Read by QxMD icon Read

DNA glycosylases

Lang Pan, Bing Zhu, Wenjing Hao, Xianlu Zeng, Spiros A Vlahopoulos, Tapas K Hazra, Muralidhar L Hegde, Zsolt Radak, Attila Bacsi, Allan R Brasier, Xueqing Ba, Istvan Boldogh
A large percentage of redox-responsive gene promoters contain evolutionarily conserved guanine-rich clusters; guanines are the bases most susceptible to oxidative modification(s). Consequently, 7,8-dihydro-8-oxoguanine (8-oxoG) is one of the most abundant base lesions in promoters and is primarily repaired via the 8-oxoguanine DNA glycosylase1 (OOG1)-initiated base excision repair pathway. In view of a prompt cellular response to oxidative challenge, we hypothesized that the 8-oxoG lesion and the cognate repair protein OGG1 are utilized in transcriptional gene activation...
October 18, 2016: Journal of Biological Chemistry
Ana Marques, Andreia Rego, Sofia Guilherme, Isabel Gaivão, Maria Ana Santos, Mário Pacheco
The formulation Mancozan(®), containing mancozeb as active ingredient, is among the most widely used fungicides. Although mancozeb has been detected in surface waters, studies addressing the genotoxic risk to fish arising from the use of this formulation, testing environmentally realistic concentrations, are absent from the literature. Hence, this work aimed to investigate the DNA and chromosome damaging potential of Mancozan(®) (0.29 and 2.9μgL(-1)) in the European eel (Anguilla anguilla L.), after a short-term exposure (3days), through the adoption of the comet and the erythrocytic nuclear abnormality (ENA) assays...
October 2016: Pesticide Biochemistry and Physiology
Delong Wang, Ken-Ichi Miyazono, Masaru Tanokura
R.PabI is a type II restriction enzyme that recognizes the 5'-GTAC-3' sequence and belongs to the HALFPIPE superfamily. Although most restriction enzymes cleave phosphodiester bonds at specific sites by hydrolysis, R.PabI flips the guanine and adenine bases of the recognition sequence out of the DNA helix and hydrolyzes the N-glycosidic bond of the flipped adenine in a similar manner to DNA glycosylases. In this study, we determined the structure of R.PabI in complex with double-stranded DNA without the R.PabI recognition sequence by X-ray crystallography...
October 12, 2016: Scientific Reports
Yunqing Ma, Jiayuan Zhang, Weijie Yin, Zhenchao Zhang, Yan Song, Xing Chang
A large number of genetic variants have been associated with human diseases. However, the lack of a genetic diversification approach has impeded our ability to interrogate functions of genetic variants in mammalian cells. Current screening methods can only be used to disrupt a gene or alter its expression. Here we report the fusion of activation-induced cytidine deaminase (AID) with nuclease-inactive clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (dCas9) for efficient genetic diversification, which enabled high-throughput screening of functional variants...
October 10, 2016: Nature Methods
Javier Abellón-Ruiz, Sonoko Ishino, Yoshizumi Ishino, Bernard A Connolly
In Archaea repair of uracil and hypoxanthine, which arise by deamination of cytosine and adenine, respectively, is initiated by three enzymes: Uracil-DNA-glycosylase (UDG, which recognises uracil); Endonuclease V (EndoV, which recognises hypoxanthine); and Endonuclease Q (EndoQ), (which recognises both uracil and hypoxanthine). Two archaeal DNA polymerases, Pol-B and Pol-D, are inhibited by deaminated bases in template strands, a feature unique to this domain. Thus the three repair enzymes and the two polymerases show overlapping specificity for uracil and hypoxanthine...
2016: Archaea: An International Microbiological Journal
Jyoti Singh Tomar, Manju Narwal, Pravindra Kumar, Rama Krishna Peddinti
The rise of multiple-drug resistance in bacterial pathogens imposes a serious public health concern and has led to increased interest in studying various pathways as well as enzymes. Different DNA glycosylases collaborate during bacterial infection and disease by overcoming the effects of ROS- and RNS-mediated host innate immunity response. 3-Methyladenine DNA glycosylase I, an essential DNA repair enzyme, was chosen for the present study from the MDR species of A. baumannii. The enzyme was especially chosen because of its functional significance in A...
September 26, 2016: Molecular BioSystems
Hesbon Z Amenya, Chiharu Tohyama, Seiichiroh Ohsako
The aryl hydrocarbon receptor (Ahr) is a highly conserved nuclear receptor that plays an important role in the manifestation of toxicity induced by polycyclic aromatic hydrocarbons. As a xenobiotic sensor, Ahr is involved in chemical biotransformation through activation of drug metabolizing enzymes. The activated Ahr cooperates with coactivator complexes to induce epigenetic modifications at target genes. Thus, it is conceivable that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a potent Ahr ligand, may elicit robust epigenetic changes in vivo at the Ahr target gene cytochrome P450 1a1 (Cyp1a1)...
October 7, 2016: Scientific Reports
Serkalem Tadesse, Nicholas G Norwitz, Seth Guller, Felice Arcuri, Paolo Toti, Errol R Norwitz, Dawit Kidane
Preeclampsia (PE) (gestational proteinuric hypertension) is the leading cause of maternal and perinatal mortality worldwide. Although placental endothelial dysfunction and oxidative stress are known to contribute to PE, the exact pathological basis for this disorder remains unclear. Previously, we demonstrated that DNA damage at the maternal-fetal interface is more common in the placentas of women with PE than normotensive controls. In this study, we utilized an in vivo comparative study, including 20 preeclamptic women and 8 healthy control subjects, and an in vitro hypoxia/reperfusion model to mimic the effects of oxidative stress at the maternal-fetal interface...
October 5, 2016: Reproductive Sciences
Iyo Shiraishi, Naoya Shikazono, Masao Suzuki, Kentaro Fujii, Akinari Yokoya
PURPOSE: To clarify whether initial base excision repair processes at clustered DNA damage sites comprising multiple base lesions affect subsequent excision processes via the formation of additional strand breaks by glycosylase and apurinic/apyrimidinic (AP) endonuclease base excision enzymes. MATERIALS AND METHODS: Plasmid DNA (pUC18) as a model DNA molecule was exposed to high-linear-energy-transfer (LET) ionizing radiation (He(2+) or C(6+) ions) or low-LET ionizing radiation (X-rays) under various conditions to produce varied radical-scavenging effects...
October 6, 2016: International Journal of Radiation Biology
Li-Bin Ling, Yung Chang, Chia-Wei Liu, Po-Ling Lai, Todd Hsu
Our earlier studies showed the inhibitory effects of cadmium (Cd) and paraquat (PQ) on the gene expression of DNA mismatch recognition proteins in zebrafish (Danio rerio) embryos. This study explored the effects of Cd and PQ on nucleotide excision repair (NER) capacity in zebrafish embryos. Exposure of embryos at 1 h post fertilization (hpf) to 3-5 μM Cd or 30-100 μM PQ for 9 h induced a 2-3-fold increase of oxidative stress, while a 6.5-fold increase of oxidative stress was induced by 200 μM PQ. Real-time RT-PCR detected a down-regulated xeroderma pigmentosum C (XPC) and an up-regulated UV-DDB2 gene expression in mildly-stressed embryos, whereas 8-oxoguanine DNA glycosylase (OGG1) gene expression increased with PQ exposure levels...
October 2, 2016: Chemosphere
Mélanie Flaender, Guillaume Costa, Guillaume Nonglaton, Christine Saint-Pierre, Didier Gasparutto
DNA is under continuous assault by environmental and endogenous reactive oxygen and alkylating species, inducing the formation of mutagenic, toxic and genome destabilizing nucleobase lesions. Due to the implications of such genetic alterations in cell death, aging, inflammation, neurodegenerative diseases and cancer, many efforts have been devoted to developing assays that aim at analyzing DNA repair activities from purified enzymes or cell extracts. The present work deals with the conception and application of a new, miniaturized and parallelized on surface-DNA biosensor to measure base excision repair (BER) activities...
September 22, 2016: Analyst
Víctor M Ayala-García, Luz I Valenzuela-García, Peter Setlow, Mario Pedraza-Reyes
: Aag from B. subtilis has been implicated in in vitro removal of hypoxanthine and alkylated bases from DNA. The regulation of expression of aag in B. subtilis, and the resistance to genotoxic agents and mutagenic properties of an Aag-deficient strain were studied here. A strain with a transcriptional aag-lacZ fusion expressed low levels of β-galactosidase during growth and early sporulation but exhibited increased transcription during late stages of this developmental process. Notably, aag-lacZ expression was higher inside the forespore than in the mother cell compartment and this expression was abolished in a sigG-deficient background suggesting a forespore-specific mechanism of aag transcription...
October 3, 2016: Journal of Bacteriology
Elena M Cortizas, Astrid Zahn, Shiva Safavi, Joseph A Reed, Francisco Vega, Javier M Di Noia, Ramiro E Verdun
Activation-induced deaminase (AID) initiates antibody gene diversification by creating G:U mismatches in the immunoglobulin loci. However, AID also deaminates nonimmunoglobulin genes, and failure to faithfully repair these off-target lesions can cause B cell lymphoma. In this study, we identify a mechanism by which processing of G:U produced by AID at the telomeres can eliminate B cells at risk of genomic instability. We show that telomeres are off-target substrates of AID and that B cell proliferation depends on protective repair by uracil-DNA glycosylase (UNG)...
October 3, 2016: Journal of Experimental Medicine
Barbara S Janović, Andrew R Collins, Zoran M Vujčić, Miroslava T Vujčić
The aim of this study was to investigate the impact of dyes on DNA before and after enzymatic decolorization by acidic horseradish peroxidase (HRP-A). The comet assay is easy and feasible method widely used to measure DNA damage and repair. The medium-throughput comet assay was employed for assessment of genotoxic effects of 8 dyes in BEAS-2B cells. We have incorporated a digestion with bacterial endonuclease (formamidopyrimidine DNA glycosylase, FPG) to detect oxidized bases in the case of single and double azo dyes, Orange II (OR2) and Amido Black 10B (AB), respectively...
September 23, 2016: Journal of Hazardous Materials
Daniel R Semlow, Jieqiong Zhang, Magda Budzowska, Alexander C Drohat, Johannes C Walter
During eukaryotic DNA interstrand cross-link (ICL) repair, cross-links are resolved ("unhooked") by nucleolytic incisions surrounding the lesion. In vertebrates, ICL repair is triggered when replication forks collide with the lesion, leading to FANCI-FANCD2-dependent unhooking and formation of a double-strand break (DSB) intermediate. Using Xenopus egg extracts, we describe here a replication-coupled ICL repair pathway that does not require incisions or FANCI-FANCD2. Instead, the ICL is unhooked when one of the two N-glycosyl bonds forming the cross-link is cleaved by the DNA glycosylase NEIL3...
October 6, 2016: Cell
Norbert Schormann, Natalia Zhukovskaya, Gregory Bedwell, Manunya Nuth, Richard Gillilan, Peter E Prevelige, Robert P Ricciardi, Surajit Banerjee, Debasish Chattopadhyay
Uracil-DNA glycosylases are ubiquitous enzymes, which play a key role repairing damages in DNA and in maintaining genomic integrity by catalyzing the first step in the base excision repair pathway. Within the superfamily of uracil-DNA glycosylases family I enzymes or UNGs are specific for recognizing and removing uracil from DNA. These enzymes feature conserved structural folds, active site residues and use common motifs for DNA binding, uracil recognition and catalysis. Within this family the enzymes of poxviruses are unique and most remarkable in terms of amino acid sequences, characteristic motifs and more importantly for their novel non-enzymatic function in DNA replication...
September 29, 2016: Protein Science: a Publication of the Protein Society
Hongxu Zhang, Jianguang Zhong, Zhenyu Bian, Xiang Fang, You Peng, Yongping Hu
BACKGROUND: Evidences have identified the correlation of 8-oxoguanine DNA glycosylase-1 (OGG1) and eph-receptor tyrosine kinase-type A2 (EPHA2) polymorphisms in age-related cataract (ARC) risk. However, the results were not consistent. The objective of this study was to examine the role of these two gene polymorphisms in ARC susceptibility. METHODS: Eligible case-control studies published between January 2000 and 2015 were searched and retrieved in the electronic databases...
September 29, 2016: BMC Ophthalmology
Akira Sassa, Melike Ҫağlayan, Yesenia Rodriguez, William A Beard, Samuel H Wilson, Takehiko Nohmi, Masamitsu Honma, Manabu Yasui
Numerous ribonucleotides are incorporated into the genome during DNA replication. Oxidized ribonucleotides can also be erroneously incorporated into DNA. Embedded ribonucleotides destabilize the structure of DNA and retard DNA synthesis by DNA polymerases (pols), leading to genomic instability. Mammalian cells possess translesion DNA synthesis (TLS) pols that bypass DNA damage. The mechanism of TLS and repair of oxidized ribonucleotides remains to be elucidated. To address this, we analyzed the miscoding properties of the ribonucleotides riboguanosine (rG) and 7,8-dihydro-8-oxo-riboguanosine (8-oxo-rG) during TLS catalyzed by the human TLS pols κ and η in vitro...
September 22, 2016: Journal of Biological Chemistry
Giuseppe La Rosa, Martin Zacharias
Oxidation of guanine (Gua) to form 7,8-dihydro-8-oxoguanine (8oxoG) is a frequent mutagenic DNA lesion. DNA repair glycosylases such as the bacterial MutM can effciently recognize and eliminate the 8oxoG damage by base excision. The base excision requires a 8oxoG looping out (flipping) from an intrahelical base paired to an extrahelical state where the damaged base is in the enzyme active site. It is still unclear how the damage is identified and flipped from an energetically stable stacked and paired state without any external energy source...
September 19, 2016: Nucleic Acids Research
Naile Dame-Teixeira, Clarissa Cavalcanti Fatturi Parolo, Marisa Maltz, Aradhna Tugnait, Deirdre Devine, Thuy Do
BACKGROUND: The studies of the distribution of Actinomyces spp. on carious and non-carious root surfaces have not been able to confirm the association of these bacteria with root caries, although they were extensively implicated as a prime suspect in root caries. OBJECTIVE: The aim of this study was to observe the gene expression of Actinomyces spp. in the microbiota of root surfaces with and without caries. DESIGN: The oral biofilms from exposed sound root surface (SRS; n=10) and active root caries (RC; n=30) samples were collected...
2016: Journal of Oral Microbiology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"