1
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McMahon A, Zhao J, Yan S. Ubiquitin-mediated regulation of APE2 protein abundance. J Biol Chem 2024; 300:107337. [PMID: 38705397 PMCID: PMC11157268 DOI: 10.1016/j.jbc.2024.107337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 04/12/2024] [Accepted: 04/24/2024] [Indexed: 05/07/2024] Open
Abstract
APE2 plays important roles in the maintenance of genomic and epigenomic stability including DNA repair and DNA damage response. Accumulating evidence has suggested that APE2 is upregulated in multiple cancers at the protein and mRNA levels and that APE2 upregulation is correlative with higher and lower overall survival of cancer patients depending on tumor type. However, it remains unknown how APE2 protein abundance is maintained and regulated in cells. Here, we provide the first evidence of APE2 regulation via the posttranslational modification ubiquitin. APE2 is poly-ubiquitinated via K48-linked chains and degraded via the ubiquitin-proteasome system where K371 is the key residue within APE2 responsible for its ubiquitination and degradation. We further characterize MKRN3 as the E3 ubiquitin ligase for APE2 ubiquitination in cells and in vitro. In summary, this study offers the first definition of the APE2 proteostasis network and lays the foundation for future studies pertaining to the posttranslational modification regulation and functions of APE2 in genome integrity and cancer etiology/treatment.
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Affiliation(s)
- Anne McMahon
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA
| | - Jianjun Zhao
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA; School of Data Science, University of North Carolina at Charlotte, Charlotte, North Carolina, USA; Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, Charlotte, North Carolina, USA.
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2
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Hoitsma NM, Norris J, Khoang TH, Kaushik V, Chadda R, Antony E, Hedglin M, Freudenthal BD. Mechanistic insight into AP-endonuclease 1 cleavage of abasic sites at stalled replication fork mimics. Nucleic Acids Res 2023; 51:6738-6753. [PMID: 37264933 PMCID: PMC10359615 DOI: 10.1093/nar/gkad481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 05/13/2023] [Accepted: 05/31/2023] [Indexed: 06/03/2023] Open
Abstract
Many types of damage, including abasic sites, block replicative DNA polymerases causing replication fork uncoupling and generating ssDNA. AP-Endonuclease 1 (APE1) has been shown to cleave abasic sites in ssDNA. Importantly, APE1 cleavage of ssDNA at a replication fork has significant biological implications by generating double strand breaks that could collapse the replication fork. Despite this, the molecular basis and efficiency of APE1 processing abasic sites at replication forks remain elusive. Here, we investigate APE1 cleavage of abasic substrates that mimic APE1 interactions at stalled replication forks or gaps. We determine that APE1 has robust activity on these substrates, like dsDNA, and report rates for cleavage and product release. X-ray structures visualize the APE1 active site, highlighting an analogous mechanism is used to process ssDNA substrates as canonical APE1 activity on dsDNA. However, mutational analysis reveals R177 to be uniquely critical for the APE1 ssDNA cleavage mechanism. Additionally, we investigate the interplay between APE1 and Replication Protein A (RPA), the major ssDNA-binding protein at replication forks, revealing that APE1 can cleave an abasic site while RPA is still bound to the DNA. Together, this work provides molecular level insights into abasic ssDNA processing by APE1, including the presence of RPA.
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Affiliation(s)
- Nicole M Hoitsma
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Jessica Norris
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Thu H Khoang
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Vikas Kaushik
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Rahul Chadda
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Mark Hedglin
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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3
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Schrader CE, Williams T, Pechhold K, Linehan EK, Tsuchimoto D, Nakabeppu Y. APE2 Promotes AID-Dependent Somatic Hypermutation in Primary B Cell Cultures That Is Suppressed by APE1. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 210:1804-1814. [PMID: 37074207 PMCID: PMC10234595 DOI: 10.4049/jimmunol.2100946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 03/29/2023] [Indexed: 04/20/2023]
Abstract
Somatic hypermutation (SHM) is necessary for Ab diversification and involves error-prone DNA repair of activation-induced cytidine deaminase-induced lesions in germinal center (GC) B cells but can also cause genomic instability. GC B cells express low levels of the DNA repair protein apurinic/apyrimidinic (AP) endonuclease (APE)1 and high levels of its homolog APE2. Reduced SHM in APE2-deficient mice suggests that APE2 promotes SHM, but these GC B cells also exhibit reduced proliferation that could impact mutation frequency. In this study, we test the hypothesis that APE2 promotes and APE1 suppresses SHM. We show how APE1/APE2 expression changes in primary murine spleen B cells during activation, impacting both SHM and class-switch recombination (CSR). High levels of both APE1 and APE2 early after activation promote CSR. However, after 2 d, APE1 levels decrease steadily with each cell division, even with repeated stimulation, whereas APE2 levels increase with each stimulation. When GC-level APE1/APE2 expression was engineered by reducing APE1 genetically (apex1+/-) and overexpressing APE2, bona fide activation-induced cytidine deaminase-dependent VDJH4 intron SHM became detectable in primary B cell cultures. The C terminus of APE2 that interacts with proliferating cell nuclear Ag promotes SHM and CSR, although its ATR-Chk1-interacting Zf-GRF domain is not required. However, APE2 does not increase mutations unless APE1 is reduced. Although APE1 promotes CSR, it suppresses SHM, suggesting that downregulation of APE1 in the GC is required for SHM. Genome-wide expression data compare GC and cultured B cells and new models depict how APE1 and APE2 expression and protein interactions change during B cell activation and affect the balance between accurate and error-prone repair during CSR and SHM.
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Affiliation(s)
- Carol E. Schrader
- Department of Microbiology and Physiological Systems, Program in Immunology and Microbiology, UMassChan Medical School, Worcester, MA 01655
| | - Travis Williams
- Department of Microbiology and Physiological Systems, Program in Immunology and Microbiology, UMassChan Medical School, Worcester, MA 01655
| | - Klaus Pechhold
- Department of Microbiology and Physiological Systems, Program in Immunology and Microbiology, UMassChan Medical School, Worcester, MA 01655
| | - Erin K. Linehan
- Department of Microbiology and Physiological Systems, Program in Immunology and Microbiology, UMassChan Medical School, Worcester, MA 01655
| | - Daisuke Tsuchimoto
- Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yusaku Nakabeppu
- Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
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4
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Liu Z, Jiang M, Chen X, Liu Q, Guo X, Lin C, Guo Y. Female BMI has an effect on oocyte gene expression pattern. Heliyon 2023; 9:e17493. [PMID: 37408896 PMCID: PMC10318509 DOI: 10.1016/j.heliyon.2023.e17493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/08/2023] [Accepted: 06/20/2023] [Indexed: 07/07/2023] Open
Abstract
Purpose To explore the mechanisms by which abnormal female BMI affects oocyte quality, particularly whether it involves the alteration of gene expression patterns and how these patterns may impact clinical outcomes. Methods In Part 1, we performed a retrospective study to compare the clinical outcomes between the female BMI ≥25 kg/m2 and female BMI ≤20 kg/m2 groups. In Part 2, we performed the transcriptome analyses based on the GSE87201 dataset. Results In Part 1, among the clinical outcomes, only the grade 1-2 embryo rate at day 3 of ICSI cycles was significantly different between the two BMI groups; the other outcomes were not. In Part 2, compared with the BMI ≤20 kg/m2 group, the oocyte gene expression pattern of the BMI ≥25 kg/m2 group seemed to result in better oocyte tolerance to exogenous stress, such as intracytoplasmic sperm injection (ICSI). It seemed to explain the result of Part 1 that the BMI ≥25 kg/m2 group had better day-3 embryo quality after ICSI than the BMI ≤20 kg/m2 group. Conclusions Abnormal female BMI affects oocyte quality by altering the gene expression patterns of oocytes. While a female BMI ≥25 kg/m2 is known to have certain detrimental effects on ART, our findings suggest that it can also confer some benefits to oocytes.
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Affiliation(s)
- Zhiren Liu
- Center for Reproductive Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China
- NHC Key Laboratory of Study on Abnormal Gametes and Reproductive Tract (Anhui Medical University), No.81 Meishan Road, Hefei, 230032, Anhui, China
- Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, China
| | - Mingting Jiang
- Fujian Key Laboratory of Translational Research in Cancer and Neurodegenerative Diseases, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian, China
| | - Xingting Chen
- Center for Reproductive Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China
| | - Qicai Liu
- Center for Reproductive Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China
| | - Xinxin Guo
- Center for Reproductive Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China
| | - Chen Lin
- Center for Reproductive Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China
| | - Yujia Guo
- Center for Reproductive Medicine, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China
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5
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Fleury H, MacEachern MK, Stiefel CM, Anand R, Sempeck C, Nebenfuehr B, Maurer-Alcalá K, Ball K, Proctor B, Belan O, Taylor E, Ortega R, Dodd B, Weatherly L, Dansoko D, Leung JW, Boulton SJ, Arnoult N. The APE2 nuclease is essential for DNA double-strand break repair by microhomology-mediated end joining. Mol Cell 2023; 83:1429-1445.e8. [PMID: 37044098 PMCID: PMC10164096 DOI: 10.1016/j.molcel.2023.03.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 01/18/2023] [Accepted: 03/16/2023] [Indexed: 04/14/2023]
Abstract
Microhomology-mediated end joining (MMEJ) is an intrinsically mutagenic pathway of DNA double-strand break (DSB) repair essential for proliferation of homologous recombination (HR)-deficient tumors. Although targeting MMEJ has emerged as a powerful strategy to eliminate HR-deficient (HRD) cancers, this is limited by an incomplete understanding of the mechanism and factors required for MMEJ repair. Here, we identify the APE2 nuclease as an MMEJ effector. We show that loss of APE2 inhibits MMEJ at deprotected telomeres and at intra-chromosomal DSBs and is epistatic with Pol Theta for MMEJ activity. Mechanistically, we demonstrate that APE2 possesses intrinsic flap-cleaving activity, that its MMEJ function in cells depends on its nuclease activity, and further identify an uncharacterized domain required for its recruitment to DSBs. We conclude that this previously unappreciated role of APE2 in MMEJ contributes to the addiction of HRD cells to APE2, which could be exploited in the treatment of cancer.
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Affiliation(s)
- Hubert Fleury
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Myles K MacEachern
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Clara M Stiefel
- Department of Radiation Oncology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Roopesh Anand
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London, UK
| | - Colin Sempeck
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Benjamin Nebenfuehr
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Kelper Maurer-Alcalá
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Kerri Ball
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Bruce Proctor
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Ondrej Belan
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London, UK
| | - Erin Taylor
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Raquel Ortega
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Benjamin Dodd
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Laila Weatherly
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Djelika Dansoko
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Justin W Leung
- Department of Radiation Oncology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Simon J Boulton
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London, UK; Artios Pharma Ltd, Babraham Research Campus, Cambridge CB22 3FH, UK
| | - Nausica Arnoult
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO, USA.
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6
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McMahon A, Zhao J, Yan S. APE2: catalytic function and synthetic lethality draw attention as a cancer therapy target. NAR Cancer 2023; 5:zcad006. [PMID: 36755963 PMCID: PMC9900424 DOI: 10.1093/narcan/zcad006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 02/08/2023] Open
Abstract
AP endonuclease 2 (APE2, APEX2 or APN2) is an emerging critical protein involved in genome and epigenome integrity. Whereas its catalytic function as a nuclease in DNA repair is widely accepted, recent studies have elucidated the function and mechanism of APE2 in the immune response and DNA damage response. Several genome-wide screens have identified APE2 as a synthetic lethal target for deficiencies of BRCA1, BRCA2 or TDP1 in cancer cells. Due to its overexpression in several cancer types, APE2 is proposed as an oncogene and could serve as prognostic marker of overall survival of cancer treatment. However, it remains to be discovered whether and how APE2 catalytic function and synthetic lethality can be modulated and manipulated as a cancer therapy target. In this review, we provide a current understanding of alterations and expression of APE2 in cancer, the function of APE2 in the immune response, and mechanisms of APE2 in ATR/Chk1 DNA damage response. We also summarize the role of APE2 in DNA repair pathways in the removal of heterogenous and complexed 3'-termini and MMEJ. Finally, we provide an updated perspective on how APE2 may be targeted for cancer therapy and future directions of APE2 studies in cancer biology.
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Affiliation(s)
- Anne McMahon
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Jianjun Zhao
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
- School of Data Science, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
- Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
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7
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Wu L, Shukla V, Yadavalli AD, Dinesh RK, Xu D, Rao A, Schatz DG. HMCES protects immunoglobulin genes specifically from deletions during somatic hypermutation. Genes Dev 2022; 36:433-450. [PMID: 35450882 PMCID: PMC9067407 DOI: 10.1101/gad.349438.122] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 03/29/2022] [Indexed: 01/07/2023]
Abstract
Somatic hypermutation (SHM) produces point mutations in immunoglobulin (Ig) genes in B cells when uracils created by the activation-induced deaminase are processed in a mutagenic manner by enzymes of the base excision repair (BER) and mismatch repair (MMR) pathways. Such uracil processing creates DNA strand breaks and is susceptible to the generation of deleterious deletions. Here, we demonstrate that the DNA repair factor HMCES strongly suppresses deletions without significantly affecting other parameters of SHM in mouse and human B cells, thereby facilitating the production of antigen-specific antibodies. The deletion-prone repair pathway suppressed by HMCES operates downstream from the uracil glycosylase UNG and is mediated by the combined action of BER factor APE2 and MMR factors MSH2, MSH6, and EXO1. HMCES's ability to shield against deletions during SHM requires its capacity to form covalent cross-links with abasic sites, in sharp contrast to its DNA end-joining role in class switch recombination but analogous to its genome-stabilizing role during DNA replication. Our findings lead to a novel model for the protection of Ig gene integrity during SHM in which abasic site cross-linking by HMCES intercedes at a critical juncture during processing of vulnerable gapped DNA intermediates by BER and MMR enzymes.
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Affiliation(s)
- Lizhen Wu
- Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Vipul Shukla
- Division of Signaling and Gene Expression, La Jolla Institute for Immunology, La Jolla, California 92037, USA
| | | | - Ravi K Dinesh
- Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Dijin Xu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Anjana Rao
- Division of Signaling and Gene Expression, La Jolla Institute for Immunology, La Jolla, California 92037, USA
- Department of Pharmacology, Moores Cancer Center, University of California at San Diego, La Jolla, California 92093, USA
- Consortium for Regenerative Medicine, La Jolla, California 92037, USA
| | - David G Schatz
- Department of Immunobiology, Yale School of Medicine, New Haven, Connecticut 06520, USA
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8
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Hossain MA, Lin Y, Driscoll G, Li J, McMahon A, Matos J, Zhao H, Tsuchimoto D, Nakabeppu Y, Zhao J, Yan S. APE2 Is a General Regulator of the ATR-Chk1 DNA Damage Response Pathway to Maintain Genome Integrity in Pancreatic Cancer Cells. Front Cell Dev Biol 2021; 9:738502. [PMID: 34796173 PMCID: PMC8593216 DOI: 10.3389/fcell.2021.738502] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 10/14/2021] [Indexed: 12/18/2022] Open
Abstract
The maintenance of genome integrity and fidelity is vital for the proper function and survival of all organisms. Recent studies have revealed that APE2 is required to activate an ATR-Chk1 DNA damage response (DDR) pathway in response to oxidative stress and a defined DNA single-strand break (SSB) in Xenopus laevis egg extracts. However, it remains unclear whether APE2 is a general regulator of the DDR pathway in mammalian cells. Here, we provide evidence using human pancreatic cancer cells that APE2 is essential for ATR DDR pathway activation in response to different stressful conditions including oxidative stress, DNA replication stress, and DNA double-strand breaks. Fluorescence microscopy analysis shows that APE2-knockdown (KD) leads to enhanced γH2AX foci and increased micronuclei formation. In addition, we identified a small molecule compound Celastrol as an APE2 inhibitor that specifically compromises the binding of APE2 but not RPA to ssDNA and 3′-5′ exonuclease activity of APE2 but not APE1. The impairment of ATR-Chk1 DDR pathway by Celastrol in Xenopus egg extracts and human pancreatic cancer cells highlights the physiological significance of Celastrol in the regulation of APE2 functionalities in genome integrity. Notably, cell viability assays demonstrate that APE2-KD or Celastrol sensitizes pancreatic cancer cells to chemotherapy drugs. Overall, we propose APE2 as a general regulator for the DDR pathway in genome integrity maintenance.
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Affiliation(s)
- Md Akram Hossain
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, United States
| | - Yunfeng Lin
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, United States
| | - Garrett Driscoll
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, United States
| | - Jia Li
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, United States
| | - Anne McMahon
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, United States
| | - Joshua Matos
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, United States
| | - Haichao Zhao
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, United States
| | - Daisuke Tsuchimoto
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Yusaku Nakabeppu
- Division of Neurofunctional Genomics, Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Jianjun Zhao
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, United States
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9
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Housh K, Jha JS, Yang Z, Haldar T, Johnson KM, Yin J, Wang Y, Gates KS. Formation and Repair of an Interstrand DNA Cross-Link Arising from a Common Endogenous Lesion. J Am Chem Soc 2021; 143:15344-15357. [PMID: 34516735 DOI: 10.1021/jacs.1c06926] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Interstrand DNA cross-links (ICLs) are cytotoxic because they block the strand separation required for read-out and replication of the genetic information in duplex DNA. The unavoidable formation of ICLs in cellular DNA may contribute to aging, neurodegeneration, and cancer. Here, we describe the formation and properties of a structurally complex ICL derived from an apurinic/apyrimidinic (AP) site, which is one of the most common endogenous lesions in cellular DNA. The results characterize a cross-link arising from aza-Michael addition of the N2-amino group of a guanine residue to the electrophilic sugar remnant generated by spermine-mediated strand cleavage at an AP site in duplex DNA. An α,β-unsaturated iminium ion is the critical intermediate involved in ICL formation. Studies employing the bacteriophage φ29 polymerase provided evidence that this ICL can block critical DNA transactions that require strand separation. The results of biochemical studies suggest that this complex strand break/ICL might be repaired by a simple mechanism in which the 3'-exonuclease action of the enzyme apurinic/apyrimidinic endonuclease (APE1) unhooks the cross-link to initiate repair via the single-strand break repair pathway.
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Affiliation(s)
- Kurt Housh
- University of Missouri Department of Chemistry 125 Chemistry Building Columbia, Missouri 65211, United States
| | - Jay S Jha
- University of Missouri Department of Chemistry 125 Chemistry Building Columbia, Missouri 65211, United States
| | - Zhiyu Yang
- University of Missouri Department of Chemistry 125 Chemistry Building Columbia, Missouri 65211, United States
| | - Tuhin Haldar
- University of Missouri Department of Chemistry 125 Chemistry Building Columbia, Missouri 65211, United States
| | - Kevin M Johnson
- University of Missouri Department of Chemistry 125 Chemistry Building Columbia, Missouri 65211, United States
| | - Jiekai Yin
- Department of Chemistry University of California-Riverside Riverside, California 92521-0403, United States
| | - Yinsheng Wang
- Department of Chemistry University of California-Riverside Riverside, California 92521-0403, United States
| | - Kent S Gates
- University of Missouri Department of Chemistry 125 Chemistry Building Columbia, Missouri 65211, United States.,University of Missouri Department of Biochemistry 125 Chemistry Building Columbia, Missouri 65211, United States
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10
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Apurinic/Apyrimidinic Endonuclease 2 (APE2): An ancillary enzyme for contextual base excision repair mechanisms to preserve genome stability. Biochimie 2021; 190:70-90. [PMID: 34302888 DOI: 10.1016/j.biochi.2021.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/29/2021] [Accepted: 07/19/2021] [Indexed: 01/03/2023]
Abstract
The genome of living organisms frequently undergoes various types of modifications which are recognized and repaired by the relevant repair mechanisms. These repair pathways are increasingly being deciphered to understand the mechanisms. Base excision repair (BER) is indispensable to maintain genome stability. One of the enigmatic repair proteins of BER, Apurinic/Apyrimidinic Endonuclease 2 (APE2), like APE1, is truly multifunctional and demonstrates the independent and non-redundant function in maintaining the genome integrity. APE2 is involved in ATR-Chk1 mediated DNA damage response. It also resolves topoisomerase1 mediated cleavage complex intermediate which is formed while repairing misincorporated ribonucleotides in the absence of functional RNase H2 mediated excision repair pathway. BER participates in the demethylation pathway and the role of Arabidopsis thaliana APE2 is demonstrated in this process. Moreover, APE2 is synthetically lethal to BRCA1, BRCA2, and RNase H2, and its homolog, APE1 fails to complement the function. Hence, the role of APE2 is not just an alternate to the repair mechanisms but has implications in diverse functional pathways related to the maintenance of genome integrity. This review analyses genomic features of APE2 and delineates its enzyme function as error-prone as well as efficient and accurate repair protein based on the studies on mammalian or its homolog proteins from model systems such as Arabidopsis thaliana, Schizosaccharomyces pombe, Trypanosoma curzi, Xenopus laevis, Danio rerio, Mus musculus, and Homo sapiens.
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11
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Altered APE1 activity on abasic ribonucleotides is mediated by changes in the nucleoside sugar pucker. Comput Struct Biotechnol J 2021; 19:3293-3302. [PMID: 34188778 PMCID: PMC8207216 DOI: 10.1016/j.csbj.2021.05.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 05/14/2021] [Accepted: 05/20/2021] [Indexed: 12/18/2022] Open
Abstract
Ribonucleotides (rNTPs) are predicted to be incorporated into the genome at a rate of up to 3 million times per cell division, making rNTPs the most common non-standard nucleotide in the human genome. Typically, misinserted ribonucleotides are repaired by the ribonucleotide excision repair (RER) pathway, which is initiated by RNase H2 cleavage. However, rNTPs are susceptible to spontaneous depurination generating abasic ribonucleotides (rAPs), which are unable to be processed by RNase H2. Additionally, rAPs have been found in nascent RNA and coupled to R-loops. Recent work identified that base excision repair (BER) protein AP-Endonuclease 1 (APE1) is responsible for the initial processing of rAPs embedded in DNA and in R-loops. APE1 is a well characterized AP endonuclease that cleaves 5' of abasic sites, but its ability to cleave at rAPs remains poorly understood. Here, we utilize enzyme kinetics, X-ray crystallography, and molecular dynamics simulations to provide insight into rAP processing by APE1. Enzyme kinetics were used to determine pre-steady-state rates of APE1 cleavage on DNA substrates containing rAP, revealing a decrease in activity compared to cleavage at a canonical deoxy-AP substrate. Using X-ray crystallography, we identified novel contacts between the rAP and the APE1 active site. We demonstrate that the rAP sugar pucker is accommodated in the active site in a C3'-endo conformation, influencing its position and contributing to a decrease in activity compared to the deoxy-AP site. Together, this work provides molecular level insights into rAP processing by APE1 and advances our understanding of ribonucleotide processing within genomic DNA.
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12
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Wallace SS. Molecular radiobiology and the origins of the base excision repair pathway: an historical perspective. Int J Radiat Biol 2021; 99:891-902. [DOI: 10.1080/09553002.2021.1908639] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Susan S. Wallace
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, USA
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13
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Patel PS, Algouneh A, Hakem R. Exploiting synthetic lethality to target BRCA1/2-deficient tumors: where we stand. Oncogene 2021; 40:3001-3014. [PMID: 33716297 DOI: 10.1038/s41388-021-01744-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/21/2021] [Accepted: 02/26/2021] [Indexed: 12/11/2022]
Abstract
The principle of synthetic lethality, which refers to the loss of viability resulting from the disruption of two genes, which, individually, do not cause lethality, has become an attractive target approach due to the development and clinical success of Poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi). In this review, we present the most recent findings on the use of PARPi in the clinic, which are currently approved for second-line therapy for advanced ovarian and breast cancer associated with mutations of BRCA1 or BRCA2 (BRCA1/2) genes. PARPi efficacy, however, appears to be limited by acquired and inherent resistance, highlighting the need for alternative and synergistic targets to eliminate these tumors. Here, we explore other identified synthetic lethal interactors of BRCA1/2, including DNA polymerase theta (POLQ), Fanconi anemia complementation group D2 (FANDC2), radiation sensitive 52 (RAD52), Flap structure-specific endonuclease 1 (FEN1), and apurinic/apyrimidinic endodeoxyribonuclease 2 (APE2), as well as other protein and nonprotein targets, for BRCA1/2-mutated cancers and their implications for future therapies. A wealth of information now exists for phenotypic and functional characterization of these novel synthetic lethal interactors of BRCA1/2, and leveraging these findings can pave the way for the development of new targeted therapies for patients suffering from these cancers.
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Affiliation(s)
- Parasvi S Patel
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Arash Algouneh
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Razq Hakem
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
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14
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Hu Y, Yang C, Amorim T, Maqbool M, Lin J, Li C, Fang C, Xue L, Kwart A, Fang H, Yin M, Janocha AJ, Tsuchimoto D, Nakabeppu Y, Jiang X, Mejia-Garcia A, Anwer F, Khouri J, Qi X, Zheng QY, Yu JS, Yan S, LaFramboise T, Anderson KC, Herlitz LC, Munshi NC, Lin J, Zhao J. Cisplatin-Mediated Upregulation of APE2 Binding to MYH9 Provokes Mitochondrial Fragmentation and Acute Kidney Injury. Cancer Res 2021; 81:713-723. [PMID: 33288657 PMCID: PMC7869671 DOI: 10.1158/0008-5472.can-20-1010] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 09/29/2020] [Accepted: 12/02/2020] [Indexed: 11/16/2022]
Abstract
Cisplatin chemotherapy is standard care for many cancers but is toxic to the kidneys. How this toxicity occurs is uncertain. In this study, we identified apurinic/apyrimidinic endonuclease 2 (APE2) as a critical molecule upregulated in the proximal tubule cells (PTC) following cisplatin-induced nuclear DNA and mitochondrial DNA damage in cisplatin-treated C57B6J mice. The APE2 transgenic mouse phenotype recapitulated the pathophysiological features of C-AKI (acute kidney injury, AKI) in the absence of cisplatin treatment. APE2 pulldown-MS analysis revealed that APE2 binds myosin heavy-Chain 9 (MYH9) protein in mitochondria after cisplatin treatment. Human MYH9-related disorder is caused by mutations in MYH9 that eventually lead to nephritis, macrothrombocytopenia, and deafness, a constellation of symptoms similar to the toxicity profile of cisplatin. Moreover, cisplatin-induced C-AKI was attenuated in APE2-knockout mice. Taken together, these findings suggest that cisplatin promotes AKI development by upregulating APE2, which leads to subsequent MYH9 dysfunction in PTC mitochondria due to an unrelated role of APE2 in DNA damage repair. This postulated mechanism and the availability of an engineered transgenic mouse model based on the mechanism of C-AKI provides an opportunity to identify novel targets for prophylactic treatment of this serious disease. SIGNIFICANCE: These results reveal and highlight an unexpected role of APE2 via its interaction with MYH9 and suggest that APE2 has the potential to prevent acute kidney injury in patients with cisplatin-treated cancer. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/3/713/F1.large.jpg.
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Affiliation(s)
- Yi Hu
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Chun Yang
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts
- Department of Clinical Laboratory, the 4th Hospital of Harbin Medical University, Harbin, China
| | - Tania Amorim
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Mohsin Maqbool
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Jenny Lin
- Department of Medicine, University of California San Diego, La Jolla, California
| | - Chen Li
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
- College of Food Science and Technology, Agricultural University of Hebei, Baoding, Hebei, China
| | - Chuanfeng Fang
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
- Department of Clinical Laboratory, the 4th Hospital of Harbin Medical University, Harbin, China
| | - Li Xue
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts
- Department of Clinical Laboratory, the 4th Hospital of Harbin Medical University, Harbin, China
| | - Ariel Kwart
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts
- Division of Hand Surgery, Department of Orthopedic Surgery, NYU Langone Orthopedic Hospital, New York, New York
| | - Hua Fang
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Mei Yin
- Image Core, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Allison J Janocha
- The Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Daisuke Tsuchimoto
- Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Higashi-ku, Japan
| | - Yusaku Nakabeppu
- Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Higashi-ku, Japan
| | - Xiaofeng Jiang
- Department of Clinical Laboratory, the 4th Hospital of Harbin Medical University, Harbin, China
| | - Alex Mejia-Garcia
- Department of Hematology and Medical Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
| | - Faiz Anwer
- Department of Hematology and Medical Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
| | - Jack Khouri
- Department of Hematology and Medical Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
| | - Xin Qi
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Qing Y Zheng
- Department of Otolaryngology-Head and Neck Surgery, Case Western Reserve University, Cleveland, Ohio
| | - Jennifer S Yu
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
- Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina
| | - Thomas LaFramboise
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Kenneth C Anderson
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts
| | - Leal C Herlitz
- Department of Laboratory Medicine, Robert J. Tomsich Pathology and Laboratory Medicine Institute, Cleveland Clinic, Cleveland, Ohio
| | - Nikhil C Munshi
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts
- VA Boston Healthcare System, Boston, Massachusetts
| | - Jianhong Lin
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, Ohio.
| | - Jianjun Zhao
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio.
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Elsakrmy N, Zhang-Akiyama QM, Ramotar D. The Base Excision Repair Pathway in the Nematode Caenorhabditis elegans. Front Cell Dev Biol 2020; 8:598860. [PMID: 33344454 PMCID: PMC7744777 DOI: 10.3389/fcell.2020.598860] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 11/09/2020] [Indexed: 12/12/2022] Open
Abstract
Exogenous and endogenous damage to the DNA is inevitable. Several DNA repair pathways including base excision, nucleotide excision, mismatch, homologous and non-homologous recombinations are conserved across all organisms to faithfully maintain the integrity of the genome. The base excision repair (BER) pathway functions to repair single-base DNA lesions and during the process creates the premutagenic apurinic/apyrimidinic (AP) sites. In this review, we discuss the components of the BER pathway in the nematode Caenorhabditis elegans and delineate the different phenotypes caused by the deletion or the knockdown of the respective DNA repair gene, as well as the implications. To date, two DNA glycosylases have been identified in C. elegans, the monofunctional uracil DNA glycosylase-1 (UNG-1) and the bifunctional endonuclease III-1 (NTH-1) with associated AP lyase activity. In addition, the animal possesses two AP endonucleases belonging to the exonuclease-3 and endonuclease IV families and in C. elegans these enzymes are called EXO-3 and APN-1, respectively. In mammalian cells, the DNA polymerase, Pol beta, that is required to reinsert the correct bases for DNA repair synthesis is not found in the genome of C. elegans and the evidence indicates that this role could be substituted by DNA polymerase theta (POLQ), which is known to perform a function in the microhomology-mediated end-joining pathway in human cells. The phenotypes observed by the C. elegans mutant strains of the BER pathway raised many challenging questions including the possibility that the DNA glycosylases may have broader functional roles, as discuss in this review.
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Affiliation(s)
- Noha Elsakrmy
- Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Education City, Qatar
| | - Qiu-Mei Zhang-Akiyama
- Laboratory of Stress Response Biology, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Dindial Ramotar
- Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Education City, Qatar
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16
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Lin Y, McMahon A, Driscoll G, Bullock S, Zhao J, Yan S. Function and molecular mechanisms of APE2 in genome and epigenome integrity. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2020; 787:108347. [PMID: 34083046 DOI: 10.1016/j.mrrev.2020.108347] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/30/2020] [Accepted: 11/10/2020] [Indexed: 02/06/2023]
Abstract
APE2 is a rising vital player in the maintenance of genome and epigenome integrity. In the past several years, a series of studies have shown the critical roles and functions of APE2. We seek to provide the first comprehensive review on several aspects of APE2 in genome and epigenome integrity. We first summarize the distinct functional domains or motifs within APE2 including EEP (endonuclease/exonuclease/phosphatase) domain, PIP box and Zf-GRF motifs from eight species (i.e., Homo sapiens, Mus musculus, Xenopus laevis, Ciona intestinalis, Arabidopsis thaliana, Schizosaccharomyces pombe, Saccharomyces cerevisiae, and Trypanosoma cruzi). Then we analyze various APE2 nuclease activities and associated DNA substrates, including AP endonuclease, 3'-phosphodiesterase, 3'-phosphatase, and 3'-5' exonuclease activities. We also examine several APE2 interaction proteins, including PCNA, Chk1, APE1, Myh1, and homologous recombination (HR) factors such as Rad51, Rad52, BRCA1, BRCA2, and BARD1. Furthermore, we provide insights into the roles of APE2 in various DNA repair pathways (base excision repair, single-strand break repair, and double-strand break repair), DNA damage response (DDR) pathways (ATR-Chk1 and p53-dependent), immunoglobulin class switch recombination and somatic hypermutation, as well as active DNA demethylation. Lastly, we summarize critical functions of APE2 in growth, development, and diseases. In this review, we provide the first comprehensive perspective which dissects all aspects of the multiple-function protein APE2 in genome and epigenome integrity.
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Affiliation(s)
- Yunfeng Lin
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, 28223, United States
| | - Anne McMahon
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, 28223, United States
| | - Garrett Driscoll
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, 28223, United States
| | - Sharon Bullock
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, 28223, United States
| | - Jianjun Zhao
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, 44195, United States
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, 28223, United States.
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17
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Ha A, Lin Y, Yan S. A non-canonical role for the DNA glycosylase NEIL3 in suppressing APE1 endonuclease-mediated ssDNA damage. J Biol Chem 2020; 295:14222-14235. [PMID: 32817342 DOI: 10.1074/jbc.ra120.014228] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/11/2020] [Indexed: 12/21/2022] Open
Abstract
The DNA glycosylase NEIL3 has been implicated in DNA repair pathways including the base excision repair and the interstrand cross-link repair pathways via its DNA glycosylase and/or AP lyase activity, which are considered canonical roles of NEIL3 in genome integrity. Compared with the other DNA glycosylases NEIL1 and NEIL2, Xenopus laevis NEIL3 C terminus has two highly conserved zinc finger motifs containing GRXF residues (designated as Zf-GRF). It has been demonstrated that the minor AP endonuclease APE2 contains only one Zf-GRF motif mediating interaction with single-strand DNA (ssDNA), whereas the major AP endonuclease APE1 does not. It appears that the two NEIL3 Zf-GRF motifs (designated as Zf-GRF repeat) are dispensable for its DNA glycosylase and AP lyase activity; however, the potential function of the NEIL3 Zf-GRF repeat in genome integrity remains unknown. Here, we demonstrate evidence that the NEIL3 Zf-GRF repeat was associated with a higher affinity for shorter ssDNA than one single Zf-GRF motif. Notably, our protein-protein interaction assays show that the NEIL3 Zf-GRF repeat but not one Zf-GRF motif interacted with APE1 but not APE2. We further reveal that APE1 endonuclease activity on ssDNA but not on dsDNA is compromised by a NEIL3 Zf-GRF repeat, whereas one Zf-GRF motif within NEIL3 is not sufficient to prevent such activity of APE1. In addition, COMET assays show that excess NEIL3 Zf-GRF repeat reduces DNA damage in oxidative stress in Xenopus egg extracts. Together, our results suggest a noncanonical role of NEIL3 in genome integrity via its distinct Zf-GRF repeat in suppressing APE1 endonuclease-mediated ssDNA breakage.
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Affiliation(s)
- Anh Ha
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA
| | - Yunfeng Lin
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA
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18
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Álvarez-Quilón A, Wojtaszek JL, Mathieu MC, Patel T, Appel CD, Hustedt N, Rossi SE, Wallace BD, Setiaputra D, Adam S, Ohashi Y, Melo H, Cho T, Gervais C, Muñoz IM, Grazzini E, Young JTF, Rouse J, Zinda M, Williams RS, Durocher D. Endogenous DNA 3' Blocks Are Vulnerabilities for BRCA1 and BRCA2 Deficiency and Are Reversed by the APE2 Nuclease. Mol Cell 2020; 78:1152-1165.e8. [PMID: 32516598 PMCID: PMC7340272 DOI: 10.1016/j.molcel.2020.05.021] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/18/2020] [Accepted: 05/13/2020] [Indexed: 02/08/2023]
Abstract
The APEX2 gene encodes APE2, a nuclease related to APE1, the apurinic/apyrimidinic endonuclease acting in base excision repair. Loss of APE2 is lethal in cells with mutated BRCA1 or BRCA2, making APE2 a prime target for homologous recombination-defective cancers. However, because the function of APE2 in DNA repair is poorly understood, it is unclear why BRCA-deficient cells require APE2 for viability. Here we present the genetic interaction profiles of APE2, APE1, and TDP1 deficiency coupled to biochemical and structural dissection of APE2. We conclude that the main role of APE2 is to reverse blocked 3' DNA ends, problematic lesions that preclude DNA synthesis. Our work also suggests that TOP1 processing of genomic ribonucleotides is the main source of 3'-blocking lesions relevant to APEX2-BRCA1/2 synthetic lethality. The exquisite sensitivity of BRCA-deficient cells to 3' blocks indicates that they represent a tractable vulnerability in homologous recombination-deficient tumor cells.
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Affiliation(s)
- Alejandro Álvarez-Quilón
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Jessica L Wojtaszek
- Structural Cell Biology Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, 111 TW Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Marie-Claude Mathieu
- Repare Therapeutics, 7210 Frederick-Banting, Suite 100, St-Laurent, QC H4S 2A1, Canada
| | - Tejas Patel
- Structural Cell Biology Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, 111 TW Alexander Drive, Research Triangle Park, NC 27709, USA
| | - C Denise Appel
- Structural Cell Biology Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, 111 TW Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Nicole Hustedt
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Silvia Emma Rossi
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Bret D Wallace
- Structural Cell Biology Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, 111 TW Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Dheva Setiaputra
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Salomé Adam
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Yota Ohashi
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Henrique Melo
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada
| | - Tiffany Cho
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Christian Gervais
- National Research Council Canada Human Health Therapeutics Research Center, 6100 Royalmount Avenue, Montreal, QC H4P 2R2, Canada
| | - Ivan M Muñoz
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Eric Grazzini
- National Research Council Canada Human Health Therapeutics Research Center, 6100 Royalmount Avenue, Montreal, QC H4P 2R2, Canada
| | - Jordan T F Young
- Repare Therapeutics, 7210 Frederick-Banting, Suite 100, St-Laurent, QC H4S 2A1, Canada
| | - John Rouse
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Michael Zinda
- Repare Therapeutics, 7210 Frederick-Banting, Suite 100, St-Laurent, QC H4S 2A1, Canada
| | - R Scott Williams
- Structural Cell Biology Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, US Department of Health and Human Services, 111 TW Alexander Drive, Research Triangle Park, NC 27709, USA.
| | - Daniel Durocher
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada; Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada.
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19
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Stratigopoulou M, van Dam TP, Guikema JEJ. Base Excision Repair in the Immune System: Small DNA Lesions With Big Consequences. Front Immunol 2020; 11:1084. [PMID: 32547565 PMCID: PMC7272602 DOI: 10.3389/fimmu.2020.01084] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 05/05/2020] [Indexed: 12/13/2022] Open
Abstract
The integrity of the genome is under constant threat of environmental and endogenous agents that cause DNA damage. Endogenous damage is particularly pervasive, occurring at an estimated rate of 10,000–30,000 per cell/per day, and mostly involves chemical DNA base lesions caused by oxidation, depurination, alkylation, and deamination. The base excision repair (BER) pathway is primary responsible for removing and repairing these small base lesions that would otherwise lead to mutations or DNA breaks during replication. Next to preventing DNA mutations and damage, the BER pathway is also involved in mutagenic processes in B cells during immunoglobulin (Ig) class switch recombination (CSR) and somatic hypermutation (SHM), which are instigated by uracil (U) lesions derived from activation-induced cytidine deaminase (AID) activity. BER is required for the processing of AID-induced lesions into DNA double strand breaks (DSB) that are required for CSR, and is of pivotal importance for determining the mutagenic outcome of uracil lesions during SHM. Although uracils are generally efficiently repaired by error-free BER, this process is surprisingly error-prone at the Ig loci in proliferating B cells. Breakdown of this high-fidelity process outside of the Ig loci has been linked to mutations observed in B-cell tumors and DNA breaks and chromosomal translocations in activated B cells. Next to its role in preventing cancer, BER has also been implicated in immune tolerance. Several defects in BER components have been associated with autoimmune diseases, and animal models have shown that BER defects can cause autoimmunity in a B-cell intrinsic and extrinsic fashion. In this review we discuss the contribution of BER to genomic integrity in the context of immune receptor diversification, cancer and autoimmune diseases.
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Affiliation(s)
- Maria Stratigopoulou
- Department of Pathology, Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Tijmen P van Dam
- Department of Pathology, Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Jeroen E J Guikema
- Department of Pathology, Lymphoma and Myeloma Center Amsterdam (LYMMCARE), Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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20
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Srivastava M, Su D, Zhang H, Chen Z, Tang M, Nie L, Chen J. HMCES safeguards replication from oxidative stress and ensures error-free repair. EMBO Rep 2020; 21:e49123. [PMID: 32307824 DOI: 10.15252/embr.201949123] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 03/14/2020] [Accepted: 03/19/2020] [Indexed: 02/02/2023] Open
Abstract
Replication across oxidative DNA lesions can give rise to mutations that pose a threat to genome integrity. How such lesions, which escape base excision repair, get removed without error during replication remains unknown. Our PCNA-based screen to uncover changes in replisome composition under different replication stress conditions had revealed a previously unknown PCNA-interacting protein, HMCES/C3orf37. Here, we show that HMCES is a critical component of the replication stress response, mainly upon base misincorporation. We further demonstrate that the absence of HMCES imparts resistance to pemetrexed treatment due to error-prone bypass of oxidative damage. Furthermore, based on genetic screening, we show that homologous recombination repair proteins, such as CtIP, BRCA2, BRCA1, and PALB2, are indispensable for the survival of HMCES KO cells. Hence, HMCES, which is the sole member of the SRAP superfamily in higher eukaryotes known so far, acts as a proofreader on replication forks, facilitates resolution of oxidative base damage, and therefore ensures faithful DNA replication.
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Affiliation(s)
- Mrinal Srivastava
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Dan Su
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Huimin Zhang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Zhen Chen
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Mengfan Tang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Litong Nie
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Junjie Chen
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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21
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Lin Y, Raj J, Li J, Ha A, Hossain MA, Richardson C, Mukherjee P, Yan S. APE1 senses DNA single-strand breaks for repair and signaling. Nucleic Acids Res 2020; 48:1925-1940. [PMID: 31828326 PMCID: PMC7038996 DOI: 10.1093/nar/gkz1175] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 12/02/2019] [Accepted: 12/05/2019] [Indexed: 02/06/2023] Open
Abstract
DNA single-strand breaks (SSBs) represent the most abundant type of DNA damage. Unrepaired SSBs impair DNA replication and transcription, leading to cancer and neurodegenerative disorders. Although PARP1 and XRCC1 are implicated in the SSB repair pathway, it remains unclear how SSB repair and SSB signaling pathways are coordinated and regulated. Using Xenopus egg extract and in vitro reconstitution systems, here we show that SSBs are first sensed by APE1 to initiate 3'-5' SSB end resection, followed by APE2 recruitment to continue SSB end resection. Notably, APE1's exonuclease activity is critical for SSB repair and SSB signaling pathways. An APE1 exonuclease-deficient mutant identified in somatic tissue from a cancer patient highlighted the significance of APE1 exonuclease activity in cancer etiology. In addition, APE1 interacts with APE2 and PCNA, although PCNA is dispensable for APE1's exonuclease activity. Taken together, we propose a two-step APE1/APE2-mediated mechanism for SSB end resection that couples DNA damage response with SSB repair in a eukaryotic system.
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Affiliation(s)
- Yunfeng Lin
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Jude Raj
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Jia Li
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Anh Ha
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Md Akram Hossain
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Christine Richardson
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Pinku Mukherjee
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
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22
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Genomic alterations and abnormal expression of APE2 in multiple cancers. Sci Rep 2020; 10:3758. [PMID: 32111912 PMCID: PMC7048847 DOI: 10.1038/s41598-020-60656-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/13/2020] [Indexed: 12/26/2022] Open
Abstract
Although APE2 plays essential roles in base excision repair and ATR-Chk1 DNA damage response (DDR) pathways, it remains unknown how the APE2 gene is altered in the human genome and whether APE2 is differentially expressed in cancer patients. Here, we report multiple-cancer analyses of APE2 genomic alterations and mRNA expression from cancer patients using available data from The Cancer Genome Atlas (TCGA). We observe that APE2 genomic alterations occur at ~17% frequency in 14 cancer types (n = 21,769). Most frequent somatic mutations of APE2 appear in uterus (2.89%) and skin (2.47%) tumor samples. Furthermore, APE2 expression is upregulated in tumor tissue compared with matched non-malignant tissue across 5 cancer types including kidney, breast, lung, liver, and uterine cancers, but not in prostate cancer. We also examine the mRNA expression of 13 other DNA repair and DDR genes from matched samples for 6 cancer types. We show that APE2 mRNA expression is positively correlated with PCNA, APE1, XRCC1, PARP1, Chk1, and Chk2 across these 6 tumor tissue types; however, groupings of other DNA repair and DDR genes are correlated with APE2 with different patterns in different cancer types. Taken together, this study demonstrates alterations and abnormal expression of APE2 from multiple cancers.
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23
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Edwards RH, Dekroon R, Raab-Traub N. Alterations in cellular expression in EBV infected epithelial cell lines and tumors. PLoS Pathog 2019; 15:e1008071. [PMID: 31584998 PMCID: PMC6795468 DOI: 10.1371/journal.ppat.1008071] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 10/16/2019] [Accepted: 09/04/2019] [Indexed: 12/15/2022] Open
Abstract
The Epstein Barr virus (EBV) is linked to the development of two major epithelial malignancies, gastric carcinoma and nasopharyngeal carcinoma. This study evaluates the effects of EBV on cellular expression in a gastric epithelial cell line infected with or without EBV and a nasopharyngeal carcinoma cell line containing EBV. The cells were grown in vitro and as tumors in vivo. The effects on cellular expression were determined using both 2D DIGE proteomics and high throughput RNA sequencing. The data identify multiple pathways that were uniquely activated in vitro. RNA sequences mapping to the mouse genome were identified in both the EBV positive and negative tumor samples in vivo, although, differences between the EBV positive and negative cells were not apparent. However, the tumors appeared to be grossly distinct. The majority of the identified canonical pathways based on two fold changes in expression had decreased activity within the tumors in vivo. Identification of the predicted upstream regulating factors revealed that in vitro the regulating factors were primarily protein transcriptional regulators. In contrast, in vivo the predicted regulators were frequently noncoding RNAs. Hierarchical clustering distinguished the cell lines and tumors, the EBV positive tumors from the EBV negative tumors, and the NPC tumors from the gastric tumors and cell lines. The delineating genes were changed greater than 4 fold and were frequently regulated by protein transcription factors. These data suggest that EBV distinctly affects cellular expression in gastric tumors and NPC and that growth in vivo requires activation of fewer cellular signaling pathways. It is likely that the broad changes in cellular expression that occur at low levels are controlled by regulatory viral and cellular RNAs while major changes are affected by induced protein regulators.
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Affiliation(s)
- Rachel Hood Edwards
- Lineberger Comprehensive Cancer Center University of North Carolina at Chapel Hill Chapel Hill, North Carolina, United States of America
| | - Robert Dekroon
- Lineberger Comprehensive Cancer Center University of North Carolina at Chapel Hill Chapel Hill, North Carolina, United States of America
| | - Nancy Raab-Traub
- Lineberger Comprehensive Cancer Center University of North Carolina at Chapel Hill Chapel Hill, North Carolina, United States of America
- Department of Microbiology & Immunology University of North Carolina at Chapel Hill Chapel Hill, North Carolina, United States of America
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24
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Lin Y, Bai L, Cupello S, Hossain MA, Deem B, McLeod M, Raj J, Yan S. APE2 promotes DNA damage response pathway from a single-strand break. Nucleic Acids Res 2019; 46:2479-2494. [PMID: 29361157 PMCID: PMC5861430 DOI: 10.1093/nar/gky020] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 01/09/2018] [Indexed: 02/06/2023] Open
Abstract
As the most common type of DNA damage, DNA single-strand breaks (SSBs) are primarily repaired by the SSB repair mechanism. If not repaired properly or promptly, unrepaired SSBs lead to genome stability and have been implicated in cancer and neurodegenerative diseases. However, it remains unknown how unrepaired SSBs are recognized by DNA damage response (DDR) pathway, largely because of the lack of a feasible experimental system. Here, we demonstrate evidence showing that an ATR-dependent checkpoint signaling is activated by a defined plasmid-based site-specific SSB structure in Xenopus HSS (high-speed supernatant) system. Notably, the distinct SSB signaling requires APE2 and canonical checkpoint proteins, including ATR, ATRIP, TopBP1, Rad9 and Claspin. Importantly, the SSB-induced ATR DDR is essential for SSB repair. We and others show that APE2 interacts with PCNA via its PIP box and preferentially interacts with ssDNA via its C-terminus Zf–GRF domain, a conserved motif found in >100 proteins involved in DNA/RNA metabolism. Here, we identify a novel mode of APE2–PCNA interaction via APE2 Zf–GRF and PCNA C-terminus. Mechanistically, the APE2 Zf–GRF–PCNA interaction facilitates 3′-5′ SSB end resection, checkpoint protein complex assembly, and SSB-induced DDR pathway. Together, we propose that APE2 promotes ATR–Chk1 DDR pathway from a single-strand break.
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Affiliation(s)
- Yunfeng Lin
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Liping Bai
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Steven Cupello
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Md Akram Hossain
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Bradley Deem
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Melissa McLeod
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Jude Raj
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
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25
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Abstract
Ribonucleotides that are mis-incorporated into DNA during replication are removed by Topoisomerase 1, which generates 3’ terminal adducts that are not amenable to DNA repair and thus compromise genome stability. A recent report by Niu and colleagues reveals that Apn2/APE2 resolves such blocked 3’-termini to suppress Top1-induced mutations at rNMP sites within the genome.
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Affiliation(s)
- Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, USA.
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26
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Mengwasser KE, Adeyemi RO, Leng Y, Choi MY, Clairmont C, D'Andrea AD, Elledge SJ. Genetic Screens Reveal FEN1 and APEX2 as BRCA2 Synthetic Lethal Targets. Mol Cell 2019. [PMID: 30686591 DOI: 10.1016/j.molcel.2018.12.008]] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BRCA1 or BRCA2 inactivation drives breast and ovarian cancer but also creates vulnerability to poly(ADP-ribose) polymerase (PARP) inhibitors. To search for additional targets whose inhibition is synthetically lethal in BRCA2-deficient backgrounds, we screened two pairs of BRCA2 isogenic cell lines with DNA-repair-focused small hairpin RNA (shRNA) and CRISPR (clustered regularly interspaced short palindromic repeats)-based libraries. We found that BRCA2-deficient cells are selectively dependent on multiple pathways including base excision repair, ATR signaling, and splicing. We identified APEX2 and FEN1 as synthetic lethal genes with both BRCA1 and BRCA2 loss of function. BRCA2-deficient cells require the apurinic endonuclease activity and the PCNA-binding domain of Ape2 (APEX2), but not Ape1 (APEX1). Furthermore, BRCA2-deficient cells require the 5' flap endonuclease but not the 5'-3' exonuclease activity of Fen1, and chemically inhibiting Fen1 selectively targets BRCA-deficient cells. Finally, we developed a microhomology-mediated end-joining (MMEJ) reporter and showed that Fen1 participates in MMEJ, underscoring the importance of MMEJ as a collateral repair pathway in the context of homologous recombination (HR) deficiency.
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Affiliation(s)
- Kristen E Mengwasser
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Richard O Adeyemi
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Yumei Leng
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Mei Yuk Choi
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Connor Clairmont
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Alan D D'Andrea
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Stephen J Elledge
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA.
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27
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Mengwasser KE, Adeyemi RO, Leng Y, Choi MY, Clairmont C, D'Andrea AD, Elledge SJ. Genetic Screens Reveal FEN1 and APEX2 as BRCA2 Synthetic Lethal Targets. Mol Cell 2019; 73:885-899.e6. [PMID: 30686591 DOI: 10.1016/j.molcel.2018.12.008] [Citation(s) in RCA: 131] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 09/24/2018] [Accepted: 12/12/2018] [Indexed: 11/15/2022]
Abstract
BRCA1 or BRCA2 inactivation drives breast and ovarian cancer but also creates vulnerability to poly(ADP-ribose) polymerase (PARP) inhibitors. To search for additional targets whose inhibition is synthetically lethal in BRCA2-deficient backgrounds, we screened two pairs of BRCA2 isogenic cell lines with DNA-repair-focused small hairpin RNA (shRNA) and CRISPR (clustered regularly interspaced short palindromic repeats)-based libraries. We found that BRCA2-deficient cells are selectively dependent on multiple pathways including base excision repair, ATR signaling, and splicing. We identified APEX2 and FEN1 as synthetic lethal genes with both BRCA1 and BRCA2 loss of function. BRCA2-deficient cells require the apurinic endonuclease activity and the PCNA-binding domain of Ape2 (APEX2), but not Ape1 (APEX1). Furthermore, BRCA2-deficient cells require the 5' flap endonuclease but not the 5'-3' exonuclease activity of Fen1, and chemically inhibiting Fen1 selectively targets BRCA-deficient cells. Finally, we developed a microhomology-mediated end-joining (MMEJ) reporter and showed that Fen1 participates in MMEJ, underscoring the importance of MMEJ as a collateral repair pathway in the context of homologous recombination (HR) deficiency.
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Affiliation(s)
- Kristen E Mengwasser
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Richard O Adeyemi
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Yumei Leng
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Mei Yuk Choi
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Connor Clairmont
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Alan D D'Andrea
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
| | - Stephen J Elledge
- Howard Hughes Medical Institute, Department of Genetics, Ludwig Center, Harvard Medical School, Boston, MA 02115, USA; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA.
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28
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Abstract
Before a deleterious DNA lesion can be replaced with its undamaged counterpart, the lesion must first be removed from the genome. This process of removing and replacing DNA lesions is accomplished by the careful coordination of several protein factors during DNA repair. One such factor is the multifunctional enzyme human apurinic/apyrimidinic endonuclease 1 (APE1), known best for its DNA backbone cleavage activity at AP sites during base excision repair (BER). APE1 preforms AP site incision with surgical precision and skill, by sculpting the DNA to place the cleavage site in an optimal position for nucleophilic attack within its compact protein active site. APE1, however, has demonstrated broad surgical expertise, and applies its DNA cleavage activity to a wide variety of DNA and RNA substrates. Here, we discuss what is known and unknown about APE1 cleavage mechanisms, focusing on structural and mechanistic considerations. Importantly, disruptions in the biological functions associated with APE1 are linked to numerous human maladies, including cancer and neurodegenerative diseases. The continued elucidation of APE1 mechanisms is required for rational drug design towards novel and strategic ways to target its associated repair pathways.
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Affiliation(s)
- Amy M Whitaker
- Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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29
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Li J, Liang W, Li Y, Qian W. APURINIC/APYRIMIDINIC ENDONUCLEASE2 and ZINC FINGER DNA 3'-PHOSPHOESTERASE Play Overlapping Roles in the Maintenance of Epigenome and Genome Stability. THE PLANT CELL 2018; 30:1954-1970. [PMID: 30135084 PMCID: PMC6181018 DOI: 10.1105/tpc.18.00287] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/19/2018] [Accepted: 08/22/2018] [Indexed: 05/21/2023]
Abstract
Base excision repair (BER) is essential for active DNA demethylation and DNA damage repair in mammals and plants. Here, we provide genetic and biochemical evidence that APURINIC/APYRIMIDINIC ENDONUCLEASE2 (APE2) plays overlapping roles with ZINC FINGER DNA 3'-PHOSPHOESTERASE (ZDP) in active DNA demethylation and DNA damage repair in Arabidopsis thaliana Simultaneous mutation of APE2 and ZDP causes DNA hypermethylation at more than 2000 loci, most of which are not hypermethylated in ape2 or zdp single mutants. The zdp and ape2 single mutants exhibit normal development, but the zdp ape2 double mutants display pleiotropic developmental defects and are supersensitive to the DNA alkylating reagent methyl methanesulfonate. The gradual accumulation of DNA lesions in the zdp ape2 seedlings is accompanied by constitutive activation of the DNA damage response and alteration of the cell cycle. Interestingly, knockout of the key DNA demethylase REPRESSOR OF SILENCING1 reduces the magnitude of DNA lesion accumulation and the DNA damage response in the zdp ape2 mutants, suggesting that a proportion of the DNA damage in the zdp ape2 mutants arises from incomplete active DNA demethylation. Lastly, we find that APE2 has 3'-phosphatase activity and strong 3'-5' exonuclease activity in vitro. Together, our results suggest that APE2 and ZDP, two BER proteins, play overlapping roles in the maintenance of epigenome and genome stability in plants.
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Affiliation(s)
- Jinchao Li
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
| | - Wenjie Liang
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
| | - Yan Li
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Weiqiang Qian
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
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30
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Hossain MA, Lin Y, Yan S. Single-Strand Break End Resection in Genome Integrity: Mechanism and Regulation by APE2. Int J Mol Sci 2018; 19:ijms19082389. [PMID: 30110897 PMCID: PMC6122073 DOI: 10.3390/ijms19082389] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/07/2018] [Accepted: 08/11/2018] [Indexed: 12/22/2022] Open
Abstract
DNA single-strand breaks (SSBs) occur more than 10,000 times per mammalian cell each day, representing the most common type of DNA damage. Unrepaired SSBs compromise DNA replication and transcription programs, leading to genome instability. Unrepaired SSBs are associated with diseases such as cancer and neurodegenerative disorders. Although canonical SSB repair pathway is activated to repair most SSBs, it remains unclear whether and how unrepaired SSBs are sensed and signaled. In this review, we propose a new concept of SSB end resection for genome integrity. We propose a four-step mechanism of SSB end resection: SSB end sensing and processing, as well as initiation, continuation, and termination of SSB end resection. We also compare different mechanisms of SSB end resection and DSB end resection in DNA repair and DNA damage response (DDR) pathways. We further discuss how SSB end resection contributes to SSB signaling and repair. We focus on the mechanism and regulation by APE2 in SSB end resection in genome integrity. Finally, we identify areas of future study that may help us gain further mechanistic insight into the process of SSB end resection. Overall, this review provides the first comprehensive perspective on SSB end resection in genome integrity.
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Affiliation(s)
- Md Akram Hossain
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
| | - Yunfeng Lin
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
| | - Shan Yan
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
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31
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Chakraborty U, Dinh TA, Alani E. Genomic Instability Promoted by Overexpression of Mismatch Repair Factors in Yeast: A Model for Understanding Cancer Progression. Genetics 2018; 209:439-456. [PMID: 29654124 PMCID: PMC5972419 DOI: 10.1534/genetics.118.300923] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 04/12/2018] [Indexed: 02/04/2023] Open
Abstract
Mismatch repair (MMR) proteins act in spellchecker roles to excise misincorporation errors that occur during DNA replication. Curiously, large-scale analyses of a variety of cancers showed that increased expression of MMR proteins often correlated with tumor aggressiveness, metastasis, and early recurrence. To better understand these observations, we used The Cancer Genome Atlas and Gene Expression across Normal and Tumor tissue databases to analyze MMR protein expression in cancers. We found that the MMR genes MSH2 and MSH6 are overexpressed more frequently than MSH3, and that MSH2 and MSH6 are often cooverexpressed as a result of copy number amplifications of these genes. These observations encouraged us to test the effects of upregulating MMR protein levels in baker's yeast, where we can sensitively monitor genome instability phenotypes associated with cancer initiation and progression. Msh6 overexpression (two- to fourfold) almost completely disrupted mechanisms that prevent recombination between divergent DNA sequences by interacting with the DNA polymerase processivity clamp PCNA and by sequestering the Sgs1 helicase. Importantly, cooverexpression of Msh2 and Msh6 (∼eightfold) conferred, in a PCNA interaction-dependent manner, several genome instability phenotypes including increased mutation rate, increased sensitivity to the DNA replication inhibitor HU and the DNA-damaging agents MMS and 4-nitroquinoline N-oxide, and elevated loss-of-heterozygosity. Msh2 and Msh6 cooverexpression also altered the cell cycle distribution of exponentially growing cells, resulting in an increased fraction of unbudded cells, consistent with a larger percentage of cells in G1. These novel observations suggested that overexpression of MSH factors affected the integrity of the DNA replication fork, causing genome instability phenotypes that could be important for promoting cancer progression.
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Affiliation(s)
- Ujani Chakraborty
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853-2703
| | - Timothy A Dinh
- Curriculum in Genetics and Molecular Biology, Biological and Biomedical Sciences Program, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Eric Alani
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853-2703
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32
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Murray V, Chen JK, Chung LH. The Interaction of the Metallo-Glycopeptide Anti-Tumour Drug Bleomycin with DNA. Int J Mol Sci 2018; 19:E1372. [PMID: 29734689 PMCID: PMC5983701 DOI: 10.3390/ijms19051372] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 04/24/2018] [Accepted: 04/24/2018] [Indexed: 11/17/2022] Open
Abstract
The cancer chemotherapeutic drug, bleomycin, is clinically used to treat several neoplasms including testicular and ovarian cancers. Bleomycin is a metallo-glycopeptide antibiotic that requires a transition metal ion, usually Fe(II), for activity. In this review, the properties of bleomycin are examined, especially the interaction of bleomycin with DNA. A Fe(II)-bleomycin complex is capable of DNA cleavage and this process is thought to be the major determinant for the cytotoxicity of bleomycin. The DNA sequence specificity of bleomycin cleavage is found to at 5′-GT* and 5′-GC* dinucleotides (where * indicates the cleaved nucleotide). Using next-generation DNA sequencing, over 200 million double-strand breaks were analysed, and an expanded bleomycin sequence specificity was found to be 5′-RTGT*AY (where R is G or A and Y is T or C) in cellular DNA and 5′-TGT*AT in purified DNA. The different environment of cellular DNA compared to purified DNA was proposed to be responsible for the difference. A number of bleomycin analogues have been examined and their interaction with DNA is also discussed. In particular, the production of bleomycin analogues via genetic manipulation of the modular non-ribosomal peptide synthetases and polyketide synthases in the bleomycin gene cluster is reviewed. The prospects for the synthesis of bleomycin analogues with increased effectiveness as cancer chemotherapeutic agents is also explored.
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Affiliation(s)
- Vincent Murray
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Jon K Chen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Long H Chung
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
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33
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Guo JD, Zhao X, Li Y, Li GR, Liu XL. Damage to dopaminergic neurons by oxidative stress in Parkinson's disease (Review). Int J Mol Med 2018; 41:1817-1825. [PMID: 29393357 DOI: 10.3892/ijmm.2018.3406] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 12/13/2017] [Indexed: 11/05/2022] Open
Abstract
Oxidative stress is increasingly recognized as a central event contributing to the degeneration of dopaminergic neurons in the pathogenesis of Parkinson's disease (PD). Although reactive oxygen species (ROS) production is implicated as a causative factor in PD, the cellular and molecular mechanisms linking oxidative stress with dopaminergic neuron death are complex and not well characterized. The primary insults cause the greatest production of ROS, which contributes to oxidative damage by attacking all macromolecules, including lipids, proteins and nucleic acids, leading to defects in their physiological function. Consequently, the defects in these macromolecules result in mitochondrial dysfunction and neuroinflammation, which subsequently enhance the production of ROS and ultimately neuronal damage. The interaction between these various mechanisms forms a positive feedback loop that drives the progressive loss of dopaminergic neurons in PD, and oxidative stress‑mediated neuron damage appears to serve a central role in the neurodegenerative process. Thus, understanding the cellular and molecular mechanisms by which oxidative stress contributes to the loss of dopaminergic neurons may provide a promising therapeutic approach in PD treatment.
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Affiliation(s)
- Ji-Dong Guo
- Department of Neurology, The First Affiliated Hospital of Beihua University, Jilin, Jilin 132011, P.R. China
| | - Xin Zhao
- Department of Paediatrics, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Yang Li
- Department of Neurology, The Third Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Guang-Ren Li
- Department of Neurology, The Third Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Xiao-Liang Liu
- Cancer Center, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
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34
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Trasviña-Arenas CH, Cardona-Felix CS, Azuara-Liceaga E, Díaz-Quezada C, Brieba LG. Proliferating cell nuclear antigen restores the enzymatic activity of a DNA ligase I deficient in DNA binding. FEBS Open Bio 2017; 7:659-674. [PMID: 28469979 PMCID: PMC5407892 DOI: 10.1002/2211-5463.12209] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 02/13/2017] [Accepted: 02/16/2017] [Indexed: 11/16/2022] Open
Abstract
Proliferating cell nuclear antigen (PCNA) coordinates multienzymatic reactions by interacting with a variety of protein partners. Family I DNA ligases are multidomain proteins involved in sealing of DNA nicks during Okazaki fragment maturation and DNA repair. The interaction of DNA ligases with the interdomain connector loop (IDCL) of PCNA through its PCNA‐interacting peptide (PIP box) is well studied but the role of the interacting surface between both proteins is not well characterized. In this work, we used a minimal DNA ligase I and two N‐terminal deletions to establish that DNA binding and nick‐sealing stimulation of DNA ligase I by PCNA are not solely dependent on the PIP box–IDCL interaction. We found that a truncated DNA ligase I with a deleted PIP box is stimulated by PCNA. Furthermore, the activity of a DNA ligase defective in DNA binding is rescued upon PCNA addition. As the rate constants for single‐turnover ligation for the full‐length and truncated DNA ligases are not affected by PCNA, our data suggest that PCNA stimulation is achieved by increasing the affinity for nicked DNA substrate and not by increasing catalytic efficiency. Surprisingly C‐terminal mutants of PCNA are not able to stimulate nick‐sealing activity of Entamoeba histolytica DNA ligase I. Our data support the notion that the C‐terminal region of PCNA may be involved in promoting an allosteric transition in E. histolytica DNA ligase I from a spread‐shaped to a ring‐shaped structure. This study suggests that the ring‐shaped PCNA is a binding platform able to stabilize coevolved protein–protein interactions, in this case an interaction with DNA ligase I.
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Affiliation(s)
- Carlos H Trasviña-Arenas
- Laboratorio Nacional de Genómica para la Biodiversidad Centro de Investigación y de Estudios Avanzados Irapuato Guanajuato México
| | - Cesar S Cardona-Felix
- Laboratorio Nacional de Genómica para la Biodiversidad Centro de Investigación y de Estudios Avanzados Irapuato Guanajuato México.,Present address: Centro Interdisciplinario de Ciencias Marinas (CICIMAR-IPN) Av. Instituto Politécnico Nacional. s/n.La Paz Baja California Sur 23096 Mexico.,Present address: Cátedras CONACyT Dirección Adjunta de Desarrollo Científico Consejo Nacional de Ciencia y Tecnología Av. Insurgentes Sur 1582 Ciudad de Mexico 03940 Mexico
| | - Elisa Azuara-Liceaga
- Posgrado en Ciencias Genómicas Universidad Autónoma de la Ciudad de México México
| | - Corina Díaz-Quezada
- Laboratorio Nacional de Genómica para la Biodiversidad Centro de Investigación y de Estudios Avanzados Irapuato Guanajuato México
| | - Luis G Brieba
- Laboratorio Nacional de Genómica para la Biodiversidad Centro de Investigación y de Estudios Avanzados Irapuato Guanajuato México
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Overexpression of PCNA Attenuates Oxidative Stress-Caused Delay of Gap-Filling during Repair of UV-Induced DNA Damage. J Nucleic Acids 2017; 2017:8154646. [PMID: 28116145 PMCID: PMC5237465 DOI: 10.1155/2017/8154646] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/12/2016] [Accepted: 11/15/2016] [Indexed: 01/05/2023] Open
Abstract
UVC irradiation-caused DNA lesions are repaired in mammalian cells solely by nucleotide excision repair (NER), which consists of sequential events including initial damage recognition, dual incision of damage site, gap-filling, and ligation. We have previously shown that gap-filling during the repair of UV-induced DNA lesions may be delayed by a subsequent treatment of oxidants or prooxidants such as hydrogen peroxide, flavonoids, and colcemid. We considered the delay as a result of competition for limiting protein/enzyme factor(s) during repair synthesis between NER and base excision repair (BER) induced by the oxidative chemicals. In this report, using colcemid as oxidative stress inducer, we showed that colcemid-caused delay of gap-filling during the repair of UV-induced DNA lesions was attenuated by overexpression of PCNA but not ligase-I. PCNA knockdown, as expected, delayed the gap-filling of NER but also impaired the repair of oxidative DNA damage. Fen-1 knockdown, however, did not affect the repair of oxidative DNA damage, suggesting repair of oxidative DNA damage is not of long patch BER. Furthermore, overexpression of XRCC1 delayed the gap-filling, and presumably increase of XRCC1 pulls PCNA away from gap-filling of NER for BER, consistent with our hypothesis that delay of gap-filling of NER attributes the competition between NER and BER.
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APE2 Zf-GRF facilitates 3'-5' resection of DNA damage following oxidative stress. Proc Natl Acad Sci U S A 2016; 114:304-309. [PMID: 28028224 DOI: 10.1073/pnas.1610011114] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The Xenopus laevis APE2 (apurinic/apyrimidinic endonuclease 2) nuclease participates in 3'-5' nucleolytic resection of oxidative DNA damage and activation of the ATR-Chk1 DNA damage response (DDR) pathway via ill-defined mechanisms. Here we report that APE2 resection activity is regulated by DNA interactions in its Zf-GRF domain, a region sharing high homology with DDR proteins Topoisomerase 3α (TOP3α) and NEIL3 (Nei-like DNA glycosylase 3), as well as transcription and RNA regulatory proteins, such as TTF2 (transcription termination factor 2), TFIIS, and RPB9. Biochemical and NMR results establish the nucleic acid-binding activity of the Zf-GRF domain. Moreover, an APE2 Zf-GRF X-ray structure and small-angle X-ray scattering analyses show that the Zf-GRF fold is typified by a crescent-shaped ssDNA binding claw that is flexibly appended to an APE2 endonuclease/exonuclease/phosphatase (EEP) catalytic core. Structure-guided Zf-GRF mutations impact APE2 DNA binding and 3'-5' exonuclease processing, and also prevent efficient APE2-dependent RPA recruitment to damaged chromatin and activation of the ATR-Chk1 DDR pathway in response to oxidative stress in Xenopus egg extracts. Collectively, our data unveil the APE2 Zf-GRF domain as a nucleic acid interaction module in the regulation of a key single-strand break resection function of APE2, and also reveal topologic similarity of the Zf-GRF to the zinc ribbon domains of TFIIS and RPB9.
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Li DW, Wang YD, Zhou SY, Sun WP. α-lipoic acid exerts neuroprotective effects on neuronal cells by upregulating the expression of PCNA via the P53 pathway in neurodegenerative conditions. Mol Med Rep 2016; 14:4360-4366. [DOI: 10.3892/mmr.2016.5754] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 08/15/2016] [Indexed: 11/06/2022] Open
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End-processing nucleases and phosphodiesterases: An elite supporting cast for the non-homologous end joining pathway of DNA double-strand break repair. DNA Repair (Amst) 2016; 43:57-68. [PMID: 27262532 DOI: 10.1016/j.dnarep.2016.05.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 05/05/2016] [Indexed: 11/20/2022]
Abstract
Nonhomologous end joining (NHEJ) is an error-prone DNA double-strand break repair pathway that is active throughout the cell cycle. A substantial fraction of NHEJ repair events show deletions and, less often, insertions in the repair joints, suggesting an end-processing step comprising the removal of mismatched or damaged nucleotides by nucleases and other phosphodiesterases, as well as subsequent strand extension by polymerases. A wide range of nucleases, including Artemis, Metnase, APLF, Mre11, CtIP, APE1, APE2 and WRN, are biochemically competent to carry out such double-strand break end processing, and have been implicated in NHEJ by at least circumstantial evidence. Several additional DNA end-specific phosphodiesterases, including TDP1, TDP2 and aprataxin are available to resolve various non-nucleotide moieties at DSB ends. This review summarizes the biochemical specificities of these enzymes and the evidence for their participation in the NHEJ pathway.
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Li DW, Li GR, Zhang BL, Feng JJ, Zhao H. Damage to dopaminergic neurons is mediated by proliferating cell nuclear antigen through the p53 pathway under conditions of oxidative stress in a cell model of Parkinson's disease. Int J Mol Med 2015; 37:429-35. [PMID: 26677001 DOI: 10.3892/ijmm.2015.2430] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 11/30/2015] [Indexed: 11/06/2022] Open
Abstract
Oxidative stress is widely considered as a central event in the pathogenesis of Parkinson's disease (PD). The mechanisms underlying the oxidative damage-mediated loss of dopaminergic neurons in PD are not yet fully understood. Accumulating evidence has indicated that oxidative DNA damage plays a crucial role in programmed neuronal cell death, and is considered to be at least partly responsible for the degeneration of dopaminergic neurons in PD. This process involves a number of signaling cascades and molecular proteins. Proliferating cell nuclear antigen (PCNA) is a pleiotropic protein affecting a wide range of vital cellular processes, including chromatin remodelling, DNA repair and cell cycle control, by interacting with a number of enzymes and regulatory proteins. In the present study, the exposure of PC12 cells to 1-methyl-4-phenylpyridinium (MPP+) led to the loss of cell viability and decreased the expression levels of PCNA in a dose- and time-dependent manner, indicating that this protein may be involved in the neurotoxic actions of MPP+ in dopaminergic neuronal cells. In addition, a significant upregulation in p53 expression was also observed in this cellular model of PD. p53 is an upstream inducer of PCNA and it has been recognized as a key contributor responsible for dopaminergic neuronal cell death in mouse models of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD. This indicates that MPP+-induced oxidative damage is mediated by the downregulation of PCNA through the p53 pathway in a cellular model of PD. Thus, our results may provide some novel insight into the molecular mechanisms responsible for the development of PD and provide new possible therapeutic targets for the treatment of PD.
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Affiliation(s)
- Da-Wei Li
- Neuroscience Research Center, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Guang-Ren Li
- Department of Neurology, The Third Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Bei-Lin Zhang
- Department of Physiology, College of Basic Medical Sciences, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Jing-Jing Feng
- Department of Physiology, College of Basic Medical Sciences, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Hua Zhao
- Neuroscience Research Center, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
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Khanam T, Rai N, Ramachandran R. Mycobacterium tuberculosis class II apurinic/apyrimidinic-endonuclease/3'-5' exonuclease III exhibits DNA regulated modes of interaction with the sliding DNA β-clamp. Mol Microbiol 2015; 98:46-68. [PMID: 26103519 DOI: 10.1111/mmi.13102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2015] [Indexed: 11/30/2022]
Abstract
The class-II AP-endonuclease (XthA) acts on abasic sites of damaged DNA in bacterial base excision repair. We identified that the sliding DNA β-clamp forms in vivo and in vitro complexes with XthA in Mycobacterium tuberculosis. A novel 239 QLRFPKK245 motif in the DNA-binding domain of XthA was found to be important for the interactions. Likewise, the peptide binding-groove (PBG) and the C-terminal of β-clamp located on different domains interact with XthA. The β-clamp-XthA complex can be disrupted by clamp binding peptides and also by a specific bacterial clamp inhibitor that binds at the PBG. We also identified that β-clamp stimulates the activities of XthA primarily by increasing its affinity for the substrate and its processivity. Additionally, loading of the β-clamp onto DNA is required for activity stimulation. A reduction in XthA activity stimulation was observed in the presence of β-clamp binding peptides supporting that direct interactions between the proteins are necessary to cause stimulation. Finally, we found that in the absence of DNA, the PBG located on the second domain of the β-clamp is important for interactions with XthA, while the C-terminal domain predominantly mediates functional interactions in the substrate's presence.
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Affiliation(s)
- Taran Khanam
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, Uttar Pradesh, 226031, India
| | - Niyati Rai
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, Uttar Pradesh, 226031, India
| | - Ravishankar Ramachandran
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, Uttar Pradesh, 226031, India
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Liang R, Shen XL, Zhang B, Li Y, Xu W, Zhao C, Luo Y, Huang K. Apoptosis signal-regulating kinase 1 promotes Ochratoxin A-induced renal cytotoxicity. Sci Rep 2015; 5:8078. [PMID: 25627963 PMCID: PMC5389036 DOI: 10.1038/srep08078] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 01/05/2015] [Indexed: 01/04/2023] Open
Abstract
Oxidative stress and apoptosis are involved in Ochratoxin A (OTA)-induced renal cytotoxicity. Apoptosis signal-regulating kinase 1 (ASK1) is a Mitogen-Activated Protein Kinase Kinase Kinase (MAPKKK, MAP3K) family member that plays an important role in oxidative stress-induced cell apoptosis. In this study, we performed RNA interference of ASK1 in HEK293 cells and employed an iTRAQ-based quantitative proteomics approach to globally investigate the regulatory mechanism of ASK1 in OTA-induced renal cytotoxicity. Our results showed that ASK1 knockdown alleviated OTA-induced ROS generation and Δψm loss and thus desensitized the cells to OTA-induced apoptosis. We identified 33 and 24 differentially expressed proteins upon OTA treatment in scrambled and ASK1 knockdown cells, respectively. Pathway classification and analysis revealed that ASK1 participated in OTA-induced inhibition of mRNA splicing, nucleotide metabolism, the cell cycle, DNA repair, and the activation of lipid metabolism. We concluded that ASK1 plays an essential role in promoting OTA-induced renal cytotoxicity.
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Affiliation(s)
- Rui Liang
- Laboratory of food safety and molecular biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, P.R. China
| | - Xiao Li Shen
- 1] Laboratory of food safety and molecular biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, P.R. China [2] School of Public Health, Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Boyang Zhang
- Laboratory of food safety and molecular biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, P.R. China
| | - Yuzhe Li
- Laboratory of food safety and molecular biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, P.R. China
| | - Wentao Xu
- Laboratory of food safety and molecular biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, P.R. China
| | - Changhui Zhao
- Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA
| | - YunBo Luo
- Laboratory of food safety and molecular biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, P.R. China
| | - Kunlun Huang
- Laboratory of food safety and molecular biology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, P.R. China
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42
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Owens RA, Hammel S, Sheridan KJ, Jones GW, Doyle S. A proteomic approach to investigating gene cluster expression and secondary metabolite functionality in Aspergillus fumigatus. PLoS One 2014; 9:e106942. [PMID: 25198175 PMCID: PMC4157829 DOI: 10.1371/journal.pone.0106942] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 08/11/2014] [Indexed: 11/18/2022] Open
Abstract
A combined proteomics and metabolomics approach was utilised to advance the identification and characterisation of secondary metabolites in Aspergillus fumigatus. Here, implementation of a shotgun proteomic strategy led to the identification of non-redundant mycelial proteins (n = 414) from A. fumigatus including proteins typically under-represented in 2-D proteome maps: proteins with multiple transmembrane regions, hydrophobic proteins and proteins with extremes of molecular mass and pI. Indirect identification of secondary metabolite cluster expression was also achieved, with proteins (n = 18) from LaeA-regulated clusters detected, including GliT encoded within the gliotoxin biosynthetic cluster. Biochemical analysis then revealed that gliotoxin significantly attenuates H2O2-induced oxidative stress in A. fumigatus (p>0.0001), confirming observations from proteomics data. A complementary 2-D/LC-MS/MS approach further elucidated significantly increased abundance (p<0.05) of proliferating cell nuclear antigen (PCNA), NADH-quinone oxidoreductase and the gliotoxin oxidoreductase GliT, along with significantly attenuated abundance (p<0.05) of a heat shock protein, an oxidative stress protein and an autolysis-associated chitinase, when gliotoxin and H2O2 were present, compared to H2O2 alone. Moreover, gliotoxin exposure significantly reduced the abundance of selected proteins (p<0.05) involved in de novo purine biosynthesis. Significantly elevated abundance (p<0.05) of a key enzyme, xanthine-guanine phosphoribosyl transferase Xpt1, utilised in purine salvage, was observed in the presence of H2O2 and gliotoxin. This work provides new insights into the A. fumigatus proteome and experimental strategies, plus mechanistic data pertaining to gliotoxin functionality in the organism.
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Affiliation(s)
- Rebecca A. Owens
- Department of Biology, National University of Ireland Maynooth, Maynooth, Co. Kildare, Ireland
| | - Stephen Hammel
- Department of Biology, National University of Ireland Maynooth, Maynooth, Co. Kildare, Ireland
| | - Kevin J. Sheridan
- Department of Biology, National University of Ireland Maynooth, Maynooth, Co. Kildare, Ireland
| | - Gary W. Jones
- Department of Biology, National University of Ireland Maynooth, Maynooth, Co. Kildare, Ireland
| | - Sean Doyle
- Department of Biology, National University of Ireland Maynooth, Maynooth, Co. Kildare, Ireland
- * E-mail:
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Novel insights into the regulatory architecture of CD4+ T cells in rheumatoid arthritis. PLoS One 2014; 9:e100690. [PMID: 24959711 PMCID: PMC4069080 DOI: 10.1371/journal.pone.0100690] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 05/23/2014] [Indexed: 12/21/2022] Open
Abstract
Rheumatoid arthritis (RA) is the most frequent autoimmune chronic inflammatory disease of the joints and it is characterized by the inflammation of the synovial membrane and the subsequent destruction of the joints. In RA, CD4+ T cells are the main drivers of disease initiation and the perpetuation of the damaging inflammatory process. To date, however, the genetic regulatory mechanisms of CD4+ T cells associated with RA etiology are poorly understood. The genome-wide analysis of expression quantitative trait loci (eQTL) in disease-relevant cell types is a recent genomic integration approach that is providing significant insights into the genetic regulatory mechanisms of many human pathologies. The objective of the present study was to analyze, for the first time, the genome-wide genetic regulatory mechanisms associated with the gene expression of CD4+ T cells in RA. Whole genome gene expression profiling of CD4+ T cells and the genome-wide genotyping (598,258 SNPs) of 29 RA patients with an active disease were performed. In order to avoid the excessive burden of multiple testing associated with genome-wide trans-eQTL analysis, we developed and implemented a novel systems genetics approach. Finally, we compared the genomic regulation pattern of CD4+ T cells in RA with the genomic regulation observed in reference lymphoblastoid cell lines (LCLs). We identified a genome-wide significant cis-eQTL associated with the expression of FAM66C gene (P = 6.51e−9). Using our new systems genetics approach we identified six statistically significant trans-eQTLs associated with the expression of KIAA0101 (P<7.4e−8) and BIRC5 (P = 5.35e−8) genes. Finally, comparing the genomic regulation profiles between RA CD4+ T cells and control LCLs we found 20 genes showing differential regulatory patterns between both cell types. The present genome-wide eQTL analysis has identified new genetic regulatory elements that are key to the activity of CD4+ T cells in RA.
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Guikema JEJ, Linehan EK, Esa N, Tsuchimoto D, Nakabeppu Y, Woodland RT, Schrader CE. Apurinic/apyrimidinic endonuclease 2 regulates the expansion of germinal centers by protecting against activation-induced cytidine deaminase-independent DNA damage in B cells. THE JOURNAL OF IMMUNOLOGY 2014; 193:931-9. [PMID: 24935922 DOI: 10.4049/jimmunol.1400002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Activation-induced cytidine deaminase (AID) initiates a process generating DNA mutations and breaks in germinal center (GC) B cells that are necessary for somatic hypermutation and class-switch recombination. GC B cells can "tolerate" DNA damage while rapidly proliferating because of partial suppression of the DNA damage response by BCL6. In this study, we develop a model to study the response of mouse GC B cells to endogenous DNA damage. We show that the base excision repair protein apurinic/apyrimidinic endonuclease (APE) 2 protects activated B cells from oxidative damage in vitro. APE2-deficient mice have smaller GCs and reduced Ab responses compared with wild-type mice. DNA double-strand breaks are increased in the rapidly dividing GC centroblasts of APE2-deficient mice, which activate a p53-independent cell cycle checkpoint and a p53-dependent apoptotic response. Proliferative and/or oxidative damage and AID-dependent damage are additive stresses that correlate inversely with GC size in wild-type, AID-, and APE2-deficient mice. Excessive double-strand breaks lead to decreased expression of BCL6, which would enable DNA repair pathways but limit GC cell numbers. These results describe a nonredundant role for APE2 in the protection of GC cells from AID-independent damage, and although GC cells uniquely tolerate DNA damage, we find that the DNA damage response can still regulate GC size through pathways that involve p53 and BCL6.
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Affiliation(s)
- Jeroen E J Guikema
- Department of Molecular and Physiological Systems, Immunology and Microbiology Program, University of Massachusetts Medical School, Worcester, MA 01655; Department of Pathology, Academic Medical Center, 1105 AZ, Amsterdam, The Netherlands; and
| | - Erin K Linehan
- Department of Molecular and Physiological Systems, Immunology and Microbiology Program, University of Massachusetts Medical School, Worcester, MA 01655
| | - Nada Esa
- Department of Molecular and Physiological Systems, Immunology and Microbiology Program, University of Massachusetts Medical School, Worcester, MA 01655
| | - Daisuke Tsuchimoto
- Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Yusaku Nakabeppu
- Department of Immunobiology and Neuroscience, Medical Institute of Bioregulation, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan
| | - Robert T Woodland
- Department of Molecular and Physiological Systems, Immunology and Microbiology Program, University of Massachusetts Medical School, Worcester, MA 01655
| | - Carol E Schrader
- Department of Molecular and Physiological Systems, Immunology and Microbiology Program, University of Massachusetts Medical School, Worcester, MA 01655;
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Differential expression of APE1 and APE2 in germinal centers promotes error-prone repair and A:T mutations during somatic hypermutation. Proc Natl Acad Sci U S A 2014; 111:9217-22. [PMID: 24927551 DOI: 10.1073/pnas.1405590111] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Somatic hypermutation (SHM) of antibody variable region genes is initiated in germinal center B cells during an immune response by activation-induced cytidine deaminase (AID), which converts cytosines to uracils. During accurate repair in nonmutating cells, uracil is excised by uracil DNA glycosylase (UNG), leaving abasic sites that are incised by AP endonuclease (APE) to create single-strand breaks, and the correct nucleotide is reinserted by DNA polymerase β. During SHM, for unknown reasons, repair is error prone. There are two APE homologs in mammals and, surprisingly, APE1, in contrast to its high expression in both resting and in vitro-activated splenic B cells, is expressed at very low levels in mouse germinal center B cells where SHM occurs, and APE1 haploinsufficiency has very little effect on SHM. In contrast, the less efficient homolog, APE2, is highly expressed and contributes not only to the frequency of mutations, but also to the generation of mutations at A:T base pair (bp), insertions, and deletions. In the absence of both UNG and APE2, mutations at A:T bp are dramatically reduced. Single-strand breaks generated by APE2 could provide entry points for exonuclease recruited by the mismatch repair proteins Msh2-Msh6, and the known association of APE2 with proliferating cell nuclear antigen could recruit translesion polymerases to create mutations at AID-induced lesions and also at A:T bp. Our data provide new insight into error-prone repair of AID-induced lesions, which we propose is facilitated by down-regulation of APE1 and up-regulation of APE2 expression in germinal center B cells.
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Kovvuru P, Mancilla PE, Shirode AB, Murray TM, Begley TJ, Reliene R. Oral ingestion of silver nanoparticles induces genomic instability and DNA damage in multiple tissues. Nanotoxicology 2014; 9:162-71. [DOI: 10.3109/17435390.2014.902520] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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47
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Yang Q, Ou C, Liu M, Xiao W, Wen C, Sun F. NRAGE promotes cell proliferation by stabilizing PCNA in a ubiquitin-proteasome pathway in esophageal carcinomas. Carcinogenesis 2014; 35:1643-51. [PMID: 24710624 DOI: 10.1093/carcin/bgu084] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Neurotrophin receptor-interacting melanoma antigen-encoding gene homolog (NRAGE) is generally recognized as a tumor suppressor as it induces cell apoptosis and suppresses cell metastasis. However, it has recently been reported that NRAGE is overexpressed in lung cancer, melanoma and colon cancer, implicating a complicated role of NRAGE as we have expected. In the study, we aim to elucidate the functional roles and molecular mechanisms of NRAGE in esophageal carcinoma. We found that both NRAGE mRNA and protein were significantly overexpressed in esophageal tumor tissues. Consistently, both in vivo and in vitro analyses demonstrated that knockdown of NRAGE apparently inhibited cell growth, and cell cycle analysis further demonstrated that NRAGE knockdown cells were mainly arrested in G2M cell phase, accompanied with an apparent reduction of S phase. In the process of exploring molecular mechanisms, we found that either knockdown in vitro or knockout in vivo of NRAGE reduced proliferating cell nuclear antigen (PCNA) protein, expression of which could completely rescue the inhibited proliferation in NRAGE defective cells. Furthermore, NRAGE physically interacted with PCNA in esophageal cancer cells through DNA polymerase III subunit, and knockdown of NRAGE facilitated PCNA K48-linked polyubiquitination, leading PCNA to the proteasome-dependent degradation and a ubiquitin-specific protease USP10 was identified to be a key regulator in the process of K48 polyubiquitination in NRAGE-deleted cells. In conclusion, our study highlights a unique role of NRAGE and implies that NRAGE is likely to be an attractive oncotarget in developing novel genetic anticancer therapeutic strategies for esophageal squamous cell carcinomas.
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Affiliation(s)
- Qingyuan Yang
- Department of Clinical Laboratory Medicine, Tenth People's Hospital of Tongji University, Shanghai 200072, China, Department of Clinical Laboratory, The Affiliated Tumor Hospital of Guangxi Medical University, Nanning 530021, China, Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing 210023, China and The Central Laboratory, Tenth People's Hospital of Tongji University, Shanghai 200072, China
| | - Chao Ou
- Department of Clinical Laboratory, The Affiliated Tumor Hospital of Guangxi Medical University, Nanning 530021, China
| | - Mei Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing 210023, China and
| | - Weifan Xiao
- The Central Laboratory, Tenth People's Hospital of Tongji University, Shanghai 200072, China
| | - Chuanjun Wen
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing 210023, China and
| | - Fenyong Sun
- Department of Clinical Laboratory Medicine, Tenth People's Hospital of Tongji University, Shanghai 200072, China, Department of Clinical Laboratory, The Affiliated Tumor Hospital of Guangxi Medical University, Nanning 530021, China, Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing 210023, China and The Central Laboratory, Tenth People's Hospital of Tongji University, Shanghai 200072, China
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Jin J, Hwang BJ, Chang PW, Toth EA, Lu AL. Interaction of apurinic/apyrimidinic endonuclease 2 (Apn2) with Myh1 DNA glycosylase in fission yeast. DNA Repair (Amst) 2014; 15:1-10. [PMID: 24559510 PMCID: PMC3967872 DOI: 10.1016/j.dnarep.2014.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 12/27/2013] [Accepted: 01/06/2014] [Indexed: 12/29/2022]
Abstract
Oxidative DNA damage is repaired primarily by the base excision repair (BER) pathway in a process initiated by removal of base lesions or mismatched bases by DNA glycosylases. MutY homolog (MYH, MUTYH, or Myh1) is a DNA glycosylase which excises adenine paired with the oxidative lesion 8-oxo-7,8-dihydroguanine (8-oxoG, or G°), thus reducing G:C to T:A mutations. The resulting apurinic/apyrimidinic (AP) site is processed by an AP-endonuclease or a bifunctional glycosylase/lyase. We show here that the major Schizosaccharomyces pombe AP endonuclease, Apn2, binds to the inter-domain connector located between the N- and C-terminal domains of Myh1. This Myh1 inter-domain connector also interacts with the Hus1 subunit of the Rad9-Rad1-Hus1 checkpoint clamp. Mutagenesis studies indicate that Apn2 and Hus1 bind overlapping but different sequence motifs on Myh1. Mutation on I(261) of Myh1 reduces its interaction with Hus1, but only slightly attenuates its interaction with Apn2. However, E(262) of Myh1 is a key determinant for both Apn2 and Hus1 interactions. Like human APE1, Apn2 has 3'-phosphodiesterase activity. However, unlike hAPE1, Apn2 has a weak AP endonuclease activity which cleaves the AP sites generated by Myh1 glycosylase. Functionally, Apn2 stimulates Myh1 glycosylase activity and Apn2 phosphodiesterase activity is stimulated by Myh1. The cross stimulation of Myh1 and Apn2 enzymatic activities is dependent on their physical interaction. Thus, Myh1 and Apn2 constitute an initial BER complex.
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Affiliation(s)
- Jin Jin
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Bor-Jang Hwang
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Po-Wen Chang
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Eric A Toth
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Center for Biomolecular Therapeutics, University of Maryland School of Medicine, Rockville, MD 20850, USA
| | - A-Lien Lu
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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Abstract
SIGNIFICANCE Human apurinic/apyrimidinic endonuclease 1 (APE1, also known as REF-1) was isolated based on its ability to cleave at AP sites in DNA or activate the DNA binding activity of certain transcription factors. We review herein topics related to this multi-functional DNA repair and stress-response protein. RECENT ADVANCES APE1 displays homology to Escherichia coli exonuclease III and is a member of the divalent metal-dependent α/β fold-containing phosphoesterase superfamily of enzymes. APE1 has acquired distinct active site and loop elements that dictate substrate selectivity, and a unique N-terminus which at minimum imparts nuclear targeting and interaction specificity. Additional activities ascribed to APE1 include 3'-5' exonuclease, 3'-repair diesterase, nucleotide incision repair, damaged or site-specific RNA cleavage, and multiple transcription regulatory roles. CRITICAL ISSUES APE1 is essential for mouse embryogenesis and contributes to cell viability in a genetic background-dependent manner. Haploinsufficient APE1(+/-) mice exhibit reduced survival, increased cancer formation, and cellular/tissue hyper-sensitivity to oxidative stress, supporting the notion that impaired APE1 function associates with disease susceptibility. Although abnormal APE1 expression/localization has been seen in cancer and neuropathologies, and impaired-function variants have been described, a causal link between an APE1 defect and human disease remains elusive. FUTURE DIRECTIONS Ongoing efforts aim at delineating the biological role(s) of the different APE1 activities, as well as the regulatory mechanisms for its intra-cellular distribution and participation in diverse molecular pathways. The determination of whether APE1 defects contribute to human disease, particularly pathologies that involve oxidative stress, and whether APE1 small-molecule regulators have clinical utility, is central to future investigations.
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Affiliation(s)
- Mengxia Li
- Intramural Research Program, Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health , Baltimore, Maryland
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Scott TL, Rangaswamy S, Wicker CA, Izumi T. Repair of oxidative DNA damage and cancer: recent progress in DNA base excision repair. Antioxid Redox Signal 2014; 20:708-26. [PMID: 23901781 PMCID: PMC3960848 DOI: 10.1089/ars.2013.5529] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
SIGNIFICANCE Reactive oxygen species (ROS) are generated by exogenous and environmental genotoxins, but also arise from mitochondria as byproducts of respiration in the body. ROS generate DNA damage of which pathological consequence, including cancer is well established. Research efforts are intense to understand the mechanism of DNA base excision repair, the primary mechanism to protect cells from genotoxicity caused by ROS. RECENT ADVANCES In addition to the notion that oxidative DNA damage causes transformation of cells, recent studies have revealed how the mitochondrial deficiencies and ROS generation alter cell growth during the cancer transformation. CRITICAL ISSUES The emphasis of this review is to highlight the importance of the cellular response to oxidative DNA damage during carcinogenesis. Oxidative DNA damage, including 7,8-dihydro-8-oxoguanine, play an important role during the cellular transformation. It is also becoming apparent that the unusual activity and subcellular distribution of apurinic/apyrimidinic endonuclease 1, an essential DNA repair factor/redox sensor, affect cancer malignancy by increasing cellular resistance to oxidative stress and by positively influencing cell proliferation. FUTURE DIRECTIONS Technological advancement in cancer cell biology and genetics has enabled us to monitor the detailed DNA repair activities in the microenvironment. Precise understanding of the intracellular activities of DNA repair proteins for oxidative DNA damage should provide help in understanding how mitochondria, ROS, DNA damage, and repair influence cancer transformation.
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Affiliation(s)
- Timothy L Scott
- Graduate Center for Toxicology, University of Kentucky , Lexington, Kentucky
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