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Młotkowska P, Misztal T, Kowalczyk P, Marciniak E. Effect of kynurenic acid on enzymatic activity of the DNA base excision repair pathway in specific areas of the sheep brain. Sci Rep 2024; 14:15506. [PMID: 38969725 PMCID: PMC11226655 DOI: 10.1038/s41598-024-66094-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 06/27/2024] [Indexed: 07/07/2024] Open
Abstract
Relatively low levels of antioxidant enzymes coupled with high oxygen metabolism result in the formation of numerous oxidative DNA damages in the tissues of the central nervous system. Recently, kynurenic acid (KYNA), knowns for its neuroprotective properties, has gained increasing attention in this context. Therefore, our hypothesis assumed that increased KYNA levels in the brain would positively influence mRNA expression of selected enzymes of the base excision repair pathway as well as enhance their efficiency in excising damaged nucleobases in specific areas of the sheep brain. The study was conducted on adult anestrous sheep (n = 18), in which two different doses of KYNA (20 and 100 μg/day) were infused into the third brain ventricle for three days. Molecular and biochemical analysis included the hypothalamus (preoptic and mediol-basal areas), hippocampus (CA3 field) and amygdala (central amygdaloid nucleus), dissected from the brain of sheep euthanized immediately after the last infusion. The results revealed a significant increase P < 0.001) in the relative mRNA abundance of N-methylpurine DNA glycosylase (MPG) following administration of both dose of KYNA across all examined tissues. The transcription of thymine-DNA glycosylase (TDG) increased significantly (P < 0.001) in all tissues in response to the lower KYNA dose compared to the control group. Moreover, 8-oxoguanine (8-oxoG) DNA glycosylase (OGG1) mRNA levels were also higher in both animal groups (P < 0.001). In addition, in the hypothalamus, hippocampus and amygdala, AP endonuclease 1 (APE1) mRNA expression increased under both doses of KYNA. Moreover, the both dose of KYNA significantly stimulated the efficiency of 8-oxoG excision in hypothalamus and amygdala (P < 0.05-0.001). The lower and higher doses of KYNA significantly influenced the effectiveness of εA and εC in all structures (P < 0.01-0.001). In conclusion, the favorable effect of KYNA in the brain may include the protection of genetic material in nerve and glial cells by stimulating the expression and efficiency of BER pathway enzymes.
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Affiliation(s)
- Patrycja Młotkowska
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3 Str., 05-110, Jabłonna, Poland.
| | - Tomasz Misztal
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3 Str., 05-110, Jabłonna, Poland
| | - Paweł Kowalczyk
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3 Str., 05-110, Jabłonna, Poland
| | - Elżbieta Marciniak
- Department of Animal Physiology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Instytucka 3 Str., 05-110, Jabłonna, Poland
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Linowiecka K, Guz J, Dziaman T, Urbanowska-Domańska O, Zarakowska E, Szpila A, Szpotan J, Skalska-Bugała A, Mijewski P, Siomek-Górecka A, Różalski R, Gackowski D, Oliński R, Foksiński M. The level of active DNA demethylation compounds in leukocytes and urine samples as potential epigenetic biomarkers in breast cancer patients. Sci Rep 2024; 14:6481. [PMID: 38499584 PMCID: PMC10948817 DOI: 10.1038/s41598-024-56326-5] [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: 08/07/2023] [Accepted: 03/05/2024] [Indexed: 03/20/2024] Open
Abstract
The active DNA demethylation process, which involves TET proteins, can affect DNA methylation pattern. TET dependent demethylation results in DNA hypomethylation by oxidation 5-methylcytosine (5-mC) to 5-hydroxymethylcytosine (5-hmC) and its derivatives. Moreover, TETs' activity may be upregulated by ascorbate. Given that aberrant DNA methylation of genes implicated in breast carcinogenesis may be involved in tumor progression, we wanted to determine whether breast cancer patients exert changes in the active DNA demethylation process. The study included blood samples from breast cancer patients (n = 74) and healthy subjects (n = 71). We analyzed the expression of genes involved in the active demethylation process (qRT-PCR), and 5-mC and its derivatives level (2D-UPLC MS/MS). The ascorbate level was determined using UPLC-MS. Breast cancer patients had significantly higher TET3 expression level, lower 5-mC and 5-hmC DNA levels. TET3 was significantly increased in luminal B breast cancer patients with expression of hormone receptors. Moreover, the ascorbate level in the plasma of breast cancer patients was decreased with the accompanying increase of sodium-dependent vitamin C transporters (SLC23A1 and SLC23A2). The presented study indicates the role of TET3 in DNA demethylation in breast carcinogenesis.
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Affiliation(s)
- Kinga Linowiecka
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85‑092, Bydgoszcz, Poland.
- Department of Human Biology, Institute of Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100, Toruń, Poland.
| | - Jolanta Guz
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85‑092, Bydgoszcz, Poland
| | - Tomasz Dziaman
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85‑092, Bydgoszcz, Poland
| | - Olga Urbanowska-Domańska
- Department of Oncology, Professor Franciszek Lukaszczyk Oncology Centre, Romanowskiej 2, 85-796, Bydgoszcz, Poland
| | - Ewelina Zarakowska
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85‑092, Bydgoszcz, Poland
| | - Anna Szpila
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85‑092, Bydgoszcz, Poland
| | - Justyna Szpotan
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85‑092, Bydgoszcz, Poland
- Department of Human Biology, Institute of Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100, Toruń, Poland
| | - Aleksandra Skalska-Bugała
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85‑092, Bydgoszcz, Poland
| | - Paweł Mijewski
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85‑092, Bydgoszcz, Poland
| | - Agnieszka Siomek-Górecka
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85‑092, Bydgoszcz, Poland
| | - Rafał Różalski
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85‑092, Bydgoszcz, Poland
| | - Daniel Gackowski
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85‑092, Bydgoszcz, Poland
| | - Ryszard Oliński
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85‑092, Bydgoszcz, Poland
| | - Marek Foksiński
- Department of Clinical Biochemistry, Faculty of Pharmacy, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Karlowicza 24, 85‑092, Bydgoszcz, Poland.
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3
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Fischer V, Kretschmer M, Germain PL, Kaur J, Mompart-Barrenechea S, Pelczar P, Schürmann D, Schär P, Gapp K. Sperm chromatin accessibility's involvement in the intergenerational effects of stress hormone receptor activation. Transl Psychiatry 2023; 13:378. [PMID: 38065942 PMCID: PMC10709351 DOI: 10.1038/s41398-023-02684-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Dexamethasone is a stress hormone receptor agonist used widely in clinics. We and others previously showed that paternal administration of dexamethasone in mice affects the phenotype of their offspring. The substrate of intergenerational transmission of environmentally induced effects often involves changes in sperm RNA, yet other epigenetic modifications in the germline can be affected and are also plausible candidates. First, we tested the involvement of altered sperm RNAs in the transmission of dexamethasone induced phenotypes across generations. We did this by injecting sperm RNA into naïve fertilized oocytes, before performing metabolic and behavioral phenotyping of the offspring. We observed phenotypic changes in discordance with those found in offspring generated by in vitro fertilization using sperm from dexamethasone exposed males. Second, we investigated the effect of dexamethasone on chromatin accessibility using ATAC sequencing and found significant changes at specific genomic features and gene regulatory loci. Employing q-RT-PCR, we show altered expression of a gene in the tissue of offspring affected by accessibility changes in sperm. Third, we establish a correlation between specific DNA modifications and stress hormone receptor activity as a likely contributing factor influencing sperm accessibility. Finally, we independently investigated this dependency by genetically reducing thymine-DNA glycosylase levels and observing concomitant changes at the level of chromatin accessibility and stress hormone receptor activity.
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Affiliation(s)
- Vincent Fischer
- Laboratory of Epigenetics and Neuroendocrinology, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
- Neuroscience Center Zurich, ETH Zürich and University of Zürich, Zürich, Switzerland
| | - Miriam Kretschmer
- Laboratory of Epigenetics and Neuroendocrinology, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
- Neuroscience Center Zurich, ETH Zürich and University of Zürich, Zürich, Switzerland
| | - Pierre-Luc Germain
- Laboratory of Epigenetics and Neuroendocrinology, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
- Laboratory of Molecular and Behavioral Neuroscience, Institute for Neuroscience, Department of Health Science and Technology, Zürich, Switzerland
- Computational Neurogenomics, Institute for Neuroscience, Department of Health Science and Technology, Zürich, Switzerland
- Laboratory of Statistical Bioinformatics, University of Zürich, Zürich, Switzerland
| | - Jasmine Kaur
- Laboratory of Epigenetics and Neuroendocrinology, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Sergio Mompart-Barrenechea
- Laboratory of Epigenetics and Neuroendocrinology, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Pawel Pelczar
- Center for Transgenic Models, University of Basel, Basel, Switzerland
| | - David Schürmann
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Primo Schär
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Katharina Gapp
- Laboratory of Epigenetics and Neuroendocrinology, Institute for Neuroscience, Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland.
- Neuroscience Center Zurich, ETH Zürich and University of Zürich, Zürich, Switzerland.
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4
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Aranda S, Alcaine-Colet A, Ballaré C, Blanco E, Mocavini I, Sparavier A, Vizán P, Borràs E, Sabidó E, Di Croce L. Thymine DNA glycosylase regulates cell-cycle-driven p53 transcriptional control in pluripotent cells. Mol Cell 2023:S1097-2765(23)00517-8. [PMID: 37506700 DOI: 10.1016/j.molcel.2023.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/11/2023] [Accepted: 07/05/2023] [Indexed: 07/30/2023]
Abstract
Cell cycle progression is linked to transcriptome dynamics and variations in the response of pluripotent cells to differentiation cues, mostly through unknown determinants. Here, we characterized the cell-cycle-associated transcriptome and proteome of mouse embryonic stem cells (mESCs) in naive ground state. We found that the thymine DNA glycosylase (TDG) is a cell-cycle-regulated co-factor of the tumor suppressor p53. Furthermore, TDG and p53 co-bind ESC-specific cis-regulatory elements and thereby control transcription of p53-dependent genes during self-renewal. We determined that the dynamic expression of TDG is required to promote the cell-cycle-associated transcriptional heterogeneity. Moreover, we demonstrated that transient depletion of TDG influences cell fate decisions during the early differentiation of mESCs. Our findings reveal an unanticipated role of TDG in promoting molecular heterogeneity during the cell cycle and highlight the central role of protein dynamics for the temporal control of cell fate during development.
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Affiliation(s)
- Sergi Aranda
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain.
| | - Anna Alcaine-Colet
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Cecilia Ballaré
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Enrique Blanco
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | - Ivano Mocavini
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
| | | | - Pedro Vizán
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain; Blanquerna School of Health Science, Universitat Ramon Llull, Barcelona 08025, Spain
| | - Eva Borràs
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Eduard Sabidó
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Luciano Di Croce
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; ICREA, Pg. Lluis Companys 23, Barcelona 08010, Spain.
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5
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Lirussi L, Nilsen HL. DNA Glycosylases Define the Outcome of Endogenous Base Modifications. Int J Mol Sci 2023; 24:10307. [PMID: 37373453 DOI: 10.3390/ijms241210307] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/13/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
Chemically modified nucleic acid bases are sources of genomic instability and mutations but may also regulate gene expression as epigenetic or epitranscriptomic modifications. Depending on the cellular context, they can have vastly diverse impacts on cells, from mutagenesis or cytotoxicity to changing cell fate by regulating chromatin organisation and gene expression. Identical chemical modifications exerting different functions pose a challenge for the cell's DNA repair machinery, as it needs to accurately distinguish between epigenetic marks and DNA damage to ensure proper repair and maintenance of (epi)genomic integrity. The specificity and selectivity of the recognition of these modified bases relies on DNA glycosylases, which acts as DNA damage, or more correctly, as modified bases sensors for the base excision repair (BER) pathway. Here, we will illustrate this duality by summarizing the role of uracil-DNA glycosylases, with particular attention to SMUG1, in the regulation of the epigenetic landscape as active regulators of gene expression and chromatin remodelling. We will also describe how epigenetic marks, with a special focus on 5-hydroxymethyluracil, can affect the damage susceptibility of nucleic acids and conversely how DNA damage can induce changes in the epigenetic landscape by altering the pattern of DNA methylation and chromatin structure.
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Affiliation(s)
- Lisa Lirussi
- Department of Clinical Molecular Biology, Institute of Clinical Medicine, University of Oslo, 0318 Oslo, Norway
- Section of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478 Lørenskog, Norway
- Department of Microbiology, Oslo University Hospital, 0424 Oslo, Norway
| | - Hilde Loge Nilsen
- Department of Clinical Molecular Biology, Institute of Clinical Medicine, University of Oslo, 0318 Oslo, Norway
- Department of Microbiology, Oslo University Hospital, 0424 Oslo, Norway
- Unit for Precision Medicine, Akershus University Hospital, 1478 Lørenskog, Norway
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6
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Egiazarian MA, Strømstad S, Sakshaug T, Nunez-Nescolarde AB, Bethge N, Bjørås M, Scheffler K. Age- and sex-dependent effects of DNA glycosylase Neil3 on amyloid pathology, adult neurogenesis, and memory in a mouse model of Alzheimer's disease. Free Radic Biol Med 2022; 193:685-693. [PMID: 36395955 DOI: 10.1016/j.freeradbiomed.2022.11.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 10/21/2022] [Accepted: 11/12/2022] [Indexed: 11/16/2022]
Abstract
Oxidative stress generating DNA damage has been shown to be a key characteristic in Alzheimer's disease (AD). However, how it affects the pathogenesis of AD is not yet fully understood. Neil3 is a DNA glycosylase initiating repair of oxidative DNA base lesions and with a distinct expression pattern in proliferating cells. In brain, its function has been linked to hippocampal-dependent memory and to induction of neurogenesis after stroke and in prion disease. Here, we generated a novel AD mouse model deficient for Neil3 to study the impact of impaired oxidative base lesion repair on the pathogenesis of AD. Our results demonstrate an age-dependent decrease in amyloid-β (Aβ) plaque deposition in female Neil3-deficient AD mice, whereas no significant difference was observed in male mice. Furthermore, male but not female Neil3-deficient AD mice show reduced neural stem cell proliferation in the adult hippocampus and impaired working memory compared to controls. These effects seem to be independent of DNA repair as both sexes show increased level of oxidative base lesions in the hippocampus upon loss of Neil3. Thus, our findings suggest an age- and sex-dependent role of Neil3 in the progression of AD by altering cerebral Aβ accumulation and promoting adult hippocampal neurogenesis to maintain cognitive function.
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Affiliation(s)
- Milena A Egiazarian
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Silje Strømstad
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Teri Sakshaug
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Ana B Nunez-Nescolarde
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Nicole Bethge
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Magnar Bjørås
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Department of Microbiology, Oslo University Hospital HF, Rikshospitalet and University of Oslo, Oslo, Norway
| | - Katja Scheffler
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Department of Neurology and Clinical Neurophysiology, University Hospital Trondheim, Trondheim, Norway.
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7
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Tarantino ME, Delaney S. Kinetic Analysis of the Effect of N-Terminal Acetylation on Thymine DNA Glycosylase. Biochemistry 2022; 61:895-908. [PMID: 35436101 PMCID: PMC9117521 DOI: 10.1021/acs.biochem.1c00823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Thymine DNA glycosylase (TDG) is tasked with initiating DNA base excision repair by recognizing and removing T, U, the chemotherapeutic 5-fluorouracil (5-FU), and many other oxidized and halogenated pyrimidine bases. TDG contains a long, unstructured N-terminus that contains four known sites of acetylation: lysine (K) residues 59, 83, 84, and 87. Here, K to glutamine (Q) mutants are used as acetyl-lysine (AcK) analogues to probe the effect of N-terminal acetylation on the kinetics of TDG. We find that mimicking acetylation affects neither the maximal single-turnover rate kmax nor the turnover rate kTO, indicating that the steps after initial binding, through chemistry and product release, are not affected. Under subsaturating conditions, however, acetylation changes the processing of U substrates. Subtle differences among AcK analogues are revealed with 5-FU in single-stranded DNA. We propose that the subtleties observed among the AcK analogues may be amplified on the genomic scale, leading to regulation of TDG activity. N-terminal acetylation, though, may also play a structural, rather than kinetic role in vivo.
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Affiliation(s)
- Mary E. Tarantino
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, United States
| | - Sarah Delaney
- Department of Chemistry, Brown University, Providence, RI 02912, United States
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8
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The Role of Thymine DNA Glycosylase in Transcription, Active DNA Demethylation, and Cancer. Cancers (Basel) 2022; 14:cancers14030765. [PMID: 35159032 PMCID: PMC8833622 DOI: 10.3390/cancers14030765] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/28/2022] [Accepted: 01/28/2022] [Indexed: 02/04/2023] Open
Abstract
Simple Summary Thymine DNA Glycosylase (TDG) is a DNA repair protein that plays an important role in gene regulation. Recent studies have shown that TDG interacts with various transcription factors to activate target genes. TDG also functions in a pathway known as active DNA demethylation, which removes 5-mC from DNA and replaces it with unmethylated cytosine. In this review, we summarize the various functions of TDG in gene regulation as well as the physiological relevance of TDG in cancer. Abstract DNA methylation is an essential covalent modification that is required for growth and development. Once considered to be a relatively stable epigenetic mark, many studies have established that DNA methylation is dynamic. The 5-methylcytosine (5-mC) mark can be removed through active DNA demethylation in which 5-mC is converted to an unmodified cytosine through an oxidative pathway coupled to base excision repair (BER). The BER enzyme Thymine DNA Glycosylase (TDG) plays a key role in active DNA demethylation by excising intermediates of 5-mC generated by this process. TDG acts as a key player in transcriptional regulation through its interactions with various nuclear receptors and transcription factors, in addition to its involvement in classical BER and active DNA demethylation, which serve to protect the stability of the genome and epigenome, respectively. Recent animal studies have identified a connection between the loss of Tdg and the onset of tumorigenesis. In this review, we summarize the recent findings on TDG’s function as a transcriptional regulator as well as the physiological relevance of TDG and active DNA demethylation in cancer.
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9
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Roles of enhancer RNAs in sex hormone-dependent cancers. J Cancer Res Clin Oncol 2022; 148:293-307. [DOI: 10.1007/s00432-021-03886-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 12/13/2021] [Indexed: 12/24/2022]
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10
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Bordin DL, Lirussi L, Nilsen H. Cellular response to endogenous DNA damage: DNA base modifications in gene expression regulation. DNA Repair (Amst) 2021; 99:103051. [PMID: 33540225 DOI: 10.1016/j.dnarep.2021.103051] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/15/2021] [Accepted: 01/18/2021] [Indexed: 12/19/2022]
Abstract
The integrity of the genetic information is continuously challenged by numerous genotoxic insults, most frequently in the form of oxidation, alkylation or deamination of the bases that result in DNA damage. These damages compromise the fidelity of the replication, and interfere with the progression and function of the transcription machineries. The DNA damage response (DDR) comprises a series of strategies to deal with DNA damage, including transient transcriptional inhibition, activation of DNA repair pathways and chromatin remodeling. Coordinated control of transcription and DNA repair is required to safeguardi cellular functions and identities. Here, we address the cellular responses to endogenous DNA damage, with a particular focus on the role of DNA glycosylases and the Base Excision Repair (BER) pathway, in conjunction with the DDR factors, in responding to DNA damage during the transcription process. We will also discuss functions of newly identified epigenetic and regulatory marks, such as 5-hydroxymethylcytosine and its oxidative products and 8-oxoguanine, that were previously considered only as DNA damages. In light of these resultsthe classical perception of DNA damage as detrimental for cellular processes are changing. and a picture emerges whereDNA glycosylases act as dynamic regulators of transcription, placing them at the intersection of DNA repair and gene expression modulation.
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Affiliation(s)
- Diana L Bordin
- Department of Clinical Molecular Biology, University of Oslo, 0318, Oslo, Norway; Department of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478, Lørenskog, Norway
| | - Lisa Lirussi
- Department of Clinical Molecular Biology, University of Oslo, 0318, Oslo, Norway; Department of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478, Lørenskog, Norway
| | - Hilde Nilsen
- Department of Clinical Molecular Biology, University of Oslo, 0318, Oslo, Norway; Department of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478, Lørenskog, Norway.
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11
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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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12
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Reading Targeted DNA Damage in the Active Demethylation Pathway: Role of Accessory Domains of Eukaryotic AP Endonucleases and Thymine-DNA Glycosylases. J Mol Biol 2020:S0022-2836(19)30720-X. [DOI: 10.1016/j.jmb.2019.12.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/24/2019] [Accepted: 12/05/2019] [Indexed: 01/07/2023]
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13
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Koliadenko V, Wilanowski T. Additional functions of selected proteins involved in DNA repair. Free Radic Biol Med 2020; 146:1-15. [PMID: 31639437 DOI: 10.1016/j.freeradbiomed.2019.10.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/16/2019] [Accepted: 10/16/2019] [Indexed: 12/30/2022]
Abstract
Protein moonlighting is a phenomenon in which a single polypeptide chain can perform a number of different unrelated functions. Here we present our analysis of moonlighting in the case of selected DNA repair proteins which include G:T mismatch-specific thymine DNA glycosylase (TDG), methyl-CpG-binding domain protein 4 (MBD4), apurinic/apyrimidinic endonuclease 1 (APE1), AlkB homologs, poly (ADP-ribose) polymerase 1 (PARP-1) and single-strand selective monofunctional uracil DNA glycosylase 1 (SMUG1). Most of their additional functions are not accidental and clear patterns are emerging. Participation in RNA metabolism is not surprising as bases occurring in RNA are the same or very similar to those in DNA. Other common additional function involves regulation of transcription. This is not unexpected as these proteins bind to specific DNA regions for DNA repair, hence they can also be recruited to regulate transcription. Participation in demethylation and replication of DNA appears logical as well. Some of the multifunctional DNA repair proteins play major roles in many diseases, including cancer. However, their moonlighting might prove a major difficulty in the development of new therapies because it will not be trivial to target a single protein function without affecting its other functions that are not related to the disease.
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Affiliation(s)
- Vlada Koliadenko
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Ilji Miecznikowa 1, 02-096, Warsaw, Poland
| | - Tomasz Wilanowski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Ilji Miecznikowa 1, 02-096, Warsaw, Poland.
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14
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Ni F, Tang H, Wang C, Wang Z, Yu F, Chen B, Sun L. Berzosertib (VE-822) inhibits gastric cancer cell proliferation via base excision repair system. Cancer Manag Res 2019; 11:8391-8405. [PMID: 31571995 PMCID: PMC6750847 DOI: 10.2147/cmar.s217375] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 09/03/2019] [Indexed: 12/15/2022] Open
Abstract
Background Current investigations suggest that the Base Excision Repair (BER) system may change DNA repair capacity and affect clinical gastric cancer progression such as overall survival. However, the prognostic value of BER system members in gastric cancer remains unclear. Methods We explored the prognostic correlation between 7 individual BER genes, including uracil-DNA glycosylase (UNG), Single-strand-selective monofunctional uracil-DNA glycosylase 1 (SMUG1), Methyl-CpG binding domain 4 (MBD4), thymine DNA glycosylase (TDG), 8-oxoguanine DNA glycosylase (OGG1), MutY DNA glycosylase (MUTYH) and Nei like DNA glycosylase 1 (NEIL1), expression and overall survival (OS) in different clinical data, such as Lauren classification, pathological stages, human epidermal growth factor receptor-2 (HER2) expression status, treatment strategy, gender and differentiation degree in gastric cancer patients, using Kaplan-Meier plotter (KM plotter) online database. Based on the bioinformatics analysis, we utilized Berzosertib (VE-822) to inhibit DNA damage repair in cancer cells compared to solvent control group via real-time cellular analysis (RTCA), flow cytometry, colony formation and migration assay. Finally, we utilized reverse transcription-polymerase chain reaction (RT-PCR) to confirm the expression of BER members between normal and two gastric cancer cells or solvent and VE-822 treated groups. Results Our work revealed that high UNG mRNA expression was correlated with high overall survival probability; however, high SMUG1, MBD4, TDG, OGG1, MUTYH and NEIL1 mRNA expression showed relatively low overall survival probability in all GC patients. Additionally, UNG was associated with high overall survival probability in intestinal and diffuse types, but SMUG1 and NEIL1 showed opposite results. Further, VE-822 pharmacological experiment suggested that inhibition of DNA damage repair suppressed gastric cancer cells’ proliferation and migration ability via inducing apoptosis. Further, real-time polymerase chain reaction results proposed the inhibition of gastric cancer cells by VE-822 may be through UNG, MUTYH and OGG-1 of BER system. Conclusion We comprehensively analyze the prognostic value of the BER system (UNG, SMUG1, MBD4, TDG, OGG1, MUTYH and NEIL1) based on bioinformatics analysis and experimental confirmation. BER members are associated with distinctive prognostic significance and maybe new valuable prognostic indicators in gastric cancer.
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Affiliation(s)
- Fubiao Ni
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Zhejiang Provincial Top Key Discipline in Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People's Republic of China
| | - Hengjie Tang
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Zhejiang Provincial Top Key Discipline in Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People's Republic of China
| | - Cheng Wang
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Zhejiang Provincial Top Key Discipline in Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People's Republic of China
| | - Zixiang Wang
- First College of Clinical Medicine, Wenzhou Medical University, Wenzhou, Zhejiang, People's Republic of China
| | - Fangyi Yu
- First College of Clinical Medicine, Wenzhou Medical University, Wenzhou, Zhejiang, People's Republic of China
| | - Bicheng Chen
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Zhejiang Provincial Top Key Discipline in Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People's Republic of China
| | - Linxiao Sun
- Key Laboratory of Diagnosis and Treatment of Severe Hepato-Pancreatic Diseases of Zhejiang Province, Zhejiang Provincial Top Key Discipline in Surgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, People's Republic of China
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15
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Coey CT, Drohat AC. Defining the impact of sumoylation on substrate binding and catalysis by thymine DNA glycosylase. Nucleic Acids Res 2019; 46:5159-5170. [PMID: 29660017 PMCID: PMC6007377 DOI: 10.1093/nar/gky278] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 04/04/2018] [Indexed: 01/22/2023] Open
Abstract
Thymine DNA glycosylase (TDG) excises thymine from mutagenic G·T mispairs generated by deamination of 5-methylcytosine (mC) and it removes two mC derivatives, 5−formylcytosine (fC) and 5−carboxylcytosine (caC), in a multistep pathway for DNA demethylation. TDG is modified by small ubiquitin-like modifier (SUMO) proteins, but the impact of sumoylation on TDG activity is poorly defined and the functions of TDG sumoylation remain unclear. We determined the effect of TDG sumoylation, by SUMO-1 or SUMO-2, on substrate binding and catalytic parameters. Single turnover experiments reveal that sumoylation dramatically impairs TDG base-excision activity, such that G·T activity is reduced by ≥45-fold and fC and caC are excised slowly, with a reaction half-life of ≥9 min (37°C). Fluorescence anisotropy studies reveal that unmodified TDG binds tightly to G·fC and G·caC substrates, with dissociation constants in the low nanomolar range. While sumoylation of TDG weakens substrate binding, the residual affinity is substantial and is comparable to that of biochemically-characterized readers of fC and caC. Our findings raise the possibility that sumoylation enables TDG to function, at least transiently, as reader of fC and caC. Notably, sumoylation could potentially facilitate TDG recruitment of other proteins, including transcription factors or epigenetic regulators, to these sites in DNA.
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Affiliation(s)
- Christopher T Coey
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Alexander C Drohat
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.,Molecular and Structural Biology Program, University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD 21201, USA
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16
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Steinacher R, Barekati Z, Botev P, Kuśnierczyk A, Slupphaug G, Schär P. SUMOylation coordinates BERosome assembly in active DNA demethylation during cell differentiation. EMBO J 2018; 38:embj.201899242. [PMID: 30523148 DOI: 10.15252/embj.201899242] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 11/05/2018] [Accepted: 11/09/2018] [Indexed: 11/09/2022] Open
Abstract
During active DNA demethylation, 5-methylcytosine (5mC) is oxidized by TET proteins to 5-formyl-/5-carboxylcytosine (5fC/5caC) for replacement by unmethylated C by TDG-initiated DNA base excision repair (BER). Base excision generates fragile abasic sites (AP-sites) in DNA and has to be coordinated with subsequent repair steps to limit accumulation of genome destabilizing secondary DNA lesions. Here, we show that 5fC/5caC is generated at a high rate in genomes of differentiating mouse embryonic stem cells and that SUMOylation and the BER protein XRCC1 play critical roles in orchestrating TDG-initiated BER of these lesions. SUMOylation of XRCC1 facilitates physical interaction with TDG and promotes the assembly of a TDG-BER core complex. Within this TDG-BERosome, SUMO is transferred from XRCC1 and coupled to the SUMO acceptor lysine in TDG, promoting its dissociation while assuring the engagement of the BER machinery to complete demethylation. Although well-studied, the biological importance of TDG SUMOylation has remained obscure. Here, we demonstrate that SUMOylation of TDG suppresses DNA strand-break accumulation and toxicity to PARP inhibition in differentiating mESCs and is essential for neural lineage commitment.
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Affiliation(s)
| | - Zeinab Barekati
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Petar Botev
- Institute of Molecular Biology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Anna Kuśnierczyk
- Department of Cancer Research and Molecular Medicine, Proteomics and Metabolomics Core Facility, PROMEC, Norwegian University of Science and Technology, Trondheim, Norway
| | - Geir Slupphaug
- Department of Cancer Research and Molecular Medicine, Proteomics and Metabolomics Core Facility, PROMEC, Norwegian University of Science and Technology, Trondheim, Norway
| | - Primo Schär
- Department of Biomedicine, University of Basel, Basel, Switzerland
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17
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Tarantino ME, Dow BJ, Drohat AC, Delaney S. Nucleosomes and the three glycosylases: High, medium, and low levels of excision by the uracil DNA glycosylase superfamily. DNA Repair (Amst) 2018; 72:56-63. [PMID: 30268365 DOI: 10.1016/j.dnarep.2018.09.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 09/16/2018] [Accepted: 09/17/2018] [Indexed: 01/19/2023]
Abstract
Human cells express the UDG superfamily of glycosylases, which excise uracil (U) from the genome. The three members of this structural superfamily are uracil DNA glycosylase (UNG/UDG), single-strand selective monofunctional uracil DNA glycosylase (SMUG1), and thymine DNA glycosylase (TDG). We previously reported that UDG is efficient at removing U from DNA packaged into nucleosome core particles (NCP) and is minimally affected by the histone proteins when acting on an outward-facing U in the dyad region. In an effort to determine whether this high activity is a general property of the UDG superfamily of glycosylases, we compare the activity of UDG, SMUG1, and TDG on a U:G wobble base pair using NCP assembled from Xenopus laevis histones and the Widom 601 positioning sequence. We found that while UDG is highly active, SMUG1 is severely inhibited on NCP and this inhibition is independent of sequence context. Here we also provide the first report of TDG activity on an NCP, and found that TDG has an intermediate level of activity in excision of U and is severely inhibited in its excision of T. These results are discussed in the context of cellular roles for each of these enzymes.
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Affiliation(s)
- Mary E Tarantino
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02912, United States
| | - Blaine J Dow
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States
| | - Alexander C Drohat
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, 21201, United States; University of Maryland Marlene and Stewart Greenebaum Cancer Center, Baltimore, MD, 21201, United States
| | - Sarah Delaney
- Department of Chemistry, Brown University, Providence, RI, 02912, United States.
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18
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Hassan HM, Kolendowski B, Isovic M, Bose K, Dranse HJ, Sampaio AV, Underhill TM, Torchia J. Regulation of Active DNA Demethylation through RAR-Mediated Recruitment of a TET/TDG Complex. Cell Rep 2018; 19:1685-1697. [PMID: 28538185 DOI: 10.1016/j.celrep.2017.05.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 03/28/2017] [Accepted: 05/01/2017] [Indexed: 02/07/2023] Open
Abstract
Retinoic acid (RA) plays important roles in development, growth, and homeostasis through regulation of the nuclear receptors for RA (RARs). Herein, we identify Hypermethylated in Cancer 1 (Hic1) as an RA-inducible gene. HIC1 encodes a tumor suppressor, which is often silenced by promoter hypermethylation in cancer. Treatment of cells with an RAR agonist causes a rapid recruitment of an RAR/RXR complex consisting of TDG, the lysine acetyltransferase CBP, and TET 1/2 to the Hic1 promoter. Complex binding coincides with a transient accumulation of 5fC/5caC and concomitant upregulation of Hic1 expression, both of which are TDG dependent. Furthermore, conditional deletion of Tdg in vivo is associated with Hic1 silencing and DNA hypermethylation of the Hic1 promoter. These findings suggest that the catalytic and scaffolding activities of TDG are essential for RA-dependent gene expression and provide important insights into the mechanisms underlying targeting of TET-TDG complexes.
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Affiliation(s)
- Haider M Hassan
- Department of Biochemistry, Western University, London, ON N6A 5C1, Canada; Department of Oncology, The London Regional Cancer Program and the Lawson Health Research Institute, London, ON N6A 4L6, Canada
| | - Bart Kolendowski
- Department of Biochemistry, Western University, London, ON N6A 5C1, Canada; Department of Oncology, The London Regional Cancer Program and the Lawson Health Research Institute, London, ON N6A 4L6, Canada
| | - Majdina Isovic
- Department of Oncology, The London Regional Cancer Program and the Lawson Health Research Institute, London, ON N6A 4L6, Canada
| | - Kerstin Bose
- Department of Cellular and Physiological Sciences and the Biomedical Research Centre, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Helen J Dranse
- Department of Cellular and Physiological Sciences and the Biomedical Research Centre, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Arthur V Sampaio
- Department of Cellular and Physiological Sciences and the Biomedical Research Centre, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - T Michael Underhill
- Department of Cellular and Physiological Sciences and the Biomedical Research Centre, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
| | - Joseph Torchia
- Department of Biochemistry, Western University, London, ON N6A 5C1, Canada; Department of Oncology, The London Regional Cancer Program and the Lawson Health Research Institute, London, ON N6A 4L6, Canada.
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19
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Kolendowski B, Hassan H, Krstic M, Isovic M, Thillainadesan G, Chambers AF, Tuck AB, Torchia J. Genome-wide analysis reveals a role for TDG in estrogen receptor-mediated enhancer RNA transcription and 3-dimensional reorganization. Epigenetics Chromatin 2018; 11:5. [PMID: 29378668 PMCID: PMC5787930 DOI: 10.1186/s13072-018-0176-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 01/15/2018] [Indexed: 01/25/2023] Open
Abstract
Background The estrogen receptor (ER) is a ligand-dependant transcription factor expressed in many breast cancers and is the target of many endocrine-based cancer therapies. Genome-wide studies have shown that the ER binds to gene-specific enhancer regions in response to β-estradiol (E2) which undergo transcription producing noncoding enhancer RNA (eRNA). While eRNAs are important for transcriptional activation of neighboring genes, the mechanism remains poorly understood. Results Using ChIP-Seq we generate a global profile of thymine DNA glycosylase (TDG), an ER coactivator that plays an essential role in DNA demethylation, in response to E2 in the MCF7 breast cancer cell line. Remarkably, we found that in response to E2 TDG localized to enhancers which also recruit ERα, RNA Pol II and other coregulators and which are marked by histone modifications indicative of active enhancers. Importantly, depletion of TDG inhibits E2-mediated transcription of eRNAs and transcription of ER-target genes. Functionally, we find that TDG both sensitizes MCF7 cells to tamoxifen-mediated cytostasis and increases migration and invasion of MCF7 cells. Conclusions Taken together we find that TDG plays a central role in mediating transcription at a subset of enhancers and governs how MCF7 cells respond to both estrogenic and anti-estrogenic compounds and may be an effective therapeutic target. Electronic supplementary material The online version of this article (10.1186/s13072-018-0176-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bart Kolendowski
- Department of Biochemistry, Western University, London, ON, Canada.,Department of Oncology, Western University, London, ON, Canada.,The London Regional Cancer Program and the Lawson Health Research Institute, Western University, London, ON, Canada
| | - Haider Hassan
- Department of Biochemistry, Western University, London, ON, Canada.,Department of Oncology, Western University, London, ON, Canada.,The London Regional Cancer Program and the Lawson Health Research Institute, Western University, London, ON, Canada
| | - Milica Krstic
- Department of Pathology, Western University, London, ON, Canada.,The London Regional Cancer Program and the Lawson Health Research Institute, Western University, London, ON, Canada
| | - Majdina Isovic
- Department of Oncology, Western University, London, ON, Canada
| | - Gobi Thillainadesan
- Department of Biochemistry, Western University, London, ON, Canada.,Department of Oncology, Western University, London, ON, Canada
| | - Ann F Chambers
- The London Regional Cancer Program and the Lawson Health Research Institute, Western University, London, ON, Canada
| | - Alan B Tuck
- Department of Oncology, Western University, London, ON, Canada.,Department of Pathology, Western University, London, ON, Canada
| | - Joseph Torchia
- Department of Biochemistry, Western University, London, ON, Canada. .,Department of Oncology, Western University, London, ON, Canada. .,The London Regional Cancer Program and the Lawson Health Research Institute, Western University, London, ON, Canada. .,Cancer Research Laboratories, London Regional Cancer Program, London, ON, N6A 4L6, Canada.
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20
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Ho JJ, Cattoglio C, McSwiggen DT, Tjian R, Fong YW. Regulation of DNA demethylation by the XPC DNA repair complex in somatic and pluripotent stem cells. Genes Dev 2017; 31:830-844. [PMID: 28512237 PMCID: PMC5435894 DOI: 10.1101/gad.295741.116] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Accepted: 04/14/2017] [Indexed: 12/19/2022]
Abstract
In this study, Ho et al. research the mechanism by which TDG-dependent DNA demethylation occurs in a rapid and site-specific manner. Their findings demonstrate two distinct but complementary mechanisms by which XPC influences gene regulation by coordinating efficient TDG-mediated DNA demethylation along with active transcription during somatic cell reprogramming. Faithful resetting of the epigenetic memory of a somatic cell to a pluripotent state during cellular reprogramming requires DNA methylation to silence somatic gene expression and dynamic DNA demethylation to activate pluripotency gene transcription. The removal of methylated cytosines requires the base excision repair enzyme TDG, but the mechanism by which TDG-dependent DNA demethylation occurs in a rapid and site-specific manner remains unclear. Here we show that the XPC DNA repair complex is a potent accelerator of global and locus-specific DNA demethylation in somatic and pluripotent stem cells. XPC cooperates with TDG genome-wide to stimulate the turnover of essential intermediates by overcoming slow TDG–abasic product dissociation during active DNA demethylation. We further establish that DNA demethylation induced by XPC expression in somatic cells overcomes an early epigenetic barrier in cellular reprogramming and facilitates the generation of more robust induced pluripotent stem cells, characterized by enhanced pluripotency-associated gene expression and self-renewal capacity. Taken together with our previous studies establishing the XPC complex as a transcriptional coactivator, our findings underscore two distinct but complementary mechanisms by which XPC influences gene regulation by coordinating efficient TDG-mediated DNA demethylation along with active transcription during somatic cell reprogramming.
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Affiliation(s)
- Jaclyn J Ho
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, California Institute for Regenerative Medicine Center of Excellence, University of California at Berkeley, Berkeley, California 94720, USA.,Howard Hughes Medical Institute, Berkeley, California 94720, USA
| | - Claudia Cattoglio
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, California Institute for Regenerative Medicine Center of Excellence, University of California at Berkeley, Berkeley, California 94720, USA.,Howard Hughes Medical Institute, Berkeley, California 94720, USA
| | - David T McSwiggen
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, California Institute for Regenerative Medicine Center of Excellence, University of California at Berkeley, Berkeley, California 94720, USA
| | - Robert Tjian
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, California Institute for Regenerative Medicine Center of Excellence, University of California at Berkeley, Berkeley, California 94720, USA.,Howard Hughes Medical Institute, Berkeley, California 94720, USA
| | - Yick W Fong
- Brigham Regenerative Medicine Center, Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Cambridge, Massachusetts 02115, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts 02138, USA
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21
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Xu J, Cortellino S, Tricarico R, Chang WC, Scher G, Devarajan K, Slifker M, Moore R, Bassi MR, Caretti E, Clapper M, Cooper H, Bellacosa A. Thymine DNA Glycosylase (TDG) is involved in the pathogenesis of intestinal tumors with reduced APC expression. Oncotarget 2017; 8:89988-89997. [PMID: 29163805 PMCID: PMC5685726 DOI: 10.18632/oncotarget.21219] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 08/21/2017] [Indexed: 12/22/2022] Open
Abstract
Thymine DNA Glycosylase (TDG) is a base excision repair enzyme that acts as a thymine and uracil DNA N-glycosylase on G:T and G:U mismatches, thus protecting CpG sites in the genome from mutagenesis by deamination. In addition, TDG has an epigenomic function by removing the novel cytosine derivatives 5-formylcytosine and 5-carboxylcytosine (5caC) generated by Ten-Eleven Translocation (TET) enzymes during active DNA demethylation. We and others previously reported that TDG is essential for mammalian development. However, its involvement in tumor formation is unknown. To study the role of TDG in tumorigenesis, we analyzed the effects of its inactivation in a well-characterized model of tumor predisposition, the ApcMin mouse strain. Mice bearing a conditional Tdgflox allele were crossed with Fabpl::Cre transgenic mice, in the context of the ApcMin mutation, in order to inactivate Tdg in the small intestinal and colonic epithelium. We observed an approximately 2-fold increase in the number of small intestinal adenomas in the test Tdg-mutant ApcMin mice in comparison to control genotypes (p=0.0001). This increase occurred in female mice, and is similar to the known increase in intestinal adenoma formation due to oophorectomy. In the human colorectal cancer (CRC) TCGA database, the subset of patients with TDG and APC expression in the lowest quartile exhibits an excess of female cases. We conclude that TDG inactivation plays a role in intestinal tumorigenesis initiated by mutation/underexpression of APC. Our results also indicate that TDG may be involved in sex-specific protection from CRC.
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Affiliation(s)
- Jinfei Xu
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Salvatore Cortellino
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Rossella Tricarico
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Wen-Chi Chang
- Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Gabrielle Scher
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Karthik Devarajan
- Department of Biostatistics, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Michael Slifker
- Department of Biostatistics, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Robert Moore
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Maria Rosaria Bassi
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Elena Caretti
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Margie Clapper
- Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Harry Cooper
- Department of Pathology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Alfonso Bellacosa
- Cancer Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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22
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Alavian-Ghavanini A, Rüegg J. Understanding Epigenetic Effects of Endocrine Disrupting Chemicals: From Mechanisms to Novel Test Methods. Basic Clin Pharmacol Toxicol 2017; 122:38-45. [PMID: 28842957 DOI: 10.1111/bcpt.12878] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 08/21/2017] [Indexed: 01/20/2023]
Abstract
Endocrine-disrupting chemicals (EDCs) are man-made chemicals that interfere with hormonal signalling pathways. They are used in, for example, production of common household materials, in resin-based medical supplies and in pesticides. Thus, they are environmentally ubiquitous and human beings and wildlife are exposed to them on a daily basis. Early-life exposure to EDCs has been associated with later-life adversities such as obesity, diabetes and cancer. Mechanisms underlying such associations are unknown but are likely to be mediated by epigenetic changes induced by EDCs. Epigenetics is the study of changes in gene function that are heritable but do not entail a change in DNA sequence. EDCs have been shown to affect epigenetic marks such as DNA methylation and histone modifications. The scope of this article was to review today's knowledge about mechanisms involved in EDC-induced epigenetic changes and to discuss how this knowledge could be used for designing novel methods addressing epigenetic effects of EDCs.
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Affiliation(s)
- Ali Alavian-Ghavanini
- Unit of Toxicology Sciences, Swetox, Department of Clinical Neurosciences, Karolinska Institutet, Södertälje, Sweden
| | - Joëlle Rüegg
- Unit of Toxicology Sciences, Swetox, Department of Clinical Neurosciences, Karolinska Institutet, Södertälje, Sweden
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23
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Limpose KL, Corbett AH, Doetsch PW. BERing the burden of damage: Pathway crosstalk and posttranslational modification of base excision repair proteins regulate DNA damage management. DNA Repair (Amst) 2017. [PMID: 28629773 DOI: 10.1016/j.dnarep.2017.06.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
DNA base damage and non-coding apurinic/apyrimidinic (AP) sites are ubiquitous types of damage that must be efficiently repaired to prevent mutations. These damages can occur in both the nuclear and mitochondrial genomes. Base excision repair (BER) is the frontline pathway for identifying and excising damaged DNA bases in both of these cellular compartments. Recent advances demonstrate that BER does not operate as an isolated pathway but rather dynamically interacts with components of other DNA repair pathways to modulate and coordinate BER functions. We define the coordination and interaction between DNA repair pathways as pathway crosstalk. Numerous BER proteins are modified and regulated by post-translational modifications (PTMs), and PTMs could influence pathway crosstalk. Here, we present recent advances on BER/DNA repair pathway crosstalk describing specific examples and also highlight regulation of BER components through PTMs. We have organized and reported functional interactions and documented PTMs for BER proteins into a consolidated summary table. We further propose the concept of DNA repair hubs that coordinate DNA repair pathway crosstalk to identify central protein targets that could play a role in designing future drug targets.
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Affiliation(s)
- Kristin L Limpose
- Graduate Program in Cancer Biology, Emory University, Atlanta, GA, 30322, United States
| | - Anita H Corbett
- Department of Biology, Emory University, Atlanta, GA, 30322, United States; Winship Cancer Institute, Emory University, Atlanta, GA 30322, United States.
| | - Paul W Doetsch
- Graduate Program in Cancer Biology, Emory University, Atlanta, GA, 30322, United States; Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA, 30322, United States; Winship Cancer Institute, Emory University, Atlanta, GA 30322, United States; Department of Biochemistry, Emory University, Atlanta, GA, 30322, United States.
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24
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Tudek B, Zdżalik-Bielecka D, Tudek A, Kosicki K, Fabisiewicz A, Speina E. Lipid peroxidation in face of DNA damage, DNA repair and other cellular processes. Free Radic Biol Med 2017; 107:77-89. [PMID: 27908783 DOI: 10.1016/j.freeradbiomed.2016.11.043] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 11/20/2016] [Accepted: 11/27/2016] [Indexed: 01/09/2023]
Abstract
Exocyclic adducts to DNA bases are formed as a consequence of exposure to certain environmental carcinogens as well as inflammation and lipid peroxidation (LPO). Complex family of LPO products gives rise to a variety of DNA adducts, which can be grouped in two classes: (i) small etheno-type adducts of strong mutagenic potential, and (ii) bulky, propano-type adducts, which block replication and transcription, and are lethal lesions. Etheno-DNA adducts are removed from the DNA by base excision repair (BER), AlkB and nucleotide incision repair enzymes (NIR), while substituted propano-type lesions by nucleotide excision repair (NER) and homologous recombination (HR). Changes of the level and activity of several enzymes removing exocyclic adducts from the DNA was reported during carcinogenesis. Also several beyond repair functions of these enzymes, which participate in regulation of cell proliferation and growth, as well as RNA processing was recently described. In addition, adducts of LPO products to proteins was reported during aging and age-related diseases. The paper summarizes pathways for exocyclic adducts removal and describes how proteins involved in repair of these adducts can modify pathological states of the organism.
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Affiliation(s)
- Barbara Tudek
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
| | - Daria Zdżalik-Bielecka
- Laboratory of Cell Biology, International Institute of Molecular and Cell Biology, Ksiecia Trojdena 4, 02-109 Warsaw, Poland
| | - Agnieszka Tudek
- Department of Molecular Biology and Genetics, Aarhus University, C. F. Mollers Alle 3, 8000 Aarhus, Denmark
| | - Konrad Kosicki
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Anna Fabisiewicz
- Department of Molecular and Translational Oncology, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Roentgena 5, Warsaw 02-781, Poland
| | - Elżbieta Speina
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
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25
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Nakamura T, Murakami K, Tada H, Uehara Y, Nogami J, Maehara K, Ohkawa Y, Saitoh H, Nishitani H, Ono T, Nishi R, Yokoi M, Sakai W, Sugasawa K. Thymine DNA glycosylase modulates DNA damage response and gene expression by base excision repair-dependent and independent mechanisms. Genes Cells 2017; 22:392-405. [PMID: 28318075 DOI: 10.1111/gtc.12481] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 02/01/2017] [Indexed: 02/04/2023]
Abstract
Thymine DNA glycosylase (TDG) is a base excision repair (BER) enzyme, which is implicated in correction of deamination-induced DNA mismatches, the DNA demethylation process and regulation of gene expression. Because of these pivotal roles associated, it is crucial to elucidate how the TDG functions are appropriately regulated in vivo. Here, we present evidence that the TDG protein undergoes degradation upon various types of DNA damage, including ultraviolet light (UV). The UV-induced degradation of TDG was dependent on proficiency in nucleotide excision repair and on CRL4CDT2 -mediated ubiquitination that requires a physical interaction between TDG and DNA polymerase clamp PCNA. Using the Tdg-deficient mouse embryonic fibroblasts, we found that ectopic expression of TDG compromised cellular survival after UV irradiation and repair of UV-induced DNA lesions. These negative effects on cellular UV responses were alleviated by introducing mutations in TDG that impaired its BER function. The expression of TDG induced a large-scale alteration in the gene expression profile independently of its DNA glycosylase activity, whereas a subset of genes was affected by the catalytic activity of TDG. Our results indicate the presence of BER-dependent and BER-independent functions of TDG, which are involved in regulation of cellular DNA damage responses and gene expression patterns.
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Affiliation(s)
- Tomohumi Nakamura
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan.,Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| | - Kouichi Murakami
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan.,Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| | - Haruto Tada
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan.,Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| | - Yoshihiko Uehara
- Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Jumpei Nogami
- Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-0054, Japan
| | - Kazumitsu Maehara
- Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-0054, Japan
| | - Yasuyuki Ohkawa
- Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-0054, Japan
| | - Hisato Saitoh
- Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, 860-8555, Japan
| | - Hideo Nishitani
- Graduate School of Life Science, University of Hyogo, Kamigori, 678-1297, Japan
| | - Tetsuya Ono
- Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Ryotaro Nishi
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan
| | - Masayuki Yokoi
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan.,Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| | - Wataru Sakai
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan.,Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| | - Kaoru Sugasawa
- Biosignal Research Center, Kobe University, Kobe, 657-8501, Japan.,Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
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26
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Genes, Gender, Environment, and Novel Functions of Estrogen Receptor Beta in the Susceptibility to Neurodevelopmental Disorders. Brain Sci 2017; 7:brainsci7030024. [PMID: 28241485 PMCID: PMC5366823 DOI: 10.3390/brainsci7030024] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 02/14/2017] [Accepted: 02/17/2017] [Indexed: 12/30/2022] Open
Abstract
Many neurological disorders affect men and women differently regarding prevalence, progression, and severity. It is clear that many of these disorders may originate from defective signaling during fetal or perinatal brain development, which may affect males and females differently. Such sex-specific differences may originate from chromosomal or sex-hormone specific effects. This short review will focus on the estrogen receptor beta (ERβ) signaling during perinatal brain development and put it in the context of sex-specific differences in neurodevelopmental disorders. We will discuss ERβ’s recent discovery in directing DNA de-methylation to specific sites, of which one such site may bear consequences for the susceptibility to the neurological reading disorder dyslexia. We will also discuss how dysregulations in sex-hormone signaling, like those evoked by endocrine disruptive chemicals, may affect this and other neurodevelopmental disorders in a sex-specific manner through ERβ.
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27
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McLaughlin D, Coey CT, Yang WC, Drohat AC, Matunis MJ. Characterizing Requirements for Small Ubiquitin-like Modifier (SUMO) Modification and Binding on Base Excision Repair Activity of Thymine-DNA Glycosylase in Vivo. J Biol Chem 2016; 291:9014-24. [PMID: 26917720 DOI: 10.1074/jbc.m115.706325] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Indexed: 12/12/2022] Open
Abstract
Thymine-DNA glycosylase (TDG) plays critical roles in DNA base excision repair and DNA demethylation. It has been proposed, based on structural studies and in vitro biochemistry, that sumoylation is required for efficient TDG enzymatic turnover following base excision. However, whether sumoylation is required for TDG activity in vivo has not previously been tested. We have developed an in vivo assay for TDG activity that takes advantage of its recently discovered role in DNA demethylation and selective recognition and repair of 5-carboxylcytosine. Using this assay, we investigated the role of sumoylation in regulating TDG activity through the use of TDG mutants defective for sumoylation and Small Ubiquitin-like Modifier (SUMO) binding and by altering TDG sumoylation through SUMO and SUMO protease overexpression experiments. Our findings indicate that sumoylation and SUMO binding are not essential for TDG-mediated excision and repair of 5-carboxylcytosine bases. Moreover, in vitro assays revealed that apurinic/apyrimidinic nuclease 1 provides nearly maximum stimulation of TDG processing of G·caC substrates. Thus, under our assay conditions, apurinic/apyrimidinic nuclease 1-mediated stimulation or other mechanisms sufficiently alleviate TDG product inhibition and promote its enzymatic turnover in vivo.
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Affiliation(s)
- Dylan McLaughlin
- From the Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205 and
| | - Christopher T Coey
- the Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Wei-Chih Yang
- From the Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205 and
| | - Alexander C Drohat
- the Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Michael J Matunis
- From the Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205 and
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28
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Liu Y, Duong W, Krawczyk C, Bretschneider N, Borbély G, Varshney M, Zinser C, Schär P, Rüegg J. Oestrogen receptor β regulates epigenetic patterns at specific genomic loci through interaction with thymine DNA glycosylase. Epigenetics Chromatin 2016; 9:7. [PMID: 26889208 PMCID: PMC4756533 DOI: 10.1186/s13072-016-0055-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 01/27/2016] [Indexed: 02/08/2023] Open
Abstract
Background DNA methylation is one way to encode epigenetic information and plays a crucial role in regulating gene expression during embryonic development. DNA methylation marks are established by the DNA methyltransferases and, recently, a mechanism for active DNA demethylation has emerged involving the ten-eleven translocator proteins and thymine DNA glycosylase (TDG). However, so far it is not clear how these enzymes are recruited to, and regulate DNA methylation at, specific genomic loci. A number of studies imply that sequence-specific transcription factors are involved in targeting DNA methylation and demethylation processes. Oestrogen receptor beta (ERβ) is a ligand-inducible transcription factor regulating gene expression in response to the female sex hormone oestrogen. Previously, we found that ERβ deficiency results in changes in DNA methylation patterns at two gene promoters, implicating an involvement of ERβ in DNA methylation. In this study, we set out to explore this involvement on a genome-wide level, and to investigate the underlying mechanisms of this function. Results Using reduced representation bisulfite sequencing, we compared genome-wide DNA methylation in mouse embryonic fibroblasts derived from wildtype and ERβ knock-out mice, and identified around 8000 differentially methylated positions (DMPs). Validation and further characterisation of selected DMPs showed that differences in methylation correlated with changes in expression of the nearest gene. Additionally, re-introduction of ERβ into the knock-out cells could reverse hypermethylation and reactivate expression of some of the genes. We also show that ERβ is recruited to regions around hypermethylated DMPs. Finally, we demonstrate here that ERβ interacts with TDG and that TDG binds ERβ-dependently to hypermethylated DMPs. Conclusion We provide evidence that ERβ plays a role in regulating DNA methylation at specific genomic loci, likely as the result of its interaction with TDG at these regions. Our findings imply a novel function of ERβ, beyond direct transcriptional control, in regulating DNA methylation at target genes. Further, they shed light on the question how DNA methylation is regulated at specific genomic loci by supporting a concept in which sequence-specific transcription factors can target factors that regulate DNA methylation patterns. Electronic supplementary material The online version of this article (doi:10.1186/s13072-016-0055-7) contains supplementary material, which is available to authorised users.
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Affiliation(s)
- Yun Liu
- Department of Biochemistry and Molecular Biology, Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Fudan University Shanghai Medical College, Shanghai, People's Republic of China
| | - William Duong
- Department of Biomedicine, University of Basel, Mattenstrasse 28, 4058 Basel, Switzerland.,Novartis Institutes for BioMedical Research, Novartis Pharma AG, Werk Klybeck, 4002 Basel, Switzerland
| | - Claudia Krawczyk
- Department of Biomedicine, University of Basel, Mattenstrasse 28, 4058 Basel, Switzerland
| | | | - Gábor Borbély
- Swedish Toxicology Science Research Center (Swetox), Forskargatan 20, 151 36 Södertälje, Sweden
| | - Mukesh Varshney
- Department of Biosciences and Nutrition, Karolinska Institutet at Novum, 141 83 Stockholm, Sweden
| | - Christian Zinser
- Swedish Toxicology Science Research Center (Swetox), Forskargatan 20, 151 36 Södertälje, Sweden
| | - Primo Schär
- Department of Biomedicine, University of Basel, Mattenstrasse 28, 4058 Basel, Switzerland
| | - Joëlle Rüegg
- Department of Biomedicine, University of Basel, Mattenstrasse 28, 4058 Basel, Switzerland.,Swedish Toxicology Science Research Center (Swetox), Forskargatan 20, 151 36 Södertälje, Sweden.,Department of Clinical Neurosciences, Karolinska Institutet, CMM L8:00, 171 76 Stockholm, Sweden
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29
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Xu X, Watt DS, Liu C. Multifaceted roles for thymine DNA glycosylase in embryonic development and human carcinogenesis. Acta Biochim Biophys Sin (Shanghai) 2016; 48:82-9. [PMID: 26370152 DOI: 10.1093/abbs/gmv083] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 07/12/2015] [Indexed: 01/03/2023] Open
Abstract
Thymine DNA glycosylase (TDG) is a multifunctional protein that plays important roles in DNA repair, DNA demethylation, and transcriptional regulation. These diverse functions make TDG a unique enzyme in embryonic development and carcinogenesis. This review discusses the molecular function of TDG in human cancers and the previously unrecognized value of TDG as a potential target for drug therapy.
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Affiliation(s)
- Xuehe Xu
- Department of Molecular and Cellular Biochemistry, Markey Cancer Center, University of Kentucky, Lexington, KY 40536-0509, USA
| | - David S Watt
- Department of Molecular and Cellular Biochemistry, Markey Cancer Center, University of Kentucky, Lexington, KY 40536-0509, USA
| | - Chunming Liu
- Department of Molecular and Cellular Biochemistry, Markey Cancer Center, University of Kentucky, Lexington, KY 40536-0509, USA
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30
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Bauer NC, Corbett AH, Doetsch PW. The current state of eukaryotic DNA base damage and repair. Nucleic Acids Res 2015; 43:10083-101. [PMID: 26519467 PMCID: PMC4666366 DOI: 10.1093/nar/gkv1136] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/16/2015] [Indexed: 12/15/2022] Open
Abstract
DNA damage is a natural hazard of life. The most common DNA lesions are base, sugar, and single-strand break damage resulting from oxidation, alkylation, deamination, and spontaneous hydrolysis. If left unrepaired, such lesions can become fixed in the genome as permanent mutations. Thus, evolution has led to the creation of several highly conserved, partially redundant pathways to repair or mitigate the effects of DNA base damage. The biochemical mechanisms of these pathways have been well characterized and the impact of this work was recently highlighted by the selection of Tomas Lindahl, Aziz Sancar and Paul Modrich as the recipients of the 2015 Nobel Prize in Chemistry for their seminal work in defining DNA repair pathways. However, how these repair pathways are regulated and interconnected is still being elucidated. This review focuses on the classical base excision repair and strand incision pathways in eukaryotes, considering both Saccharomyces cerevisiae and humans, and extends to some important questions and challenges facing the field of DNA base damage repair.
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Affiliation(s)
- Nicholas C Bauer
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA Graduate Program in Biochemistry, Cell, and Developmental Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Anita H Corbett
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Paul W Doetsch
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, USA Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, GA 30322, USA
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31
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Bellacosa A, Drohat AC. Role of base excision repair in maintaining the genetic and epigenetic integrity of CpG sites. DNA Repair (Amst) 2015; 32:33-42. [PMID: 26021671 DOI: 10.1016/j.dnarep.2015.04.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cytosine methylation at CpG dinucleotides is a central component of epigenetic regulation in vertebrates, and the base excision repair (BER) pathway is important for maintaining both the genetic stability and the methylation status of CpG sites. This perspective focuses on two enzymes that are of particular importance for the genetic and epigenetic integrity of CpG sites, methyl binding domain 4 (MBD4) and thymine DNA glycosylase (TDG). We discuss their capacity for countering C to T mutations at CpG sites, by initiating base excision repair of G · T mismatches generated by deamination of 5-methylcytosine (5mC). We also consider their role in active DNA demethylation, including pathways that are initiated by oxidation and/or deamination of 5mC.
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Affiliation(s)
- Alfonso Bellacosa
- Cancer Epigenetics Program, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, United States.
| | - Alexander C Drohat
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene St., Baltimore, MD 21201, United States.
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32
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Hong JS, Kim NH, Choi CY, Lee JS, Na D, Chun T, Lee YS. Changes in cellular microRNA expression induced by porcine circovirus type 2-encoded proteins. Vet Res 2015; 46:39. [PMID: 25885539 PMCID: PMC4391141 DOI: 10.1186/s13567-015-0172-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 03/17/2015] [Indexed: 12/21/2022] Open
Abstract
Porcine circovirus type 2 (PCV2) is the primary causative agent of postweaning multisystemic wasting syndrome, which leads to serious economic losses in the pig industry worldwide. While the molecular basis of PCV2 replication and pathogenicity remains elusive, it is increasingly apparent that the microRNA (miRNA) pathway plays a key role in controlling virus-host interactions, in addition to a wide range of cellular processes. Here, we employed Solexa deep sequencing technology to determine which cellular miRNAs were differentially regulated after expression of each of three PCV2-encoded open reading frames (ORFs) in porcine kidney epithelial (PK15) cells. We identified 51 ORF1-regulated miRNAs, 74 ORF2-regulated miRNAs, and 32 ORF3-regulated miRNAs that differed in abundance compared to the control. Gene ontology analysis of the putative targets of these miRNAs identified transcriptional regulation as the most significantly enriched biological process, while KEGG pathway analysis revealed significant enrichment for several pathways including MAPK signaling, which is activated during PCV2 infection. Among the potential target genes of ORF-regulated miRNAs, two genes encoding proteins that are known to interact with PCV2-encoded proteins, zinc finger protein 265 (ZNF265) and regulator of G protein signaling 16 (RGS16), were selected for further analysis. We provide evidence that ZNF265 and RGS16 are direct targets of miR-139-5p and let-7e, respectively, which are both down-regulated by ORF2. Our data will initiate further studies to elucidate the roles of ORF-regulated cellular miRNAs in PCV2-host interactions.
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Affiliation(s)
- Jae-Sang Hong
- College of Life Sciences and Biotechnology, Korea University, Seoul, 136-713, Korea.
| | - Nam-Hoon Kim
- College of Life Sciences and Biotechnology, Korea University, Seoul, 136-713, Korea.
| | - Chang-Yong Choi
- College of Life Sciences and Biotechnology, Korea University, Seoul, 136-713, Korea.
| | - Jun-Seong Lee
- College of Life Sciences and Biotechnology, Korea University, Seoul, 136-713, Korea. .,Present address: Institut de Recherches Cliniques de Montréal, Montréal, Québec, H2W1R7, Canada.
| | - Dokyun Na
- School of Integrative Engineering, Chung-Ang University, Seoul, 156-756, Korea.
| | - Taehoon Chun
- College of Life Sciences and Biotechnology, Korea University, Seoul, 136-713, Korea.
| | - Young Sik Lee
- College of Life Sciences and Biotechnology, Korea University, Seoul, 136-713, Korea.
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33
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Wang KY, Chen CC, Shen CKJ. Active DNA demethylation of the vertebrate genomes by DNA methyltransferases: deaminase, dehydroxymethylase or demethylase? Epigenomics 2015; 6:353-63. [PMID: 25111488 DOI: 10.2217/epi.14.21] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Vertebrate DNA methyltransferases (DNMTs) have been thought to primarily function to covalently add a methyl group to the 5-position of cytosine. However, recent discovery of the DNA demethylation and dehydroxymethylation activities of DNMTs in vitro suggest new routes to complete the dynamic cycle of DNA methylation-demethylation of the vertebrate genomes. The in vitro reaction conditions suggest that vertebrate DNMTs can switch from DNA methylases to DNA dehydroxymethylases under oxidative stress and to DNA demethylases in the presence of calcium ion under nonreducing conditions. These environmental parameters provide clues regarding the choices in vivo of DNMT activities utilized in different physiological systems. In particular, the nature of these parameters suggest that the DNA demethylation and dehydroxymethylation activities of the vertebrate DNMTs play essential roles in multiple biological processes including early embryo development, regulation of neuronal plasticity, tumorigenesis and hormone-regulated transcription.
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Affiliation(s)
- Keh-Yang Wang
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 115, Taiwan
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34
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Ehara T, Kamei Y, Yuan X, Takahashi M, Kanai S, Tamura E, Tsujimoto K, Tamiya T, Nakagawa Y, Shimano H, Takai-Igarashi T, Hatada I, Suganami T, Hashimoto K, Ogawa Y. Ligand-activated PPARα-dependent DNA demethylation regulates the fatty acid β-oxidation genes in the postnatal liver. Diabetes 2015; 64:775-84. [PMID: 25311726 DOI: 10.2337/db14-0158] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The metabolic function of the liver changes sequentially during early life in mammals to adapt to the marked changes in nutritional environment. Accordingly, hepatic fatty acid β-oxidation is activated after birth to produce energy from breast milk lipids. However, how it is induced during the neonatal period is poorly understood. Here we show DNA demethylation and increased mRNA expression of the fatty acid β-oxidation genes in the postnatal mouse liver. The DNA demethylation does not occur in the fetal mouse liver under the physiologic condition, suggesting that it is specific to the neonatal period. Analysis of mice deficient in the nuclear receptor peroxisome proliferator-activated receptor α (PPARα) and maternal administration of a PPARα ligand during the gestation and lactation periods reveal that the DNA demethylation is PPARα dependent. We also find that DNA methylation of the fatty acid β-oxidation genes are reduced in the adult human liver relative to the fetal liver. This study represents the first demonstration that the ligand-activated PPARα-dependent DNA demethylation regulates the hepatic fatty acid β-oxidation genes during the neonatal period, thereby highlighting the role of a lipid-sensing nuclear receptor in the gene- and life-stage-specific DNA demethylation of a particular metabolic pathway.
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Affiliation(s)
- Tatsuya Ehara
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan Nutrition Research Department, Nutritional Science Institute, Morinaga Milk Industry Co. Ltd., Zama, Kanagawa, Japan
| | - Yasutomi Kamei
- Department of Organ Network and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Xunmei Yuan
- Department of Organ Network and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Mayumi Takahashi
- Department of Organ Network and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Sayaka Kanai
- Department of Organ Network and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Erina Tamura
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Kazutaka Tsujimoto
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Takashi Tamiya
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Yoshimi Nakagawa
- Department of Internal Medicine (Metabolism and Endocrinology), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Hitoshi Shimano
- Department of Internal Medicine (Metabolism and Endocrinology), Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takako Takai-Igarashi
- Department of Health Record Informatics, Tohoku Medical Megabank Organization, Aoba-ku, Sendai, Miyagi, Japan
| | - Izuho Hatada
- Genome Science, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
| | - Takayoshi Suganami
- Department of Organ Network and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan Japan Science and Technology Agency, PRESTO, Goban-cho Chiyoda-ku, Tokyo, Japan
| | - Koshi Hashimoto
- Department of Preemptive Medicine and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Yoshihiro Ogawa
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
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35
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Romagnolo DF, Zempleni J, Selmin OI. Nuclear receptors and epigenetic regulation: opportunities for nutritional targeting and disease prevention. Adv Nutr 2014; 5:373-85. [PMID: 25022987 PMCID: PMC4085186 DOI: 10.3945/an.114.005868] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Posttranslational modifications of histones, alterations in the recruitment and functions of non-histone proteins, DNA methylation, and changes in expression of noncoding RNAs contribute to current models of epigenetic regulation. Nuclear receptors (NRs) are a group of transcription factors that, through ligand-binding, act as sensors to changes in nutritional, environmental, developmental, pathophysiologic, and endocrine conditions and drive adaptive responses via gene regulation. One mechanism through which NRs direct gene expression is the assembly of transcription complexes with cofactors and coregulators that possess chromatin-modifying properties. Chromatin modifications can be transient or become part of the cellular "memory" and contribute to genomic imprinting. Because many food components bind to NRs, they can ultimately influence transcription of genes associated with biologic processes, such as inflammation, proliferation, apoptosis, and hormonal response, and alter the susceptibility to chronic diseases (e.g., cancer, diabetes, obesity). The objective of this review is to highlight how NRs influence epigenetic regulation and the relevance of dietary compound-NR interactions in human nutrition and for disease prevention and treatment. Identifying gene targets of unliganded and bound NRs may assist in the development of epigenetic maps for food components and dietary patterns. Progress in these areas may lead to the formulation of disease-prevention models based on epigenetic control by individual or associations of food ligands of NRs.
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Affiliation(s)
- Donato F Romagnolo
- Department of Nutritional Sciences and University of Arizona Cancer Center, University of Arizona, Tucson, AZ; and
| | - Janos Zempleni
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE
| | - Ornella I Selmin
- Department of Nutritional Sciences and University of Arizona Cancer Center, University of Arizona, Tucson, AZ; and
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36
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Shibata E, Dar A, Dutta A. CRL4Cdt2 E3 ubiquitin ligase and proliferating cell nuclear antigen (PCNA) cooperate to degrade thymine DNA glycosylase in S phase. J Biol Chem 2014; 289:23056-23064. [PMID: 24962565 DOI: 10.1074/jbc.m114.574210] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Thymine DNA glycosylase (TDG) is an essential enzyme playing multiple roles in base excision repair, transcription regulation, and DNA demethylation. TDG mediates the cytotoxicity of the anti-cancer chemotherapeutic drug 5-fluorouracil (5-FU) by prolonging S phase, generating DNA strand breaks, and inducing DNA damage signaling. During S phase of the cell cycle, TDG is degraded via the proteasomal pathway. Here we show that CRL4(Cdt2) E3 ubiquitin ligase promotes ubiquitination and proteasomal degradation of TDG in S phase in a reaction that is dependent on the interaction of TDG with proliferating cell nuclear antigen (PCNA). siRNA-mediated depletion of PCNA or components of CRL4(Cdt2), specifically cullin4A/B or substrate adaptor Cdt2, stabilizes TDG in human cells. Mutations in the PCNA-interacting peptide (PIP) motif of TDG that disrupt the interaction of TDG with PCNA or change critical basic residues essential for the action of the PIP degron prevent the ubiquitination and degradation of TDG. Thus physical interaction of TDG with PCNA through the PIP degron is required for targeting TDG to the CRL4(Cdt2) E3 ubiquitin ligase complex. Compared with forced expression of wild type TDG, CRL4(Cdt2)- resistant TDG (ΔPIP) slows cell proliferation and slightly increases the toxicity of 5-FU. Thus, CRL4(Cdt2)-dependent degradation of TDG occurs in S phase because of the requirement for TDG to interact with chromatin-loaded PCNA, and this degradation is important for preventing toxicity from excess TDG.
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Affiliation(s)
- Etsuko Shibata
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908
| | - Ashraf Dar
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908
| | - Anindya Dutta
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia 22908.
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Abstract
Crystal structures represent the static picture in the life of a molecule giving a sneak preview what it might be in reality. Hence, it is very hard to extrapolate from these photos toward dynamic processes such as transcriptional regulation. Mechanistically VDR may be considered as molecular machine able to perform ligand-, DNA- and protein recognition, and interaction in a multi-task manner. Taking this into account the functional net effect will be the combination of all these processes. The long awaited answer to explain the differences in physiological effects for various ligands was one of the biggest disappointment that crystal structures provided since no substantial distinction could be made for the conformation of the active VDR-ligand complexes. This may have come from the limitation on the complexity of the available ligand-VDR structures. The recent studies with full length VDR-RXRα showed somewhat more comprehensive perspective for the 3D organization and possible function of the VDR-RXRα-cofactor complex. In addition to in vitro approaches, also computational tools had been introduced with the aim to get understanding on the mechanic and dynamic properties of the VDR complexes with some success. Using these methods and based on measurable descriptors such as pocket size and positions of side chains it is possible to note subtle differences between the structures. The meaning of these differences has not been fully understood yet but the possibility of a “butterfly effect” may have more extreme consequences in terms of VDR signaling. In this review, the three functional aspects (ligand-, DNA- and protein recognition, and binding) will be discussed with respect to available data as well as possible implication and questions that may be important to address in the future.
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Affiliation(s)
- Ferdinand Molnár
- Faculty of Health Sciences, School of Pharmacy, Institute of Biopharmacy, University of Eastern Finland Kuopio, Finland
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38
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Caldon CE. Estrogen signaling and the DNA damage response in hormone dependent breast cancers. Front Oncol 2014; 4:106. [PMID: 24860786 PMCID: PMC4030134 DOI: 10.3389/fonc.2014.00106] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 04/28/2014] [Indexed: 12/21/2022] Open
Abstract
Estrogen is necessary for the normal growth and development of breast tissue, but high levels of estrogen are a major risk factor for breast cancer. One mechanism by which estrogen could contribute to breast cancer is via the induction of DNA damage. This perspective discusses the mechanisms by which estrogen alters the DNA damage response (DDR) and DNA repair through the regulation of key effector proteins including ATM, ATR, CHK1, BRCA1, and p53 and the feedback on estrogen receptor signaling from these proteins. We put forward the hypothesis that estrogen receptor signaling converges to suppress effective DNA repair and apoptosis in favor of proliferation. This is important in hormone-dependent breast cancer as it will affect processing of estrogen-induced DNA damage, as well as other genotoxic insults. DDR and DNA repair proteins are frequently mutated or altered in estrogen responsive breast cancer, which will further change the processing of DNA damage. Finally, the action of estrogen signaling on DNA damage is also relevant to the therapeutic setting as the suppression of a DDR by estrogen has the potential to alter the response of cancers to anti-hormone treatment or chemotherapy that induces DNA damage.
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Affiliation(s)
- C Elizabeth Caldon
- Genome and Replication Stability Group, The Kinghorn Cancer Centre, Garvan Institute of Medical Research , Sydney, NSW , Australia ; St Vincent's Clinical School, Faculty of Medicine, UNSW Australia , Sydney, NSW , Australia
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39
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Coey CT, Fitzgerald ME, Maiti A, Reiter KH, Guzzo CM, Matunis MJ, Drohat AC. E2-mediated small ubiquitin-like modifier (SUMO) modification of thymine DNA glycosylase is efficient but not selective for the enzyme-product complex. J Biol Chem 2014; 289:15810-9. [PMID: 24753249 DOI: 10.1074/jbc.m114.572081] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thymine DNA glycosylase (TDG) initiates the repair of G·T mismatches that arise by deamination of 5-methylcytosine (mC), and it excises 5-formylcytosine and 5-carboxylcytosine, oxidized forms of mC. TDG functions in active DNA demethylation and is essential for embryonic development. TDG forms a tight enzyme-product complex with abasic DNA, which severely impedes enzymatic turnover. Modification of TDG by small ubiquitin-like modifier (SUMO) proteins weakens its binding to abasic DNA. It was proposed that sumoylation of product-bound TDG regulates product release, with SUMO conjugation and deconjugation needed for each catalytic cycle, but this model remains unsubstantiated. We examined the efficiency and specificity of TDG sumoylation using in vitro assays with purified E1 and E2 enzymes, finding that TDG is modified efficiently by SUMO-1 and SUMO-2. Remarkably, we observed similar modification rates for free TDG and TDG bound to abasic or undamaged DNA. To examine the conjugation step directly, we determined modification rates (kobs) using preformed E2∼SUMO-1 thioester. The hyperbolic dependence of kobs on TDG concentration gives kmax = 1.6 min(-1) and K1/2 = 0.55 μM, suggesting that E2∼SUMO-1 has higher affinity for TDG than for the SUMO targets RanGAP1 and p53 (peptide). Whereas sumoylation substantially weakens TDG binding to DNA, TDG∼SUMO-1 still binds relatively tightly to AP-DNA (Kd ∼50 nM). Although E2∼SUMO-1 exhibits no specificity for product-bound TDG, the relatively high conjugation efficiency raises the possibility that E2-mediated sumoylation could stimulate product release in vivo. This and other implications for the biological role and mechanism of TDG sumoylation are discussed.
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Affiliation(s)
- Christopher T Coey
- From the Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201 and
| | - Megan E Fitzgerald
- From the Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201 and
| | - Atanu Maiti
- From the Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201 and
| | - Katherine H Reiter
- the Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland 21205
| | - Catherine M Guzzo
- the Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland 21205
| | - Michael J Matunis
- the Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland 21205
| | - Alexander C Drohat
- From the Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201 and
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40
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Jia Y, Nie F, Du A, Chen Z, Qin Y, Huang T, Song X, Li L. Thymine DNA glycosylase promotes transactivation of β-catenin/TCFs by cooperating with CBP. J Mol Cell Biol 2014; 6:231-9. [PMID: 24748645 DOI: 10.1093/jmcb/mju014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Thymine DNA glycosylase (TDG), an enzyme that initiates the repair of G/T and G/U mismatches, has been lately found crucial in embryonic development to maintain epigenetic stability and facilitate the active DNA demethylation. Here we report a novel role of TDG in Wnt signaling as a transcriptional coactivator of β-catenin/TCFs complex. Our data show that TDG binds to the transcriptional factor family LEF1/TCFs and potentiates β-catenin/TCFs transactivation, while TDG depletion suppresses Wnt3a-stimulated reporter activity or target gene transcription. Next, we show that CBP, a known coactivator, is also required for TDG function through forming a cooperative complex on target promoters. Moreover, there is an elevation of TDG levels in human colon cancer tissue, and knockdown of TDG inhibits proliferation of the colon cells. Overall, our results reveal that TDG, as a new coactivator, promotes β-catenin/TCFs transactivation and functionally cooperates with CBP in canonical Wnt signaling.
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Affiliation(s)
- Yingying Jia
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Fen Nie
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Aiying Du
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zhangcheng Chen
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yuanbo Qin
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Tao Huang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xiaomin Song
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Lin Li
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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41
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Xu X, Yu T, Shi J, Chen X, Zhang W, Lin T, Liu Z, Wang Y, Zeng Z, Wang C, Li M, Liu C. Thymine DNA glycosylase is a positive regulator of Wnt signaling in colorectal cancer. J Biol Chem 2014; 289:8881-90. [PMID: 24532795 DOI: 10.1074/jbc.m113.538835] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Wnt signaling plays an important role in colorectal cancer (CRC). Although the mechanisms of β-catenin degradation have been well studied, the mechanism by which β-catenin activates transcription is still not fully understood. While screening a panel of DNA demethylases, we found that thymine DNA glycosylase (TDG) up-regulated Wnt signaling. TDG interacts with the transcription factor TCF4 and coactivator CREB-binding protein/p300 in the Wnt pathway. Knocking down TDG by shRNAs inhibited the proliferation of CRC cells in vitro and in vivo. In CRC patients, TDG levels were significantly higher in tumor tissues than in the adjacent normal tissues. These results suggest that TDG warrants consideration as a potential biomarker for CRC and as a target for CRC treatment.
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Affiliation(s)
- Xuehe Xu
- From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40506
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42
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Wyatt MD. Advances in understanding the coupling of DNA base modifying enzymes to processes involving base excision repair. Adv Cancer Res 2014; 119:63-106. [PMID: 23870509 DOI: 10.1016/b978-0-12-407190-2.00002-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This chapter describes some of the recent, exciting developments that have characterized and connected processes that modify DNA bases with DNA repair pathways. It begins with AID/APOBEC or TET family members that covalently modify bases within DNA. The modified bases, such as uracil or 5-formylcytosine, are then excised by DNA glycosylases including UNG or TDG to initiate base excision repair (BER). BER is known to preserve genome integrity by removing damaged bases. The newer studies underscore the necessity of BER following enzymes that deliberately damage DNA. This includes the role of BER in antibody diversification and more recently, its requirement for demethylation of 5-methylcytosine in mammalian cells. The recent advances have shed light on mechanisms of DNA demethylation, and have raised many more questions. The potential hazards of these processes have also been revealed. Dysregulation of the activity of base modifying enzymes, and resolution by unfaithful or corrupt means can be a driver of genome instability and tumorigenesis. The understanding of both DNA and histone methylation and demethylation is now revealing the true extent to which epigenetics influence normal development and cancer, an abnormal development.
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Affiliation(s)
- Michael D Wyatt
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina, USA.
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43
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Abstract
Transcription is apparently risky business. Its intrinsic mutagenic potential must be kept in check by networks of DNA repair factors that monitor the transcription process to repair DNA lesions that could otherwise compromise transcriptional fidelity and genome integrity. Intriguingly, recent studies point to an even more direct function of DNA repair complexes as coactivators of transcription and the unexpected role of "scheduled" DNA damage/repair at gene promoters. Paradoxically, spontaneous DNA double-strand breaks also induce ectopic transcription that is essential for repair. Thus, transcription, DNA damage, and repair may be more physically and functionally intertwined than previously appreciated.
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Affiliation(s)
- Yick W. Fong
- Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Claudia Cattoglio
- Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Robert Tjian
- Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
- Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, CA 94720, USA
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44
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Activation-induced cytidine deaminase (AID) is necessary for the epithelial-mesenchymal transition in mammary epithelial cells. Proc Natl Acad Sci U S A 2013; 110:E2977-86. [PMID: 23882083 DOI: 10.1073/pnas.1301021110] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Activation-induced cytidine deaminase (AID), which functions in antibody diversification, is also expressed in a variety of germ and somatic cells. Evidence that AID promotes DNA demethylation in epigenetic reprogramming phenomena, and that it is induced by inflammatory signals, led us to investigate its role in the epithelial-mesenchymal transition (EMT), a critical process in normal morphogenesis and tumor metastasis. We find that expression of AID is induced by inflammatory signals that induce the EMT in nontransformed mammary epithelial cells and in ZR75.1 breast cancer cells. shRNA-mediated knockdown of AID blocks induction of the EMT and prevents cells from acquiring invasive properties. Knockdown of AID suppresses expression of several key EMT transcriptional regulators and is associated with increased methylation of CpG islands proximal to the promoters of these genes; furthermore, the DNA demethylating agent 5 aza-2'deoxycytidine (5-Aza-dC) antagonizes the effects of AID knockdown on the expression of EMT factors. We conclude that AID is necessary for the EMT in this breast cancer cell model and in nontransformed mammary epithelial cells. Our results suggest that AID may act near the apex of a hierarchy of regulatory steps that drive the EMT, and are consistent with this effect being mediated by cytosine demethylation. This evidence links our findings to other reports of a role for AID in epigenetic reprogramming and control of gene expression.
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45
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Shim MK, Lee YJ. Estrogen receptor is activated by korean red ginseng in vitro but not in vivo. J Ginseng Res 2013; 36:169-75. [PMID: 23717117 PMCID: PMC3659583 DOI: 10.5142/jgr.2012.36.2.169] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 01/31/2012] [Accepted: 02/10/2012] [Indexed: 12/21/2022] Open
Abstract
Ginseng has been used as a traditional medicine for treatment of many diseases and for general health maintenance in people of all ages. Ginseng is also used to ameliorate menopausal systems. We investigated the estrogenic activity of Korean red ginseng (KRG) in a transient transfection system, using estrogen receptor (ER) and estrogen-responsive luciferase plasmids in MCF-7 cells. The extract activated both ERα and ERβ. KRG modulated the mRNA levels of estrogen-responsive genes such as pS2 and ESR1 and decreased the protein level of ERα. In order to examine in vivo estrogenic activity of KRG, sixteen female Sprague-Dawley rats separated into four groups were studied for nine weeks: non-ovariectomized (OVX) rats treated with olive oil, OVX rats treated with olive oil, OVX rats treated with 17-β-estradiol (E2) in olive oil, and OVX rats treated with KRG extract in olive oil. The experiments were repeated for three times and the data of twelve rats were combined. Body weight of OVX rats was greater than that of sham-operated control rats and was decreased by E2 treatment. Uterine weight increased after E2 treatment compared to OVX rats. However, no difference in body or uterine weight was observed with KRG intake. KRG induced reductions in total cholesterol, low density lipoprotein cholesterol/total cholesterol, high density lipoprotein cholesterol/total cholesterol, and low density lipoprotein cholesterol/high density lipoprotein cholesterol, but not to the same degree as did E2 intake. These results show that KRG does contain estrogenic activity as manifested by in vitro study but the activity is not strong enough to elicit physiological responses.
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Affiliation(s)
- Myeong Kuk Shim
- Department of Bioscience and Biotechnology, Institute of Biotechnology, College of Life Science, Sejong University, Seoul 143-747, Korea
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46
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Budworth H, McMurray CT. Bidirectional transcription of trinucleotide repeats: roles for excision repair. DNA Repair (Amst) 2013; 12:672-84. [PMID: 23669397 DOI: 10.1016/j.dnarep.2013.04.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Genomic instability at repetitive DNA regions in cells of the nervous system leads to a number of neurodegenerative and neuromuscular diseases, including those with an expanded trinucleotide repeat (TNR) tract at or nearby an expressed gene. Expansion causes disease when a particular base sequence is repeated beyond the normal range, interfering with the expression or properties of a gene product. Disease severity and onset depend on the number of repeats. As the length of the repeat tract grows, so does the size of the successive expansions and the likelihood of another unstable event. In fragile X syndrome, for example, CGG repeat instability and pathogenesis are not typically observed below tracts of roughly 50 repeats, but occur frequently at or above 55 repeats, and are virtually certain above 100-300 repeats. Recent evidence points to bidirectional transcription as a new aspect of TNR instability and pathophysiology. Bidirectional transcription of TNR genes produces novel proteins and/or regulatory RNAs that influence both toxicity and epigenetic changes in TNR promoters. Bidirectional transcription of the TNR tract appears to influence aspects of its stability, gene processing, splicing, gene silencing, and chemical modification of DNAs. Paradoxically, however, some of the same effects are observed on both the expanded TNR gene and on its normal gene counterpart. In this review, we discuss the possible normal and abnormal effects of bidirectional transcription on trinucleotide repeat instability, the role of DNA repair in causing, preventing, or maintaining methylation, and chromatin environment of TNR genes.
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Affiliation(s)
- Helen Budworth
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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47
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Hervouet E, Cartron PF, Jouvenot M, Delage-Mourroux R. Epigenetic regulation of estrogen signaling in breast cancer. Epigenetics 2013; 8:237-45. [PMID: 23364277 PMCID: PMC3669116 DOI: 10.4161/epi.23790] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Estrogen signaling is mediated by ERα and ERβ in hormone dependent, breast cancer (BC). Over the last decade the implication of epigenetic pathways in BC tumorigenesis has emerged: cancer-related epigenetic modifications are implicated in both gene expression regulation, and chromosomal instability. In this review, the epigenetic-mediated estrogen signaling, controlling both ER level and ER-targeted gene expression in BC, are discussed: (1) ER silencing is frequently observed in BC and is often associated with epigenetic regulations while chemical epigenetic modulators restore ER expression and increase response to treatment;(2) ER-targeted gene expression is tightly regulated by co-recruitment of ER and both coactivators/corepressors including HATs, HDACs, HMTs, Dnmts and Polycomb proteins.
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Affiliation(s)
- Eric Hervouet
- Université de Franche-Comté, Laboratoire de Biochimie, EA3922, Expression Génique et Pathologies du Système Nerveux Central, SFRIBCT FED 4234, UFR Sciences et Techniques, Besançon, France.
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48
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Abstract
DNA methylation has long been considered a very stable DNA modification in mammals that could only be removed by replication in the absence of remethylation - that is, by mere dilution of this epigenetic mark (so-called passive DNA demethylation). However, in recent years, a significant number of studies have revealed the existence of active processes of DNA demethylation in mammals, with important roles in development and transcriptional regulation, allowing the molecular mechanisms of active DNA demethylation to be unraveled. In this article, we review the recent literature highlighting the prominent role played in active DNA demethylation by base excision repair and especially by TDG.
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Affiliation(s)
- Shannon R Dalton
- Cancer Biology Program, Epigenetics & Progenitor Cells Program, Fox Chase Cancer Center, PA 19111, USA
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49
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Polyakova O, Borman S, Grimley R, Vamathevan J, Hayes B, Solari R. Identification of novel interacting partners of Sirtuin6. PLoS One 2012; 7:e51555. [PMID: 23240041 PMCID: PMC3519869 DOI: 10.1371/journal.pone.0051555] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 11/01/2012] [Indexed: 02/01/2023] Open
Abstract
SIRT6 is a member of the Sirtuin family of histone deacetylases that has been implicated in inflammatory, aging and metabolic pathways. Some of its actions have been suggested to be via physical interaction with NFκB and HIF1α and transcriptional regulation through its histone deacetylase activity. Our previous studies have investigated the histone deacetylase activity of SIRT6 and explored its ability to regulate the transcriptional responses to an inflammatory stimulus such as TNFα. In order to develop a greater understanding of SIRT6 function we have sought to identify SIRT6 interacting proteins by both yeast-2-hybrid and co-immunoprecipitation studies. We report a number of interacting partners which strengthen previous findings that SIRT6 functions in base excision repair (BER), and novel interactors which suggest a role in nucleosome and chromatin remodeling, the cell cycle and NFκB biology.
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Affiliation(s)
- Oxana Polyakova
- Platform Technology Sciences, GlaxoSmithKline, Stevenage, Hertfordshire, United Kingdom
| | - Satty Borman
- Platform Technology Sciences, GlaxoSmithKline, Stevenage, Hertfordshire, United Kingdom
| | - Rachel Grimley
- Platform Technology Sciences, GlaxoSmithKline, Stevenage, Hertfordshire, United Kingdom
| | - Jessica Vamathevan
- Computational Biology, GlaxoSmithKline, Stevenage, Hertfordshire, United Kingdom
| | - Brian Hayes
- Allergic Inflammation Discovery Performance Unit, GlaxoSmithKline, Stevenage, Hertfordshire, United Kingdom
| | - Roberto Solari
- Allergic Inflammation Discovery Performance Unit, GlaxoSmithKline, Stevenage, Hertfordshire, United Kingdom
- * E-mail:
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50
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Zhang H, Zhu JK. Active DNA demethylation in plants and animals. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2012. [PMID: 23197304 DOI: 10.1101/sqb.2012.77.014936] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Active DNA demethylation regulates many vital biological processes, including early development and locus-specific gene expression in plants and animals. In Arabidopsis, bifunctional DNA glycosylases directly excise the 5-methylcytosine base and then cleave the DNA backbone at the abasic site. Recent evidence suggests that mammals utilize DNA glycosylases after 5-methylcytosine is oxidized and/or deaminated. In both cases, the resultant single-nucleotide gap is subsequently filled with an unmodified cytosine through the DNA base excision repair pathway. The enzymatic removal of 5-methylcytosine is tightly integrated with histone modifications and possibly noncoding RNAs. Future research will increase our understanding of the mechanisms and critical roles of active DNA demethylation in various cellular processes as well as inspire novel genetic and chemical therapies for epigenetic disorders.
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Affiliation(s)
- H Zhang
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907, USA
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