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DNA glycosylases

Jie Meng, Wenxiong Wang, Li Li, Qi Yin, Guofan Zhang
Marine molluscs, including oysters, can concentrate high levels of cadmium (Cd) in their soft tissues, but the molecular mechanisms of Cd toxicity remain speculative. In this study, Pacific oysters (Crassostrea gigas) were exposed to Cd for 9 days and their gills were subjected to proteomic analysis, which were further confirmed with transcriptomic analysis. A total of 4,964 proteins was quantified and 515 differentially expressed proteins were identified in response to Cd exposure. Gene Ontology enrichment analysis revealed that excess Cd affected the DNA and protein metabolism...
September 15, 2017: Scientific Reports
Ki Cheon Kim, Madduma Hewage Susara Ruwan Kumara, Kyoung Ah Kang, Mei Jing Piao, Min Chang Oh, Yea Seong Ryu, Jin Oh Jo, Young Sun Mok, Jennifer H Shin, Yeunsoo Park, Seong Bong Kim, Suk Jae Yoo, Jin Won Hyun
Oxidative stress enhances cellular DNA oxidation and may cause mutations in DNA bases, including 8‑oxoguanine (8‑oxoG). Our recent study reported that exposure of cells to non‑thermal dielectric barrier discharge (DBD) plasma generates reactive oxygen species and damages DNA. The present study investigated the effect of non‑thermal DBD plasma exposure on the formation of 8‑oxoG in HaCaT human keratinocytes. Cells exposed to DBD plasma exhibited increased level of 8‑oxoG. In addition, mRNA and protein expression levels of 8‑oxoguanine glycosylase 1 (OGG1), an 8‑oxoG repair enzyme, were reduced in plasma‑exposed cells...
September 11, 2017: Molecular Medicine Reports
E Horvathova, K Kozics, M Melusova, E Galova, A Sevcovicova, B Kusznierewicz, T Chmiel, D Slamenova
Knowledge of biological properties of natural compounds allows to understand their therapeutic value, efficacy and security. We investigated: composition of Lavandula angustifolia (LA) and Rosmarinus officinalis (RO) extracts, their antioxidant capacity, cytotoxicity and genotoxicity, their DNA-protective potential against DNA damage induced in hamster V79 cells by several genotoxins or in plasmid DNA by Fe2+ ions and activity of antioxidant enzymes in cells treated with these extracts. Higher cytotoxicity, observed at higher concentrations of extracts, was accompanied by the increased level of single-strand (ss) DNA breaks as well as formamidopyrimidine DNA glycosylase (Fpg) sensitive sites...
September 12, 2017: Neoplasma
Tina Pawar, Magnar Bjørås, Arne Klungland, Lars Eide
The mitochondrial DNA (mtDNA) resides in the vicinity of energy-rich reactions. Thus, chemical modifications of mtDNA might mirror mitochondrial processes and could serve as biomarkers of metabolic processes in the mitochondria. This hypothesis was tested by assessing modifications at 17 different sites in the mtDNA as a function of cell type, oxidative stress and mitochondrial activity. Two mouse mutants with a metabolic phenotype were compared to wild-type (WT) mice: the ogg1(-/-) mouse that lacks the 8-oxoguanine DNA glycosylase (OGG1), and the alkbh7(-/-) mouse missing the ALKBH7 protein that has been implicated in fatty acid oxidation...
September 8, 2017: Mitochondrion
Katharina Bilotti, Erin E Kennedy, Chuxuan Li, Sarah Delaney
If unrepaired, damage to genomic DNA can cause mutations and/or be cytotoxic. Single base lesions are repaired via the base excision repair (BER) pathway. The first step in BER is the recognition and removal of the nucleobase lesion by a glycosylase enzyme. For example, human oxoguanine glycosylase 1 (hOGG1) is responsible for removal of the prototypic oxidatively damaged nucleobase, 8-oxo-7,8-dihydroguanine (8-oxoG). To date, most studies of glycosylases have used free duplex DNA substrates. However, cellular DNA is packaged as repeating nucleosome units, with 145 base pair segments of DNA wrapped around histone protein octamers...
September 1, 2017: DNA Repair
Carrie M Margulies, Isaac Alexander Chaim, Aprotim Mazumder, June Criscione, Leona D Samson
Alkylating agents are ubiquitous in our internal and external environments, causing DNA damage that contributes to mutations and cell death that can result in aging, tissue degeneration and cancer. Repair of methylated DNA bases occurs primarily through the base excision repair (BER) pathway, a multi-enzyme pathway initiated by the alkyladenine DNA glycosylase (Aag, also known as Mpg). Previous work demonstrated that mice treated with the alkylating agent methyl methanesulfonate (MMS) undergo cerebellar degeneration in an Aag-dependent manner, whereby increased BER initiation by Aag causes increased tissue damage that is dependent on activation of poly (ADP-ribose) polymerase 1 (Parp1)...
2017: PloS One
Jing Wang, Todd Blevins, Ram Podicheti, Jeremy R Haag, Ek Han Tan, Feng Wang, Craig S Pikaard
In eukaryotes, transcriptionally inactive loci are enriched within highly condensed heterochromatin. In plants, as in mammals, the DNA of heterochromatin is densely methylated and wrapped by histones displaying a characteristic subset of post-translational modifications. Growing evidence indicates that these chromatin modifications are not sufficient for silencing. Instead, they are prerequisites for further assembly of higher-order chromatin structures that are refractory to transcription but not fully understood...
September 7, 2017: Genes & Development
Jorge E Vela-Guajardo, Perla Pérez-Treviño, Irais Rivera-Álvarez, Fabio A González-Mondellini, Julio Altamirano, Noemí García
Cardiac hypertrophy is a compensatory mechanism maladapted because it presents an increase in the oxidative stress which could be associated with the development of the heart failure. A mechanism proposed is by mitochondrial DNA (mtDNA) oxidation, which evolved to a vicious cycle because of the synthesis of proteins encoded in the genome is committed. Therefore, the aim of the present work was to evaluate the mtDNA damage and enzyme repairing the 8-oxo-deoxyguanosine glycosylase mitochondrial isoform 1-2a (OGG1-2a) in the early stage of compensated cardiac hypertrophy induced by abdominal aortic constriction (AAC)...
August 24, 2017: Journal of the American Society of Hypertension: JASH
Edith Buchinger, Siv Å Wiik, Anna Kusnierczyk, Renana Rabe, Per A Aas, Bodil Kavli, Geir Slupphaug, Finn L Aachmann
Human uracil N-glycosylase isoform 2-UNG2 consists of an N-terminal intrinsically disordered regulatory domain (UNG2 residues 1-92, 9.3 kDa) and a C-terminal structured catalytic domain (UNG2 residues 93-313, 25.1 kDa). Here, we report the backbone (1)H, (13)C, and (15)N chemical shift assignment as well as secondary structure analysis of the N-and C-terminal domains of UNG2 representing the full-length UNG2 protein.
September 6, 2017: Biomolecular NMR Assignments
Sergi Puig, Lucía Ramos-Alonso, Antonia María Romero, María Teresa Martínez-Pastor
Iron is an essential redox element that functions as a cofactor in many metabolic pathways. Critical enzymes in DNA metabolism, including multiple DNA repair enzymes (helicases, nucleases, glycosylases, demethylases) and ribonucleotide reductase, use iron as an indispensable cofactor to function. Recent striking results have revealed that the catalytic subunit of DNA polymerases also contains conserved cysteine-rich motifs that bind iron-sulfur (Fe/S) clusters that are essential for the formation of stable and active complexes...
September 7, 2017: Metallomics: Integrated Biometal Science
Alexis C Komor, Kevin T Zhao, Michael S Packer, Nicole M Gaudelli, Amanda L Waterbury, Luke W Koblan, Y Bill Kim, Ahmed H Badran, David R Liu
We recently developed base editing, the programmable conversion of target C:G base pairs to T:A without inducing double-stranded DNA breaks (DSBs) or requiring homology-directed repair using engineered fusions of Cas9 variants and cytidine deaminases. Over the past year, the third-generation base editor (BE3) and related technologies have been successfully used by many researchers in a wide range of organisms. The product distribution of base editing-the frequency with which the target C:G is converted to mixtures of undesired by-products, along with the desired T:A product-varies in a target site-dependent manner...
August 2017: Science Advances
Amaia Iriondo-DeHond, Ana I Haza, Alicia Ávalos, María Dolores Del Castillo, Paloma Morales
The aim of the present study was to validate the food safety of CSE, by studying its effect on cytotoxicity (100-20000μg/ml) and genotoxicity (10, 100 and 1000μg/ml) and also to investigate its preventive potential (1, 10 and 100μg/ml) against B(a)P induced DNA damage. Prior to analyses, the antioxidant capacity and the microbiological quality of CSE were tested. DNA damage (strand breaks and oxidized purines/pyrimidines) was evaluated by the alkaline single-cell gel electrophoresis or comet assay. HepG2 cells were pre-treated with CSE (1, 10 and 100μg/ml) for 24h followed by the addition of 100μM B(a)P in presence of CSE for other 24h...
October 2017: Food Research International
Jia Zhou, Jany Chan, Marie Lambelé, Timur Yusufzai, Jason Stumpff, Patricia L Opresko, Markus Thali, Susan S Wallace
Oxidative damage to telomere DNA compromises telomere integrity. We recently reported that the DNA glycosylase NEIL3 preferentially repairs oxidative lesions in telomere sequences in vitro. Here, we show that loss of NEIL3 causes anaphase DNA bridging because of telomere dysfunction. NEIL3 expression increases during S phase and reaches maximal levels in late S/G2. NEIL3 co-localizes with TRF2 and associates with telomeres during S phase, and this association increases upon oxidative stress. Mechanistic studies reveal that NEIL3 binds to single-stranded DNA via its intrinsically disordered C terminus in a telomere-sequence-independent manner...
August 29, 2017: Cell Reports
Szu-Ping Huang, Tzu-Ming Ho, Chih-Wen Yang, Ya-Ju Chang, Jie-Fu Chen, Ning-Sing Shaw, Jia-Cherng Horng, Shih-Lan Hsu, Ming-Yuan Liao, Li-Chen Wu, Ja-An Annie Ho
Luobuma (Apocynum venetum L. (AVL)) is a popular beverage in Asia and has been reportedly to be associated with the bioactivities such as cardiotonic, diuretic, antioxidative, and antihypertensive. However, its biofunction as chemoprevention activity is seldom addressed. Herein, we aimed to characterize the anti-androgen-insensitive-prostate-cancer (anti-AIPC) bioactive compounds of Luobuma, and to investigate the associated molecular mechanisms. Activity-guided-fractionation (antioxidative activity and cell survivability) of Luobuma ethanolic extracts was performed to isolate and characterize the major bioactive compounds using Ultra Performance Liquid Chromatography (UPLC), Liquid Chromatography-Mass Spectrometry (LC-MS), and Nuclear Magnetic Resonance (NMR)...
August 28, 2017: Nutrients
Marco Seifermann, Alexander Ulges, Tobias Bopp, Svetlana Melcea, Andrea Schäfer, Sugako Oka, Yusaku Nakabeppu, Arne Klungland, Christof Niehrs, Bernd Epe
OGG1 (8-oxoguanine-DNA glycosylase) is the major DNA repair glycosylase removing the premutagenic DNA base modification 8-oxo-7,8-dihydroguanine (8-oxoG) from the genome of mammalian cells. In addition, there is accumulating evidence that OGG1 and its substrate 8-oxoG might function in the regulation of certain genes, which could account for an attenuated immune response observed in Ogg1(-/-) mice in several settings. Indications for at least two different mechanisms have been obtained. Thus, OGG1 could either act as an ancillary transcription factor cooperating with the lysine-specific demethylase LSD1 or as an activator of small GTPases...
August 12, 2017: DNA Repair
Huimin Fang, Liexiang Huangfu, Rujia Chen, Pengcheng Li, Shuhui Xu, Enying Zhang, Wei Cao, Li Liu, Youli Yao, Guohua Liang, Chenwu Xu, Yong Zhou, Zefeng Yang
The origin and evolution of land plants was an important event in the history of life and initiated the establishment of modern terrestrial ecosystems. From water to terrestrial environments, plants needed to overcome the enhanced ultraviolet (UV) radiation and many other DNA-damaging agents. Evolving new genes with the function of DNA repair is critical for the origin and radiation of land plants. In bacteria, the DNA-3-methyladenine glycosylase (MAG) recognizes of a variety of base lesions and initiates the process of the base excision repair for damaged DNA...
August 24, 2017: Scientific Reports
Andrea Sahlmann, Raoul Wolf, Tor Fredrik Holth, Josefin Titelman, Ketil Hylland
Anthropogenic pollutants produce oxidative stress in marine organisms, directly or following generation of reactive oxygen species (ROS), potentially resulting in increased accumulation of DNA strand breaks quantified. The aim of this study is to quantify baseline levels of DNA strand breaks in marine species from four phyla and to assess relative sensitivity to oxidative stress as well as ability to recover. DNA strand breaks were determined using a formamidopyrimidine DNA glycosylase (Fpg)-amended comet assay in circulating cells from blue mussel (Mytilus edulis), shore crab (Carcinus maenas), sea star (Asterias rubens), and vase tunicate (Ciona intestinalis)...
August 24, 2017: Journal of Toxicology and Environmental Health. Part A
Young Geun Mok, Ki Young Choi, Seung Hwan Hong, Jin Hoe Huh
DNA methylation is a prominent epigenetic modification in plants and animals regulated by similar mechanisms but the process of DNA demethylation is profoundly different. Unlike vertebrates that require a series of enzymatic conversions of 5-methylcytosine (5mC) into other bases for DNA demethylation, plants utilize the DEMETER (DME) family of 5mC DNA glycosylases to catalyze a direct removal of 5mC from DNA. Here we introduced Arabidopsis DME into human HEK-293T cells to allow direct 5mC excision, and observed that direct DNA demethylation activity was successfully implemented by DME expression...
August 22, 2017: Scientific Reports
Aaron M Fleming, Judy Zhu, Yun Ding, Cynthia J Burrows
Interplay between DNA repair of the oxidatively modified base 8-oxo-7,8-dihydroguanine (OG) and transcriptional activation has been documented in mammalian genes. Previously, we synthesized OG into the VEGF potential G-quadruplex sequence (PQS) in the coding strand of a luciferase promoter to identify that base excision repair (BER) unmasked the G-quadruplex (G4) fold for gene activation. In the present work, OG was site-specifically synthesized into a luciferase reporter plasmid to follow the time-dependent expression in mammalian cells when OG in the VEGF PQS context was located in the coding vs template strands of the luciferase promoter...
August 28, 2017: ACS Chemical Biology
Anton Slyvka, Karolina Mierzejewska, Matthias Bochtler
Thymine DNA glycosylase (TDG) and Nei-like 1 (NEIL1) have both been implicated in the base excision repair step of active DNA demethylation. The robust glycosylase activity of TDG on DNA substrates containing 5-formylcytosine (5fC) or 5-carboxylcytosine (5caC) is universally accepted, but the mode of action of NEIL1 is still debated. Based on genetic experiments, it has been suggested that NEIL1 acts redundantly with TDG and excises 5fC and 5caC directly. However, this result has been disputed, and it was suggested instead that NEIL1 is recruited by the monofunctional TDG for the 2'-deoxyribose excision step...
August 21, 2017: Scientific Reports
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