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BER pathway

Teresa Morales-Ruiz, Álvaro C Romero-Valenzuela, Vanessa M Vázquez-Grande, Teresa Roldán-Arjona, Rafael R Ariza, Dolores Córdoba-Cañero
Base excision repair (BER) is a major defense pathway against spontaneous DNA damage. This multistep process is initiated by DNA glycosylases that recognise and excise the damaged base, and proceeds by the concerted action of additional proteins that perform incision of the abasic site, gap filling and ligation. BER has been extensively studied in bacteria, yeasts and animals. Although knowledge of this pathway in land plants is increasing, there are no reports detecting BER in algae. We describe here an experimental in vitro system allowing the specific analysis of BER in the model alga Chlamydomonas reinhardtii...
March 5, 2018: DNA Repair
Luz I Valenzuela-García, Víctor M Ayala-García, Ana G Regalado-García, Peter Setlow, Mario Pedraza-Reyes
The absence of base excision repair (BER) proteins involved in processing ROS-promoted genetic insults activates a DNA damage scanning (DisA)-dependent checkpoint event in outgrowing Bacillus subtilis spores. Here, we report that genetic disabling of transcription-coupled repair (TCR) or nucleotide excision repair (NER) pathways severely affected outgrowth of ΔdisA spores, and much more so than the effects of these mutations on log phase growth. This defect delayed the first division of spore's nucleoid suggesting that unrepaired lesions affected transcription and/or replication during outgrowth...
March 13, 2018: MicrobiologyOpen
Xiang Cao, Yi Zhou, Hongfang Sun, Miao Xu, Xiaowen Bi, Zhihui Zhao, Binghui Shen, Fengyi Wan, Zhuan Hong, Lei Lan, Lan Luo, Zhigang Guo, Zhimin Yin
Non-small cell lung cancer (NSCLC) patients harboring EGFR-activating mutations initially respond to EGFR tyrosine kinase inhibitors (EGFR-TKIs) and have shown favorable outcomes. However, acquired drug resistance to EGFR-TKIs develops in almost all patients mainly due to the EGFR T790 M mutation. Here, we show that treatment with low-dose EGFR-TKI results in the emergence of the EGFR T790 M mutation and in the reduction of HSP70 protein levels in HCC827 cells. Erlotinib treatment inhibits HSP70 phosphorylation at tyrosine 41 and increases HSP70 ubiquitination, resulting in HSP70 degradation...
March 7, 2018: Cancer Letters
Nidhi Sharma, Srinivas Chakravarthy, Matthew J Longley, William C Copeland, Aishwarya Prakash
The 16.5 kb mitochondrial genome is subjected to damage from reactive oxygen species (ROS) generated in the cell during normal cellular metabolism and external sources such as ionizing radiation and ultraviolet light. ROS cause harmful damage to DNA bases that could result in mutagenesis and various diseases, if not properly repaired. The base excision repair (BER) pathway is the primary pathway involved in maintaining the integrity of mtDNA. Several enzymes that partake in BER within the nucleus have also been identified in the mitochondria...
March 6, 2018: DNA Repair
Carlos H Trasviña-Arenas, Noe Baruch-Torres, Francisco J Cordoba-Andrade, Víctor M Ayala-García, Paola L García-Medel, Corina Díaz-Quezada, Antolín Peralta-Castro, José Juan Ordaz-Ortiz, Luis G Brieba
Plant mitochondrial and chloroplast genomes encode essential proteins for oxidative phosphorylation and photosynthesis. For proper cellular function, plant organelles must ensure genome integrity. Although plant organelles repair damaged DNA using the multi-enzyme Base Excision Repair (BER) pathway, the details of this pathway in plant organelles are largely unknown. The initial enzymatic steps in BER produce a 5'-deoxyribose phosphate (5'-dRP) moiety that must be removed to allow DNA ligation and in plant organelles, the enzymes responsible for the removal of a 5'-dRP group are unknown...
February 27, 2018: DNA Repair
Barbara Bukowska, Boleslaw T Karwowski
The clustered DNA lesions are a characteristic feature of ionizing radiation and are defined as two or more damage sites formed within 20 bps after the passage of a single radiation track. The clustered DNA lesions are divided into two major groups: double-stranded breaks (DSBs) and non-DSB clusters also known as Oxidatively-induced Clustered DNA Lesions (OCDLs), which could involve either two opposing strands or the same strand. As irradiation is gaining greater interest in cancer treatment as well as in imaging techniques, the detailed knowledge of its genotoxicity and the mechanisms of repair of radiation-induced DNA damage remain issues to explore...
February 25, 2018: Current Medicinal Chemistry
Olga A Kladova, Milena Bazlekowa-Karaban, Sonia Baconnais, Olivier Piétrement, Alexander A Ishchenko, Bakhyt T Matkarimov, Danila A Iakovlev, Andrey Vasenko, Olga S Fedorova, Eric Le Cam, Barbara Tudek, Nikita A Kuznetsov, Murat Saparbaev
The base excision repair (BER) pathway consists of sequential action of DNA glycosylase and apurinic/apyrimidinic (AP) endonuclease necessary to remove a damaged base and generate a single-strand break in duplex DNA. Human multifunctional AP endonuclease 1 (APE1, a.k.a. APEX1, HAP-1, or Ref-1) plays essential roles in BER by acting downstream of DNA glycosylases to incise a DNA duplex at AP sites and remove 3'-blocking sugar moieties at DNA strand breaks. Human 8-oxoguanine-DNA glycosylase (OGG1), methyl-CpG-binding domain 4 (MBD4, a...
February 11, 2018: DNA Repair
Akula Deepa, Kodipelli Naveena, Roy Anindya
Iron deprivation induces transcription of genes required for iron uptake and transcription factor Aft1 and Aft2 mediate this by regulating transcriptional program in S. cerevisiae. Iron-dependent Fe(II) and 2-oxoglutarate-dependent dioxygenase family proteins are involved in various cellular pathways including DNA alkylation damage repair. Whether Aft1/Aft2 are required for DNA alkylation repair is currently unknown. In this report, we have analyzed DNA alkylation repair under iron-deprived condition. S. cerevisiae Tpa1 is a member of Fe(II) and 2-oxoglutarate-dependent dioxygenase family and we show that deletion of AFT1 and AFT2 genes affects Tpa1 function resulting in sensitivity to alkylating agent MMS...
February 9, 2018: FEMS Yeast Research
Jin Liu, Xiaodan Zhao, Dandan Pei, Guo Sun, Ye Li, Chunhui Zhu, Cui Qiang, Junyi Sun, Jianfeng Shi, Yan Dong, Jianzhong Gou, Sicen Wang, Ang Li
Coptidis Rhizoma binds to the membrane receptors on hPDLSC/CMC, and the active ingredient Berberine (BER) that can be extracted from it may promote the proliferation and osteogenesis of periodontal ligament stem cells (hPDLSC). The membrane receptor that binds with BER on the cell surface of hPDLSC, the mechanism of direct interaction between BER and hPDLSC, and the related signal pathway are not yet clear. In this research, EGFR was screened as the affinity membrane receptor between BER and hPDLSC, through retention on CMC, competition with BER and by using a molecular docking simulation score...
February 12, 2018: Scientific Reports
Yunes Panahi, Amir Fattahi, Hamid Reza Nejabati, Sina Abroon, Zeinab Latifi, Abolfazl Akbarzadeh, Tohid Ghasemnejad
Sulfur mustard (SM) is an alkylating agent that causes severe damages to the skin, eyes, and the respiratory system. DNA alkylation is one of the most critical lesions that could lead to monoadducts and cross-links, as well as DNA strand breaks. In response to these adducts, cells initiate a series of reactions to recruit specific DNA repair pathways. The main DNA repair pathways in human cells, which could be involved in the DNA SM-induced DNA damages, are base excision repair (BER), nucleotide excision repair (NER), homologous recombination (HR) and non-homologous end joining (NHEJ)...
February 2, 2018: Environmental Toxicology and Pharmacology
Xiaolong Zhou, Wentao Wang, Chengtao Du, Feifei Yan, Songbai Yang, Ke He, Han Wang, Ayong Zhao
OGG1 is the first enzyme in the base excision repair pathway (BER) responsible for repairing 8-oxoguanine DNA lesions. Recent studies found that OGG1 may also be involved in epigenetic regulation. In this study, we focused on the roles of OGG1 in histone modification. First, to study the effects of OGG1 on histone modification, the protein levels of symmetric dimethylation of histone H4 arginine-3 (H4R3me2s) were determined by western blot analysis following the knockdown or overexpression of OGG1. Second, the molecular mechanisms by which OGG1 regulates H4R3me2s were assessed by co-immunoprecipitation (CO-IP) assays in mouse embryonic fibroblast (MEF) wild-type (WT) and Ogg-/- cells...
February 2, 2018: Molecular and Cellular Probes
Xiao-Li Yang, Shuai Zhang, Hua Li, Li-Min Zhang, Hai-Liang Song, Ya-Wen Wang
Few studies have been performed on both the potential and the risks of biofilm-electrode reactors (BERs) with regard to the removal of antibiotics. This study used 33 BERs to investigate the removal rate and degradation pathway of sulfadiazine (SDZ). Furthermore, the effects of additional electrons on sul genes and microbial community composition were examined. The study found that rapid elimination rates of 20mg/L SDZ were observed during the first 3h with different DC voltage rates. Even high concentrations (160mg/L) could be rapidly removed after 24h of system operation...
February 1, 2018: Ecotoxicology and Environmental Safety
Radha Yadav, Showkat Ahmad Lone, Kishor Gaikwad, Nagendra Kumar Singh, Jasdeep Chatrath Padaria
Ziziphus nummularia (Burm.f.) Wight & Arn., a perennial shrub that thrives in the arid regions, is naturally tolerant to drought. However, there are limited studies on the genomics of drought tolerance in Ziziphus sp. In this study, RNA-sequencing of one month old seedlings treated with PEG 6000 was performed using Roche GS-FLX454 Titanium pyrosequencing. A total of 367,176 raw sequence reads were generated, and upon adapter trimming and quality filtration 351,872 reads were assembled de novo into 32,739 unigenes...
February 5, 2018: Scientific Reports
Qifu Fan, Xin Xu, Xi Zhao, Qian Wang, Wei Xiao, Ying Guo, Yu V Fu
DNA repair is essential to maintain genome integrity. In addition to various DNA repair pathways dealing with specific types of DNA lesions, DNA damage tolerance (DDT) promotes the bypass of DNA replication blocks encountered by the replication fork to prevent cell death. Budding yeast Rad5 plays an essential role in the DDT pathway and its structure indicates that Rad5 recognizes damaged DNA or stalled replication forks, suggesting that Rad5 plays an important role in the DDT pathway choice. It has been reported that Rad5 forms subnuclear foci in the presence of methyl methanesulfonate (MMS) during the S phase...
February 2, 2018: Current Genetics
Jill M Beaver, Yanhao Lai, Shantell J Rolle, Liwei Weng, Marc M Greenberg, Yuan Liu
Oxidative DNA damage and base excision repair (BER) play important roles in modulating trinucleotide repeat (TNR) instability that is associated with human neurodegenerative diseases and cancer. We have reported that BER of base lesions can lead to TNR instability. However, it is unknown if modifications of the sugar in an abasic lesion modulate TNR instability. In this study, we characterized the effects of the oxidized sugar, 5'-(2-phosphoryl-1,4-dioxobutane)(DOB) in CAG repeat tracts on the activities of key BER enzymes, as well as on repeat instability...
2018: PloS One
Jiajie Yan, Weiwei Zhao, Justin K Thomson, Xianlong Gao, Dominic M DeMarco, Elena Carrillo, Biyi Chen, Xiaomin Wu, Kenneth S Ginsburg, Mamdouh Bakhos, Donald M Bers, Mark E Anderson, Long-Sheng Song, Michael Fill, Xun Ai
<u>Rationale:</u> Atrial fibrillation (AF) is the most common arrhythmia and advanced age is an inevitable and predominant AF risk factor. However, the mechanisms that couple aging and AF propensity remain unclear, making targeted therapeutic interventions unattainable. <u>Objective:</u> To explore the functional role of an important stress-response c-Jun N-terminal kinase (JNK) in sarcoplasmic reticulum (SR) Ca2+ handling and consequently Ca2+ -mediated atrial arrhythmias. <u>Methods and Results:</u> We employed a series of cutting-edge electrophysiological and molecular techniques, exploited the power of transgenic mouse models to detail the molecular mechanism, and verified its clinical applicability in parallel studies on donor human hearts...
January 19, 2018: Circulation Research
Katalin Sas, Elza Szabó, László Vécsei
In this review, the potential causes of ageing are discussed. We seek to gain insight into the main physiological functions of mitochondria and discuss alterations in their function and the genome, which are supposed to be the central mechanisms in senescence. We conclude by presenting the potential modulating role of the kynurenine pathway in the ageing processes. Mitochondrial dynamics are supposed to have important physiological roles in maintaining cell homeostasis. During ageing, a decrease in mitochondrial dynamics was reported, potentially compromising the function of mitochondria...
January 17, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Melissa R Koch, Nealia C M House, Casey M Cosetta, Robyn M Jong, Christelle G Salomon, Cailin E Joyce, Elliot A Philips, Xiaofeng A Su, Catherine H Freudenreich
CAG/CTG trinucleotide repeats are unstable sequences that are difficult to replicate, repair, and transcribe due to their structure-forming nature. CAG repeats strongly position nucleosomes; however, little is known about the chromatin remodeling needed to prevent repeat instability. In a Saccharomyces cerevisiae model system with CAG repeats carried on a YAC, we discovered that the chromatin remodeler Isw1 is required to prevent CAG repeat expansions during transcription. CAG repeat expansions in the absence of Isw1 were dependent on both transcription-coupled repair (TCR) and base-excision repair (BER)...
March 2018: Genetics
Liyan Zhou, Wei Wang, Chuan Yang, Tingting Zeng, Mengdie Hu, Xiaoyi Wang, Na Li, Kan Sun, Chuan Wang, Jing Zhou, Meng Ren, Li Yan
Diabetes elevates matrix metalloproteinase-9 (MMP-9) levels in the skin and its keratinocytes, and activated MMP-9 impairs skin wound healing. Epigenetic regulation of the DNA methylation status within the MMP-9 promoter plays an important role in the alteration of MMP-9 expression. Our aim was to investigate the role and mechanism of growth arrest and DNA damage-inducible 45a (GADD45a), a well-known DNA demethylation regulatory protein that mediates DNA methylation, in the regulation of MMP-9 expression. In this study, we showed that GADD45a was markedly upregulated in skin tissues from patients with diabetic foot ulcers, in diabetic rats and in human keratinocyte (HaCaT) cells exposed to advanced glycation end products (AGEs)...
December 13, 2017: Endocrinology
Henok Kassahun, Tanima SenGupta, Alfonso Schiavi, Silvia Maglioni, Hanne K Skjeldam, Katarzyna Arczewska, Nicole L Brockway, Suzanne Estes, Lars Eide, Natascia Ventura, Hilde Nilsen
Oxidation of DNA bases, an inevitable consequence of oxidative stress, requires the base excision repair (BER) pathway for repair. Caenorhabditis elegans is a well-established model to study phenotypic consequences and cellular responses to oxidative stress. To better understand how BER affects phenotypes associated with oxidative stress, we characterised the C. elegans nth-1 mutant, which lack the only DNA glycosylase dedicated to repair of oxidative DNA base damage, the NTH-1 DNA glycosylase. We show that nth-1 mutants have mitochondrial dysfunction characterised by lower mitochondrial DNA copy number, reduced mitochondrial membrane potential, and increased steady-state levels of reactive oxygen species...
January 2018: DNA Repair
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