatin-induced cytotoxicity as shown by stunting of 6-day growth curves. Neutral comet analysis revealed that the mean tail moment, indicative of DNA damage, was significantly elevated in cells treated with combined cisplatin and Ad-Nbs1 compared to cisplatin alone in both cell lines. CONCLUSIONS Expression of mutant Nbs1 significantly increases cisplatin-induced DNA DSBs and cytotoxicity. The increase in double-strand DNA damage corresponds to the level of cytotoxicity in the different treatment groups and suggests that tumor chemosensitization occurs through augmentation of DNA DSBs. CLINICAL SIGNIFICANCE Alteration of DNA repair may provide a novel approach to enhancing sensitivity of HNSCC to chemotherapy. Our study supports the potential application of Ad-Nbs1 in combination with cisplatin for treatment of advanced and metastatic HNSCC.
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Affiliation(s)
- Hao Mimi Tran
- Department of Otolarygology-Head and Neck Surgery, University of Maryland School of Medicine, Baltimore, USA
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