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translesion synthesis

Katrina Estep, Thomas J Butler, Jun Ding, Robert M Brosh
Guanine-rich DNA can fold into highly stable non-canonical four-stranded DNA structures called G-quadruplexes. These structures present obstacles for the DNA replication machinery, and it has been hypothesized that both eukaryotic DNA helicases and polymerases have evolved to resolve G4 DNA in vivo. Since the discovery of G-quadruplex DNA in the early 1960's, a number of studies have emerged reporting G-quadruplex DNA unfolding by helicase enzymes and DNA synthesis past G4 by specialized translesion polymerase enzymes...
November 16, 2017: Current Medicinal Chemistry
A V Ignatov, K A Bondarenko, A V Makarova
DNA damage is a major cause of replication interruption, mutations, and cell death. DNA damage is removed by several types of repair processes. The involvement of specialized DNA polymerases in replication provides an important mechanism that helps tolerate persistent DNA damage. Specialized DNA polymerases incorporate nucleotides opposite lesions with high efficiency but demonstrate low accuracy of DNA synthesis. In this review, we summarize the types and mechanisms of formation and repair of non-bulky DNA lesions, and we provide an overview of the role of specialized DNA polymerases in translesion DNA synthesis...
July 2017: Acta Naturae
Kenichi Masumura, Naomi Toyoda-Hokaiwado, Naoko Niimi, Petr Grúz, Naoko A Wada, Akira Takeiri, Kou-Ichi Jishage, Masayuki Mishima, Takehiko Nohmi
DNA polymerase kappa (Polk) is a specialized DNA polymerase involved in translesion DNA synthesis. To understand the protective roles against genotoxins in vivo, we established inactivated Polk knock-in gpt delta (inactivated Polk KI) mice that possessed reporter genes for mutations and expressed inactive Polk. In this study, we examined genotoxicity of benzo[a]pyrene (BP) to determine whether Polk actually suppressed BP-induced genotoxicity as predicted by biochemistry and in vitro cell culture studies. Seven-week-old inactivated Polk KI and wild-type (WT) mice were treated with BP at doses of 5, 15, or 50 mg/(kg·day) for three consecutive days by intragastric gavage, and mutations in the colon and micronucleus formation in the peripheral blood were examined...
October 27, 2017: Environmental and Molecular Mutagenesis
Derrick Sek Tong Ong, Baoli Hu, Yan Wing Ho, Charles-Etienne Gabriel Sauvé, Christopher A Bristow, Qianghu Wang, Asha S Multani, Peiwen Chen, Luigi Nezi, Shan Jiang, Claire Elizabeth Gorman, Marta Moreno Monasterio, Dimpy Koul, Matteo Marchesini, Simona Colla, Eun-Jung Jin, Erik P Sulman, Denise J Spring, Wai-Kwan Alfred Yung, Roel G W Verhaak, Lynda Chin, Y Alan Wang, Ronald A DePinho
An integrated genomic and functional analysis to elucidate DNA damage signaling factors promoting self-renewal of glioma stem cells (GSCs) identified proliferating cell nuclear antigen (PCNA)-associated factor (PAF) up-regulation in glioblastoma. PAF is preferentially overexpressed in GSCs. Its depletion impairs maintenance of self-renewal without promoting differentiation and reduces tumor-initiating cell frequency. Combined transcriptomic and metabolomic analyses revealed that PAF supports GSC maintenance, in part, by influencing DNA replication and pyrimidine metabolism pathways...
October 24, 2017: Proceedings of the National Academy of Sciences of the United States of America
Rubén Torregrosa-Muñumer, Josefin M E Forslund, Steffi Goffart, Annika Pfeiffer, Gorazd Stojkovič, Gustavo Carvalho, Natalie Al-Furoukh, Luis Blanco, Sjoerd Wanrooij, Jaakko L O Pohjoismäki
Eukaryotic PrimPol is a recently discovered DNA-dependent DNA primase and translesion synthesis DNA polymerase found in the nucleus and mitochondria. Although PrimPol has been shown to be required for repriming of stalled replication forks in the nucleus, its role in mitochondria has remained unresolved. Here we demonstrate in vivo and in vitro that PrimPol can reinitiate stalled mtDNA replication and can prime mtDNA replication from nonconventional origins. Our results not only help in the understanding of how mitochondria cope with replicative stress but can also explain some controversial features of the lagging-strand replication...
October 24, 2017: Proceedings of the National Academy of Sciences of the United States of America
Takashi Yagi, Yoshihiro Fujikawa, Tomoko Sawai, Takeji Takamura-Enya, Sayoko Ito-Harashima, Masanobu Kawanishi
Aryl hydrocarbons such as 3-nitrobenzanthrone (NBA), 4-aminobiphenyl (ABP), acetylaminofluorene (AAF), benzo(a)pyrene (BaP), and 1-nitropyrene (NP) form bulky DNA adducts when absorbed by mammalian cells. These chemicals are metabolically activated to reactive forms in mammalian cells and preferentially get attached covalently to the N(2) or C8 positions of guanine or the N(6) position of adenine. The proportion of N(2) and C8 guanine adducts in DNA differs among chemicals. Although these adducts block DNA replication, cells have a mechanism allowing to continue replication by bypassing these adducts: translesion DNA synthesis (TLS)...
October 2017: Toxicological Research
Elisabeth Karg, Martha Smets, Joel Ryan, Ignasi Forné, Weihua Qin, Christopher B Mulholland, Georgia Kalideris, Axel Imhof, Sebastian Bultmann, Heinrich Leonhardt
Ubiquitination is a multifunctional posttranslational modification controlling the activity, subcellular localization and stability of proteins. The E3 ubiquitin ligase UHRF1 is an essential epigenetic factor that recognizes repressive histone marks as well as hemi-methylated DNA and recruits DNMT1. To explore enzymatic functions of UHRF1 beyond epigenetic regulation we conducted a comprehensive screen in mouse embryonic stem cells to identify novel ubiquitination targets of UHRF1 and its paralogue UHRF2. We found differentially ubiquitinated peptides associated with a variety of biological processes such as transcriptional regulation and DNA damage response...
October 18, 2017: Journal of Molecular Biology
Olga Rechkoblit, Alexander Kolbanovskiy, Hannah Landes, Nicholas E Geacintov, Aneel K Aggarwal
Benzo[a]pyrene (BP) is a carcinogen in cigarette smoke which, after metabolic activation, can react with the exocyclic N (2) amino group of guanine to generate four stereoisomeric BP-N (2)-dG adducts. Rev1 is unique among translesion synthesis DNA polymerases in employing a protein-template-directed mechanism of DNA synthesis opposite undamaged and damaged guanine. Here we report high-resolution structures of yeast Rev1 with three BP-N (2)-dG adducts, namely the 10S (+)-trans-BP-N (2)-dG, 10R (+)-cis-BP-N (2)-dG, and 10S ( - )-cis-BP-N (2)-dG...
October 17, 2017: Nature Communications
Vamsi K Gali, Eva Balint, Nataliia Serbyn, Orsolya Frittmann, Francoise Stutz, Ildiko Unk
Polymerase eta (Polη) is a low fidelity translesion synthesis DNA polymerase that rescues damage-stalled replication by inserting deoxy-ribonucleotides opposite DNA damage sites resulting in error-free or mutagenic damage bypass. In this study we identify a new specific RNA extension activity of Polη of Saccharomyces cerevisiae. We show that Polη is able to extend RNA primers in the presence of ribonucleotides (rNTPs), and that these reactions are an order of magnitude more efficient than the misinsertion of rNTPs into DNA...
October 12, 2017: Scientific Reports
Sonali Bhattacharjee, Saikat Nandi
Fanconi Anemia (FA) is a rare, inherited genomic instability disorder, caused by mutations in genes involved in the repair of interstrand DNA crosslinks (ICLs). The FA signaling network contains a unique nuclear protein complex that mediates the monoubiquitylation of the FANCD2 and FANCI heterodimer, and coordinates activities of the downstream DNA repair pathway including nucleotide excision repair, translesion synthesis, and homologous recombination. FA proteins act at different steps of ICL repair in sensing, recognition and processing of DNA lesions...
October 10, 2017: Cell Communication and Signaling: CCS
Noe Baruch-Torres, Luis G Brieba
Genomes acquire lesions that can block the replication fork and some lesions must be bypassed to allow survival. The nuclear genome of flowering plants encodes two family-A DNA polymerases (DNAPs), the result of a duplication event, that are the sole DNAPs in plant organelles. These DNAPs, dubbed Plant Organellar Polymerases (POPs), resemble the Klenow fragment of bacterial DNAP I and are not related to metazoan and fungal mitochondrial DNAPs. Herein we report that replicative POPs from the plant model Arabidopsis thaliana (AtPolI) efficiently bypass one the most insidious DNA lesions, an apurinic/apyrimidinic (AP) site...
October 13, 2017: Nucleic Acids Research
Vanessa Y De La Rosa, Jonathan Asfaha, Michael Fasullo, Alex Loguinov, Peng Li, Lee E Moore, Nathaniel Rothman, Jun Nakamura, James A Swenberg, Ghislaine Scelo, Luoping Zhang, Martyn T Smith, Chris D Vulpe
Trichloroethylene (TCE), an industrial chemical and environmental contaminant, is a human carcinogen. Reactive metabolites are implicated in renal carcinogenesis associated with TCE exposure, yet the toxicity mechanisms of these metabolites and their contribution to cancer and other adverse effects remain unclear. We employed an integrated functional genomics approach that combined functional profiling studies in yeast and avian DT40 cell models to provide new insights into the specific mechanisms contributing to toxicity associated with TCE metabolites...
November 1, 2017: Toxicological Sciences: An Official Journal of the Society of Toxicology
Yan Su, Martin Egli, F Peter Guengerich
Ribonucleotides are the natural analogs of deoxyribonucleotides, which can be misinserted by DNA polymerases, leading to the most abundant DNA lesions in genomes. During replication, DNA polymerases tolerate patches of ribonucleotides on the parental strands to different extents. The majority of human DNA polymerases have been reported to misinsert ribonucleotides into genomes. However, only PrimPol, DNA polymerase α, telomerase, and the mitochondrial human DNA polymerase (hpol) γ have been shown to tolerate an entire RNA strand...
November 3, 2017: Journal of Biological Chemistry
Nima Borhan Fakouri, Jon Ambæk Durhuus, Christine Elisabeth Regnell, Maria Angleys, Claus Desler, Mahdi Hasan- Olive, Ana Martín-Pardillos, Anastasia Tsaalbi-Shtylik, Kirsten Thomsen, Martin Lauritzen, Vilhelm A Bohr, Niels de Wind, Linda Hildegard Bergersen, Lene Juel Rasmussen
Nucleic acids, which constitute the genetic material of all organisms, are continuously exposed to endogenous and exogenous damaging agents, representing a significant challenge to genome stability and genome integrity over the life of a cell or organism. Unrepaired DNA lesions, such as single- and double-stranded DNA breaks (SSBs and DSBs), and single-stranded gaps can block progression of the DNA replication fork, causing replicative stress and/or cell cycle arrest. However, translesion synthesis (TLS) DNA polymerases, such as Rev1, have the ability to bypass some DNA lesions, which can circumvent the process leading to replication fork arrest and minimize replicative stress...
October 2, 2017: Scientific Reports
Marina Raguse, Rubén Torres, Elena M Seco, Carolina Gándara, Silvia Ayora, Ralf Moeller, Juan C Alonso
The mechanisms that allow to circumvent replicative stress, and to resume DNA synthesis are poorly understood in Bacillus subtilis. To study the role of the diadenylate cyclase DisA and branch migration translocase (BMT) RadA/Sms in restarting a stalled replication fork, we nicked and broke the circular chromosome of an inert mature haploid spore, damaged the bases, and measured survival of reviving spores. During undisturbed ripening, nicks and breaks should be repaired by pathways that do not invoke long-range end resection or genetic exchange by homologous recombination, after which DNA replication might be initiated...
September 22, 2017: DNA Repair
Ji-Young Kim, Hee-Kyung Yoon, Seung Taek Song, Seok-Rae Park, Seung-Cheol Shim
To investigate the expression patterns of activation-induced cytidine deaminase (AID) variants in peripheral blood mononuclear cells (PBMCs) of patients with ankylosing spondylitis (AS) and examine their clinical implications, we isolated PBMCs from healthy controls (HC, n = 33) and patients with AS (n = 62), and measured mRNA expression of AID variants and translesion synthesis (TLS) polymerases using quantitative real-time polymerase chain reaction. The proportion of patients with AS in whom AID splicing variant (sv) 2 was expressed was significantly higher than that of HC (p = ...
September 29, 2017: Autoimmunity
Yizhang Chen, Tomohiko Sugiyama
Translesion synthesis (TLS) is the mechanism in which DNA polymerases (TLS polymerases) bypass unrepaired template damage with high error rates. DNA polymerase η and ζ (Polη and Polζ) are major TLS polymerases that are conserved from yeast to humans. In this study, we quantified frequencies of base-substitutions by yeast Polη and Polζ on undamaged and abasic templates in vitro. For accurate quantification, we used a next generation sequencing (NGS)-based method where DNA products were directly analyzed by parallel sequencing...
November 2017: DNA Repair
Jung-Hoon Yoon, Jayati Roy Choudhury, Jeseong Park, Satya Prakash, Louise Prakash
N3-Methyladenine (3-MeA) is formed in DNA by reaction with S-adenosylmethionine, the reactive methyl donor, and by reaction with alkylating agents. 3-MeA protrudes into the DNA minor groove and strongly blocks synthesis by replicative DNA polymerases (Pols). However, the mechanisms for replicating through this lesion in human cells remain unidentified. Here we analyzed the roles of translesion synthesis (TLS) Pols in the replication of 3-MeA-damaged DNA in human cells. Because 3-MeA has a short half-life in vitro, we used the stable 3-deaza analog, 3-deaza-3-methyladenine (3-dMeA), which blocks the DNA minor groove similarly to 3-MeA...
November 10, 2017: Journal of Biological Chemistry
Ingrid R Alves, Marco A Lima-Noronha, Larissa G Silva, Frank S Fernández-Silva, Aline Luiza D Freitas, Marilis V Marques, Rodrigo S Galhardo
imuABC (imuAB dnaE2) genes are responsible for SOS-mutagenesis in Caulobacter crescentus and other bacterial species devoid of umuDC. In this work, we have constructed operator-constitutive mutants of the imuABC operon. We used this genetic tool to investigate the effect of SOS-induced levels of these genes upon both spontaneous and damage-induced mutagenesis. We showed that constitutive expression of imuABC does not increase spontaneous or damage-induced mutagenesis, nor increases cellular resistance to DNA-damaging agents...
September 14, 2017: DNA Repair
Federica Bertoletti, Valentina Cea, Chih-Chao Liang, Taiba Lanati, Antonio Maffia, Mario D M Avarello, Lina Cipolla, Alan R Lehmann, Martin A Cohn, Simone Sabbioneda
DNA translesion synthesis (TLS) is a crucial damage tolerance pathway that oversees the completion of DNA replication in the presence of DNA damage. TLS polymerases are capable of bypassing a distorted template but they are generally considered inaccurate and they need to be tightly regulated. We have previously shown that polη is phosphorylated on Serine 601 after DNA damage and we have demonstrated that this modification is important for efficient damage bypass. Here we report that polη is also phosphorylated by CDK2, in the absence of damage, in a cell cycle-dependent manner and we identify serine 687 as an important residue targeted by the kinase...
September 19, 2017: Nucleic Acids Research
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