A Novel Role of DNA Polymerase η in Modulating Cellular Sensitivity to Chemotherapeutic Agents

Chen, Yih‐Wen; Cleaver, James E.; Hanaoka, Fumio; Chang, Che Shoa; Chou, Kai-Ming

doi:10.1158/1541-7786.mcr-05-0118

Cited by 114 publications

(122 citation statements)

References 28 publications

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“…Although results from yeast suggest that pol η does not confer resistance to ICL by cisplatin [5], XP-V cells have been reported to be hypersensitive to and impaired in the repair of a number of DNA damaging agents, including ICL-forming agents, suggesting that TLS by pol η is important in lesion tolerance and survival following ICL in humans [17,20,32,39]. However, most prior studies of pol η and ICLs have been performed utilizing plasmid substrates, rather than analyzing genomic DNA [18][19][20].…”

Section: Discussionmentioning

confidence: 99%

DNA polymerase η reduces the γ-H2AX response to psoralen interstrand crosslinks in human cells

Mogi

Butcher

2008

Experimental Cell Research

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DNA interstrand crosslinks are processed by multiple mechanisms whose relationships to each other are unclear. Xeroderma pigmentosum-variant (XP-V) cells lacking DNA polymerase η are sensitive to psoralen photoadducts created under conditions favoring crosslink formation, suggesting a role for translesion synthesis in crosslink repair. Because crosslinks can lead to double strand breaks, we monitored phosphorylated H2AX (γ-H2AX), which is typically generated near double-strand breaks but also in response to single-stranded DNA, following psoralen photoadduct formation in XP-V fibroblasts to assess whether polymerase η is involved in processing crosslinks. In contrast to conditions favoring monoadducts, conditions favoring psoralen crosslinks induced γ-H2AX levels in both XP-V and nucleotide excision repair-deficient XP-A cells relative to control repair-proficient cells; ectopic expression of polymerase η in XP-V cells normalized the γ-H2AX response. In response to psoralen crosslinking, γ-H2AX as well as 53BP1 formed co-incident foci that were more numerous and intense in XP-V and XP-A cells than in controls. Psoralen photoadducts induced γ-H2AX throughout the cell cycle in XP-V cells. These results indicate that polymerase η is important in responding to psoralen crosslinks, and are consistent with a model in which nucleotide excision repair and polymerase η are involved in processing crosslinks and avoiding γ-H2AX associated with double strand breaks and single-stranded DNA in human cells.

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Section: Discussionmentioning

confidence: 99%

DNA polymerase η reduces the γ-H2AX response to psoralen interstrand crosslinks in human cells

Mogi

Butcher

2008

Experimental Cell Research

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“…hpol is also involved in translesion synthesis of other DNA lesions, e.g. 8-oxodG (29, 30), abasic sites (31, 32), and cisplatin or other therapeutic drug-induced DNA damage (33)(34)(35)(36)(37)(38).In this study, we investigated the ability of hpol to incorporate ribonucleotides into DNA and crystallized hpol with incoming rNTPs opposite both undamaged DNA and an 8-oxodG lesion. Our results demonstrate that hpol can incorporate ribonucleotides into DNA with relatively high selectivity but low efficiency, even when the template strand contains the DNA lesion 8-oxodG or CPD.…”

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confidence: 99%

Mechanism of Ribonucleotide Incorporation by Human DNA Polymerase η

Egli

Guengerich

2016

Journal of Biological Chemistry

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Ribonucleotides and 2-deoxyribonucleotides are the basic units for RNA and DNA, respectively, and the only difference is the extra 2-OH group on the ribonucleotide sugar. Cellular rNTP concentrations are much higher than those of dNTP. When copying DNA, DNA polymerases not only select the base of the incoming dNTP to form a Watson-Crick pair with the template base but also distinguish the sugar moiety. Some DNA polymerases use a steric gate residue to prevent rNTP incorporation by creating a clash with the 2-OH group. Y-family human DNA polymerase (hpol ) is of interest because of its spacious active site (especially in the major groove) and tolerance of DNA lesions. Here, we show that hpol maintains base selectivity when incorporating rNTPs opposite undamaged DNA and the DNA lesions 7,8-dihydro-8-oxo-2-deoxyguanosine and cyclobutane pyrimidine dimer but with rates that are 10 3 -fold lower than for inserting the corresponding dNTPs. X-ray crystal structures show that the hpol scaffolds the incoming rNTP to pair with the template base (dG) or 7,8-dihydro-8-oxo-2-deoxyguanosine with a significant propeller twist. As a result, the 2-OH group avoids a clash with the steric gate, Phe-18, but the distance between primer end and P␣ of the incoming rNTP increases by 1 Å, elevating the energy barrier and slowing polymerization compared with dNTP. In addition, Tyr-92 was identified as a second line of defense to maintain the position of Phe-18. This is the first crystal structure of a DNA polymerase with an incoming rNTP opposite a DNA lesion.RNA and DNA are fundamental to life in all forms. The two nucleic acid polymers are composed of ribonucleotides and 2Ј-deoxyribonucleotides as the basic units, respectively. However, ribonucleotides have been found in DNA; they constitute a large proportion of the "DNA lesions" in the genome. In mice, they have been shown to be collectively the most frequently occurring DNA lesions, even more than abasic sites and 7,8-dihydro-8-oxo-2Ј-deoxyguanosine (8-oxodG).2 The presence of ribonucleotides in DNA increases the possibility of spontaneous hydrolysis, causing DNA to break more frequently. These ribonucleotides are mainly removed from DNA by the RNase H2 pathway (1-5). DNA polymerases introduce ribonucleotides into DNA by misinserting them (6). Concentrations of cellular rNTPs are 1-6 orders of magnitude higher than those of dNTPs, depending on the cell type and the stage of the cell cycle (6 -9). To discriminate dNTP from rNTP, a steric gate residue (typically a tyrosine or phenylalanine) is generally conserved in DNA polymerases and thought to create a clash with the extra hydroxyl group of the incoming rNTP (10 -17). Although limited in extent, ribonucleotide incorporation has still been observed by a variety of DNA polymerases, from replicative ones with relatively high fidelity and small active sites (e.g. pol ⑀ and pol ␦) to error-prone X-family pol and pol ␤ and Y-family pol (6,8,(17)(18)(19)(20)(21).Compared with other DNA polymerases, those in the Yfamily are known for high ...

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“…In addition to skin, pol η is expressed in most tissues (10). The expression of pol η correlates with the effectiveness of anticancer therapeutic agents that exert their activity by introducing DNA lesions that block the progression of DNA replication (11). In addition to exogenous introduced DNA lesions, pol η contributes to genomic stability during unperturbed DNA replication (12) and replicates across reactive oxygen species (ROS)-induced oxidative DNA lesions 8-oxoG (7,8-dihydro-8-oxoguanine), thymine glycol, and lipid peroxidation DNA adducts generated during endogenous metabolic processes (13,14).…”

mentioning

confidence: 99%

Ablation of XP-V gene causes adipose tissue senescence and metabolic abnormalities

Chen

Harris

Hatahet

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Obesity and the metabolic syndrome have evolved to be major health issues throughout the world. Whether loss of genome integrity contributes to this epidemic is an open question. DNA polymerase η (pol η), encoded by the xeroderma pigmentosum (XP-V) gene, plays an essential role in preventing cutaneous cancer caused by UV radiation-induced DNA damage. Herein, we demonstrate that pol η deficiency in mice (pol η −/− ) causes obesity with visceral fat accumulation, hepatic steatosis, hyperleptinemia, hyperinsulinemia, and glucose intolerance. In comparison to WT mice, adipose tissue from pol η −/− mice exhibits increased DNA damage and a greater DNA damage response, indicated by upregulation and/or phosphorylation of ataxia telangiectasia mutated (ATM), phosphorylated H 2 AX (γH 2 AX), and poly[ADP-ribose] polymerase 1 (PARP-1). Concomitantly, increased cellular senescence in the adipose tissue from pol η −/− mice was observed and measured by up-regulation of senescence markers, including p53, p16 Ink4a , p21, senescence-associated (SA) β-gal activity, and SA secretion of proinflammatory cytokines interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) as early as 4 wk of age. Treatment of pol η −/− mice with a p53 inhibitor, pifithrin-α, reduced adipocyte senescence and attenuated the metabolic abnormalities. Furthermore, elevation of adipocyte DNA damage with a high-fat diet or sodium arsenite exacerbated adipocyte senescence and metabolic abnormalities in pol η −/− mice. In contrast, reduction of adipose DNA damage with N-acetylcysteine or metformin ameliorated cellular senescence and metabolic abnormalities. These studies indicate that elevated DNA damage is a root cause of adipocyte senescence, which plays a determining role in the development of obesity and insulin resistance.T he human genome is constantly challenged by exogenous and endogenous DNA damaging agents. To ensure genome integrity, human cells have faithful DNA replication machinery and DNA repair systems that are coordinated by DNA damage response networks. In response to different extents or types of DNA lesions, the DNA damage response activates appropriate cellular responses, including transient or permanent (senescence) cell cycle arrest, or apoptosis, to minimize the detrimental effects of DNA lesions (1). Reduction or deficiency in DNA repair/replication enzyme activity is well documented to increase vulnerability for the development of cancer, neurodegenerative diseases, and aging (2). In addition, defective DNA repair enzymes are associated with the metabolic symptom; for example, DNA glycosylase (Neil1)-and OGG1-deficient mice are obese (3-5), and nucleotide excision repair protein ERCC1-XPF deficiency causes lipodystrophy (6). Furthermore, DNA damage response protein ataxia telangiectasia mutated (ATM) suppresses JNK activity through p53 signaling and mediates an antioxidant action that has been suggested to be relevant to the metabolic syndrome (7). Nucleotide excision repair XP-A protein may affect metabolism by altering mitochondrial...

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A Novel Role of DNA Polymerase η in Modulating Cellular Sensitivity to Chemotherapeutic Agents

Cited by 114 publications

References 28 publications

DNA polymerase η reduces the γ-H2AX response to psoralen interstrand crosslinks in human cells

DNA polymerase η reduces the γ-H2AX response to psoralen interstrand crosslinks in human cells

Mechanism of Ribonucleotide Incorporation by Human DNA Polymerase η

Ablation of XP-V gene causes adipose tissue senescence and metabolic abnormalities

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