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Schreuder A, Wendel TJ, Dorresteijn CGV, Noordermeer SM. (Single-stranded DNA) gaps in understanding BRCAness. Trends Genet 2024; 40:757-771. [PMID: 38789375 DOI: 10.1016/j.tig.2024.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/26/2024]
Abstract
The tumour-suppressive roles of BRCA1 and 2 have been attributed to three seemingly distinct functions - homologous recombination, replication fork protection, and single-stranded (ss)DNA gap suppression - and their relative importance is under debate. In this review, we examine the origin and resolution of ssDNA gaps and discuss the recent advances in understanding the role of BRCA1/2 in gap suppression. There are ample data showing that gap accumulation in BRCA1/2-deficient cells is linked to genomic instability and chemosensitivity. However, it remains unclear whether there is a causative role and the function of BRCA1/2 in gap suppression cannot unambiguously be dissected from their other functions. We therefore conclude that the three functions of BRCA1 and 2 are closely intertwined and not mutually exclusive.
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Affiliation(s)
- Anne Schreuder
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands
| | - Tiemen J Wendel
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands
| | - Carlo G V Dorresteijn
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands
| | - Sylvie M Noordermeer
- Leiden University Medical Center, Department of Human Genetics, Leiden, The Netherlands; Oncode Institute, Utrecht, The Netherlands.
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2
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Chang J, Liu A, Zhang J, Chu L, Hou X, Huang X, Xing Q, Bao Z. Transcriptomic analysis reveals PC4's participation in thermotolerance of scallop Argopecten irradians irradians by regulating myocardial bioelectric activity. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2024; 52:101295. [PMID: 39053238 DOI: 10.1016/j.cbd.2024.101295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 07/02/2024] [Accepted: 07/17/2024] [Indexed: 07/27/2024]
Abstract
Rising ocean temperatures due to global warming pose a significant threat to the bay scallop aquaculture industry. Understanding the mechanisms of thermotolerance in bay scallops is crucial for developing thermotolerant breeds. Our prior research identified Arg0230340.1, part of the positive cofactor 4 (PC4) family, as a key gene associated with the thermotolerance index Arrhenius break temperature (ABT) in bay scallops. Further validation through RNA interference (RNAi) reinforced PC4's role in thermotolerance, offering a solid basis for investigating thermal response mechanisms in these scallops. In this study, we performed a comparative transcriptomic analysis on the temperature-sensitive hearts of bay scallops after siRNA-mediated RNAi targeting Arg0230340.1, to delve into the detailed molecular mechanism of PC4's participation in thermotolerance regulation. The analysis revealed that silencing Arg0230340.1 significantly reduced the expression of mitochondrial tRNA and rRNA, potentially affecting mitochondrial function and the heart's blood supply capacity. Conversely, the up-regulation of genes involved in energy metabolism, RNA polymerase II (RNAPII)-mediated basal transcription, and aminoacyl-tRNA synthesis pathways points to an intrinsic protective response, providing energy and substrates for damage repair and maintenance of essential functions under stress. GO and KEGG enrichment analyses indicated that the up-regulated genes were primarily associated with energy metabolism and spliceosome pathways, likely contributing to myocardial remodeling post-Arg0230340.1 knockdown. Down-regulated genes were enriched in ion channel pathways, particularly those for Na+, K+, and Ca2+ channels, whose dysfunction could disrupt normal myocardial bioelectric activity. The impaired cardiac performance resulting from RNAi targeting Arg0230340.1 reduced the cardiac workload in scallop hearts, thus affecting myocardial oxygen consumption and thermotolerance. We propose a hypothetical mechanism where PC4 down-regulation impairs cardiac bioelectric activity, leading to decreased thermotolerance in bay scallops, providing theoretical guidance for breeding thermotolerant scallop varieties and developing strategies for sustainable aquaculture in the face of long-term environmental changes.
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Affiliation(s)
- Jiaxi Chang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Ancheng Liu
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Junhao Zhang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Longfei Chu
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Xiujiang Hou
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, China
| | - Xiaoting Huang
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao Marine Science and Technology Center, Qingdao 266237, China
| | - Qiang Xing
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao Marine Science and Technology Center, Qingdao 266237, China.
| | - Zhenmin Bao
- MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao 266003, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao Marine Science and Technology Center, Qingdao 266237, China
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3
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Peng Z, Wang S, Wen D, Mei Z, Zhang H, Liao S, Lv L, Li C. FEN1 upregulation mediated by SUMO2 via antagonizing proteasomal degradation promotes hepatocellular carcinoma stemness. Transl Oncol 2024; 44:101916. [PMID: 38513457 PMCID: PMC10966306 DOI: 10.1016/j.tranon.2024.101916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 01/22/2024] [Accepted: 02/15/2024] [Indexed: 03/23/2024] Open
Abstract
PURPOSE Metastasis of hepatocellular carcinoma (HCC) critically impacts the survival prognosis of patients, with the pivotal role of hepatocellular carcinoma stem cells in initiating invasive metastatic behaviors. The Flap Endonuclease 1 (FEN1) is delineated as a metallonuclease, quintessential for myriad cellular processes including DNA replication, DNA synthesis, DNA damage rectification, Okazaki fragment maturation, baseexcision repair, and the preservation of genomic stability. Furthermore, it has been recognized as an oncogene in a diverse range of malignancies. Our antecedent research has highlighted a pronounced overexpression of protein FEN1 in hepatocellular carcinoma, where it amplifies the invasiveness and metastatic potential of liver cancer cells. However, its precise role in liver cancer stem cells (LCSCs) remains an enigma and requires further investigation. METHODS To rigorously evaluate the stemness attributes of LCSCs, we employed sphere formation assays and flow cytometric evaluations. Both CD133+ and CD133- cell populations were discerningly isolated utilizing immunomagnetic bead separation techniques. The expression levels of pertinent genes were assayed via real-time quantitative PCR (RT-qPCR) and western blot analyses, while the expression profiles in hepatocellular carcinoma tissues were gauged using immunohistochemistry. Subsequent immunoprecipitation, in conjunction with mass spectrometry, ascertained the concurrent binding of proteins FEN1 and Small ubiquitin-related modifier 2 (SUMO2) in HCC cells. Lastly, the impact of SUMO2 on proteasomal degradation pathway of FEN1 was validated by supplementing MG132. RESULTS Our empirical findings substantiate that protein FEN1 is profusely expressed in spheroids and CD133+ cells. In vitro investigations demonstrate that the upregulation of protein FEN1 unequivocally augments the stemness of LCSCs. In a congruent in vivo context, elevation of FEN1 noticeably enhances the tumorigenic potential of LCSCs. Conversely, inhibiting protein FEN1 resulted in a marked reduction in LCSC stemness. From a mechanistic perspective, there exists a salient positive correlation between the protein expression of FEN1 and SUMO2 in liver cancer tissues. Furthermore, the level of SUMO2-mediated modification of FEN1 is pronouncedly elevated in LCSCs. Interestingly, SUMO2 has the ability to bind to FEN1, leading to a inhibition in the proteasomal degradation pathway of FEN1 and an enhancement in its protein expression. However, it is noteworthy that this interaction does not affect the mRNA level of FEN1. CONCLUSION In summation, our research elucidates that protein FEN1 is an effector in augmenting the stemness of LCSCs. Consequently, strategic attenuation of protein FEN1 might proffer a pioneering approach for the efficacious elimination of LCSCs.
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Affiliation(s)
- Zhenxiang Peng
- Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Linjiang Road, Yuzhong District, Chongqing 400010, PR China
| | - Shuling Wang
- Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Linjiang Road, Yuzhong District, Chongqing 400010, PR China
| | - Diguang Wen
- Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Linjiang Road, Yuzhong District, Chongqing 400010, PR China
| | - Zhechuan Mei
- Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Linjiang Road, Yuzhong District, Chongqing 400010, PR China.
| | - Hao Zhang
- Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Linjiang Road, Yuzhong District, Chongqing 400010, PR China.
| | - Shengtao Liao
- Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Linjiang Road, Yuzhong District, Chongqing 400010, PR China.
| | - Lin Lv
- Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Linjiang Road, Yuzhong District, Chongqing 400010, PR China.
| | - Chuanfei Li
- Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Linjiang Road, Yuzhong District, Chongqing 400010, PR China.
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4
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Hu J, Gao X, Gu M, Sun Y, Dong Y, Wang GL. Target mediated bioreaction to engineer surface vacancy effect on Bi 2O 2S nanosheets for photoelectrochemical detection of FEN1. Anal Chim Acta 2024; 1301:342467. [PMID: 38553124 DOI: 10.1016/j.aca.2024.342467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/28/2024] [Accepted: 03/10/2024] [Indexed: 04/02/2024]
Abstract
Photoelectrochemistry represents a promising technique for bioanalysis, though its application for the detection of Flap endonuclease 1 (FEN1) has not been tapped. Herein, this work reports the exploration of creating oxygen vacancies (Ov) in situ onto the surface of Bi2O2S nanosheets via the attachment of dopamine (DA), which underlies a new anodic PEC sensing strategy for FEN1 detection in label-free, immobilization-free and high-throughput modes. In connection to the target-mediated rolling circle amplification (RCA) reaction for modulating the release of the DA aptamer to capture DA, the detection system showed good performance toward FEN1 analysis with a linear detection range of 0.001-10 U/mL and a detection limit of 1.4 × 10-4 U/mL (S/N = 3). This work features the bioreaction engineered surface vacancy effect of Bi2O2S nanosheets as a PEC sensing strategy, which allows a simple, easy to perform, sensitive and selective method for the detection of FEN1. This sensing strategy might have wide applications in versatile bioasssays, considering the diversity of a variety of biological reactions may produce the DA aptamer.
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Affiliation(s)
- Jiangwei Hu
- Key Laboratory of Synthetic and Biological Colloids (Ministry of Education), School of Chemical and Material Engineering, Jiangnan University, Wuxi, 214122, China
| | - Xin Gao
- Key Laboratory of Synthetic and Biological Colloids (Ministry of Education), School of Chemical and Material Engineering, Jiangnan University, Wuxi, 214122, China
| | - Mengmeng Gu
- Key Laboratory of Synthetic and Biological Colloids (Ministry of Education), School of Chemical and Material Engineering, Jiangnan University, Wuxi, 214122, China
| | - Yuanyuan Sun
- Key Laboratory of Synthetic and Biological Colloids (Ministry of Education), School of Chemical and Material Engineering, Jiangnan University, Wuxi, 214122, China
| | - Yuming Dong
- Key Laboratory of Synthetic and Biological Colloids (Ministry of Education), School of Chemical and Material Engineering, Jiangnan University, Wuxi, 214122, China
| | - Guang-Li Wang
- Key Laboratory of Synthetic and Biological Colloids (Ministry of Education), School of Chemical and Material Engineering, Jiangnan University, Wuxi, 214122, China.
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Leriche M, Bonnet C, Jana J, Chhetri G, Mennour S, Martineau S, Pennaneach V, Busso D, Veaute X, Bertrand P, Lambert S, Somyajit K, Uguen P, Vagner S. 53BP1 interacts with the RNA primer from Okazaki fragments to support their processing during unperturbed DNA replication. Cell Rep 2023; 42:113412. [PMID: 37963016 DOI: 10.1016/j.celrep.2023.113412] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 08/03/2023] [Accepted: 10/25/2023] [Indexed: 11/16/2023] Open
Abstract
RNA-binding proteins (RBPs) are found at replication forks, but their direct interaction with DNA-embedded RNA species remains unexplored. Here, we report that p53-binding protein 1 (53BP1), involved in the DNA damage and replication stress response, is an RBP that directly interacts with Okazaki fragments in the absence of external stress. The recruitment of 53BP1 to nascent DNA shows susceptibility to in situ ribonuclease A treatment and is dependent on PRIM1, which synthesizes the RNA primer of Okazaki fragments. Conversely, depletion of FEN1, resulting in the accumulation of uncleaved RNA primers, increases 53BP1 levels at replication forks, suggesting that RNA primers contribute to the recruitment of 53BP1 at the lagging DNA strand. 53BP1 depletion induces an accumulation of S-phase poly(ADP-ribose), which constitutes a sensor of unligated Okazaki fragments. Collectively, our data indicate that 53BP1 is anchored at nascent DNA through its RNA-binding activity, highlighting the role of an RNA-protein interaction at replication forks.
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Affiliation(s)
- Melissa Leriche
- Institut Curie, PSL Research University, CNRS UMR 3348, INSERM U1278, Orsay, France; Université Paris-Saclay, CNRS UMR 3348, INSERM U1278, Orsay, France; Equipe labellisée Ligue contre le Cancer, Orsay, France
| | - Clara Bonnet
- Institut Curie, PSL Research University, CNRS UMR 3348, INSERM U1278, Orsay, France; Université Paris-Saclay, CNRS UMR 3348, INSERM U1278, Orsay, France; Equipe labellisée Ligue contre le Cancer, Orsay, France
| | - Jagannath Jana
- Institut Curie, PSL Research University, CNRS UMR 3348, INSERM U1278, Orsay, France; Université Paris-Saclay, CNRS UMR 3348, INSERM U1278, Orsay, France; Equipe labellisée Ligue contre le Cancer, Orsay, France
| | - Gita Chhetri
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Sabrina Mennour
- Institut Curie, PSL Research University, CNRS UMR 3348, INSERM U1278, Orsay, France; Université Paris-Saclay, CNRS UMR 3348, INSERM U1278, Orsay, France; Equipe labellisée Ligue contre le Cancer, Orsay, France
| | - Sylvain Martineau
- Institut Curie, PSL Research University, CNRS UMR 3348, INSERM U1278, Orsay, France; Université Paris-Saclay, CNRS UMR 3348, INSERM U1278, Orsay, France; Equipe labellisée Ligue contre le Cancer, Orsay, France
| | - Vincent Pennaneach
- Institut Curie, PSL Research University, CNRS UMR 3348, INSERM U1278, Orsay, France; Université Paris-Saclay, CNRS UMR 3348, INSERM U1278, Orsay, France; Equipe labellisée Ligue contre le Cancer, Orsay, France
| | - Didier Busso
- Université Paris Cité, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, iRCM/IBFJ, 92260 Fontenay-aux-Roses, France; Université Paris-Saclay, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, iRCM/IBFJ, 92260 Fontenay-aux-Roses, France
| | - Xavier Veaute
- Université Paris Cité, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, iRCM/IBFJ, 92260 Fontenay-aux-Roses, France; Université Paris-Saclay, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, iRCM/IBFJ, 92260 Fontenay-aux-Roses, France
| | - Pascale Bertrand
- Université Paris Cité, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, iRCM/IBFJ, 92260 Fontenay-aux-Roses, France; Université Paris-Saclay, INSERM, CEA, Stabilité Génétique Cellules Souches et Radiations, iRCM/IBFJ, 92260 Fontenay-aux-Roses, France
| | - Sarah Lambert
- Institut Curie, PSL Research University, CNRS UMR 3348, INSERM U1278, Orsay, France; Université Paris-Saclay, CNRS UMR 3348, INSERM U1278, Orsay, France; Equipe labellisée Ligue contre le Cancer, Orsay, France
| | - Kumar Somyajit
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Patricia Uguen
- Institut Curie, PSL Research University, CNRS UMR 3348, INSERM U1278, Orsay, France; Université Paris-Saclay, CNRS UMR 3348, INSERM U1278, Orsay, France; Equipe labellisée Ligue contre le Cancer, Orsay, France
| | - Stéphan Vagner
- Institut Curie, PSL Research University, CNRS UMR 3348, INSERM U1278, Orsay, France; Université Paris-Saclay, CNRS UMR 3348, INSERM U1278, Orsay, France; Equipe labellisée Ligue contre le Cancer, Orsay, France.
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6
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Sun H, Ma L, Tsai YF, Abeywardana T, Shen B, Zheng L. Okazaki fragment maturation: DNA flap dynamics for cell proliferation and survival. Trends Cell Biol 2023; 33:221-234. [PMID: 35879148 PMCID: PMC9867784 DOI: 10.1016/j.tcb.2022.06.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/28/2022] [Accepted: 06/30/2022] [Indexed: 01/24/2023]
Abstract
Unsuccessful processing of Okazaki fragments leads to the accumulation of DNA breaks which are associated with many human diseases including cancer and neurodegenerative disorders. Recently, Okazaki fragment maturation (OFM) has received renewed attention regarding how unprocessed Okazaki fragments are sensed and repaired, and how inappropriate OFM impacts on genome stability and cell viability, especially in cancer cells. We provide an overview of the highly efficient and faithful canonical OFM pathways and their regulation of genomic integrity and cell survival. We also discuss how cells induce alternative error-prone OFM processes to promote cell survival in response to environmental stresses. Such stress-induced OFM processes may be important mechanisms driving mutagenesis, cellular evolution, and resistance to radio/chemotherapy and targeted therapeutics in human cancers.
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Affiliation(s)
- Haitao Sun
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA
| | - Lingzi Ma
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA
| | - Ya-Fang Tsai
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA
| | - Tharindu Abeywardana
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA
| | - Binghui Shen
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA.
| | - Li Zheng
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, CA 91010, USA.
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7
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Kim S, Kim Y, Kim Y, Yoon S, Lee KY, Lee Y, Kang S, Myung K, Oh CK. PCNA Ser46-Leu47 residues are crucial in preserving genomic integrity. PLoS One 2023; 18:e0285337. [PMID: 37205694 DOI: 10.1371/journal.pone.0285337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/19/2023] [Indexed: 05/21/2023] Open
Abstract
Proliferating cell nuclear antigen (PCNA) is a maestro of DNA replication. PCNA forms a homotrimer and interacts with various proteins, such as DNA polymerases, DNA ligase I (LIG1), and flap endonuclease 1 (FEN1) for faithful DNA replication. Here, we identify the crucial role of Ser46-Leu47 residues of PCNA in maintaining genomic integrity using in vitro, and cell-based assays and structural prediction. The predicted PCNAΔSL47 structure shows the potential distortion of the central loop and reduced hydrophobicity. PCNAΔSL47 shows a defective interaction with PCNAWT leading to defects in homo-trimerization in vitro. PCNAΔSL47 is defective in the FEN1 and LIG1 interaction. PCNA ubiquitination and DNA-RNA hybrid processing are defective in PCNAΔSL47-expressing cells. Accordingly, PCNAΔSL47-expressing cells exhibit an increased number of single-stranded DNA gaps and higher levels of γH2AX, and sensitivity to DNA-damaging agents, highlighting the importance of PCNA Ser46-Leu47 residues in maintaining genomic integrity.
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Affiliation(s)
- Sangin Kim
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, College of Information-Bio Convergence Engineering, Ulsan, Korea
| | - Yeongjae Kim
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, College of Information-Bio Convergence Engineering, Ulsan, Korea
| | - Youyoung Kim
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, College of Information-Bio Convergence Engineering, Ulsan, Korea
| | - Suhyeon Yoon
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Integrated Data Sciences Section, Research Technologies Branch, Bethesda, MD, United States of America
| | - Kyoo-Young Lee
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Department of Biochemistry, College of Medicine, Hallym University, Chuncheon, Gangwon-do, Korea
| | - Yoonsung Lee
- Clinical Research Institute, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Sukhyun Kang
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
| | - Kyungjae Myung
- Institute for Basic Science, Center for Genomic Integrity, Ulsan, Korea
- Ulsan National Institute of Science and Technology, Department of Biomedical Engineering, College of Information-Bio Convergence Engineering, Ulsan, Korea
| | - Chang-Kyu Oh
- Department of Biochemistry, Pusan National University, School of Medicine, Yangsan, Korea
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8
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Tang Q, Liu Y, Liu Y, Zhu F, Yu Q, Chen H, Chen L, Ma S, Xu H, Chen K, Li G. Bombyx mori Flap endonuclease 1 correlates with the repair of ultraviolet-induced DNA damage. JOURNAL OF INSECT PHYSIOLOGY 2022; 142:104424. [PMID: 35878701 DOI: 10.1016/j.jinsphys.2022.104424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
Solar ultraviolet radiation (UV) can cause DNA damage in microorganisms. Flap endonuclease 1 (FEN1) is a structure-specific nuclease and plays important roles in DNA replication and repair. At present, the properties and functions of FEN1 have not been characterized in detail in invertebrates such as Bombyx mori. In this study, Bombyx mori FEN1 (BmFEN1) was expressed in E. coli, and was shown to have nuclease activity that nonspecifically cleaved DNA in vitro. However, inside the cell, BmFEN1 did not cleave DNA randomly. Truncated BmFEN1 missing the nuclear localization signal (346-380 aa) still had the nuclease activity, but was no longer precisely localized to the sites of UV-induced DNA damage. It was further found that BmFEN1 favored the faster repair of UV-damaged DNA. The present study will provide a reference for further understanding the functions of BmFEN1 and UV-induced DNA damage repair mechanisms in insects.
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Affiliation(s)
- Qi Tang
- School of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Yue Liu
- School of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Yutong Liu
- School of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Feifei Zhu
- School of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Qian Yu
- School of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Huiqing Chen
- School of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Liang Chen
- School of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Shangshang Ma
- School of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Huixin Xu
- School of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China
| | - Keping Chen
- School of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China.
| | - Guohui Li
- School of Life Sciences, Jiangsu University, 301# Xuefu Road, Zhenjiang 212013, China.
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9
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Small-Molecule Inhibitors Targeting FEN1 for Cancer Therapy. Biomolecules 2022; 12:biom12071007. [PMID: 35883563 PMCID: PMC9312813 DOI: 10.3390/biom12071007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/15/2022] [Accepted: 07/19/2022] [Indexed: 01/27/2023] Open
Abstract
DNA damage repair plays a key role in maintaining genomic stability and integrity. Flap endonuclease 1 (FEN1) is a core protein in the base excision repair (BER) pathway and participates in Okazaki fragment maturation during DNA replication. Several studies have implicated FEN1 in the regulation of other DNA repair pathways, including homologous recombination repair (HRR) and non-homologous end joining (NHEJ). Abnormal expression or mutation of FEN1 in cells can cause a series of pathological responses, leading to various diseases, including cancers. Moreover, overexpression of FEN1 contributes to drug resistance in several types of cancers. All this supports the hypothesis that FEN1 could be a therapeutic target for cancer treatment. Targeting FEN1 has been verified as an effective strategy in mono or combined treatment of cancer. Small-molecule compounds targeting FEN1 have also been developed and detected in cancer regression. In this review, we summarize the recent development of small-molecule inhibitors targeting FEN1 in recent years, thereby expanding their therapeutic potential and application.
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10
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Sun H, Lu Z, Singh A, Zhou Y, Zheng E, Zhou M, Wang J, Wu X, Hu Z, Gu Z, Campbell JL, Zheng L, Shen B. Error-prone, stress-induced 3' flap-based Okazaki fragment maturation supports cell survival. Science 2021; 374:1252-1258. [PMID: 34855483 PMCID: PMC8852821 DOI: 10.1126/science.abj1013] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
How cells with DNA replication defects acquire mutations that allow them to escape apoptosis under environmental stress is a long-standing question. Here, we report that an error-prone Okazaki fragment maturation (OFM) pathway is activated at restrictive temperatures in rad27Δ yeast cells. Restrictive temperature stress activated Dun1, facilitating transformation of unprocessed 5′ flaps into 3′ flaps, which were removed by 3′ nucleases, including DNA polymerase δ (Polδ). However, at certain regions, 3′ flaps formed secondary structures that facilitated 3′ end extension rather than degradation, producing alternative duplications with short spacer sequences, such as pol3 internal tandem duplications. Consequently, little 5′ flap was formed, suppressing rad27Δ-induced lethality at restrictive temperatures. We define a stress-induced, error-prone OFM pathway that generates mutations that counteract replication defects and drive cellular evolution and survival.
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Affiliation(s)
- Haitao Sun
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010
| | - Zhaoning Lu
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010
| | - Amanpreet Singh
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010
| | - Yajing Zhou
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010
| | - Eric Zheng
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010
- Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, CA 93106
| | - Mian Zhou
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010
| | - Jinhui Wang
- Department of Molecular and Cellular Biology, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010
| | - Xiwei Wu
- Department of Molecular and Cellular Biology, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010
| | - Zunsong Hu
- Department of Computational and Quantitative Medicine, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010
| | - Zhaohui Gu
- Department of Computational and Quantitative Medicine, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010
| | - Judith L. Campbell
- Divisions of Chemistry and Chemical Engineering and Biology and Biological Engineering California Institute of Technology, Pasadena, CA 91125, USA
| | - Li Zheng
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010
| | - Binghui Shen
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010
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11
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Xu X, Shi R, Zheng L, Guo Z, Wang L, Zhou M, Zhao Y, Tian B, Truong K, Chen Y, Shen B, Hua Y, Xu H. SUMO-1 modification of FEN1 facilitates its interaction with Rad9-Rad1-Hus1 to counteract DNA replication stress. J Mol Cell Biol 2019; 10:460-474. [PMID: 30184152 PMCID: PMC6231531 DOI: 10.1093/jmcb/mjy047] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 09/03/2018] [Indexed: 01/25/2023] Open
Abstract
Human flap endonuclease 1 (FEN1) is a structure-specific, multi-functional endonuclease essential for DNA replication and repair. We and others have shown that during DNA replication, FEN1 processes Okazaki fragments via its interaction with the proliferating cell nuclear antigen (PCNA). Alternatively, in response to DNA damage, FEN1 interacts with the PCNA-like Rad9–Rad1–Hus1 complex instead of PCNA to engage in DNA repair activities, such as homology-directed repair of stalled DNA replication forks. However, it is unclear how FEN1 is able to switch between these interactions and its roles in DNA replication and DNA repair. Here, we report that FEN1 undergoes SUMOylation by SUMO-1 in response to DNA replication fork-stalling agents, such as UV irradiation, hydroxyurea, and mitomycin C. This DNA damage-induced SUMO-1 modification promotes the interaction of FEN1 with the Rad9–Rad1–Hus1 complex. Furthermore, we found that FEN1 mutations that prevent its SUMO-1 modification also impair its ability to interact with HUS1 and to rescue stalled replication forks. These impairments lead to the accumulation of DNA damage and heightened sensitivity to fork-stalling agents. Altogether, our findings suggest an important role of the SUMO-1 modification of FEN1 in regulating its roles in DNA replication and repair.
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Affiliation(s)
- Xiaoli Xu
- Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
| | - Rongyi Shi
- Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
| | - Li Zheng
- Department of Cancer Genetics and Epigenetics, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, USA
| | - Zhigang Guo
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology and College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Liangyan Wang
- Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
| | - Mian Zhou
- Department of Cancer Genetics and Epigenetics, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, USA
| | - Ye Zhao
- Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
| | - Bing Tian
- Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
| | - Khue Truong
- Department of Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, USA
| | - Yuan Chen
- Department of Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, USA
| | - Binghui Shen
- Department of Cancer Genetics and Epigenetics, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, USA
| | - Yuejin Hua
- Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
| | - Hong Xu
- Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
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12
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Li C, Zhou D, Hong H, Yang S, Zhang L, Li S, Hu P, Ren H, Mei Z, Tang H. TGFβ1- miR-140-5p axis mediated up-regulation of Flap Endonuclease 1 promotes epithelial-mesenchymal transition in hepatocellular carcinoma. Aging (Albany NY) 2019; 11:5593-5612. [PMID: 31402791 PMCID: PMC6710057 DOI: 10.18632/aging.102140] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 07/30/2019] [Indexed: 12/21/2022]
Abstract
Flap Endonuclease 1 (FEN1) is a known oncogene in an array of cancers, but its role in hepatocellular carcinoma (HCC) remains obscure. In this study, we report that FEN1 expression was elevated in the Cancer Genome Atlas (TCGA) database which was verified in HCC tissue and hepatoma cell lines. Pearson correlation analysis indicated that FEN1 was involved in HCC metastasis. We demonstrated that FEN1 silencing inhibits HCC cell epithelial-mesenchymal transition (EMT), invasion and migration in vitro and significantly suppressed tumor growth and metastasis in vivo. Conversely, FEN1 overexpression in HCC cells enhanced these metastatic processes. We further confirmed that FEN1 was a direct target of miR-140-5p, which was down-regulated in HCC tissues, and negatively correlated with FEN1 expression. Moreover, low miR-140-5p levels and high FEN1 expression predicted a poor clinical outcome. The effects of FEN1 overexpression could be partially abolished by miR-140-5p. miR-140-5p down-regulation and FEN1 overexpression were observed in a TGFβ1 induced EMT model. TGFβ1 mediated EMT could be blocked by miR-140-5p overexpression or FEN1 silencing. Taken together, our findings suggest that FEN1 is regulated by the TGFβ1- miR-140-5p axis and promotes EMT in HCC.
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Affiliation(s)
- Chuanfei Li
- Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Di Zhou
- Department of Radiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 4001016, China
| | - Hao Hong
- Department of Orthopaedics, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Shuangyan Yang
- Department of Infectious Diseases, Institute for Viral Hepatitis, The Key Laboratory of Molecular Biology for Infectious Diseases, Chinese Ministry of Education, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Li Zhang
- Department of Infectious Diseases, Institute for Viral Hepatitis, The Key Laboratory of Molecular Biology for Infectious Diseases, Chinese Ministry of Education, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Shiying Li
- Department of Infectious Diseases, Institute for Viral Hepatitis, The Key Laboratory of Molecular Biology for Infectious Diseases, Chinese Ministry of Education, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Peng Hu
- Department of Infectious Diseases, Institute for Viral Hepatitis, The Key Laboratory of Molecular Biology for Infectious Diseases, Chinese Ministry of Education, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Hong Ren
- Department of Infectious Diseases, Institute for Viral Hepatitis, The Key Laboratory of Molecular Biology for Infectious Diseases, Chinese Ministry of Education, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Zhechuan Mei
- Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
| | - Hui Tang
- Department of Infectious Diseases, Institute for Viral Hepatitis, The Key Laboratory of Molecular Biology for Infectious Diseases, Chinese Ministry of Education, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
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13
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Li N, Zhao L, Guo C, Liu C, Liu Y. Identification of a novel DNA repair-related prognostic signature predicting survival of patients with hepatocellular carcinoma. Cancer Manag Res 2019; 11:7473-7484. [PMID: 31496805 PMCID: PMC6689532 DOI: 10.2147/cmar.s204864] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 07/19/2019] [Indexed: 12/14/2022] Open
Abstract
Purpose Hepatocellular carcinoma (HCC) is the sixth most lethal neoplasm worldwide. Traditional biomarkers often exploit the relationship between a certain gene and cancer progression, but they cannot predict patient survival or prognosis accurately. We aim to construct a new DNA repair-related gene signature that combines several genes to improve prognosis prediction in HCC. Methods We selected an HCC mRNA sequencing (mRNA-seq) dataset (n=365) from The Cancer Genome Atlas (TCGA), and gene set enrichment analysis (GSEA) was used to explore bioinformatics information and further screen genes. We then built a gene signature based on the Cox proportional hazards regression model. Results GSEA revealed that the hallmark DNA repair gene set was significantly upregulated in the tumor phenotype. A set of seven genes, namely, ADA, FEN1, POLR2G, SAC3D1, SEC61A1, SF3A3, and UPF3B, were significantly a
ssociated with overall survival (OS) and used to form a gene signature. The signature risk score was calculated and used to divide patients into high‐ and low‐risk groups. The high-risk group showed worse prognosis (log-rank test p<0.0001). Univariate and multivariate Cox regression analysis showed that the prognostic performance of this risk score signature was robust in different subgroups based on clinicopathological features, with p-values <0.05 (HR=2.38, 95% CI (confidence interval) =1.355–4.184), indicating that it can serve as an independent prognostic indicator. Conclusion We developed and identified a seven‐gene signature related to the DNA repair process that can predict survival in HCC. It can be used as an effective classification tool and to guide clinical treatment.
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Affiliation(s)
- Na Li
- Department of Central Laboratory, Shenyang Tenth People's Hospital, Shenyang Chest Hospital, Shenyang, Liaoning, People's Republic of China
| | - Lan Zhao
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, Liaoning, People's Republic of China
| | - Chunyan Guo
- Department of Pharmacy, Shenyang Tenth People's Hospital, Shenyang Chest Hospital, Shenyang, Liaoning, People's Republic of China
| | - Chang Liu
- Department of Thoracic Surgery, Shenyang Tenth People's Hospital, Shenyang Chest Hospital, Shenyang, Liaoning, People's Republic of China
| | - Yongyu Liu
- Department of Thoracic Surgery, Shenyang Tenth People's Hospital, Shenyang Chest Hospital, Shenyang, Liaoning, People's Republic of China
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14
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Ben-Salem S, Robbins SM, Sobreira NLM, Lyon A, Al-Shamsi AM, Islam BK, Akawi NA, John A, Thachillath P, Hamed SA, Valle D, Ali BR, Al-Gazali L. Defect in phosphoinositide signalling through a homozygous variant in PLCB3 causes a new form of spondylometaphyseal dysplasia with corneal dystrophy. J Med Genet 2018; 55:122-130. [PMID: 29122926 PMCID: PMC8215682 DOI: 10.1136/jmedgenet-2017-104827] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 09/19/2017] [Accepted: 10/06/2017] [Indexed: 02/05/2023]
Abstract
BACKGROUND Bone dysplasias are a large group of disorders affecting the growth and structure of the skeletal system. METHODS In the present study, we report the clinical and molecular delineation of a new form of syndromic autosomal recessive spondylometaphyseal dysplasia (SMD) in two Emirati first cousins. They displayed postnatal growth deficiency causing profound limb shortening with proximal and distal segments involvement, narrow chest, radiological abnormalities involving the spine, pelvis and metaphyses, corneal clouding and intellectual disability. Whole genome homozygosity mapping localised the genetic cause to 11q12.1-q13.1, a region spanning 19.32 Mb with ~490 genes. Using whole exome sequencing, we identified four novel homozygous variants within the shared block of homozygosity. Pathogenic variants in genes involved in phospholipid metabolism, such as PLCB4 and PCYT1A, are known to cause bone dysplasia with or without eye anomalies, which led us to select PLCB3 as a strong candidate. This gene encodes phospholipase C β 3, an enzyme that converts phosphatidylinositol 4,5 bisphosphate (PIP2) to inositol 1,4,5 triphosphate (IP3) and diacylglycerol. RESULTS The identified variant (c.2632G>T) substitutes a serine for a highly conserved alanine within the Ha2' element of the proximal C-terminal domain. This disrupts binding of the Ha2' element to the catalytic core and destabilises PLCB3. Here we show that this hypomorphic variant leads to elevated levels of PIP2 in patient fibroblasts, causing disorganisation of the F-actin cytoskeleton. CONCLUSIONS Our results connect a homozygous loss of function variant in PLCB3 with a new SMD associated with corneal dystrophy and developmental delay (SMDCD).
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Affiliation(s)
- Salma Ben-Salem
- Department of Pathology, College of Medicine and Heath Sciences, University Al-Ain, Al Ain, AbuDhabi, United Arab Emirates
| | - Sarah M Robbins
- Human genetics and Molecular Biology, Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Nara LM Sobreira
- Human genetics and Molecular Biology, Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Angeline Lyon
- Chemistry and Biological Sciences, West Lafayette, USA
| | - Aisha M Al-Shamsi
- Department of Paediatrics, Tawam Hospital, Al-Ain, United Arab Emirates
| | - Barira K Islam
- Department of Paediatrics, College of Medicine and Heath Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Nadia A Akawi
- Division of Cardiovascular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, Oxfordshire, UK
| | - Anne John
- Department of Pathology, College of Medicine and Heath Sciences, University Al-Ain, Al Ain, AbuDhabi, United Arab Emirates
| | - Pramathan Thachillath
- Department of Paediatrics, College of Medicine and Heath Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Sania Al Hamed
- Department of Paediatrics, College of Medicine and Heath Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - David Valle
- Human genetics and Molecular Biology, Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Bassam R Ali
- Department of Pathology, College of Medicine and Heath Sciences, University Al-Ain, Al Ain, AbuDhabi, United Arab Emirates
| | - Lihadh Al-Gazali
- Department of Paediatrics, College of Medicine and Heath Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
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15
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Zhang K, Keymeulen S, Nelson R, Tong TR, Yuan YC, Yun X, Liu Z, Lopez J, Raz DJ, Kim JY. Overexpression of Flap Endonuclease 1 Correlates with Enhanced Proliferation and Poor Prognosis of Non-Small-Cell Lung Cancer. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 188:242-251. [PMID: 29037854 DOI: 10.1016/j.ajpath.2017.09.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 09/14/2017] [Accepted: 09/21/2017] [Indexed: 01/31/2023]
Abstract
Flap endonuclease 1 (FEN1) plays a crucial role in both DNA replication and damage repair. In this study, FEN1 expression and its clinical-pathologic significance in non-small-cell lung cancer (NSCLC) was investigated. Quantitative RT-PCR and immunohistochemistry analysis identified that both FEN1 mRNA and protein were highly overexpressed in about 36% of 136 cancer tissues compared to adjacent tissues, in which FEN1 was generally undetectable. Notably, patients with FEN1-overexpressed cancers were prone to have poor differentiation and poor prognosis. A strong positive correlation between the levels of FEN1 and Ki-67 staining was identified in these NSCLC tissues (r = 0.485), suggesting overexpressed FEN1 conferred a proliferative advantage to NSCLC. Furthermore, knockdown of FEN1 resulted in G1/S or G2/M phase cell cycle arrest and suppressed in vitro cellular proliferation in NSCLC cancer cells. Consistently, a selective FEN1 inhibitor was shown to effectively inhibit cellular proliferation of NSCLC cells in a dose-dependent manner. Additionally, knockdown of FEN1 significantly attenuated homologous DNA repair efficiency and enhanced cytotoxic effects of cisplatin in NSCLC cells. Taken together, these findings have indicated that overexpressed FEN1 represents a prognostic biomarker and potential therapeutic target for NSCLC treatment, which warrants further study.
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Affiliation(s)
- Keqiang Zhang
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California.
| | - Sawa Keymeulen
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California
| | - Rebecca Nelson
- Division of Biostatistics, City of Hope National Medical Center, Duarte, California
| | - Tommy R Tong
- Department of Pathology, City of Hope National Medical Center, Duarte, California
| | - Yate-Ching Yuan
- Bioinformatics Core Facility, Department of Molecular Medicine, City of Hope National Medical Center, Duarte, California
| | - Xinwei Yun
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California
| | - Zheng Liu
- Bioinformatics Core Facility, Department of Molecular Medicine, City of Hope National Medical Center, Duarte, California
| | - Joshua Lopez
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California
| | - Dan J Raz
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California
| | - Jae Y Kim
- Division of Thoracic Surgery, City of Hope National Medical Center, Duarte, California.
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16
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Sisakova A, Altmannova V, Sebesta M, Krejci L. Role of PCNA and RFC in promoting Mus81-complex activity. BMC Biol 2017; 15:90. [PMID: 28969641 PMCID: PMC5625722 DOI: 10.1186/s12915-017-0429-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Accepted: 09/15/2017] [Indexed: 01/23/2023] Open
Abstract
Background Proper DNA replication is essential for faithful transmission of the genome. However, replication stress has serious impact on the integrity of the cell, leading to stalling or collapse of replication forks, and has been determined as a driving force of carcinogenesis. Mus81-Mms4 complex is a structure-specific endonuclease previously shown to be involved in processing of aberrant replication intermediates and promotes POLD3-dependent DNA synthesis via break-induced replication. However, how replication components might be involved in this process is not known. Results Herein, we show the interaction and robust stimulation of Mus81-Mms4 nuclease activity by heteropentameric replication factor C (RFC) complex, the processivity factor of replicative DNA polymerases that is responsible for loading of proliferating cell nuclear antigen (PCNA) during DNA replication and repair. This stimulation is enhanced by RFC-dependent ATP hydrolysis and by PCNA loading on the DNA. Moreover, this stimulation is not specific to Rfc1, the largest of subunit of this complex, thus indicating that alternative clamp loaders may also play a role in the stimulation. We also observed a targeting of Mus81 by RFC to the nick-containing DNA substrate and we provide further evidence that indicates cooperation between Mus81 and the RFC complex in the repair of DNA lesions generated by various DNA-damaging agents. Conclusions Identification of new interacting partners and modulators of Mus81-Mms4 nuclease, RFC, and PCNA imply the cooperation of these factors in resolution of stalled replication forks and branched DNA structures emanating from the restarted replication forks under conditions of replication stress. Electronic supplementary material The online version of this article (doi:10.1186/s12915-017-0429-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alexandra Sisakova
- Department of Biology, Masaryk University, Kamenice 5/A7, CZ-62500, Brno, Czech Republic.,National Centre for Biomolecular Research, Masaryk University, Kamenice 5/A4, CZ-62500, Brno, Czech Republic.,International Clinical Research Center, Center for Biomolecular and Cellular Engineering, St. Anne's University Hospital Brno, Pekarska 53, CZ-656 91, Brno, Czech Republic
| | - Veronika Altmannova
- Department of Biology, Masaryk University, Kamenice 5/A7, CZ-62500, Brno, Czech Republic.,International Clinical Research Center, Center for Biomolecular and Cellular Engineering, St. Anne's University Hospital Brno, Pekarska 53, CZ-656 91, Brno, Czech Republic
| | - Marek Sebesta
- Department of Biology, Masaryk University, Kamenice 5/A7, CZ-62500, Brno, Czech Republic.,National Centre for Biomolecular Research, Masaryk University, Kamenice 5/A4, CZ-62500, Brno, Czech Republic.,Present address: Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Lumir Krejci
- Department of Biology, Masaryk University, Kamenice 5/A7, CZ-62500, Brno, Czech Republic. .,National Centre for Biomolecular Research, Masaryk University, Kamenice 5/A4, CZ-62500, Brno, Czech Republic. .,International Clinical Research Center, Center for Biomolecular and Cellular Engineering, St. Anne's University Hospital Brno, Pekarska 53, CZ-656 91, Brno, Czech Republic.
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17
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Zhou L, Dai H, Wu J, Zhou M, Yuan H, Du J, Yang L, Wu X, Xu H, Hua Y, Xu J, Zheng L, Shen B. Role of FEN1 S187 phosphorylation in counteracting oxygen-induced stress and regulating postnatal heart development. FASEB J 2016; 31:132-147. [PMID: 27694478 DOI: 10.1096/fj.201600631r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 09/16/2016] [Indexed: 12/22/2022]
Abstract
Flap endonuclease 1 (FEN1) phosphorylation is proposed to regulate the action of FEN1 in DNA repair as well as Okazaki fragment maturation. However, the biologic significance of FEN1 phosphorylation in response to DNA damage remains unknown. Here, we report an in vivo role for FEN1 phosphorylation, using a mouse line carrying S187A FEN1, which abolishes FEN1 phosphorylation. Although S187A mouse embryonic fibroblast cells showed normal proliferation under low oxygen levels (2%), the mutant cells accumulated oxidative DNA damage, activated DNA damage checkpoints, and showed G1-phase arrest at atmospheric oxygen levels (21%). This suggests an essential role for FEN1 phosphorylation in repairing oxygen-induced DNA damage and maintaining proper cell cycle progression. Consistently, the mutant cardiomyocytes showed G1-phase arrest due to activation of the p53-mediated DNA damage response at the neonatal stage, which reduces the proliferation potential of the cardiomyocytes and impairs heart development. Nearly 50% of newborns with the S187A mutant died in the first week due to failure to undergo the peroxisome proliferator-activated receptor signaling-dependent switch from glycolysis to fatty acid oxidation. The adult mutant mice developed dilated hearts and showed significantly shorter life spans. Altogether, our results reveal an important role of FEN1 phosphorylation to counteract oxygen-induced stress in the heart during the fetal-to-neonatal transition.-Zhou, L., Dai, H., Wu, J., Zhou, M., Yuan, H., Du, J., Yang, L., Wu, X., Xu, H., Hua, Y., Xu, J., Zheng, L., Shen, B. Role of FEN1 S187 phosphorylation in counteracting oxygen-induced stress and regulating postnatal heart development.
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Affiliation(s)
- Lina Zhou
- College of Life Sciences and Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.,Department of Cancer Genetics and Epigenetics and Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Huifang Dai
- Department of Cancer Genetics and Epigenetics and Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Jian Wu
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California, USA
| | - Mian Zhou
- Department of Cancer Genetics and Epigenetics and Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Hua Yuan
- Department of Diagnostic Ultrasound, Shaoxing Women and Children's Hospital, Shaoxing, China
| | - Juan Du
- Department of Cancer Genetics and Epigenetics and Beckman Research Institute of City of Hope, Duarte, California, USA
| | - Lu Yang
- Department of Molecular and Cellular Biology, Beckman Research Institute of City of Hope, Duarte, California, USA; and
| | - Xiwei Wu
- Department of Molecular and Cellular Biology, Beckman Research Institute of City of Hope, Duarte, California, USA; and
| | - Hong Xu
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
| | - Yuejin Hua
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
| | - Jian Xu
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California, USA
| | - Li Zheng
- Department of Cancer Genetics and Epigenetics and Beckman Research Institute of City of Hope, Duarte, California, USA;
| | - Binghui Shen
- Department of Cancer Genetics and Epigenetics and Beckman Research Institute of City of Hope, Duarte, California, USA;
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18
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The FEN1 L209P mutation interferes with long-patch base excision repair and induces cellular transformation. Oncogene 2016; 36:194-207. [PMID: 27270424 PMCID: PMC5140775 DOI: 10.1038/onc.2016.188] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 04/12/2016] [Accepted: 04/12/2016] [Indexed: 12/20/2022]
Abstract
Flap endonuclease-1 (FEN1) is a multifunctional, structure-specific nuclease that has a critical role in maintaining human genome stability. FEN1 mutations have been detected in human cancer specimens and have been suggested to cause genomic instability and cancer predisposition. However, the exact relationship between FEN1 deficiency and cancer susceptibility remains unclear. In the current work, we report a novel colorectal cancer-associated FEN1 mutation, L209P. This mutant protein lacks the FEN, exonuclease (EXO) and gap endonuclease (GEN) activities of FEN1 but retains DNA-binding affinity. The L209P FEN1 variant interferes with the function of the wild-type FEN1 enzyme in a dominant-negative manner and impairs long-patch base excision repair in vitro and in vivo. Expression of L209P FEN1 sensitizes cells to DNA damage, resulting in endogenous genomic instability and cellular transformation, as well as tumor growth in a mouse xenograft model. These data indicate that human cancer-associated genetic alterations in the FEN1 gene can contribute substantially to cancer development.
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19
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Jiao X, Wu Y, Zhou L, He J, Yang C, Zhang P, Hu R, Luo C, Du J, Fu J, Shi J, He R, Li D, Jun W. Variants and haplotypes in Flap endonuclease 1 and risk of gallbladder cancer and gallstones: a population-based study in China. Sci Rep 2015; 5:18160. [PMID: 26668074 PMCID: PMC4678911 DOI: 10.1038/srep18160] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/13/2015] [Indexed: 12/16/2022] Open
Abstract
The role of FEN1 genetic variants on gallstone and gallbladder cancer susceptibility is unknown. FEN1 SNPs were genotyped using the polymerase chain reaction-restriction fragment length polymorphism method in blood samples from 341 gallbladder cancer patients and 339 healthy controls. The distribution of FEN1-69G > A genotypes among controls (AA, 20.6%; GA, 47.2% and GG 32.2%) was significantly different from that among gallbladder cancer cases (AA, 11.1%; GA, 48.1% and GG, 40.8%), significantly increased association with gallbladder cancer was observed for subjects with both the FEN1-69G > A GA (OR = 1.73, 95% CI = 1.01-2.63) and the FEN1-69G > A GG (OR = 2.29, 95% CI = 1.31-3.9). The distribution of FEN1 -4150T genotypes among controls (TT, 21.8%;GT, 49.3% and GG 28.9%) was significantly different from that among gallbladder cancer cases (TT, 12.9%; GT, 48.4% and GG 38.7%), significantly increased association with gallbladder cancer was observed for subjects with both the FEN1-4150T GT(OR = 1.93, 95% CI = 1.04-2.91) and the FEN1-4150T GG(OR = 2.56, 95% CI = 1.37-5.39). A significant trend towards increased association with gallbladder cancer was observed with potentially higher-risk FEN1-69G > A genotypes (P < 0.001, χ2 trend test) and FEN14150G > T (P < 0.001, χ2 trend test) in gallstone presence but not in gallstone absence (P = 0.81, P = 0.89, respectively). In conclusion, this study revealed firstly that FEN1 polymorphisms and haplotypes are associated with gallbladder cancer risk.
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Affiliation(s)
- Xingyuan Jiao
- Department of General Surgery, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080, China
- Department of General Surgery and Transplantation Surgery, University Hospital Duisburg-Essen, D-45122, Germany
| | - Ying Wu
- Department of Biostatistics, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080, China
| | - Liansuo Zhou
- Department of General Surgery, The First Affiliated Hospital, Xian Medical College, Xian 710061, China
| | - Jinyun He
- Department of General Surgery, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080, China
| | - Chonghua Yang
- Department of General Surgery, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080, China
| | - Peng Zhang
- Department of General Surgery, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080, China
| | - Ronglin Hu
- Department of General Surgery, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080, China
| | - Canqiao Luo
- Deparment of Pathology, Sun Yat-Sen University School of Medicine, Guangzhou 510080, China
| | - Jun Du
- Department of Molecular Biology, Sun Yat-Sen University School of Pharmacy, Guangzhou 510080, China
| | - Jian Fu
- Department of General Surgery and Transplantation Surgery, University Hospital Duisburg-Essen, D-45122, Germany
| | - Jinsen Shi
- Department of Hepatobiliary Surgery, The First Affiliated Hospital, Xian Jiaotong University, Xian 710061, China
| | - Rui He
- Department of General Surgery, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080, China
| | - Dongming Li
- Department of General Surgery, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510080, China
| | - Wang Jun
- Department of Anatomy, Shenzhen University School of Medicine, Shenzhen 518060, China
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20
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Liu S, Lu G, Ali S, Liu W, Zheng L, Dai H, Li H, Xu H, Hua Y, Zhou Y, Ortega J, Li GM, Kunkel TA, Shen B. Okazaki fragment maturation involves α-segment error editing by the mammalian FEN1/MutSα functional complex. EMBO J 2015; 34:1829-43. [PMID: 25921062 DOI: 10.15252/embj.201489865] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 04/14/2015] [Indexed: 11/09/2022] Open
Abstract
During nuclear DNA replication, proofreading-deficient DNA polymerase α (Pol α) initiates Okazaki fragment synthesis with lower fidelity than bulk replication by proofreading-proficient Pol δ or Pol ε. Here, we provide evidence that the exonuclease activity of mammalian flap endonuclease (FEN1) excises Pol α replication errors in a MutSα-dependent, MutLα-independent mismatch repair process we call Pol α-segment error editing (AEE). We show that MSH2 interacts with FEN1 and facilitates its nuclease activity to remove mismatches near the 5' ends of DNA substrates. Mouse cells and mice encoding FEN1 mutations display AEE deficiency, a strong mutator phenotype, enhanced cellular transformation, and increased cancer susceptibility. The results identify a novel role for FEN1 in a specialized mismatch repair pathway and a new cancer etiological mechanism.
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Affiliation(s)
- Songbai Liu
- Colleges of Life Sciences and Agriculture and Biotechnology, Zhejiang University, Hangzhou Zhejiang, China Departments of Radiation Biology and Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, USA
| | - Guojun Lu
- Departments of Radiation Biology and Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, USA
| | - Shafat Ali
- Departments of Radiation Biology and Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, USA
| | - Wenpeng Liu
- Colleges of Life Sciences and Agriculture and Biotechnology, Zhejiang University, Hangzhou Zhejiang, China Departments of Radiation Biology and Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, USA
| | - Li Zheng
- Departments of Radiation Biology and Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, USA
| | - Huifang Dai
- Departments of Radiation Biology and Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, USA
| | - Hongzhi Li
- Departments of Radiation Biology and Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, USA
| | - Hong Xu
- Colleges of Life Sciences and Agriculture and Biotechnology, Zhejiang University, Hangzhou Zhejiang, China
| | - Yuejin Hua
- Colleges of Life Sciences and Agriculture and Biotechnology, Zhejiang University, Hangzhou Zhejiang, China
| | - Yajing Zhou
- Institute of Life Sciences, Jiangsu University, Zhen Jiang Jiangsu, China
| | - Janice Ortega
- Graduate Center for Toxicology, Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Guo-Min Li
- Graduate Center for Toxicology, Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Thomas A Kunkel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC, USA
| | - Binghui Shen
- Departments of Radiation Biology and Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA, USA
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21
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Baple EL, Chambers H, Cross HE, Fawcett H, Nakazawa Y, Chioza BA, Harlalka GV, Mansour S, Sreekantan-Nair A, Patton MA, Muggenthaler M, Rich P, Wagner K, Coblentz R, Stein CK, Last JI, Taylor AMR, Jackson AP, Ogi T, Lehmann AR, Green CM, Crosby AH. Hypomorphic PCNA mutation underlies a human DNA repair disorder. J Clin Invest 2014; 124:3137-46. [PMID: 24911150 PMCID: PMC4071375 DOI: 10.1172/jci74593] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 04/17/2014] [Indexed: 11/17/2022] Open
Abstract
Numerous human disorders, including Cockayne syndrome, UV-sensitive syndrome, xeroderma pigmentosum, and trichothiodystrophy, result from the mutation of genes encoding molecules important for nucleotide excision repair. Here, we describe a syndrome in which the cardinal clinical features include short stature, hearing loss, premature aging, telangiectasia, neurodegeneration, and photosensitivity, resulting from a homozygous missense (p.Ser228Ile) sequence alteration of the proliferating cell nuclear antigen (PCNA). PCNA is a highly conserved sliding clamp protein essential for DNA replication and repair. Due to this fundamental role, mutations in PCNA that profoundly impair protein function would be incompatible with life. Interestingly, while the p.Ser228Ile alteration appeared to have no effect on protein levels or DNA replication, patient cells exhibited marked abnormalities in response to UV irradiation, displaying substantial reductions in both UV survival and RNA synthesis recovery. The p.Ser228Ile change also profoundly altered PCNA's interaction with Flap endonuclease 1 and DNA Ligase 1, DNA metabolism enzymes. Together, our findings detail a mutation of PCNA in humans associated with a neurodegenerative phenotype, displaying clinical and molecular features common to other DNA repair disorders, which we showed to be attributable to a hypomorphic amino acid alteration.
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Affiliation(s)
- Emma L. Baple
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Helen Chambers
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Harold E. Cross
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Heather Fawcett
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Yuka Nakazawa
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Barry A. Chioza
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Gaurav V. Harlalka
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Sahar Mansour
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Ajith Sreekantan-Nair
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Michael A. Patton
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Martina Muggenthaler
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Phillip Rich
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Karin Wagner
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Roselyn Coblentz
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Constance K. Stein
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - James I. Last
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - A. Malcolm R. Taylor
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Andrew P. Jackson
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Tomoo Ogi
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Alan R. Lehmann
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Catherine M. Green
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Andrew H. Crosby
- Medical Research, RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom. Department of Zoology, University of Cambridge, Cambridge, United Kingdom. Department of Ophthalmology, University of Arizona College of Medicine, Tucson, Arizona, USA. Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton, United Kingdom. Nagasaki University Research Centre for Genomic Instability and Carcinogenesis (NRGIC), Nagasaki, Japan. Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan. SW Thames Regional Genetics Service, St. George’s Healthcare NHS Trust, London, United Kingdom. Department of Neuroradiology, St. George’s Hospital, London, United Kingdom. Windows of Hope Genetic Study, Walnut Creek, Ohio, USA. SUNY Upstate Medical University, Syracuse, New York, USA. School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom. MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom. Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
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22
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The cutting edges in DNA repair, licensing, and fidelity: DNA and RNA repair nucleases sculpt DNA to measure twice, cut once. DNA Repair (Amst) 2014; 19:95-107. [PMID: 24754999 DOI: 10.1016/j.dnarep.2014.03.022] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To avoid genome instability, DNA repair nucleases must precisely target the correct damaged substrate before they are licensed to incise. Damage identification is a challenge for all DNA damage response proteins, but especially for nucleases that cut the DNA and necessarily create a cleaved DNA repair intermediate, likely more toxic than the initial damage. How do these enzymes achieve exquisite specificity without specific sequence recognition or, in some cases, without a non-canonical DNA nucleotide? Combined structural, biochemical, and biological analyses of repair nucleases are revealing their molecular tools for damage verification and safeguarding against inadvertent incision. Surprisingly, these enzymes also often act on RNA, which deserves more attention. Here, we review protein-DNA structures for nucleases involved in replication, base excision repair, mismatch repair, double strand break repair (DSBR), and telomere maintenance: apurinic/apyrimidinic endonuclease 1 (APE1), Endonuclease IV (Nfo), tyrosyl DNA phosphodiesterase (TDP2), UV Damage endonuclease (UVDE), very short patch repair endonuclease (Vsr), Endonuclease V (Nfi), Flap endonuclease 1 (FEN1), exonuclease 1 (Exo1), RNase T and Meiotic recombination 11 (Mre11). DNA and RNA structure-sensing nucleases are essential to life with roles in DNA replication, repair, and transcription. Increasingly these enzymes are employed as advanced tools for synthetic biology and as targets for cancer prognosis and interventions. Currently their structural biology is most fully illuminated for DNA repair, which is also essential to life. How DNA repair enzymes maintain genome fidelity is one of the DNA double helix secrets missed by James Watson and Francis Crick, that is only now being illuminated though structural biology and mutational analyses. Structures reveal motifs for repair nucleases and mechanisms whereby these enzymes follow the old carpenter adage: measure twice, cut once. Furthermore, to measure twice these nucleases act as molecular level transformers that typically reshape the DNA and sometimes themselves to achieve extraordinary specificity and efficiency.
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23
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Chung L, Onyango D, Guo Z, Jia P, Dai H, Liu S, Zhou M, Lin W, Pang I, Li H, Yuan YC, Huang Q, Zheng L, Lopes J, Nicolas A, Chai W, Raz D, Reckamp KL, Shen B. The FEN1 E359K germline mutation disrupts the FEN1-WRN interaction and FEN1 GEN activity, causing aneuploidy-associated cancers. Oncogene 2014; 34:902-11. [PMID: 24608430 PMCID: PMC4160428 DOI: 10.1038/onc.2014.19] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 11/18/2013] [Accepted: 12/20/2013] [Indexed: 02/02/2023]
Abstract
Polymorphisms and somatic mutations in Flap Endonuclease 1 (FEN1), an essential enzyme involved in DNA replication and repair, can lead to functional deficiencies of the FEN1 protein and a predisposition to cancer. We identified a FEN1 germline mutation which changed residue E359 to K in a patient whose family had a history of breast cancer. We determined that the E359K mutation, which is in the protein-protein domain of FEN1, abolished the interaction of FEN1 with Werner Syndrome protein (WRN), an interaction which is critical for resolving stalled DNA replication forks. Furthermore, although the flap endonuclease activity of FEN1 E359K was unaffected, it failed to resolve bubble structures, which requires the FEN1 gap dependent endonuclease (GEN) activity. To determine the etiological significance of E359K, we established a mouse model containing this mutation. E359K mouse embryonic fibroblasts (MEF) were more sensitive to DNA cross-linking agents that cause replication forks to stall. Cytological analysis suggested that the FEN1-WRN interaction was also required to for telomere stability; mutant cell lines had fragile telomeres, increased numbers of spontaneous chromosomal anomalies and higher frequencies of transformation. Moreover, the incidence of cancer was significantly higher in mice homozygous for FEN1 E359K than in wild-type mice, suggesting that the FEN1 E359K mutation is oncogenic.
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Affiliation(s)
- L Chung
- Department of Radiation Biology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - D Onyango
- Department of Radiation Biology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - Z Guo
- 1] Department of Radiation Biology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA [2] Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - P Jia
- WWAMI Medical Education Program, School of Molecular Biosciences, Washington State University, Spokane, WA, USA
| | - H Dai
- Department of Radiation Biology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - S Liu
- 1] Department of Radiation Biology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA [2] College of Life Science, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - M Zhou
- Department of Radiation Biology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - W Lin
- Department of Radiation Biology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - I Pang
- Department of Radiation Biology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - H Li
- Department of Molecular Medicine, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - Y-C Yuan
- Department of Molecular Medicine, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - Q Huang
- Department of Pathology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - L Zheng
- Department of Radiation Biology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - J Lopes
- 1] Section de Recherche, Institut Curie, CNRS UMR3244, Paris, France [2] Muséum National d'Histoire Naturelle, USM 503, INSERM U565, UMR7196, Paris, France
| | - A Nicolas
- Section de Recherche, Institut Curie, CNRS UMR3244, Paris, France
| | - W Chai
- WWAMI Medical Education Program, School of Molecular Biosciences, Washington State University, Spokane, WA, USA
| | - D Raz
- Department of Surgery, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - K L Reckamp
- Department of Medical Oncology and Therapeutics Research, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
| | - B Shen
- Department of Radiation Biology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, USA
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24
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Craggs TD, Hutton RD, Brenlla A, White MF, Penedo JC. Single-molecule characterization of Fen1 and Fen1/PCNA complexes acting on flap substrates. Nucleic Acids Res 2014; 42:1857-72. [PMID: 24234453 PMCID: PMC3919604 DOI: 10.1093/nar/gkt1116] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 10/21/2013] [Accepted: 10/22/2013] [Indexed: 11/21/2022] Open
Abstract
Flap endonuclease 1 (Fen1) is a highly conserved structure-specific nuclease that catalyses a specific incision to remove 5' flaps in double-stranded DNA substrates. Fen1 plays an essential role in key cellular processes, such as DNA replication and repair, and mutations that compromise Fen1 expression levels or activity have severe health implications in humans. The nuclease activity of Fen1 and other FEN family members can be stimulated by processivity clamps such as proliferating cell nuclear antigen (PCNA); however, the exact mechanism of PCNA activation is currently unknown. Here, we have used a combination of ensemble and single-molecule Förster resonance energy transfer together with protein-induced fluorescence enhancement to uncouple and investigate the substrate recognition and catalytic steps of Fen1 and Fen1/PCNA complexes. We propose a model in which upon Fen1 binding, a highly dynamic substrate is bent and locked into an open flap conformation where specific Fen1/DNA interactions can be established. PCNA enhances Fen1 recognition of the DNA substrate by further promoting the open flap conformation in a step that may involve facilitated threading of the 5' ssDNA flap. Merging our data with existing crystallographic and molecular dynamics simulations we provide a solution-based model for the Fen1/PCNA/DNA ternary complex.
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Affiliation(s)
- Timothy D. Craggs
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife, KY16 9SS, UK and Biomedical Sciences Research Complex, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - Richard D. Hutton
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife, KY16 9SS, UK and Biomedical Sciences Research Complex, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - Alfonso Brenlla
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife, KY16 9SS, UK and Biomedical Sciences Research Complex, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - Malcolm F. White
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife, KY16 9SS, UK and Biomedical Sciences Research Complex, University of St Andrews, St Andrews, Fife KY16 9SS, UK
| | - J. Carlos Penedo
- SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, Fife, KY16 9SS, UK and Biomedical Sciences Research Complex, University of St Andrews, St Andrews, Fife KY16 9SS, UK
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25
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Lan L, Nakajima S, Wei L, Sun L, Hsieh CL, Sobol RW, Bruchez M, Van Houten B, Yasui A, Levine AS. Novel method for site-specific induction of oxidative DNA damage reveals differences in recruitment of repair proteins to heterochromatin and euchromatin. Nucleic Acids Res 2013; 42:2330-45. [PMID: 24293652 PMCID: PMC3936713 DOI: 10.1093/nar/gkt1233] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Reactive oxygen species (ROS)-induced DNA damage is repaired by the base excision repair pathway. However, the effect of chromatin structure on BER protein recruitment to DNA damage sites in living cells is poorly understood. To address this problem, we developed a method to specifically produce ROS-induced DNA damage by fusing KillerRed (KR), a light-stimulated ROS-inducer, to a tet-repressor (tetR-KR) or a transcription activator (TA-KR). TetR-KR or TA-KR, bound to a TRE cassette (∼90 kb) integrated at a defined genomic locus in U2OS cells, was used to induce ROS damage in hetero- or euchromatin, respectively. We found that DNA glycosylases were efficiently recruited to DNA damage in heterochromatin, as well as in euchromatin. PARP1 was recruited to DNA damage within condensed chromatin more efficiently than in active chromatin. In contrast, recruitment of FEN1 was highly enriched at sites of DNA damage within active chromatin in a PCNA- and transcription activation-dependent manner. These results indicate that oxidative DNA damage is differentially processed within hetero or euchromatin.
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Affiliation(s)
- Li Lan
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, 5117 Centre Avenue, Pittsburgh, PA 15213, USA, School of Medicine, Tsinghua University, No.1 Tsinghua Yuan, Haidian District, Beijing 100084, People's Republic of China, Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA, Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15213, USA, Department of Chemistry and Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA and Division of Dynamic Proteome, Institute of Development, Aging, and Cancer, Tohoku University, Seiryomachi 4-1, Sendai 980-8575, Japan
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26
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Hibi D, Kijima A, Kuroda K, Suzuki Y, Ishii Y, Jin M, Nakajima M, Sugita-Konishi Y, Yanai T, Nohmi T, Nishikawa A, Umemura T. Molecular mechanisms underlying ochratoxin A-induced genotoxicity: global gene expression analysis suggests induction of DNA double-strand breaks and cell cycle progression. J Toxicol Sci 2013; 38:57-69. [PMID: 23358140 DOI: 10.2131/jts.38.57] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Ochratoxin A (OTA) is a renal carcinogen primarily affecting the S3 segment of proximal tubules in rodents. In our previous study, we reported that OTA induces reporter gene mutations, primarily deletion mutations, in the renal outer medulla (OM), specifically in the S3 segment. In the present study, to identify genes involved in OTA-induced genotoxicity, we conducted a comparative analysis of global gene expression in the renal cortex (COR) and OM of kidneys from gpt delta rats administered OTA at a carcinogenic dose for 4 weeks. Genes associated with DNA damage and DNA damage repair, and cell cycle regulation were site-specifically changed in the OM. Interestingly, genes that were deregulated in the OM possessed molecular functions such as DNA double-strand break (DSB) repair (Rad18, Brip1, and Brcc3), cell cycle progression (Cyce1, Ccna2, and Ccnb1), G(2)/M arrest in response to DNA damage (Chek1 and Wee1), and p53-associated factors (Phlda3 and Ccng1). Significant increases in the mRNA levels of many of these genes were observed in the OM using real-time RT-PCR. However, genes related to oxidative stress exhibited no differences in either the number or function of altered genes in both the OM and COR. These results suggested that OTA induced DSB and cell cycle progression at the target site. These events other than oxidative stress could trigger genotoxicity leading to OTA-induced renal tumorigenicity.
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Affiliation(s)
- Daisuke Hibi
- Division of Pathology, National Institute of Health Sciences, Tokyo, Japan
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27
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Hibi D, Kijima A, Suzuki Y, Ishii Y, Jin M, Sugita-Konishi Y, Yanai T, Nishikawa A, Umemura T. Effects of p53 knockout on ochratoxin A-induced genotoxicity in p53-deficient gpt delta mice. Toxicology 2013; 304:92-9. [DOI: 10.1016/j.tox.2012.12.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 12/04/2012] [Accepted: 12/10/2012] [Indexed: 01/31/2023]
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28
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van Pel DM, Barrett IJ, Shimizu Y, Sajesh BV, Guppy BJ, Pfeifer T, McManus KJ, Hieter P. An evolutionarily conserved synthetic lethal interaction network identifies FEN1 as a broad-spectrum target for anticancer therapeutic development. PLoS Genet 2013; 9:e1003254. [PMID: 23382697 PMCID: PMC3561056 DOI: 10.1371/journal.pgen.1003254] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 12/04/2012] [Indexed: 12/22/2022] Open
Abstract
Harnessing genetic differences between cancerous and noncancerous cells offers a strategy for the development of new therapies. Extrapolating from yeast genetic interaction data, we used cultured human cells and siRNA to construct and evaluate a synthetic lethal interaction network comprised of chromosome instability (CIN) genes that are frequently mutated in colorectal cancer. A small number of genes in this network were found to have synthetic lethal interactions with a large number of cancer CIN genes; these genes are thus attractive targets for anticancer therapeutic development. The protein product of one highly connected gene, the flap endonuclease FEN1, was used as a target for small-molecule inhibitor screening using a newly developed fluorescence-based assay for enzyme activity. Thirteen initial hits identified through in vitro biochemical screening were tested in cells, and it was found that two compounds could selectively inhibit the proliferation of cultured cancer cells carrying inactivating mutations in CDC4, a gene frequently mutated in a variety of cancers. Inhibition of flap endonuclease activity was also found to recapitulate a genetic interaction between FEN1 and MRE11A, another gene frequently mutated in colorectal cancers, and to lead to increased endogenous DNA damage. These chemical-genetic interactions in mammalian cells validate evolutionarily conserved synthetic lethal interactions and demonstrate that a cross-species candidate gene approach is successful in identifying small-molecule inhibitors that prove effective in a cell-based cancer model.
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Affiliation(s)
- Derek M. van Pel
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Irene J. Barrett
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
| | - Yoko Shimizu
- Department of Screening, Centre for Drug Research and Development, Vancouver, Canada
| | - Babu V. Sajesh
- Department of Screening, Centre for Drug Research and Development, Vancouver, Canada
| | - Brent J. Guppy
- Department of Screening, Centre for Drug Research and Development, Vancouver, Canada
| | - Tom Pfeifer
- Department of Screening, Centre for Drug Research and Development, Vancouver, Canada
| | - Kirk J. McManus
- Manitoba Institute of Cell Biology, Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Canada
| | - Philip Hieter
- Michael Smith Laboratories, University of British Columbia, Vancouver, Canada
- * E-mail:
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29
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Mason PA, Cox LS. The role of DNA exonucleases in protecting genome stability and their impact on ageing. AGE (DORDRECHT, NETHERLANDS) 2012; 34:1317-1340. [PMID: 21948156 PMCID: PMC3528374 DOI: 10.1007/s11357-011-9306-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 08/19/2011] [Indexed: 05/30/2023]
Abstract
Exonucleases are key enzymes involved in many aspects of cellular metabolism and maintenance and are essential to genome stability, acting to cleave DNA from free ends. Exonucleases can act as proof-readers during DNA polymerisation in DNA replication, to remove unusual DNA structures that arise from problems with DNA replication fork progression, and they can be directly involved in repairing damaged DNA. Several exonucleases have been recently discovered, with potentially critical roles in genome stability and ageing. Here we discuss how both intrinsic and extrinsic exonuclease activities contribute to the fidelity of DNA polymerases in DNA replication. The action of exonucleases in processing DNA intermediates during normal and aberrant DNA replication is then assessed, as is the importance of exonucleases in repair of double-strand breaks and interstrand crosslinks. Finally we examine how exonucleases are involved in maintenance of mitochondrial genome stability. Throughout the review, we assess how nuclease mutation or loss predisposes to a range of clinical diseases and particularly ageing.
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Affiliation(s)
- Penelope A. Mason
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Lynne S. Cox
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
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30
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Yang H, Liu C, Jamsen J, Wu Z, Wang Y, Chen J, Zheng L, Shen B. The DNase domain-containing protein TATDN1 plays an important role in chromosomal segregation and cell cycle progression during zebrafish eye development. Cell Cycle 2012. [PMID: 23187801 DOI: 10.4161/cc.22886] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The DNase domain-containing protein TATDN1 is a conserved nuclease in both prokaryotes and eukaryotes. It was previously implicated to play a role in apoptotic DNA fragmentation in yeast and C. elegans. However, its biological function in higher organisms, such as vertebrates, is unknown. Here, we report that zebrafish TATDN1 (zTATDN1) possesses a novel endonuclease activity, which first makes a nick at the DNA duplex and subsequently converts the nick into a DNA double-strand break in vitro. This biochemical property allows zTATDN1 to catalyze decatenation of catenated kinetoplast DNA to produce separated linear DNA in vitro. We further determine that zTATDN1 is predominantly expressed in eye cells during embryonic development. Knockdown of TATDN1 in zebrafish embryos results in an abnormal cell cycle progression, formation of polyploidy and aberrant chromatin structures. Consequently, the TATDN1-deficient morphants have disordered eye cell layers and significantly smaller eyes compared with the WT control. Altogether, our current studies suggest that zTATDN1 plays an important role in chromosome segregation and eye development in zebrafish.
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Affiliation(s)
- Hui Yang
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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31
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Zheng L, Dai H, Zhou M, Li X, Liu C, Guo Z, Wu X, Wu J, Wang C, Zhong J, Huang Q, Garcia-Aguilar J, Pfeifer GP, Shen B. Polyploid cells rewire DNA damage response networks to overcome replication stress-induced barriers for tumour progression. Nat Commun 2012; 3:815. [PMID: 22569363 PMCID: PMC3517178 DOI: 10.1038/ncomms1825] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 04/05/2012] [Indexed: 11/09/2022] Open
Abstract
Mutations in genes involved in DNA replication, such as flap endonuclease 1 (FEN1), can cause single-stranded DNA breaks (SSBs) and subsequent collapse of DNA replication forks leading to DNA replication stresses. Persistent replication stresses normally induce p53-mediated senescence or apoptosis to prevent tumour progression. It is unclear how some mutant cells can overcome persistent replication stresses and bypass the p53-mediated pathways to develop malignancy. Here we show that polyploidy, which is often observed in human cancers, leads to overexpression of BRCA1, p19arf and other DNA repair genes in FEN1 mutant cells. This overexpression triggers SSB repair and non-homologous end-joining pathways to increase DNA repair activity, but at the cost of frequent chromosomal translocations. Meanwhile, DNA methylation silences p53 target genes to bypass the p53-mediated senescence and apoptosis. These molecular changes rewire DNA damage response and repair gene networks in polyploid tumour cells, enabling them to escape replication stress-induced senescence barriers.
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Affiliation(s)
- Li Zheng
- Department of Cancer Biology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010
| | - Huifang Dai
- Department of Cancer Biology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010
| | - Mian Zhou
- Department of Cancer Biology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010
| | - Xiaojin Li
- Department of Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010
| | - Changwei Liu
- Department of Cancer Biology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Zhigang Guo
- Department of Cancer Biology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010
| | - Xiwei Wu
- Department of Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010
| | - Jun Wu
- Department of Clinical and Molecular Pharmacology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010
| | - Charles Wang
- Department of Molecular Medicine, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010
| | - John Zhong
- Department of Pathology, 1501 San Pablo St., ZNI 529, University of Southern California, Los Angeles, CA 90033
| | - Qin Huang
- Department of Pathology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010
| | - Julio Garcia-Aguilar
- Department of Surgery, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010
| | - Gerd P. Pfeifer
- Department of Cancer Biology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010
| | - Binghui Shen
- Department of Cancer Biology, City of Hope National Medical Center and Beckman Research Institute, 1500 East Duarte Road, Duarte, CA 91010
- College of Life Sciences, Zhejiang University, Hangzhou, China
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32
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Hegde ML, Izumi T, Mitra S. Oxidized base damage and single-strand break repair in mammalian genomes: role of disordered regions and posttranslational modifications in early enzymes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 110:123-53. [PMID: 22749145 DOI: 10.1016/b978-0-12-387665-2.00006-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Oxidative genome damage induced by reactive oxygen species includes oxidized bases, abasic (AP) sites, and single-strand breaks, all of which are repaired via the evolutionarily conserved base excision repair/single-strand break repair (BER/SSBR) pathway. BER/SSBR in mammalian cells is complex, with preferred and backup sub-pathways, and is linked to genome replication and transcription. The early BER/SSBR enzymes, namely, DNA glycosylases (DGs) and the end-processing proteins such as abasic endonuclease 1 (APE1), form complexes with downstream repair (and other noncanonical) proteins via pairwise interactions. Furthermore, a unique feature of mammalian early BER/SSBR enzymes is the presence of a disordered terminal extension that is absent in their Escherichia coli prototypes. These nonconserved segments usually contain organelle-targeting signals, common interaction interfaces, and sites of posttranslational modifications that may be involved in regulating their repair function including lesion scanning. Finally, the linkage of BER/SSBR deficiency to cancer, aging, and human neurodegenerative diseases, and therapeutic targeting of BER/SSBR are discussed.
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Affiliation(s)
- Muralidhar L Hegde
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
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Finger LD, Atack JM, Tsutakawa S, Classen S, Tainer J, Grasby J, Shen B. The wonders of flap endonucleases: structure, function, mechanism and regulation. Subcell Biochem 2012; 62:301-26. [PMID: 22918592 PMCID: PMC3728657 DOI: 10.1007/978-94-007-4572-8_16] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Processing of Okazaki fragments to complete lagging strand DNA synthesis requires coordination among several proteins. RNA primers and DNA synthesised by DNA polymerase α are displaced by DNA polymerase δ to create bifurcated nucleic acid structures known as 5'-flaps. These 5'-flaps are removed by Flap Endonuclease 1 (FEN), a structure-specific nuclease whose divalent metal ion-dependent phosphodiesterase activity cleaves 5'-flaps with exquisite specificity. FENs are paradigms for the 5' nuclease superfamily, whose members perform a wide variety of roles in nucleic acid metabolism using a similar nuclease core domain that displays common biochemical properties and structural features. A detailed review of FEN structure is undertaken to show how DNA substrate recognition occurs and how FEN achieves cleavage at a single phosphate diester. A proposed double nucleotide unpairing trap (DoNUT) is discussed with regards to FEN and has relevance to the wider 5' nuclease superfamily. The homotrimeric proliferating cell nuclear antigen protein (PCNA) coordinates the actions of DNA polymerase, FEN and DNA ligase by facilitating the hand-off intermediates between each protein during Okazaki fragment maturation to maximise through-put and minimise consequences of intermediates being released into the wider cellular environment. FEN has numerous partner proteins that modulate and control its action during DNA replication and is also controlled by several post-translational modification events, all acting in concert to maintain precise and appropriate cleavage of Okazaki fragment intermediates during DNA replication.
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Affiliation(s)
- L. David Finger
- Department of Chemistry, Centre for Chemical Biology, Krebs Institute, University of Sheffield, Sheffield S3 7HF, UK
| | - John M. Atack
- Department of Chemistry, Centre for Chemical Biology, Krebs Institute, University of Sheffield, Sheffield S3 7HF, UK
| | - Susan Tsutakawa
- Life Sciences Division, Lawrence Berkeley National, Laboratory, Berkeley, CA 94720, USA
| | - Scott Classen
- Physical Biosciences Division, The Scripps Research, Institute, La Jolla, CA 92037, USA
| | - John Tainer
- Life Sciences Division, Lawrence Berkeley, National Laboratory, Berkeley, CA 94720, USA, Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA, Skaggs Institute for Chemical Biology, La Jolla, CA 92037, USA
| | - Jane Grasby
- Department of Chemistry, Centre for Chemical Biology, Krebs Institute, University of Sheffield, Sheffield S3 7HF, UK
| | - Binghui Shen
- Division of Radiation Biology, City of Hope National Medical Center and Beckman Research Institute, Duarte, CA 91010, USA, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
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High risk of benzo[α]pyrene-induced lung cancer in E160D FEN1 mutant mice. Mutat Res 2011; 731:85-91. [PMID: 22155171 DOI: 10.1016/j.mrfmmm.2011.11.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 11/18/2011] [Accepted: 11/25/2011] [Indexed: 11/20/2022]
Abstract
Flap endonuclease 1 (FEN1), a member of the Rad2 nuclease family, possesses 5' flap endonuclease (FEN), 5' exonuclease (EXO), and gap-endonuclease (GEN) activities. The multiple, structure-specific nuclease activities of FEN1 allow it to process different intermediate DNA structures during DNA replication and repair. We previously identified a group of FEN1 mutations and single nucleotide polymorphisms that impair FEN1's EXO and GEN activities in human cancer patients. We also established a mouse model carrying the E160D FEN1 mutation, which mimics the mutations seen in humans. FEN1 mutant mice developed spontaneous lung cancer at high frequency at their late life stages. An important unanswered question is whether individuals carrying such FEN1 mutation are more susceptible to tobacco smoke and have an earlier onset of lung cancer. Here, we report our study on E160D mutant mice exposed to benzo[α]pyrene (B[α]P), a major DNA damaging compound found in tobacco smoke. We demonstrate that FEN1 employs its GEN activity to cleave DNA bubble substrates with BP-induced lesions, but the E160D FEN1 mutation abolishes such activity. As a consequence, Mouse cells carrying the E160D mutation display defects in the repair of B[α]P adducts and accumulate DNA double-stranded breaks and chromosomal aberrations upon treatments with B[α]P. Furthermore, more E160D mice than WT mice have an early onset of B[α]P-induced lung adenocarcinoma. All together, our current study suggests that individuals carrying the GEN-deficient FEN1 mutations have high risk to develop lung cancer upon exposure to B[α]P-containing agents such as tobacco smoke.
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