1
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Abugable AA, Antar S, El-Khamisy SF. Chromosomal single-strand break repair and neurological disease: Implications on transcription and emerging genomic tools. DNA Repair (Amst) 2024; 135:103629. [PMID: 38266593 DOI: 10.1016/j.dnarep.2024.103629] [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: 10/14/2023] [Revised: 12/21/2023] [Accepted: 01/04/2024] [Indexed: 01/26/2024]
Abstract
Cells are constantly exposed to various sources of DNA damage that pose a threat to their genomic integrity. One of the most common types of DNA breaks are single-strand breaks (SSBs). Mutations in the repair proteins that are important for repairing SSBs have been reported in several neurological disorders. While several tools have been utilised to investigate SSBs in cells, it was only through recent advances in genomics that we are now beginning to understand the architecture of the non-random distribution of SSBs and their impact on key cellular processes such as transcription and epigenetic remodelling. Here, we discuss our current understanding of the genome-wide distribution of SSBs, their link to neurological disorders and summarise recent technologies to investigate SSBs at the genomic level.
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Affiliation(s)
- Arwa A Abugable
- School of Biosciences, Firth Court, University of Sheffield, Sheffield, UK; The healthy Lifespan and Neuroscience Institutes, University of Sheffield, Sheffield, UK
| | - Sarah Antar
- School of Biosciences, Firth Court, University of Sheffield, Sheffield, UK; The healthy Lifespan and Neuroscience Institutes, University of Sheffield, Sheffield, UK; Medical Biochemistry and Molecular Biology Department, Faculty of Medicine, Mansoura University, Egypt
| | - Sherif F El-Khamisy
- School of Biosciences, Firth Court, University of Sheffield, Sheffield, UK; The healthy Lifespan and Neuroscience Institutes, University of Sheffield, Sheffield, UK; Institute of Cancer Therapeutics, Faculty of Life Sciences, University of Bradford, Bradford, UK.
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2
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Pan L, Boldogh I. The potential for OGG1 inhibition to be a therapeutic strategy for pulmonary diseases. Expert Opin Ther Targets 2024; 28:117-130. [PMID: 38344773 PMCID: PMC11111349 DOI: 10.1080/14728222.2024.2317900] [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: 08/14/2023] [Accepted: 02/07/2024] [Indexed: 02/15/2024]
Abstract
INTRODUCTION Pulmonary diseases impose a daunting burden on healthcare systems and societies. Current treatment approaches primarily address symptoms, underscoring the urgency for the development of innovative pharmaceutical solutions. A noteworthy focus lies in targeting enzymes recognizing oxidatively modified DNA bases within gene regulatory elements, given their pivotal role in governing gene expression. AREAS COVERED This review delves into the intricate interplay between the substrate-specific binding of 8-oxoguanine DNA glycosylase 1 (OGG1) and epigenetic regulation, with a focal point on elucidating the molecular underpinnings and their biological implications. The absence of OGG1 distinctly attenuates the binding of transcription factors to cis elements, thereby modulating pro-inflammatory or pro-fibrotic transcriptional activity. Through a synergy of experimental insights gained from cell culture studies and murine models, utilizing prototype OGG1 inhibitors (O8, TH5487, and SU0268), a promising panorama emerges. These investigations underscore the absence of cytotoxicity and the establishment of a favorable tolerance profile for these OGG1 inhibitors. EXPERT OPINION Thus, the strategic targeting of the active site pocket of OGG1 through the application of small molecules introduces an innovative trajectory for advancing redox medicine. This approach holds particular significance in the context of pulmonary diseases, offering a refined avenue for their management.
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Affiliation(s)
- Lang Pan
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Istvan Boldogh
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555, USA
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3
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Valle-Orero J, Rieu M, Allemand JF, Bujaa D, Joubert A, Tran PLT, Croquette V, Boulé JB. Observing G4 formation and its resolution by Pif1 in real time by manipulation under magnetic tweezers. Methods Enzymol 2024; 695:119-158. [PMID: 38521583 DOI: 10.1016/bs.mie.2023.12.012] [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] [Indexed: 03/25/2024]
Abstract
G-quadruplexes (G4s) are nucleic acids secondary structures that may form in guanine-rich sequences, either intra or inter-molecularly. Ability of a primary sequence to form a G4 can be predicted computationally with an improving accuracy as well as tested in bulk using biophysical measurements. As a result, G4 density maps have been devised for a large number of genomes from all life kingdoms. Experimental validation of the formation of G4s in vivo however remains indirect and relies on their stabilization with small molecules, antibodies or proteins, or mutational studies, in order to measure downstream effects on gene expression or genome stability for example. Although numerous techniques exist to observe spontaneous formation of G4s in single-stranded DNA, observing G4 formation in double-stranded DNA (dsDNA) is more challenging. However, it is particularly relevant to understand if a given G4 sequence forms stably in a dsDNA context, if it is stable enough to dock proteins or pose a challenge to molecular motors such as helicases or polymerases. In essence, G4s can be a threat to genomic stability but carry as well as the potential to be elements of a structural language in the non-replicating genome. To study quantitatively the formation dynamics and stability of single intramolecular G4s embedded in dsDNA, we have adapted techniques of DNA manipulation under magnetic tweezers. This technique also allows to study encounters of molecular motors with G4 at a single molecule resolution, in order to gain insight into the specificity of G4 resolution by molecular motors, and its efficiency. The procedures described here include the design of the G4 substrate, the study of G4 formation probability and lifetime in dsDNA, as well as procedures to characterize the encounter between the Pif1 helicase and a G4 until G4 resolution. The procedures that we described here can easily be extended to the study of other G4s or molecular motors.
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Affiliation(s)
- Jessica Valle-Orero
- Physics Laboratory of the École Normale Supérieure, CNRS, ENS, PSL University, Sorbonne University, Paris-Cité University, Paris, France; Biology Institute of the École Normale Supérieure (IBENS), ENS, CNRS, INSERM, PSL University, Paris, France; Department of Computer Science, Mathematics and Environmental Sciences, The American University of Paris, Paris, France.
| | - Martin Rieu
- Physics Laboratory of the École Normale Supérieure, CNRS, ENS, PSL University, Sorbonne University, Paris-Cité University, Paris, France; Biology Institute of the École Normale Supérieure (IBENS), ENS, CNRS, INSERM, PSL University, Paris, France; Department of Physics, University of Oxford, Oxford, United Kingdom
| | - Jean-François Allemand
- Physics Laboratory of the École Normale Supérieure, CNRS, ENS, PSL University, Sorbonne University, Paris-Cité University, Paris, France; Biology Institute of the École Normale Supérieure (IBENS), ENS, CNRS, INSERM, PSL University, Paris, France
| | - Dulamkhuu Bujaa
- Physics Laboratory of the École Normale Supérieure, CNRS, ENS, PSL University, Sorbonne University, Paris-Cité University, Paris, France; Biology Institute of the École Normale Supérieure (IBENS), ENS, CNRS, INSERM, PSL University, Paris, France
| | - Alexandra Joubert
- Genome Structure and Instability Laboratory, National Museum of Natural History, CNRS, INSERM, Sorbonne University Alliance, Paris, France
| | - Phong Lan Thao Tran
- Genome Structure and Instability Laboratory, National Museum of Natural History, CNRS, INSERM, Sorbonne University Alliance, Paris, France; Depixus SAS, 3-5 impasse Reille, Paris, France
| | - Vincent Croquette
- Physics Laboratory of the École Normale Supérieure, CNRS, ENS, PSL University, Sorbonne University, Paris-Cité University, Paris, France; Biology Institute of the École Normale Supérieure (IBENS), ENS, CNRS, INSERM, PSL University, Paris, France; ESPCI Paris, PSL University, Paris, France.
| | - Jean-Baptiste Boulé
- Genome Structure and Instability Laboratory, National Museum of Natural History, CNRS, INSERM, Sorbonne University Alliance, Paris, France.
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4
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Vlahopoulos S, Pan L, Varisli L, Dancik GM, Karantanos T, Boldogh I. OGG1 as an Epigenetic Reader Affects NFκB: What This Means for Cancer. Cancers (Basel) 2023; 16:148. [PMID: 38201575 PMCID: PMC10778025 DOI: 10.3390/cancers16010148] [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: 11/22/2023] [Revised: 12/16/2023] [Accepted: 12/25/2023] [Indexed: 01/12/2024] Open
Abstract
8-oxoguanine glycosylase 1 (OGG1), which was initially identified as the enzyme that catalyzes the first step in the DNA base excision repair pathway, is now also recognized as a modulator of gene expression. What is important for cancer is that OGG1 acts as a modulator of NFκB-driven gene expression. Specifically, oxidant stress in the cell transiently halts enzymatic activity of substrate-bound OGG1. The stalled OGG1 facilitates DNA binding of transactivators, such as NFκB to their cognate sites, enabling the expression of cytokines and chemokines, with ensuing recruitment of inflammatory cells. Recently, we highlighted chief aspects of OGG1 involvement in regulation of gene expression, which hold significance in lung cancer development. However, OGG1 has also been implicated in the molecular underpinning of acute myeloid leukemia. This review analyzes and discusses how these cells adapt through redox-modulated intricate connections, via interaction of OGG1 with NFκB, which provides malignant cells with alternative molecular pathways to transform their microenvironment, enabling adjustment, promoting cell proliferation, metastasis, and evading killing by therapeutic agents.
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Affiliation(s)
- Spiros Vlahopoulos
- First Department of Pediatrics, National and Kapodistrian University of Athens, Thivon & Levadeias 8, Goudi, 11527 Athens, Greece
| | - Lang Pan
- Department of Microbiology and Immunology, School of Medicine, University of Texas Medical Branch at Galveston, 301 University Blvd., Galveston, TX 77555, USA;
| | - Lokman Varisli
- Department of Molecular Biology and Genetics, Science Faculty, Dicle University, Diyarbakir 21280, Turkey;
| | - Garrett M. Dancik
- Department of Computer Science, Eastern Connecticut State University, Willimantic, CT 06226, USA;
| | - Theodoros Karantanos
- Division of Hematological Malignancies, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21218, USA;
| | - Istvan Boldogh
- Department of Microbiology and Immunology, School of Medicine, University of Texas Medical Branch at Galveston, 301 University Blvd., Galveston, TX 77555, USA;
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5
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Neupane A, Chariker JH, Rouchka EC. Analysis of Nucleotide Variations in Human G-Quadruplex Forming Regions Associated with Disease States. Genes (Basel) 2023; 14:2125. [PMID: 38136947 PMCID: PMC10742762 DOI: 10.3390/genes14122125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/20/2023] [Accepted: 11/23/2023] [Indexed: 12/24/2023] Open
Abstract
While the role of G quadruplex (G4) structures has been identified in cancers and metabolic disorders, single nucleotide variations (SNVs) and their effect on G4s in disease contexts have not been extensively studied. The COSMIC and CLINVAR databases were used to detect SNVs present in G4s to identify sequence level changes and their effect on the alteration of the G4 secondary structure. A total of 37,515 G4 SNVs in the COSMIC database and 2378 in CLINVAR were identified. Of those, 7236 COSMIC (19.3%) and 457 (19%) of the CLINVAR variants result in G4 loss, while 2728 (COSMIC) and 129 (CLINVAR) SNVs gain a G4 structure. The remaining variants potentially affect the folding energy without affecting the presence of a G4. Analysis of mutational patterns in the G4 structure shows a higher selective pressure (3-fold) in the coding region on the template strand compared to the reverse strand. At the same time, an equal proportion of SNVs were observed among intronic, promoter, and enhancer regions across strands.
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Affiliation(s)
- Aryan Neupane
- School of Graduate and Interdisciplinary Studies, University of Louisville, Louisville, KY 40292, USA;
| | - Julia H. Chariker
- Department of Neuroscience Training, University of Louisville, Louisville, KY 40292, USA;
- Kentucky IDeA Network of Biomedical Research Excellence (KY INBRE) Bioinformatics Core, University of Louisville, Louisville, KY 40292, USA
| | - Eric C. Rouchka
- Kentucky IDeA Network of Biomedical Research Excellence (KY INBRE) Bioinformatics Core, University of Louisville, Louisville, KY 40292, USA
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, KY 40292, USA
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6
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Malfatti MC, Bellina A, Antoniali G, Tell G. Revisiting Two Decades of Research Focused on Targeting APE1 for Cancer Therapy: The Pros and Cons. Cells 2023; 12:1895. [PMID: 37508559 PMCID: PMC10378182 DOI: 10.3390/cells12141895] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/06/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023] Open
Abstract
APE1 is an essential endodeoxyribonuclease of the base excision repair pathway that maintains genome stability. It was identified as a pivotal factor favoring tumor progression and chemoresistance through the control of gene expression by a redox-based mechanism. APE1 is overexpressed and serum-secreted in different cancers, representing a prognostic and predictive factor and a promising non-invasive biomarker. Strategies directly targeting APE1 functions led to the identification of inhibitors showing potential therapeutic value, some of which are currently in clinical trials. Interestingly, evidence indicates novel roles of APE1 in RNA metabolism that are still not fully understood, including its activity in processing damaged RNA in chemoresistant phenotypes, regulating onco-miRNA maturation, and oxidized RNA decay. Recent data point out a control role for APE1 in the expression and sorting of onco-miRNAs within secreted extracellular vesicles. This review is focused on giving a portrait of the pros and cons of the last two decades of research aiming at the identification of inhibitors of the redox or DNA-repair functions of APE1 for the definition of novel targeted therapies for cancer. We will discuss the new perspectives in cancer therapy emerging from the unexpected finding of the APE1 role in miRNA processing for personalized therapy.
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Affiliation(s)
- Matilde Clarissa Malfatti
- Laboratory of Molecular Biology and DNA Repair, Department of Medicine, University of Udine, 33100 Udine, Italy
| | - Alessia Bellina
- Laboratory of Molecular Biology and DNA Repair, Department of Medicine, University of Udine, 33100 Udine, Italy
| | - Giulia Antoniali
- Laboratory of Molecular Biology and DNA Repair, Department of Medicine, University of Udine, 33100 Udine, Italy
| | - Gianluca Tell
- Laboratory of Molecular Biology and DNA Repair, Department of Medicine, University of Udine, 33100 Udine, Italy
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7
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Neupane A, Chariker JH, Rouchka EC. Analysis of nucleotide variations in human g-quadruplex forming regions associated with disease states. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.30.526341. [PMID: 36778288 PMCID: PMC9915501 DOI: 10.1101/2023.01.30.526341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
While the role of G4 G quadruplex structures has been identified in cancers and metabolic disorders, single nucleotide variations (SNVs) and their effect on G4s in disease contexts have not been extensively studied. The COSMIC and CLINVAR databases were used to detect SNVs present in G4s to identify sequence level changes and their effect on alteration of G4 secondary structure. 37,515 G4 SNVs in the COSMIC database and 2,115 in CLINVAR were identified. Of those, 7,236 COSMIC (19.3%) and 416 (18%) of the CLINVAR variants result in G4 loss, while 2,728 (COSMIC) and 112 (CLINVAR) SNVs gain a G4 structure. The gene ontology term "GnRH (Gonadotropin-releasing hormone) secretion" is enriched in 21 genes in this pathway that have a G4 destabilizing SNV. Analysis of mutational patterns in the G4 structure show a higher selective pressure (3-fold) in the coding region on the template strand compared to the non-template strand. At the same time, an equal proportion of SNVs were observed among intronic, promoter and enhancer regions across strands. Using GO and pathway enrichment, genes with SNVs for G4 forming propensity in the coding region are enriched for Regulation of Ras protein signal transduction and Src homology 3 (SH3) domain binding.
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Affiliation(s)
- Aryan Neupane
- School of Graduate and Interdisciplinary Studies, University of Louisville, Louisville, Kentucky, 40202, United States of America
| | - Julia H. Chariker
- Department of Neuroscience Training, University of Louisville, Louisville, Kentucky, 40292, United States of America
- KY INBRE Bioinformatics Core, University of Louisville, Louisville, Kentucky, 40292, United States of America
| | - Eric C. Rouchka
- KY INBRE Bioinformatics Core, University of Louisville, Louisville, Kentucky, 40292, United States of America
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, Kentucky 40292, United States of America
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8
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OGG1 in the Kidney: Beyond Base Excision Repair. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:5774641. [PMID: 36620083 PMCID: PMC9822757 DOI: 10.1155/2022/5774641] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 12/07/2022] [Accepted: 12/08/2022] [Indexed: 01/01/2023]
Abstract
8-Oxoguanine DNA glycosylase (OGG1) is a repair protein for 8-oxoguanine (8-oxoG) in eukaryotic atopic DNA. Through the initial base excision repair (BER) pathway, 8-oxoG is recognized and excised, and subsequently, other proteins are recruited to complete the repair. OGG1 is primarily located in the cytoplasm and can enter the nucleus and mitochondria to repair damaged DNA or to exert epigenetic regulation of gene transcription. OGG1 is involved in a wide range of physiological processes, such as DNA repair, oxidative stress, inflammation, fibrosis, and autophagy. In recent years, studies have found that OGG1 plays an important role in the progression of kidney diseases through repairing DNA, inducing inflammation, regulating autophagy and other transcriptional regulation, and governing protein interactions and functions during disease and injury. In particular, the epigenetic effects of OGG1 in kidney disease have gradually attracted widespread attention. This study reviews the structure and biological functions of OGG1 and the regulatory mechanism of OGG1 in kidney disease. In addition, the possibility of OGG1 as a potential therapeutic target in kidney disease is discussed.
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9
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Hahm JY, Park J, Jang ES, Chi SW. 8-Oxoguanine: from oxidative damage to epigenetic and epitranscriptional modification. Exp Mol Med 2022; 54:1626-1642. [PMID: 36266447 PMCID: PMC9636213 DOI: 10.1038/s12276-022-00822-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 05/06/2022] [Accepted: 05/26/2022] [Indexed: 12/29/2022] Open
Abstract
In pathophysiology, reactive oxygen species control diverse cellular phenotypes by oxidizing biomolecules. Among these, the guanine base in nucleic acids is the most vulnerable to producing 8-oxoguanine, which can pair with adenine. Because of this feature, 8-oxoguanine in DNA (8-oxo-dG) induces a G > T (C > A) mutation in cancers, which can be deleterious and thus actively repaired by DNA repair pathways. 8-Oxoguanine in RNA (o8G) causes problems in aberrant quality and translational fidelity, thereby it is subjected to the RNA decay pathway. In addition to oxidative damage, 8-oxo-dG serves as an epigenetic modification that affects transcriptional regulatory elements and other epigenetic modifications. With the ability of o8G•A in base pairing, o8G alters structural and functional RNA-RNA interactions, enabling redirection of posttranscriptional regulation. Here, we address the production, regulation, and function of 8-oxo-dG and o8G under oxidative stress. Primarily, we focus on the epigenetic and epitranscriptional roles of 8-oxoguanine, which highlights the significance of oxidative modification in redox-mediated control of gene expression.
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Affiliation(s)
- Ja Young Hahm
- grid.222754.40000 0001 0840 2678Department of Life Sciences, Korea University, Seoul, 02481 Republic of Korea ,grid.222754.40000 0001 0840 2678Institute of Life Sciences and Biotechnology, Korea University, Seoul, 02481 Republic of Korea
| | - Jongyeun Park
- grid.222754.40000 0001 0840 2678Department of Life Sciences, Korea University, Seoul, 02481 Republic of Korea ,grid.222754.40000 0001 0840 2678Institute of Life Sciences and Biotechnology, Korea University, Seoul, 02481 Republic of Korea
| | - Eun-Sook Jang
- grid.222754.40000 0001 0840 2678Department of Life Sciences, Korea University, Seoul, 02481 Republic of Korea ,grid.222754.40000 0001 0840 2678Institute of Life Sciences and Biotechnology, Korea University, Seoul, 02481 Republic of Korea
| | - Sung Wook Chi
- grid.222754.40000 0001 0840 2678Department of Life Sciences, Korea University, Seoul, 02481 Republic of Korea ,grid.222754.40000 0001 0840 2678Institute of Life Sciences and Biotechnology, Korea University, Seoul, 02481 Republic of Korea ,grid.222754.40000 0001 0840 2678KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, 02481 Republic of Korea
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10
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Abstract
![]()
Oxidation of a guanine nucleotide in DNA yields an 8-oxoguanine
nucleotide (oxoG) and is a mutagenic event in the genome.
Due to different arrangements of hydrogen-bond donors and acceptors, oxoG can affect the secondary structure of nucleic acids. We
have investigated base pairing preferences of oxoG in the
core of a tetrahelical G-quadruplex structure, adopted by analogues
of d(TG4T). Using spectroscopic methods, we have shown
that G-quartets can be fully substituted with oxoG nucleobases
to form an oxoG-quartet with a revamped hydrogen-bonding
scheme. While an oxoG-quartet can be incorporated into
the G-quadruplex core without distorting the phosphodiester backbone,
larger dimensions of the central cavity change the cation localization
and exchange properties.
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Affiliation(s)
- Simon Aleksič
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.,Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia
| | - Peter Podbevšek
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Janez Plavec
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.,Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia.,EN-FIST Centre of Excellence, Trg OF 13, 1000 Ljubljana, Slovenia
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11
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Miclot T, Bignon E, Terenzi A, Grandemange S, Barone G, Monari A. G-Quadruplex Recognition by DARPIns through Epitope/Paratope Analogy. Chemistry 2022; 28:e202201824. [PMID: 35791808 PMCID: PMC9804223 DOI: 10.1002/chem.202201824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Indexed: 01/05/2023]
Abstract
We investigated the mechanisms leading to the specific recognition of Guanine Guadruplex (G4) by DARPins peptides, which can lead to the design of G4 s specific sensors. To this end we carried out all-atom molecular dynamic simulations to unravel the interactions between specific nucleic acids, including human-telomeric (h-telo), Bcl-2, and c-Myc, with different peptides, forming a DARPin/G4 complex. By comparing the sequences of DARPin with that of a peptide known for its high affinity for c-Myc, we show that the recognition cannot be ascribed to sequence similarity but, instead, depends on the complementarity between the three-dimensional arrangement of the molecular fragments involved: the α-helix/loops domain of DARPin and the G4 backbone. Our results reveal that DARPins tertiary structure presents a charged hollow region in which G4 can be hosted, thus the more complementary the structural shapes, the more stable the interaction.
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Affiliation(s)
- Tom Miclot
- Department of Biological, Chemical and Pharmaceutical Sciences and TechnologiesUniversità degli Studi di PalermoViale delle Scienze90128PalermoItaly,Université de Lorraine and CNRS LPCT UMR 701954000NancyFrance
| | | | - Alessio Terenzi
- Department of Biological, Chemical and Pharmaceutical Sciences and TechnologiesUniversità degli Studi di PalermoViale delle Scienze90128PalermoItaly
| | | | - Giampaolo Barone
- Department of Biological, Chemical and Pharmaceutical Sciences and TechnologiesUniversità degli Studi di PalermoViale delle Scienze90128PalermoItaly
| | - Antonio Monari
- Université de Lorraine and CNRS LPCT UMR 701954000NancyFrance,Université Paris Cité and CNRS, ITODYS75006ParisFrance
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12
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Akbari M, Nilsen HL, Montaldo NP. Dynamic features of human mitochondrial DNA maintenance and transcription. Front Cell Dev Biol 2022; 10:984245. [PMID: 36158192 PMCID: PMC9491825 DOI: 10.3389/fcell.2022.984245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/02/2022] [Indexed: 12/03/2022] Open
Abstract
Mitochondria are the primary sites for cellular energy production and are required for many essential cellular processes. Mitochondrial DNA (mtDNA) is a 16.6 kb circular DNA molecule that encodes only 13 gene products of the approximately 90 different proteins of the respiratory chain complexes and an estimated 1,200 mitochondrial proteins. MtDNA is, however, crucial for organismal development, normal function, and survival. MtDNA maintenance requires mitochondrially targeted nuclear DNA repair enzymes, a mtDNA replisome that is unique to mitochondria, and systems that control mitochondrial morphology and quality control. Here, we provide an overview of the current literature on mtDNA repair and transcription machineries and discuss how dynamic functional interactions between the components of these systems regulate mtDNA maintenance and transcription. A profound understanding of the molecular mechanisms that control mtDNA maintenance and transcription is important as loss of mtDNA integrity is implicated in normal process of aging, inflammation, and the etiology and pathogenesis of a number of diseases.
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Affiliation(s)
- Mansour Akbari
- Department of Medical Biology, Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Hilde Loge Nilsen
- Department of Clinical Molecular Biology, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Unit for precision medicine, Akershus University Hospital, Nordbyhagen, Norway
- Department of Microbiology, Oslo University Hospital, Oslo, Norway
| | - Nicola Pietro Montaldo
- Department of Clinical Molecular Biology, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- *Correspondence: Nicola Pietro Montaldo,
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13
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OGG1 in Lung—More than Base Excision Repair. Antioxidants (Basel) 2022; 11:antiox11050933. [PMID: 35624797 PMCID: PMC9138115 DOI: 10.3390/antiox11050933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 05/03/2022] [Accepted: 05/07/2022] [Indexed: 12/04/2022] Open
Abstract
As the organ executing gas exchange and directly facing the external environment, the lungs are challenged continuously by various stimuli, causing the disequilibration of redox homeostasis and leading to pulmonary diseases. The breakdown of oxidants/antioxidants system happens when the overproduction of free radicals results in an excess over the limitation of cleaning capability, which could lead to the oxidative modification of macromolecules including nucleic acids. The most common type of oxidative base, 8-oxoG, is considered the marker of DNA oxidative damage. The appearance of 8-oxoG could lead to base mismatch and its accumulation might end up as tumorigenesis. The base 8-oxoG was corrected by base excision repair initiated by 8-oxoguanine DNA glycosylase-1 (OGG1), which recognizes 8-oxoG from the genome and excises it from the DNA double strand, generating an AP site for further processing. Aside from its function in DNA damage repairment, it has been reported that OGG1 takes part in the regulation of gene expression, derived from its DNA binding characteristic, and showed impacts on inflammation. Researchers believe that OGG1 could be the potential therapy target for relative disease. This review intends to make an overall summary of the mechanism through which OGG1 regulates gene expression and the role of OGG1 in pulmonary diseases.
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14
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Allred DR. Integration of DNA Repair, Antigenic Variation, Cytoadhesion, and Chance in Babesia Survival: A Perspective. Front Cell Infect Microbiol 2022; 12:869696. [PMID: 35493746 PMCID: PMC9047050 DOI: 10.3389/fcimb.2022.869696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 03/24/2022] [Indexed: 11/13/2022] Open
Abstract
Apicomplexan parasites live in hostile environments in which they are challenged chemically and their hosts attempt in many ways to kill them. In response, the parasites have evolved multiple mechanisms that take advantage of these challenges to enhance their survival. Perhaps the most impressive example is the evolutionary co-option of DNA repair mechanisms by the parasites as a means to rapidly manipulate the structure, antigenicity, and expression of the products of specific multigene families. The purpose of variant proteins that mediate cytoadhesion has long been thought to be primarily the avoidance of splenic clearance. Based upon known biology, I present an alternative perspective in which it is survival of the oxidative environment within which Babesia spp. parasites live that has driven integration of DNA repair, antigenic variation, and cytoadhesion, and speculate on how genome organization affects that integration. This perspective has ramifications for the development of parasite control strategies.
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Affiliation(s)
- David R. Allred
- Department of Infectious Diseases and Immunology, University of Florida, Gainesville, FL, United States
- Genetics Institute, University of Florida, Gainesville, FL, United States
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
- *Correspondence: David R. Allred,
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15
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Kim S, Hwang S. G-Quadruplex Matters in Tissue-Specific Tumorigenesis by BRCA1 Deficiency. Genes (Basel) 2022; 13:genes13030391. [PMID: 35327946 PMCID: PMC8948836 DOI: 10.3390/genes13030391] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 12/14/2022] Open
Abstract
How and why distinct genetic alterations, such as BRCA1 mutation, promote tumorigenesis in certain tissues, but not others, remain an important issue in cancer research. The underlying mechanisms may reveal tissue-specific therapeutic vulnerabilities. Although the roles of BRCA1, such as DNA damage repair and stalled fork stabilization, obviously contribute to tumor suppression, these ubiquitously important functions cannot explain tissue-specific tumorigenesis by BRCA1 mutations. Recent advances in our understanding of the cancer genome and fundamental cellular processes on DNA, such as transcription and DNA replication, have provided new insights regarding BRCA1-associated tumorigenesis, suggesting that G-quadruplex (G4) plays a critical role. In this review, we summarize the importance of G4 structures in mutagenesis of the cancer genome and cell type-specific gene regulation, and discuss a recently revealed molecular mechanism of G4/base excision repair (BER)-mediated transcriptional activation. The latter adequately explains the correlation between the accumulation of unresolved transcriptional regulatory G4s and multi-level genomic alterations observed in BRCA1-associated tumors. In summary, tissue-specific tumorigenesis by BRCA1 deficiency can be explained by cell type-specific levels of transcriptional regulatory G4s and the role of BRCA1 in resolving it. This mechanism would provide an integrated understanding of the initiation and development of BRCA1-associated tumors.
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Affiliation(s)
- Sanghyun Kim
- Department of Biomedical Science, College of Life Science, CHA University, Sungnam 13488, Korea;
| | - Sohyun Hwang
- Department of Biomedical Science, College of Life Science, CHA University, Sungnam 13488, Korea;
- Department of Pathology, CHA Bundang Medical Center, CHA University School of Medicine, Sungnam 13496, Korea
- Correspondence:
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16
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Scala G, Gorini F, Ambrosio S, Chiariello AM, Nicodemi M, Lania L, Majello B, Amente S. OUP accepted manuscript. Nucleic Acids Res 2022; 50:3292-3306. [PMID: 35234932 PMCID: PMC8989568 DOI: 10.1093/nar/gkac143] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/12/2022] [Accepted: 02/15/2022] [Indexed: 11/25/2022] Open
Abstract
8-Oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG), a major product of the DNA oxidization process, has been proposed to have an epigenetic function in gene regulation and has been associated with genome instability. NGS-based methodologies are contributing to the characterization of the 8-oxodG function in the genome. However, the 8-oxodG epigenetic role at a genomic level and the mechanisms controlling the genomic 8-oxodG accumulation/maintenance have not yet been fully characterized. In this study, we report the identification and characterization of a set of enhancer regions accumulating 8-oxodG in human epithelial cells. We found that these oxidized enhancers are mainly super-enhancers and are associated with bidirectional-transcribed enhancer RNAs and DNA Damage Response activation. Moreover, using ChIA-PET and HiC data, we identified specific CTCF-mediated chromatin loops in which the oxidized enhancer and promoter regions physically associate. Oxidized enhancers and their associated chromatin loops accumulate endogenous double-strand breaks which are in turn repaired by NHEJ pathway through a transcription-dependent mechanism. Our work suggests that 8-oxodG accumulation in enhancers–promoters pairs occurs in a transcription-dependent manner and provides novel mechanistic insights on the intrinsic fragility of chromatin loops containing oxidized enhancers-promoters interactions.
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Affiliation(s)
- Giovanni Scala
- Department of Biology, University of Naples ‘Federico II’, Naples, Italy
| | - Francesca Gorini
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples ‘Federico II’, Naples, Italy
| | - Susanna Ambrosio
- Department of Biology, University of Naples ‘Federico II’, Naples, Italy
| | - Andrea M Chiariello
- Department of Physics, University of Naples Federico II, and INFN, Naples, Italy
| | - Mario Nicodemi
- Department of Physics, University of Naples Federico II, and INFN, Naples, Italy
| | - Luigi Lania
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples ‘Federico II’, Naples, Italy
| | - Barbara Majello
- Correspondence may also be addressed to Barbara Majello. Tel: +39 081 679062;
| | - Stefano Amente
- To whom correspondence should be addressed. Tel: +39 081 7463044;
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17
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de Sousa MML, Ye J, Luna L, Hildrestrand G, Bjørås K, Scheffler K, Bjørås M. Impact of Oxidative DNA Damage and the Role of DNA Glycosylases in Neurological Dysfunction. Int J Mol Sci 2021; 22:12924. [PMID: 34884729 PMCID: PMC8657561 DOI: 10.3390/ijms222312924] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 11/25/2021] [Accepted: 11/27/2021] [Indexed: 11/16/2022] Open
Abstract
The human brain requires a high rate of oxygen consumption to perform intense metabolic activities, accounting for 20% of total body oxygen consumption. This high oxygen uptake results in the generation of free radicals, including reactive oxygen species (ROS), which, at physiological levels, are beneficial to the proper functioning of fundamental cellular processes. At supraphysiological levels, however, ROS and associated lesions cause detrimental effects in brain cells, commonly observed in several neurodegenerative disorders. In this review, we focus on the impact of oxidative DNA base lesions and the role of DNA glycosylase enzymes repairing these lesions on brain function and disease. Furthermore, we discuss the role of DNA base oxidation as an epigenetic mechanism involved in brain diseases, as well as potential roles of DNA glycosylases in different epigenetic contexts. We provide a detailed overview of the impact of DNA glycosylases on brain metabolism, cognition, inflammation, tissue loss and regeneration, and age-related neurodegenerative diseases based on evidence collected from animal and human models lacking these enzymes, as well as post-mortem studies on patients with neurological disorders.
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Affiliation(s)
- Mirta Mittelstedt Leal de Sousa
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, 7028 Trondheim, Norway; (J.Y.); (K.B.)
| | - Jing Ye
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, 7028 Trondheim, Norway; (J.Y.); (K.B.)
| | - Luisa Luna
- Department of Microbiology, Oslo University Hospital, University of Oslo, Rikshospitalet, 0424 Oslo, Norway; (L.L.); (G.H.)
| | - Gunn Hildrestrand
- Department of Microbiology, Oslo University Hospital, University of Oslo, Rikshospitalet, 0424 Oslo, Norway; (L.L.); (G.H.)
| | - Karine Bjørås
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, 7028 Trondheim, Norway; (J.Y.); (K.B.)
| | - Katja Scheffler
- Department of Neurology, St. Olavs Hospital, 7006 Trondheim, Norway;
- Department of Laboratory Medicine, St. Olavs Hospital, 7006 Trondheim, Norway
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Magnar Bjørås
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, 7028 Trondheim, Norway; (J.Y.); (K.B.)
- Department of Microbiology, Oslo University Hospital, University of Oslo, Rikshospitalet, 0424 Oslo, Norway; (L.L.); (G.H.)
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18
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Grün JT, Schwalbe H. Folding dynamics of polymorphic G-quadruplex structures. Biopolymers 2021; 113:e23477. [PMID: 34664713 DOI: 10.1002/bip.23477] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/30/2021] [Accepted: 09/30/2021] [Indexed: 12/14/2022]
Abstract
G-quadruplexes (G4), found in numerous places within the human genome, are involved in essential processes of cell regulation. Chromosomal DNA G4s are involved for example, in replication and transcription as first steps of gene expression. Hence, they influence a plethora of downstream processes. G4s possess an intricate structure that differs from canonical B-form DNA. Identical DNA G4 sequences can adopt multiple long-lived conformations, a phenomenon known as G4 polymorphism. A detailed understanding of the molecular mechanisms that drive G4 folding is essential to understand their ambivalent regulatory roles. Disentangling the inherent dynamic and polymorphic nature of G4 structures thus is key to unravel their biological functions and make them amenable as molecular targets in novel therapeutic approaches. We here review recent experimental approaches to monitor G4 folding and discuss structural aspects for possible folding pathways. Substantial progress in the understanding of G4 folding within the recent years now allows drawing comprehensive models of the complex folding energy landscape of G4s that we herein evaluate based on computational and experimental evidence.
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Affiliation(s)
- J Tassilo Grün
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University, Frankfurt/M, Germany.,Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-University Frankfurt, Frankfurt/M, Germany
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19
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Effects of Manganese on Genomic Integrity in the Multicellular Model Organism Caenorhabditis elegans. Int J Mol Sci 2021; 22:ijms222010905. [PMID: 34681565 PMCID: PMC8535284 DOI: 10.3390/ijms222010905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 09/24/2021] [Accepted: 09/30/2021] [Indexed: 12/30/2022] Open
Abstract
Although manganese (Mn) is an essential trace element, overexposure is associated with Mn-induced toxicity and neurological dysfunction. Even though Mn-induced oxidative stress is discussed extensively, neither the underlying mechanisms of the potential consequences of Mn-induced oxidative stress on DNA damage and DNA repair, nor the possibly resulting toxicity are characterized yet. In this study, we use the model organism Caenorhabditis elegans to investigate the mode of action of Mn toxicity, focusing on genomic integrity by means of DNA damage and DNA damage response. Experiments were conducted to analyze Mn bioavailability, lethality, and induction of DNA damage. Different deletion mutant strains were then used to investigate the role of base excision repair (BER) and dePARylation (DNA damage response) proteins in Mn-induced toxicity. The results indicate a dose- and time-dependent uptake of Mn, resulting in increased lethality. Excessive exposure to Mn decreases genomic integrity and activates BER. Altogether, this study characterizes the consequences of Mn exposure on genomic integrity and therefore broadens the molecular understanding of pathways underlying Mn-induced toxicity. Additionally, studying the basal poly(ADP-ribosylation) (PARylation) of worms lacking poly(ADP-ribose) glycohydrolase (PARG) parg-1 or parg-2 (two orthologue of PARG), indicates that parg-1 accounts for most of the glycohydrolase activity in worms.
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20
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Burchat N, Sharma P, Ye H, Komakula SSB, Dobrzyn A, Vartanian V, Lloyd RS, Sampath H. Maternal Transmission of Human OGG1 Protects Mice Against Genetically- and Diet-Induced Obesity Through Increased Tissue Mitochondrial Content. Front Cell Dev Biol 2021; 9:718962. [PMID: 34604220 PMCID: PMC8480284 DOI: 10.3389/fcell.2021.718962] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 08/09/2021] [Indexed: 01/05/2023] Open
Abstract
Obesity and related metabolic disorders are pressing public health concerns, raising the risk for a multitude of chronic diseases. Obesity is multi-factorial disease, with both diet and lifestyle, as well as genetic and developmental factors leading to alterations in energy balance. In this regard, a novel role for DNA repair glycosylases in modulating risk for obesity has been previously established. Global deletion of either of two different glycosylases with varying substrate specificities, Nei-like endonuclease 1 (NEIL1) or 8-oxoguanine DNA glycosylase-1 (OGG1), both predispose mice to diet-induced obesity (DIO). Conversely, enhanced expression of the human OGG1 gene renders mice resistant to obesity and adiposity. This resistance to DIO is mediated through increases in whole body energy expenditure and increased respiration in adipose tissue. Here, we report that hOGG1 expression also confers resistance to genetically-induced obesity. While Agouti obese (Ay/a) mice are hyperphagic and consequently develop obesity on a chow diet, hOGG1 expression in Ay/a mice (Ay/aTg) prevents increased body weight, without reducing food intake. Instead, obesity resistance in Ay/aTg mice is accompanied by increased whole body energy expenditure and tissue mitochondrial content. We also report for the first time that OGG1-mediated obesity resistance in both the Ay/a model and DIO model requires maternal transmission of the hOGG1 transgene. Maternal, but not paternal, transmission of the hOGG1 transgene is associated with obesity resistance and increased mitochondrial content in adipose tissue. These data demonstrate a critical role for OGG1 in modulating energy balance through changes in adipose tissue function. They also demonstrate the importance of OGG1 in modulating developmental programming of mitochondrial content and quality, thereby determining metabolic outcomes in offspring.
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Affiliation(s)
- Natalie Burchat
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ, United States
| | - Priyanka Sharma
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ, United States
| | - Hong Ye
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ, United States
| | - Sai Santosh Babu Komakula
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ, United States.,Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Agnieszka Dobrzyn
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ, United States.,Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Vladimir Vartanian
- Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, Portland, OR, United States
| | - R Stephen Lloyd
- Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, Portland, OR, United States.,Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, United States
| | - Harini Sampath
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ, United States.,Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ, United States.,Center for Microbiome, Nutrition, and Health, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ, United States
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21
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Fleming AM, Burrows CJ. Oxidative stress-mediated epigenetic regulation by G-quadruplexes. NAR Cancer 2021; 3:zcab038. [PMID: 34541539 PMCID: PMC8445369 DOI: 10.1093/narcan/zcab038] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/20/2021] [Accepted: 09/06/2021] [Indexed: 02/06/2023] Open
Abstract
Many cancer-associated genes are regulated by guanine (G)-rich sequences that are capable of refolding from the canonical duplex structure to an intrastrand G-quadruplex. These same sequences are sensitive to oxidative damage that is repaired by the base excision repair glycosylases OGG1 and NEIL1–3. We describe studies indicating that oxidation of a guanosine base in a gene promoter G-quadruplex can lead to up- and downregulation of gene expression that is location dependent and involves the base excision repair pathway in which the first intermediate, an apurinic (AP) site, plays a key role mediated by AP endonuclease 1 (APE1/REF1). The nuclease activity of APE1 is paused at a G-quadruplex, while the REF1 capacity of this protein engages activating transcription factors such as HIF-1α, AP-1 and p53. The mechanism has been probed by in vitro biophysical studies, whole-genome approaches and reporter plasmids in cellulo. Replacement of promoter elements by a G-quadruplex sequence usually led to upregulation, but depending on the strand and precise location, examples of downregulation were also found. The impact of oxidative stress-mediated lesions in the G-rich sequence enhanced the effect, whether it was positive or negative.
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Affiliation(s)
- Aaron M Fleming
- Department of Chemistry, University of Utah, 315 S. 1400 East, Salt Lake City, UT 84112-0850, USA
| | - Cynthia J Burrows
- Department of Chemistry, University of Utah, 315 S. 1400 East, Salt Lake City, UT 84112-0850, USA
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22
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Ali A, Wang A, Ribeiro RVP, Beroncal EL, Baciu C, Galasso M, Gomes B, Mariscal A, Hough O, Brambate E, Abdelnour-Berchtold E, Michaelsen V, Zhang Y, Gazzalle A, Fan E, Brochard L, Yeung J, Waddell T, Liu M, Andreazza AC, Keshavjee S, Cypel M. Static lung storage at 10°C maintains mitochondrial health and preserves donor organ function. Sci Transl Med 2021; 13:eabf7601. [PMID: 34524862 DOI: 10.1126/scitranslmed.abf7601] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Aadil Ali
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Aizhou Wang
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Rafaela V P Ribeiro
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Erika L Beroncal
- Departments of Pharmacology & Toxicology and Psychiatry, The Canada Mitochondrial Network, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Cristina Baciu
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Marcos Galasso
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Bruno Gomes
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Andrea Mariscal
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Olivia Hough
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Edson Brambate
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Etienne Abdelnour-Berchtold
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Vinicius Michaelsen
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Yu Zhang
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Anajara Gazzalle
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Eddy Fan
- Divisions of Respirology and Critical Care Medicine, University Health Network, University of Toronto, Toronto, ON M5B 1W8, Canada
| | - Laurent Brochard
- Divisions of Respirology and Critical Care Medicine, University Health Network, University of Toronto, Toronto, ON M5B 1W8, Canada.,Keenan Research Centre, St Michael's Hospital, Unity Health Toronto and Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, M5B 1T8, Canada
| | - Jonathan Yeung
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada.,Division of Thoracic Surgery, Department of Surgery, University Health Network, University of Toronto, Toronto Lung Transplant Program, Toronto, ON M5G 2C4, Canada
| | - Tom Waddell
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada.,Division of Thoracic Surgery, Department of Surgery, University Health Network, University of Toronto, Toronto Lung Transplant Program, Toronto, ON M5G 2C4, Canada
| | - Mingyao Liu
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Ana C Andreazza
- Departments of Pharmacology & Toxicology and Psychiatry, The Canada Mitochondrial Network, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Shaf Keshavjee
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada.,Division of Thoracic Surgery, Department of Surgery, University Health Network, University of Toronto, Toronto Lung Transplant Program, Toronto, ON M5G 2C4, Canada
| | - Marcelo Cypel
- Latner Thoracic Surgery Research Laboratories, Toronto General Hospital Research Institute, University Health Network, Toronto, ON M5G 1L7, Canada.,Division of Thoracic Surgery, Department of Surgery, University Health Network, University of Toronto, Toronto Lung Transplant Program, Toronto, ON M5G 2C4, Canada
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23
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Robinson J, Raguseo F, Nuccio SP, Liano D, Di Antonio M. DNA G-quadruplex structures: more than simple roadblocks to transcription? Nucleic Acids Res 2021; 49:8419-8431. [PMID: 34255847 PMCID: PMC8421137 DOI: 10.1093/nar/gkab609] [Citation(s) in RCA: 119] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/01/2021] [Accepted: 07/05/2021] [Indexed: 12/12/2022] Open
Abstract
It has been >20 years since the formation of G-quadruplex (G4) secondary structures in gene promoters was first linked to the regulation of gene expression. Since then, the development of small molecules to selectively target G4s and their cellular application have contributed to an improved understanding of how G4s regulate transcription. One model that arose from this work placed these non-canonical DNA structures as repressors of transcription by preventing polymerase processivity. Although a considerable number of studies have recently provided sufficient evidence to reconsider this simplistic model, there is still a misrepresentation of G4s as transcriptional roadblocks. In this review, we will challenge this model depicting G4s as simple 'off switches' for gene expression by articulating how their formation has the potential to alter gene expression at many different levels, acting as a key regulatory element perturbing the nature of epigenetic marks and chromatin architecture.
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Affiliation(s)
- Jenna Robinson
- Imperial College London, Chemistry Department, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
- Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
| | - Federica Raguseo
- Imperial College London, Chemistry Department, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
- Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
| | - Sabrina Pia Nuccio
- Imperial College London, Chemistry Department, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
- Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
| | - Denise Liano
- Imperial College London, Chemistry Department, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
- Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
| | - Marco Di Antonio
- Imperial College London, Chemistry Department, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
- Institute of Chemical Biology, Molecular Sciences Research Hub, 82 Wood Lane, London W12 0BZ, UK
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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24
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Pavlova AV, Kubareva EA, Monakhova MV, Zvereva MI, Dolinnaya NG. Impact of G-Quadruplexes on the Regulation of Genome Integrity, DNA Damage and Repair. Biomolecules 2021; 11:1284. [PMID: 34572497 PMCID: PMC8472537 DOI: 10.3390/biom11091284] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/19/2021] [Accepted: 08/25/2021] [Indexed: 12/13/2022] Open
Abstract
DNA G-quadruplexes (G4s) are known to be an integral part of the complex regulatory systems in both normal and pathological cells. At the same time, the ability of G4s to impede DNA replication plays a critical role in genome integrity. This review summarizes the results of recent studies of G4-mediated genomic and epigenomic instability, together with associated DNA damage and repair processes. Although the underlying mechanisms remain to be elucidated, it is known that, among the proteins that recognize G4 structures, many are linked to DNA repair. We analyzed the possible role of G4s in promoting double-strand DNA breaks, one of the most deleterious DNA lesions, and their repair via error-prone mechanisms. The patterns of G4 damage, with a focus on the introduction of oxidative guanine lesions, as well as their removal from G4 structures by canonical repair pathways, were also discussed together with the effects of G4s on the repair machinery. According to recent findings, there must be a delicate balance between G4-induced genome instability and G4-promoted repair processes. A broad overview of the factors that modulate the stability of G4 structures in vitro and in vivo is also provided here.
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Affiliation(s)
- Anzhela V. Pavlova
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (M.I.Z.); (N.G.D.)
| | - Elena A. Kubareva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (E.A.K.); (M.V.M.)
| | - Mayya V. Monakhova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (E.A.K.); (M.V.M.)
| | - Maria I. Zvereva
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (M.I.Z.); (N.G.D.)
| | - Nina G. Dolinnaya
- Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia; (M.I.Z.); (N.G.D.)
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25
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Müller N, Khobta A. Regulation of GC box activity by 8-oxoguanine. Redox Biol 2021; 43:101997. [PMID: 33965877 PMCID: PMC8120935 DOI: 10.1016/j.redox.2021.101997] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/25/2021] [Accepted: 04/26/2021] [Indexed: 02/08/2023] Open
Abstract
The oxidation-induced DNA modification 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) was recently implicated in the activation and repression of gene transcription. We aimed at a systematic characterisation of the impacts of 8-oxodG on the activity of a GC box placed upstream from the RNA polymerase II core promoter. With the help of reporters carrying single synthetic 8-oxodG residues at four conserved G:C base pairs (underlined) within the 5'-TGGGCGGAGC-3' GC box sequence, we identified two modes of interference of 8-oxodG with the promoter activity. Firstly, 8-oxodG in the purine-rich (but not in the pyrimidine-rich) strand caused direct impairment of transcriptional activation. In addition, and independently of the first mechanism, 8-oxodG initiated a decline of the gene expression, which was mediated by the specific DNA glycosylase OGG1. For the different 8-oxodG positions, the magnitude of this effect reflected the excision preferences of OGG1. Thus, 8-oxodG seeded in the pyrimidine-rich strand was excised with the highest efficiency and caused the most pronounced decrease of the promoter activity. Conversely, 8-oxodG in the symmetric position within the same CpG dinucleotide, was poorly excised and induced no decline of the gene expression. Of note, abasic lesions caused gene silencing in both positions. By contrast, an uncleavable apurinic lesion in the pyrimidine-rich strand enhanced the GC box activity, suggesting that the AP endonuclease step provides a switch between the active versus repressed promoter states during base excision repair.
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Affiliation(s)
- Nadine Müller
- Unit "Responses to DNA Lesions", Institute of Toxicology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, 55131, Germany
| | - Andriy Khobta
- Unit "Responses to DNA Lesions", Institute of Toxicology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, 55131, Germany; Institute of Nutritional Science, University of Jena, Jena, 07743, Germany.
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26
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Salsbury AM, Lemkul JA. Cation competition and recruitment around the c-kit1 G-quadruplex using polarizable simulations. Biophys J 2021; 120:2249-2261. [PMID: 33794153 PMCID: PMC8390831 DOI: 10.1016/j.bpj.2021.03.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/22/2021] [Accepted: 03/25/2021] [Indexed: 11/24/2022] Open
Abstract
Nucleic acid-ion interactions are fundamentally important to the physical, energetic, and conformational properties of DNA and RNA. These interactions help fold and stabilize highly ordered secondary and tertiary structures, such as G-quadruplexes (GQs), which are functionally relevant in telomeres, replication initiation sites, and promoter sequences. The c-kit proto-oncogene encodes for a receptor tyrosine kinase and is linked to gastrointestinal stromal tumors, mast cell disease, and leukemia. This gene contains three unique GQ-forming sequences that have proposed antagonistic effects on gene expression. The dominant GQ, denoted c-kit1, has been shown to decrease expression of c-kit transcripts, making the c-kit1 GQ a promising drug target. Toward disease intervention, more information is needed regarding its conformational dynamics and ion binding properties. Therefore, we performed molecular dynamics simulations of the c-kit1 GQ with K+, Na+, Li+, and mixed salt solutions using the Drude-2017 polarizable force field. We evaluated GQ structure, ion sampling, core energetics, ion dehydration and binding, and ion competition and found that each analysis supported the known GQ-ion specificity trend (K+ > Na+ > Li+). We also found that K+ ions coordinate in the tetrad core antiprismatically, whereas Na+ and Li+ align coplanar to guanine tetrads, partially because of their attraction to surrounding water. Further, we showed that K+ occupancy is higher around the c-kit1 GQ and its nucleobases than Na+ and Li+, which tend to interact with backbone and sugar moieties. Finally, we showed that K+ binding to the c-kit1 GQ is faster and more frequent than Na+ and Li+. Such descriptions of GQ-ion dynamics suggest the rate of dehydration as the dominant factor for preference of K+ by DNA GQs and provide insight into noncanonical nucleic acids for which little experimental data exist.
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Affiliation(s)
| | - Justin A Lemkul
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia; Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia.
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27
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Sengupta P, Bose D, Chatterjee S. The Molecular Tête-à-Tête between G-Quadruplexes and the i-motif in the Human Genome. Chembiochem 2021; 22:1517-1537. [PMID: 33355980 DOI: 10.1002/cbic.202000703] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/16/2020] [Indexed: 12/22/2022]
Abstract
G-Quadruplex (GQ) and i-motif structures are the paradigmatic examples of nonclassical tetrastranded nucleic acids having multifarious biological functions and widespread applications in therapeutics and material science. Recently, tetraplexes emerged as promising anticancer targets due to their structural robustness, gene-regulatory roles, and predominant distribution at specific loci of oncogenes. However, it is arguable whether the i-motif evolves in the complementary single-stranded region after GQ formation in its opposite strand and vice versa. In this review, we address the prerequisites and significance of the simultaneous and/or mutually exclusive formation of GQ and i-motif structures at complementary and sequential positions in duplexes in the cellular milieu. We discussed how their dynamic interplay Sets up cellular homeostasis and exacerbates carcinogenesis. The review gives insights into the spatiotemporal formation of GQ and i-motifs that could be harnessed to design different types of reporter systems and diagnostic platforms for potential bioanalytical and therapeutic intervention.
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Affiliation(s)
- Pallabi Sengupta
- Department of Biophysics, Bose Institute, Centenary Campus, P-1/12, C.I.T. Scheme VIIM, Kankurgachi, Kolkata, 700054, West Bengal, India
| | - Debopriya Bose
- Department of Biophysics, Bose Institute, Centenary Campus, P-1/12, C.I.T. Scheme VIIM, Kankurgachi, Kolkata, 700054, West Bengal, India
| | - Subhrangsu Chatterjee
- Department of Biophysics, Bose Institute, Centenary Campus, P-1/12, C.I.T. Scheme VIIM, Kankurgachi, Kolkata, 700054, West Bengal, India
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28
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Malfatti MC, Antoniali G, Codrich M, Burra S, Mangiapane G, Dalla E, Tell G. New perspectives in cancer biology from a study of canonical and non-canonical functions of base excision repair proteins with a focus on early steps. Mutagenesis 2021; 35:129-149. [PMID: 31858150 DOI: 10.1093/mutage/gez051] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 12/05/2019] [Indexed: 12/15/2022] Open
Abstract
Alterations of DNA repair enzymes and consequential triggering of aberrant DNA damage response (DDR) pathways are thought to play a pivotal role in genomic instabilities associated with cancer development, and are further thought to be important predictive biomarkers for therapy using the synthetic lethality paradigm. However, novel unpredicted perspectives are emerging from the identification of several non-canonical roles of DNA repair enzymes, particularly in gene expression regulation, by different molecular mechanisms, such as (i) non-coding RNA regulation of tumour suppressors, (ii) epigenetic and transcriptional regulation of genes involved in genotoxic responses and (iii) paracrine effects of secreted DNA repair enzymes triggering the cell senescence phenotype. The base excision repair (BER) pathway, canonically involved in the repair of non-distorting DNA lesions generated by oxidative stress, ionising radiation, alkylation damage and spontaneous or enzymatic deamination of nucleotide bases, represents a paradigm for the multifaceted roles of complex DDR in human cells. This review will focus on what is known about the canonical and non-canonical functions of BER enzymes related to cancer development, highlighting novel opportunities to understand the biology of cancer and representing future perspectives for designing new anticancer strategies. We will specifically focus on APE1 as an example of a pleiotropic and multifunctional BER protein.
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Affiliation(s)
- Matilde Clarissa Malfatti
- Laboratory of Molecular Biology and DNA repair, Department of Medicine (DAME), University of Udine, Udine, Italy
| | - Giulia Antoniali
- Laboratory of Molecular Biology and DNA repair, Department of Medicine (DAME), University of Udine, Udine, Italy
| | - Marta Codrich
- Laboratory of Molecular Biology and DNA repair, Department of Medicine (DAME), University of Udine, Udine, Italy
| | - Silvia Burra
- Laboratory of Molecular Biology and DNA repair, Department of Medicine (DAME), University of Udine, Udine, Italy
| | - Giovanna Mangiapane
- Laboratory of Molecular Biology and DNA repair, Department of Medicine (DAME), University of Udine, Udine, Italy
| | - Emiliano Dalla
- Laboratory of Molecular Biology and DNA repair, Department of Medicine (DAME), University of Udine, Udine, Italy
| | - Gianluca Tell
- Laboratory of Molecular Biology and DNA repair, Department of Medicine (DAME), University of Udine, Udine, Italy
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29
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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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30
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Komakula SSB, Blaze B, Ye H, Dobrzyn A, Sampath H. A Novel Role for the DNA Repair Enzyme 8-Oxoguanine DNA Glycosylase in Adipogenesis. Int J Mol Sci 2021; 22:ijms22031152. [PMID: 33503804 PMCID: PMC7865743 DOI: 10.3390/ijms22031152] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/05/2021] [Accepted: 01/14/2021] [Indexed: 12/13/2022] Open
Abstract
Cells sustain constant oxidative stress from both exogenous and endogenous sources. When unmitigated by antioxidant defenses, reactive oxygen species damage cellular macromolecules, including DNA. Oxidative lesions in both nuclear and mitochondrial DNA are repaired via the base excision repair (BER) pathway, initiated by DNA glycosylases. We have previously demonstrated that the BER glycosylase 8-oxoguanine DNA glycosylase (OGG1) plays a novel role in body weight maintenance and regulation of adiposity. Specifically, mice lacking OGG1 (Ogg1−/−) are prone to increased fat accumulation with age and consumption of hypercaloric diets. Conversely, transgenic animals with mitochondrially-targeted overexpression of OGG1 (Ogg1Tg) are resistant to age- and diet-induced obesity. Given these phenotypes of altered adiposity in the context of OGG1 genotype, we sought to determine if OGG1 plays a cell-intrinsic role in adipocyte maturation and lipid accumulation. Here, we report that preadipocytes from Ogg1−/− mice differentiate more efficiently and accumulate more lipids than those from wild-type animals. Conversely, OGG1 overexpression significantly blunts adipogenic differentiation and lipid accretion in both pre-adipocytes from Ogg1Tg mice, as well as in 3T3-L1 cells with adenovirus-mediated OGG1 overexpression. Mechanistically, changes in adipogenesis are accompanied by significant alterations in cellular PARylation, corresponding with OGG1 genotype. Specifically, deletion of OGG1 reduces protein PARylation, concomitant with increased adipogenic differentiation, while OGG1 overexpression significantly increases PARylation and blunts adipogenesis. Collectively, these data indicate a novel role for OGG1 in modulating adipocyte differentiation and lipid accretion. These findings have important implications to our knowledge of the fundamental process of adipocyte differentiation, as well as to our understanding of lipid-related diseases such as obesity.
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Affiliation(s)
- Sai Santosh Babu Komakula
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901, USA; (S.S.B.K.); (B.B.); (H.Y.)
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland;
| | - Bhavya Blaze
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901, USA; (S.S.B.K.); (B.B.); (H.Y.)
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ 08901, USA
| | - Hong Ye
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901, USA; (S.S.B.K.); (B.B.); (H.Y.)
| | - Agnieszka Dobrzyn
- Laboratory of Cell Signaling and Metabolic Disorders, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland;
| | - Harini Sampath
- Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901, USA; (S.S.B.K.); (B.B.); (H.Y.)
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ 08901, USA
- Center for Microbiome, Nutrition, and Health, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ 08901, USA
- Correspondence:
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31
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Gorini F, Scala G, Cooke MS, Majello B, Amente S. Towards a comprehensive view of 8-oxo-7,8-dihydro-2'-deoxyguanosine: Highlighting the intertwined roles of DNA damage and epigenetics in genomic instability. DNA Repair (Amst) 2021; 97:103027. [PMID: 33285475 PMCID: PMC7926032 DOI: 10.1016/j.dnarep.2020.103027] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 11/16/2020] [Indexed: 12/12/2022]
Abstract
8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), a major product of DNA oxidation, is a pre-mutagenic lesion which is prone to mispair, if left unrepaired, with 2'-deoxyadenosine during DNA replication. While unrepaired or incompletely repaired 8-oxodG has classically been associated with genome instability and cancer, it has recently been reported to have a role in the epigenetic regulation of gene expression. Despite the growing collection of genome-wide 8-oxodG mapping studies that have been used to provide new insight on the functional nature of 8-oxodG within the genome, a comprehensive view that brings together the epigenetic and the mutagenic nature of the 8-oxodG is still lacking. To help address this gap, this review aims to provide (i) a description of the state-of-the-art knowledge on both the mutagenic and epigenetic roles of 8-oxodG; (ii) putative molecular models through which the 8-oxodG can cause genome instability; (iii) a possible molecular model on how 8-oxodG, acting as an epigenetic signal, could cause the translocations and deletions which are associated with cancer.
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Affiliation(s)
- Francesca Gorini
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples 'Federico II', Naples, Italy
| | - Giovanni Scala
- Department of Biology, University of Naples 'Federico II', Naples, Italy
| | - Marcus S Cooke
- Oxidative Stress Group, Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, FL, USA
| | - Barbara Majello
- Department of Biology, University of Naples 'Federico II', Naples, Italy
| | - Stefano Amente
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples 'Federico II', Naples, Italy.
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Arczewska KD, Krasuska W, Stachurska A, Karpińska K, Sikorska J, Kiedrowski M, Lange D, Stępień T, Czarnocka B. hMTH1 and GPX1 expression in human thyroid tissue is interrelated to prevent oxidative DNA damage. DNA Repair (Amst) 2020; 95:102954. [PMID: 32877752 DOI: 10.1016/j.dnarep.2020.102954] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 08/09/2020] [Accepted: 08/13/2020] [Indexed: 12/14/2022]
Abstract
Oxidative stress (OS) is recognized as disturbance of cellular equilibrium between reactive oxygen species (ROS) formation and their elimination by antioxidant defense systems. One example of ROS-mediated damage is generation of potentially mutagenic DNA precursor, 8-oxodGTP. In human cells genomic 8-oxodGTP incorporation is prevented by the MutT homologue 1 (MTH1 or hMTH1 for human MTH1) protein. It is well established that malignant cells, including thyroid cancer cells, require hMTH1 for maintaining proliferation and cancerous transformation phenotype. Above observations led to the development of hMTH1 inhibitors as novel anticancer therapeutics. In the current study we present extensive analysis of oxidative stress responses determining sensitivity to hMTH1 deficiency in cultured thyroid cells. We observe here that hMTH1 depletion results in downregulation of several glutathione-dependent OS defense system factors, including GPX1 and GCLM, making some of the tested thyroid cell lines highly dependent on glutathione levels. This is evidenced by the increased ROS burden and enhanced proliferation defect after combination of hMTH1 siRNA and glutathione synthesis inhibition. Moreover, due to the lack of data on hMTH1 expression in human thyroid tumor specimens we decided to perform detailed analysis of hMTH1 expression in thyroid tumor and peri-tumoral tissues from human patients. Our results allow us to propose here that anticancer activity of hMTH1 suppression may be boosted by combination with agents modulating glutathione pool, but further studies are necessary to precisely identify backgrounds susceptible to such combination treatment.
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Affiliation(s)
- Katarzyna D Arczewska
- Department of Biochemistry and Molecular Biology, Centre of Postgraduate Medical Education, Marymoncka 99/103, 01-813 Warsaw, Poland.
| | - Wanda Krasuska
- Department of Biochemistry and Molecular Biology, Centre of Postgraduate Medical Education, Marymoncka 99/103, 01-813 Warsaw, Poland
| | - Anna Stachurska
- Department of Immunohematology, Centre of Postgraduate Medical Education, Marymoncka 99/103, 01-813 Warsaw, Poland
| | - Kamila Karpińska
- Department of Biochemistry and Molecular Biology, Centre of Postgraduate Medical Education, Marymoncka 99/103, 01-813 Warsaw, Poland; Laboratory of the Molecular Biology of Cancer, Centre of New Technologies, University of Warsaw, S. Banacha 2c, 02-097 Warsaw, Poland
| | - Justyna Sikorska
- Department of Immunohematology, Centre of Postgraduate Medical Education, Marymoncka 99/103, 01-813 Warsaw, Poland
| | - Mirosław Kiedrowski
- Clinical Department of Oncology and Hematology, Central Clinical Hospital of the Ministry of Interior and Administration in Warsaw, Center of Postgraduate Medical Education, Wołowska 137, 02-507 Warsaw, Poland
| | - Dariusz Lange
- Tumor Pathology Department, Maria Skłodowska-Curie National Research Institute of Oncology, Gliwice Branch, Wybrzeże Armii Krajowej 15, 44-102 Gliwice, Poland
| | - Tomasz Stępień
- Department of General and Endocrinological Surgery, Copernicus Memorial Hospital, Pabianicka 62, 93-036 Łódź, Poland
| | - Barbara Czarnocka
- Department of Biochemistry and Molecular Biology, Centre of Postgraduate Medical Education, Marymoncka 99/103, 01-813 Warsaw, Poland
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Ligand-induced gene activation is associated with oxidative genome damage whose repair is required for transcription. Proc Natl Acad Sci U S A 2020; 117:22183-22192. [PMID: 32826329 PMCID: PMC7486736 DOI: 10.1073/pnas.1919445117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The endogenous genome damage induced by mitochondrial/cytosolic reactive oxygen species (ROS) is well recognized. However, similar damage induced by nuclear ROS generated via histone/cytosine-phosphate-guanine (CpG) demethylation during transcription has not been scrupulously investigated. This report documents the formation of genomic oxidized bases and single-strand breaks during ligand-induced gene activation via histone/CpG demethylation. That repair of these damages occurs preferentially in promoters and is essential for transcriptional activation underscore the essentiality of promoter-specific repair for transcription. In contrast, heat shock (HS) induction generates double-strand breaks, the repair of which is essential for the activation of HS-responsive genes. This study thus implies gross underestimation of endogenous oxidative genome damage and highlights the intrinsic diversity of damage and distinct repair processes associated with transcription. Among several reversible epigenetic changes occurring during transcriptional activation, only demethylation of histones and cytosine-phosphate-guanines (CpGs) in gene promoters and other regulatory regions by specific demethylase(s) generates reactive oxygen species (ROS), which oxidize DNA and other cellular components. Here, we show induction of oxidized bases and single-strand breaks (SSBs), but not direct double-strand breaks (DSBs), in the genome during gene activation by ligands of the nuclear receptor superfamily. We observed that these damages were preferentially repaired in promoters via the base excision repair (BER)/single-strand break repair (SSBR) pathway. Interestingly, BER/SSBR inhibition suppressed gene activation. Constitutive association of demethylases with BER/SSBR proteins in multiprotein complexes underscores the coordination of histone/DNA demethylation and genome repair during gene activation. However, ligand-independent transcriptional activation occurring during heat shock (HS) induction is associated with the generation of DSBs, the repair of which is likewise essential for the activation of HS-responsive genes. These observations suggest that the repair of distinct damages induced during diverse transcriptional activation is a universal prerequisite for transcription initiation. Because of limited investigation of demethylation-induced genome damage during transcription, this study suggests that the extent of oxidative genome damage resulting from various cellular processes is substantially underestimated.
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Varshney D, Spiegel J, Zyner K, Tannahill D, Balasubramanian S. The regulation and functions of DNA and RNA G-quadruplexes. Nat Rev Mol Cell Biol 2020; 21:459-474. [PMID: 32313204 PMCID: PMC7115845 DOI: 10.1038/s41580-020-0236-x] [Citation(s) in RCA: 600] [Impact Index Per Article: 150.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2020] [Indexed: 02/06/2023]
Abstract
DNA and RNA can adopt various secondary structures. Four-stranded G-quadruplex (G4) structures form through self-recognition of guanines into stacked tetrads, and considerable biophysical and structural evidence exists for G4 formation in vitro. Computational studies and sequencing methods have revealed the prevalence of G4 sequence motifs at gene regulatory regions in various genomes, including in humans. Experiments using chemical, molecular and cell biology methods have demonstrated that G4s exist in chromatin DNA and in RNA, and have linked G4 formation with key biological processes ranging from transcription and translation to genome instability and cancer. In this Review, we first discuss the identification of G4s and evidence for their formation in cells using chemical biology, imaging and genomic technologies. We then discuss possible functions of DNA G4s and their interacting proteins, particularly in transcription, telomere biology and genome instability. Roles of RNA G4s in RNA biology, especially in translation, are also discussed. Furthermore, we consider the emerging relationships of G4s with chromatin and with RNA modifications. Finally, we discuss the connection between G4 formation and synthetic lethality in cancer cells, and recent progress towards considering G4s as therapeutic targets in human diseases.
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Affiliation(s)
- Dhaval Varshney
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
| | - Jochen Spiegel
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
| | - Katherine Zyner
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
| | - David Tannahill
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK
| | - Shankar Balasubramanian
- Cancer Research UK Cambridge Institute, Li Ka Shing Centre, Cambridge, UK.
- Department of Chemistry, University of Cambridge, Cambridge, UK.
- School of Clinical Medicine, University of Cambridge, Cambridge, UK.
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35
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Gorini F, Scala G, Di Palo G, Dellino GI, Cocozza S, Pelicci PG, Lania L, Majello B, Amente S. The genomic landscape of 8-oxodG reveals enrichment at specific inherently fragile promoters. Nucleic Acids Res 2020; 48:4309-4324. [PMID: 32198884 PMCID: PMC7192600 DOI: 10.1093/nar/gkaa175] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/09/2020] [Accepted: 03/11/2020] [Indexed: 12/12/2022] Open
Abstract
8-Oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) is the most common marker of oxidative stress and its accumulation within the genome has been associated with major human health issues such as cancer, aging, cardiovascular and neurodegenerative diseases. The characterization of the different genomic sites where 8-oxodG accumulates and the mechanisms underlying its formation are still poorly understood. Using OxiDIP-seq, we recently derived the genome-wide distribution of 8-oxodG in human non-tumorigenic epithelial breast cells (MCF10A). Here, we identify a subset of human promoters that accumulate 8-oxodG under steady-state condition. 8-oxodG nucleotides co-localize with double strand breaks (DSBs) at bidirectional and CG skewed promoters and their density correlate with RNA Polymerase II co-occupancy and transcription. Furthermore, by performing OxiDIP-seq in quiescent (G0) cells, we found a strong reduction of oxidatively-generated damage in the majority of 8-oxodG-positive promoters in the absence of DNA replication. Overall, our results suggest that the accumulation of 8-oxodG at gene promoters occurs through DNA replication-dependent or -independent mechanisms, with a possible contribution to the formation of cancer-associated translocation events.
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Affiliation(s)
- Francesca Gorini
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples 'Federico II', Naples, Italy
| | - Giovanni Scala
- Department of Biology, University of Naples 'Federico II', Naples, Italy
| | - Giacomo Di Palo
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples 'Federico II', Naples, Italy
| | - Gaetano Ivan Dellino
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy.,Department of Oncology and Hemato-oncology, University of Milano, Milan, Italy
| | - Sergio Cocozza
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples 'Federico II', Naples, Italy
| | - Pier Giuseppe Pelicci
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy.,Department of Oncology and Hemato-oncology, University of Milano, Milan, Italy
| | - Luigi Lania
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples 'Federico II', Naples, Italy
| | - Barbara Majello
- Department of Biology, University of Naples 'Federico II', Naples, Italy
| | - Stefano Amente
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples 'Federico II', Naples, Italy
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36
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Rogers RA, Meyer MR, Stewart KM, Eyring GM, Fleming AM, Burrows CJ. Hysteresis in poly-2'-deoxycytidine i-motif folding is impacted by the method of analysis as well as loop and stem lengths. Biopolymers 2020; 112:e23389. [PMID: 33098582 DOI: 10.1002/bip.23389] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 06/06/2020] [Accepted: 06/11/2020] [Indexed: 02/06/2023]
Abstract
In DNA, i-motif (iM) folds occur under slightly acidic conditions when sequences rich in 2'-deoxycytidine (dC) nucleotides adopt consecutive dC self base pairs. The pH stability of an iM is defined by the midpoint in the pH transition (pHT ) between the folded and unfolded states. Two different experiments to determine pHT values via circular dichroism (CD) spectroscopy were performed on poly-dC iMs of length 15, 19, or 23 nucleotides. These experiments demonstrate two points: (1) pHT values were dependent on the titration experiment performed, and (2) pH-induced denaturing or annealing processes produced isothermal hysteresis in the pHT values. These results in tandem with model iMs with judicious mutations of dC to thymidine to favor particular folds found the hysteresis was maximal for the shorter poly-dC iMs and those with an even number of base pairs, while the hysteresis was minimal for longer poly-dC iMs and those with an odd number of base pairs. Experiments to follow the iM folding via thermal changes identified thermal hysteresis between the denaturing and annealing cycles. Similar trends were found to those observed in the CD experiments. The results demonstrate that the method of iM analysis can impact the pHT parameter measured, and hysteresis was observed in the pHT and Tm values.
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Affiliation(s)
- R Aaron Rogers
- Department of Chemistry, University of Utah, Salt Lake City, Utah, U.S.A
| | - Madeline R Meyer
- Department of Chemistry, University of Utah, Salt Lake City, Utah, U.S.A
| | - Kayla M Stewart
- Department of Chemistry, University of Utah, Salt Lake City, Utah, U.S.A
| | - Gabriela M Eyring
- Department of Chemistry, University of Utah, Salt Lake City, Utah, U.S.A
| | - Aaron M Fleming
- Department of Chemistry, University of Utah, Salt Lake City, Utah, U.S.A
| | - Cynthia J Burrows
- Department of Chemistry, University of Utah, Salt Lake City, Utah, U.S.A
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37
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Ferenc G, Váradi Z, Kupihár Z, Paragi G, Kovács L. Analytical and Structural Studies for the Investigation of Oxidative Stress in Guanine Oligonucleotides. Int J Mol Sci 2020; 21:E4981. [PMID: 32679695 PMCID: PMC7404036 DOI: 10.3390/ijms21144981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/08/2020] [Accepted: 07/13/2020] [Indexed: 11/16/2022] Open
Abstract
DNA damage plays a decisive role in epigenetic effects. The detection and analysis of DNA damages, like the most common change of guanine (G) to 8-oxo-7,8-dihydroguanine (OG), is a key factor in cancer research. It is especially true for G quadruplex structure (GQ), which is one of the best-known examples of a non-canonical DNA arrangement. In the present work, we provided an overview on analytical methods in connection with the detection of OG in oligonucleotides with GQ-forming capacity. Focusing on the last five years, novel electrochemical tools, like dedicated electrodes, were overviewed, as well as different optical methods (fluorometric assays, resonance light scattering or UV radiation) along with hyphenated detection and structural analysis methods (CD, NMR, melting temperature analysis and nanopore detection) were also applied for OG detection. Additionally, GQ-related computational simulations were also summarized. All these results emphasize that OG detection and the analysis of the effect of its presence in higher ordered structures like GQ is still a state-of-the-art research line with continuously increasing interest.
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Affiliation(s)
- Györgyi Ferenc
- Nucleic Acid Synthesis Laboratory, Biological Research Centre, Temesvári krt. 62, H-6726 Szeged, Hungary;
| | - Zoltán Váradi
- Nucleic Acids Laboratory, Department of Medicinal Chemistry, University of Szeged, Dóm tér 8, H-6720 Szeged, Hungary; (Z.V.); (Z.K.)
| | - Zoltán Kupihár
- Nucleic Acids Laboratory, Department of Medicinal Chemistry, University of Szeged, Dóm tér 8, H-6720 Szeged, Hungary; (Z.V.); (Z.K.)
| | - Gábor Paragi
- MTA-SZTE Biomimetic Systems Research Group, Dóm tér 8, 6720 Szeged, Hungary
- Institute of Physics, University of Pécs, Ifjúság útja 6, 7624 Pécs, Hungary
| | - Lajos Kovács
- Nucleic Acids Laboratory, Department of Medicinal Chemistry, University of Szeged, Dóm tér 8, H-6720 Szeged, Hungary; (Z.V.); (Z.K.)
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38
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Zafar M, Hazeslip L, Chauhan MZ, Byrd AK. The Expression of Human DNA Helicase B Is Affected by G-Quadruplexes in the Promoter. Biochemistry 2020; 59:2401-2409. [PMID: 32478505 PMCID: PMC7346868 DOI: 10.1021/acs.biochem.0c00218] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/26/2020] [Indexed: 12/25/2022]
Abstract
G-Quadruplexes are secondary structures that can form in guanine-rich DNA and RNA that have been implicated in regulating multiple biological processes, including transcription. G-Quadruplex-forming sequences are prevalent in promoter regions of proto-oncogenes and DNA repair proteins. HELB is a human helicase involved in DNA replication and repair with 12 runs of three to four guanines in the proximal promoter. This sequence has the potential to form three canonical three-tetrad G-quadruplexes. Our results show that although all three G-quadruplexes can form, a structure containing two noncanonical G-quadruplexes with longer loops containing runs of three to four guanines is the most prevalent. These HELB G-quadruplexes are stable under physiological conditions. In cells, stabilization of the G-quadruplexes results in a decrease in the level of HELB expression, suggesting that the G-quadruplexes in the HELB promoter serve as transcriptional repressors.
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Affiliation(s)
- Maroof
Khan Zafar
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, United States
| | - Lindsey Hazeslip
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, United States
| | - Muhammad Zain Chauhan
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, United States
| | - Alicia K. Byrd
- Department
of Biochemistry and Molecular Biology, University
of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, United States
- Winthrop
P. Rockefeller Cancer Institute, Little Rock, Arkansas 72205, United States
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39
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R-loop induced G-quadruplex in non-template promotes transcription by successive R-loop formation. Nat Commun 2020; 11:3392. [PMID: 32636376 PMCID: PMC7341879 DOI: 10.1038/s41467-020-17176-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 06/17/2020] [Indexed: 01/06/2023] Open
Abstract
G-quadruplex (G4) is a noncanonical secondary structure of DNA or RNA which can enhance or repress gene expression, yet the underlying molecular mechanism remains uncertain. Here we show that when positioned downstream of transcription start site, the orientation of potential G4 forming sequence (PQS), but not the sequence alters transcriptional output. Ensemble in vitro transcription assays indicate that PQS in the non-template increases mRNA production rate and yield. Using sequential single molecule detection stages, we demonstrate that while binding and initiation of T7 RNA polymerase is unchanged, the efficiency of elongation and the final mRNA output is higher when PQS is in the non-template. Strikingly, the enhanced elongation arises from the transcription-induced R-loop formation, which in turn generates G4 structure in the non-template. The G4 stabilized R-loop leads to increased transcription by a mechanism involving successive rounds of R-loop formation. G-quadruplex (G4) forming sequences are highly enriched in the human genome and function as important regulators of diverse range of biological processes. Here the authors show that while G4 structures on template strand block transcription, folding on the non-template strand enhances transcription by means of successive R-loop formation.
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40
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Fleming AM, Zhu J, Jara-Espejo M, Burrows CJ. Cruciform DNA Sequences in Gene Promoters Can Impact Transcription upon Oxidative Modification of 2'-Deoxyguanosine. Biochemistry 2020; 59:2616-2626. [PMID: 32567845 DOI: 10.1021/acs.biochem.0c00387] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sequences of DNA typically adopt B-form duplexes in genomes, although noncanonical structures such as G-quadruplexes, i-motifs, Z-DNA, and cruciform structures can occur. A challenge is to determine the functions of these various structures in cellular processes. We and others have hypothesized that G-rich G-quadruplex-forming sequences in human genome promoters serve to sense oxidative damage generated during oxidative stress impacting gene regulation. Herein, chemical tools and a cell-based assay were used to study the oxidation of guanine to 8-oxo-7,8-dihydroguanine (OG) in the context of a cruciform-forming sequence in a gene promoter to determine the impact on transcription. We found that OG in the nontemplate strand in the loop of a cruciform-forming sequence could induce gene expression; conversely when OG was in the same sequence on the template strand, gene expression was inhibited. A model for the transcriptional changes observed is proposed in which OG focuses the DNA repair process on the promoter to impact expression. Our cellular and biophysical studies and literature sources support the idea that removal of OG from duplex DNA by OGG1 yields an abasic site (AP) that triggers a structural shift to the cruciform fold. The AP-bearing cruciform structure is presented to APE1, which functions as a conduit between DNA repair and gene regulation. The significance is enhanced by a bioinformatic study of all human gene promoters and transcription termination sites for inverted repeats (IRs). Comparison of the two regions showed that promoters have stable and G-rich IRs at a low frequency and termination sites have many AT-rich IRs with low stability.
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Affiliation(s)
- Aaron M Fleming
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States
| | - Judy Zhu
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States
| | - Manuel Jara-Espejo
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States.,Department of Morphology, Piracicaba Dental School, University of Campinas-UNICAMP, Av. Limeira 901, Piracicaba, CEP 13414-018 Sao Paulo, Brazil
| | - Cynthia J Burrows
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States
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41
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Debnath S, Sharma S. RECQ1 Helicase in Genomic Stability and Cancer. Genes (Basel) 2020; 11:E622. [PMID: 32517021 PMCID: PMC7348745 DOI: 10.3390/genes11060622] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/01/2020] [Accepted: 06/03/2020] [Indexed: 12/13/2022] Open
Abstract
RECQ1 (also known as RECQL or RECQL1) belongs to the RecQ family of DNA helicases, members of which are linked with rare genetic diseases of cancer predisposition in humans. RECQ1 is implicated in several cellular processes, including DNA repair, cell cycle and growth, telomere maintenance, and transcription. Earlier studies have demonstrated a unique requirement of RECQ1 in ensuring chromosomal stability and suggested its potential involvement in tumorigenesis. Recent reports have suggested that RECQ1 is a potential breast cancer susceptibility gene, and missense mutations in this gene contribute to familial breast cancer development. Here, we provide a framework for understanding how the genetic or functional loss of RECQ1 might contribute to genomic instability and cancer.
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Affiliation(s)
- Subrata Debnath
- Department of Biochemistry and Molecular Biology, College of Medicine, Howard University, 520 W Street, NW, Washington, DC 20059, USA;
| | - Sudha Sharma
- Department of Biochemistry and Molecular Biology, College of Medicine, Howard University, 520 W Street, NW, Washington, DC 20059, USA;
- National Human Genome Center, College of Medicine, Howard University, 520 W Street, NW, Washington, DC 20059, USA
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42
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Herbert A. ALU non-B-DNA conformations, flipons, binary codes and evolution. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200222. [PMID: 32742689 PMCID: PMC7353975 DOI: 10.1098/rsos.200222] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 05/18/2020] [Indexed: 05/08/2023]
Abstract
ALUs contribute to genetic diversity by altering DNA's linear sequence through retrotransposition, recombination and repair. ALUs also have the potential to form alternative non-B-DNA conformations such as Z-DNA, triplexes and quadruplexes that alter the read-out of information from the genome. I suggest here these structures enable the rapid reprogramming of cellular pathways to offset DNA damage and regulate inflammation. The experimental data supporting this form of genetic encoding is presented. ALU sequence motifs that form non-B-DNA conformations under physiological conditions are called flipons. Flipons are binary switches. They are dissipative structures that trade energy for information. By efficiently targeting cellular machines to active genes, flipons expand the repertoire of RNAs compiled from a gene. Their action greatly increases the informational capacity of linearly encoded genomes. Flipons are programmable by epigenetic modification, synchronizing cellular events by altering both chromatin state and nucleosome phasing. Different classes of flipon exist. Z-flipons are based on Z-DNA and modify the transcripts compiled from a gene. T-flipons are based on triplexes and localize non-coding RNAs that direct the assembly of cellular machines. G-flipons are based on G-quadruplexes and sense DNA damage, then trigger the appropriate protective responses. Flipon conformation is dynamic, changing with context. When frozen in one state, flipons often cause disease. The propagation of flipons throughout the genome by ALU elements represents a novel evolutionary innovation that allows for rapid change. Each ALU insertion creates variability by extracting a different set of information from the neighbourhood in which it lands. By elaborating on already successful adaptations, the newly compiled transcripts work with the old to enhance survival. Systems that optimize flipon settings through learning can adapt faster than with other forms of evolution. They avoid the risk of relying on random and irreversible codon rewrites.
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43
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Hao W, Wang J, Zhang Y, Wang C, Xia L, Zhang W, Zafar M, Kang JY, Wang R, Ali Bohio A, Pan L, Zeng X, Wei M, Boldogh I, Ba X. Enzymatically inactive OGG1 binds to DNA and steers base excision repair toward gene transcription. FASEB J 2020; 34:7427-7441. [PMID: 32378256 PMCID: PMC7318607 DOI: 10.1096/fj.201902243r] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 11/19/2019] [Accepted: 03/17/2020] [Indexed: 12/11/2022]
Abstract
8‐Oxoguanine DNA glycosylase1 (OGG1)‐initiated base excision repair (BER) is the primary pathway to remove the pre‐mutagenic 8‐oxo‐7,8‐dihydroguanine (8‐oxoG) from DNA. Recent studies documented 8‐oxoG serves as an epigenetic‐like mark and OGG1 modulates gene expression in oxidatively stressed cells. For this new role of OGG1, two distinct mechanisms have been proposed: one is coupled to base excision, while the other only requires substrate binding of OGG1––both resulting in conformational adjustment in the adjacent DNA sequences providing access for transcription factors to their cis‐elements. The present study aimed to examine if BER activity of OGG1 is required for pro‐inflammatory gene expression. To this end, Ogg1/OGG1 knockout/depleted cells were transfected with constructs expressing wild‐type (wt) and repair‐deficient mutants of OGG1. OGG1's promoter enrichment, oxidative state, and gene expression were examined. Results showed that TNFα exposure increased levels of oxidatively modified cysteine(s) of wt OGG1 without impairing its association with promoter and facilitated gene expression. The excision deficient K249Q mutant was even a more potent activator of gene expression; whereas, mutant OGG1 with impaired substrate recognition/binding was not. These data suggested the interaction of OGG1 with its substrate at regulatory regions followed by conformational adjustment in the adjacent DNA is the primary mode to modulate inflammatory gene expression.
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Affiliation(s)
- Wenjing Hao
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China.,School of Life Science, Northeast Normal University, Changchun, China
| | - Jing Wang
- Department of Respiratory Medicine, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Yuanhang Zhang
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China.,School of Life Science, Northeast Normal University, Changchun, China
| | - Chenxin Wang
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China.,School of Life Science, Northeast Normal University, Changchun, China
| | - Lan Xia
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China.,School of Life Science, Northeast Normal University, Changchun, China
| | - Wenhe Zhang
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China.,School of Life Science, Northeast Normal University, Changchun, China
| | - Muhammad Zafar
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China.,School of Life Science, Northeast Normal University, Changchun, China
| | - Ju-Yong Kang
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China.,Faculty of Life Science, Kim Il Sung University, Pyongyang, DPRK
| | - Ruoxi Wang
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China.,School of Life Science, Northeast Normal University, Changchun, China.,Key Laboratory of Animal Resistance Biology of Shandong Province, Institute of Biomedical Sciences, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Ameer Ali Bohio
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China.,School of Life Science, Northeast Normal University, Changchun, China
| | - Lang Pan
- School of Life Science, Northeast Normal University, Changchun, China.,Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX, USA
| | - Xianlu Zeng
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China.,School of Life Science, Northeast Normal University, Changchun, China
| | - Min Wei
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China.,School of Life Science, Northeast Normal University, Changchun, China
| | - Istvan Boldogh
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX, USA
| | - Xueqing Ba
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Northeast Normal University, Changchun, China.,School of Life Science, Northeast Normal University, Changchun, China
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44
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Salsbury AM, Dean TJ, Lemkul JA. Polarizable Molecular Dynamics Simulations of Two c-kit Oncogene Promoter G-Quadruplexes: Effect of Primary and Secondary Structure on Loop and Ion Sampling. J Chem Theory Comput 2020; 16:3430-3444. [PMID: 32307997 DOI: 10.1021/acs.jctc.0c00191] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
G-quadruplexes (GQs) are highly ordered nucleic acid structures that play fundamental roles in regulating gene expression and maintaining genomic stability. GQs are topologically diverse and enriched in promoter sequences of growth regulatory genes and proto-oncogenes, suggesting that they may serve as attractive targets for drug design at the level of transcription rather than inhibiting the activity of the protein products of these genes. The c-kit promoter contains three adjacent GQ-forming sequences that have proposed antagonistic effects on gene expression and thus are promising drug targets for diseases such as gastrointestinal stromal tumors, mast cell disease, and leukemia. Because GQ stability is influenced by primary structure, secondary structure, and ion interactions, a greater understanding of GQ structure, dynamics, and ion binding properties is needed to develop novel, GQ-targeting therapeutics. Here, we performed molecular dynamics simulations to systematically study the c-kit2 and c-kit* GQs, evaluating nonpolarizable and polarizable force fields (FFs) and examining the effects of base substitutions and cation type (K+, Na+, and Li+) on the dynamics of their isolated and linked structures. We found that the Drude polarizable FF outperformed the additive CHARMM36 FF in two- and three-tetrad GQs and solutions of KCl, NaCl, and LiCl. Drude simulations with different cations agreed with the known GQ stabilization preference (K+ > Na+ > Li+) and illustrated that tetrad core-ion coordination differs as a function of cation type. Finally, we showed that differences in primary and secondary structure influence loop sampling, ion binding, and core-ion energetics of GQs.
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Affiliation(s)
- Alexa M Salsbury
- Department of Biochemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Tanner J Dean
- Department of Biochemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Justin A Lemkul
- Department of Biochemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia 24061, United States
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45
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Fleming AM, Burrows CJ. Interplay of Guanine Oxidation and G-Quadruplex Folding in Gene Promoters. J Am Chem Soc 2020; 142:1115-1136. [PMID: 31880930 PMCID: PMC6988379 DOI: 10.1021/jacs.9b11050] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Living in an oxygen atmosphere demands an ability to thrive in the presence of reactive oxygen species (ROS). Aerobic organisms have successfully found solutions to the oxidative threats imposed by ROS by evolving an elaborate detoxification system, upregulating ROS during inflammation, and utilizing ROS as messenger molecules. In this Perspective, recent studies are discussed that demonstrate ROS as signaling molecules for gene regulation by combining two emergent properties of the guanine (G) heterocycle in DNA, namely, oxidation sensitivity and a propensity for G-quadruplex (G4) folding, both of which depend upon sequence context. In human gene promoters, this results from an elevated 5'-GG-3' dinucleotide frequency and GC enrichment near transcription start sites. Oxidation of DNA by ROS drives conversion of G to 8-oxo-7,8-dihydroguanine (OG) to mark target promoters for base excision repair initiated by OG-glycosylase I (OGG1). Sequence-dependent mechanisms for gene activation are available to OGG1 to induce transcription. Either OGG1 releases OG to yield an abasic site driving formation of a non-canonical fold, such as a G4, to be displayed to apurinic/apyrimidinic 1 (APE1) and stalling on the fold to recruit activating factors, or OGG1 binds OG and facilitates activator protein recruitment. The mechanisms described drive induction of stress response, DNA repair, or estrogen-induced genes, and these pathways are novel potential anticancer targets for therapeutic intervention. Chemical concepts provide a framework to discuss the regulatory or possible epigenetic potential of the OG modification in DNA, in which DNA "damage" and non-canonical folds collaborate to turn on or off gene expression. The next steps for scientific discovery in this growing field are discussed.
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Affiliation(s)
- Aaron M. Fleming
- 315 South 1400 East, Dept. of Chemistry, University of Utah, Salt Lake City, UT 84112-0850, USA
| | - Cynthia J. Burrows
- 315 South 1400 East, Dept. of Chemistry, University of Utah, Salt Lake City, UT 84112-0850, USA
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46
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Poetsch AR. The genomics of oxidative DNA damage, repair, and resulting mutagenesis. Comput Struct Biotechnol J 2020; 18:207-219. [PMID: 31993111 PMCID: PMC6974700 DOI: 10.1016/j.csbj.2019.12.013] [Citation(s) in RCA: 170] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 12/13/2019] [Accepted: 12/21/2019] [Indexed: 12/22/2022] Open
Abstract
Reactive oxygen species are a constant threat to DNA as they modify bases with the risk of disrupting genome function, inducing genome instability and mutation. Such risks are due to primary oxidative DNA damage and also mediated by the repair process. This leads to a delicate decision process for the cell as to whether to repair a damaged base at a specific genomic location or better leave it unrepaired. Persistent DNA damage can disrupt genome function, but on the other hand it can also contribute to gene regulation by serving as an epigenetic mark. When such processes are out of balance, pathophysiological conditions could get accelerated, because oxidative DNA damage and resulting mutagenic processes are tightly linked to ageing, inflammation, and the development of multiple age-related diseases, such as cancer and neurodegenerative disorders. Recent technological advancements and novel data analysis strategies have revealed that oxidative DNA damage, its repair, and related mutations distribute heterogeneously over the genome at multiple levels of resolution. The involved mechanisms act in the context of genome sequence, in interaction with genome function and chromatin. This review addresses what we currently know about the genome distribution of oxidative DNA damage, repair intermediates, and mutations. It will specifically focus on the various methodologies to measure oxidative DNA damage distribution and discuss the mechanistic conclusions derived from the different approaches. It will also address the consequences of oxidative DNA damage, specifically how it gives rise to mutations, genome instability, and how it can act as an epigenetic mark.
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47
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Zhang M, Wang B, Li T, Liu R, Xiao Y, Geng X, Li G, Liu Q, Price CM, Liu Y, Wang F. Mammalian CST averts replication failure by preventing G-quadruplex accumulation. Nucleic Acids Res 2019; 47:5243-5259. [PMID: 30976812 PMCID: PMC6547417 DOI: 10.1093/nar/gkz264] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 03/28/2019] [Accepted: 04/03/2019] [Indexed: 11/12/2022] Open
Abstract
Human CST (CTC1-STN1-TEN1) is an RPA-like complex that associates with G-rich single-strand DNA and helps resolve replication problems both at telomeres and genome-wide. We previously showed that CST binds and disrupts G-quadruplex (G4) DNA in vitro, suggesting that CST may prevent in vivo blocks to replication by resolving G4 structures. Here, we demonstrate that CST binds and unfolds G4 with similar efficiency to RPA. In cells, CST is recruited to telomeric and non-telomeric chromatin upon G4 stabilization, even when ATR/ATM pathways were inhibited. STN1 depletion increases G4 accumulation and slows bulk genomic DNA replication. At telomeres, combined STN1 depletion and G4 stabilization causes multi-telomere FISH signals and telomere loss, hallmarks of deficient telomere duplex replication. Strand-specific telomere FISH indicates preferential loss of C-strand DNA while analysis of BrdU uptake during leading and lagging-strand telomere replication shows preferential under-replication of lagging telomeres. Together these results indicate a block to Okazaki fragment synthesis. Overall, our findings indicate a novel role for CST in maintaining genome integrity through resolution of G4 structures both ahead of the replication fork and on the lagging strand template.
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Affiliation(s)
- Miaomiao Zhang
- Department of Genetics, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, PR China
| | - Bing Wang
- Department of Genetics, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, PR China
| | - Tingfang Li
- Department of Genetics, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, PR China
| | - Rui Liu
- Department of Genetics, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, PR China
| | - Yingnan Xiao
- Department of Genetics, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, PR China
| | - Xin Geng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, PR China
| | - Guang Li
- Department of Genetics, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, PR China
| | - Qiang Liu
- Department of Radiobiology, Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College,Tianjin 300192, PR China
| | - Carolyn M Price
- Departments of Cancer and Cell Biology, University of Cincinnati, Cincinnati, OH, USA
| | - Yang Liu
- Department of Radiobiology, Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College,Tianjin 300192, PR China
| | - Feng Wang
- Department of Genetics, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, PR China
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48
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Fleming AM, Zhu J, Ding Y, Burrows CJ. Location dependence of the transcriptional response of a potential G-quadruplex in gene promoters under oxidative stress. Nucleic Acids Res 2019; 47:5049-5060. [PMID: 30916339 PMCID: PMC6547423 DOI: 10.1093/nar/gkz207] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 02/09/2019] [Accepted: 03/18/2019] [Indexed: 12/25/2022] Open
Abstract
Oxidation of the guanine (G) heterocycle to 8-oxo-7,8-dihydroguanine (OG) in mammalian gene promoters was demonstrated to induce transcription. Potential G-quadruplex forming sequences (PQSs) in promoters have a high density of G nucleotides rendering them highly susceptible to oxidation and possible gene activation. The VEGF PQS with OG or an abasic site were synthesized at key locations in the SV40 or HSV-TK model promoters to determine the location dependency in the gene expression profile in human cells. The PQS location with respect to the transcription start site (TSS) and strand of occupancy (coding versus non-coding strand) are key parameters that determine the magnitude and direction in which gene expression changes with the chemically modified VEGF PQS. The greatest impact observed for OG or F in the PQS context in these promoters was within ∼200 bp of the TSS. Established PQSs found to occur naturally in a similar location relative to the TSS for possible oxidation-induced gene activation include c-MYC, KRAS, c-KIT, HIF-1α, PDGF-A and hTERT. The studies provide experimental constraints that were used to probe bioinformatic data regarding PQSs in the human genome for those that have the possibility to be redox switches for gene regulation.
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Affiliation(s)
- Aaron M Fleming
- 315 South 1400 East, Dept. of Chemistry, University of Utah, Salt Lake City, UT 84112-0850, USA
| | - Judy Zhu
- 315 South 1400 East, Dept. of Chemistry, University of Utah, Salt Lake City, UT 84112-0850, USA
| | - Yun Ding
- 315 South 1400 East, Dept. of Chemistry, University of Utah, Salt Lake City, UT 84112-0850, USA
| | - Cynthia J Burrows
- 315 South 1400 East, Dept. of Chemistry, University of Utah, Salt Lake City, UT 84112-0850, USA
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8-OxoG in GC-rich Sp1 binding sites enhances gene transcription in adipose tissue of juvenile mice. Sci Rep 2019; 9:15618. [PMID: 31666587 PMCID: PMC6821754 DOI: 10.1038/s41598-019-52139-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 10/12/2019] [Indexed: 12/27/2022] Open
Abstract
The oxidation of guanine to 8-oxoguanine (8-oxoG) is the most common type of oxidative DNA lesion. There is a growing body of evidence indicating that 8-oxoG is not only pre-mutagenic, but also plays an essential role in modulating gene expression along with its cognate repair proteins. In this study, we investigated the relationship between 8-oxoG formed under intrinsic oxidative stress conditions and gene expression in adipose and lung tissues of juvenile mice. We observed that transcriptional activity and the number of active genes were significantly correlated with the distribution of 8-oxoG in gene promoter regions, as determined by reverse-phase liquid chromatography/mass spectrometry (RP-LC/MS), and 8-oxoG and RNA sequencing. Gene regulation by 8-oxoG was not associated with the degree of 8-oxoG formation. Instead, genes with GC-rich transcription factor binding sites in their promoters became more active with increasing 8-oxoG abundance as also demonstrated by specificity protein 1 (Sp1)- and estrogen response element (ERE)-luciferase assays in human embryonic kidney (HEK293T) cells. These results indicate that the occurrence of 8-oxoG in GC-rich Sp1 binding sites is important for gene regulation during adipose tissue development.
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50
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Petri net-based model of the human DNA base excision repair pathway. PLoS One 2019; 14:e0217913. [PMID: 31518347 PMCID: PMC6743755 DOI: 10.1371/journal.pone.0217913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 05/21/2019] [Indexed: 12/14/2022] Open
Abstract
Cellular DNA is daily exposed to several damaging agents causing a plethora of DNA lesions. As a first aid to restore DNA integrity, several enzymes got specialized in damage recognition and lesion removal during the process called base excision repair (BER). A large number of DNA damage types and several different readers of nucleic acids lesions during BER pathway as well as two sub-pathways were considered in the definition of a model using the Petri net framework. The intuitive graphical representation in combination with precise mathematical analysis methods are the strong advantages of the Petri net-based representation of biological processes and make Petri nets a promising approach for modeling and analysis of human BER. The reported results provide new information that will aid efforts to characterize in silico knockouts as well as help to predict the sensitivity of the cell with inactivated repair proteins to different types of DNA damage. The results can also help in identifying the by-passing pathways that may lead to lack of pronounced phenotypes associated with mutations in some of the proteins. This knowledge is very useful when DNA damage-inducing drugs are introduced for cancer therapy, and lack of DNA repair is desirable for tumor cell death.
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