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Sample records for repair genes arsenic

  1. [Polymorphism of genes encoding proteins of DNA repair vs. occupational and environmental exposure to lead, arsenic and pesticides].

    Science.gov (United States)

    Bukowski, Karol; Woźniak, Katarzyna

    2017-10-12

    Genetic polymorphism is associated with the occurrence of at least 2 different alleles in the locus with a frequency higher than 1% in the population. Among polymorphisms we can find single nucleotide polymorphism (SNP) and polymorphism of variable number of tandem repeats. The presence of certain polymorphisms in genes encoding DNA repair enzymes is associated with the speed and efficiency of DNA repair and can protect or expose humans to the effects provoked by xenobiotics. Chemicals, such as lead, arsenic pesticides are considered to exhibit strong toxicity. There are many different polymorphisms in genes encoding DNA repair enzymes, which determine the speed and efficiency of DNA damage repair induced by these xenobiotics. In the case of lead, the influence of various polymorphisms, such as APE1 (apurinic/apyrimidinic endonuclease 1) (rs1130409), hOGG1 (human 8-oxoguanine glycosylase) (rs1052133), XRCC1 (X-ray repair cross-complementing protein group 1) (rs25487), XRCC1 (rs1799782) and XRCC3 (X-ray repair cross-complementing protein group 3) (rs861539) were described. For arsenic polymorphisms, such as ERCC2 (excision repair cross-complementing) (rs13181), XRCC3 (rs861539), APE1 (rs1130409) and hOGG1 (rs1052133) were examined. As to pesticides, separate and combined effects of polymorphisms in genes encoding DNA repair enzymes, such as XRCC1 (rs1799782), hOGG1 (rs1052133), XRCC4 (X-ray repair cross-complementing protein group 4) (rs28360135) and the gene encoding the detoxification enzyme PON1 paraoxonase (rs662) were reported. Med Pr 2018;69(1). This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  2. Linking Genes to Microbial Biogeochemical Cycling: Lessons from Arsenic.

    Science.gov (United States)

    Zhu, Yong-Guan; Xue, Xi-Mei; Kappler, Andreas; Rosen, Barry P; Meharg, Andrew A

    2017-07-05

    The biotransformation of arsenic is highly relevant to the arsenic biogeochemical cycle. Identification of the molecular details of microbial pathways of arsenic biotransformation coupled with analyses of microbial communities by meta-omics can provide insights into detailed aspects of the complexities of this biocycle. Arsenic transformations couple to other biogeochemical cycles, and to the fate of both nutrients and other toxic environmental contaminants. Microbial redox metabolism of iron, carbon, sulfur, and nitrogen affects the redox and bioavailability of arsenic species. In this critical review we illustrate the biogeochemical processes and genes involved in arsenic biotransformations. We discuss how current and future metagenomic-, metatranscriptomic-, metaproteomic-, and metabolomic-based methods will help to decipher individual microbial arsenic transformation processes, and their connections to other biogeochemical cycle. These insights will allow future use of microbial metabolic capabilities for new biotechnological solutions to environmental problems. To understand the complex nature of inorganic and organic arsenic species and the fate of environmental arsenic will require integrating systematic approaches with biogeochemical modeling. Finally, from the lessons learned from these studies of arsenic biogeochemistry, we will be able to predict how the environment changes arsenic, and, in response, how arsenic biotransformations change the environment.

  3. Significantly increased risk of carotid atherosclerosis with arsenic exposure and polymorphisms in arsenic metabolism genes

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Yi-Chen [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, 250 Wusing St., Taipei 11031, Taiwan (China); Lien, Li-Ming [Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); School of Medicine, Taipei Medical University, Taipei, Taiwan (China); Department of Neurology, Shin Kong WHS Memorial Hospital, Taipei, Taiwan (China); Chung, Wen-Ting [Department of Neurology, Wanfang Hospital, Taipei Medical University, Taipei, Taiwan (China); Graduate Institute of Clinical Medicine, Taipei Medical University, Taipei, Taiwan (China); Hsieh, Fang-I; Hsieh, Pei-Fan [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, 250 Wusing St., Taipei 11031, Taiwan (China); Wu, Meei-Maan [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, 250 Wusing St., Taipei 11031, Taiwan (China); Graduate Institute of Basic Medicine, College of Medicine, Fu-Jen Catholic University, Taipei, Taiwan (China); Tseng, Hung-Pin [Department of Neurology, Lotung Poh-Ai Hospital, I-Lan, Taiwan (China); Chiou, Hung-Yi, E-mail: hychiou@tmu.edu.tw [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, 250 Wusing St., Taipei 11031, Taiwan (China); Chen, Chien-Jen [Genomics Research Center, Academia Sinica, Taipei, Taiwan (China)

    2011-08-15

    Individual susceptibility to arsenic-induced carotid atherosclerosis might be associated with genetic variations in arsenic metabolism. The purpose of this study is to explore the interaction effect on risk of carotid atherosclerosis between arsenic exposure and risk genotypes of purine nucleoside phosphorylase (PNP), arsenic (+3) methyltransferase (As3MT), and glutathione S-transferase omega 1 (GSTO1) and omega 2 (GSTO2). A community-based case-control study was conducted in northeastern Taiwan to investigate the arsenic metabolic-related genetic susceptibility to carotid atherosclerosis. In total, 863 subjects, who had been genotyped and for whom the severity of carotid atherosclerosis had been determined, were included in the present study. Individual well water was collected and arsenic concentration determined using hydride generation combined with flame atomic absorption spectrometry. The result showed that a significant dose-response trend (P=0.04) of carotid atherosclerosis risk associated with increasing arsenic concentration. Non-significant association between genetic polymorphisms of PNP Gly51Ser, Pro57Pro, As3MT Met287Thr, GSTO1 Ala140Asp, and GSTO2 A-183G and the risk for development of carotid atherosclerosis were observed. However, the significant interaction effect on carotid atherosclerosis risk was found for arsenic exposure (>50 {mu}g/l) and the haplotypes of PNP (p=0.0115). A marked elevated risk of carotid atherosclerosis was observed in subjects with arsenic exposure of >50 {mu}g/l in drinking water and those who carried the PNP A-T haplotype and at least either of the As3MT risk polymorphism or GSTO risk haplotypes (OR, 6.43; 95% CI, 1.79-23.19). In conclusion, arsenic metabolic genes, PNP, As3MT, and GSTO, may exacerbate the formation of atherosclerosis in individuals with high levels of arsenic concentration in well water (>50 {mu}g/l). - Highlights: {yields}Arsenic metabolic genes might be associated with carotid atherosclerosis. {yields

  4. Gene Therapy for Fracture Repair

    Science.gov (United States)

    2007-05-01

    forma - tion and finally remodeling [8]. Fracture callus formation eventually results in the bridging of the fracture and the restoration of skeletal...analysis was performed using ImaGene software (BioDiscovery, El Segundo, CA), that used an internal statistical analysis of the signal intensity of...expression during the normal repair of a simple femur fracture with the elimination of scar tissue from the healing bone. This model does not address

  5. Association of Environmental Arsenic Exposure, Genetic Polymorphisms of Susceptible Genes, and Skin Cancers in Taiwan

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    Ling-I Hsu

    2015-01-01

    Full Text Available Deficiency in the capability of xenobiotic detoxification and arsenic methylation may be correlated with individual susceptibility to arsenic-related skin cancers. We hypothesized that glutathione S-transferase (GST M1, T1, and P1, reactive oxygen species (ROS related metabolic genes (NQO1, EPHX1, and HO-1, and DNA repair genes (XRCC1, XPD, hOGG1, and ATM together may play a role in arsenic-induced skin carcinogenesis. We conducted a case-control study consisting of 70 pathologically confirmed skin cancer patients and 210 age and gender matched participants with genotyping of 12 selected polymorphisms. The skin cancer risks were estimated by odds ratio (OR and 95% confidence interval (CI using logistic regression. EPHX1 Tyr113His, XPD C156A, and GSTT1 null genotypes were associated with skin cancer risk (OR = 2.99, 95% CI = 1.01–8.83; OR = 2.04, 95% CI = 0.99–4.27; OR = 1.74, 95% CI = 1.00–3.02, resp.. However, none of these polymorphisms showed significant association after considering arsenic exposure status. Individuals carrying three risk polymorphisms of EPHX1 Tyr113His, XPD C156A, and GSTs presented a 400% increased skin cancer risk when compared to those with less than or equal to one polymorphism. In conclusion, GSTs, EPHX1, and XPD are potential genetic factors for arsenic-induced skin cancers. The roles of these genes for arsenic-induced skin carcinogenesis need to be further evaluated.

  6. Genes involved in arsenic transformation and resistance associated with different levels of arsenic-contaminated soils

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    Wang Gejiao

    2009-01-01

    Full Text Available Abstract Background Arsenic is known as a toxic metalloid, which primarily exists in inorganic form [As(III and As(V] and can be transformed by microbial redox processes in the natural environment. As(III is much more toxic and mobile than As(V, hence microbial arsenic redox transformation has a major impact on arsenic toxicity and mobility which can greatly influence the human health. Our main purpose was to investigate the distribution and diversity of microbial arsenite-resistant species in three different arsenic-contaminated soils, and further study the As(III resistance levels and related functional genes of these species. Results A total of 58 arsenite-resistant bacteria were identified from soils with three different arsenic-contaminated levels. Highly arsenite-resistant bacteria (MIC > 20 mM were only isolated from the highly arsenic-contaminated site and belonged to Acinetobacter, Agrobacterium, Arthrobacter, Comamonas, Rhodococcus, Stenotrophomonas and Pseudomonas. Five arsenite-oxidizing bacteria that belonged to Achromobacter, Agrobacterium and Pseudomonas were identified and displayed a higher average arsenite resistance level than the non-arsenite oxidizers. 5 aoxB genes encoding arsenite oxidase and 51 arsenite transporter genes [18 arsB, 12 ACR3(1 and 21 ACR3(2] were successfully amplified from these strains using PCR with degenerate primers. The aoxB genes were specific for the arsenite-oxidizing bacteria. Strains containing both an arsenite oxidase gene (aoxB and an arsenite transporter gene (ACR3 or arsB displayed a higher average arsenite resistance level than those possessing an arsenite transporter gene only. Horizontal transfer of ACR3(2 and arsB appeared to have occurred in strains that were primarily isolated from the highly arsenic-contaminated soil. Conclusion Soils with long-term arsenic contamination may result in the evolution of highly diverse arsenite-resistant bacteria and such diversity was probably caused in

  7. Reduced cellular DNA repair capacity after environmentally relevant arsenic exposure. Influence of Ogg1 deficiency

    Energy Technology Data Exchange (ETDEWEB)

    Bach, Jordi; Peremartí, Jana; Annangi, Balasubramnayam [Grup de Mutagènesi, Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona (Spain); Marcos, Ricard, E-mail: ricard.marcos@uab.es [Grup de Mutagènesi, Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona (Spain); CIBER Epidemiología y Salud Pública, ISCIII, Madrid (Spain); Hernández, Alba, E-mail: alba.hernandez@uab.es [Grup de Mutagènesi, Departament de Genètica i de Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona (Spain); CIBER Epidemiología y Salud Pública, ISCIII, Madrid (Spain)

    2015-09-15

    Highlights: • Repair ability under long-term exposure to arsenic was tested using the comet assay. • Effects were measured under Ogg1 wild-type and deficient backgrounds. • Exposed cells repair less efficiency the DNA damage induced by SA, KBrO{sub 3}, MMA{sup III} or UVC radiation. • Oxidative damage and Ogg1 deficient background exacerbate repair deficiencies. • Overexpression of the arsenic metabolizing enzyme As3mt acts as adaptive mechanism. - Abstract: Inorganic arsenic (i-As) is a genotoxic and carcinogenic environmental contaminant known to affect millions of people worldwide. Our previous work demonstrated that chronic sub-toxic i-As concentrations were able to induce biologically significant levels of genotoxic and oxidative DNA damage that were strongly influenced by the Ogg1 genotype. In order to study the nature of the observed levels of damage and the observed differences between MEF Ogg1{sup +/+} and Ogg1{sup −/−} genetic backgrounds, the genotoxic and oxidative DNA repair kinetics of 18-weeks exposed MEF cells were evaluated by the comet assay. Results indicate that MEF Ogg1{sup +/+} and Ogg1{sup −/−} cells chronically exposed to i-As repair the DNA damage induced by arsenite, potassium bromide and UVC radiation less efficiently than control cells, being that observation clearly more pronounced in MEF Ogg1{sup −/−} cells. Consequently, exposed cells accumulate a higher percentage of unrepaired DNA damage at the end of the repair period. As an attempt to eliminate i-As associated toxicity, chronically exposed MEF Ogg1{sup −/−} cells overexpress the arsenic metabolizing enzyme As3mt. This adaptive response confers cells a significant resistance to i-As-induced cell death, but at expenses of accumulating high levels of DNA damage due to their repair impairment. Overall, the work presented here evidences that i-As chronic exposure disrupts the normal cellular repair function, and that oxidative DNA damage—and Ogg1 deficiency

  8. Nicotinamide Enhances Repair of Arsenic and Ultraviolet Radiation-Induced DNA Damage in HaCaT Keratinocytes and Ex Vivo Human Skin

    OpenAIRE

    Thompson, Benjamin C.; Halliday, Gary M.; Damian, Diona L.

    2015-01-01

    Arsenic-induced skin cancer is a significant global health burden. In areas with arsenic contamination of water sources, such as China, Pakistan, Myanmar, Cambodia and especially Bangladesh and West Bengal, large populations are at risk of arsenic-induced skin cancer. Arsenic acts as a co-carcinogen with ultraviolet (UV) radiation and affects DNA damage and repair. Nicotinamide (vitamin B3) reduces premalignant keratoses in sun-damaged skin, likely by prevention of UV-induced cellular energy ...

  9. Distribution of microbial arsenic reduction, oxidation and extrusion genes along a wide range of environmental arsenic concentrations.

    Directory of Open Access Journals (Sweden)

    Lorena V Escudero

    Full Text Available The presence of the arsenic oxidation, reduction, and extrusion genes arsC, arrA, aioA, and acr3 was explored in a range of natural environments in northern Chile, with arsenic concentrations spanning six orders of magnitude. A combination of primers from the literature and newly designed primers were used to explore the presence of the arsC gene, coding for the reduction of As (V to As (III in one of the most common detoxification mechanisms. Enterobacterial related arsC genes appeared only in the environments with the lowest As concentration, while Firmicutes-like genes were present throughout the range of As concentrations. The arrA gene, involved in anaerobic respiration using As (V as electron acceptor, was found in all the systems studied. The As (III oxidation gene aioA and the As (III transport gene acr3 were tracked with two primer sets each and they were also found to be spread through the As concentration gradient. Sediment samples had a higher number of arsenic related genes than water samples. Considering the results of the bacterial community composition available for these samples, the higher microbial phylogenetic diversity of microbes inhabiting the sediments may explain the increased number of genetic resources found to cope with arsenic. Overall, the environmental distribution of arsenic related genes suggests that the occurrence of different ArsC families provides different degrees of protection against arsenic as previously described in laboratory strains, and that the glutaredoxin (Grx-linked arsenate reductases related to Enterobacteria do not confer enough arsenic resistance to live above certain levels of As concentrations.

  10. Chronic occupational exposure to arsenic induces carcinogenic gene signaling networks and neoplastic transformation in human lung epithelial cells

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    Stueckle, Todd A., E-mail: tstueckle@hsc.wvu.edu [Department of Basic Pharmaceutical Sciences, West Virginia University, Morgantown, WV 26506 (United States); Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Lu, Yongju, E-mail: yongju6@hotmail.com [Department of Basic Pharmaceutical Sciences, West Virginia University, Morgantown, WV 26506 (United States); Davis, Mary E., E-mail: mdavis@wvu.edu [Department of Physiology, West Virginia University, Morgantown, WV 26506 (United States); Wang, Liying, E-mail: lmw6@cdc.gov [Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505 (United States); Jiang, Bing-Hua, E-mail: bhjiang@jefferson.edu [Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107 (United States); Holaskova, Ida, E-mail: iholaskova@hsc.wvu.edu [Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV 26506 (United States); Schafer, Rosana, E-mail: rschafer@hsc.wvu.edu [Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV 26506 (United States); Barnett, John B., E-mail: jbarnett@hsc.wvu.edu [Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV 26506 (United States); Rojanasakul, Yon, E-mail: yrojan@hsc.wvu.edu [Department of Basic Pharmaceutical Sciences, West Virginia University, Morgantown, WV 26506 (United States)

    2012-06-01

    Chronic arsenic exposure remains a human health risk; however a clear mode of action to understand gene signaling-driven arsenic carcinogenesis is currently lacking. This study chronically exposed human lung epithelial BEAS-2B cells to low-dose arsenic trioxide to elucidate cancer promoting gene signaling networks associated with arsenic-transformed (B-As) cells. Following a 6 month exposure, exposed cells were assessed for enhanced cell proliferation, colony formation, invasion ability and in vivo tumor formation compared to control cell lines. Collected mRNA was subjected to whole genome expression microarray profiling followed by in silico Ingenuity Pathway Analysis (IPA) to identify lung carcinogenesis modes of action. B-As cells displayed significant increases in proliferation, colony formation and invasion ability compared to BEAS-2B cells. B-As injections into nude mice resulted in development of primary and secondary metastatic tumors. Arsenic exposure resulted in widespread up-regulation of genes associated with mitochondrial metabolism and increased reactive oxygen species protection suggesting mitochondrial dysfunction. Carcinogenic initiation via reactive oxygen species and epigenetic mechanisms was further supported by altered DNA repair, histone, and ROS-sensitive signaling. NF-κB, MAPK and NCOR1 signaling disrupted PPARα/δ-mediated lipid homeostasis. A ‘pro-cancer’ gene signaling network identified increased survival, proliferation, inflammation, metabolism, anti-apoptosis and mobility signaling. IPA-ranked signaling networks identified altered p21, EF1α, Akt, MAPK, and NF-κB signaling networks promoting genetic disorder, altered cell cycle, cancer and changes in nucleic acid and energy metabolism. In conclusion, transformed B-As cells with their whole genome expression profile provide an in vitro arsenic model for future lung cancer signaling research and data for chronic arsenic exposure risk assessment. Highlights: ► Chronic As{sub 2}O

  11. Nicotinamide enhances repair of arsenic and ultraviolet radiation-induced DNA damage in HaCaT keratinocytes and ex vivo human skin.

    Directory of Open Access Journals (Sweden)

    Benjamin C Thompson

    Full Text Available Arsenic-induced skin cancer is a significant global health burden. In areas with arsenic contamination of water sources, such as China, Pakistan, Myanmar, Cambodia and especially Bangladesh and West Bengal, large populations are at risk of arsenic-induced skin cancer. Arsenic acts as a co-carcinogen with ultraviolet (UV radiation and affects DNA damage and repair. Nicotinamide (vitamin B3 reduces premalignant keratoses in sun-damaged skin, likely by prevention of UV-induced cellular energy depletion and enhancement of DNA repair. We investigated whether nicotinamide modifies DNA repair following exposure to UV radiation and sodium arsenite. HaCaT keratinocytes and ex vivo human skin were exposed to 2μM sodium arsenite and low dose (2J/cm2 solar-simulated UV, with and without nicotinamide supplementation. DNA photolesions in the form of 8-oxo-7,8-dihydro-2'-deoxyguanosine and cyclobutane pyrimidine dimers were detected by immunofluorescence. Arsenic exposure significantly increased levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine in irradiated cells. Nicotinamide reduced both types of photolesions in HaCaT keratinocytes and in ex vivo human skin, likely by enhancing DNA repair. These results demonstrate a reduction of two different photolesions over time in two different models in UV and arsenic exposed cells. Nicotinamide is a nontoxic, inexpensive agent with potential for chemoprevention of arsenic induced skin cancer.

  12. Nicotinamide enhances repair of arsenic and ultraviolet radiation-induced DNA damage in HaCaT keratinocytes and ex vivo human skin.

    Science.gov (United States)

    Thompson, Benjamin C; Halliday, Gary M; Damian, Diona L

    2015-01-01

    Arsenic-induced skin cancer is a significant global health burden. In areas with arsenic contamination of water sources, such as China, Pakistan, Myanmar, Cambodia and especially Bangladesh and West Bengal, large populations are at risk of arsenic-induced skin cancer. Arsenic acts as a co-carcinogen with ultraviolet (UV) radiation and affects DNA damage and repair. Nicotinamide (vitamin B3) reduces premalignant keratoses in sun-damaged skin, likely by prevention of UV-induced cellular energy depletion and enhancement of DNA repair. We investigated whether nicotinamide modifies DNA repair following exposure to UV radiation and sodium arsenite. HaCaT keratinocytes and ex vivo human skin were exposed to 2μM sodium arsenite and low dose (2J/cm2) solar-simulated UV, with and without nicotinamide supplementation. DNA photolesions in the form of 8-oxo-7,8-dihydro-2'-deoxyguanosine and cyclobutane pyrimidine dimers were detected by immunofluorescence. Arsenic exposure significantly increased levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine in irradiated cells. Nicotinamide reduced both types of photolesions in HaCaT keratinocytes and in ex vivo human skin, likely by enhancing DNA repair. These results demonstrate a reduction of two different photolesions over time in two different models in UV and arsenic exposed cells. Nicotinamide is a nontoxic, inexpensive agent with potential for chemoprevention of arsenic induced skin cancer.

  13. Arsenic Resistance and Prevalence of Arsenic Resistance Genes in Campylobacter jejuni and Campylobacter coli Isolated from Retail Meats

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    Mohamed K. Fakhr

    2013-08-01

    Full Text Available Studies that investigate arsenic resistance in the foodborne bacterium Campylobacter are limited. A total of 552 Campylobacter isolates (281 Campylobacter jejuni and 271 Campylobacter coli isolated from retail meat samples were subjected to arsenic resistance profiling using the following arsenic compounds: arsanilic acid (4–2,048 μg/mL, roxarsone (4–2048 μg/mL, arsenate (16–8,192 μg/mL and arsenite (4–2,048 μg/mL. A total of 223 of these isolates (114 Campylobacter jejuni and 109 Campylobacter coli were further analyzed for the presence of five arsenic resistance genes (arsP, arsR, arsC, acr3, and arsB by PCR. Most of the 552 Campylobacter isolates were able to survive at higher concentrations of arsanilic acid (512–2,048 μg/mL, roxarsone (512–2,048 μg/mL, and arsenate (128–1,024 μg/mL, but at lower concentrations for arsenite (4–16 μg/mL. Ninety seven percent of the isolates tested by PCR showed the presence of arsP and arsR genes. While 95% of the Campylobacter coli isolates contained a larger arsenic resistance operon that has all of the four genes (arsP, arsR, arsC and acr3, 85% of the Campylobacter jejuni isolates carried the short operon (arsP, and arsR. The presence of arsC and acr3 did not significantly increase arsenic resistance with the exception of conferring resistance to higher concentrations of arsenate to some Campylobacter isolates. arsB was prevalent in 98% of the tested Campylobacter jejuni isolates, regardless of the presence or absence of arsC and acr3, but was completely absent in Campylobacter coli. To our knowledge, this is the first study to determine arsenic resistance and the prevalence of arsenic resistance genes in such a large number of Campylobacter isolates.

  14. Relation of polymorphism of arsenic metabolism genes to arsenic methylation capacity and developmental delay in preschool children in Taiwan.

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    Hsieh, Ru-Lan; Su, Chien-Tien; Shiue, Horng-Sheng; Chen, Wei-Jen; Huang, Shiau-Rung; Lin, Ying-Chin; Lin, Ming-I; Mu, Shu-Chi; Chen, Ray-Jade; Hsueh, Yu-Mei

    2017-04-15

    Inefficient arsenic methylation capacity has been associated with developmental delay in children. The present study was designed to explore whether polymorphisms and haplotypes of arsenic methyltransferase (AS3MT), glutathione-S-transferase omegas (GSTOs), and purine nucleoside phosphorylase (PNP) affect arsenic methylation capacity and developmental delay. A case-control study was conducted from August 2010 to March 2014. All participants were recruited from the Shin Kong Wu Ho-Su Memorial Teaching Hospital. In total, 179 children with developmental delay and 88 children without delay were recruited. Urinary arsenic species, including arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMAV), and dimethylarsinic acid (DMAV) were measured using a high-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. The polymorphisms of AS3MT, GSTO, and PNP were performed using the Sequenom MassARRAY platform with iPLEX Gold chemistry. Polymorphisms of AS3MT genes were found to affect susceptibility to developmental delay in children, but GSTO and PNP polymorphisms were not. Participants with AS3MT rs3740392 A/G+G/G genotype, compared with AS3MT rs3740392 A/A genotype, had a significantly lower secondary methylation index. This may result in an increased OR for developmental delay. Participants with the AS3MT high-risk haplotype had a significantly higher OR than those with AS3MT low-risk haplotypes [OR and 95% CI, 1.59 (1.08-2.34)]. This is the first study to show a joint dose-response effect of this AS3MT high-risk haplotype and inefficient arsenic methylation capacity on developmental delay. Our data provide evidence that AS3MT genes are related to developmental delay and may partially influence arsenic methylation capacity. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Polymorphisms in human DNA repair genes and head and neck ...

    Indian Academy of Sciences (India)

    Genetic polymorphisms in some DNA repair proteins are associated with a number of malignant transformations like head and neck squamous cell carcinoma (HNSCC). Xeroderma pigmentosum group D (XPD) and X-ray repair cross-complementing proteins 1 (XRCC1) and 3 (XRCC3) genes are involved in DNA repair ...

  16. Arsenic exposure from drinking water is associated with decreased gene expression and increased DNA methylation in peripheral blood.

    Science.gov (United States)

    Ameer, Syeda Shegufta; Engström, Karin; Hossain, Mohammad Bakhtiar; Concha, Gabriela; Vahter, Marie; Broberg, Karin

    2017-04-15

    Exposure to inorganic arsenic increases the risk of cancer and non-malignant diseases. Inefficient arsenic metabolism is a marker for susceptibility to arsenic toxicity. Arsenic may alter gene expression, possibly by altering DNA methylation. To elucidate the associations between arsenic exposure, gene expression, and DNA methylation in peripheral blood, and the modifying effects of arsenic metabolism. The study participants, women from the Andes, Argentina, were exposed to arsenic via drinking water. Arsenic exposure was assessed as the sum of arsenic metabolites in urine (U-As), using high performance liquid-chromatography hydride-generation inductively-coupled-plasma-mass-spectrometry, and arsenic metabolism efficiency was assessed by the urinary fractions (%) of the individual metabolites. Genome-wide gene expression (N=80 women) and DNA methylation (N=93; 80 overlapping with gene expression) in peripheral blood were measured using Illumina DirectHyb HumanHT-12 v4.0 and Infinium Human-Methylation 450K BeadChip, respectively. U-As concentrations, ranging 10-1251μg/L, was associated with decreased gene expression: 64% of the top 1000 differentially expressed genes were down-regulated with increasing U-As. U-As was also associated with hypermethylation: 87% of the top 1000CpGs were hypermethylated with increasing U-As. The expression of six genes and six individual CpG sites were significantly associated with increased U-As concentration. Pathway analyses revealed enrichment of genes related to cell death and cancer. The pathways differed somewhat depending on arsenic metabolism efficiency. We found no overlap between arsenic-related gene expression and DNA methylation for individual genes. Increased arsenic exposure was associated with lower gene expression and hypermethylation in peripheral blood, but with no evident overlap. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Recurrent horizontal transfer of arsenite methyltransferase genes facilitated adaptation of life to arsenic.

    Science.gov (United States)

    Chen, Song-Can; Sun, Guo-Xin; Rosen, Barry P; Zhang, Si-Yu; Deng, Ye; Zhu, Bo-Kai; Rensing, Christopher; Zhu, Yong-Guan

    2017-08-10

    The toxic metalloid arsenic has been environmentally ubiquitous since life first arose nearly four billion years ago and presents a challenge for the survival of all living organisms. Its bioavailability has varied dramatically over the history of life on Earth. As life spread, biogeochemical and climate changes cyclically increased and decreased bioavailable arsenic. To elucidate the history of arsenic adaptation across the tree of life, we reconstructed the phylogeny of the arsM gene that encodes the As(III) S-adenosylmethionine (SAM) methyltransferase. Our results suggest that life successfully moved into arsenic-rich environments in the late Archean Eon and Proterozoic Eon, respectively, by the spread of arsM genes. The arsM genes of bacterial origin have been transferred to other kingdoms of life on at least six occasions, and the resulting domesticated arsM genes promoted adaptation to environmental arsenic. These results allow us to peer into the history of arsenic adaptation of life on our planet and imply that dissemination of genes encoding diverse adaptive functions to toxic chemicals permit adaptation to changes in concentrations of environmental toxins over evolutionary history.

  18. Isolating human DNA repair genes using rodent-cell mutants

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, L.H.; Weber, C.A.; Brookman, K.W.; Salazar, E.P.; Stewart, S.A.; Mitchell, D.L.

    1987-03-23

    The DNA repair systems of rodent and human cells appear to be at least as complex genetically as those in lower eukaryotes and bacteria. The use of mutant lines of rodent cells as a means of identifying human repair genes by functional complementation offers a new approach toward studying the role of repair in mutagenesis and carcinogenesis. In each of six cases examined using hybrid cells, specific human chromosomes have been identified that correct CHO cell mutations affecting repair of damage from uv or ionizing radiations. This finding suggests that both the repair genes and proteins may be virtually interchangeable between rodent and human cells. Using cosmid vectors, human repair genes that map to chromosome 19 have cloned as functional sequences: ERCC2 and XRCC1. ERCC1 was found to have homology with the yeast excision repair gene RAD10. Transformants of repair-deficient cell lines carrying the corresponding human gene show efficient correction of repair capacity by all criteria examined. 39 refs., 1 fig., 1 tab.

  19. Oxidative DNA damage and repair in children exposed to low levels of arsenic in utero and during early childhood: Application of salivary and urinary biomarkers

    Energy Technology Data Exchange (ETDEWEB)

    Hinhumpatch, Pantip; Navasumrit, Panida [Laboratory of Environmental Toxicology, Chulabhorn Research Institute, Laksi, Bangkok (Thailand); Chulabhorn Graduate Institute, Laksi, Bangkok (Thailand); Center of Excellence on Environmental Health and Toxicology, CHE, Ministry of Education (Thailand); Chaisatra, Krittinee; Promvijit, Jeerawan [Laboratory of Environmental Toxicology, Chulabhorn Research Institute, Laksi, Bangkok (Thailand); Mahidol, Chulabhorn [Laboratory of Chemical Carcinogenesis, Chulabhorn Research Institute, Laksi, Bangkok (Thailand); Ruchirawat, Mathuros, E-mail: mathuros@cri.or.th [Laboratory of Environmental Toxicology, Chulabhorn Research Institute, Laksi, Bangkok (Thailand); Chulabhorn Graduate Institute, Laksi, Bangkok (Thailand); Center of Excellence on Environmental Health and Toxicology, CHE, Ministry of Education (Thailand); Department of Pharmacology, Faculty of Science, Mahidol University, Phayathai, Bangkok (Thailand)

    2013-12-15

    The present study aimed to assess arsenic exposure and its effect on oxidative DNA damage and repair in young children exposed in utero and continued to live in arsenic-contaminated areas. To address the need for biological specimens that can be acquired with minimal discomfort to children, we used non-invasive urinary and salivary-based assays for assessing arsenic exposure and early biological effects that have potentially serious health implications. Levels of arsenic in nails showed the greatest magnitude of difference between exposed and control groups, followed by arsenic concentrations in saliva and urine. Arsenic levels in saliva showed significant positive correlations with other biomarkers of arsenic exposure, including arsenic accumulation in nails (r = 0.56, P < 0.001) and arsenic concentration in urine (r = 0.50, P < 0.05). Exposed children had a significant reduction in arsenic methylation capacity indicated by decreased primary methylation index and secondary methylation index in both urine and saliva samples. Levels of salivary 8-OHdG in exposed children were significantly higher (∼ 4-fold, P < 0.01), whereas levels of urinary 8-OHdG excretion and salivary hOGG1 expression were significantly lower in exposed children (∼ 3-fold, P < 0.05), suggesting a defect in hOGG1 that resulted in ineffective cleavage of 8-OHdG. Multiple regression analysis results showed that levels of inorganic arsenic (iAs) in saliva and urine had a significant positive association with salivary 8-OHdG and a significant negative association with salivary hOGG1 expression. - Highlights: • The effects of arsenic exposure in utero and through early childhood were studied. • Arsenic-exposed children had a reduction in arsenic methylation capacity. • Exposed children had more DNA damage, observed as elevated salivary 8-OHdG. • Lower salivary hOGG1 in exposed children indicated impairment of 8-OHdG repair. • Salivary and urinary 8-OHdG levels were discordant.

  20. DNA methylation of extracellular matrix remodeling genes in children exposed to arsenic.

    Science.gov (United States)

    Gonzalez-Cortes, Tania; Recio-Vega, Rogelio; Lantz, Robert Clark; Chau, Binh T

    2017-08-15

    Several novel mechanistic findings regarding to arsenic's pathogenesis has been reported and some of them suggest that the etiology of some arsenic induced diseases are due in part to heritable changes to the genome via epigenetic processes such as DNA methylation, histone maintenance, and mRNA expression. Recently, we reported that arsenic exposure during in utero and early life was associated with impairment in the lung function and abnormal receptor for advanced glycation endproducts (RAGE), matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) sputum levels. Based on our results and the reported arsenic impacts on DNA methylation, we designed this study in our cohort of children exposed in utero and early childhood to arsenic with the aim to associate DNA methylation of MMP9, TIMP1 and RAGE genes with its protein sputum levels and with urinary and toenail arsenic levels. The results disclosed hypermethylation in MMP9 promotor region in the most exposed children; and an increase in the RAGE sputum levels among children with the mid methylation level; there were also positive associations between MMP9 DNA methylation with arsenic toenail concentrations; RAGE DNA methylation with iAs, and %DMA; and finally between TIMP1 DNA methylation with the first arsenic methylation. A negative correlation between MMP9 sputum levels with its DNA methylation was registered. In conclusion, arsenic levels were positive associated with the DNA methylation of extracellular matrix remodeling genes;, which in turn could modifies the biological process in which they are involved causing or predisposing to lung diseases. Copyright © 2017. Published by Elsevier Inc.

  1. DNA Repair in Drosophila: Mutagens, Models, and Missing Genes.

    Science.gov (United States)

    Sekelsky, Jeff

    2017-02-01

    The numerous processes that damage DNA are counterbalanced by a complex network of repair pathways that, collectively, can mend diverse types of damage. Insights into these pathways have come from studies in many different organisms, including Drosophila melanogaster Indeed, the first ideas about chromosome and gene repair grew out of Drosophila research on the properties of mutations produced by ionizing radiation and mustard gas. Numerous methods have been developed to take advantage of Drosophila genetic tools to elucidate repair processes in whole animals, organs, tissues, and cells. These studies have led to the discovery of key DNA repair pathways, including synthesis-dependent strand annealing, and DNA polymerase theta-mediated end joining. Drosophila appear to utilize other major repair pathways as well, such as base excision repair, nucleotide excision repair, mismatch repair, and interstrand crosslink repair. In a surprising number of cases, however, DNA repair genes whose products play important roles in these pathways in other organisms are missing from the Drosophila genome, raising interesting questions for continued investigations. Copyright © 2017 by the Genetics Society of America.

  2. Arsenic exposure alters expression of cell cycle and lipid metabolism genes in the liver of adult zebrafish (Danio rerio).

    Science.gov (United States)

    Carlson, Patrick; Van Beneden, Rebecca J

    2014-08-01

    Adult zebrafish (Danio rerio) were used to investigate mRNA expression in the liver following 7-day and 21-day exposures to 0, 10, 50, or 500 ppb sodium arsenite. Arsenic exposure has been linked to several human disorders including cancers and cardiovascular and metabolic diseases. Quantitative PCR was employed to determine the mRNA expression of genes involved in cell cycle regulation [cyclin E1 (ccne1), WEE1 A kinase (wee1)], DNA damage repair [breast cancer 2 (brca2)] and lipid transport and metabolism [carnitine O-octanoyltransferase (crot), fatty acid binding protein-3 (fabp3) and 3-hydroxy-3-methylglutaryl-CoA synthase 1 (hmgcs1)]. Results from the 7-day exposure showed sex- and dose-specific changes in expression of wee1, brca2, crot and hmgcs1. No significant differences from controls were observed in fish exposed for 21 days. Expression of all genes, except ccne1, was significantly different between the 7- and 21-day exposures. The results presented here correlate with prior findings from our lab and others, and offer further insight into potential mechanisms of low-dose arsenic exposure. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. The behavior of antibiotic resistance genes and arsenic influenced by biochar during different manure composting.

    Science.gov (United States)

    Cui, Erping; Wu, Ying; Jiao, Yanan; Zuo, Yiru; Rensing, Christopher; Chen, Hong

    2017-06-01

    The effect of two different biochar types, rice straw biochar (RSB) and mushroom biochar (MB), on chicken manure composting was previously examined by monitoring the fate of antibiotic resistance genes (ARGs) and arsenic. The behavior of ARGs and arsenic in other kinds of manure composting with the same biochar types had not been examined. In this study, we added either RSB or MB to pig and duck manure composts to study the behavior of ARGs (tet genes, sul genes, and chloramphenicol resistance genes) and arsenic under the same experimental condition. The results showed that the average removal values of selected ARGs were respectively 2.56 and 2.09 log units in duck and pig manure compost without the addition of biochar. The effect of biochar addition on the average removal value of ARGs depended on the type of biochar and manure. For instance, in pig manure compost, MB addition increased the average removal value of ARGs, while RSB addition decreased. And both biochar additions had a negative influence on the average removal value of ARGs in duck manure compost. Analytical results also demonstrated that MB addition reduced total arsenic and the percentage of bioavailable arsenic more than RSB.

  4. Pathological assessment of mismatch repair gene variants in Lynch syndrome

    DEFF Research Database (Denmark)

    Rasmussen, Lene Juel; Heinen, Christopher D; Royer-Pokora, Brigitte

    2012-01-01

    Lynch syndrome (LS) is caused by germline mutations in DNA mismatch repair (MMR) genes and is the most prevalent hereditary colorectal cancer syndrome. A significant proportion of variants identified in MMR and other common cancer susceptibility genes are missense or noncoding changes whose conse...

  5. Transcriptional Activity of Arsenic-Reducing Bacteria and Genes Regulated by Lactate and Biochar during Arsenic Transformation in Flooded Paddy Soil.

    Science.gov (United States)

    Qiao, Jiang-Tao; Li, Xiao-Min; Hu, Min; Li, Fang-Bai; Young, Lily Y; Sun, Wei-Min; Huang, Weilin; Cui, Jiang-Hu

    2017-12-15

    Organic substrates and biochar are important in controlling arsenic release from sediments and soils; however, little is known about their impact on arsenic-reducing bacteria and genes during arsenic transformation in flooded paddy soils. In this study, microcosm experiments were established to profile transcriptional activity of As(V)-respiring gene (arrA) and arsenic resistance gene (arsC) as well as the associated bacteria regulated by lactate and/or biochar in anaerobic arsenic-contaminated paddy soils. Chemical analyses revealed that lactate as the organic substrate stimulated microbial reduction of As(V) and Fe(III), which was simultaneously promoted by lactate+biochar, due to biochar's electron shuttle function that facilitates electron transfer from bacteria to As(V)/Fe(III). Sequencing and phylogenetic analyses demonstrated that both arrA closely associated with Geobacter (>60%, number of identical sequences/number of the total sequences) and arsC related to Enterobacteriaceae (>99%) were selected by lactate and lactate+biochar. Compared with the lactate microcosms, transcriptions of the bacterial 16S rRNA gene, Geobacter spp., and Geobacter arrA and arsC genes were increased in the lactate+biochar microcosms, where transcript abundances of Geobacter and Geobacter arrA closely tracked with dissolved As(V) concentrations. Our findings indicated that lactate and biochar in flooded paddy soils can stimulate the active As(V)-respiring bacteria Geobacter species for arsenic reduction and release, which probably increases arsenic bioavailability to rice plants.

  6. AS3MT-mediated tolerance to arsenic evolved by multiple independent horizontal gene transfers from bacteria to eukaryotes

    DEFF Research Database (Denmark)

    Palmgren, Michael Broberg; Engström, Karin; Hallström, Björn M

    2017-01-01

    the evolutionary origin of AS3MT and assessed the ability of different genotypes to produce methylated arsenic metabolites. Phylogenetic analysis suggests that multiple, independent horizontal gene transfers between different bacteria, and from bacteria to eukaryotes, increased tolerance to environmental arsenic...

  7. Mthfr gene ablation enhances susceptibility to arsenic prenatal toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Wlodarczyk, Bogdan J., E-mail: bwlodarczyk@austin.utexas.edu; Zhu, Huiping; Finnell, Richard H.

    2014-02-15

    Background: In utero exposure to arsenic is known to adversely affect reproductive outcomes. Evidence of arsenic teratogenicity varies widely and depends on individual genotypic differences in sensitivity to As. In this study, we investigated the potential interaction between 5,10-methylenetetrahydrofolate reductase (Mthfr) genotype and arsenic embryotoxicity using the Mthfr knockout mouse model. Methods: Pregnant dams were treated with sodium arsenate, and reproductive outcomes including: implantation, resorption, congenital malformation and fetal birth weight were recorded at E18.5. Results: When the dams in Mthfr{sup +/−} × Mthfr{sup +/−} matings were treated with 7.2 mg/kg As, the resorption rate increased to 43.4%, from a background frequency of 7.2%. The As treatment also induced external malformations (40.9%) and significantly lowered the average fetal birth weight among fetuses, without any obvious toxic effect on the dam. When comparing the pregnancy outcomes resulting from different mating scenarios (Mthfr{sup +/+} × Mthfr{sup +/−}, Mthfr{sup +/−} × Mthfr{sup +/−} and Mthfr{sup −/−} × {sup Mthfr+/−}) and arsenic exposure; the resorption rate showed a linear relationship with the number of null alleles (0, 1 or 2) in the Mthfr dams. Fetuses from nullizygous dams had the highest rate of external malformations (43%) and lowest average birth weight. When comparing the outcomes of reciprocal matings (nullizygote × wild-type versus wild-type × nullizygote) after As treatment, the null dams showed significantly higher rates of resorptions and malformations, along with lower fetal birth weights. Conclusions: Maternal genotype contributes to the sensitivity of As embryotoxicity in the Mthfr mouse model. The fetal genotype, however, does not appear to affect the reproductive outcome after in utero As exposure. - Highlights: • An interaction between Mthfr genotype and arsenic embryotoxicity is presented. • Maternal Mthfr genotype

  8. Expression profiling of Crambe abyssinica under arsenate stress identifies genes and gene networks involved in arsenic metabolism and detoxification

    Directory of Open Access Journals (Sweden)

    Kandasamy Suganthi

    2010-06-01

    Full Text Available Abstract Background Arsenic contamination is widespread throughout the world and this toxic metalloid is known to cause cancers of organs such as liver, kidney, skin, and lung in human. In spite of a recent surge in arsenic related studies, we are still far from a comprehensive understanding of arsenic uptake, detoxification, and sequestration in plants. Crambe abyssinica, commonly known as 'abyssinian mustard', is a non-food, high biomass oil seed crop that is naturally tolerant to heavy metals. Moreover, it accumulates significantly higher levels of arsenic as compared to other species of the Brassicaceae family. Thus, C. abyssinica has great potential to be utilized as an ideal inedible crop for phytoremediation of heavy metals and metalloids. However, the mechanism of arsenic metabolism in higher plants, including C. abyssinica, remains elusive. Results To identify the differentially expressed transcripts and the pathways involved in arsenic metabolism and detoxification, C. abyssinica plants were subjected to arsenate stress and a PCR-Select Suppression Subtraction Hybridization (SSH approach was employed. A total of 105 differentially expressed subtracted cDNAs were sequenced which were found to represent 38 genes. Those genes encode proteins functioning as antioxidants, metal transporters, reductases, enzymes involved in the protein degradation pathway, and several novel uncharacterized proteins. The transcripts corresponding to the subtracted cDNAs showed strong upregulation by arsenate stress as confirmed by the semi-quantitative RT-PCR. Conclusions Our study revealed novel insights into the plant defense mechanisms and the regulation of genes and gene networks in response to arsenate toxicity. The differential expression of transcripts encoding glutathione-S-transferases, antioxidants, sulfur metabolism, heat-shock proteins, metal transporters, and enzymes in the ubiquitination pathway of protein degradation as well as several unknown

  9. Mismatch repair genes in Lynch syndrome: a review

    OpenAIRE

    Silva,Felipe Cavalcanti Carneiro da; Valentin, Mev Dominguez; Ferreira, Fábio de Oliveira; Carraro, Dirce Maria; Rossi, Benedito Mauro

    2009-01-01

    Lynch syndrome represents 1-7% of all cases of colorectal cancer and is an autosomal-dominant inherited cancer predisposition syndrome caused by germline mutations in deoxyribonucleic acid (DNA) mismatch repair genes. Since the discovery of the major human genes with DNA mismatch repair function, mutations in five of them have been correlated with susceptibility to Lynch syndrome: mutS homolog 2 (MSH2); mutL homolog 1 (MLH1); mutS homolog 6 (MSH6); postmeiotic segregation increased 2 (PMS2); ...

  10. Aberrant DNA methylation and gene expression in livers of newborn mice transplacentally exposed to a hepatocarcinogenic dose of inorganic arsenic

    Science.gov (United States)

    Xie, Yaxiong; Liu, Jie; Benbrahim-Tallaa, Lamia; Ward, Jerry M.; Logsdon, Daniel; Diwan, Bhalchandra A.; Waalkes, Michael P.

    2008-01-01

    Our prior work showed that brief exposure of pregnant C3H mice to inorganic arsenic-induced hepatocellular carcinoma (HCC) formation in adult male offspring. The current study examined the early hepatic events associated with this oncogenic transformation. Pregnant mice were exposed to a known carcinogenic dose of arsenic (85 ppm) in the drinking water from gestation days 8 to 18. The dams were allowed to give birth and liver samples from newborn males were analyzed for arsenic content, global DNA methylation and aberrant expression of genes relevant to the carcinogenic process. Arsenic content in newborn liver reached 57 ng/g wet weight, indicating arsenic had crossed the placenta, reached the fetal liver and that significant amounts remained after birth. Global methylation status of hepatic DNA was not altered by arsenic in the newborn. However, a significant reduction in methylation occurred globally in GC-rich regions. Microarray and real-time RT-PCR analysis showed that arsenic exposure enhanced expression of genes encoding for glutathione production and caused aberrant expression of genes related to insulin growth factor signaling pathways and cytochrome P450 enzymes. Other expression alterations observed in the arsenic-treated male mouse newborn liver included the overexpression of cdk-inhibitors and stress response genes including increased expression of metallothionein-1 and decreased expression of betaine-homocysteine methyltransferase and thioether S-methyltransferase. Thus, transplacental exposure to arsenic at a hepatocarcinogenic dose induces alterations in DNA methylation and a complex set of aberrant gene expressions in the newborn liver, a target of arsenic carcinogenesis. PMID:17451858

  11. ATP-dependent arsenical pumps, gene products of the arsenical resistance operon of R-factor R773

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.M.; San Francisco, M.J.D.; Weigel, U.; Rosen, B.P.

    1986-05-01

    Plasmid-encoded resistance to antibiotics and heavy metals is frequently through synthesis of new transport systems for extrusion of the toxic compound. The inducible arsenical resistance (ars) operon of the conjugative R-factor R773 encodes two transport systems: one for arsenate and one for arsenite. In vivo studies of the energetics of arsenical extrusion have suggested that ATP is the driving force and that a PNF is neither necessary nor sufficient. The 4.3 Kb HindIII fragment containing the ars operon was cloned into M13 mWB2348 in both orientations, a series of ordered deletions were created using Ba131 digestion, and the sequence of the operon determined. Four open reading frames, arsA, B, C, and D, were found. From genetic evidence, the ArsA and B proteins comprise the arsenite pump, while the ArsC and D proteins are involved in arsenate pumping. The arsA ORF encodes a soluble protein of 63,167 Da with two potential adenylate binding sites. The ArsA protein was purified from the cytosol and shown to bind ATP. The arsB ORF encodes a membrane protein of 31,197 Da. The arsC ORF encodes a membrane protein of 17,311 Da. Mini-Nu phage transposition was used to create gene fusions between the arsC gene and lacZ. By immunoprecipitation and immunoblots using anti-..beta..-galactosidase serum, this strain was shown to produce a 133 kDa hybrid protein localized in inner membrane and not found in the cytosol. The arsD ORF encodes a 15,811 Da soluble protein. The ArsD protein has been purified from the cytosol. In summary, the data suggest that the ars operon produces a single transcript for the synthesis of two resistances and two anion pumps.

  12. DNA damage and decreased DNA repair in peripheral blood mononuclear cells in individuals exposed to arsenic and lead in a mining site.

    Science.gov (United States)

    Jasso-Pineda, Yolanda; Díaz-Barriga, Fernando; Calderón, Jaqueline; Yáñez, Leticia; Carrizales, Leticia; Pérez-Maldonado, Iván N

    2012-05-01

    The aim of this study was to evaluate DNA damage and the capacity for DNA repair in children exposed to arsenic and lead. During 2006, we studied a total of 85 healthy children (aged 4-11 years) who were residents of Villa de la Paz (community A), Matehuala (community B), and Soledad de Graciano Sanchez (community C) in San Luis Potosi, Mexico. The quantification of arsenic in urine (AsU) and lead in blood (PbB) was performed by atomic absorption spectrophotometry. The alkaline comet assay was used to evaluate DNA damage and DNA repair. The highest levels of AsU and PbB in children were found in community A (44.5 μg/g creatinine for arsenic and 11.4 μg/dL for lead), followed by community B (16.8 μg/g creatinine for arsenic and 7.3 μg/dL for lead) and finally by children living in community C (12.8 μg/g creatinine for arsenic and 5.3 μg/dL for lead). When DNA damage was assessed, children living in community A had the highest DNA damage. Analysis of these same cells 1 h after a challenge with H(2)O(2) 10 μM showed a dramatic increase in DNA damage in the cells of children living in community B and community C, but not in the cells of children living in community A. Moreover, significantly higher levels of DNA damage were observed 3 h after the challenge ended (repair period) in cells from individuals living in community A. Our results show that children exposed to metals might be more susceptible to DNA alterations.

  13. Arsenic-Induced Genotoxicity and Genetic Susceptibility to Arsenic-Related Pathologies

    Science.gov (United States)

    Faita, Francesca; Cori, Liliana; Bianchi, Fabrizio; Andreassi, Maria Grazia

    2013-01-01

    The arsenic (As) exposure represents an important problem in many parts of the World. Indeed, it is estimated that over 100 million individuals are exposed to arsenic, mainly through a contamination of groundwaters. Chronic exposure to As is associated with adverse effects on human health such as cancers, cardiovascular diseases, neurological diseases and the rate of morbidity and mortality in populations exposed is alarming. The purpose of this review is to summarize the genotoxic effects of As in the cells as well as to discuss the importance of signaling and repair of arsenic-induced DNA damage. The current knowledge of specific polymorphisms in candidate genes that confer susceptibility to arsenic exposure is also reviewed. We also discuss the perspectives offered by the determination of biological markers of early effect on health, incorporating genetic polymorphisms, with biomarkers for exposure to better evaluate exposure-response clinical relationships as well as to develop novel preventative strategies for arsenic- health effects. PMID:23583964

  14. Polymorphisms in human DNA repair genes and head and neck ...

    Indian Academy of Sciences (India)

    Sci. USA 97, 9886–9891. Viswanathan H. and Wilson J. A. 2004 Alcohol—the neglected factor in head and neck cancer. Clin. Otolaryngol. 29, 295–300. Vogel U., Hedayati M., Dybdahl M., Grossman L. and Nexo B. A.. 2001 Polymorphisms of the DNA repair gene XPD, correlations with risk of basal cell carcinoma revisited.

  15. Dynamic regulation of cerebral DNA repair genes by psychological stress

    DEFF Research Database (Denmark)

    Forsberg, Kristin; Aalling, Nadia; Wörtwein, Gitta

    2015-01-01

    was seen in HC, but with overall smaller effects and without the induction after acute stress. Nuclear DNA damage from oxidation as measured by the comet assay was unaffected by stress in both regions. We conclude that psychological stress have a dynamic influence on brain DNA repair gene expression...

  16. Molecular cloning of the human excision repair gene ERCC-6.

    NARCIS (Netherlands)

    C. Troelstra (Christine); H. Odijk (Hanny); J. de Wit (Jan); A. Westerveld (Andries); L.H. Thompson; D. Bootsma (Dirk); J.H.J. Hoeijmakers (Jan)

    1990-01-01

    textabstractThe UV-sensitive, nucleotide excision repair-deficient Chinese hamster mutant cell line UV61 was used to identify and clone a correcting human gene, ERCC-6. UV61, belonging to rodent complementation group 6, is only moderately UV sensitive in comparison with mutant lines in groups 1 to

  17. Review: Clinical aspects of hereditary DNA Mismatch repair gene mutations

    NARCIS (Netherlands)

    Sijmons, Rolf H.; Hofstra, Robert M. W.

    Inherited mutations of the DNA Mismatch repair genes MLH1, MSH2, MSH6 and PMS2 can result in two hereditary tumor syndromes: the adult-onset autosomal dominant Lynch syndrome, previously referred to as Hereditary Non-Polyposis Colorectal Cancer (HNPCC) and the childhood-onset autosomal recessive

  18. A genomic island harboring arsenic resistance genes varies in gene content and is located in different chromosomal loci among Listeria monocytogenes strains

    Science.gov (United States)

    In the foodborne pathogen Listeria monocytogenes, arsenic resistance has been often encountered among certain clonal groups of serotype 4b and was earlier found to be strongly associated with an arsenic resistance gene cluster within a 35 kb chromosomal region, designated Listeria genomic island 2 (...

  19. Evaluation of a GFP Report Gene Construct for Environmental Arsenic Detection

    Energy Technology Data Exchange (ETDEWEB)

    Roberto, F.F.; Barnes, J.M.; Bruhn, D.F.

    2002-03-28

    Detection of arsenic and other heavy metal contaminants in the environment is critical to ensuring safe drinking water and effective cleanup of historic activities that have led to widespread contamination of soil and groundwater. Biosensors have the potential to significantly reduce the costs associated with site characterization and long term environmental monitoring. By exploiting the highly selective and sensitive natural mechanisms by which bacteria and other living organisms respond to heavy metals, and fusing transcriptionally active components of these mechanisms to reporter genes, such as B-galactosidase, bacterial luciferase (lux), or green fluorescent protein (GFP) from marine jellyfish, it is possible to produce inexpensive, yet effective biosensors. This article describes the response to submicrogram quantities of arsenite and arsenate of a whole cell arsenic biosensor utilizing a GFP reporter gene.

  20. METHYLATED TRIVALENT ARSENICALS AS CANDIDATE ULTIMATE GENOTOXIC FORMS OF ARSENIC: INDUCTION OF CHROMOSOMAL MUTATIONS BUT NOT GENE MUTATIONS

    Science.gov (United States)

    ABSTRACT Arsenic is a prevalent human carcinogen whose mutagenicity has not been characterized fully. Exposure to either form of inorganic arsenic, AsIII or AsV, can result in the formation of at least four organic metabolites: monomethylarsonic acid, monomethylarsonous aci...

  1. Germline Mutations in DNA Repair Genes in Lung Adenocarcinoma.

    Science.gov (United States)

    Parry, Erin M; Gable, Dustin L; Stanley, Susan E; Khalil, Sara E; Antonescu, Valentin; Florea, Liliana; Armanios, Mary

    2017-11-01

    Although lung cancer is generally thought to be environmentally provoked, anecdotal familial clustering has been reported, suggesting that there may be genetic susceptibility factors. We systematically tested whether germline mutations in eight candidate genes may be risk factors for lung adenocarcinoma. We studied lung adenocarcinoma cases for which germline sequence data had been generated as part of The Cancer Genome Atlas project but had not been previously analyzed. We selected eight genes, ATM serine/threonine kinase gene (ATM), BRCA2, DNA repair associated gene (BRCA2), checkpoint kinase 2 gene (CHEK2), EGFR, parkin RBR E3 ubiquitin protein ligase gene (PARK2), telomerase reverse transcriptase gene (TERT), tumor protein p53 gene (TP53), and Yes associated protein 1 gene (YAP1), on the basis of prior anecdotal association with lung cancer or genome-wide association studies. Among 555 lung adenocarcinoma cases, we detected 14 pathogenic mutations in five genes; they occurred at a frequency of 2.5% and represented an OR of 66 (95% confidence interval: 33-125, p mutations fell most commonly in ATM (50%), followed by TP53, BRCA2, EGFR, and PARK2. Most (86%) of these variants had been reported in other familial cancer syndromes. Another 12 cases (2%) carried ultrarare variants that were predicted to be deleterious by three protein prediction programs; these most frequently involved ATM and BRCA2. A subset of patients with lung adenocarcinoma, at least 2.5% to 4.5%, carry germline variants that have been linked to cancer risk in Mendelian syndromes. The genes fall most frequently in DNA repair pathways. Our data indicate that patients with lung adenocarcinoma, similar to other solid tumors, include a subset of patients with inherited susceptibility. Copyright © 2017 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

  2. Gene therapy and peripheral nerve repair: a perspective

    Directory of Open Access Journals (Sweden)

    Stefan A. Hoyng

    2015-07-01

    Full Text Available Clinical phase I/II studies have demonstrated the safety of gene therapy for a variety of central nervous system disorders, including Canavan’s, Parkinson’s and Alzheimer’s disease, retinal diseases and pain. The majority of gene therapy studies in the CNS have used adeno-associated viral vectors (AAV and the first AAV-based therapeutic, a vector encoding lipoprotein lipase, is now marketed in Europe under the name Glybera. These remarkable advances may become relevant to translational research on gene therapy to promote peripheral nervous system (PNS repair. This short review first summarizes the results of gene therapy in animal models for peripheral nerve repair. Secondly, we identify key areas of future research in the domain of PNS-gene therapy. Finally, a perspective is provided on the path to clinical translation of PNS gene therapy for traumatic nerve injuries. In the latter section we discuss the route and mode of delivery of the vector to human patients, the efficacy and safety of the vector, and the choice of the patient population for a first possible proof-of-concept clinical study.

  3. Arsenic Resistance and Prevalence of Arsenic Resistance Genes in Campylobacter jejuni and Campylobacter coli Isolated from Retail Meats

    OpenAIRE

    Noormohamed, Aneesa; Fakhr, Mohamed K.

    2013-01-01

    Studies that investigate arsenic resistance in the foodborne bacterium Campylobacter are limited. A total of 552 Campylobacter isolates (281 Campylobacter jejuni and 271 Campylobacter coli) isolated from retail meat samples were subjected to arsenic resistance profiling using the following arsenic compounds: arsanilic acid (4–2,048 μg/mL), roxarsone (4–2048 μg/mL), arsenate (16–8,192 μg/mL) and arsenite (4–2,048 μg/mL). A total of 223 of these isolates (114 Campylobacter jejuni and 109 Campyl...

  4. Induction of a mutant phenotype in human repair proficient cells after overexpression of a mutated human DNA repair gene.

    NARCIS (Netherlands)

    P.B.G.M. Belt; M.F. van Oostenrijk; H. Odijk (Hanny); J.H.J. Hoeijmakers (Jan); C.M.P. Backendorf (Claude)

    1991-01-01

    textabstractAntisense and mutated cDNA of the human excision repair gene ERCC-1 were overexpressed in repair efficient HeLa cells by means of an Epstein-Barr-virus derived CDNA expression vector. Whereas antisense RNA did not influence the survival of the transfected cells, a mutated cDNA generating

  5. Microsatellite Instability Use in Mismatch Repair Gene Sequence Variant Classification

    Directory of Open Access Journals (Sweden)

    Bryony A. Thompson

    2015-03-01

    Full Text Available Inherited mutations in the DNA mismatch repair genes (MMR can cause MMR deficiency and increased susceptibility to colorectal and endometrial cancer. Microsatellite instability (MSI is the defining molecular signature of MMR deficiency. The clinical classification of identified MMR gene sequence variants has a direct impact on the management of patients and their families. For a significant proportion of cases sequence variants of uncertain clinical significance (also known as unclassified variants are identified, constituting a challenge for genetic counselling and clinical management of families. The effect on protein function of these variants is difficult to interpret. The presence or absence of MSI in tumours can aid in determining the pathogenicity of associated unclassified MMR gene variants. However, there are some considerations that need to be taken into account when using MSI for variant interpretation. The use of MSI and other tumour characteristics in MMR gene sequence variant classification will be explored in this review.

  6. Non-DBS DNA Repair Genes Regulate Radiation-induced Cytogenetic Damage Repair and Cell Cycle Progression

    Science.gov (United States)

    Zhang, Ye; Rohde, Larry H.; Emami, Kamal; Casey, Rachael; Wu, Honglu

    2008-01-01

    Changes of gene expression profile are one of the most important biological responses in living cells after ionizing radiation (IR) exposure. Although some studies have shown that genes up-regulated by IR may play important roles in DNA damage repair, the relationship between the regulation of gene expression by IR, particularly genes not known for their roles in DSB repair, and its impact on cytogenetic responses has not been systematically studied. In the present study, the expression of 25 genes selected on the basis of their transcriptional changes in response to IR was individually knocked down by transfection with small interfering RNA in human fibroblast cells. The purpose of this study is to identify new roles of these selected genes on regulating DSB repair and cell cycle progression , as measured in the micronuclei formation and chromosome aberration. In response to IR, the formation of MN was significantly increased by suppressed expression of 5 genes: Ku70 in the DSB repair pathway, XPA in the NER pathway, RPA1 in the MMR pathway, and RAD17 and RBBP8 in cell cycle control. Knocked-down expression of 4 genes (MRE11A, RAD51 in the DSB pathway, SESN1, and SUMO1) significantly inhibited cell cycle progression, possibly because of severe impairment of DNA damage repair. Furthermore, loss of XPA, P21, or MLH1 expression resulted in both significantly enhanced cell cycle progression and increased yields of chromosome aberrations, indicating that these gene products modulate both cell cycle control and DNA damage repair. Most of the 11 genes that affected cytogenetic responses are not known to have clear roles influencing DBS repair. Nine of these 11 genes were up-regulated in cells exposed to gamma radiation, suggesting that genes transcriptionally modulated by IR were critical to regulate the biological consequences after IR.

  7. Association of Cardiometabolic Genes with Arsenic Metabolism Biomarkers in American Indian Communities: The Strong Heart Family Study (SHFS).

    Science.gov (United States)

    Balakrishnan, Poojitha; Vaidya, Dhananjay; Franceschini, Nora; Voruganti, V Saroja; Gribble, Matthew O; Haack, Karin; Laston, Sandra; Umans, Jason G; Francesconi, Kevin A; Goessler, Walter; North, Kari E; Lee, Elisa; Yracheta, Joseph; Best, Lyle G; MacCluer, Jean W; Kent, Jack; Cole, Shelley A; Navas-Acien, Ana

    2017-01-01

    Metabolism of inorganic arsenic (iAs) is subject to inter-individual variability, which is explained partly by genetic determinants. We investigated the association of genetic variants with arsenic species and principal components of arsenic species in the Strong Heart Family Study (SHFS). We examined variants previously associated with cardiometabolic traits (~ 200,000 from Illumina Cardio MetaboChip) or arsenic metabolism and toxicity (670) among 2,428 American Indian participants in the SHFS. Urine arsenic species were measured by high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS), and percent arsenic species [iAs, monomethylarsonate (MMA), and dimethylarsinate (DMA), divided by their sum × 100] were logit transformed. We created two orthogonal principal components that summarized iAs, MMA, and DMA and were also phenotypes for genetic analyses. Linear regression was performed for each phenotype, dependent on allele dosage of the variant. Models accounted for familial relatedness and were adjusted for age, sex, total arsenic levels, and population stratification. Single nucleotide polymorphism (SNP) associations were stratified by study site and were meta-analyzed. Bonferroni correction was used to account for multiple testing. Variants at 10q24 were statistically significant for all percent arsenic species and principal components of arsenic species. The index SNP for iAs%, MMA%, and DMA% (rs12768205) and for the principal components (rs3740394, rs3740393) were located near AS3MT, whose gene product catalyzes methylation of iAs to MMA and DMA. Among the candidate arsenic variant associations, functional SNPs in AS3MT and 10q24 were most significant (p association study supports the role of common variants in arsenic metabolism, particularly AS3MT and 10q24. Citation: Balakrishnan P, Vaidya D, Franceschini N, Voruganti VS, Gribble MO, Haack K, Laston S, Umans JG, Francesconi KA, Goessler W, North KE, Lee E, Yracheta

  8. Identifying arsenic trioxide (ATO) functions in leukemia cells by using time series gene expression profiles.

    Science.gov (United States)

    Yang, Hong; Lin, Shan; Cui, Jingru

    2014-02-10

    Arsenic trioxide (ATO) is presently the most active single agent in the treatment of acute promyelocytic leukemia (APL). In order to explore the molecular mechanism of ATO in leukemia cells with time series, we adopted bioinformatics strategy to analyze expression changing patterns and changes in transcription regulation modules of time series genes filtered from Gene Expression Omnibus database (GSE24946). We totally screened out 1847 time series genes for subsequent analysis. The KEGG (Kyoto encyclopedia of genes and genomes) pathways enrichment analysis of these genes showed that oxidative phosphorylation and ribosome were the top 2 significantly enriched pathways. STEM software was employed to compare changing patterns of gene expression with assigned 50 expression patterns. We screened out 7 significantly enriched patterns and 4 tendency charts of time series genes. The result of Gene Ontology showed that functions of times series genes mainly distributed in profiles 41, 40, 39 and 38. Seven genes with positive regulation of cell adhesion function were enriched in profile 40, and presented the same first increased model then decreased model as profile 40. The transcription module analysis showed that they mainly involved in oxidative phosphorylation pathway and ribosome pathway. Overall, our data summarized the gene expression changes in ATO treated K562-r cell lines with time and suggested that time series genes mainly regulated cell adhesive. Furthermore, our result may provide theoretical basis of molecular biology in treating acute promyelocytic leukemia. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Assessing the microbial community and functional genes in a vertical soil profile with long-term arsenic contamination.

    Directory of Open Access Journals (Sweden)

    Jinbo Xiong

    Full Text Available Arsenic (As contamination in soil and groundwater has become a serious problem to public health. To examine how microbial communities and functional genes respond to long-term arsenic contamination in vertical soil profile, soil samples were collected from the surface to the depth of 4 m (with an interval of 1 m after 16-year arsenic downward infiltration. Integrating BioLog and functional gene microarray (GeoChip 3.0 technologies, we showed that microbial metabolic potential and diversity substantially decreased, and community structure was markedly distinct along the depth. Variations in microbial community functional genes, including genes responsible for As resistance, carbon and nitrogen cycling, phosphorus utilization and cytochrome c oxidases were detected. In particular, changes in community structures and activities were correlated with the biogeochemical features along the vertical soil profile when using the rbcL and nifH genes as biomarkers, evident for a gradual transition from aerobic to anaerobic lifestyles. The C/N showed marginally significant correlations with arsenic resistance (p = 0.069 and carbon cycling genes (p = 0.073, and significant correlation with nitrogen fixation genes (p = 0.024. The combination of C/N, NO(3 (- and P showed the highest correlation (r = 0.779, p = 0.062 with the microbial community structure. Contradict to our hypotheses, a long-term arsenic downward infiltration was not the primary factor, while the spatial isolation and nutrient availability were the key forces in shaping the community structure. This study provides new insights about the heterogeneity of microbial community metabolic potential and future biodiversity preservation for arsenic bioremediation management.

  10. Approaches to diagnose DNA mismatch repair gene defects in cancer.

    Science.gov (United States)

    Peña-Diaz, Javier; Rasmussen, Lene Juel

    2016-02-01

    The DNA repair pathway mismatch repair (MMR) is responsible for the recognition and correction of DNA biosynthetic errors caused by inaccurate nucleotide incorporation during replication. Faulty MMR leads to failure to address the mispairs or insertion deletion loops (IDLs) left behind by the replicative polymerases and results in increased mutation load at the genome. The realization that defective MMR leads to a hypermutation phenotype and increased risk of tumorigenesis highlights the relevance of this pathway for human disease. The association of MMR defects with increased risk of cancer development was first observed in colorectal cancer patients that carried inactivating germline mutations in MMR genes and the disease was named as hereditary non-polyposis colorectal cancer (HNPCC). Currently, a growing list of cancers is found to be MMR defective and HNPCC has been renamed Lynch syndrome (LS) partly to include the associated risk of developing extra-colonic cancers. In addition, a number of non-hereditary, mostly epigenetic, alterations of MMR genes have been described in sporadic tumors. Besides conferring a strong cancer predisposition, genetic or epigenetic inactivation of MMR genes also renders cells resistant to some chemotherapeutic agents. Therefore, diagnosis of MMR deficiency has important implications for the management of the patients, the surveillance of their relatives in the case of LS and for the choice of treatment. Some of the alterations found in MMR genes have already been well defined and their pathogenicity assessed. Despite this substantial wealth of knowledge, the effects of a large number of alterations remain uncharacterized (variants of uncertain significance, VUSs). The advent of personalized genomics is likely to increase the list of VUSs found in MMR genes and anticipates the need of diagnostic tools for rapid assessment of their pathogenicity. This review describes current tools and future strategies for addressing the relevance

  11. Polymorphism of the DNA Base Excision Repair Genes in Keratoconus

    Science.gov (United States)

    Wojcik, Katarzyna A.; Synowiec, Ewelina; Sobierajczyk, Katarzyna; Izdebska, Justyna; Blasiak, Janusz; Szaflik, Jerzy; Szaflik, Jacek P.

    2014-01-01

    Keratoconus (KC) is a degenerative corneal disorder for which the exact pathogenesis is not yet known. Oxidative stress is reported to be associated with this disease. The stress may damage corneal biomolecules, including DNA, and such damage is primarily removed by base excision repair (BER). Variation in genes encoding BER components may influence the effectiveness of corneal cells to cope with oxidative stress. In the present work we genotyped 5 polymorphisms of 4 BER genes in 284 patients and 353 controls. The A/A genotype of the c.–1370T>A polymorphism of the DNA polymerase γ (POLG) gene was associated with increased occurrence of KC, while the A/T genotype was associated with decreased occurrence of KC. The A/G genotype and the A allele of the c.1196A>G polymorphism of the X-ray repair cross-complementing group 1 (XRCC1) were associated with increased, and the G/G genotype and the G allele, with decreased KC occurrence. Also, the C/T and T as well as C/C genotypes and alleles of the c.580C>T polymorphism of the same gene displayed relationship with KC occurrence. Neither the g.46438521G>C polymorphism of the Nei endonuclease VIII-like 1 (NEIL1) nor the c.2285T>C polymorphism of the poly(ADP-ribose) polymerase-1 (PARP-1) was associated with KC. In conclusion, the variability of the XRCC1 and POLG genes may play a role in KC pathogenesis and determine the risk of this disease. PMID:25356504

  12. Polymorphism of the DNA Base Excision Repair Genes in Keratoconus

    Directory of Open Access Journals (Sweden)

    Katarzyna A. Wojcik

    2014-10-01

    Full Text Available Keratoconus (KC is a degenerative corneal disorder for which the exact pathogenesis is not yet known. Oxidative stress is reported to be associated with this disease. The stress may damage corneal biomolecules, including DNA, and such damage is primarily removed by base excision repair (BER. Variation in genes encoding BER components may influence the effectiveness of corneal cells to cope with oxidative stress. In the present work we genotyped 5 polymorphisms of 4 BER genes in 284 patients and 353 controls. The A/A genotype of the c.–1370T>A polymorphism of the DNA polymerase γ (POLG gene was associated with increased occurrence of KC, while the A/T genotype was associated with decreased occurrence of KC. The A/G genotype and the A allele of the c.1196A>G polymorphism of the X-ray repair cross-complementing group 1 (XRCC1 were associated with increased, and the G/G genotype and the G allele, with decreased KC occurrence. Also, the C/T and T as well as C/C genotypes and alleles of the c.580C>T polymorphism of the same gene displayed relationship with KC occurrence. Neither the g.46438521G>C polymorphism of the Nei endonuclease VIII-like 1 (NEIL1 nor the c.2285T>C polymorphism of the poly(ADP-ribose polymerase-1 (PARP-1 was associated with KC. In conclusion, the variability of the XRCC1 and POLG genes may play a role in KC pathogenesis and determine the risk of this disease.

  13. Altered Gene Expression by Low-Dose Arsenic Exposure in Humans and Cultured Cardiomyocytes: Assessment by Real-Time PCR Arrays

    Directory of Open Access Journals (Sweden)

    Judy Mumford

    2011-06-01

    Full Text Available Chronic arsenic exposure results in higher risk of skin, lung, and bladder cancer, as well as cardiovascular disease and diabetes. The purpose of this study was to investigate the effects on expression of selected genes in the blood lymphocytes from 159 people exposed chronically to arsenic in their drinking water using a novel RT-PCR TaqMan low-density array (TLDA. We found that expression of tumor necrosis factor-α (TNF-α, which activates both inflammation and NF-κB-dependent survival pathways, was strongly associated with water and urinary arsenic levels. Expression of KCNA5, which encodes a potassium ion channel protein, was positively associated with water and toe nail arsenic levels. Expression of 2 and 11 genes were positively associated with nail and urinary arsenic, respectively. Because arsenic exposure has been reported to be associated with long QT intervals and vascular disease in humans, we also used this TLDA for analysis of gene expression in human cardiomyocytes exposed to arsenic in vitro. Expression of the ion-channel genes CACNA1, KCNH2, KCNQ1 and KCNE1 were down-regulated by 1-mM arsenic. Alteration of some common pathways, including those involved in oxidative stress, inflammatory signaling, and ion-channel function, may underlay the seemingly disparate array of arsenic-associated diseases, such as cancer, cardiovascular disease, and diabetes.

  14. Chronic arsenic toxicity: Studies in West Bengal, India

    Directory of Open Access Journals (Sweden)

    Debendranath Guha Mazumder

    2011-09-01

    Full Text Available Chronic arsenic toxicity (arsenicosis as a result of drinking arsenic-contaminated groundwater is a major environmental health hazard throughout the world, including India. A lot of research on health effects, including genotoxic effect of chronic arsenic toxicity in humans, have been carried out in West Bengal during the last 2 decades. A review of literature including information available from West Bengal has been made to characterize the problem. Scientific journals, monographs, and proceedings of conferences with regard to human health effects, including genotoxicity, of chronic arsenic toxicity have been reviewed. Pigmentation and keratosis are the specific skin diseases characteristic of chronic arsenic toxicity. However, in West Bengal, it was found to produce various systemic manifestations, such as chronic lung disease, characterized by chronic bronchitis, chronic obstructive and/or restrictive pulmonary disease, and bronchiectasis; liver diseases, such as non cirrhotic portal fibrosis; polyneuropathy; peripheral vascular disease; hypertension; nonpitting edema of feet/hands; conjunctival congestion; weakness; and anemia. High concentrations of arsenic, greater than or equal to 200 μg/L, during pregnancy were found to be associated with a sixfold increased risk for stillbirth. Cancers of skin, lung, and urinary bladder are the important cancers associated with this toxicity. Of the various genotoxic effects of arsenic in humans, chromosomal aberration and increased frequency of micronuclei in different cell types have been found to be significant. Various probable mechanisms have been incriminated to cause DNA damage because of chronic arsenic toxicity. The results of the study in West Bengal suggest that deficiency in DNA repair capacity, perturbation of methylation of promoter region of p53 and p16 genes, and genomic methylation alteration may be involved in arsenic-induced disease manifestation in humans. P53 polymorphism has been

  15. Sex-specific patterns and deregulation of endocrine pathways in the gene expression profiles of Bangladeshi adults exposed to arsenic contaminated drinking water

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, Alexandra; Chervona, Yana [New York University School of Medicine, Nelson Institute of Environmental Medicine, Tuxedo, NY (United States); Hall, Megan [Department of Epidemiology, Mailman School of Public Health, Columbia University, New York (United States); Kluz, Thomas [New York University School of Medicine, Nelson Institute of Environmental Medicine, Tuxedo, NY (United States); Gamble, Mary V., E-mail: mvg7@columbia.edu [Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York (United States); Costa, Max, E-mail: Max.Costa@nyumc.org [New York University School of Medicine, Nelson Institute of Environmental Medicine, Tuxedo, NY (United States)

    2015-05-01

    Arsenic contamination of drinking water occurs globally and is associated with numerous diseases including skin, lung and bladder cancers, and cardiovascular disease. Recent research indicates that arsenic may be an endocrine disruptor. This study was conducted to evaluate the nature of gene expression changes among males and females exposed to arsenic contaminated water in Bangladesh at high and low doses. Twenty-nine (55% male) Bangladeshi adults with water arsenic exposure ranging from 50 to 1000 μg/L were selected from the Folic Acid Creatinine Trial. RNA was extracted from peripheral blood mononuclear cells for gene expression profiling using Affymetrix 1.0 ST arrays. Differentially expressed genes were assessed between high and low exposure groups for males and females separately and findings were validated using quantitative real-time PCR. There were 534 and 645 differentially expressed genes (p < 0.05) in the peripheral blood mononuclear cells of males and females, respectively, when high and low water arsenic exposure groups were compared. Only 43 genes overlapped between the two sexes, with 29 changing in opposite directions. Despite the difference in gene sets both males and females exhibited common biological changes including deregulation of 17β-hydroxysteroid dehydrogenase enzymes, deregulation of genes downstream of Sp1 (specificity protein 1) transcription factor, and prediction of estrogen receptor alpha as a key hub in cardiovascular networks. Arsenic-exposed adults exhibit sex-specific gene expression profiles that implicate involvement of the endocrine system. Due to arsenic's possible role as an endocrine disruptor, exposure thresholds for arsenic may require different parameters for males and females. - Highlights: • Males and females exhibit unique gene expression changes in response to arsenic. • Only 23 genes are common among the differentially expressed genes for the sexes. • Male and female gene lists exhibit common

  16. Gene specific damage and repair after treatment of cells with UV and chemotherapeutical agents

    Energy Technology Data Exchange (ETDEWEB)

    Bohr, V.A. (Division of Cancer Treatment, National Cancer Institute, NIH, Bethesda, MD (USA))

    1991-01-01

    The authors have previously demonstrated preferential DNA repair of active genes in mammalian cells. The methodology involves the use of a specific endonuclease or other more direct approaches to create nicks at sites of damage followed by quantitative Southern analysis and probing for specific genes. Initially, they used pyrimidine dimer specific endonuclease to detect pyrimidine dimers after UV irradiation. They now also use the bacterial enzyme ABC excinuclease to examine the DNA damage and repair of a number of adducts other than pyrimidine dimers in specific genes. They can detect gene specific alkylation damage by creating nicks via depurination and alkaline hydrolysis. In our assay for preferential repair, they compare the efficiency of repair in the DHFR gene to that in the 3{prime} flanking, non-coding region to the gene. In CHO cells, UV induced pyrimidine dimers are efficiently repaired from the active DHFR gene, but not from the inactive region. They have demonstrated that the 6-4 photoproducts are also preferentially repaired and that they are removed faster from the regions studied than pyrimidine dimers. Using similar approaches, they find that DNA adducts and crosslinks caused by cisplatinum are preferentially repaired in the active gene compared to the inactive regions and to the inactive c-fos oncogene. Also, nitrogen mustard and methylnitrosurea damage is preferentially repaired whereas dimethylsulphate damage is not. NAAAF adducts do not appear to be preferentially repaired in this system. 32 refs.

  17. Arsenic Induces Polyadenylation of Canonical Histone mRNA by Down-regulating Stem-Loop-binding Protein Gene Expression*

    Science.gov (United States)

    Brocato, Jason; Fang, Lei; Chervona, Yana; Chen, Danqi; Kiok, Kathrin; Sun, Hong; Tseng, Hsiang-Chi; Xu, Dazhong; Shamy, Magdy; Jin, Chunyuan; Costa, Max

    2014-01-01

    The replication-dependent histone genes are the only metazoan genes whose messenger RNA (mRNA) does not terminate with a poly(A) tail at the 3′-end. Instead, the histone mRNAs display a stem-loop structure at their 3′-end. Stem-loop-binding protein (SLBP) binds the stem-loop and regulates canonical histone mRNA metabolism. Here we report that exposure to arsenic, a carcinogenic metal, decreased cellular levels of SLBP by inducing its proteasomal degradation and inhibiting SLBP transcription via epigenetic mechanisms. Notably, arsenic exposure dramatically increased polyadenylation of canonical histone H3.1 mRNA possibly through down-regulation of SLBP expression. The polyadenylated H3.1 mRNA induced by arsenic was not susceptible to normal degradation that occurs at the end of S phase, resulting in continued presence into mitosis, increased total H3.1 mRNA, and increased H3 protein levels. Excess expression of canonical histones have been shown to increase sensitivity to DNA damage as well as increase the frequency of missing chromosomes and induce genomic instability. Thus, polyadenylation of canonical histone mRNA following arsenic exposure may contribute to arsenic-induced carcinogenesis. PMID:25266719

  18. Imprinted Genes and the Environment: Links to the Toxic Metals Arsenic, Cadmium and Lead

    Directory of Open Access Journals (Sweden)

    Lisa Smeester

    2014-06-01

    Full Text Available Imprinted genes defy rules of Mendelian genetics with their expression tied to the parent from whom each allele was inherited. They are known to play a role in various diseases/disorders including fetal growth disruption, lower birth weight, obesity, and cancer. There is increasing interest in understanding their influence on environmentally-induced disease. The environment can be thought of broadly as including chemicals present in air, water and soil, as well as food. According to the Agency for Toxic Substances and Disease Registry (ATSDR, some of the highest ranking environmental chemicals of concern include metals/metalloids such as arsenic, cadmium, lead and mercury. The complex relationships between toxic metal exposure, imprinted gene regulation/expression and health outcomes are understudied. Herein we examine trends in imprinted gene biology, including an assessment of the imprinted genes and their known functional roles in the cell, particularly as they relate to toxic metals exposure and disease. The data highlight that many of the imprinted genes have known associations to developmental diseases and are enriched for their role in the TP53 and AhR pathways. Assessment of the promoter regions of the imprinted genes resulted in the identification of an enrichment of binding sites for two transcription factor families, namely the zinc finger family II and PLAG transcription factors. Taken together these data contribute insight into the complex relationships between toxic metals in the environment and imprinted gene biology.

  19. Imprinted genes and the environment: links to the toxic metals arsenic, cadmium, lead and mercury.

    Science.gov (United States)

    Smeester, Lisa; Yosim, Andrew E; Nye, Monica D; Hoyo, Cathrine; Murphy, Susan K; Fry, Rebecca C

    2014-06-11

    Imprinted genes defy rules of Mendelian genetics with their expression tied to the parent from whom each allele was inherited. They are known to play a role in various diseases/disorders including fetal growth disruption, lower birth weight, obesity, and cancer. There is increasing interest in understanding their influence on environmentally-induced disease. The environment can be thought of broadly as including chemicals present in air, water and soil, as well as food. According to the Agency for Toxic Substances and Disease Registry (ATSDR), some of the highest ranking environmental chemicals of concern include metals/metalloids such as arsenic, cadmium, lead and mercury. The complex relationships between toxic metal exposure, imprinted gene regulation/expression and health outcomes are understudied. Herein we examine trends in imprinted gene biology, including an assessment of the imprinted genes and their known functional roles in the cell, particularly as they relate to toxic metals exposure and disease. The data highlight that many of the imprinted genes have known associations to developmental diseases and are enriched for their role in the TP53 and AhR pathways. Assessment of the promoter regions of the imprinted genes resulted in the identification of an enrichment of binding sites for two transcription factor families, namely the zinc finger family II and PLAG transcription factors. Taken together these data contribute insight into the complex relationships between toxic metals in the environment and imprinted gene biology.

  20. Hypomethylation of inflammatory genes (COX2, EGR1, and SOCS3) and increased urinary 8-nitroguanine in arsenic-exposed newborns and children.

    Science.gov (United States)

    Phookphan, Preeyaphan; Navasumrit, Panida; Waraprasit, Somchamai; Promvijit, Jeerawan; Chaisatra, Krittinee; Ngaotepprutaram, Thitirat; Ruchirawat, Mathuros

    2017-02-01

    Early-life exposure to arsenic increases risk of developing a variety of non-malignant and malignant diseases. Arsenic-induced carcinogenesis may be mediated through epigenetic mechanisms and pathways leading to inflammation. Our previous study reported that prenatal arsenic exposure leads to increased mRNA expression of several genes related to inflammation, including COX2, EGR1, and SOCS3. This study aimed to investigate the effects of arsenic exposure on promoter DNA methylation and mRNA expression of these inflammatory genes (COX2, EGR1, and SOCS3), as well as the generation of 8-nitroguanine, which is a mutagenic DNA lesion involved in inflammation-related carcinogenesis. Prenatally arsenic-exposed newborns had promoter hypomethylation of COX2, EGR1, and SOCS3 in cord blood lymphocytes (parsenic-exposed children showed a significant hypomethylation of these genes in salivary DNA (pArsenic accumulation in toenails was negatively correlated with hypomethylation of these genes and positively correlated with levels of 8-nitroguanine. These results indicated that early-life exposure to arsenic causes hypomethylation of COX2, EGR1, and SOCS3, increases mRNA expression of these genes, and increases 8-nitroguanine formation. These effects may be linked to mechanisms of arsenic-induced inflammation and cancer development later in life. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Gene-specific differential DNA methylation and chronic arsenic exposure in an epigenome-wide association study of adults in Bangladesh.

    Science.gov (United States)

    Argos, Maria; Chen, Lin; Jasmine, Farzana; Tong, Lin; Pierce, Brandon L; Roy, Shantanu; Paul-Brutus, Rachelle; Gamble, Mary V; Harper, Kristin N; Parvez, Faruque; Rahman, Mahfuzar; Rakibuz-Zaman, Muhammad; Slavkovich, Vesna; Baron, John A; Graziano, Joseph H; Kibriya, Muhammad G; Ahsan, Habibul

    2015-01-01

    Inorganic arsenic is one of the most common naturally occurring contaminants found in the environment. Arsenic is associated with a number of health outcomes, with epigenetic modification suggested as a potential mechanism of toxicity. Among a sample of 400 adult participants, we evaluated the association between arsenic exposure, as measured by blood and urinary total arsenic concentrations, and epigenome-wide white blood cell DNA methylation. We used linear regression models to examine the associations between arsenic exposure and methylation at each CpG site, adjusted for sex, age, and batch. Differentially methylated loci were subsequently examined in relation to corresponding gene expression for functional evidence of gene regulation. In adjusted analyses, we observed four differentially methylated CpG sites with urinary total arsenic concentration and three differentially methylated CpG sites with blood arsenic concentration, based on the Bonferroni-corrected significance threshold of p Methylation of PLA2G2C (probe cg04605617) was the most significantly associated locus in relation to both urinary (p = 3.40 × 10(-11)) and blood arsenic concentrations (p = 1.48 × 10(-11)). Three additional novel methylation loci-SQSTM1 (cg01225779), SLC4A4 (cg06121226), and IGH (cg13651690)--were also significantly associated with arsenic exposure. Further, there was evidence of methylation-related gene regulation based on gene expression for a subset of differentially methylated loci. We observed significant associations between arsenic exposure and gene-specific differential white blood cell DNA methylation, suggesting that epigenetic modifications may be an important pathway underlying arsenic toxicity. The specific differentially methylated loci identified may inform potential pathways for future interventions.

  2. Molecular characterization of the human excision repair gene ERCC-1: cDNA cloning and aminoacid homology with the yeast DNA repair gene RAD10.

    NARCIS (Netherlands)

    M. van Duin (Mark); J. de Wit (Jan); H. Odijk (Hanny); A. Westerveld (Andries); A. Yasui (Akira); M.H.M. Koken (Marcel); J.H.J. Hoeijmakers (Jan); D. Bootsma (Dirk)

    1986-01-01

    textabstractThe human excision repair gene ERCC-7 was cloned after DNA mediated gene transfer to the CHO mutant 43-38, which is sensitive to ultraviolet light and mitomycin-C. We describe the cloning and sequence analysis of the ERCC-7 cDNA and partial characterization of the gene. ERCC.1 has a size

  3. Transplacental exposure to inorganic arsenic at a hepatocarcinogenic dose induces fetal gene expression changes in mice indicative of aberrant estrogen signaling and disrupted steroid metabolism

    Science.gov (United States)

    Liu, Jie; Xie, Yaxiong; Cooper, Ryan; Ducharme, Danica M.K.; Tennant, Raymond; Diwan, Bhalchandra A.; Waalkes, Michael P.

    2009-01-01

    Exposure to inorganic arsenic in utero in C3H mice produces hepatocellular carcinoma in male offspring when they reach adulthood. To help define the molecular events associated with the fetal onset of arsenic hepatocarcinogenesis, pregnant C3H mice were given drinking water containing 0 (control) or 85 ppm arsenic from day 8 to 18 of gestation. At the end of the arsenic exposure period, male fetal livers were removed and RNA isolated for microarray analysis using 22K oligo chips. Arsenic exposure in utero produced significant (p inorganic arsenic during a critical period in development significantly alters the expression of various genes encoding estrogen signaling and steroid or methionine metabolism. These alterations could disrupt genetic programming at the very early life-stage, which could impact tumor formation much later in adulthood. PMID:17350061

  4. DNA mismatch repair preferentially protects genes from mutation.

    Science.gov (United States)

    Belfield, Eric J; Ding, Zhong Jie; Jamieson, Fiona J C; Visscher, Anne M; Zheng, Shao Jian; Mithani, Aziz; Harberd, Nicholas P

    2017-12-12

    Mutation is the source of genetic variation and fuels biological evolution. Many mutations first arise as DNA replication errors. These errors subsequently evade correction by cellular DNA repair, for example, by the well-known DNA mismatch repair (MMR) mechanism. Here, we determine the genome-wide effects of MMR on mutation. We first identify almost 9000 mutations accumulated over five generations in eight MMR-deficient mutation accumulation (MA) lines of the model plant species, Arabidopsis thaliana We then show that MMR deficiency greatly increases the frequency of both smaller-scale insertions and deletions (indels) and of single-nucleotide variant (SNV) mutations. Most indels involve A or T nucleotides and occur preferentially in homopolymeric (poly A or poly T) genomic stretches. In addition, we find that the likelihood of occurrence of indels in homopolymeric stretches is strongly related to stretch length, and that this relationship causes ultrahigh localized mutation rates in specific homopolymeric stretch regions. For SNVs, we show that MMR deficiency both increases their frequency and changes their molecular mutational spectrum, causing further enhancement of the GC to AT bias characteristic of organisms with normal MMR function. Our final genome-wide analyses show that MMR deficiency disproportionately increases the numbers of SNVs in genes, rather than in nongenic regions of the genome. This latter observation indicates that MMR preferentially protects genes from mutation and has important consequences for understanding the evolution of genomes during both natural selection and human tumor growth. © 2018 Belfield et al.; Published by Cold Spring Harbor Laboratory Press.

  5. Polymorphisms of Selected DNA Repair Genes and Lung Cancer in Chromium Exposure.

    Science.gov (United States)

    Halasova, E; Matakova, T; Skerenova, M; Krutakova, M; Slovakova, P; Dzian, A; Javorkova, S; Pec, M; Kypusova, K; Hamzik, J

    2016-01-01

    Chromium is a well-known mutagen and carcinogen involved in lung cancer development. DNA repair genes play an important role in the elimination of genetic changes caused by chromium exposure. In the present study, we investigated the polymorphisms of the following DNA repair genes: XRCC3, participating in the homologous recombination repair, and hMLH1 and hMSH2, functioning in the mismatch repair. We focused on the risk the polymorphisms present in the development of lung cancer regarding the exposure to chromium. We analyzed 106 individuals; 45 patients exposed to chromium with diagnosed lung cancer and 61 healthy controls. Genotypes were determined by a PCR-RFLP method. We unravelled a potential for increased risk of lung cancer development in the hMLH1 (rs1800734) AA genotype in the recessive model. In conclusion, gene polymorphisms in the DNA repair genes underscores the risk of lung cancer development in chromium exposed individuals.

  6. Gene expression of the mismatch repair gene MSH2 in primary colorectal cancer

    DEFF Research Database (Denmark)

    Jensen, Lars Henrik; Kuramochi, Hidekazu; Crüger, Dorthe Gylling

    2011-01-01

    Microsatellite instability (MSI) is caused by defective mismatch repair (MMR) and is one of the very few molecular markers with proven clinical importance in colorectal cancer with respect to heredity, prognosis, and treatment effect. The gene expression of the MMR gene MSH2 may be a quantitative...... marker for the level of MMR and a potential molecular marker with clinical relevance. The aim was to investigate the gene expression of MSH2 in primary operable colorectal cancer in correlation with MSI, protein expression, and promoter hypermethylation. In a cohort of 210 patients, the primary tumor...... and lymphnode metastases were analyzed with immunohistochemistry, methylation and MSI analyses, and quantitative polymerase chain reaction (PCR). The median gene expression of MSH2 was 1.00 (range 0.16-11.2, quartiles 0.70-1.51) and there was good agreement between the gene expression in primary tumor and lymph...

  7. [Construction of subtractive cDNA library of apoptosis-related genes in NB4 cells treated by arsenic trioxide].

    Science.gov (United States)

    Di, Chunhong; Gu, Shaohua; Tan, Xiaohua; Xian, Lingling; Wu, Qihan; Yang, Lei

    2009-02-01

    Construct the gene library of apoptosis related genes in acute promyelocytic leukemia (APL) cell line NB4 cells treated by arsenic trioxide to clarify the apoptotic mechanism of NB4 cells. APL cell line NB4 cells treated with or without arsenic trioxide for 24 hours. Total RNA was extracted and suppress subtractive hybridization (SSH) was conducted according to the manual. With the cDNA of the apoptosis cells as the tester and that of control cells as the driver, forward and reverse hybridization was performed. Differentially expressed genes were linked with pGEM-Teasy cloning vector and transformed into E. coli DH5alpha. The positive clones were screened by blue and white spot. PCR were used to amplify these genes. The subtractive cDNA libraries related with apoptosis of NB4 cells were successfully constructed. The constructed subtractive libraries are suitable for further study on the functional genes associated with apoptosis ofNB4 cells induced by arsenic trioxide.

  8. GENE EXPRESSION PROFILES IN ARSENIC-TREATED MCF-7 BREAST CANCER CELLS EXPRESSING DIFFERENT LEVELS OF HSP70

    Science.gov (United States)

    Gene expression profiles in arsenic-treated MCF-7 breast cancer cells expressing different levels of HSP70Gail Nelson, Susan Hester, Ernest Winkfield, Jill Barnes, James AllenEnvironmental Carcinogenesis Division, NHEERL, ORD, US Environmental Protection Agency, Rese...

  9. Influence of Morinda citrifolia (Noni) on Expression of DNA Repair Genes in Cervical Cancer Cells.

    Science.gov (United States)

    Gupta, Rakesh Kumar; Bajpai, Deepti; Singh, Neeta

    2015-01-01

    Previous studies have suggested that Morinda citrifolia (Noni) has potential to reduce cancer risk. The purpose of this study was to investigate the effect of Noni, cisplatin, and their combination on DNA repair genes in the SiHa cervical cancer cell line. SiHa cells were cultured and treated with 10% Noni, 10 μg/dl cisplatin or their combination for 24 hours. Post culturing, the cells were pelleted, RNA extracted, and processed for investigating DNA repair genes by real time PCR. The expression of nucleotide excision repair genes ERCC1, ERCC2, and ERCC4 and base excision repair gene XRCC1 was increased 4 fold, 8.9 fold, 4 fold, and 5.5 fold, respectively, on treatment with Noni as compared to untreated controls (p<0.05). In contrast, expression was found to be decreased 22 fold, 13 fold, 16 fold, and 23 fold on treatment with cisplatin (p<0.05). However, the combination of Noni and cisplatin led to an increase of 2 fold, 1.6 fold, 3 fold, 1.2 fold, respectively (p<0.05). Noni enhanced the expression of DNA repair genes by itself and in combination with cisplatin. However, high expression of DNA repair genes at mRNA level only signifies efficient DNA transcription of the above mentioned genes; further investigations are needed to evaluate the DNA repair protein expression.

  10. Repair of some active genes in Cockayne syndrome cells is at the genome overall rate.

    Science.gov (United States)

    Kantor, G J; Bastin, S A

    1995-05-01

    Repair of UV (254 nm)-induced DNA damage in cells from patients with the genetic disease Cockayne syndrome (CS; CS3BE, CS2BE) has been examined in several different genomic regions. These regions include those that contain the actively transcribed beta-actin and adenosine deaminase (ADA) genes and the inactive insulin and 754 loci. The beta-actin, ADA and insulin regions are repaired at about the same rate, one which is equal to the genome overall repair rate. The 754 locus is repaired considerably more slowly. The insulin region is repaired at the same rate in both CS and normal cells as is the 754 locus. The only difference from normal is that the active genes, while repaired well, are not preferentially repaired relative to the genome overall. Our results are consistent with the hypothesis that the repair defect in CS is due to an inactive transcription-repair coupling factor (TRCF). However, the results also indicate that factors other than TRCF and active transcription must also promote repair of some regions relative to others in both normal and CS cells.

  11. Triple Negative Breast Cancers Have a Reduced Expression of DNA Repair Genes

    Science.gov (United States)

    Andreis, Daniele; Bertoni, Ramona; Giardini, Roberto; Fox, Stephen B.; Broggini, Massimo; Bottini, Alberto; Zanoni, Vanessa; Bazzola, Letizia; Foroni, Chiara; Generali, Daniele; Damia, Giovanna

    2013-01-01

    DNA repair is a key determinant in the cellular response to therapy and tumor repair status could play an important role in tailoring patient therapy. Our goal was to evaluate the mRNA of 13 genes involved in different DNA repair pathways (base excision, nucleotide excision, homologous recombination, and Fanconi anemia) in paraffin embedded samples of triple negative breast cancer (TNBC) compared to luminal A breast cancer (LABC). Most of the genes involved in nucleotide excision repair and Fanconi Anemia pathways, and CHK1 gene were significantly less expressed in TNBC than in LABC. PARP1 levels were higher in TNBC than in LABC. In univariate analysis high level of FANCA correlated with an increased overall survival and event free survival in TNBC; however multivariate analyses using Cox regression did not confirm FANCA as independent prognostic factor. These data support the evidence that TNBCs compared to LABCs harbour DNA repair defects. PMID:23825533

  12. Cloning and characterization of the human DNA-excision repair gene ERCC-1

    NARCIS (Netherlands)

    M. van Duin (Michel)

    1988-01-01

    textabstractIt is the aim of the work described in this thesis to isolate and characterize human genes involved DNA excision repair. This will facilitate the understanding of the mechanism of this repair process whereas it also provides an important step to better understand the relationship

  13. DNA repair in human cells: from genetic complementation to isolation of genes.

    NARCIS (Netherlands)

    D. Bootsma (Dirk); A. Westerveld (Andries); J.H.J. Hoeijmakers (Jan)

    1988-01-01

    textabstractThe genetic disease xeroderma pigmentosum (XP) demonstrates the association between defective repair of DNA lesions and cancer. Complementation analysis performed on XP cell strains and on repair deficient rodent cell lines has revealed that at least nine and possibly more than 13 genes

  14. Effects of chronic exposure to arsenic and estrogen on epigenetic regulatory genes expression and epigenetic code in human prostate epithelial cells.

    Directory of Open Access Journals (Sweden)

    Justin N Treas

    Full Text Available Chronic exposures to arsenic and estrogen are known risk factors for prostate cancer. Though the evidence suggests that exposure to arsenic or estrogens can disrupt normal DNA methylation patterns and histone modifications, the mechanisms by which these chemicals induce epigenetic changes are not fully understood. Moreover, the epigenetic effects of co-exposure to these two chemicals are not known. Therefore, the objective of this study was to evaluate the effects of chronic exposure to arsenic and estrogen, both alone and in combination, on the expression of epigenetic regulatory genes, their consequences on DNA methylation, and histone modifications. Human prostate epithelial cells, RWPE-1, chronically exposed to arsenic and estrogen alone and in combination were used for analysis of epigenetic regulatory genes expression, global DNA methylation changes, and histone modifications at protein level. The result of this study revealed that exposure to arsenic, estrogen, and their combination alters the expression of epigenetic regulatory genes and changes global DNA methylation and histone modification patterns in RWPE-1 cells. These changes were significantly greater in arsenic and estrogen combination treated group than individually treated group. The findings of this study will help explain the epigenetic mechanism of arsenic- and/or estrogen-induced prostate carcinogenesis.

  15. DNA-repair gene variants are associated with glioblastoma survival

    DEFF Research Database (Denmark)

    Wibom, Carl; Sjöström, Sara; Henriksson, Roger

    2012-01-01

    Abstract Patient outcome from glioma may be influenced by germline variation. Considering the importance of DNA repair in cancer biology as well as in response to treatment, we studied the relationship between 1458 SNPs, which captured the majority of the common genetic variation in 136 DNA repair...

  16. Prenatal arsenic exposure alters gene expression in the adult liver to a proinflammatory state contributing to accelerated atherosclerosis.

    Directory of Open Access Journals (Sweden)

    J Christopher States

    Full Text Available The mechanisms by which environmental toxicants alter developmental processes predisposing individuals to adult onset chronic disease are not well-understood. Transplacental arsenic exposure promotes atherogenesis in apolipoprotein E-knockout (ApoE(-/- mice. Because the liver plays a central role in atherosclerosis, diabetes and metabolic syndrome, we hypothesized that accelerated atherosclerosis may be linked to altered hepatic development. This hypothesis was tested in ApoE(-/- mice exposed to 49 ppm arsenic in utero from gestational day (GD 8 to term. GD18 hepatic arsenic was 1.2 µg/g in dams and 350 ng/g in fetuses. The hepatic transcriptome was evaluated by microarray analysis to assess mRNA and microRNA abundance in control and exposed pups at postnatal day (PND 1 and PND70. Arsenic exposure altered postnatal developmental trajectory of mRNA and microRNA profiles. We identified an arsenic exposure related 51-gene signature at PND1 and PND70 with several hubs of interaction (Hspa8, IgM and Hnf4a. Gene ontology (GO annotation analyses indicated that pathways for gluconeogenesis and glycolysis were suppressed in exposed pups at PND1, and pathways for protein export, ribosome, antigen processing and presentation, and complement and coagulation cascades were induced by PND70. Promoter analysis of differentially-expressed transcripts identified enriched transcription factor binding sites and clustering to common regulatory sites. SREBP1 binding sites were identified in about 16% of PND70 differentially-expressed genes. Western blot analysis confirmed changes in the liver at PND70 that included increases of heat shock protein 70 (Hspa8 and active SREBP1. Plasma AST and ALT levels were increased at PND70. These results suggest that transplacental arsenic exposure alters developmental programming in fetal liver, leading to an enduring stress and proinflammatory response postnatally that may contribute to early onset of atherosclerosis. Genes

  17. SELECTIVE-INHIBITION OF REPAIR OF ACTIVE GENES BY HYPERTHERMIA IS DUE TO INHIBITION OF GLOBAL AND TRANSCRIPTION COUPLED REPAIR PATHWAYS

    NARCIS (Netherlands)

    SAKKERS, RJ; FILON, AR; BRUNSTING, JF; KAMPINGA, HH; KONINGS, AWT; MULLENDERS, LHF

    Hyperthermia specifically inhibits the repair of UV-induced DNA photolesions in transcriptionally active genes, To define more precisely which mechanisms underlie the heat-induced inhibition of repair of active genes, removal of cyclobutane pyrimidine dimers (CPDs) was studied in human fibroblasts

  18. Metagenomic Approach Reveals Variation of Microbes with Arsenic and Antimony Metabolism Genes from Highly Contaminated Soil

    Science.gov (United States)

    Luo, Jinming; Bai, Yaohui; Liang, Jinsong; Qu, Jiuhui

    2014-01-01

    Microbes have great potential for arsenic (As) and antimony (Sb) bioremediation in heavily contaminated soil because they have the ability to biotransform As and Sb to species that have less toxicity or are more easily removed. In this study, we integrated a metagenomic method with physicochemical characterization to elucidate the composition of microbial community and functional genes (related to As and Sb) in a high As (range from 34.11 to 821.23 mg kg−1) and Sb (range from 226.67 to 3923.07 mg kg−1) contaminated mine field. Metagenomic analysis revealed that microbes from 18 phyla were present in the 5 samples of soil contaminated with high As and Sb. Moreover, redundancy analysis (RDA) of the relationship between the 18 phyla and the concentration of As and Sb demonstrated that 5 phyla of microbes, i.e. Actinobacteria, Firmicutes, Nitrospirae, Tenericutes and Gemmatimonadetes were positively correlated with As and Sb concentration. The distribution, diversity and abundance of functional genes (including arsC, arrA, aioA, arsB and ACR3) were much higher for the samples containing higher As and Sb concentrations. Based on correlation analysis, the results showed a positive relationship between arsC-like (R2 = 0.871) and aioA-like (R2 = 0.675) gene abundance and As concentration, and indicated that intracellular As(V) reduction and As(III) oxidation could be the dominant As detoxification mechanism enabling the microbes to survive in the environment. This study provides a direct and reliable reference on the diversity of microbial community and functional genes in an extremely high concentration As- and Sb-contaminated environment. PMID:25299175

  19. Arsenic as an endocrine disruptor: effects of arsenic on estrogen receptor-mediated gene expression in vivo and in cell culture.

    Science.gov (United States)

    Davey, Jennifer C; Bodwell, Jack E; Gosse, Julie A; Hamilton, Joshua W

    2007-07-01

    Arsenic (As) contamination of drinking water is considered a serious worldwide environmental health threat that is associated with increased disease risks including skin, lung, bladder, and other cancers; type 2 diabetes; vascular and cardiovascular diseases; reproductive and developmental effects; and neurological and cognitive effects. Increased health risks may occur at as low as 10-50 ppb, while biological effects have been observed in experimental animal and cell culture systems at much lower levels. We previously reported that As is a potent endocrine disruptor, altering gene regulation by the closely related glucocorticoid, mineralocorticoid, progesterone, and androgen steroid receptors (SRs) at concentrations as low as 0.01 microM ( approximately 0.7 ppb). Very low doses enhanced hormone-mediated gene transcription, whereas slightly higher but still noncytotoxic doses were suppressive. We report here that As also disrupts the more distally related estrogen receptor (ER) both in vivo and in cell culture. At noncytotoxic doses (1-50 micromol/kg arsenite) As strongly suppressed ER-dependent gene transcription of the 17beta-estradiol (E2)-inducible vitellogenin II gene in chick embryo liver in vivo. In cell culture, noncytotoxic levels (0.25-3 microM, approximately 20-225 ppb) of As significantly inhibited E2-mediated gene activation of an ER-regulated reporter gene and the native ER-regulated GREB1 gene in human breast cancer MCF-7 cells. While the effects of As on ER-dependent gene regulation were generally similar to As effects on the other SRs, there were specific differences, particularly the lack of significant enhancement at the lowest doses, that may provide insights into possible mechanisms.

  20. Serum homocysteine, arsenic methylation, and arsenic-induced skin lesion incidence in Bangladesh: A one-carbon metabolism candidate gene study.

    Science.gov (United States)

    Niedzwiecki, Megan M; Liu, Xinhua; Zhu, Huiping; Hall, Megan N; Slavkovich, Vesna; Ilievski, Vesna; Levy, Diane; Siddique, Abu B; Kibriya, Muhammad G; Parvez, Faruque; Islam, Tariqul; Ahmed, Alauddin; Navas-Acien, Ana; Graziano, Joseph H; Finnell, Richard H; Ahsan, Habibul; Gamble, Mary V

    2018-02-02

    Inorganic arsenic (As) is methylated via one carbon metabolism (OCM) to mono- and dimethylated arsenicals (MMA and DMA), facilitating urinary excretion. Hyperhomocysteinemia (HHcys), a marker of impaired OCM, is a risk factor for As-induced skin lesions, but the influences of single nucleotide polymorphisms (SNPs) in OCM genes on Hcys, As metabolism and skin lesion risk is unclear. To (i) explore genetic sources of Hcys and the causal role of HHcys in As-induced skin lesion development using OCM genetic proxies for HHcys and (ii) identify OCM SNPs associated with urinary As metabolite proportions and/or skin lesion incidence. We conducted a case-control study nested in the Health Effects of Arsenic Longitudinal Study (HEALS) in Bangladesh which 876 incident skin lesion cases were matched to controls on sex, age, and follow-up time. We measured serum Hcys, urinary As metabolites, and 26 SNPs in 13 OCM genes. Serum Hcys and urinary %DMA were independently associated with increased and decreased odds of skin lesions, respectively. The T allele of MTHFR 677 C ➔ T (rs1801133) was associated with HHcys, higher %MMA, and lower %DMA, but not with skin lesions. Interactions between SNPs and water As on skin lesion risk were suggestive for three variants: the G allele of MTRR rs1801394 and T allele of FOLR1 rs1540087 were associated with lower odds of skin lesions with lower As (≤50 μg/L), and the T allele of TYMS rs1001761 was associated with higher odds of skin lesions with higher As. While HHcys and decreased %DMA were associated with increased risk for skin lesions, and MTHFR 677 C ➔ T was a strong predictor of HHcys, MTHFR 677 C ➔ T was not associated with skin lesion risk. Future studies should explore (i) non-OCM and non-genetic determinants of Hcys and (ii) if genetic findings are replicated in other As-exposed populations, mechanisms by which OCM SNPs may influence the dose-dependent effects of As on skin lesion risk. Copyright © 2018

  1. Structure and expression of the excision repair gene ERCC6, involved in the human disorder Cockayne's syndrome group B.

    NARCIS (Netherlands)

    C. Troelstra (Christine); W. Hesen; D. Bootsma (Dirk); J.H.J. Hoeijmakers (Jan)

    1993-01-01

    textabstractThe human repair gene ERCC6--a presumed DNA (or RNA) helicase--has recently been found to function specifically in preferential nucleotide excision repair (NER). This NER subpathway is primarily directed towards repair of (the transcribed strand of) active genes. Mutations in the ERCC6

  2. [Interaction of the HSM3 gene with genes initiating homologous recombination repair in yeast Saccharomyces cerevisiae].

    Science.gov (United States)

    Chernenkov, A Iu; Fedorov, D V; Gracheva, L M; Evstukhina, T A; Koval'tsova, S V; Peshekhonov, V T; Fedorova, I V; Korolev, V G

    2012-03-01

    It was assumed previously that the mutator phenotype of the hms3 mutant was determined by processes taking place in the D-loop. As a next step, genetic analysis was performed to study the interactions between the hsm3 mutation and mutations of the genes that control the initial steps of the D-loop formation. The mutations of the MMS4 and XRS2 genes, which initiate the double-strand break formation and subsequent repair, were shown to completely block HSM3-dependent UV-induced mutagenesis. Mutations of the RAD51, RAD52, and RAD54 genes, which are also involved in the D-loop formation, only slightly decreased the level of UV-induced mutagenesis in the hsm3 mutant. Similar results were observed for the interaction of hsm3 with the mph1 mutation, which stabilizes the D-loop. In contrast, the shu1 mutation, which destabilizes the D-loop structure, led to an extremely high level of UV-induced mutagenesis and displayed epistatic interactions with the hsm3 mutation. The results made it possible to assume that the hsm3 mutation destabilizes the D-loop, which is a key substrate of both Rad5- and Rad52-dependent postreplicative repair pathways.

  3. DNA Repair Gene Polymorphisms in Hereditary and Sporadic Breast Cancer

    National Research Council Canada - National Science Library

    Ricks-Santi, Luisel

    2006-01-01

    .... There is variable penetrance for breast cancer among women in families with known BRCA1 mutations, and we hypothesize that this might be due to genetic variants in wild-type BRCA1 or other DNA repair...

  4. Genomic survey and expression analysis of DNA repair genes in the genus Leptospira.

    Science.gov (United States)

    Martins-Pinheiro, Marinalva; Schons-Fonseca, Luciane; da Silva, Josefa B; Domingos, Renan H; Momo, Leonardo Hiroyuki Santos; Simões, Ana Carolina Quirino; Ho, Paulo Lee; da Costa, Renata M A

    2016-04-01

    Leptospirosis is an emerging zoonosis with important economic and public health consequences and is caused by pathogenic leptospires. The genus Leptospira belongs to the order Spirochaetales and comprises saprophytic (L. biflexa), pathogenic (L. interrogans) and host-dependent (L. borgpetersenii) members. Here, we present an in silico search for DNA repair pathways in Leptospira spp. The relevance of such DNA repair pathways was assessed through the identification of mRNA levels of some genes during infection in animal model and after exposition to spleen cells. The search was performed by comparison of available Leptospira spp. genomes in public databases with known DNA repair-related genes. Leptospires exhibit some distinct and unexpected characteristics, for instance the existence of a redundant mechanism for repairing a chemically diverse spectrum of alkylated nucleobases, a new mutS-like gene and a new shorter version of uvrD. Leptospira spp. shares some characteristics from Gram-positive, as the presence of PcrA, two RecQ paralogs and two SSB proteins; the latter is considered a feature shared by naturally competent bacteria. We did not find a significant reduction in the number of DNA repair-related genes in both pathogenic and host-dependent species. Pathogenic leptospires were enriched for genes dedicated to base excision repair and non-homologous end joining. Their evolutionary history reveals a remarkable importance of lateral gene transfer events for the evolution of the genus. Up-regulation of specific DNA repair genes, including components of SOS regulon, during infection in animal model validates the critical role of DNA repair mechanisms for the complex interplay between host/pathogen.

  5. Transcript RNA supports precise repair of its own DNA gene.

    Science.gov (United States)

    Keskin, Havva; Meers, Chance; Storici, Francesca

    2016-01-01

    The transfer of genetic information from RNA to DNA is considered an extraordinary process in molecular biology. Despite the fact that cells transcribe abundant amount of RNA with a wide range of functions, it has been difficult to uncover whether RNA can serve as a template for DNA repair and recombination. An increasing number of experimental evidences suggest a direct role of RNA in DNA modification. Recently, we demonstrated that endogenous transcript RNA can serve as a template to repair a DNA double-strand break (DSB), the most harmful DNA lesion, not only indirectly via formation of a DNA copy (cDNA) intermediate, but also directly in a homology driven mechanism in budding yeast. These results point out that the transfer of genetic information from RNA to DNA is more general than previously thought. We found that transcript RNA is more efficient in repairing a DSB in its own DNA (in cis) than in a homologous but ectopic locus (in trans). Here, we summarize current knowledge about the process of RNA-driven DNA repair and recombination, and provide further data in support of our model of DSB repair by transcript RNA in cis. We show that a DSB is precisely repaired predominately by transcript RNA and not by residual cDNA in conditions in which formation of cDNA by reverse transcription is inhibited. Additionally, we demonstrate that defects in ribonuclease (RNase) H stimulate precise DSB repair by homologous RNA or cDNA sequence, and not by homologous DNA sequence carried on a plasmid. These results highlight an antagonistic role of RNase H in RNA-DNA recombination. Ultimately, we discuss several questions that should be addressed to better understand mechanisms and implications of RNA-templated DNA repair and recombination.

  6. Metagenomic profiles and antibiotic resistance genes in gut microbiota of mice exposed to arsenic and iron.

    Science.gov (United States)

    Guo, Xuechao; Liu, Su; Wang, Zhu; Zhang, Xu-xiang; Li, Mei; Wu, Bing

    2014-10-01

    Iron (Fe) has been widely applied to treat arsenic (As)-contaminated water, and Fe could influence bioavailability and toxicity of As. However, little is known about the impact of As and/or Fe on gut microbiota, which plays important roles in host health. In this study, high-throughput sequencing and quantitative real time PCR were applied to analyze the impact of As and Fe on mouse gut microbiota. Co-exposure of As and Fe mitigated effects on microbial community to a certain extent. Correlation analysis showed the shifts in gut microbiota caused by As and/or Fe exposure might be important reason of changes in metabolic profiles of mouse. For antibiotic resistance genes (ARGs), co-exposure of As and Fe increased types and abundance of ARGs. But for high abundance ARGs, such as tetQ, tetO and tetM, co-exposure of As and Fe mitigated effects on their abundances compared to exposure to As and Fe alone. No obvious relationship between ARGs and mobile genetic elements were found. The changes in ARGs caused by metal exposure might be due to the alteration of gut microbial diversity. Our results show that changes of gut microbial community caused by As and/or Fe can influence host metabolisms and abundances of ARGs in gut, indicating that changes of gut microbiota should be considered during the risk assessment of As and/or Fe. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Arsenic trioxide impairs spermatogenesis via reducing gene expression levels in testosterone synthesis pathway.

    Science.gov (United States)

    Chiou, Tzeon-Jye; Chu, Sin-Tak; Tzeng, Woan-Fang; Huang, Yu-Chen; Liao, Chi-Jr

    2008-08-01

    Arsenic trioxide (As2O3) has recently received a great deal of attention because of its capacity to cause complete remission of acute promyelocytic leukemia (APL). To evaluate possible toxicity on the male reproductive system during arsenic therapy, male mice were used as a model. Outbred mice (ICR/CD1 and S-W, 6 weeks old) were subcutaneously administered As2O3 continuously for 5 days, with a 2-day interval, for a period of 3 weeks. As2O3 doses were 0, 0.15, 0.3, 1.5, and 3.0 mg/kg of body weight, respectively. No mice died in any dosage group. Our data showed no significant changes in food consumption or in the weight of the body, liver, testis, or epididymis after As2O3 treatment. Using histological observation to identify the stages of seminiferous tubules, we showed that As2O3 treatment resulted in the inhibition of spermatogenesis. The frequency of mature seminiferous tubules (stages VII and VIII) was markedly decreased after As2O3 treatment. A significant decrease in sperm motility and viability also was found with computer-assisted sperm analysis (CASA) and a SYBR14/PI staining assay. Using an enzyme-linked immunosorbent assay (ELISA), we found a significant decrease in levels of plasma luteinizing hormone (LH) at a dose of 3.0 mg/kg body weight. No significant difference was found in plasma follicle-stimulating hormone (FSH) in all dosages. A significant decrease was found in plasma testosterone in all dosages, but no difference in intratesticular testosterone, with the exception of As2O3 at a dose of 3.0 mg/kg body weight. Moreover, there was a significant decrease in the levels of mRNA involved in testicular testosterone synthesis, cytochrome P450 side chain cleavage (P450scc), 3beta-hydroxysteroid dehydrogenase (3beta-HSD), and cytochrome P450 17-alpha hydroxylase/C17-20 lyase (Cyp17). The use of immunohistological observation showed no obvious difference in the testosterone level of Leydig cells of mice treated with As2O3 at doses of 0.3 and 1.5 mg

  8. Genome analysis of DNA repair genes in the alpha proteobacterium Caulobacter crescentus

    Directory of Open Access Journals (Sweden)

    Menck Carlos FM

    2007-03-01

    Full Text Available Abstract Background The integrity of DNA molecules is fundamental for maintaining life. The DNA repair proteins protect organisms against genetic damage, by removal of DNA lesions or helping to tolerate them. DNA repair genes are best known from the gamma-proteobacterium Escherichia coli, which is the most understood bacterial model. However, genome sequencing raises questions regarding uniformity and ubiquity of these DNA repair genes and pathways, reinforcing the need for identifying genes and proteins, which may respond to DNA damage in other bacteria. Results In this study, we employed a bioinformatic approach, to analyse and describe the open reading frames potentially related to DNA repair from the genome of the alpha-proteobacterium Caulobacter crescentus. This was performed by comparison with known DNA repair related genes found in public databases. As expected, although C. crescentus and E. coli bacteria belong to separate phylogenetic groups, many of their DNA repair genes are very similar. However, some important DNA repair genes are absent in the C. crescentus genome and other interesting functionally related gene duplications are present, which do not occur in E. coli. These include DNA ligases, exonuclease III (xthA, endonuclease III (nth, O6-methylguanine-DNA methyltransferase (ada gene, photolyase-like genes, and uracil-DNA-glycosylases. On the other hand, the genes imuA and imuB, which are involved in DNA damage induced mutagenesis, have recently been described in C. crescentus, but are absent in E. coli. Particularly interesting are the potential atypical phylogeny of one of the photolyase genes in alpha-proteobacteria, indicating an origin by horizontal transfer, and the duplication of the Ada orthologs, which have diverse structural configurations, including one that is still unique for C. crescentus. Conclusion The absence and the presence of certain genes are discussed and predictions are made considering the particular

  9. Germline mutations in DNA repair genes may predict neoadjuvant therapy response in triple negative breast patients.

    Science.gov (United States)

    Spugnesi, Laura; Gabriele, Michele; Scarpitta, Rosa; Tancredi, Mariella; Maresca, Luisa; Gambino, Gaetana; Collavoli, Anita; Aretini, Paolo; Bertolini, Ilaria; Salvadori, Barbara; Landucci, Elisabetta; Fontana, Andrea; Rossetti, Elena; Roncella, Manuela; Naccarato, Giuseppe Antonio; Caligo, Maria Adelaide

    2016-12-01

    Triple negative breast cancers (TNBCs) represent about 15-20% of all breast cancer cases and are characterized by a complex molecular heterogeneity. Some TNBCs exhibit clinical and pathological properties similar to BRCA-mutated tumors, without actually bearing a mutation in BRCA genes. This "BRCAness" phenotype may be explained by germline mutations in other genes involved in DNA repair. Although respond to chemotherapy with alkylating agents, they have a high risk of recurrence and progression. Some studies have shown the efficacy of neoadjuvant therapy in TNBC patients with DNA repair defects, but proper biomarkers of DNA repair deficiency are still needed. Here, we investigated if mutations in DNA repair genes may be correlated with anthracyclines/taxanes neoadjuvant therapy response. DNA from 19 TNBC patients undergoing neoadjuvant therapy were subjected to next generation sequencing of a panel of 24 genes in DNA repair and breast cancer predisposition. In this study, 5 of 19 patients (26%) carried a pathogenic mutation in BRCA1, PALB2, RAD51C and two patients carried a probable pathogenic missense variant. Moreover, VUS (Variants of Unknown Significance) in other genes, predicted to be deleterious by in silico tools, were detected in five patients. Germline mutations in DNA repair genes were found to be associated with the group of TNBC patients who responded to therapy. We conclude that a subgroup of TNBC patients have defects in DNA repair genes, other than BRCA1, and such patients respond favourably to neoadjuvant anthracyclines/taxanes therapy. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. Assignment of ten DNA repair genes from Schizosaccharomyces pombe to chromosomal NotI restriction fragments

    NARCIS (Netherlands)

    B.C. Broughton; N.C. Barbet; J. Murray (Johanne); F.Z. Watts (Felicity); M.H.M. Koken (Marcel); A.R. Lehmann (Alan); A.M. Carr (Anthony)

    1991-01-01

    textabstractTen DNA repair (rad) genes from the fission yeast, Schizosaccharomyces pombe were mapped to the 17 NotI fragments of the three chromosomes. Nine of the genes map to chromosome I, but there is no evidence for significant clustering.

  11. Association of DNA repair gene XRCC1 and lung cancer susceptibility among nonsmoking Chinese women

    DEFF Research Database (Denmark)

    Yin, J.; Vogel, Ulla Birgitte; Ma, Y.

    2009-01-01

    Nonsmokers who develop lung cancer provide a good model for investigating the effect of genetic polymorphisms. XRCC1 is one of the major DNA repair proteins involved in the base-excision repair pathway. XRCC1 gene variations may lead to lower DNA repair capacity and thus confer inherited predispo......Nonsmokers who develop lung cancer provide a good model for investigating the effect of genetic polymorphisms. XRCC1 is one of the major DNA repair proteins involved in the base-excision repair pathway. XRCC1 gene variations may lead to lower DNA repair capacity and thus confer inherited...... predisposition to cancer risk. To address this question in more detail, we conducted a hospital-based case-control study consisting of 55 lung cancer cases and 74 cancer-free controls matched on age and ethnicity among nonsmoking Chinese women. We analyzed five coding single-nucleotide polymorphisms in the XRCC1...... gene: Agr194Trp, Arg280His, Arg399Gln, Pro206Pro, and Gln632Gln. Polymerase chain reaction-restriction fragment length polymorphism was used for genotyping. Carriers of the variant T-allele of Arg194Trp had a lower lung cancer risk than carriers of CC genotypes [odds ratio (OR)=0.46, 95% confidence...

  12. Expression signatures of DNA repair genes correlate with survival prognosis of astrocytoma patients.

    Science.gov (United States)

    de Sousa, Juliana Ferreira; Torrieri, Raul; Serafim, Rodolfo Bortolozo; Di Cristofaro, Luis Fernando Macedo; Escanfella, Fábio Dalbon; Ribeiro, Rodrigo; Zanette, Dalila Lucíola; Paçó-Larson, Maria Luisa; da Silva, Wilson Araujo; Tirapelli, Daniela Pretti da Cunha; Neder, Luciano; Carlotti, Carlos Gilberto; Valente, Valeria

    2017-04-01

    Astrocytomas are the most common primary brain tumors. They are very resistant to therapies and usually progress rapidly to high-grade lesions. Here, we investigated the potential role of DNA repair genes in astrocytoma progression and resistance. To this aim, we performed a polymerase chain reaction array-based analysis focused on DNA repair genes and searched for correlations between expression patters and survival prognoses. We found 19 genes significantly altered. Combining these genes in all possible arrangements, we found 421 expression signatures strongly associated with poor survival. Importantly, five genes (DDB2, EXO1, NEIL3, BRCA2, and BRIP1) were independently correlated with worse prognoses, revealing single-gene signatures. Moreover, silencing of EXO1, which is remarkably overexpressed, promoted faster restoration of double-strand breaks, while NEIL3 knockdown, also highly overexpressed, caused an increment in DNA damage and cell death after irradiation of glioblastoma cells. These results disclose the importance of DNA repair pathways for the maintenance of genomic stability of high-grade astrocytomas and suggest that EXO1 and NEIL3 overexpression confers more efficiency for double-strand break repair and resistance to reactive oxygen species, respectively. Thereby, we highlight these two genes as potentially related with tumor aggressiveness and promising candidates as novel therapeutic targets.

  13. Pan-cancer analysis of bi-allelic alterations in homologous recombination DNA repair genes.

    Science.gov (United States)

    Riaz, Nadeem; Blecua, Pedro; Lim, Raymond S; Shen, Ronglai; Higginson, Daniel S; Weinhold, Nils; Norton, Larry; Weigelt, Britta; Powell, Simon N; Reis-Filho, Jorge S

    2017-10-11

    BRCA1 and BRCA2 are involved in homologous recombination (HR) DNA repair and are germ-line cancer pre-disposition genes that result in a syndrome of hereditary breast and ovarian cancer (HBOC). Whether germ-line or somatic alterations in these genes or other members of the HR pathway and if mono- or bi-allelic alterations of HR-related genes have a phenotypic impact on other cancers remains to be fully elucidated. Here, we perform a pan-cancer analysis of The Cancer Genome Atlas (TCGA) data set and observe that bi-allelic pathogenic alterations in homologous recombination (HR) DNA repair-related genes are prevalent across many malignancies. These bi-allelic alterations often associate with genomic features of HR deficiency. Further, in ovarian, breast and prostate cancers, bi-allelic alterations are mutually exclusive of each other. The combination of these two properties facilitates reclassification of variants of unknown significance affecting DNA repair genes, and may help personalize HR directed therapies in the clinic.Germline mutations in homologous recombination (HR) DNA repair genes are linked to breast and ovarian cancer. Here, the authors show that mutually exclusive bi-allelic inactivation of HR genes are present in other cancer types and associated with genomic features of HR deficiency, expanding the potential use of HR-directed therapies.

  14. A human repair gene ERCC5 is involved in group G xeroderma pigmentosum

    Energy Technology Data Exchange (ETDEWEB)

    Shiomi, Tadahiro [National Inst. of Radiological Sciences, Chiba (Japan)

    1994-03-01

    In E. coli, ultraviolet-induced DNA damage is removed by the coordinated action of UVR A, B, C, and D proteins (1). In Saccharomyces cerevisiae, more than ten genes have been reported to be involved in excision repair (2). The nucleotide excision repair pathway has been extensively studied in these organisms. To facilitate studying nucleotide excision repair in mammalian cells. Ultraviolet-sensitive rodent cell mutants have been isolated and classified into 11 complementation groups (9,10). The human nucleotide excision repair genes which complement the defects of the mutants have been designated as the ERCC (excision repair cross-complementing) genes; a number is added to refer to the particular rodent complementation group that is corrected by the gene. Recently, several human DNA repair genes have been cloned using rodent cell lines sensitive to ultraviolet. These include ERCC2 (3), ERCC3 (4), and ERCC6 (5), which correspond to the defective genes in the ultraviolet-sensitive human disorders xeroderma pigmentosum (XP) group D (6) and group B (4), and Cockayne`s syndrome (CS) group B (7), respectively. The human excision repair gene ERCC5 was cloned after DNA-mediated gene transfer of human HeLa cell genomic DNA into the ultraviolet-sensitive mouse mutant XL216, a member of rodent complementation group 5 (11,12) and the gene was mapped on human chromosome 13q32.3-q33.1 by the replication R-banding fluorescence in situ hybridization method (13). The ERCC5 cDNA encodes a predicted 133 kDa nuclear protein that shares some homology with product of the yeast DNA repair gene RAD 2. Transfection with mouse ERCC5 cDNA restored normal levels of ultraviolet-resistance to XL216 cells. Microinjection of ERCC5 cDNA specifically restored the defect of XP group G cells (XP-G) as measured by unscheduled DNA synthesis (UDS), and XP-G cells stably transformed with ERCC5 cDNA showed nearly normal ultraviolet resistance. (J.P.N.).

  15. Genetic variants of the DNA repair genes from Exome Aggregation Consortium (EXAC) database: significance in cancer.

    Science.gov (United States)

    Das, Raima; Ghosh, Sankar Kumar

    2017-04-01

    DNA repair pathway is a primary defense system that eliminates wide varieties of DNA damage. Any deficiencies in them are likely to cause the chromosomal instability that leads to cell malfunctioning and tumorigenesis. Genetic polymorphisms in DNA repair genes have demonstrated a significant association with cancer risk. Our study attempts to give a glimpse of the overall scenario of the germline polymorphisms in the DNA repair genes by taking into account of the Exome Aggregation Consortium (ExAC) database as well as the Human Gene Mutation Database (HGMD) for evaluating the disease link, particularly in cancer. It has been found that ExAC DNA repair dataset (which consists of 228 DNA repair genes) comprises 30.4% missense, 12.5% dbSNP reported and 3.2% ClinVar significant variants. 27% of all the missense variants has the deleterious SIFT score of 0.00 and 6% variants carrying the most damaging Polyphen-2 score of 1.00, thus affecting the protein structure and function. However, as per HGMD, only a fraction (1.2%) of ExAC DNA repair variants was found to be cancer-related, indicating remaining variants reported in both the databases to be further analyzed. This, in turn, may provide an increased spectrum of the reported cancer linked variants in the DNA repair genes present in ExAC database. Moreover, further in silico functional assay of the identified vital cancer-associated variants, which is essential to get their actual biological significance, may shed some lights in the field of targeted drug development in near future. Copyright © 2017. Published by Elsevier B.V.

  16. Analysis of gene repair tracts from Cas9/gRNA double-stranded breaks in the human CFTR gene

    OpenAIRE

    Hollywood, Jennifer A.; Lee, Ciaran M.; Scallan, Martina F.; Harrison, Patrick T.

    2016-01-01

    To maximise the efficiency of template-dependent gene editing, most studies describe programmable and/or RNA-guided endonucleases that make a double-stranded break at, or close to, the target sequence to be modified. The rationale for this design strategy is that most gene repair tracts will be very short. Here, we describe a CRISPR Cas9/gRNA selection-free strategy which uses deep sequencing to characterise repair tracts from a donor plasmid containing seven nucleotide differences across a 2...

  17. Approaches to diagnose DNA mismatch repair gene defects in cancer

    DEFF Research Database (Denmark)

    Peña-Diaz, Javier; Rasmussen, Lene Juel

    2016-01-01

    genes also renders cells resistant to some chemotherapeutic agents. Therefore, diagnosis of MMR deficiency has important implications for the management of the patients, the surveillance of their relatives in the case of LS and for the choice of treatment. Some of the alterations found in MMR genes have...... genes and anticipates the need of diagnostic tools for rapid assessment of their pathogenicity. This review describes current tools and future strategies for addressing the relevance of MMR gene alterations in human disease....

  18. Polymorphism of inflammatory genes and arsenic methylation capacity are associated with urothelial carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Chia-Chang [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Department of Urology, Taipei Medical University—Shuang Ho Hospital, Taipei, Taiwan (China); Huang, Yung-Kai [School of Oral Hygiene, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan (China); Chung, Chi-Jung [Department of Health Risk Management, College of Public Health, China Medical University and Hospital, Taichung, Taiwan (China); Department of Medical Research, China Medical University Hospital, Taichung, Taiwan (China); Huang, Chao-Yuan; Pu, Yeong-Shiau [Department of Urology, National Taiwan University Hospital, College of Medicine National Taiwan University, Taipei, Taiwan (China); Shiue, Horng-Sheng [Department of Chinese Medicine, Chang Gung Memorial Hospital, Taipei, Taiwan (China); Lai, Li-An [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Lin, Ying-Chin [Department of Family Medicine, Shung Ho Hospital, Taipei Medical University, Taipei, Taiwan (China); Department of Health Examination, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan (China); Su, Chien-Tien [Department of Family Medicine, Taipei Medical University Hospital, Taipei, Taiwan (China); Hsueh, Yu-Mei, E-mail: ymhsueh@tmu.edu.tw [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China)

    2013-10-01

    Chronic exposure to arsenic can generate reactive oxidative species, which can induce certain proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-8 (IL-8). TNF-α, IL-6 and IL-8 have been shown to be involved in the development and progression of various cancers, including bladder cancer. This study aimed to investigate the joint effect of the polymorphism of TNF-α − 308 G/A, IL-6 − 174 G/C, IL-8 − 251 T/A and urinary arsenic profiles on urothelial carcinoma (UC) risk. This study evaluated 300 pathologically-confirmed cases of UC and 594 cancer-free controls. Urinary arsenic species were detected using high-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. The polymorphism of TNF-α − 308 G/A, IL-6 − 174 G/C and IL-8 − 251 T/A was determined using polymerase chain reaction-restriction fragment length polymorphism. The joint effects on UC risk were estimated by odds ratios and 95% confidence intervals using unconditional logistic regression. We found that the TNF-α − 308 A/A and IL-8 − 251 T/T polymorphisms were significantly associated with UC. Moreover, significant dose–response joint effect of TNF-α − 308 A/A or IL-8 − 251 T/T genotypes and arsenic methylation indices were seen to affect UC risk. The present results also showed a significant increase in UC risk in subjects with the IL-8 − 251 T/T genotype for each SD increase in urinary total arsenic and MMA%. In contrast, a significant decrease in UC risk was found in subjects who carried the IL-8 − 251 T/T genotype for each SD increase in DMA%. - Highlights: • Joint effect of the TNF-α -308 A/A genotype and urinary total arsenic affected UC. • Joint effect of the IL-8 -251 T/T genotype and urinary total arsenic affected UC. • Urinary total arsenic level, TNF-α -308 A/A and IL-8 -251 T/T genotype affected UC.

  19. Arsenic Detoxification by Geobacter Species.

    Science.gov (United States)

    Dang, Yan; Walker, David J F; Vautour, Kaitlin E; Dixon, Steven; Holmes, Dawn E

    2017-02-15

    Insight into the mechanisms for arsenic detoxification by Geobacter species is expected to improve the understanding of global cycling of arsenic in iron-rich subsurface sedimentary environments. Analysis of 14 different Geobacter genomes showed that all of these species have genes coding for an arsenic detoxification system (ars operon), and several have genes required for arsenic respiration (arr operon) and methylation (arsM). Genes encoding four arsenic repressor-like proteins were detected in the genome of G. sulfurreducens; however, only one (ArsR1) regulated transcription of the ars operon. Elimination of arsR1 from the G. sulfurreducens chromosome resulted in enhanced transcription of genes coding for the arsenic efflux pump (Acr3) and arsenate reductase (ArsC). When the gene coding for Acr3 was deleted, cells were not able to grow in the presence of either the oxidized or reduced form of arsenic, while arsC deletion mutants could grow in the presence of arsenite but not arsenate. These studies shed light on how Geobacter influences arsenic mobility in anoxic sediments and may help us develop methods to remediate arsenic contamination in the subsurface. This study examines arsenic transformation mechanisms utilized by Geobacter, a genus of iron-reducing bacteria that are predominant in many anoxic iron-rich subsurface environments. Geobacter species play a major role in microbially mediated arsenic release from metal hydroxides in the subsurface. This release raises arsenic concentrations in drinking water to levels that are high enough to cause major health problems. Therefore, information obtained from studies of Geobacter should shed light on arsenic cycling in iron-rich subsurface sedimentary environments, which may help reduce arsenic-associated illnesses. These studies should also help in the development of biosensors that can be used to detect arsenic contaminants in anoxic subsurface environments. We examined 14 different Geobacter genomes and found

  20. Prevalence and prognostic role of mismatch repair gene defect in endometrial cancer patients.

    Science.gov (United States)

    Tangjitgamol, Siriwan; Kittisiam, Thannaporn; Tanvanich, Sujitra

    2017-09-01

    The study was to evaluate the prevalence of mismatch repair gene defect among Thai patients with endometrial cancer and its association with clinico-pathological features and survivals. The formalin fixed paraffin-embedded blocks of EMC tissue from hysterectomy specimens of patients having surgery in our institution between 1 Jan 1995 and 31 December 2016 were assessed for the immunohistochemical expression of 4 mismatch repair proteins (MLH1, PMS, MSH2, MSH 6). Mismatch repair gene defect was determined by a negative expression of at least 1 protein. Among 385 EMC patients included in the study, mean age was 57.3 ± 10.8 years with 62.3% aged ⩽ 60 years. The most frequent mismatch repair gene defect was MSH6 (38.7%), followed by PMS2 (34.3%), MLH1 (33.2%), and MSH2 (16.4%). Overall, 55.1% showed negative expression of at least one protein. We found significantly higher mismatch repair gene defect in patients aged ⩽ 60 years, with early stage disease, and negative lymph node status than the other comparative groups: 59.2% vs 48.3% for age (p = 0.037), 58.2% vs 45.2% (p = 0.027) for stage, and 58.1% vs 44.6% (p = 0.048) for nodal status. The 5-year progression-free survival, overall survival, and endometrial cancer-specific survival of patients with mismatch repair gene defect was higher than those without gene defect. The differences were statistically significant for only progression-free survival and endometrial cancer-specific survival: 87.7% (95% confidence interval = 83.0%-92.4%) vs 81.5% (95% confidence interval = 75.4%-87.6%) (p = 0.049) for progression-free survival and 91.0% (95% confidence interval = 86.9%-95.1%) vs 85.5% (95% confidence interval = 80.0%-91.0%) (p = 0.044) for endometrial cancer-specific survival, respectively. In conclusion, more than half of Thai endometrial cancer patients had mismatch repair gene defect. The patients with mismatch repair gene defect had significantly younger age (⩽ 60 years) and better prognosis in terms of

  1. The Association of Low-Penetrance Variants in DNA Repair Genes with Colorectal Cancer: A Systematic Review and Meta-Analysis

    OpenAIRE

    Aggarwal, Nikhil; Donald, Neil D; Malik, Salim; Selvendran, Subothini S; McPhail, Mark JW.; Monahan, Kevin J

    2017-01-01

    Objectives: Approximately 35% of colorectal cancer (CRC) risk is attributable to heritable factors known hereditary syndromes, accounting for 6%. The remainder may be due to lower penetrance polymorphisms particularly of DNA repair genes. DNA repair pathways, including base excision repair (BER), nucleotide excision repair (NER), mismatch repair (MMR), direct reversal repair (DRR), and double-strand break repair are complex, evolutionarily conserved, and critical in carcinogenesis. Germline m...

  2. Effects of arsenic exposure from drinking water on spatial memory, ultra-structures and NMDAR gene expression of hippocampus in rats.

    Science.gov (United States)

    Luo, Jiao-hua; Qiu, Zhi-qun; Shu, Wei-qun; Zhang, Yong-yan; Zhang, Liang; Chen, Ji-an

    2009-01-30

    Epidemiological investigations indicate that chronic arsenic exposure can damage neurobehavioral function in children. The present study was aimed to study the effects of arsenic exposure from drinking water on the spatial memory, and hippocampal ultra-structures and N-methyl-d-aspartate receptor (NMDAR) gene expression in rats. Sprague-Dawley rats were assigned to four groups: rats in control group drank regular water, rats in other groups drank water with final arsenic concentration of 2.72 mg/L (group A), 13.6 mg/L (group B) and 68 mg/L (group C), respectively, for 3 months. The levels of arsenic in blood serum and hippocampus were monitored. Rats were tested in Morris water maze (MWM) for memory status. Samples of hippocampus were collected from two rats in each group for transmission electron microscopic study and the detection of NMDAR expression by RT-PCR. The rats in group C showed a significant delay in hidden platform acquisition. Neurons and endothelial cells presented pathological changes and the expression of NR2A was down-regulated in hippocampus in arsenic exposed rats. Our data indicated that arsenic exposure of 68 mg/L caused spatial memory damage, of which the morphological and biochemical bases could be the ultra-structure changes and reduced NR2A expression in hippocampus.

  3. DNA damage and gene therapy of xeroderma pigmentosum, a human DNA repair-deficient disease

    Energy Technology Data Exchange (ETDEWEB)

    Dupuy, Aurélie [Laboratory of Genetic Instability and Oncogenesis UMR8200CNRS, Institut Gustave Roussy and University Paris-Sud, Villejuif (France); Sarasin, Alain, E-mail: alain.sarasin@gustaveroussy.fr [Laboratory of Genetic Instability and Oncogenesis UMR8200CNRS, Institut Gustave Roussy and University Paris-Sud, Villejuif (France); Service de Génétique, Institut Gustave Roussy (France)

    2015-06-15

    Graphical abstract: - Highlights: • Full correction of mutation in the XPC gene by engineered nucleases. • Meganucleases and TALENs are inhibited by 5-MeC for inducing double strand breaks. • Gene therapy of XP cells is possible using homologous recombination for DSB repair. - Abstract: Xeroderma pigmentosum (XP) is a genetic disease characterized by hypersensitivity to ultra-violet and a very high risk of skin cancer induction on exposed body sites. This syndrome is caused by germinal mutations on nucleotide excision repair genes. No cure is available for these patients except a complete protection from all types of UV radiations. We reviewed the various techniques to complement or to correct the genetic defect in XP cells. We, particularly, developed the correction of XP-C skin cells using the fidelity of the homologous recombination pathway during repair of double-strand break (DSB) in the presence of XPC wild type sequences. We used engineered nucleases (meganuclease or TALE nuclease) to induce a DSB located at 90 bp of the mutation to be corrected. Expression of specific TALE nuclease in the presence of a repair matrix containing a long stretch of homologous wild type XPC sequences allowed us a successful gene correction of the original TG deletion found in numerous North African XP patients. Some engineered nucleases are sensitive to epigenetic modifications, such as cytosine methylation. In case of methylated sequences to be corrected, modified nucleases or demethylation of the whole genome should be envisaged. Overall, we showed that specifically-designed TALE-nuclease allowed us to correct a 2 bp deletion in the XPC gene leading to patient's cells proficient for DNA repair and showing normal UV-sensitivity. The corrected gene is still in the same position in the human genome and under the regulation of its physiological promoter. This result is a first step toward gene therapy in XP patients.

  4. Differential expression of genes encoding phosphate transporters contributes to arsenic accumulation in shrub willow (Salix spp.)

    Science.gov (United States)

    Emily E. Puckett; Michelle J. Serpiglia; Alyssa M. DeLeon; Stephanie Long; Rakesh Minocha; Lawrence B. Smart

    2012-01-01

    Studies of arsenate and phosphate uptake by plants in hydroponic and soil systems indicate a common transport mechanism via the phosphate transporters (PHTs) due to structural similarity of the anions. Typically, the presence of phosphate decreases plant uptake and translocation of arsenate in hydroponic solution. This study quantified arsenic (As) uptake related to...

  5. Expression of the sFLT1 gene in cord blood cells is associated to maternal arsenic exposure and decreased birth weight.

    Directory of Open Access Journals (Sweden)

    Sylvie Remy

    Full Text Available There is increasing epidemiologic evidence that arsenic exposure in utero is associated with adverse pregnancy outcomes and may contribute to long-term health effects. These effects may occur at low environmental exposures but the underlying molecular mechanism is not clear. We collected cord blood samples of 183 newborns to identify associations between arsenic levels and birth anthropometric parameters in an area with very low arsenic exposure. Our core research aim was to screen for transcriptional marks that mechanistically explain these associations. Multiple regression analyses showed that birth weight decreased with 47 g (95% CI: 16-78 g for an interquartile range increase of 0.99 μg/L arsenic. The model was adjusted for child's sex, maternal smoking during pregnancy, gestational age, and parity. Higher arsenic concentrations and reduced birth weight were positively associated with changes in expression of the sFLT1 (soluble fms-like tyrosine kinase-1 gene in cord blood cells in girls. The protein product of sFLT1 is a scavenger of vascular endothelial growth factor (VEGF in the extracellular environment and plays a key role in the inhibition of placental angiogenesis. In terms of fetal development, inhibition of placental angiogenesis leads to impaired nutrition and hence to growth retardation. Various genes related to DNA methylation and oxidative stress showed also changed expression in relation to arsenic exposure but were not related to birth outcome parameters. In conclusion, this study suggests that increased expression of sFLT1 is an intermediate marker that points to placental angiogenesis as a pathway linking prenatal arsenic exposure to reduced birth weight.

  6. The effect of cigarette smoke and arsenic exposure on urothelial carcinoma risk is modified by glutathione S-transferase M1 gene null genotype

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Chi-Jung [Department of Health Risk Management, College of Public Health, China Medical University, Taichung, Taiwan (China); Department of Medical Research, China Medical University Hospital, Taichung, Taiwan (China); Huang, Chao-Yuan; Pu, Yeong-Shiau [Department of Urology, National Taiwan University Hospital, Taipei, Taiwan (China); Shiue, Horng-Sheng [Department of Chinese Medicine, Chang Gung Memorial Hospital, Taipei, Taiwan (China); Su, Chien-Tien [Department of Family Medicine, Taipei Medical University Hospital, Taipei, Taiwan (China); Hsueh, Yu-Mei, E-mail: ymhsueh@tmu.edu.tw [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China)

    2013-01-15

    Inter-individual variation in the metabolism of xenobiotics, caused by factors such as cigarette smoking or inorganic arsenic exposure, is hypothesized to be a susceptibility factor for urothelial carcinoma (UC). Therefore, our study aimed to evaluate the role of gene–environment interaction in the carcinogenesis of UC. A hospital-based case–control study was conducted. Urinary arsenic profiles were measured using high-performance liquid chromatography–hydride generator-atomic absorption spectrometry. Genotyping was performed using a polymerase chain reaction-restriction fragment length polymorphism technique. Information about cigarette smoking exposure was acquired from a lifestyle questionnaire. Multivariate logistic regression was applied to estimate the UC risk associated with certain risk factors. We found that UC patients had higher urinary levels of total arsenic, higher percentages of inorganic arsenic (InAs%) and monomethylarsonic acid (MMA%) and lower percentages of dimethylarsinic acid (DMA%) compared to controls. Subjects carrying the GSTM1 null genotype had significantly increased UC risk. However, no association was observed between gene polymorphisms of CYP1A1, EPHX1, SULT1A1 and GSTT1 and UC risk after adjustment for age and sex. Significant gene–environment interactions among urinary arsenic profile, cigarette smoking, and GSTM1 wild/null polymorphism and UC risk were observed after adjustment for potential risk factors. Overall, gene–environment interactions simultaneously played an important role in UC carcinogenesis. In the future, large-scale studies should be conducted using tag-SNPs of xenobiotic-metabolism-related enzymes for gene determination. -- Highlights: ► Subjects with GSTM1 null genotype had significantly increased UC risk. ► UC patients had poor arsenic metabolic ability compared to controls. ► GSTM1 null genotype may modify arsenic related UC risk.

  7. Gene therapy and peripheral nerve repair : a perspective

    NARCIS (Netherlands)

    Hoyng, Stefan A; de Winter, Fred; Tannemaat, Martijn R; Blits, Bas; Malessy, Martijn J A; Verhaagen, J.

    2015-01-01

    Clinical phase I/II studies have demonstrated the safety of gene therapy for a variety of central nervous system disorders, including Canavan's, Parkinson's (PD) and Alzheimer's disease (AD), retinal diseases and pain. The majority of gene therapy studies in the CNS have used adeno-associated viral

  8. Cloning of human and mouse genes homologous to RAD52, a yeast gene involved in DNA repair and recombination.

    NARCIS (Netherlands)

    D.F.R. Muris; O.Y. Bezzubova (Olga); J-M. Buerstedde; K. Vreeken; A.S. Balajee; C.J. Osgood; C. Troelstra (Christine); J.H.J. Hoeijmakers (Jan); K. Ostermann; H. Schmidt (Henning); A.T. Natarajan; J.C.J. Eeken; P.H.M. Lohmann (Paul); A. Pastink (Albert)

    1994-01-01

    textabstractThe RAD52 gene of Saccharomyces cerevisiae is required for recombinational repair of double-strand breaks. Using degenerate oligonucleotides based on conserved amino acid sequences of RAD52 and rad22, its counterpart from Schizosaccharomyces pombe, RAD52 homologs from man and mouse were

  9. Chromosomal localization of three repair genes: the xeroderma pigmentosum group C gene and two human homologs of yeast RAD23.

    NARCIS (Netherlands)

    P.J. van der Spek (Peter); E.M.E. Smit (Elisabeth); H.B. Beverloo (Berna); K. Sugasawa (Kaoru); C. Matsutani; F. Hanaoka (Fumio); J.H.J. Hoeijmakers (Jan); A. Hagemeier

    1994-01-01

    textabstractThe nucleotide excision repair (NER) disorder xeroderma pigmentosum (XP) is characterized by sun (UV) sensitivity, predisposition to skin cancer, and extensive genetic heterogeneity. Recently, we reported the cloning and analysis of three human NER genes, XPC, HHR23A, and HHR23B. The

  10. An update on targeted gene repair in mammalian cells: methods and mechanisms

    Directory of Open Access Journals (Sweden)

    Bolund Lars

    2011-02-01

    Full Text Available Abstract Transfer of full-length genes including regulatory elements has been the preferred gene therapy strategy for clinical applications. However, with significant drawbacks emerging, targeted gene alteration (TGA has recently become a promising alternative to this method. By means of TGA, endogenous DNA repair pathways of the cell are activated leading to specific genetic correction of single-base mutations in the genome. This strategy can be implemented using single-stranded oligodeoxyribonucleotides (ssODNs, small DNA fragments (SDFs, triplex-forming oligonucleotides (TFOs, adeno-associated virus vectors (AAVs and zinc-finger nucleases (ZFNs. Despite difficulties in the use of TGA, including lack of knowledge on the repair mechanisms stimulated by the individual methods, the field holds great promise for the future. The objective of this review is to summarize and evaluate the different methods that exist within this particular area of human gene therapy research.

  11. Inactivation of RAD52 and HDF1 DNA repair genes leads to ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 42; Issue 2. Inactivation of RAD52 and HDF1 DNA repair genes leads to premature chronological aging and cellular instability. SILVIA MERCADO-SÁENZ BEATRIZ LÓPEZ-DÍAZ FRANCISCO SENDRA-PORTERO MANUEL MARTÍNEZ-MORILLO MIGUEL J RUIZ-GÓMEZ.

  12. DHR6, a Drosophila homolog of the yeast DNA repair gene RAD6.

    NARCIS (Netherlands)

    M.H.M. Koken (Marcel); P. Reynolds (Paul); D. Bootsma (Dirk); J.H.J. Hoeijmakers (Jan); S. Prakash; L. Prakash

    1991-01-01

    textabstractThe RAD6 gene of the yeast Saccharomyces cerevisiae is required for DNA repair, for DNA damage-induced mutagenesis, and for sporulation, and it encodes a ubiquitin-conjugating enzyme. We have cloned the RAD6 homolog from Drosophila melanogaster and find that its encoded protein displays

  13. Selecting patients with young-onset colorectal cancer for mismatch repair gene analysis

    DEFF Research Database (Denmark)

    Walker, M; O'Sullivan, B; Perakath, B

    2007-01-01

    BACKGROUND: Young patients with colorectal cancer are at increased risk of carrying a germline mutation in mismatch repair (MMR) genes. This study investigated the role of clinical criteria and immunohistochemistry for MMR proteins in selecting young patients for mutation testing. METHODS: A cohort...

  14. Patients with systemic sclerosis present increased DNA damage differentially associated with DNA repair gene polymorphisms.

    Science.gov (United States)

    Palomino, Gustavo Martelli; Bassi, Carmen L; Wastowski, Isabela J; Xavier, Danilo J; Lucisano-Valim, Yara M; Crispim, Janaina C O; Rassi, Diane M; Marques-Neto, Joao F; Sakamoto-Hojo, Elza T; Moreau, Philippe; Sampaio-Barros, Percival D; Donadi, Eduardo A

    2014-03-01

    Patients with systemic sclerosis (SSc) exhibit increased toxicity when exposed to genotoxic agents. In our study, we evaluated DNA damage and polymorphic sites in 2 DNA repair genes (XRCC1 Arg399Gln and XRCC4 Ile401Thr) in patients with SSc. A total of 177 patients were studied for DNA repair gene polymorphisms. Fifty-six of them were also evaluated for DNA damage in peripheral blood cells using the comet assay. Compared to controls, the patients as a whole or stratified into major clinical variants (limited or diffuse skin involvement), irrespective of the underlying treatment schedule, exhibited increased DNA damage. XRCC1 (rs: 25487) and XRCC4 (rs: 28360135) allele and genotype frequencies observed in patients with SSc were not significantly different from those observed in controls; however, the XRCC1 Arg399Gln allele was associated with increased DNA damage only in healthy controls and the XRCC4 Ile401Thr allele was associated with increased DNA damage in both patients and controls. Further, the XRCC1 Arg399Gln allele was associated with the presence of antinuclear antibody and anticentromere antibody. No association was observed between these DNA repair gene polymorphic sites and clinical features of patients with SSc. These results corroborate the presence of genomic instability in SSc peripheral blood cells, as evaluated by increased DNA damage, and show that polymorphic sites of the XRCC1 and XRCC4 DNA repair genes may differentially influence DNA damage and the development of autoantibodies.

  15. DNA repair gene XRCC7 G6721T variant and susceptibility to ...

    African Journals Online (AJOL)

    Mostafa Saadat

    2016-02-20

    Feb 20, 2016 ... Abstract Background: The human XRCC7 (MIM: 600899) is a DNA double-strand break repair gene, involved in non-homologous end joining (NHEJ). Polymorphism G6721T (rs7003908) is located in the intron 8 of the XRCC7. This polymorphism may regulate splicing and cause mRNA instability. Aim: The ...

  16. Analysis of DNA repair gene polymorphisms and survival in low-grade and anaplastic gliomas

    DEFF Research Database (Denmark)

    Berntsson, Shala Ghaderi; Wibom, Carl; Sjöström, Sara

    2011-01-01

    different DNA repair genes (ATM, NEIL1, NEIL2, ERCC6 and RPA4) which were associated with survival. Finally, these eight genetic variants were adjusted for treatment, malignancy grade, patient age and gender, leaving one variant, rs4253079, mapped to ERCC6, with a significant association to survival (OR 0...

  17. DNA repair gene XRCC7 G6721T variant and susceptibility to ...

    African Journals Online (AJOL)

    Background: The human XRCC7 (MIM: 600899) is a DNA double-strand break repair gene, involved in non-homologous end joining (NHEJ). Polymorphism G6721T (rs7003908) is located in the intron 8 of the XRCC7. This polymorphism may regulate splicing and cause mRNA instability. Aim: The aim of the present study ...

  18. Arsenic-induced Aurora-A activation contributes to chromosome instability and tumorigenesis

    Science.gov (United States)

    Wu, Chin-Han; Tseng, Ya-Shih; Yang, Chao-Chun; Kao, Yu-Ting; Sheu, Hamm-Ming; Liu, Hsiao-Sheng

    2013-11-01

    Arsenic may cause serious environmental pollution and is a serious industrial problem. Depending on the dosage, arsenic may trigger the cells undergoing either proliferation or apoptosis-related cell death. Because of lack of the proper animal model to study arsenic induced tumorigenesis, the accurate risk level of arsenic exposure has not been determined. Arsenic shows genotoxic effect on human beings who uptake water contaminated by arsenic. Chromosome aberration is frequently detected in arsenic exposure-related diseases and is associated with increased oxidative stress and decreased DNA repairing activity, but the underlying mechanism remains elusive. Aurora-A is a mitotic kinase, over-expression of Aurora-A leads to centrosome amplification, chromosomal instability and cell transformation. We revealed that Aurora-A is over-expressed in the skin and bladder cancer patients from blackfoot-disease endemic areas. Our cell line studies reveal that arsenic exposure between 0.5 μM and 1 μM for 2-7 days are able to induce Aurora-A expression and activation based on promoter activity, RNA and protein analysis. Aurora-A overexpression further increases the frequency of unsymmetrical chromosome segregation through centrosome amplification followed by cell population accumulated at S phase in immortalized keratinocyte (HaCaT) and uroepithelial cells (E7). Furthermore, Aurora-A over-expression was sustained for 1-4 weeks by chronic treatment of immortalized bladder and skin cells with NaAsO2. Aurora-A promoter methylation and gene amplification was not detected in the long-term arsenic treated E7 cells. Furthermore, the expression level of E2F1 transcription factor (E2F1) is increased in the presence of arsenic, and arsenic-related Aurora-A over-expression is transcriptionally regulated by E2F1. We further demonstrated that overexpression of Aurora-A and mutant Ha-ras or Aurora-A and mutant p53 may act additively to trigger arsenic-related bladder and skin cancer

  19. Allele and Genotype Distributions of DNA Repair Gene Polymorphisms in South Indian Healthy Population

    Directory of Open Access Journals (Sweden)

    Katiboina Srinivasa Rao

    2014-01-01

    Full Text Available Various DNA repair pathways protect the structural and chemical integrity of the human genome from environmental and endogenous threats. Polymorphisms of genes encoding the proteins involved in DNA repair have been found to be associated with cancer risk and chemotherapeutic response. In this study, we aim to establish the normative frequencies of DNA repair genes in South Indian healthy population and compare with HapMap populations. Genotyping was done on 128 healthy volunteers from South India, and the allele and genotype distributions were established. The minor allele frequency of Xeroderma pigmentosum group A ( XPA G23A, Excision repair cross-complementing 2 ( ERCC2 /Xeroderma pigmentosum group D ( XPD Lys751Gln, Xeroderma pigmentosum group G ( XPG His46His, XPG Asp1104His, and X-ray repair cross-complementing group 1 ( XRCC1 Arg399Gln polymorphisms were 49.2%, 36.3%, 48.0%, 23.0%, and 34.0% respectively. Ethnic variations were observed in the frequency distribution of these polymorphisms between the South Indians and other HapMap populations. The present work forms the groundwork for cancer association studies and biomarker identification for treatment response and prognosis.

  20. Germline stem cell gene PIWIL2 mediates DNA repair through relaxation of chromatin.

    Directory of Open Access Journals (Sweden)

    De-Tao Yin

    Full Text Available DNA damage response (DDR is an intrinsic barrier of cell to tumorigenesis initiated by genotoxic agents. However, the mechanisms underlying the DDR are not completely understood despite of extensive investigation. Recently, we have reported that ectopic expression of germline stem cell gene PIWIL2 is associated with tumor stem cell development, although the underlying mechanisms are largely unknown. Here we show that PIWIL2 is required for the repair of DNA-damage induced by various types of genotoxic agents. Upon ultraviolet (UV irradiation, silenced PIWIL2 gene in normal human fibroblasts was transiently activated after treatment with UV light. This activation was associated with DNA repair, because Piwil2-deficienct mouse embryonic fibroblasts (mili(-/- MEFs were defective in cyclobutane pyrimidine dimers (CPD repair after UV treatment. As a result, the UV-treated mili(-/- MEFs were more susceptible to apoptosis, as characterized by increased levels of DNA damage-associated apoptotic proteins, such as active caspase-3, cleaved Poly (ADP-ribose polymerase (PARP and Bik. The impaired DNA repair in the mili(-/- MEFs was associated with the reductions of histone H3 acetylation and chromatin relaxation, although the DDR pathway downstream chromatin relaxation appeared not to be directly affected by Piwil2. Moreover, guanine-guanine (Pt-[GG] and double strand break (DSB repair were also defective in the mili(-/- MEFs treated by genotoxic chemicals Cisplatin and ionizing radiation (IR, respectively. The results indicate that Piwil2 can mediate DNA repair through an axis of Piwil2 → histone acetylation → chromatin relaxation upstream DDR pathways. The findings reveal a new role for Piwil2 in DNA repair and suggest that Piwil2 may act as a gatekeeper against DNA damage-mediated tumorigenesis.

  1. Multigene panel analysis identified germline mutations of DNA repair genes in breast and ovarian cancer.

    Science.gov (United States)

    Hirotsu, Yosuke; Nakagomi, Hiroshi; Sakamoto, Ikuko; Amemiya, Kenji; Oyama, Toshio; Mochizuki, Hitoshi; Omata, Masao

    2015-09-01

    Approximately 5-10% of all breast and/or ovarian cancer cases are considered as inherited. BRCA1 and BRCA2 tumor suppressor genes account for a high penetrance of hereditary cases, but familial cases without mutations in these genes can also occur. Despite their low penetrance, other hereditary cancer-related genes are known to be associated with breast and ovarian cancer risk. However, the extent to which these genes prevail in breast and ovarian cancer remains to be elucidated. To estimate the frequency of mutations in these predisposition genes, we analyzed the germline mutations of 25 hereditary cancer-related genes in 155 patients using targeted next-generation sequencing. These subjects included 11 BRCA1/2 mutation-positive cases and 144 negative cases. Of these, three patients (1.9%) had pathogenic mutations in ATM, MRE11A, or MSH6, all of which have a central role in DNA repair and the mismatch repair pathway. The MSH6 splice-site mutation (IVS6+1G>T) was predicted to be pathogenic, as demonstrated by in vitro and immunohistochemical analyses. These results suggested deficiencies in cellular DNA repair functions result in the development of breast and ovarian cancer.

  2. Polymorphisms in DNA Repair Genes and MDR1 and the Risk for Non-Hodgkin Lymphoma

    Directory of Open Access Journals (Sweden)

    Hee Nam Kim

    2014-04-01

    Full Text Available The damage caused by oxidative stress and exposure to cigarette smoke and alcohol necessitate DNA damage repair and transport by multidrug resistance-1 (MDR1. To explore the association between polymorphisms in these genes and non-Hodgkin lymphoma risk, we analyzed 15 polymorphisms of 12 genes in a population-based study in Korea (694 cases and 1700 controls. Four genotypes of DNA repair pathway genes (XRCC1 399 GA, OGG1 326 GG, BRCA1 871 TT, and WRN 787 TT were associated with a decreased risk for NHL [odds ratio (ORXRCC1 GA = 0.80, p = 0.02; OROGG1 GG = 0.70, p = 0.008; ORBRCA1 TT = 0.71, p = 0.048; ORWRN TT = 0.68, p = 0.01]. Conversely, the MGMT 115 CT genotype was associated with an increased risk for NHL (OR = 1.25, p = 0.04. In the MDR1 gene, the 1236 CC genotype was associated with a decreased risk for NHL (OR = 0.74, p = 0.04, and the 3435 CT and TT genotypes were associated with an increased risk (OR3435CT = 1.50, p < 0.0001; OR3435TT = 1.43, p = 0.02. These results suggest that polymorphisms in the DNA repair genes XRCC1, OGG1, BRCA1, WRN1, and MGMT and in the MDR1 gene may affect the risk for NHL in Korean patients.

  3. Loss of transcription factor early growth response gene 1 results in impaired endochondral bone repair.

    Science.gov (United States)

    Reumann, Marie K; Strachna, Olga; Yagerman, Sarah; Torrecilla, Daniel; Kim, Jihye; Doty, Stephen B; Lukashova, Lyudmila; Boskey, Adele L; Mayer-Kuckuk, Philipp

    2011-10-01

    Transcription factors that play a role in ossification during development are expected to participate in postnatal fracture repair since the endochondral bone formation that occurs in embryos is recapitulated during fracture repair. However, inherent differences exist between bone development and fracture repair, including a sudden disruption of tissue integrity followed by an inflammatory response. This raises the possibility that repair-specific transcription factors participate in bone healing. Here, we assessed the consequence of loss of early growth response gene 1 (EGR-1) on endochondral bone healing because this transcription factor has been shown to modulate repair in vascularized tissues. Model fractures were created in ribs of wild type (wt) and EGR-1(-/-) mice. Differences in tissue morphology and composition between these two animal groups were followed over 28 post fracture days (PFDs). In wt mice, bone healing occurred in healing phases characteristic of endochondral bone repair. A similar healing sequence was observed in EGR-1(-/-) mice but was impaired by alterations. A persistent accumulation of fibrin between the disconnected bones was observed on PFD7 and remained pronounced in the callus on PFD14. Additionally, the PFD14 callus was abnormally enlarged and showed increased deposition of mineralized tissue. Cartilage ossification in the callus was associated with hyper-vascularity and -proliferation. Moreover, cell deposits located in proximity to the callus within skeletal muscle were detected on PFD14. Despite these impairments, repair in EGR-1(-/-) callus advanced on PFD28, suggesting EGR-1 is not essential for healing. Together, this study provides genetic evidence that EGR-1 is a pleiotropic regulator of endochondral fracture repair. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Cytogenetic Response to Ionizing Radiation Exposure in Human Fibroblasts with Suppressed Expression of Non-DSB Repair Genes

    Science.gov (United States)

    Zhang, Ye; Rohde, Larry H.; Emami, Kamal; Hammond, Dianne; Mehta, Satish K.; Jeevarajan, Antony S.; Pierson, Duane L.; Wu, Honglu

    2009-01-01

    Changes of gene expression profile are one of the most important biological responses in living cells after ionizing radiation (IR) exposure. Although some studies have shown that genes up-regulated by IR may play important roles in DNA damage repair, the relationship between the regulation of gene expression by IR, particularly genes not known for their roles in double-strand break (DSB) repair, and its impact on cytogenetic responses has not been well studied. The purpose of this study is to identify new roles of IR inducible genes in radiation-induced chromosome aberrations and micronuclei formation. In the study, the expression of 25 genes selected on the basis of their transcriptional changes in response to IR was individually knocked down by small interfering RNA in human fibroblast cells. Frequencies of micronuclei (MN) formation and chromosome aberrations were measured to determine the efficiency of cytogenetic repair, and the fraction of bi-nucleated cells in the MN analysis was used as a marker for cell cycle progression. In response to gamma radiation, the formation of MN was significantly increased by suppressed expression of five genes: Ku70 (DSB repair pathway), XPA (nucleotide excision repair pathway), RPA1 (mismatch repair pathway), RAD17 and RBBP8 (cell cycle control). Knocked-down expression of four genes (MRE11A, RAD51 in the DSB pathway, SESN1, and SUMO1) significantly inhibited cell cycle progression, possibly because of severe impairment of DNA damage repair. Moreover, decreased XPA, p21, or MLH1 expression resulted in both significantly enhanced cell cycle progression and increased yields of chromosome aberrations, indicating that these gene products modulate both cell cycle control and DNA damage repair. Nine of these eleven genes, whose knock-down expression affected cytogenetic repair, were up-regulated in cells exposed to gamma radiation, suggesting that genes transcriptionally modulated by IR were critical to regulate IR

  5. Determining the functional significance of mismatch repair gene missense variants using biochemical and cellular assays

    DEFF Research Database (Denmark)

    Heinen, Christopher D; Juel Rasmussen, Lene

    2012-01-01

    provided an important experimental tool for studying the functional consequences of VUS. However, beyond this repair assay, a number of other experimental methods have been developed that allow us to test the effect of a VUS on discrete biochemical steps or other aspects of MMR function. Here, we describe......ABSTRACT: With the discovery that the hereditary cancer susceptibility disease Lynch syndrome (LS) is caused by deleterious germline mutations in the DNA mismatch repair (MMR) genes nearly 20 years ago, genetic testing can now be used to diagnose this disorder in patients. A definitive diagnosis...

  6. Transformation and characterization of an arsenic gene operon from urease-positive thermophilic Campylobacter (UPTC) in Escherichia coli.

    Science.gov (United States)

    Matsuda, M; Kuribayashi, T; Yamamoto, S; Millar, B C; Moore, J E

    2016-01-01

    An arsenate susceptibility test was performed with transformed and cultured Escherichia coli DH5α cells, which carried recombinant DNA of full-length arsenic (ars) operon, namely a putative membrane permease, ArsP; a transcriptional repressor, ArsR; an arsenate reductase, ArsC; and an arsenical-resistance membrane transporter, Acr3, from the Japanese urease-positive thermophilic Campylobacter lari (UPTC) CF89-12. The E. coli DH5α transformant showed reduced susceptibility to arsenate (~1536 μg/mL), compared to the control. Thus, these ars four-genes from the UPTC CF89-12 strain cells could confer a reduced susceptibility to arsenate in the transformed and E. coli DH5α cells. E. coli transformants with truncated ars operons, acr3 (acr3) and arsC-acr3 (∆arsC-acr3), of the ars operon, showed an MIC value of 384 μg/mL (~384 μg/mL), similar to the E. coli cells which carried the pGEM-T vector (control). Reverse transcription PCR confirmed in vivo transcription of recombinant full-length ars operon and deletion variants (∆acr3 and ∆arsC-acr3) in the transformed E. coli cells.

  7. Erythrosine B and quinoline yellow dyes regulate DNA repair gene expression in human HepG2 cells.

    Science.gov (United States)

    Chequer, Farah Md; Venancio, Vinicius P; Almeida, Mara R; Aissa, Alexandre F; Bianchi, Maria Lourdes P; Antunes, Lusânia Mg

    2017-10-01

    Erythrosine B (ErB) is a cherry pink food colorant and is widely used in foods, drugs, and cosmetics. Quinoline yellow (QY) is a chinophthalon derivative used in cosmetic compositions for application to the skin, lips, and/or body surface. Previously, ErB and QY synthetic dyes were found to induce DNA damage in HepG2 cells. The aim of this study was to investigate the molecular basis underlying the genotoxicity attributed to ErB and QY using the RT2 Profiler polymerase chain reaction array and by analyzing the expression profile of 84 genes involved in cell cycle arrest, apoptosis, and DNA repair in HepG2 cells. ErB (70 mg/L) significantly decreased the expression of two genes ( FEN1 and REV1) related to DNA base repair. One gene ( LIG1) was downregulated and 20 genes related to ATR/ATM signaling ( ATR, RBBP8, RAD1, CHEK1, CHEK2, TOPB1), nucleotide excision repair ( ERCC1, XPA), base excision repair ( FEN1, MBD4), mismatch repair ( MLH1, MSH3, TP73), double strand break repair ( BLM), other DNA repair genes ( BRIP1, FANCA, GADD45A, REV1), and apoptosis ( BAX, PPP1R15A) were significantly increased after treatment with QY (20 mg/L). In conclusion, our data suggest that the genotoxic mechanism of ErB and QY dyes involves the modulation of genes related to the DNA repair system and cell cycle.

  8. Comprehensive analysis of DNA repair gene variants and risk of meningioma

    DEFF Research Database (Denmark)

    Bethke, L.; Murray, A.; Webb, E.

    2008-01-01

    BACKGROUND: Meningiomas account for up to 37% of all primary brain tumors. Genetic susceptibility to meningioma is well established, with the risk among relatives of meningioma patients being approximately threefold higher than that in the general population. A relationship between risk...... of meningioma and exposure to ionizing radiation is also well known and led us to examine whether variants in DNA repair genes contribute to disease susceptibility. METHODS: We analyzed 1127 tagging single-nucleotide polymorphisms (SNPs) that were selected to capture most of the common variation in 136 DNA...... repair genes in five case-control series (631 case patients and 637 control subjects) from four countries in Europe. We also analyzed 388 putative functional SNPs in these genes for their association with meningioma. All statistical tests were two-sided. RESULTS: The SNP rs4968451, which maps to intron 4...

  9. Mismatch repair gene mutation spectrum in the Swedish Lynch syndrome population

    DEFF Research Database (Denmark)

    Lagerstedt-Robinson, Kristina; Rohlin, Anna; Aravidis, Christos

    2016-01-01

    Lynch syndrome caused by constitutional mismatch‑repair defects is one of the most common hereditary cancer syndromes with a high risk for colorectal, endometrial, ovarian and urothelial cancer. Lynch syndrome is caused by mutations in the mismatch repair (MMR) genes i.e., MLH1, MSH2, MSH6 and PMS2....... After 20 years of genetic counseling and genetic testing for Lynch syndrome, we have compiled the mutation spectrum in Sweden with the aim to provide a population-based perspective on the contribution from the different MMR genes, the various types of mutations and the influence from founder mutations....... Mutation data were collected on a national basis from all laboratories involved in genetic testing. Mutation analyses were performed using mainly Sanger sequencing and multiplex ligation-dependent probe amplification. A total of 201 unique disease-predisposing MMR gene mutations were identified in 369...

  10. Arsenic Methylation and its Relationship to Abundance and Diversity of arsM Genes in Composting Manure

    Science.gov (United States)

    Zhai, Weiwei; Wong, Mabel T.; Luo, Fei; Hashmi, Muhammad Z.; Liu, Xingmei; Edwards, Elizabeth A.; Tang, Xianjin; Xu, Jianming

    2017-03-01

    Although methylation is regarded as one of the main detoxification pathways for arsenic (As), current knowledge about this process during manure composting remains limited. In this study, two pilot-scale compost piles were established to treat manure contaminated with As. An overall accumulation of methylated As occurred during 60 day-composting time. The concentration of monomethylarsonic acid (MMA) increased from 6 to 190 μg kg-1 within 15 days and decreased to 35 μg kg-1 at the end of the maturing phase; while the concentration of dimethylarsinic acid (DMA) continuously increased from 33 to 595 μg kg-1 over the composting time. The arsM gene copies increased gradually from 0.08 × 109 to 6.82 × 109 copies g-1 dry mass over time and correlated positively to the concentrations of methylated As. 16S rRNA gene sequencing and arsM clone library analysis confirmed the high abundance and diversity of arsM genes. Many of these genes were related to those from known As-methylating microbes, including Streptomyces sp., Amycolatopsis mediterranei and Sphaerobacter thermophiles. These results demonstrated that As methylation during manure composting is significant and, for the first time, established a linkage between As biomethylation and the abundance and diversity of the arsM functional genes in composting manure.

  11. Transcriptional and post-transcriptional regulation of nucleotide excision repair genes in human cells

    Energy Technology Data Exchange (ETDEWEB)

    Lefkofsky, Hailey B. [Translational Oncology Program, University of Michigan Medical School, Ann Arbor, MI (United States); Veloso, Artur [Translational Oncology Program, University of Michigan Medical School, Ann Arbor, MI (United States); Department of Radiation Oncology, University of Michigan Medical School, Ann Arbor, MI (United States); Bioinformatics Program, Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI (United States); Ljungman, Mats, E-mail: ljungman@umich.edu [Translational Oncology Program, University of Michigan Medical School, Ann Arbor, MI (United States); Department of Radiation Oncology, University of Michigan Medical School, Ann Arbor, MI (United States); Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI (United States)

    2015-06-15

    Nucleotide excision repair (NER) removes DNA helix-distorting lesions induced by UV light and various chemotherapeutic agents such as cisplatin. These lesions efficiently block the elongation of transcription and need to be rapidly removed by transcription-coupled NER (TC-NER) to avoid the induction of apoptosis. Twenty-nine genes have been classified to code for proteins participating in nucleotide excision repair (NER) in human cells. Here we explored the transcriptional and post-transcriptional regulation of these NER genes across 13 human cell lines using Bru-seq and BruChase-seq, respectively. Many NER genes are relatively large in size and therefore will be easily inactivated by UV-induced transcription-blocking lesions. Furthermore, many of these genes produce transcripts that are rather unstable. Thus, these genes are expected to rapidly lose expression leading to a diminished function of NER. One such gene is ERCC6 that codes for the CSB protein critical for TC-NER. Due to its large gene size and high RNA turnover rate, the ERCC6 gene may act as dosimeter of DNA damage so that at high levels of damage, ERCC6 RNA levels would be diminished leading to the loss of CSB expression, inhibition of TC-NER and the promotion of cell death.

  12. Characterization, real-time quantification and in silico modeling of arsenate reductase (arsC) genes in arsenic-resistant Herbaspirillum sp. GW103.

    Science.gov (United States)

    Govarthanan, Muthusamy; Lee, Sang-Myeong; Kamala-Kannan, Seralathan; Oh, Byung-Taek

    2015-04-01

    This study investigated the mechanism of arsenic resistance in the diazotrophic bacterium Herbaspirillum sp. GW103 isolated from rhizosphere soil of Phragmites austrails. The isolate Herbaspirillum sp. GW103 exhibited maximum tolerance to arsenic (550 mg/L). Four different arsenate reductase (arsC) genes (arsC1, arsC2, arsC3 and arsC4) were located in the genome of the isolate Herbaspirillum sp. GW103. The expression pattern of the arsC1 differed from other genes. All four types of arsC genes had different protein secondary structures and stereochemical properties. Molecular modeling and structural analysis of arsC genes revealed close structural homology with arsC family proteins from Escherichia coli (PDB ID: 1I9D) and Pseudomonas aeruginosa (PDB ID: 1RW1). Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  13. Treating Duchenne Cardiomyopathy in the Mouse Model by Gene Repair

    Science.gov (United States)

    2017-08-01

    Lipid nanoparticles and liposomes have been used to deliver exon-skipping AONs for DMD gene therapy. In the former, cationic lipids are used to coat ...the delivery tool. AAV is a bio- nanoparticle . We published a review article on the current state-of-art on nanotherapy (both viral and noviral) for...bearing binding domains for various materials including gold nanoparticles and carbon nanotubes for testing (at the LaBean lab) the assembly of

  14. A data mining approach for classifying DNA repair genes into ageing-related or non-ageing-related.

    Science.gov (United States)

    Freitas, Alex A; Vasieva, Olga; de Magalhães, João Pedro

    2011-01-12

    The ageing of the worldwide population means there is a growing need for research on the biology of ageing. DNA damage is likely a key contributor to the ageing process and elucidating the role of different DNA repair systems in ageing is of great interest. In this paper we propose a data mining approach, based on classification methods (decision trees and Naive Bayes), for analysing data about human DNA repair genes. The goal is to build classification models that allow us to discriminate between ageing-related and non-ageing-related DNA repair genes, in order to better understand their different properties. The main patterns discovered by the classification methods are as follows: (a) the number of protein-protein interactions was a predictor of DNA repair proteins being ageing-related; (b) the use of predictor attributes based on protein-protein interactions considerably increased predictive accuracy of attributes based on Gene Ontology (GO) annotations; (c) GO terms related to "response to stimulus" seem reasonably good predictors of ageing-relatedness for DNA repair genes; (d) interaction with the XRCC5 (Ku80) protein is a strong predictor of ageing-relatedness for DNA repair genes; and (e) DNA repair genes with a high expression in T lymphocytes are more likely to be ageing-related. The above patterns are broadly integrated in an analysis discussing relations between Ku, the non-homologous end joining DNA repair pathway, ageing and lymphocyte development. These patterns and their analysis support non-homologous end joining double strand break repair as central to the ageing-relatedness of DNA repair genes. Our work also showcases the use of protein interaction partners to improve accuracy in data mining methods and our approach could be applied to other ageing-related pathways.

  15. A data mining approach for classifying DNA repair genes into ageing-related or non-ageing-related

    Directory of Open Access Journals (Sweden)

    Vasieva Olga

    2011-01-01

    Full Text Available Abstract Background The ageing of the worldwide population means there is a growing need for research on the biology of ageing. DNA damage is likely a key contributor to the ageing process and elucidating the role of different DNA repair systems in ageing is of great interest. In this paper we propose a data mining approach, based on classification methods (decision trees and Naive Bayes, for analysing data about human DNA repair genes. The goal is to build classification models that allow us to discriminate between ageing-related and non-ageing-related DNA repair genes, in order to better understand their different properties. Results The main patterns discovered by the classification methods are as follows: (a the number of protein-protein interactions was a predictor of DNA repair proteins being ageing-related; (b the use of predictor attributes based on protein-protein interactions considerably increased predictive accuracy of attributes based on Gene Ontology (GO annotations; (c GO terms related to "response to stimulus" seem reasonably good predictors of ageing-relatedness for DNA repair genes; (d interaction with the XRCC5 (Ku80 protein is a strong predictor of ageing-relatedness for DNA repair genes; and (e DNA repair genes with a high expression in T lymphocytes are more likely to be ageing-related. Conclusions The above patterns are broadly integrated in an analysis discussing relations between Ku, the non-homologous end joining DNA repair pathway, ageing and lymphocyte development. These patterns and their analysis support non-homologous end joining double strand break repair as central to the ageing-relatedness of DNA repair genes. Our work also showcases the use of protein interaction partners to improve accuracy in data mining methods and our approach could be applied to other ageing-related pathways.

  16. Differential DNA methylation profile of key genes in malignant prostate epithelial cells transformed by inorganic arsenic or cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Pelch, Katherine E.; Tokar, Erik J. [National Toxicology Program Laboratory, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 (United States); Merrick, B. Alex [Molecular Toxicology and Informatics Group, Biomolecular Screening Branch, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Morrisville, NC 27560 (United States); Waalkes, Michael P., E-mail: waalkes@niehs.nih.gov [National Toxicology Program Laboratory, Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 (United States)

    2015-08-01

    Previous work shows altered methylation patterns in inorganic arsenic (iAs)- or cadmium (Cd)-transformed epithelial cells. Here, the methylation status near the transcriptional start site was assessed in the normal human prostate epithelial cell line (RWPE-1) that was malignantly transformed by 10 μM Cd for 11 weeks (CTPE) or 5 μM iAs for 29 weeks (CAsE-PE), at which time cells showed multiple markers of acquired cancer phenotype. Next generation sequencing of the transcriptome of CAsE-PE cells identified multiple dysregulated genes. Of the most highly dysregulated genes, five genes that can be relevant to the carcinogenic process (S100P, HYAL1, NTM, NES, ALDH1A1) were chosen for an in-depth analysis of the DNA methylation profile. DNA was isolated, bisulfite converted, and combined bisulfite restriction analysis was used to identify differentially methylated CpG sites, which was confirmed with bisulfite sequencing. Four of the five genes showed differential methylation in transformants relative to control cells that was inversely related to altered gene expression. Increased expression of HYAL1 (> 25-fold) and S100P (> 40-fold) in transformants was correlated with hypomethylation near the transcriptional start site. Decreased expression of NES (> 15-fold) and NTM (> 1000-fold) in transformants was correlated with hypermethylation near the transcriptional start site. ALDH1A1 expression was differentially expressed in transformed cells but was not differentially methylated relative to control. In conclusion, altered gene expression observed in Cd and iAs transformed cells may result from altered DNA methylation status. - Highlights: • Cd and iAs are known human carcinogens, yet neither appears directly mutagenic. • Prior data suggest epigenetic modification plays a role in Cd or iAs induced cancer. • Altered methylation of four misregulated genes was found in Cd or iAs transformants. • The resulting altered gene expression may be relevant to cellular

  17. Germline mutations in DNA repair genes predispose asbestos-exposed patients to malignant pleural mesothelioma.

    Science.gov (United States)

    Betti, Marta; Casalone, Elisabetta; Ferrante, Daniela; Aspesi, Anna; Morleo, Giulia; Biasi, Alessandra; Sculco, Marika; Mancuso, Giuseppe; Guarrera, Simonetta; Righi, Luisella; Grosso, Federica; Libener, Roberta; Pavesi, Mansueto; Mariani, Narciso; Casadio, Caterina; Boldorini, Renzo; Mirabelli, Dario; Pasini, Barbara; Magnani, Corrado; Matullo, Giuseppe; Dianzani, Irma

    2017-10-01

    Malignant pleural mesothelioma (MPM) is a rare, aggressive cancer caused by asbestos exposure. An inherited predisposition has been suggested to explain multiple cases in the same family and the observation that not all individuals highly exposed to asbestos develop the tumor. Germline mutations in BAP1 are responsible for a rare cancer predisposition syndrome that includes predisposition to mesothelioma. We hypothesized that other genes involved in hereditary cancer syndromes could be responsible for the inherited mesothelioma predisposition. We investigated the prevalence of germline variants in 94 cancer-predisposing genes in 93 MPM patients with a quantified asbestos exposure. Ten pathogenic truncating variants (PTVs) were identified in PALB2, BRCA1, FANCI, ATM, SLX4, BRCA2, FANCC, FANCF, PMS1 and XPC. All these genes are involved in DNA repair pathways, mostly in homologous recombination repair. Patients carrying PTVs represented 9.7% of the panel and showed lower asbestos exposure than did all the other patients (p = 0.0015). This suggests that they did not efficiently repair the DNA damage induced by asbestos and leading to carcinogenesis. This study shows that germline variants in several genes may increase MPM susceptibility in the presence of asbestos exposure and may be important for specific treatment. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  18. DNA Repair Gene Polymorphisms in Relation to Non-Small Cell Lung Cancer Survival

    Directory of Open Access Journals (Sweden)

    Yuliang Su

    2015-07-01

    Full Text Available Background: Single nucleotide polymorphisms (SNPs in the DNA repair genes are suspected to be related to the survival of lung cancer patients due to their possible influence on DNA repair capacity (DRC. However, the study results are inconsistent. Methods: A follow-up study of 610 non-small cell lung cancer (NSCLC patients was conducted to investigate genetic polymorphisms associated with the DNA repair genes in relation to NSCLC survival; 6 SNPs were genotyped, including XRCC1 (rs25487 G>A, hOGG1 (rs1052133 C>G, MUTYH (rs3219489 G>C, XPA (rs1800975 G>A, ERCC2 (rs1799793 G>A and XRCC3 (rs861539 C>T. Kaplan-Meier survival curve and Cox proportional hazards regression analyses were performed. SNP-SNP interaction was also examined using the survival tree analysis. Results: Advanced disease stage and older age at diagnosis were associated with poor prognosis of NSCLC. Patients with the variant ‘G' allele of hOGG1 rs1052133 had poor overall survival compared with those with the homozygous wild ‘CC' genotype, especially in female patients, adenocarcinoma histology, early stage, light smokers and without family history of cancer. For never smoking female lung cancer patients, individuals carrying homozygous variant ‘AA' genotype of XPA had shorter survival time compared to those with wild ‘G' alleles. Furthermore, females carrying homozygous variant XPA and hOGG1 genotypes simultaneously had 2.78-fold increased risk for death. Among all 6 polymorphisms, the homozygous variant ‘AA' of XPA carriers had poor prognosis compared to the carriers of wild ‘G' alleles of XPA together with other base excision repair (BER polymorphisms. Conclusions: Besides disease stage and age, the study found DNA repair gene polymorphisms were associated with lung cancer survival.

  19. Glial kon/NG2 gene network for central nervous system repair

    Directory of Open Access Journals (Sweden)

    Maria Losada-Perez

    2017-01-01

    Full Text Available The glial regenerative response to central nervous system (CNS injury, although limited, can be harnessed to promote regeneration and repair. Injury provokes the proliferation of ensheathing glial cells, which can differentiate to remyelinate axons, and partially restore function. This response is evolutionarily conserved, strongly implying an underlying genetic mechanism. In mammals, it is elicited by NG2 glia, but most often newly generated cells fail to differentiate. Thus an important goal had been to find out how to promote glial differentiation following the proliferative response. A gene network involving Notch and prospero (pros controls the balance between glial proliferation and differentiation in flies and mice, and promotes CNS repair at least in fruit-flies. A key missing link had been how to relate the function of NG2 to this gene network. Recent findings by Losada-Perez et al., published in JCB, demonstrated that the Drosophila NG2 homologue kon-tiki (kon is functionally linked to Notch and pros in glia. By engaging in two feedback loops with Notch and Pros, in response to injury, Kon can regulate both glial cell number and glial shape homeostasis, essential for repair. Drosophila offers powerful genetics to unravel the control of stem and progenitor cells for regeneration and repair.

  20. Arsenic and ultraviolet radiation exposure: melanoma in a New Mexico non-Hispanic white population.

    Science.gov (United States)

    Yager, Janice W; Erdei, Esther; Myers, Orrin; Siegel, Malcolm; Berwick, Marianne

    2016-06-01

    Cases of cutaneous melanoma and controls were enrolled in a New Mexico population-based study; subjects were administered questionnaires concerning ultraviolet (UV) and inorganic arsenic (iAs) exposure. Historical iAs exposure was estimated. UV exposure estimates were also derived using geospatial methods. Drinking water samples were collected for iAs analysis. Blood samples were collected for DNA repair (Comet) and DNA repair gene polymorphism assays. Arsenic concentrations were determined in urine and toenail samples. UV exposures during the previous 90 days did not vary significantly between cases and controls. Mean (±SD) current home iAs drinking water was not significantly different for cases and controls [3.98 μg/L (±3.67) vs. 3.47 μg/L (±2.40)]. iAs exposure showed no effect on DNA repair or association with melanoma. Results did not corroborate a previously reported association between toenail As and melanoma risk. Arsenic biomarkers in urine and toenail were highly significantly correlated with iAs in drinking water. A UV-DNA repair interaction for UV exposure over the previous 7-90 days was shown; cases had higher DNA damage than controls at low UV values. This novel finding suggests that melanoma cases may be more sensitive to low-level UV exposure than are controls. A UV-APEX1 interaction was shown. Subjects with the homozygous rare APEX1 DNA repair gene allele had a higher risk of early melanoma diagnosis at low UV exposure compared with those with the homozygous wild type or the heterozygote. Notably, a UV-arsenic interaction on inhibition of DNA repair was not observed at iAs drinking water concentrations below 10 ppb (μg/L).

  1. Immunohistochemical and DNA sequencing analysis on human mismatch repair gene MLH1 in cervical squamous cell carcinoma with LOH of this gene

    NARCIS (Netherlands)

    Hu, X.; Guo, Z.; Pang, T.; Li, Q.; Afink, G.; Pontén, J.

    2000-01-01

    BACKGROUND: The human MLH1 gene (hMLH1) is one of the DNA mismatch repair genes. Defects in these genes are believed to be the underlying cause of microsatellite instability (MSI). MSI has been demonstrated in many human cancers such as colon cancer and some female-specific tumors. The hMLH1 gene

  2. Localization of the nucleotide excision repair gene ERCC-6 to human chromosome 10q11-q21.

    NARCIS (Netherlands)

    C. Troelstra (Christine); R.M. Landsvater; J. Wiegant; M. van der Ploeg; G. Viel; C.H.C.M. Buys; J.H.J. Hoeijmakers (Jan)

    1992-01-01

    textabstractWe have cloned the human DNA excision repair gene ERCC6 by virtue of its ability to correct the uv sensitivity of Chinese hamster overy cell mutant UV61. This mutant is a member of complementation group 6 of the nucleotide excision repair-deficient rodent mutants. By means of in situ

  3. Dysregulation of DNA methylation induced by past arsenic treatment causes persistent genomic instability in mammalian cells.

    Science.gov (United States)

    Mauro, Maurizio; Caradonna, Fabio; Klein, Catherine B

    2016-03-01

    The mechanisms by which arsenic-induced genomic instability is initiated and maintained are poorly understood. To investigate potential epigenetic mechanisms, in this study we evaluated global DNA methylation levels in V79 cells and human HaCaT keratinocytes at several time points during expanded growth of cell cultures following removal of arsenite exposures. We have found altered genomic methylation patterns that persisted up to 40 cell generations in HaCaT cells after the treatments were withdrawn. Moreover, mRNA expression levels were evaluated by RT-PCR for DNMT1, DNMT3A, DNMT3B, HMLH1, and HMSH2 genes, demonstrating that the down regulation of DNMT3A and DNMT3B genes, but not DNMT1, occurred in an arsenic dose-dependent manner, and persisted for many cell generations following removal of the arsenite, offering a plausible mechanism of persistently genotoxic arsenic action. Analyses of promoter methylation status of the DNA mismatch repair genes HMLH1 and HMSH2 show that HMSH2, but not HMLH1, was epigenetically regulated by promoter hypermethylation changes following arsenic treatment. The results reported here demonstrate that arsenic exposure promptly induces genome-wide global DNA hypomethylation, and some specific gene promoter methylation changes, that persist for many cell generations following withdrawal of arsenite, supporting the hypothesis that the cells undergo epigenetic reprogramming at both the gene and genome level that is durable over many cell generations in the absence of further arsenic treatment. These DNA methylation changes, in concert with other known epigenome alterations, are likely contributing to long-lasting arsenic-induced genomic instability that manifests in several ways, including aberrant chromosomal effects. © 2015 Wiley Periodicals, Inc.

  4. DNA repair gene ERCC2 polymorphisms and associations with breast and ovarian cancer risk.

    Science.gov (United States)

    Bernard-Gallon, Dominique; Bosviel, Rémy; Delort, Laetitia; Fontana, Luc; Chamoux, Alain; Rabiau, Nadège; Kwiatkowski, Fabrice; Chalabi, Nasséra; Satih, Samir; Bignon, Yves-Jean

    2008-05-02

    Breast and ovarian cancers increased in the last decades. Except rare cases with a genetic predisposition and high penetrance, these pathologies are viewed as a polygenic disease. In this concept, association studies look for genetic variations such as polymorphisms in low penetrance genes, i.e. genes in interaction with environmental factors. DNA repair systems that protect the genome from deleterious endogenous and exogenous damages have been shown to have significantly reduced. In particular, enzymes of the nucleotide excision repair pathway are suspected to be implicated in cancer. In this study, 2 functional polymorphisms in a DNA repair gene ERCC2 were analyzed. The population included 911 breast cancer cases, 51 ovarian cancer cases and 1000 controls. The genotyping of 2 SNP (Single Nucleotide Polymorphism) was carried out on the population with the MGB (Minor Groove Binder) probe technique which consists of the use of the allelic discrimination with the Taqman method. This study enabled us to show an increase in risk of breast cancer with no oral contraceptive users and with women exhibiting a waist-to-hip ratio (WHR) > 0.85 for Asn homozygous for ERCC2 312.

  5. DNA repair gene ERCC2 polymorphisms and associations with breast and ovarian cancer risk

    Directory of Open Access Journals (Sweden)

    Rabiau Nadège

    2008-05-01

    Full Text Available Abstract Breast and ovarian cancers increased in the last decades. Except rare cases with a genetic predisposition and high penetrance, these pathologies are viewed as a polygenic disease. In this concept, association studies look for genetic variations such as polymorphisms in low penetrance genes, i.e. genes in interaction with environmental factors. DNA repair systems that protect the genome from deleterious endogenous and exogenous damages have been shown to have significantly reduced. In particular, enzymes of the nucleotide excision repair pathway are suspected to be implicated in cancer. In this study, 2 functional polymorphisms in a DNA repair gene ERCC2 were analyzed. The population included 911 breast cancer cases, 51 ovarian cancer cases and 1000 controls. The genotyping of 2 SNP (Single Nucleotide Polymorphism was carried out on the population with the MGB (Minor Groove Binder probe technique which consists of the use of the allelic discrimination with the Taqman® method. This study enabled us to show an increase in risk of breast cancer with no oral contraceptive users and with women exhibiting a waist-to-hip ratio (WHR > 0.85 for Asn homozygous for ERCC2 312.

  6. Incomplete complementation of the DNA repair defect in cockayne syndrome cells by the denV gene from bacteriophage T4 suggests a deficiency in base excision repair.

    Science.gov (United States)

    Francis, M A; Bagga, P S; Athwal, R S; Rainbow, A J

    1997-10-01

    Endonuclease V (denV) from bacteriophage T4 has been examined for its ability to complement the repair defect in Cockayne syndrome (CS) cells of complementation groups A and B. CS is an autosomal recessive disorder characterized by hypersensitivity to UV light and a defect in the preferential repair of UV-induced lesions in transcriptionally active DNA by the nucleotide excision repair (NER) pathway. The denV gene was introduced into non-transformed normal and CS fibroblasts transiently via a recombinant adenovirus (Ad) vector and into SV40-transformed normal and CS cells via a retroviral vector. Expression of denV in CS-A cells resulted in partial correction of the UV-sensitive phenotype in assays of gene-specific repair and cell viability, while correction of CS-B cells by expression of denV in the same assays was minimal or non-existent. In contrast, denV expression led to enhanced host cell reactivation (HCR) of viral DNA synthesis in both CS complementation groups to near normal levels. DenV is a glycosylase which is specific for cyclobutane-pyrimidine dimers (CPDs) but does not recognize other UV-induced lesions. Previous work has indicated that CS cells can efficiently repair all non-CPD UV-induced transcription blocking lesions (S.F. Barrett et al.. Mutation Res. 255 (1991) 281-291 [1]) and that denV incised lesions are believed to be processed via the base excision repair (BER) pathway. The inability of denV to complement the NER defect in CS cells to normal levels implies an impaired ability to process denV incised lesions by the BER pathway, and suggests a role for the CS genes, particularly the CS-B gene, in BER.

  7. A comparison of synthetic oligodeoxynucleotides, DNA fragments and AAV-1 for targeted episomal and chromosomal gene repair

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    Leclerc Xavier

    2009-04-01

    Full Text Available Abstract Background Current strategies for gene therapy of inherited diseases consist in adding functional copies of the gene that is defective. An attractive alternative to these approaches would be to correct the endogenous mutated gene in the affected individual. This study presents a quantitative comparison of the repair efficiency using different forms of donor nucleic acids, including synthetic DNA oligonucleotides, double stranded DNA fragments with sizes ranging from 200 to 2200 bp and sequences carried by a recombinant adeno-associated virus (rAAV-1. Evaluation of each gene repair strategy was carried out using two different reporter systems, a mutated eGFP gene or a dual construct with a functional eGFP and an inactive luciferase gene, in several different cell systems. Gene targeting events were scored either following transient co-transfection of reporter plasmids and donor DNAs, or in a system where a reporter construct was stably integrated into the chromosome. Results In both episomal and chromosomal assays, DNA fragments were more efficient at gene repair than oligonucleotides or rAAV-1. Furthermore, the gene targeting frequency could be significantly increased by using DNA repair stimulating drugs such as doxorubicin and phleomycin. Conclusion Our results show that it is possible to obtain repair frequencies of 1% of the transfected cell population under optimized transfection protocols when cells were pretreated with phleomycin using rAAV-1 and dsDNA fragments.

  8. A genome-scale DNA repair RNAi screen identifies SPG48 as a novel gene associated with hereditary spastic paraplegia.

    Directory of Open Access Journals (Sweden)

    Mikołaj Słabicki

    Full Text Available DNA repair is essential to maintain genome integrity, and genes with roles in DNA repair are frequently mutated in a variety of human diseases. Repair via homologous recombination typically restores the original DNA sequence without introducing mutations, and a number of genes that are required for homologous recombination DNA double-strand break repair (HR-DSBR have been identified. However, a systematic analysis of this important DNA repair pathway in mammalian cells has not been reported. Here, we describe a genome-scale endoribonuclease-prepared short interfering RNA (esiRNA screen for genes involved in DNA double strand break repair. We report 61 genes that influenced the frequency of HR-DSBR and characterize in detail one of the genes that decreased the frequency of HR-DSBR. We show that the gene KIAA0415 encodes a putative helicase that interacts with SPG11 and SPG15, two proteins mutated in hereditary spastic paraplegia (HSP. We identify mutations in HSP patients, discovering KIAA0415/SPG48 as a novel HSP-associated gene, and show that a KIAA0415/SPG48 mutant cell line is more sensitive to DNA damaging drugs. We present the first genome-scale survey of HR-DSBR in mammalian cells providing a dataset that should accelerate the discovery of novel genes with roles in DNA repair and associated medical conditions. The discovery that proteins forming a novel protein complex are required for efficient HR-DSBR and are mutated in patients suffering from HSP suggests a link between HSP and DNA repair.

  9. A presumed DNA helicase, encoded by the excision repair gene ERCC-3 is involved in the human repair disorders xeroderma pigmentosum and Cockayne's syndrome.

    NARCIS (Netherlands)

    G. Weeda (Geert); R.C.A. van Ham; W. Vermeulen (Wim); D. Bootsma (Dirk); A.J. van der Eb; J.H.J. Hoeijmakers (Jan)

    1990-01-01

    textabstractThe human gene ERCC-3 specifically corrects the defect in an early step of the DNA excision repair pathway of UV-sensitive rodent mutants of complementation group 3. The predicted 782 animo acid ERCC-3 protein harbors putative nucleotide, chromatin, and helix-turn-helix DNA binding

  10. Methylation profile analysis of DNA repair genes in hepatocellular carcinoma with MS-MLPA.

    Science.gov (United States)

    Ozer, Ozge; Bilezikci, Banu; Aktas, Sema; Sahin, Feride I

    2013-12-01

    Hepatocellular carcinoma (HCC) is one of the rare tumors with well-defined risk factors. The multifactorial etiology of HCC can be explained by its complex molecular pathogenesis. In the current study, the methylation status of 7 genes involved in DNA repair mechanisms, namely MLH1, PMS2, MSH6, MSH2, MGMT, MSH3, and MLH3, was investigated in tumor samples from HCC patients, using the methylation-specific-multiplex ligated probe amplification method and the results were correlated with available clinical findings. The most common etiological factor in these cases was the presence of hepatitis B alone (47.2%). Among the 56 cases that were studied, promoter methylation was detected in at least one of the genes in 27 (48.2%) cases, only in 1 gene in 13 (23.2%) cases, and in >1 gene in 14 (25%) cases. Of the 7 genes investigated, methylation was most frequently observed in MSH3, in 14 (25%) cases. Methylation of at least 1 gene was significantly more frequent in patients with single tumors than multifocal tumors. There were significant differences regarding hepatitis B status, Child Class, tumor number, grade, and TNM stage in cases where PMS2 methylation was detected. Our results suggest that methylation of genes involved in mismatch repair may be responsible in the pathogenesis of HCC, and evaluating changes in multiple genes in these pathways simultaneously would be more informative. Despite being a robust and relatively inexpensive method, the methylation-specific-multiplex ligated probe amplification assay could be more extensively applied with improvements in the currently intricate data analysis component.

  11. In vivo assessment of polydatin, a natural polyphenol compound, on arsenic-induced free radical overproduction, gene expression, and genotoxicity.

    Science.gov (United States)

    Arslan-Acaroz, Damla; Zemheri, Fahriye; Demirel, Hasan Huseyin; Kucukkurt, Ismail; Ince, Sinan; Eryavuz, Abdullah

    2018-01-01

    Arsenic (As) is a well-known contaminant of global groundwater. Its exposure causes several hazardous effects on animals and human via oxidative stress. The present study examined the effect of polydatin (PD) on free radical overproduction in rats exposed to As. Thirty-five male rats randomly allocated into five equal groups. To the control group, physiological saline was given orally and to the second group only 100 mg/L As was given by drinking water for 60 days. The other groups were treated with As (100 mg/L) and PD orally at 50, 100, and 200 mg/kg/day, respectively. Treatment with As enhanced malondialdehyde level but decreased glutathione level in blood, liver, kidney, brain, lung, and heart of rats. Also, As decreased superoxide dismutase and catalase activities of erythrocyte, liver, kidney, brain, lung, and heart in rats. Furthermore, As treatment gave rise to increased DNA damage and gene expressions of interleukin 1 beta (IL-1β), nuclear factor kappa beta (NFκB), p53, and tumor necrosis factor-α (TNF-α) in the lung, brain, kidney, and liver. However, treatment of PD ameliorated As-exposed lipid peroxidation, antioxidant enzymes activities, DNA damage, gene expressions, and histopathological changes in tissues. In conclusion, PD has a dose-dependent protective effect on lipid peroxidation and antioxidant defense mechanism in rats against As exposure.

  12. Molecular cloning of the human nucleotide-excision-repair gene ERCC4

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, L.H.; Brookman, K.W.; Weber, C.A.; Salazar, E.P. [Lawrence Livermore National Lab., CA (United States); Reardon, J.T.; Sancar, A. [Univ. of North Carolina, Chapel Hill, NC (United States); Deng, Z.; Siciliano, M.J. [Univ. of Texas Cancer Center, Houston, TX (United States)

    1994-07-19

    ERCC4 was previously identified in somatic cell hybrids as a human gene that corrects the nucleotide-excision-repair deficiency in mutant hamster cells. The cloning strategy for ERCC4 involved transfection of the repair-deficient hamster cell line UV41 with a human sCos-1 cosmid library derived from chromosome 16. Enhanced UV resistance was seen with one cosmid-library transformant and two secondary transformants of UV41. Cosmid clones carrying a functional ERCC4 gene were isolated from a library of a second transformant by selecting in Escherichia coli for expression of a linked neomycin-resistance gene that was present in the sCos-1 vector. The cosmids mapped to 16p13.13-p13.2, the location assigned to ERCC4 by using somatic cell hybrids. Upon transfection into UV41, six cosmid clones gave partial correction ranging from 30% to 64%, although all appeared to contain the complete gene. The capacity for in vitro excision of thymine dimers from a plasmid by transformant cell extracts correlated qualitatively with enhanced UV resistance.

  13. Mechanisms of skeletal muscle injury and repair revealed by gene expression studies in mouse models.

    Science.gov (United States)

    Warren, Gordon L; Summan, Mukesh; Gao, Xin; Chapman, Rebecca; Hulderman, Tracy; Simeonova, Petia P

    2007-07-15

    Common acute injuries to skeletal muscle can lead to significant pain and disability. The current therapeutic approaches for treating muscle injuries are dependent on the clinical severity but not on the type of injury. In the present studies, the pathophysiology and molecular pathways associated with two different types of skeletal muscle injury, one induced by direct destruction of muscle tissue (i.e. FI) and the other induced by a contractile overload (more specifically high-force eccentric contractions, i.e. CI) were compared side by side. Histopathological evaluation and measurements of muscle strength were accompanied by analyses of expression for 12 488 known genes at four time points ranging from 6 h to 7 days after injury. Real-time RT-PCR was used to confirm some of the injury type differences in the temporal profiles of gene expression. Our data revealed several pools of genes, including early induction of transcription, myogenic and stress-responsive factors, common for both types of injury as well as pools of genes expressed specifically with one of the injury types. Only CI activated a set of genes associated with the repair of impaired proteins and structures including genes related to apoptosis, whereas FI uniquely activated gene sets involved in extensive inflammatory responses, tissue remodelling, angiogenesis and myofibre/extracellular matrix synthesis. In conclusion, knowledge of the sets of genes associated specifically with the nature of the injury may have application for development of new strategies for acceleration of the recovery process in injured skeletal muscle.

  14. EZH2 suppresses the nucleotide excision repair in nasopharyngeal carcinoma by silencing XPA gene.

    Science.gov (United States)

    Huang, Yuxiang; Wang, Xuanyi; Niu, Xiaoshuang; Wang, Xiaoshen; Jiang, Rui; Xu, Tingting; Liu, Yong; Liang, Liping; Ou, Xiaomin; Xing, Xing; Li, Weiwei; Hu, Chaosu

    2017-02-01

    The enhancer of zeste homolog 2 (EZH2) is involved in a number of fundamental pathological processes of cancer. However, its role in DNA repair pathway is still unclear. Here, we have identified XPA as a novel target gene of EZH2 via a DNA repair pathway PCR array. XPA plays a pivot role in nucleotide excision repair (NER). The expression of XPA was significantly increased by EZH2 specific inhibitor GSK126 or lentiviral shEZH2 in nasopharyngeal carcinoma (NPC) CNE and 8F cell lines. Chromatin immunoprecipitation assay demonstrated that EZH2 catalyzes H3K27 trimethylation at the XPA promoters. Furthermore, we validated the negative correlation of EZH2 and XPA in a NPC tissue microarray by immunohistochemistry staining. We also found that high expression of EZH2 was positively correlated with advanced T, N, and AJCC stage of NPC; and low expression of XPA was positively correlated with advanced T and N stage. In NPC cell lines, increased XPA expression by EZH2 inhibition resulted in a more rapid removal of UVC induced 6-4PP- and CPD-DNA adducts, as well as enhanced efficiency of DNA repair after UVC irradiation as detected by the Comet assay and immunofluorescence staining of γH2Ax. Consistently, increased cell clonogenic survival, decreased apoptosis, and necrosis after UVC irradiation, and increased resistance to DNA damaging agent cisplatin was also observed in EZH2 inhibited cells. These results illustrate that EZH2 may promote carcinogenesis and cancer development of NPC by transcriptional repression of XPA gene and inactivation of NER pathway. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  15. Natural Antioxidants Against Arsenic-Induced Genotoxicity.

    Science.gov (United States)

    Kumar, Munesh; Lalit, Minakshi; Thakur, Rajesh

    2016-03-01

    Arsenic is present in water, soil, and air in organic as well as in inorganic forms. However, inorganic arsenic is more toxic than organic and can cause many diseases including cancers in humans. Its genotoxic effect is considered as one of its carcinogenic actions. Arsenic can cause DNA strand breaks, deletion mutations, micronuclei formation, DNA-protein cross-linking, sister chromatid exchange, and DNA repair inhibition. Evidences indicate that arsenic causes DNA damage by generation of reactive free radicals. Nutritional supplementation of antioxidants has been proven highly beneficial against arsenic genotoxicity in experimental animals. Recent studies suggest that antioxidants protect mainly by reducing excess free radicals via restoring the activities of cellular enzymatic as well as non-enzymatic antioxidants and decreasing the oxidation processes such as lipid peroxidation and protein oxidation. The purpose of this review is to summarize the recent literature on arsenic-induced genotoxicity and its mitigation by naturally derived antioxidants in various biological systems.

  16. Altered Gene Expressions and Cytogenetic Repair Efficiency in Cells with Suppressed Expression of XPA after Proton Exposure

    Science.gov (United States)

    Zhang, Ye; Rohde, Larry H.; Gridley, Daila S.; Mehta, Satish K.; Pierson, Duane L.; Wu, Honglu

    2009-01-01

    Cellular responses to damages from ionizing radiation (IR) exposure are influenced not only by the genes involved in DNA double strand break (DSB) repair, but also by non- DSB repair genes. We demonstrated previously that suppressed expression of several non-DSB repair genes, such as XPA, elevated IR-induced cytogenetic damages. In the present study, we exposed human fibroblasts that were treated with control or XPA targeting siRNA to 250 MeV protons (0 to 4 Gy), and analyzed chromosome aberrations and expressions of genes involved in DNA repair. As expected, after proton irradiation, cells with suppressed expression of XPA showed a significantly elevated frequency of chromosome aberrations compared with control siRNA treated (CS) cells. Protons caused more severe DNA damages in XPA knock-down cells, as 36% cells contained multiple aberrations compared to 25% in CS cells after 4Gy proton irradiation. Comparison of gene expressions using the real-time PCR array technique revealed that expressions of p53 and its regulated genes in irradiated XPA suppressed cells were altered similarly as in CS cells, suggesting that the impairment of IR induced DNA repair in XPA suppressed cells is p53-independent. Except for XPA, which was more than 2 fold down regulated in XPA suppressed cells, several other DNA damage sensing and repair genes (GTSE1, RBBP8, RAD51, UNG and XRCC2) were shown a more than 1.5 fold difference between XPA knock-down cells and CS cells after proton exposure. The possible involvement of these genes in the impairment of DNA repair in XPA suppressed cells will be further investigated.

  17. A Phytoremediation Strategy for Arsenic

    Energy Technology Data Exchange (ETDEWEB)

    Meagher, Richard B.

    2005-06-01

    A Phytoremediation Strategy for Arsenic Progress Report May, 2005 Richard B. Meagher Principal Investigator Arsenic pollution affects the health of several hundred millions of people world wide, and an estimated 10 million Americans have unsafe levels of arsenic in their drinking water. However, few environmentally sound remedies for cleaning up arsenic contaminated soil and water have been proposed. Phytoremediation, the use of plants to extract and sequester environmental pollutants, is one new technology that offers an ecologically sound solution to a devastating problem. We propose that it is less disruptive to the environment to harvest and dispose of several thousand pounds per acre of contaminated aboveground plant material, than to excavate and dispose of 1 to 5 million pounds of contaminated soil per acre (assumes contamination runs 3 ft deep). Our objective is to develop a genetics-based phytoremediation strategy for arsenic removal that can be used in any plant species. This strategy requires the enhanced expression of several transgenes from diverse sources. Our working hypothesis is that organ-specific expression of several genes controlling the transport, electrochemical state, and binding of arsenic will result in the efficient extraction and hyperaccumulation of arsenic into aboveground plant tissues. This hypothesis is supported by theoretical arguments and strong preliminary data. We proposed six Specific Aims focused on testing and developing this arsenic phytoremediation strategy. During the first 18 months of the grant we made significant progress on five Specific Aims and began work on the sixth as summarized below. Specific Aim 1: Enhance plant arsenic resistance and greatly expand sinks for arsenite by expressing elevated levels of thiol-rich, arsenic-binding peptides. Hyperaccumulation of arsenic depends upon making plants that are both highly tolerant to arsenic and that have the capacity to store large amounts of arsenic aboveground

  18. Rapid assessment of repair of ultraviolet DNA damage with a modified host-cell reactivation assay using a luciferase reporter gene and correlation with polymorphisms of DNA repair genes in normal human lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Qiao Yawei; Spitz, Margaret R.; Guo Zhaozheng; Hadeyati, Mohammad; Grossman, Lawrence; Kraemer, Kenneth H.; Wei Qingyi

    2002-11-30

    As DNA repair plays an important role in genetic susceptibility to cancer, assessment of the DNA repair phenotype is critical for molecular epidemiological studies of cancer. In this report, we compared use of the luciferase (luc) reporter gene in a host-cell reactivation (HCR) (LUC) assay of repair of ultraviolet (UV) damage to DNA to use of the chloramphenicol (cat) gene-based HCR (CAT) assay we used previously for case-control studies. We performed both the assays on cryopreserved lymphocytes from 102 healthy non-Hispanic white subjects. There was a close correlation between DNA repair capacity (DRC) as measured by the LUC and CAT assays. Although these two assays had similar variation, the LUC assay was faster and more sensitive. We also analyzed the relationship between DRC and the subjects' previously determined genotypes for four polymorphisms of two nucleotide-excision repair (NER) genes (in intron 9 of xeroderma pigmentosum (XP) C and exons 6, 10 and 23 of XPD) and one polymorphism of a base-excision repair gene in exon 10 of X-ray complementing group 1 (XRCC1). The DRC was significantly lower in subjects homozygous for one or more polymorphisms of the two NER genes than in subjects with other genotypes (P=0.010). In contrast, the polymorphic XRCC1 allele had no significant effect on DRC. These results suggest that the post-UV LUC assay measures NER phenotype and that polymorphisms of XPC and XPD genes modulate DRC. For population studies of the DNA repair phenotype, many samples need to be evaluated, and so the LUC assay has several advantages over the CAT assay: the LUC assay was more sensitive, had less variation, was not radioactive, was easier to perform, and required fewer cryopreserved cells. These features make the LUC-based HCR assay suitable for molecular epidemiological studies.

  19. Expression of DNA repair genes in burned skin exposed to low-level red laser.

    Science.gov (United States)

    Trajano, Eduardo Tavares Lima; Mencalha, Andre Luiz; Monte-Alto-Costa, Andréa; Pôrto, Luís Cristóvão; de Souza da Fonseca, Adenilson

    2014-11-01

    Although red laser lights lie in the region of non-ionizing radiations in the electromagnetic spectrum, there are doubts whether absorption of these radiations causes lesions in the DNA molecule. Our aim was to investigate the expression of the genes involved with base excision and nucleotide excision repair pathways in skin tissue submitted to burn injury and exposed to low-level red laser. Wistar rats were divided as follows: control group-rats burned and not irradiated, laser group-rats burned and irradiated 1 day after injury for five consecutive days, and later laser group-rats injured and treated 4 days after injury for five consecutive days. Irradiation was performed according to a clinical protocol (20 J/cm(2), 100 mW, continuous wave emission mode). The animals were sacrificed on day 10, and scarred tissue samples were withdrawn for total RNA extraction, complementary DNA (cDNA) synthesis, and evaluation of gene expression by quantitative polymerase chain reaction. Low-level red laser exposure (1) reduces the expression of APE1 messenger (mRNA), (2) increases the expression of OGG1 mRNA, (3) reduces the expression of XPC mRNA, and (4) increases the expression of XPA mRNA both in laser and later laser groups. Red laser exposure at therapeutic fluences alters the expression of genes related to base excision and nucleotide excision pathways of DNA repair during wound healing of burned skin.

  20. The democratization of gene editing: Insights from site-specific cleavage and double-strand break repair.

    Science.gov (United States)

    Jasin, Maria; Haber, James E

    2016-08-01

    DNA double-strand breaks (DSBs) are dangerous lesions that if not properly repaired can lead to genomic change or cell death. Organisms have developed several pathways and have many factors devoted to repairing DSBs, which broadly occurs by homologous recombination, which relies on an identical or homologous sequence to template repair, or nonhomologous end-joining. Much of our understanding of these repair mechanisms has come from the study of induced DNA cleavage by site-specific endonucleases. In addition to their biological role, these cellular pathways can be co-opted for gene editing to study gene function or for gene therapy or other applications. While the first gene editing experiments were done more than 20 years ago, the recent discovery of RNA-guided endonucleases has simplified approaches developed over the years to make gene editing an approach that is available to the entire biomedical research community. Here, we review DSB repair mechanisms and site-specific cleavage systems that have provided insight into these mechanisms and led to the current gene editing revolution. Copyright © 2016. Published by Elsevier B.V.

  1. The Democratization of Gene Editing: Insights from site-specific cleavage and double-strand break repair

    Science.gov (United States)

    Jasin, Maria; Haber, James E.

    2017-01-01

    DNA double-strand breaks (DSBs) are dangerous lesions that if not properly repaired can lead to genomic change or cell death. Organisms have developed several pathways and have many factors devoted to repairing DSBs, which broadly occur by homologous recombination that relies on an identical or homologous sequence to template repair, or nonhomologous end-joining. Much of our understanding of these repair mechanisms has come from the study of induced DNA cleavage by site-specific endonucleases. In addition to their biological role, these cellular pathways can be co-opted for gene editing to study gene function or for gene therapy or other applications. While the first gene editing experiments were done more than 20 years ago, the recent discovery of RNA-guided endonucleases has simplified approaches developed over the years to make gene editing an approach that is available to the entire biomedical research community. Here, we review DSB repair mechanisms and site-specific cleavage systems that have provided insight into these mechanisms and led to the current gene editing revolution. PMID:27261202

  2. Nucleotide Excision Repair in Cellular Chromatin: Studies with Yeast from Nucleotide to Gene to Genome

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    Simon Reed

    2012-09-01

    Full Text Available Here we review our development of, and results with, high resolution studies on global genome nucleotide excision repair (GGNER in Saccharomyces cerevisiae. We have focused on how GGNER relates to histone acetylation for its functioning and we have identified the histone acetyl tranferase Gcn5 and acetylation at lysines 9/14 of histone H3 as a major factor in enabling efficient repair. We consider results employing primarily MFA2 as a model gene, but also those with URA3 located at subtelomeric sequences. In the latter case we also see a role for acetylation at histone H4. We then go on to outline the development of a high resolution genome-wide approach that enables one to examine correlations between histone modifications and the nucleotide excision repair (NER of UV-induced cyclobutane pyrimidine dimers throughout entire genomes. This is an approach that will enable rapid advances in understanding the complexities of how compacted chromatin in chromosomes is processed to access DNA damage and then returned to its pre-damaged status to maintain epigenetic codes.

  3. Subcellular distribution, modulation of antioxidant and stress-related genes response to arsenic in Brassica napus L.

    Science.gov (United States)

    Farooq, Muhammad A; Gill, Rafaqat A; Ali, Basharat; Wang, Jian; Islam, Faisal; Ali, Shafaqat; Zhou, Weijun

    2016-03-01

    Arsenic (As) is an environmental toxin pollutant that affects the numerous physiological processes of plants. In present study, two Brassica napus L. cultivars were subjected to various concentrations (0, 50, 100, and 200 µM) of As for 14 days, plants were examined for As subcellular distribution, photosynthesis parameters, oxidative stress, and ultrastructural changes under As-stress. Differential fraction analysis showed that significant amount of As was accumulated in the cell wall as compared to other organelles. Decline in photosynthetic efficiency under As stress was observed in term of reduced pigment contents and gas exchange parameters. Differential responses of antioxidants at both enzymatic and gene levels to higher As stress were more pronounced in cultivar ZS 758 as compared to Zheda 622. The qRT-PCR analysis showed that heat shock protein 90 (Hsp90) and metallothionein were over-expressed in As stressed B. napus plants. Disorganization of cell structure and the damages in different organelles were some of the obvious variations in cultivar Zheda 622 as compared to ZS 758.

  4. XRCC1 Arg194Trp and Arg399Gln polymorphisms and arsenic methylation capacity are associated with urothelial carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Chien-I [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Huang, Ya-Li [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Chen, Wei-Jen [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Shiue, Horng-Sheng [Department of Chinese Medicine, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan (China); Huang, Chao-Yuan; Pu, Yeong-Shiau [Department of Urology, National Taiwan University Hospital, College of Medicine National Taiwan University, Taipei, Taiwan (China); Lin, Ying-Chin [Department of Family Medicine, Shung Ho Hospital, Taipei Medical University, New Taipei, Taiwan (China); Department of Health Examination, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan (China); Division of Family Medicine, School of Medicine, Taipei Medical University, Taipei, Taiwan (China); Hsueh, Yu-Mei, E-mail: ymhsueh@tmu.edu.tw [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China)

    2014-09-15

    The association between DNA repair gene polymorphisms and bladder cancer has been widely studied. However, few studies have examined the correlation between urothelial carcinoma (UC) and arsenic or its metabolites. The aim of this study was to examine the association between polymorphisms of the DNA repair genes, XRCC1 Arg194Trp, XRCC1 Arg399Gln, XRCC3 Thr241Met, and XPD Lys751Gln, with urinary arsenic profiles and UC. To this end, we conducted a hospital-based case–control study with 324 UC patients and 647 age- and gender-matched non-cancer controls. Genomic DNA was used to examine the genotype of XRCC1 Arg194Trp, XRCC1 Arg399Gln, XRCC3 Thr241Met, and XPD Lys751Gln by PCR-restriction fragment length polymorphism analysis (PCR-RFLP). Urinary arsenic profiles were measured by high performance liquid chromatography (HPLC) linked with hydride generator and atomic absorption spectrometry. The XRCC1 399 Gln/Gln and 194 Arg/Trp and Trp/Trp genotypes were significantly related to UC, and the odds ratio (OR) and 95% confidence interval (95%CI) were 1.68 (1.03–2.75) and 0.66 (0.48–0.90), respectively. Participants with higher total urinary arsenic levels, a higher percentage of inorganic arsenic (InAs%) and a lower percentage of dimethylarsinic acid (DMA%) had a higher OR of UC. Participants carrying XRCC1 risk diplotypes G-C/G-C, A-C/A-C, and A-T/G-T, and who had higher total arsenic levels, higher InAs%, or lower DMA% compared to those with other XRCC1 diplotypes had a higher OR of UC. Our results suggest that the XRCC1 399 Gln/Gln and 194 Arg/Arg DNA repair genes play an important role in poor arsenic methylation capacity, thereby increasing the risk of UC in non-obvious arsenic exposure areas. - Highlights: • The XRCC1 399Gln/Gln genotype was significantly associated with increased OR of UC. • The XRCC1 194 Arg/Trp and Trp/Trp genotype had a significantly decreased OR of UC. • Combined effect of the XRCC1 genotypes and poor arsenic methylation capacity on

  5. Human DNA repair genes possess potential G-quadruplex sequences in their promoters and 5`-untranslated regions.

    Science.gov (United States)

    Fleming, Aaron M; Zhu, Judy; Ding, Yun; Visser, Joshua A; Zhu, Julia; Burrows, Cynthia J

    2018-01-10

    The cellular response to oxidative stress includes transcriptional changes, particularly for genes involved in DNA repair. Recently, our laboratory demonstrated that oxidation of 2`-deoxyguanosine (G) to 8-oxo-7,8-dihydro-2`-deoxyguanosine (OG) in G-rich potential G-quadruplex sequences (PQSs) in gene promoters impacts the level of gene expression up or down depending on the position of the PQS in the promoter. In the present report, bioinformatic analysis found that the 390 human DNA repair genes in the genome ontology initiative harbor 2,936 PQSs in their promoters and 5`-untranslated regions (5`-UTRs). The average density of PQSs in human DNA repair genes was found to be nearly twofold greater than the average density of PQSs in all coding and non-coding human genes (7.5 vs. 4.3 per gene). The distribution of the PQSs in the DNA repair genes on the non-transcribed (coding) vs. transcribed strands reflects that of PQSs in all human genes. Next, literature data were interrogated to select 30 PQSs to catalog their ability to adopt G-quadruplex (G4) folds in vitro using five different experimental tests. The G4 characterization experiments concluded that 26 of the 30 sequences could adopt G4 topologies in solution. Last, four PQSs were synthesized into the promoter of a luciferase plasmid and co-transfected with the G4-specific ligands pyridostatin, Phen-DC3, or BRACO-19 in human cells to determine whether the PQSs could adopt G4 folds. The cell studies identified changes in luciferase expression when the G4 ligands were present, and the magnitude of the expression changes dependent on the PQS and the coding vs. template strand on which the sequence resided. Our studies demonstrate PQSs exist at a high density in human DNA repair gene promoters and a subset of the identified sequences fold in vitro and in vivo.

  6. Haplotype analyses of DNA repair gene polymorphisms and their role in ulcerative colitis.

    Directory of Open Access Journals (Sweden)

    Avinash Bardia

    Full Text Available Ulcerative colitis (UC is a major clinical form of inflammatory bowel disease. UC is characterized by mucosal inflammation limited to the colon, always involving the rectum and a variable extent of the more proximal colon in a continuous manner. Genetic variations in DNA repair genes may influence the extent of repair functions, DNA damage, and thus the manifestations of UC. This study thus evaluated the role of polymorphisms of the genes involved in DNA repair mechanisms. A total of 171 patients and 213 controls were included. Genotyping was carried out by ARMS PCR and PCR-RFLP analyses for RAD51, XRCC3 and hMSH2 gene polymorphisms. Allelic and genotypic frequencies were computed in both control & patient groups and data was analyzed using appropriate statistical tests. The frequency of 'A' allele of hMSH2 in the UC group caused statistically significant increased risk for UC compared to controls (OR 1.64, 95% CI 1.16-2.31, p = 0.004. Similarly, the CT genotype of XRCC3 gene was predominant in the UC group and increased the risk for UC by 1.75 fold compared to controls (OR 1.75, 95% CI 1.15-2.67, p = 0.03, further confirming the risk of 'T' allele in UC. The GC genotype frequency of RAD51 gene was significantly increased (p = 0.02 in the UC group (50.3% compared to controls (38%. The GC genotype significantly increased the risk for UC compared to GG genotype by 1.73 fold (OR 1.73, 95% CI 1.14-2.62, p = 0.02 confirming the strong association of 'C' allele with UC. Among the controls, the SNP loci combination of hMSH2:XRCC3 were in perfect linkage. The GTC and ACC haplotypes were found to be predominant in UC than controls with a 2.28 and 2.93 fold significant increase risk of UC.

  7. Role of APC and DNA mismatch repair genes in the development of colorectal cancers

    Directory of Open Access Journals (Sweden)

    Roy Deodutta

    2003-12-01

    Full Text Available Abstract Colorectal cancer is the third most common cause of cancer-related death in both men and women in the western hemisphere. According to the American Cancer Society, an estimated 105,500 new cases of colon cancer with 57,100 deaths will occur in the U.S. in 2003, accounting for about 10% of cancer deaths. Among the colon cancer patients, hereditary risk contributes approximately 20%. The main inherited colorectal cancers are the familial adenomatous polyposis (FAP and the hereditary nonpolyposis colorectal cancers (HNPCC. The FAP and HNPCC are caused due to mutations in the adenomatous polyposis coli (APC and DNA mismatch repair (MMR genes. The focus of this review is to summarize the functions of APC and MMR gene products in the development of colorectal cancers.

  8. BRD4 Promotes DNA Repair and Mediates the Formation of TMPRSS2-ERG Gene Rearrangements in Prostate Cancer

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    Xiangyi Li

    2018-01-01

    Full Text Available BRD4 belongs to the bromodomain and extraterminal (BET family of chromatin reader proteins that bind acetylated histones and regulate gene expression. Pharmacological inhibition of BRD4 by BET inhibitors (BETi has indicated antitumor activity against multiple cancer types. We show that BRD4 is essential for the repair of DNA double-strand breaks (DSBs and mediates the formation of oncogenic gene rearrangements by engaging the non-homologous end joining (NHEJ pathway. Mechanistically, genome-wide DNA breaks are associated with enhanced acetylation of histone H4, leading to BRD4 recruitment, and stable establishment of the DNA repair complex. In support of this, we also show that, in clinical tumor samples, BRD4 protein levels are negatively associated with outcome after prostate cancer (PCa radiation therapy. Thus, in addition to regulating gene expression, BRD4 is also a central player in the repair of DNA DSBs, with significant implications for cancer therapy.

  9. Toll pathway is required for wound-induced expression of barrier repair genes in the Drosophila epidermis

    Science.gov (United States)

    Capilla, Amalia; Karachentsev, Dmitry; Patterson, Rachel A.; Hermann, Anita; Juarez, Michelle T.; McGinnis, William

    2017-01-01

    The epidermis serves as a protective barrier in animals. After epidermal injury, barrier repair requires activation of many wound response genes in epidermal cells surrounding wound sites. Two such genes in Drosophila encode the enzymes dopa decarboxylase (Ddc) and tyrosine hydroxylase (ple). In this paper we explore the involvement of the Toll/NF-κB pathway in the localized activation of wound repair genes around epidermal breaks. Robust activation of wound-induced transcription from ple and Ddc requires Toll pathway components ranging from the extracellular ligand Spätzle to the Dif transcription factor. Epistasis experiments indicate a requirement for Spätzle ligand downstream of hydrogen peroxide and protease function, both of which are known activators of wound-induced transcription. The localized activation of Toll a few cell diameters from wound edges is reminiscent of local activation of Toll in early embryonic ventral hypoderm, consistent with the hypothesis that the dorsal–ventral patterning function of Toll arose from the evolutionary cooption of a morphogen-responsive function in wound repair. Furthermore, the combinatorial activity of Toll and other signaling pathways in activating epidermal barrier repair genes can help explain why developmental activation of the Toll, ERK, or JNK pathways alone fail to activate wound repair loci. PMID:28289197

  10. Cystic fibrosis gene repair: correction of ΔF508 using ZFN and CRISPR/Cas9 guide RNA gene editing tools

    OpenAIRE

    Hollywood, Jennifer

    2013-01-01

    Cystic Fibrosis (CF) is an autosomal recessive monogenic disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene with the ΔF508 mutation accounting for approximately 70% of all CF cases worldwide. This thesis investigates whether existing zinc finger nucleases designed in this lab and CRISPR/gRNAs designed in this thesis can mediate efficient homology-directed repair (HDR) with appropriate donor repair plasmids to correct CF-causing mutations in a C...

  11. DNA excision repair and double-strand break repair gene polymorphisms and the level of chromosome aberration in children with long-term exposure to radon.

    Science.gov (United States)

    Larionov, Aleksey V; Sinitsky, Maxim Y; Druzhinin, Vladimir G; Volobaev, Valentin P; Minina, Varvara I; Asanov, Maxim A; Meyer, Alina V; Tolochko, Tatiana A; Kalyuzhnaya, Ekaterina E

    2016-08-01

    To study polymorphic variants of repair genes in people affected by long-term exposure to radon. The chromosome aberration frequency in peripheral blood lymphocytes was used as the biological marker of genotoxicity. Genotyping of 12 single nucleotide polymorphisms in DNA repair genes (APE, XRCC1, OGG1, ADPRT, XpC, XpD, XpG, Lig4 and NBS1) was performed in children with long-term resident exposure to radon. Quantification of the aberrations was performed using light microscopy. The total frequency of aberrations was increased in carriers of the G/G genotype for the XpD gene (rs13181) polymorphism in recessive model confirmed by the results of ROC-analysis ('satisfactory predictor', AUC = 0.609). Single chromosome fragments frequency was increased in carriers of the G/G genotype in comparison with the T/T genotype. In respect to the total frequency of aberrations, the G/G genotype for the XpG gene (rs17655) polymorphism was also identified as a 'satisfactory predictor' (AUC = 0.605). Carriers of the T/C genotype for the ADPRT gene (rs1136410) polymorphism were characterized by an increased level of single fragments relative to the T/T genotype. The relationships with several types of cytogenetic damage suggest these three SNP (rs13181, rs17655 and rs1136410) may be considered radiosensitivity markers.

  12. Cockayne Syndrome exhibits dysregulation of p21 and other gene products that may be independent of transcription coupled repair

    Science.gov (United States)

    Cleaver, J.E.; Hefner, E.; Laposa, R.R.; Karentz, D.

    2007-01-01

    Cockayne syndrome (CS) is a progressive childhood neurodegenerative disorder associated with a DNA repair defect caused by mutations in either of two genes, CSA and CSB. These genes are involved in nucleotide excision repair (NER) of DNA damage from ultraviolet (UV) light, other bulky chemical adducts and reactive oxygen in transcriptionally active genes (transcription coupled repair, TCR). For a long period it has been assumed that the symptoms of CS patients are all due to reduced TCR of endogenous DNA damage in the brain, together with unexplained unique sensitivity of specific neural cells in the cerebellum. Not all the symptoms of CS patients are however easily related to repair deficiencies, so we hypothesize that there are additional pathways relevant to the disease, particularly those that are downstream consequences of a common defect in the E3 ubiquitin ligase associated with the CSA and CSB gene products. We have found that the CSB defect results in altered expression of anti-angiogenic and cell cycle genes and proteins at the level of both gene expression and protein lifetime. We find an over-abundance of p21 due to reduced protein turnover, possibly due to the loss of activity of the CSA/CSB E3 ubiquitylation pathway. Increased levels of p21 can result in growth inhibition, reduced repair from the p21-PCNA interaction, and increased generation of reactive oxygen. Consistent with increased reactive ozygen levels we find that CS-A and -B cells grown under ambient oxygen show increased DNA breakage, as compared to xeroderma pigmentosum cells. Thus the complex symptoms of CS may be due to multiple, independent downstream targets of the E3 ubiquitylation system that results in increased DNA damage, reduced transcription coupled repair, and inhibition of cell cycle progression and growth. PMID:17055654

  13. Horizontal gene transfer regulation in bacteria as a "spandrel" of DNA repair mechanisms.

    Directory of Open Access Journals (Sweden)

    Saliou Fall

    Full Text Available Horizontal gene transfer (HGT is recognized as the major force for bacterial genome evolution. Yet, numerous questions remain about the transferred genes, their function, quantity and frequency. The extent to which genetic transformation by exogenous DNA has occurred over evolutionary time was initially addressed by an in silico approach using the complete genome sequence of the Ralstonia solanacearum GMI1000 strain. Methods based on phylogenetic reconstruction of prokaryote homologous genes families detected 151 genes (13.3% of foreign origin in the R. solanacearum genome and tentatively identified their bacterial origin. These putative transfers were analyzed in comparison to experimental transformation tests involving 18 different genomic DNA positions in the genome as sites for homologous or homeologous recombination. Significant transformation frequency differences were observed among these positions tested regardless of the overall genomic divergence of the R. solanacearum strains tested as recipients. The genomic positions containing the putative exogenous DNA were not systematically transformed at the highest frequencies. The two genomic "hot spots", which contain recA and mutS genes, exhibited transformation frequencies from 2 to more than 4 orders of magnitude higher than positions associated with other genes depending on the recipient strain. These results support the notion that the bacterial cell is equipped with active mechanisms to modulate acquisition of new DNA in different genomic positions. Bio-informatics study correlated recombination "hot-spots" to the presence of Chi-like signature sequences with which recombination might be preferentially initiated. The fundamental role of HGT is certainly not limited to the critical impact that the very rare foreign genes acquired mainly by chance can have on the bacterial adaptation potential. The frequency to which HGT with homologous and homeologous DNA happens in the environment

  14. Yeast DNA-repair gene RAD14 encodes a zinc metalloprotein with affinity for ultraviolet-damaged DNA.

    OpenAIRE

    Guzder, S N; Sung, P; Prakash, L; Prakash, S

    1993-01-01

    Xeroderma pigmentosum (XP) patients suffer from a high incidence of skin cancers due to a defect in excision repair of UV light-damaged DNA. Of the seven XP complementation groups, A-G, group A represents a severe and frequent form of the disease. The Saccharomyces cerevisiae RAD14 gene is a homolog of the XP-A correcting (XPAC) gene. Like XP-A cells, rad14-null mutants are defective in the incision step of excision repair of UV-damaged DNA. We have purified RAD14 protein to homogeneity from ...

  15. Enzymatic repair of selected cross-linked homoduplex molecules enhances nuclear gene rescue from Pompeii and Herculaneum remains.

    Science.gov (United States)

    Di Bernardo, Giovanni; Del Gaudio, Stefania; Cammarota, Marcella; Galderisi, Umberto; Cascino, Antonino; Cipollaro, Marilena

    2002-02-15

    Ancient DNA (aDNA) samples extracted from the bone remains of six equids buried by the Vesuvius eruption in 79 AD were investigated to test pre-amplification and enzymatic repair procedures designed to enhance the rescue of nuclear genes. The extracts, which proved all positive for Equidae mtDNA amplification, proved positive only four times out of 18 when tested for single-copy Equidae nuclear genes (epsilon globin, p53 and gamma interferon). Pre-amplification did not change the number of retrieved aDNA sequences but 10 times out of 14 enzymatic repair restored the amplifiability of the genes analysed, proving that repair increases the rate of successful rescue from 22 to alpha(lambda)mu(omicron)sigma(tau) 80%. These findings support the hypothesis that some of these cross-linked aDNA molecules, which are not completely separated when DNA is extracted under denaturing conditions, become homoduplex substrates for Pol I and/or T4 ligase action upon renaturation. aDNA authenticity is proved by the homology of the nucleotide sequences of loci tested to the corresponding modern Equidae sequences. Data also indicate that cross-linked homoduplex molecules selected by denaturation of the extract are repaired without any chimera formation. The general features of aDNA amplification with and without denaturation and enzymatic repair are discussed.

  16. Transcription pattern of p53-targeted DNA repair genes in the hypoxia-tolerant subterranean mole rat Spalax.

    Science.gov (United States)

    Shams, Imad; Malik, Assaf; Manov, Irena; Joel, Alma; Band, Mark; Avivi, Aaron

    2013-04-12

    The tumor suppressor gene p53 induces growth arrest and/or apoptosis in response to DNA damage/hypoxia. Inactivation of p53 confers a selective advantage to tumor cells under a hypoxic microenvironment during tumor progression. The subterranean blind mole rat, Spalax, spends its life underground at low-oxygen tensions, hence developing a wide range of respiratory/molecular adaptations to hypoxic stress, including critical changes in p53 structure and signaling pathway. The highly conserved p53 Arg(R)-172 is substituted by lysine (K) in Spalax, identical with a tumor-associated mutation. Functionality assays revealed that Spalax p53 is unable to activate apoptotic target genes but is still capable of activating cell cycle arrest genes. Furthermore, we have shown that the transcription patterns of representative p53-induced genes (Apaf1 and Mdm2) in Spalax are influenced by hypoxia. Cell cycle arrest allows the cells to repair DNA damage via different DNA repair genes. We tested the transcription pattern of three p53-related DNA repair genes (p53R2, Mlh1, and Msh2) under normoxia and short-acute hypoxia in Spalax, C57BL/6 wild-type mice, and two strains of mutant C57BL/6 mice, each carrying a different mutation at the R172 position. Our results show that while wild-type/mutant mice exhibit strong hypoxia-induced reductions of repair gene transcript levels, no such inhibition is found in Spalax under hypoxia. Moreover, unlike mouse p53R2, Spalax p53R2 transcript levels are strongly elevated under hypoxia. These results suggest that critical repair functions, which are known to be inhibited under hypoxia in mice, remain active in Spalax, as part of its unique hypoxia tolerance mechanisms. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Clustered Mutation Signatures Reveal that Error-Prone DNA Repair Targets Mutations to Active Genes.

    Science.gov (United States)

    Supek, Fran; Lehner, Ben

    2017-07-27

    Many processes can cause the same nucleotide change in a genome, making the identification of the mechanisms causing mutations a difficult challenge. Here, we show that clustered mutations provide a more precise fingerprint of mutagenic processes. Of nine clustered mutation signatures identified from >1,000 tumor genomes, three relate to variable APOBEC activity and three are associated with tobacco smoking. An additional signature matches the spectrum of translesion DNA polymerase eta (POLH). In lymphoid cells, these mutations target promoters, consistent with AID-initiated somatic hypermutation. In solid tumors, however, they are associated with UV exposure and alcohol consumption and target the H3K36me3 chromatin of active genes in a mismatch repair (MMR)-dependent manner. These regions normally have a low mutation rate because error-free MMR also targets H3K36me3 chromatin. Carcinogens and error-prone repair therefore redistribute mutations to the more important regions of the genome, contributing a substantial mutation load in many tumors, including driver mutations. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. ABCB5 is a limbal stem cell gene required for corneal development and repair

    Science.gov (United States)

    Ksander, Bruce R.; Kolovou, Paraskevi E.; Wilson, Brian J.; Saab, Karim R.; Guo, Qin; Ma, Jie; McGuire, Sean P.; Gregory, Meredith S.; Vincent, William J. B.; Perez, Victor L.; Cruz-Guilloty, Fernando; Kao, Winston W. Y.; Call, Mindy K.; Tucker, Budd A.; Zhan, Qian; Murphy, George F.; Lathrop, Kira L.; Alt, Clemens; Mortensen, Luke J.; Lin, Charles P.; Zieske, James D.; Frank, Markus H.; Frank, Natasha Y.

    2014-01-01

    Corneal epithelial homeostasis and regeneration are sustained by limbal stem cells (LSCs)1–3, and LSC deficiency is a major cause of blindness worldwide4. Transplantation is often the only therapeutic option available to patients with LSC deficiency. However, while transplant success depends foremost on LSC frequency within grafts5, a gene allowing for prospective LSC enrichment has not been identified so far5. Here we show that ATP-binding cassette, sub-family B, member 5 (ABCB5)6,7 marks LSCs and is required for LSC maintenance, corneal development and repair. Furthermore, we demonstrate that prospectively isolated human or murine ABCB5-positive LSCs possess the exclusive capacity to fully restore the cornea upon grafting to LSC-deficient mice in xenogeneic or syngeneic transplantation models. ABCB5 is preferentially expressed on label-retaining LSCs2 in mice and p63α-positive LSCs8 in humans. Consistent with these findings, ABCB5-positive LSC frequency is reduced in LSC-deficient patients. Abcb5 loss of function in Abcb5 knockout mice causes depletion of quiescent LSCs due to enhanced proliferation and apoptosis, and results in defective corneal differentiation and wound healing. Our results from gene knockout studies, LSC tracing and transplantation models, as well as phenotypic and functional analyses of human biopsy specimens, provide converging lines of evidence that ABCB5 identifies mammalian LSCs. Identification and prospective isolation of molecularly defined LSCs with essential functions in corneal development and repair has important implications for the treatment of corneal disease, particularly corneal blindness due to LSC deficiency. PMID:25030174

  19. [Lentiviral vector-mediated RNA interfere gene Nogo receptor to repair spinal cord injury].

    Science.gov (United States)

    Lü, Bi-tao; Yuan, Wen; Xu, Sheng-ming

    2010-10-15

    To evaluate the effects of lentiviral vector-mediated RNA interfere gene Nogo receptor (NgR) of rat cortical neurons in repairing spinal cord injury. The recombinant-lentiviral vector with small inferring RNA siNgR199 which had been constructed was transfected into rat cortical neuron cells in vitro in 3 multiplicity of infection (MOI). The infection rate was determined with fluorescent microscope, and the target gene was detected by PCR analysis. Then, the recombinant was injected into the cortical motor area of the rats with severe spinal cord injury, and the saline was also injected into other rats with severe spinal cord injury as a match control. The functional recovery of the rats' hindlimb was assessed using BBB score and the nerve fiber of the injured region was observed by nerve tracing. The rate of recombinant infecting rat cortical neuron in vitro exceeded 99%. PCR analysis confirmed that the effect of lentiviral vector-mediated RNA interfering gene NgR of rat cortical neurons in vitro was 61%. Although all rats with spinal cord injury were observed to have the hindlimb functional recovery, these rats injected with recombinant had better hindlimb functional recovery than others showing by more BBB score (P vector with siNgR199 which had been constructed is able to promote the growth of nerve fiber and the functional recovery of the rats' hindlimb.

  20. Allelic variants of XRCC1 and XRCC3 repair genes and susceptibility of oral cancer in Brazilian patients

    DEFF Research Database (Denmark)

    Dos Reis, Mariana Bisarro; Losi-Guembarovski, Roberta; de Souza Fonseca Ribeiro, Enilze Maria

    2013-01-01

    genes have been found to be associated with oral cancer. The aim of this study was to investigate the relationship between the presence of allelic variants Arg194Trp (rs:1799782) and Arg399Gln (rs: 25487) of XRCC1 gene and Thr241Met (rs: 861539) of XRCC3 gene and susceptibility to oral cancer. We also...... variants of the XRCC1 gene within codon 194 (OR 0.82, 95% CI: 0.44-1.51) and codon 399 (OR 0.94, 95% CI: 0.59-1.50) and within the XRCC3 gene (OR 0.72; 95% CI: 0.45-1.16) were not associated with an increased risk of oral cancer. A combinational analysis of SNPs in both genes indicated no association......BACKGROUND: The capacity for DNA repair is essential in maintaining cellular functions and homeostasis; however, this capacity can be altered based on DNA sequence variations in DNA repair genes, which may contribute to the onset of cancer. Many single-nucleotide polymorphisms (SNPs) in repair...

  1. Biallelic germline mutations of mismatch-repair genes: a possible cause for multiple pediatric malignancies.

    Science.gov (United States)

    Poley, Jan-Werner; Wagner, Anja; Hoogmans, Monique M C P; Menko, Fred H; Tops, Carli; Kros, Johan M; Reddingius, Roel E; Meijers-Heijboer, Hanne; Kuipers, Ernst J; Dinjens, Winand N M

    2007-06-01

    Heterozygous defects in mismatch-repair (MMR) genes cause hereditary nonpolyposis colorectal cancer (HNPCC). In this syndrome, tumors typically arise from age 25 years onward. Case reports have shown that homozygosity or compound heterozygosity for MMR gene mutations can cause multiple tumors in childhood, sometimes combined with neurofibromatosis type I (NF1)-like features. Therefore, the authors studied the role of homozygosity or compound heterozygosity (CZ) for MMR gene defects in children with multiple primary tumors. A database that contained all pediatric oncology patients who were seen between 1982 and 2003 at the author's institution was queried to identify patients aged Saccharomyces cerevisiae 2 [PMS2] expression) and a Wilms tumor (high MSI; no MLH1 or PMS2 expression). Apart from >6 cafe-au-lait spots, he had no other signs of NF1. The patient had CZ identified for a pathogenic MLH1 mutation (593delAG frameshift) and an unclassified MLH1 variant (Met35Asn). There was strong evidence that this unclassified variant was a pathogenic mutation. The second patient was diagnosed with a non-Hodgkin lymphoma (no tissue available) and an anaplastic oligodendroglioma (low MSI; no MSH6 expression) at age 4 years and 6 years, respectively. His brother had died of a medulloblastoma at age 6 years (low MSI, no MSH6 expression). Both boys had cafe-au-lait spots. Further genetic testing was not possible. Carriage of biallelic MMR gene defects can be associated with multiple malignancies in childhood that may differ from the standard spectrum of HNPCC tumor types. In 15 pediatric patients with multiple malignancies, the authors identified 1 clear case and 1 possible case of biallelic MMR gene defect. Recognition of the inherited nature of the tumors in these patients is important for counseling these patients and their families. (c) 2007 American Cancer Society.

  2. Genetic variations in the homologous recombination repair pathway genes modify risk of glioma.

    Science.gov (United States)

    Zhang, Haishi; Liu, Yanhong; Zhou, Keke; Zhou, Chengcheng; Zhou, Renke; Cheng, Chunxia; Wei, Qingyi; Lu, Daru; Zhou, Liangfu

    2016-01-01

    Accumulative epidemiological evidence suggests that single nucleotide polymorphisms (SNPs) in genes involved in homologous recombination (HR) DNA repair pathway play an important role in glioma susceptibility. However, the effects of such SNPs on glioma risk remain unclear. We used a used a candidate pathway-based approach to elucidate the relationship between glioma risk and 12 putative functional SNPs in genes involved in the HR pathway. Genotyping was conducted on 771 histologically-confirmed glioma patients and 752 cancer-free controls from the Chinese Han population. Odds ratios (OR) were calculated both for each SNP individually and for grouped analyses, examining the effects of the numbers of adverse alleles on glioma risk, and evaluated their potential gene-gene interactions using the multifactor dimensionality reduction (MDR). In the single-locus analysis, two variants, the NBS1 rs1805794 (OR 1.42, 95% CI 1.15-1.76, P = 0.001), and RAD54L rs1048771 (OR 1.61, 95% CI 1.17-2.22, P = 0.002) were significantly associated with glioma risk. When we examined the joint effects of the risk-conferring alleles of these three SNPs, we found a significant trend indicating that the risk increases as the number of adverse alleles increase (P = 0.005). Moreover, the MDR analysis suggested a significant three-locus interaction model involving NBS1 rs1805794, MRE11 rs10831234, and ATM rs227062. These results suggested that these variants of the genes involved in the HR pathway may contribute to glioma susceptibility.

  3. Polymorphisms in DNA Repair Gene and Susceptibility to Glioma: A Systematic Review and Meta-Analysis Based on 33 Studies with 15 SNPs in 9 Genes.

    Science.gov (United States)

    Liu, Kun; Jiang, Yugang

    2017-03-01

    At present, many publications have evaluated the correlation between the DNA repair gene polymorphisms and glioma susceptibility. However, the results remain inconclusive. The aim of this research is to exhaustively assess the association of genetic polymorphisms in DNA repair genes with glioma risk in human. Meta-analysis method was conducted, and 33 studies with 15 SNPs in 9 genes were included (12553 glioma cases and 17178 controls). Correlation strength was evaluated by odds ratio with a 95 % confidence interval. Rs1799782 T allele and rs25487A allele might bring about higher risk of glioma in Asian population. Rs1805377 G allele was an increased risk genetic factor of glioma. Asian carried with rs3212986 A allele was more likely to have glioma. Rs1800067 G allele was a risk factor of developing glioma. Carriers with rs12917 CC genotype in MGMT gene had higher risk of glioma in Caucasian than other non-CC genotype carriers. Carriers with rs1136410 T allele in PARP1 gene could more likely to develop glioma in Caucasian. This meta-analysis suggests that glioma susceptibility is associated with rs1799782 and rs25487 of X-ray repair complementing defective repair in Chinese hamster cells 1 (XRCC1), rs1805377 of XRCC4, rs1800067 of excision repair cross-complementing rodent repair deficiency complementation group 4 (ERCC4) and rs3212986 of ERCC1 in Asian population, and rs12917 of O-6-methylguanine-DNA methyltransferase (MGMT) and rs1136410 of poly(ADP-ribose) polymerase 1 (PARP1) in Caucasian population.

  4. Cloning, comparative mapping, and RNA expression of the mouse homologues of the Saccharomyces cerevisiae nucleotide excision repair gene RAD23.

    NARCIS (Netherlands)

    P.J. van der Spek (Peter); C.E. Visser (Cécile); F. Hanaoka (Fumio); B. Smit (Bep); A. Hagemeijer (Anne); D. Bootsma (Dirk); J.H.J. Hoeijmakers (Jan)

    1996-01-01

    textabstractThe Saccharomyces cerevisiae RAD23 gene is involved in nucleotide excision repair (NER). Two human homologs of RAD23, HHR23A and HHR23B (HGMW-approved symbols RAD23A and RAD23B), were previously isolated. The HHR23B protein is complexed with the protein defective in the cancer-prone

  5. Sequence conservation of the rad21 Schizosaccharomyces pombe DNA double-strand break repair gene in human and mouse.

    NARCIS (Netherlands)

    M.J. McKay (Michael); C. Troelstra (Christine); P.J. van der Spek (Peter); R. Kanaar (Roland); B. Smit (Bep); A. Hagemeijer (Anne); D. Bootsma (Dirk); J.H.J. Hoeijmakers (Jan)

    1996-01-01

    textabstractThe rad21 gene of Schizosaccharomyces pombe is involved in the repair of ionizing radiation-induced DNA double-strand breaks. The isolation of mouse and human putative homologs of rad21 is reported here. Alignment of the predicted amino acid sequence of Rad21 with the mammalian proteins

  6. Polymorphisms in nucleotide excision repair genes, smoking and intake of fruit and vegetables in relation to lung cancer

    DEFF Research Database (Denmark)

    Raaschou-Nielsen, Ole; Sørensen, Mette; Overvad, Kim

    2007-01-01

    in the XPC, XPA and XPD genes involved in the nucleotide excision DNA repair pathway and analysed possible interactions with smoking and dietary intake of fruit and vegetables in relation to risk for lung cancer. We found that intake of fruit was associated with lower risk for lung cancer only among carriers...

  7. Modulation of radiation-induced base excision repair pathway gene expression by melatonin

    Directory of Open Access Journals (Sweden)

    Saeed Rezapoor

    2017-01-01

    Full Text Available Objective: Approximately 70% of all cancer patients receive radiotherapy. Although radiotherapy is effective in killing cancer cells, it has adverse effects on normal cells as well. Melatonin (MLT as a potent antioxidant and anti-inflammatory agent has been proposed to stimulate DNA repair capacity. We investigated the capability of MLT in the modification of radiation-induced DNA damage in rat peripheral blood cells. Materials and Methods: In this experimental study, male rats (n = 162 were divided into 27 groups (n = 6 in each group including: irradiation only, vehicle only, vehicle with irradiation, 100 mg/kg MLT alone, 100 mg/kg MLT plus irradiation in 3 different time points, and control. Subsequently, they were irradiated with a single whole-body X-ray radiation dose of 2 and 8 Gy at a dose rate of 200 MU/min. Rats were given an intraperitoneal injection of MLT or the same volume of vehicle alone 1 h prior to irradiation. Blood samples were also taken 8, 24, and 48 h postirradiation, in order to measure the 8-oxoguanine glycosylase1 (Ogg1, Apex1, and Xrcc1 expression using quantitative real-time-polymerase chain reaction. Results: Exposing to the ionizing radiation resulted in downregulation of Ogg1, Apex1, and Xrcc1 gene expression. The most obvious suppression was observed in 8 h after exposure. Pretreatments with MLT were able to upregulate these genes when compared to the irradiation-only and vehicle plus irradiation groups (P < 0.05 in all time points. Conclusion: Our results suggested that MLT in mentioned dose may result in modulation of Ogg1, Apex1, and Xrcc1 gene expression in peripheral blood cells to reduce X-ray irradiation-induced DNA damage. Therefore, administration of MLT may increase the normal tissue tolerance to radiation through enhancing the cell DNA repair capacity. We believed that MLT could play a radiation toxicity reduction role in patients who have undergone radiation treatment as a part of cancer radiotherapy.

  8. Risk of colorectal cancer for people with a mutation in both a MUTYH and a DNA mismatch repair gene

    Science.gov (United States)

    Win, Aung Ko; Reece, Jeanette C.; Buchanan, Daniel D.; Clendenning, Mark; Young, Joanne P.; Cleary, Sean P.; Kim, Hyeja; Cotterchio, Michelle; Dowty, James G.; MacInnis, Robert J.; Tucker, Katherine M.; Winship, Ingrid M.; Macrae, Finlay A.; Burnett, Terrilea; Le Marchand, Loïc; Casey, Graham; Haile, Robert W.; Newcomb, Polly A.; Thibodeau, Stephen N.; Lindor, Noralane M.; Hopper, John L.; Gallinger, Steven; Jenkins, Mark A.

    2015-01-01

    The base excision repair protein, MUTYH, functionally interacts with the DNA mismatch repair (MMR) system. As genetic testing moves from testing one gene at a time, to gene panel and whole exome next generation sequencing approaches, understanding the risk associated with co-existence of germline mutations in these genes will be important for clinical interpretation and management. From the Colon Cancer Family Registry, we identified 10 carriers who had both a MUTYH mutation (6 with c.1187G>A p.(Gly396Asp), 3 with c.821G>A p.(Arg274Gln), and 1 with c.536A>G p.(Tyr179Cys)) and a MMR gene mutation (3 in MLH1, 6 in MSH2, and 1 in PMS2), 375 carriers of a single (monoallelic) MUTYH mutation alone, and 469 carriers of a MMR gene mutation alone. Of the 10 carriers of both gene mutations, 8 were diagnosed with colorectal cancer. Using a weighted cohort analysis, we estimated that risk of colorectal cancer for carriers of both a MUTYH and a MMR gene mutation was substantially higher than that for carriers of a MUTYH mutation alone [hazard ratio (HR) 21.5, 95 % confidence interval (CI) 9.19–50.1; p colorectal cancer for carriers of a MMR gene mutation alone. Our finding suggests MUTYH mutation testing in MMR gene mutation carriers is not clinically informative. PMID:26202870

  9. Spectrum of mismatch repair gene mutations and clinical presentation of Hispanic individuals with Lynch syndrome.

    Science.gov (United States)

    Sunga, Annette Y; Ricker, Charité; Espenschied, Carin R; Castillo, Danielle; Melas, Marilena; Herzog, Josef; Bannon, Sarah; Cruz-Correa, Marcia; Lynch, Patrick; Solomon, Ilana; Gruber, Stephen B; Weitzel, Jeffrey N

    2017-04-01

    Lynch syndrome (LS), the most common hereditary colorectal cancer syndrome, is caused by mismatch repair (MMR) gene mutations. However, data about MMR mutations in Hispanics are limited. This study aims to describe the spectrum of MMR mutations in Hispanics with LS and explore ancestral origins. This case series involved an IRB-approved retrospective chart review of self-identified Hispanic patients (n = 397) seen for genetic cancer risk assessment at four collaborating academic institutions in California, Texas, and Puerto Rico who were evaluated by MMR genotyping and/or tumor analysis. A literature review was conducted for all mutations identified. Of those who underwent clinical genetic testing (n = 176), 71 had MMR gene mutations. Nine mutations were observed more than once. One third (3/9) of recurrent mutations and two additional mutations (seen only once) were previously reported in Spain, confirming the influence of Spanish ancestry on MMR mutations in Hispanic populations. The recurrent mutations identified (n = 9) included both previously reported mutations as well as unique mutations not in the literature. This is the largest report of Hispanic MMR mutations in North America; however, a larger sample and haplotype analyses are needed to better understand recurrent MMR mutations in Hispanic populations. Copyright © 2017. Published by Elsevier Inc.

  10. Arsenic Trioxide Promotes Paclitaxel Cytotoxicity in Resistant Breast Cancer Cells.

    Science.gov (United States)

    Bakhshaiesh, Tayebeh Oghabi; Armat, Marzie; Shanehbandi, Dariush; Sharifi, Simin; Baradaran, Behzad; Hejazi, Mohammad Saeed; Samadi, Nasser

    2015-01-01

    A partial response or resistance to chemotherapeutic agents is considered as a main obstacle in treatment of patients with cancer, including breast cancer. Refining taxane-based treatment procedures using adjuvant or combination treatment is a novel strategy to increase the efficiency of chemotherapy. PPM1D is a molecule activated by reactive oxygen species. whose expression is reported to modulate the recruitment of DNA repair molecules. In this study we examined the impact of arsenic trioxide on efficacy of paclitaxel-induced apoptosis in paclitaxel-resistant MCF-7 cells. We also investigated the expression of PPM1D and TP53 genes in response to this combination treatment. Resistant cells were developed from the parent MCF-7 cell line by applying increasing concentrations of paclitaxel. MTT assays were applied to determine the rate of cell survival. DAPI staining using fluorescent microscopy was employed to study apoptotic bodies. Real-time RT-PCR analysis was also applied to determine PPM1D mRNA levels. Our results revealed that combination of arsenic trioxide and paclitaxel elevates the efficacy of the latter in induction of apoptosis in MCF-7/PAC resistant cells. Applying arsenic trioxide also caused significant decreases in PPM1D mRNA levels (parsenic trioxide increases paclitaxel-induced apoptosis by down regulation of PPM1D expression. PPM1D dependent signaling can be considered as a novel target to improve the efficacy of chemotherapeutic agents in resistant breast cancer cells.

  11. Assessment of single nucleotide polymorphisms in screening 52 DNA repair and cell cycle control genes in Fanconi anemia patients

    Directory of Open Access Journals (Sweden)

    Petrović Sandra

    2015-01-01

    Full Text Available Fanconi anemia (FA is a rare genetically heterogeneous disorder associated with bone marrow failure, birth defects and cancer susceptibility. Apart from the disease- causing mutations in FANC genes, the identification of specific DNA variations, such as single nucleotide polymorphisms (SNPs, in other candidate genes may lead to a better clinical description of this condition enabling individualized treatment with improvement of the prognosis. In this study, we have assessed 95 SNPs located in 52 key genes involved in base excision repair (BER, nucleotide excision repair (NER, mismatch repair (MMR, double strand break (DSB repair and cell cycle control using a DNA repair chip (Asper Biotech, Estonia which includes most of the common variants for the candidate genes. The SNP genotyping was performed in five FA-D2 patients and in one FA-A patient. The polymorphisms studied were synonymous (n=10, nonsynonymous (missense (n=52 and in non-coding regions of the genome (introns and 5 ‘and 3’ untranslated regions (UTR (n=33. Polymorphisms found at the homozygous state are selected for further analysis. Our results have shown a significant inter-individual variability among patients in the type and the frequency of SNPs and also elucidate the need for further studies of polymorphisms located in ATM, APEX APE 1, XRCC1, ERCC2, MSH3, PARP4, NBS1, BARD1, CDKN1B, TP53 and TP53BP1 which may be of great importance for better clinical description of FA. In addition, the present report recommends the use of SNPs as predictive and prognostic genetic markers to individualize therapy of FA patients. [Projekat Ministarstva nauke Republike Srbije, br. 173046

  12. Nucleotide fluctuation of RecA repair gene in Siberian permafrost Psychrobacter cryohalolentis K5

    Science.gov (United States)

    Tremberger, George, Jr.; Holden, T.; Cheung, E.; Subramaniam, R.; Sullivan, R.; Schneider, P.; Flamholz, A.; Marchese, P.; Lieberman, D.; Cheung, T.

    2008-08-01

    A nucleotide sequence can be expressed as a numerical sequence when each nucleotide is assigned its proton number. A resulting gene numerical sequence can be investigated for its fractal dimension in terms of evolution and chemical properties for comparative studies. We have investigated such nucleotide fluctuation in the RecA repair gene of Psychrobacter cryohalolentis K5, Psychrobacter arcticus 273-4, and Psychrobacter sp. PRwf-1. The fractal dimension was found to correlate with the gene's operating temperature with the highest fractal dimension associated with P. cryohalolentis K5 living at the low temperatures found in Siberian permafrost. The CpG dinucleotide content was found to be about 5% for the three species of Psychrobacters, which is substantially lower than that of Deinococcus radiodurans at about 12%. The average nucleotide pair-wise free energy was found to be lowest for Psychrobacter sp. PRwf-1, the species with the lowest fractal dimension of the three, consistent with the recent finding that Psychrobacter sp. PRw-f1 has a temperature growth maximum of 15-20°C higher than P. arcticus 273-4 and P. cryohaloentis K5. The results suggest that microbial vitality in extreme environments is associated with fractal dimension as well as high CpG dinucleotide content, while the average nucleotide pair-wise free energy is related to the operating environment. Evidence that extreme temperature operation would impose constraints measurable by Shannon entropy is also discussed. A quantitative estimate of an entropy-based measure having the characteristics of a mechanical pressure shows that the Psychrobacter RecA sequence experiences lower pressure than that of the human HAR1 sequence.

  13. DNA Base-Excision Repair Genes OGG1 and NTH1 in Brazilian Lung Cancer Patients.

    Science.gov (United States)

    Couto, Patricia G; Bastos-Rodrigues, Luciana; Carneiro, Juliana G; Guieiro, Fernanda; Bicalho, Maria Aparecida; Leidenz, Franciele B; Bicalho, Ana J; Friedman, Eitan; De Marco, Luiz

    2015-12-01

    Lung cancer is the leading global cause of cancer-related mortality and is associated with poor prognosis. To improve survival rates of lung cancer patients, better understanding of tumorigenic mechanisms is necessary, which may lead to development of new therapeutic strategies. The hOGG1 and NTH1 genes act in the DNA BER repair pathway and their involvement in lung cancer pathogenesis has been analyzed in several populations. We analyzed targeted regions of the hOGG1 and NTH1 genes in 96 Brazilian patients with non-small-cell lung cancer (NSCLC) and 89 cancer-free, ethnically matched controls. The NTH1 c.98G>T polymorphism rs2302172 (p = 0.02 and p = 0.02 for allele and genotype frequency between cases and controls, respectively) and the 140-17C> T variant (rs2233518) (p = 0.02 and p = 0.02 for allele and genotype frequency between cases and controls, respectively) were detected in four lung cancer cases (4 %) while the NTH1 Q131K (C391A) polymorphism was found in seven lung cancer cases (7 %) (p = 0.001 and p = 0.008, for allele and genotype frequency between cases and controls, respectively). None of these sequence variants were detected in controls. The Ser326Cys (C1245G, rs1052133) polymorphism in the OGG1 gene was detected in 42 % of analyzed NSCLC patients and in 34 % of the controls (p = 0.11 and p = 0.25 for allele and genotype frequency between cases and controls, respectively). Our study provides preliminary evidence that polymorphisms in OGG1 do not contribute to development of NSCLC in Brazilian patients and that NTH1 polymorphisms may be associated with NSCLC pathogenesis.

  14. Preferential repair of ionizing radiation-induced damage in the transcribed strand of an active human gene is defective in Cockayne syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Leadon, S.A. (Univ. of North Carolina, Chapel Hill, NC (United States)); Copper, P.K. (Lawrence Berkeley Lab., CA (United States))

    1993-11-15

    Cells from patients with Cockayne syndrome (CS), which are sensitive to killing by UV although overall damage removal appears normal, are specifically defective in repair of UV damage in actively transcribe genes. Because several CS strains display cross-sensitivity to killing by ionizing radiation, the authors examined whether ionizing radiation-induced damage in active genes is preferentially repaired by normal cells and whether the radiosensitivity of CS cells can be explained by a defect in this process. They found that ionizing radiation-induced damage was repaired more rapidly in the transcriptionally active metallothionein IIA (MTIIA) gene than in the inactive MTIIB gene or in the genome overall in normal cells as a result of faster repair on the transcribed strand of MTIIA. Cells of the radiosensitive CS strain CS1AN are completely defective in this strand-selective repair of ionizing radiation-induced damage, although their overall repair rate appears normal. CS3BE cells, which are intermediate in radiosensitivity, do exhibit more rapid repair of the transcribed strand but at a reduced rate compared to normal cells. Xeroderma pigmentosum complementation group A cells, which are hypersensitive to UV light because of a defect in the nucleotide excision repair pathway but do not show increased sensitivity to ionizing radiation, preferentially repair ionizing radiation-induced damage on the transcribed strand of MTIIA. Thus, the ability to rapidly repair ionizing radiation-induced damage in actively transcribing genes correlates with cell survival. The results extend the generality of preferential repair in active genes to include damage other than bulky lesions.

  15. Preferential repair of ionizing radiation-induced damage in the transcribed strand of an active human gene is defective in Cockayne syndrome.

    Science.gov (United States)

    Leadon, S A; Cooper, P K

    1993-11-15

    Cells from patients with Cockayne syndrome (CS), which are sensitive to killing by UV although overall damage removal appears normal, are specifically defective in repair of UV damage in actively transcribed genes. Because several CS strains display cross-sensitivity to killing by ionizing radiation, we examined whether ionizing radiation-induced damage in active genes is preferentially repaired by normal cells and whether the radiosensitivity of CS cells can be explained by a defect in this process. We found that ionizing radiation-induced damage was repaired more rapidly in the transcriptionally active metallothionein IIA (MTIIA) gene than in the inactive MTIIB gene or in the genome overall in normal cells as a result of faster repair on the transcribed strand of MTIIA. Cells of the radiosensitive CS strain CS1AN are completely defective in this strand-selective repair of ionizing radiation-induced damage, although their overall repair rate appears normal. CS3BE cells, which are intermediate in radiosensitivity, do exhibit more rapid repair of the transcribed strand but at a reduced rate compared to normal cells. Xeroderma pigmentosum complementation group A cells, which are hypersensitive to UV light because of a defect in the nucleotide excision repair pathway but do not show increased sensitivity to ionizing radiation, preferentially repair ionizing radiation-induced damage on the transcribed strand of MTIIA. Thus, the ability to rapidly repair ionizing radiation-induced damage in actively transcribing genes correlates with cell survival. Our results extend the generality of preferential repair in active genes to include damage other than bulky lesions.

  16. Renin–angiotensin–aldosterone system related gene polymorphisms and urinary total arsenic is related to chronic kidney disease

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Jen [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Huang, Ya-Li [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Shiue, Horng-Sheng [Department of Chinese Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan (China); Chen, Tzen-Wen [Division of Nephrology, Department of Internal Medicine, Taipei Medical University Hospital, Taipei, Taiwan (China); Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Lin, Yuh-Feng [Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, New Taipei, Taiwan (China); Huang, Chao-Yuan [Department of Urology, National Taiwan University Hospital, College of Medicine National Taiwan University, Taipei, Taiwan (China); Lin, Ying-Chin [Department of Family Medicine, Shung Ho Hospital, Taipei Medical University, New Taipei, Taiwan (China); Department of Health Examination, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan (China); Division of Family Medicine, School of Medicine, Taipei Medical University, Taipei, Taiwan (China); Han, Bor-Cheng [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Hsueh, Yu-Mei, E-mail: ymhsueh@tmu.edu.tw [School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China); Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China)

    2014-09-01

    A recent study demonstrated that an increased risk of chronic kidney disease (CKD) was associated with high urinary total arsenic levels. However, whether genomic instability is related to CKD remains unclear. An association between CKD and genetic polymorphisms of regulation enzymes of the renin–angiotensin–aldosterone system (RAAS), such as angiotensin-converting enzyme (ACE), angiotensinogen (AGT), angiotensin II type I receptor (AT1R), and aldosterone synthase (CYP11B2) has not been shown. The aim of the present study was to investigate the relationship between arsenic, genetic polymorphisms of RAAS enzymes and CKD. A total of 233 patients and 449 age- and gender-matched controls were recruited from the Taipei Medical University Hospital, Taipei Municipal Wan Fang Hospital and the Shin Kong Wu Ho-Su Memorial Hospital. Concentrations of urinary arsenic were determined by a high-performance liquid chromatography-linked hydride generator, and atomic absorption spectrometry. Polymorphisms of ACE(I/D), AGT(A[− 20]C), (T174M), (M235T), AT1R(A1166C) and CYP11B2(C[− 344]T) were examined by polymerase chain reaction and restriction fragment length polymorphism. Subjects carrying the CYP11B2 TT genotype had a higher odds ratio (OR), 1.39 (0.96–2.01), of CKD; while those with the AGT(A[− 20]C) CC genotype had an inverse OR of CKD (0.20 (0.05–0.81)), and a high-risk genotype was defined as A/A + A/C for AGT(A[− 20C]) and T/T for CYP11B2(C[− 344]T). The trend test showed a higher OR for CKD in patients who had either high urinary total arsenic levels or carried the high-risk genotype, or both, compared to patients with low urinary total arsenic levels, who carried the low-risk genotype, and could also be affected by the hypertension or diabetes status. - Highlights: • AGT(− 20 C) and CYP11B2(− 344 T) genotypes were significantly associated with CKD. • Combined effect of high-risk genotypes and high urinary total arsenic on OR of CKD. • Combined

  17. Association of common variants in mismatch repair genes and breast cancer susceptibility: a multigene study

    Directory of Open Access Journals (Sweden)

    Pina Julieta

    2009-09-01

    Full Text Available Abstract Background MMR is responsible for the repair of base-base mismatches and insertion/deletion loops. Besides this, MMR is also associated with an anti-recombination function, suppressing homologous recombination. Losses of heterozygosity and/or microsatellite instability have been detected in a large number of skin samples from breast cancer patients, suggesting a potential role of MMR in breast cancer susceptibility. Methods We carried out a hospital-based case-control study in a Caucasian Portuguese population (287 cases and 547 controls to estimate the susceptibility to non-familial breast cancer associated with some polymorphisms in mismatch repair genes (MSH3, MSH4, MSH6, MLH1, MLH3, PMS1 and MUTYH. Results Using unconditional logistic regression we found that MLH3 (L844P, G>A polymorphism GA (Leu/Pro and AA (Pro/Pro genotypes were associated with a decreased risk: OR = 0.65 (0.45-0.95 (p = 0.03 and OR = 0.62 (0.41-0.94 (p = 0.03, respectively. Analysis of two-way SNP interaction effects on breast cancer revealed two potential associations to breast cancer susceptibility: MSH3 Ala1045Thr/MSH6 Gly39Glu - AA/TC [OR = 0.43 (0.21-0.83, p = 0.01] associated with a decreased risk; and MSH4 Ala97Thr/MLH3 Leu844Pro - AG/AA [OR = 2.35 (1.23-4.49, p = 0.01], GG/AA [OR = 2.11 (1.12-3,98, p = 0.02], and GG/AG [adjusted OR = 1.88 (1.12-3.15, p = 0.02] all associated with an increased risk for breast cancer. Conclusion It is possible that some of these common variants in MMR genes contribute significantly to breast cancer susceptibility. However, further studies with a large sample size will be needed to support our results.

  18. Combined effects of scaffold stiffening and mechanical preconditioning cycles on construct biomechanics, gene expression, and tendon repair biomechanics.

    Science.gov (United States)

    Nirmalanandhan, Victor Sanjit; Juncosa-Melvin, Natalia; Shearn, Jason T; Boivin, Gregory P; Galloway, Marc T; Gooch, Cynthia; Bradica, Gino; Butler, David L

    2009-08-01

    Our group has previously reported that in vitro mechanical stimulation of tissue-engineered tendon constructs significantly increases both construct stiffness and the biomechanical properties of the repair tissue after surgery. When optimized using response surface methodology, our results indicate that a mechanical stimulus with three components (2.4% strain, 3000 cycles/day, and one cycle repetition) produced the highest in vitro linear stiffness. Such positive correlations between construct and repair stiffness after surgery suggest that enhancing structural stiffness before surgery could not only accelerate repair stiffness but also prevent premature failures in culture due to poor mechanical integrity. In this study, we examined the combined effects of scaffold crosslinking and subsequent mechanical stimulation on construct mechanics and biology. Autologous tissue-engineered constructs were created by seeding mesenchymal stem cells (MSCs) from 15 New Zealand white rabbits on type I collagen sponges that had undergone additional dehydrothermal crosslinking (termed ADHT in this manuscript). Both constructs from each rabbit were mechanically stimulated for 8h/day for 12 consecutive days with half receiving 100 cycles/day and the other half receiving 3000 cycles/day. These paired MSC-collagen autologous constructs were then implanted in bilateral full-thickness, full-length defects in the central third of rabbit patellar tendons. Increasing the number of in vitro cycles/day delivered to the ADHT constructs in culture produced no differences in stiffness or gene expression and no changes in biomechanical properties or histology 12 weeks after surgery. Compared to MSC-based repairs from a previous study that received no additional treatment in culture, ADHT crosslinking of the scaffolds actually lowered the 12-week repair stiffness. Thus, while ADHT crosslinking may initially stiffen a construct in culture, this specific treatment also appears to mask any benefits

  19. Impact of life stage and duration of exposure on arsenic-induced proliferative lesions, neoplasia, and gene expression in male C3H mice.

    Science.gov (United States)

    Previous studies have demonstrated increased liver and adrenal tumor incidence in male mice exposed gestationally to 85 ppm inorganic arsenic via the dams’ drinking water. To further characterize age susceptibility to arsenic carcinogenesis we have administered 85 ppm sodium ars...

  20. Use of the comet-FISH assay to compare DNA damage and repair in p53 and hTERT genes following ionizing radiation.

    Directory of Open Access Journals (Sweden)

    Declan J McKenna

    Full Text Available The alkaline single cell gel electrophoresis (comet assay can be combined with fluorescent in situ hybridisation (FISH methodology in order to investigate the localisation of specific gene domains within an individual cell. The number and position of the fluorescent signal(s provides information about the relative damage and subsequent repair that is occurring in the targeted gene domain(s. In this study, we have optimised the comet-FISH assay to detect and compare DNA damage and repair in the p53 and hTERT gene regions of bladder cancer cell-lines RT4 and RT112, normal fibroblasts and Cockayne Syndrome (CS fibroblasts following γ-radiation. Cells were exposed to 5Gy γ-radiation and repair followed for up to 60 minutes. At each repair time-point, the number and location of p53 and hTERT hybridisation spots was recorded in addition to standard comet measurements. In bladder cancer cell-lines and normal fibroblasts, the p53 gene region was found to be rapidly repaired relative to the hTERT gene region and the overall genome, a phenomenon that appeared to be independent of hTERT transcriptional activity. However, in the CS fibroblasts, which are defective in transcription coupled repair (TCR, this rapid repair of the p53 gene region was not observed when compared to both the hTERT gene region and the overall genome, proving the assay can detect variations in DNA repair in the same gene. In conclusion, we propose that the comet-FISH assay is a sensitive and rapid method for detecting differences in DNA damage and repair between different gene regions in individual cells in response to radiation. We suggest this increases its potential for measuring radiosensitivity in cells and may therefore have value in a clinical setting.

  1. Use of the Comet-FISH Assay to Compare DNA Damage and Repair in p53 and hTERT Genes following Ionizing Radiation

    Science.gov (United States)

    McKenna, Declan J.; Doherty, Bernadette A.; Downes, C. Stephen; McKeown, Stephanie R.; McKelvey-Martin, Valerie J.

    2012-01-01

    The alkaline single cell gel electrophoresis (comet) assay can be combined with fluorescent in situ hybridisation (FISH) methodology in order to investigate the localisation of specific gene domains within an individual cell. The number and position of the fluorescent signal(s) provides information about the relative damage and subsequent repair that is occurring in the targeted gene domain(s). In this study, we have optimised the comet-FISH assay to detect and compare DNA damage and repair in the p53 and hTERT gene regions of bladder cancer cell-lines RT4 and RT112, normal fibroblasts and Cockayne Syndrome (CS) fibroblasts following γ-radiation. Cells were exposed to 5Gy γ-radiation and repair followed for up to 60 minutes. At each repair time-point, the number and location of p53 and hTERT hybridisation spots was recorded in addition to standard comet measurements. In bladder cancer cell-lines and normal fibroblasts, the p53 gene region was found to be rapidly repaired relative to the hTERT gene region and the overall genome, a phenomenon that appeared to be independent of hTERT transcriptional activity. However, in the CS fibroblasts, which are defective in transcription coupled repair (TCR), this rapid repair of the p53 gene region was not observed when compared to both the hTERT gene region and the overall genome, proving the assay can detect variations in DNA repair in the same gene. In conclusion, we propose that the comet-FISH assay is a sensitive and rapid method for detecting differences in DNA damage and repair between different gene regions in individual cells in response to radiation. We suggest this increases its potential for measuring radiosensitivity in cells and may therefore have value in a clinical setting. PMID:23145163

  2. Arsenic in Food

    Science.gov (United States)

    ... Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products Food Home Food Foodborne Illness & Contaminants Metals Arsenic Share ... of the Method used to Measure Arsenic in Foods Inductively Coupled Plasma-Mass Spectrometric Determination of Arsenic, ...

  3. Exome sequencing identifies rare deleterious mutations in DNA repair genes FANCC and BLM as potential breast cancer susceptibility alleles.

    Directory of Open Access Journals (Sweden)

    Ella R Thompson

    2012-09-01

    Full Text Available Despite intensive efforts using linkage and candidate gene approaches, the genetic etiology for the majority of families with a multi-generational breast cancer predisposition is unknown. In this study, we used whole-exome sequencing of thirty-three individuals from 15 breast cancer families to identify potential predisposing genes. Our analysis identified families with heterozygous, deleterious mutations in the DNA repair genes FANCC and BLM, which are responsible for the autosomal recessive disorders Fanconi Anemia and Bloom syndrome. In total, screening of all exons in these genes in 438 breast cancer families identified three with truncating mutations in FANCC and two with truncating mutations in BLM. Additional screening of FANCC mutation hotspot exons identified one pathogenic mutation among an additional 957 breast cancer families. Importantly, none of the deleterious mutations were identified among 464 healthy controls and are not reported in the 1,000 Genomes data. Given the rarity of Fanconi Anemia and Bloom syndrome disorders among Caucasian populations, the finding of multiple deleterious mutations in these critical DNA repair genes among high-risk breast cancer families is intriguing and suggestive of a predisposing role. Our data demonstrate the utility of intra-family exome-sequencing approaches to uncover cancer predisposition genes, but highlight the major challenge of definitively validating candidates where the incidence of sporadic disease is high, germline mutations are not fully penetrant, and individual predisposition genes may only account for a tiny proportion of breast cancer families.

  4. Contribution of DNA double-strand break repair gene XRCC3 genotypes to oral cancer susceptibility in Taiwan.

    Science.gov (United States)

    Tsai, Chia-Wen; Chang, Wen-Shin; Liu, Juhn-Cherng; Tsai, Ming-Hsui; Lin, Cheng-Chieh; Bau, Da-Tian

    2014-06-01

    The DNA repair gene X-ray repair cross complementing protein 3 (XRCC3) is thought to play a major role in double-strand break repair and in maintaining genomic stability. Very possibly, defective double-strand break repair of cells can lead to carcinogenesis. Therefore, a case-control study was performed to reveal the contribution of XRCC3 genotypes to individual oral cancer susceptibility. In this hospital-based research, the association of XRCC3 rs1799794, rs45603942, rs861530, rs3212057, rs1799796, rs861539, rs28903081 genotypes with oral cancer risk in a Taiwanese population was investigated. In total, 788 patients with oral cancer and 956 age- and gender-matched healthy controls were genotyped. The results showed that there was significant differential distribution among oral cancer and controls in the genotypic (p=0.001428) and allelic (p=0.0013) frequencies of XRCC3 rs861539. As for the other polymorphisms, there was no difference between case and control groups. In gene-lifestyle interaction analysis, we have provided the first evidence showing that there is an obvious joint effect of XRCC3 rs861539 genotype with individual areca chewing habits on oral cancer risk. In conclusion, the T allele of XRCC3 rs861539, which has an interaction with areca chewing habit in oral carcinogenesis, may be an early marker for oral cancer in Taiwanese. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  5. Constitutional Mismatch Repair Deficiency in Israel: High Proportion of Founder Mutations in MMR Genes and Consanguinity.

    Science.gov (United States)

    Baris, Hagit N; Barnes-Kedar, Inbal; Toledano, Helen; Halpern, Marisa; Hershkovitz, Dov; Lossos, Alexander; Lerer, Israela; Peretz, Tamar; Kariv, Revital; Cohen, Shlomi; Half, Elizabeth E; Magal, Nurit; Drasinover, Valerie; Wimmer, Katharina; Goldberg, Yael; Bercovich, Dani; Levi, Zohar

    2016-03-01

    Heterozygous germline mutations in any of the mismatch repair (MMR) genes, MLH1, MSH2, MSH6, and PMS2, cause Lynch syndrome (LS), an autosomal dominant cancer predisposition syndrome conferring a high risk of colorectal, endometrial, and other cancers in adulthood. Offspring of couples where both spouses have LS have a 1:4 risk of inheriting biallelic MMR gene mutations. These cause constitutional MMR deficiency (CMMRD) syndrome, a severe recessively inherited cancer syndrome with a broad tumor spectrum including mainly hematological malignancies, brain tumors, and colon cancer in childhood and adolescence. Many CMMRD children also present with café au lait spots and axillary freckling mimicking neurofibromatosis type 1. We describe our experience in seven CMMRD families demonstrating the role and importance of founder mutations and consanguinity on its prevalence. Clinical presentations included brain tumors, colon cancer, lymphoma, and small bowel cancer. In children from two nonconsanguineous Ashkenazi Jewish (AJ) families, the common Ashkenazi founder mutations were detected; these were homozygous in one family and compound heterozygous in the other. In four consanguineous families of various ancestries, different homozygous mutations were identified. In a nonconsanguineous Caucasus/AJ family, lack of PMS2 was demonstrated in tumor and normal tissues; however, mutations were not identified. CMMRD is rare, but, especially in areas where founder mutations for LS and consanguinity are common, pediatricians should be aware of it since they are the first to encounter these children. Early diagnosis will enable tailored cancer surveillance in the entire family and a discussion regarding prenatal genetic diagnosis. © 2015 Wiley Periodicals, Inc.

  6. The Association of Low-Penetrance Variants in DNA Repair Genes with Colorectal Cancer: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Aggarwal, Nikhil; Donald, Neil D; Malik, Salim; Selvendran, Subothini S; McPhail, Mark Jw; Monahan, Kevin J

    2017-07-27

    Approximately 35% of colorectal cancer (CRC) risk is attributable to heritable factors known hereditary syndromes, accounting for 6%. The remainder may be due to lower penetrance polymorphisms particularly of DNA repair genes. DNA repair pathways, including base excision repair (BER), nucleotide excision repair (NER), mismatch repair (MMR), direct reversal repair (DRR), and double-strand break repair are complex, evolutionarily conserved, and critical in carcinogenesis. Germline mutations in these genes are associated with high-penetrance CRC syndromes such as Lynch syndrome. However, the association of low-penetrance polymorphisms of DNA repair genes with CRC risk remains unclear. A systematic literature review of PubMed, Embase, and HuGENet databases was conducted. Pre-specified criteria determined study inclusion/exclusion. Per-allele, pooled odds ratios disclosed the risk attributed to each variant. Heterogeneity was investigated by subgroup analyses for ethnicity and tumor location; funnel plots and Egger's test assessed publication bias. Sixty-one polymorphisms in 26 different DNA repair genes were identified. Meta-analyses for 22 polymorphisms in 17 genes revealed that six polymorphisms were significantly associated with CRC risk within BER (APE1, PARP1), NER (ERCC5, XPC), double-strand break (RAD18), and DRR (MGMT), but none within MMR. Subgroup analyses revealed significant association of OGG1 rs1052133 with rectal cancer risk. Egger's test revealed no publication bias. Low-penetrance polymorphisms in DNA repair genes alter susceptibility to CRC. Future studies should therefore analyze whole-genome polymorphisms and any synergistic effects on CRC risk.Translational impact:This knowledge may enhance CRC risk assessment and facilitate a more personalized approach to cancer prevention.

  7. Association between DNA damage response and repair genes and risk of invasive serous ovarian cancer.

    Directory of Open Access Journals (Sweden)

    Joellen M Schildkraut

    Full Text Available BACKGROUND: We analyzed the association between 53 genes related to DNA repair and p53-mediated damage response and serous ovarian cancer risk using case-control data from the North Carolina Ovarian Cancer Study (NCOCS, a population-based, case-control study. METHODS/PRINCIPAL FINDINGS: The analysis was restricted to 364 invasive serous ovarian cancer cases and 761 controls of white, non-Hispanic race. Statistical analysis was two staged: a screen using marginal Bayes factors (BFs for 484 SNPs and a modeling stage in which we calculated multivariate adjusted posterior probabilities of association for 77 SNPs that passed the screen. These probabilities were conditional on subject age at diagnosis/interview, batch, a DNA quality metric and genotypes of other SNPs and allowed for uncertainty in the genetic parameterizations of the SNPs and number of associated SNPs. Six SNPs had Bayes factors greater than 10 in favor of an association with invasive serous ovarian cancer. These included rs5762746 (median OR(odds ratio(per allele = 0.66; 95% credible interval (CI = 0.44-1.00 and rs6005835 (median OR(per allele = 0.69; 95% CI = 0.53-0.91 in CHEK2, rs2078486 (median OR(per allele = 1.65; 95% CI = 1.21-2.25 and rs12951053 (median OR(per allele = 1.65; 95% CI = 1.20-2.26 in TP53, rs411697 (median OR (rare homozygote = 0.53; 95% CI = 0.35 - 0.79 in BACH1 and rs10131 (median OR( rare homozygote = not estimable in LIG4. The six most highly associated SNPs are either predicted to be functionally significant or are in LD with such a variant. The variants in TP53 were confirmed to be associated in a large follow-up study. CONCLUSIONS/SIGNIFICANCE: Based on our findings, further follow-up of the DNA repair and response pathways in a larger dataset is warranted to confirm these results.

  8. DNA repair gene XRCC1 polymorphisms, smoking, and bladder cancer risk: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Shan Li

    Full Text Available BACKGROUND AND OBJECTIVE: The X-ray repair cross-complementing group 1 (XRCC1 protein plays a crucial role in base excision repair (BER pathway by acting as a scaffold for other BER enzymes. Variants in the XRCC1 gene might alter protein structure or function or create alternatively spliced proteins which may influence BER efficiency and hence affect individual susceptibility to bladder cancer. Recent epidemiological studies have shown inconsistent associations between these polymorphisms and bladder cancer. To clarify the situation, a comprehensive meta-analysis of all available studies was performed in this study. METHODS: PubMed, EMBASE, and Chinese Biomedical Literature database (CBM databases have been systematically searched to identify all relevant studies for the period up to February 2013. Data were abstracted independently by two reviewers and Odds ratios (ORs and 95% confidence intervals (CIs were calculated. Subgroup analyses were performed mainly by ethnicity and smoking status. RESULTS: A total of 26 case-control studies, including 24 studies for R399Q polymorphism, 15 studies for R194W polymorphism, and 7 studies for R280H polymorphism met the inclusion criteria and were selected. With respect to R399Q polymorphism, significantly decreased bladder cancer risk was found among smokers (AA vs. GG: OR=0.693, 95%CI= 0.515-0.932, P=0.015 and recessive model AA vs. GA+GG: OR=0.680, 95%CI= 0.515-0.898, P=0.007, respectively. With respect to R194W and R280H polymorphism, significantly increased bladder cancer risk were observed among Asians (TT+CT vs. CC:OR = 1.327, 95% CI 1.086-1.622, P=0.006 for R194W, and AA+GA vs. GG: OR=2.094, 95% CI 1.211-3.621, P=0.008 for R280H, respectively. CONCLUSIONS: This meta-analysis suggests that the XRCC1 R399Q polymorphism may play a protective role against bladder cancer among smokers. However, the XRCC1 R194W and R280H polymorphisms were both associated with increased bladder cancer risk among Asians

  9. Clinical heterogeneity within xeroderma pigmentosum associated with mutations in the DNA repair and transcription gene ERCC3

    Energy Technology Data Exchange (ETDEWEB)

    Vermeulen, W.; Kleijer, W.J.; Bootsma, D.; Hoeijmakers, J.H.J.; Weeda, G. (Erasmus Univ., Rotterdam (Netherlands)); Scott, R.J.; Rodgers, S.; Mueller, H.J. (Univ. Hospital, Basel (Switzerland)); Cole, J.; Arlett, C.F. (Univ. of Sussex, Brighton (United Kingdom))

    1994-02-01

    The human DNA excision repair gene ERCC3 specifically corrects the nucleotide excision repair (NER) defect of xeroderma pigmentosum (XP) complementation group B. In addition to its function in NER, the ERCC3 DNA helicase was recently identified as one of the components of the human BTF2/TFIIH transcription factor complex, which is required for initiation of transcription of class II genes. To date, a single patient (XP11BE) has been assigned to this XP group B (XP-B), with the remarkable conjunction of two autosomal recessive DNA repair deficiency disorders: XP and Cockayne syndrome (CS). The intriguing involvement of the ERCC3 protein in the vital process of transcription may provide an explanation for the rarity, severity, and wide spectrum of clinical features in this complementation group. Here the authors report the identification of two new XP-B patients: XPCS1BA and XPCS2BA (siblings), by microneedle injection of the cloned ERCC3 repair gene as well as by cell hybridization. Molecular analysis of the ERCC3 gene in both patients revealed a single base substitution causing a missense mutation in a region that is completely conserved in yeast, Drosophila, mouse, and human ERCC3. As in patient XP11BE, the expression of only one allele (paternal) is detected. The mutation causes a virtually complete inactivation of the NER function of the protein. Despite this severe NER defect, both patients display a late onset of neurologic impairment, mild cutaneous symptoms, and a striking absence of skin tumors even at an age of >40 years. Analysis of the frequency of hprt[sup [minus

  10. Arsenic exposure and intestinal microbiota in children from Sirajdikhan, Bangladesh.

    Science.gov (United States)

    Dong, Xiaoxi; Shulzhenko, Natalia; Lemaitre, Julien; Greer, Renee L; Peremyslova, Kate; Quamruzzaman, Quazi; Rahman, Mahmudar; Hasan, Omar Sharif Ibn; Joya, Sakila Afroz; Golam, Mostofa; Christiani, David C; Morgun, Andriy; Kile, Molly L

    2017-01-01

    Arsenic has antimicrobial properties at high doses yet few studies have examined its effect on gut microbiota. This warrants investigation since arsenic exposure increases the risk of many diseases in which gut microbiota have been shown to play a role. We examined the association between arsenic exposure from drinking water and the composition of intestinal microbiota in children exposed to low and high arsenic levels during prenatal development and early life. 16S rRNA gene sequencing revealed that children with high arsenic exposure had a higher abundance of Proteobacteria in their stool compared to matched controls with low arsenic exposure. Furthermore, whole metagenome shotgun sequencing identified 332 bacterial SEED functions that were enriched in the high exposure group. A separate model showed that these genes, which included genes involved in virulence and multidrug resistance, were positively correlated with arsenic concentration within the group of children in the high arsenic group. We performed reference free genome assembly, and identified strains of E.coli as contributors to the arsenic enriched SEED functions. Further genome annotation of the E.coli genome revealed two strains containing two different arsenic resistance operons that are not present in the gut microbiome of a recently described European human cohort (Metagenomics of the Human Intestinal Tract, MetaHIT). We then performed quantification by qPCR of two arsenic resistant genes (ArsB, ArsC). We observed that the expression of these two operons was higher among the children with high arsenic exposure compared to matched controls. This preliminary study indicates that arsenic exposure early in life was associated with altered gut microbiota in Bangladeshi children. The enrichment of E.coli arsenic resistance genes in the high exposure group provides an insight into the possible mechanisms of how this toxic compound could affect gut microbiota.

  11. Mutational analysis of the human nucleotide excision repair gene ERCC1.

    NARCIS (Netherlands)

    A.M. Sijbers (Anneke); P.J. van der Spek (Peter); H. Odijk (Hanny); J.H. van den Berg (Jan); M. van Duin (Mark); A. Westerveld (Andries); N.G.J. Jaspers (Nicolaas); D. Bootsma (Dirk); J.H.J. Hoeijmakers (Jan)

    1996-01-01

    textabstractThe human DNA repair protein ERCC1 resides in a complex together with the ERCC4, ERCC11 and XP-F correcting activities, thought to perform the 5' strand incision during nucleotide excision repair (NER). Its yeast counterpart, RAD1-RAD10, has an additional engagement in a mitotic

  12. Repair genes expression profile of MLH1, MSH2 and ATM in the normal oral mucosa of chronic smokers.

    Science.gov (United States)

    Alves, Mônica Ghislaine Oliveira; Carta, Celina Faig Lima; de Barros, Patrícia Pimentel; Issa, Jaqueline Scholz; Nunes, Fábio Daumas; Almeida, Janete Dias

    2017-01-01

    The aim of this study was to evaluate the effect of chronic smoking on the expression profile of the repair genes MLH1, MSH2 and ATM in the normal oral mucosa of chronic smokers and never smokers. The sample consisted of thirty exfoliative cytology smears per group obtained from Smokers and Never Smokers. Total RNA was extracted and expression of the MLH1, MSH2 and ATM genes were evaluated by quantitative real-time and immunocytochemistry. The gene and protein expression data were correlated to the clinical data. Gene expression was analyzed statistically using the Student t-test and Pearson's correlation coefficient, with pATM genes were downregulated in the smoking group compared to the control with significant values for MLH1 (p=0.006), MSH2 (p=0.0001) and ATM (p=0.0001). Immunocytochemical staining for anti-MLH1, anti-MSH2 and anti-ATM was negative in Never Smokers; in Smokers it was rarely positive. No significant correlation was observed among the expression of MLH1, MSH2, ATM and age, number of cigarettes consumed per day, time of smoking during life, smoking history or levels of CO in expired air. The expression of genes and proteins related to DNA repair mechanism MLH1, MSH2 and ATM in the normal oral mucosa of chronic smokers was reduced. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. The Mutyh base excision repair gene influences the inflammatory response in a mouse model of ulcerative colitis.

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    Ida Casorelli

    Full Text Available BACKGROUND: The Mutyh DNA glycosylase is involved in the repair of oxidized DNA bases. Mutations in the human MUTYH gene are responsible for colorectal cancer in familial adenomatous polyposis. Since defective DNA repair genes might contribute to the increased cancer risk associated with inflammatory bowel diseases, we compared the inflammatory response of wild-type and Mutyh(-/- mice to oxidative stress. METHODOLOGY/PRINCIPAL FINDINGS: The severity of colitis, changes in expression of genes involved in DNA repair and inflammation, DNA 8-oxoguanine levels and microsatellite instability were analysed in colon of mice treated with dextran sulfate sodium (DSS. The Mutyh(-/- phenotype was associated with a significant accumulation of 8-oxoguanine in colon DNA of treated mice. A single DSS cycle induced severe acute ulcerative colitis in wild-type mice, whereas lesions were modest in Mutyh(-/- mice, and this was associated with moderate variations in the expression of several cytokines. Eight DSS cycles caused chronic colitis in both wild-type and Mutyh(-/- mice. Lymphoid hyperplasia and a significant reduction in Foxp3(+ regulatory T cells were observed only in Mutyh(-/- mice. CONCLUSIONS: The findings indicate that, in this model of ulcerative colitis, Mutyh plays a major role in maintaining intestinal integrity by affecting the inflammatory response.

  14. Knockout targeting of the Drosophila nap1 gene and examination of DNA repair tracts in the recombination products.

    Science.gov (United States)

    Lankenau, Susanne; Barnickel, Thorsten; Marhold, Joachim; Lyko, Frank; Mechler, Bernard M; Lankenau, Dirk-Henner

    2003-02-01

    We used ends-in gene targeting to generate knockout mutations of the nucleosome assembly protein 1 (Nap1) gene in Drosophila melanogaster. Three independent targeted null-knockout mutations were produced. No wild-type NAP1 protein could be detected in protein extracts. Homozygous Nap1(KO) knockout flies were either embryonic lethal or poorly viable adult escapers. Three additional targeted recombination products were viable. To gain insight into the underlying molecular processes we examined conversion tracts in the recombination products. In nearly all cases the I-SceI endonuclease site of the donor vector was replaced by the wild-type Nap1 sequence. This indicated exonuclease processing at the site of the double-strand break (DSB), followed by replicative repair at donor-target junctions. The targeting products are best interpreted either by the classical DSB repair model or by the break-induced recombination (BIR) model. Synthesis-dependent strand annealing (SDSA), which is another important recombinational repair pathway in the germline, does not explain ends-in targeting products. We conclude that this example of gene targeting at the Nap1 locus provides added support for the efficiency of this method and its usefulness in targeting any arbitrary locus in the Drosophila genome.

  15. Polymorphisms in DNA repair genes, smoking, and bladder cancer risk: findings from the International Consortium of Bladder Cancer

    Science.gov (United States)

    Stern, Mariana C.; Lin, Jie; Figueroa, Jonine D.; Kelsey, Karl T.; Kiltie, Anne E.; Yuan, Jian-Min; Matullo, Giuseppe; Fletcher, Tony; Benhamou, Simone; Taylor, Jack A.; Placidi, Donatella; Zhang, Zuo-Feng; Steineck, Gunnar; Rothman, Nathaniel; Kogevinas, Manolis; Silverman, Debra; Malats, Nuria; Chanock, Stephen; Wu, Xifeng; Karagas, Margaret R.; Andrew, Angeline S.; Nelson, Heather H.; Bishop, D. Timothy; Sak, Sei Chung; Choudhury, Ananya; Barrett, Jennifer H; Elliot, Faye; Corral, Román; Joshi, Amit D.; Gago-Dominguez, Manuela; Cortessis, Victoria K.; Xiang, Yong-Bing; Vineis, Paolo; Sacerdote, Carlotta; Guarrera, Simonetta; Polidoro, Silvia; Allione, Alessandra; Gurzau, Eugen; Koppova, Kvetoslava; Kumar, Rajiv; Rudnai, Peter; Porru, Stefano; Carta, Angela; Campagna, Marcello; Arici, Cecilia; Park, SungShim Lani; Garcia-Closas, Montserrat

    2009-01-01

    Tobacco smoking is the most important and well-established bladder cancer risk factor, and a rich source of chemical carcinogens and reactive oxygen species that can induce damage to DNA in urothelial cells. Therefore, common variation in DNA repair genes might modify bladder cancer risk. In this study we present results from meta- and pooled analyses conducted as part of the International Consortium of Bladder Cancer. We included data on 10 single nucleotide polymorphisms corresponding to 7 DNA repair genes from 13 studies. Pooled- and meta-analyses included 5,282 cases and 5,954 controls of non-Latino white origin. We found evidence for weak but consistent associations with ERCC2 D312N (rs1799793) (per allele OR = 1.10; 95% CI = 1.01–1.19; p = 0.021), NBN E185Q (rs1805794) (per allele OR = 1.09; 95% CI = 1.01–1.18; p = 0.028), and XPC A499V (rs2228000) (per allele OR = 1.10; 95% CI = 1.00–1.21, p = 0.044). The association with NBN E185Q was limited to ever smokers (interaction p = 0.002), and was strongest for the highest levels of smoking dose and smoking duration. Overall, our study provides the strongest evidence to date for a role of common variants in DNA repair genes in bladder carcinogenesis. PMID:19706757

  16. The repair of melphalan-induced DNA adducts in the transcribed strand of active genes is subject to a strong polarity effect.

    OpenAIRE

    Episkopou, Hara; Kyrtopoulos, Soterios A.; Sfikakis, Petros P.; Meletios A Dimopoulos; Souliotis, Vassilis L

    2011-01-01

    To investigate the mechanisms of the therapeutic action and drug resistance to the nitrogen mustard melphalan, melphalan-induced DNA damage repair and chromatin structure were examined along the p53, N-ras and d-globin gene loci in cells carrying different repair activities. In nucleotide excision repair-deficient XP-A cells, similar levels of adducts were found in all fragments examined, indicating uniform distribution of DNA damage. In both, repair-proficient CS-B and XP-C cells, faster rep...

  17. Human longevity and variation in DNA damage response and repair: Study of the contribution of sub-processes using competitive gene-set analysis

    DEFF Research Database (Denmark)

    Debrabant, Birgit; Sørensen, Mette; Flachsbart, Friederike

    2014-01-01

    others. Data were applied on 592 SNPs from 77 genes involved in nine sub-processes: DNA-damage response, base excision repair (BER), nucleotide excision repair, mismatch repair, non-homologous end-joining, homologous recombinational repair (HRR), RecQ helicase activities (RECQ), telomere functioning...... and mitochondrial DNA processes. The study population was 1089 long-lived and 736 middle-aged Danes. A self-contained set-based test of all SNPs displayed association with longevity (P-value=9.9 × 10-5), supporting that the overall pathway could affect longevity. Investigation of the nine sub-processes using...

  18. Alcohol Consumption and the Risk of Colorectal Cancer for Mismatch Repair Gene Mutation Carriers.

    Science.gov (United States)

    Dashti, S Ghazaleh; Buchanan, Daniel D; Jayasekara, Harindra; Ait Ouakrim, Driss; Clendenning, Mark; Rosty, Christophe; Winship, Ingrid M; Macrae, Finlay A; Giles, Graham G; Parry, Susan; Casey, Graham; Haile, Robert W; Gallinger, Steven; Le Marchand, Loïc; Thibodeau, Stephen N; Lindor, Noralane M; Newcomb, Polly A; Potter, John D; Baron, John A; Hopper, John L; Jenkins, Mark A; Win, Aung Ko

    2017-03-01

    Background: People with germline mutation in one of the DNA mismatch repair (MMR) genes have increased colorectal cancer risk. For these high-risk people, study findings of the relationship between alcohol consumption and colorectal cancer risk have been inconclusive. Methods: 1,925 MMR gene mutations carriers recruited into the Colon Cancer Family Registry who had completed a questionnaire on lifestyle factors were included. Weighted Cox proportional hazard regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between alcohol consumption and colorectal cancer. Results: Colorectal cancer was diagnosed in 769 carriers (40%) at a mean (SD) age of 42.6 (10.3) years. Compared with abstention, ethanol consumption from any alcoholic beverage up to 14 g/day and >28 g/day was associated with increased colorectal cancer risk (HR, 1.50; 95% CI, 1.09-2.07 and 1.69; 95% CI, 1.07-2.65, respectively; P trend = 0.05), and colon cancer risk (HR, 1.78; 95% CI, 1.27-2.49 and 1.94; 95% CI, 1.19-3.18, respectively; P trend = 0.02). However, there was no clear evidence for an association with rectal cancer risk. Also, there was no evidence for associations between consumption of individual alcoholic beverage types (beer, wine, spirits) and colorectal, colon, or rectal cancer risk. Conclusions: Our data suggest that alcohol consumption, particularly more than 28 g/day of ethanol (∼2 standard drinks of alcohol in the United States), is associated with increased colorectal cancer risk for MMR gene mutation carriers. Impact: Although these data suggested that alcohol consumption in MMR carriers was associated with increased colorectal cancer risk, there was no evidence of a dose-response, and not all types of alcohol consumption were associated with increased risk. Cancer Epidemiol Biomarkers Prev; 26(3); 366-75. ©2016 AACR . ©2016 American Association for Cancer Research.

  19. Transplantation of erythropoietin gene-modified neural stem cells improves the repair of injured spinal cord

    Directory of Open Access Journals (Sweden)

    Min-fei Wu

    2015-01-01

    Full Text Available The protective effects of erythropoietin on spinal cord injury have not been well described. Here, the eukaryotic expression plasmid pcDNA3.1 human erythropoietin was transfected into rat neural stem cells cultured in vitro. A rat model of spinal cord injury was established using a free falling object. In the human erythropoietin-neural stem cells group, transfected neural stem cells were injected into the rat subarachnoid cavity, while the neural stem cells group was injected with non-transfected neural stem cells. Dulbecco′s modified Eagle′s medium/F12 medium was injected into the rats in the spinal cord injury group as a control. At 1-4 weeks post injury, the motor function in the rat lower limbs was best in the human erythropoietin-neural stem cells group, followed by the neural stem cells group, and lastly the spinal cord injury group. At 72 hours, compared with the spinal cord injury group, the apoptotic index and Caspase-3 gene and protein expressions were apparently decreased, and the bcl-2 gene and protein expressions were noticeably increased, in the tissues surrounding the injured region in the human erythropoietin-neural stem cells group. At 4 weeks, the cavities were clearly smaller and the motor and somatosensory evoked potential latencies were remarkably shorter in the human erythropoietin-neural stem cells group and neural stem cells group than those in the spinal cord injury group. These differences were particularly obvious in the human erythropoietin-neural stem cells group. More CM-Dil-positive cells and horseradish peroxidase-positive nerve fibers and larger amplitude motor and somatosensory evoked potentials were found in the human erythropoietin-neural stem cells group and neural stem cells group than in the spinal cord injury group. Again, these differences were particularly obvious in the human erythropoietin-neural stem cells group. These data indicate that transplantation of erythropoietin gene-modified neural stem

  20. Transplantation of erythropoietin gene-modified neural stem cells improves the repair of injured spinal cord.

    Science.gov (United States)

    Wu, Min-Fei; Zhang, Shu-Quan; Gu, Rui; Liu, Jia-Bei; Li, Ye; Zhu, Qing-San

    2015-09-01

    The protective effects of erythropoietin on spinal cord injury have not been well described. Here, the eukaryotic expression plasmid pcDNA3.1 human erythropoietin was transfected into rat neural stem cells cultured in vitro. A rat model of spinal cord injury was established using a free falling object. In the human erythropoietin-neural stem cells group, transfected neural stem cells were injected into the rat subarachnoid cavity, while the neural stem cells group was injected with non-transfected neural stem cells. Dulbecco's modified Eagle's medium/F12 medium was injected into the rats in the spinal cord injury group as a control. At 1-4 weeks post injury, the motor function in the rat lower limbs was best in the human erythropoietin-neural stem cells group, followed by the neural stem cells group, and lastly the spinal cord injury group. At 72 hours, compared with the spinal cord injury group, the apoptotic index and Caspase-3 gene and protein expressions were apparently decreased, and the bcl-2 gene and protein expressions were noticeably increased, in the tissues surrounding the injured region in the human erythropoietin-neural stem cells group. At 4 weeks, the cavities were clearly smaller and the motor and somatosensory evoked potential latencies were remarkably shorter in the human erythropoietin-neural stem cells group and neural stem cells group than those in the spinal cord injury group. These differences were particularly obvious in the human erythropoietin-neural stem cells group. More CM-Dil-positive cells and horseradish peroxidase-positive nerve fibers and larger amplitude motor and somatosensory evoked potentials were found in the human erythropoietin-neural stem cells group and neural stem cells group than in the spinal cord injury group. Again, these differences were particularly obvious in the human erythropoietin-neural stem cells group. These data indicate that transplantation of erythropoietin gene-modified neural stem cells into the

  1. Germ line mutations of mismatch repair genes in hereditary nonpolyposis colorectal cancer patients with small bowel cancer: International Society for Gastrointestinal Hereditary Tumours Collaborative Study

    DEFF Research Database (Denmark)

    Park, Jae-Gahb; Kim, Duck-Woo; Hong, Chang Won

    2006-01-01

    PURPOSE: The aim of study was to determine the clinical characteristics and mutational profiles of the mismatch repair genes in hereditary nonpolyposis colorectal cancer (HNPCC) patients with small bowel cancer (SBC). EXPERIMENTAL DESIGN: A questionnaire was mailed to 55 members...... of the International Society for Gastrointestinal Hereditary Tumours, requesting information regarding patients with HNPCC-associated SBC and germ line mismatch repair gene mutations. RESULTS: The study population consisted of 85 HNPCC patients with identified mismatch repair gene mutations and SBCs. SBC was the first...... HNPCC-associated malignancy in 14 of 41 (34.1%) patients for whom a personal history of HNPCC-associated cancers was available. The study population harbored 69 different germ line mismatch repair gene mutations, including 31 mutations in MLH1, 34 in MSH2, 3 in MSH6, and 1 in PMS2. We compared...

  2. Single-Nucleotide Polymorphisms of Genes Involved in Repair of Oxidative DNA Damage and the Risk of Recurrent Depressive Disorder

    Science.gov (United States)

    Czarny, Piotr; Kwiatkowski, Dominik; Toma, Monika; Gałecki, Piotr; Orzechowska, Agata; Bobińska, Kinga; Bielecka-Kowalska, Anna; Szemraj, Janusz; Berk, Michael; Anderson, George; Śliwiński, Tomasz

    2016-01-01

    Background Depressive disorder, including recurrent type (rDD), is accompanied by increased oxidative stress and activation of inflammatory pathways, which may induce DNA damage. This thesis is supported by the presence of increased levels of DNA damage in depressed patients. Such DNA damage is repaired by the base excision repair (BER) pathway. BER efficiency may be influenced by polymorphisms in BER-related genes. Therefore, we genotyped nine single-nucleotide polymorphisms (SNPs) in six genes encoding BER proteins. Material/Methods Using TaqMan, we selected and genotyped the following SNPs: c.-441G>A (rs174538) of FEN1, c.2285T>C (rs1136410) of PARP1, c.580C>T (rs1799782) and c.1196A>G (rs25487) of XRCC1, c.*83A>C (rs4796030) and c.*50C>T (rs1052536) of LIG3, c.-7C>T (rs20579) of LIG1, and c.-468T>G (rs1760944) and c.444T>G (rs1130409) of APEX1 in 599 samples (288 rDD patients and 311 controls). Results We found a strong correlation between rDD and both SNPs of LIG3, their haplotypes, as well as a weaker association with the c.-468T>G of APEXI which diminished after Nyholt correction. Polymorphisms of LIG3 were also associated with early onset versus late onset depression, whereas the c.-468T>G polymorphism showed the opposite association. Conclusions The SNPs of genes involved in the repair of oxidative DNA damage may modulate rDD risk. Since this is an exploratory study, the results should to be treated with caution and further work needs to be done to elucidate the exact involvement of DNA damage and repair mechanisms in the development of this disease. PMID:27866211

  3. Single-Nucleotide Polymorphisms of Genes Involved in Repair of Oxidative DNA Damage and the Risk of Recurrent Depressive Disorder.

    Science.gov (United States)

    Czarny, Piotr; Kwiatkowski, Dominik; Toma, Monika; Gałecki, Piotr; Orzechowska, Agata; Bobińska, Kinga; Bielecka-Kowalska, Anna; Szemraj, Janusz; Berk, Michael; Anderson, George; Śliwiński, Tomasz

    2016-11-20

    BACKGROUND Depressive disorder, including recurrent type (rDD), is accompanied by increased oxidative stress and activation of inflammatory pathways, which may induce DNA damage. This thesis is supported by the presence of increased levels of DNA damage in depressed patients. Such DNA damage is repaired by the base excision repair (BER) pathway. BER efficiency may be influenced by polymorphisms in BER-related genes. Therefore, we genotyped nine single-nucleotide polymorphisms (SNPs) in six genes encoding BER proteins. MATERIAL AND METHODS Using TaqMan, we selected and genotyped the following SNPs: c.-441G>A (rs174538) of FEN1, c.2285T>C (rs1136410) of PARP1, c.580C>T (rs1799782) and c.1196A>G (rs25487) of XRCC1, c.*83A>C (rs4796030) and c.*50C>T (rs1052536) of LIG3, c.-7C>T (rs20579) of LIG1, and c.-468T>G (rs1760944) and c.444T>G (rs1130409) of APEX1 in 599 samples (288 rDD patients and 311 controls). RESULTS We found a strong correlation between rDD and both SNPs of LIG3, their haplotypes, as well as a weaker association with the c.-468T>G of APEXI which diminished after Nyholt correction. Polymorphisms of LIG3 were also associated with early onset versus late onset depression, whereas the c.-468T>G polymorphism showed the opposite association. CONCLUSIONS The SNPs of genes involved in the repair of oxidative DNA damage may modulate rDD risk. Since this is an exploratory study, the results should to be treated with caution and further work needs to be done to elucidate the exact involvement of DNA damage and repair mechanisms in the development of this disease.

  4. Antioxidative dietary compounds modulate gene expression associated with apoptosis, DNA repair, inhibition of cell proliferation and migration.

    Science.gov (United States)

    Wang, Likui; Gao, Shijuan; Jiang, Wei; Luo, Cheng; Xu, Maonian; Bohlin, Lars; Rosendahl, Markus; Huang, Wenlin

    2014-09-15

    Many dietary compounds are known to have health benefits owing to their antioxidative and anti-inflammatory properties. To determine the molecular mechanism of these food-derived compounds, we analyzed their effect on various genes related to cell apoptosis, DNA damage and repair, oxidation and inflammation using in vitro cell culture assays. This review further tests the hypothesis proposed previously that downstream products of COX-2 (cyclooxygenase-2) called electrophilic oxo-derivatives induce antioxidant responsive elements (ARE), which leads to cell proliferation under antioxidative conditions. Our findings support this hypothesis and show that cell proliferation was inhibited when COX-2 was down-regulated by polyphenols and polysaccharides. Flattened macrophage morphology was also observed following the induction of cytokine production by polysaccharides extracted from viili, a traditional Nordic fermented dairy product. Coix lacryma-jobi (coix) polysaccharides were found to reduce mitochondrial membrane potential and induce caspase-3- and 9-mediated apoptosis. In contrast, polyphenols from blueberries were involved in the ultraviolet-activated p53/Gadd45/MDM2 DNA repair system by restoring the cell membrane potential. Inhibition of hypoxia-inducible factor-1 by saponin extracts of ginsenoside (Ginsen) and Gynostemma and inhibition of S100A4 by coix polysaccharides inhibited cancer cell migration and invasion. These observations suggest that antioxidants and changes in cell membrane potential are the major driving forces that transfer signals through the cell membrane into the cytosol and nucleus, triggering gene expression, changes in cell proliferation and the induction of apoptosis or DNA repair.

  5. Homology Requirements and Competition between Gene Conversion and Break-Induced Replication during Double-Strand Break Repair.

    Science.gov (United States)

    Mehta, Anuja; Beach, Annette; Haber, James E

    2017-02-02

    Saccharomyces cerevisiae mating-type switching is initiated by a double-strand break (DSB) at MATa, leaving one cut end perfectly homologous to the HMLα donor, while the second end must be processed to remove a non-homologous tail before completing repair by gene conversion (GC). When homology at the matched end is ≤150 bp, efficient repair depends on the recombination enhancer, which tethers HMLα near the DSB. Thus, homology shorter than an apparent minimum efficient processing segment can be rescued by tethering the donor near the break. When homology at the second end is ≤150 bp, second-end capture becomes inefficient and repair shifts from GC to break-induced replication (BIR). But when pol32 or pif1 mutants block BIR, GC increases 3-fold, indicating that the steps blocked by these mutations are reversible. With short second-end homology, absence of the RecQ helicase Sgs1 promotes gene conversion, whereas deletion of the FANCM-related Mph1 helicase promotes BIR. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Yeast DNA-repair gene RAD14 encodes a zinc metalloprotein with affinity for ultraviolet-damaged DNA.

    Science.gov (United States)

    Guzder, S N; Sung, P; Prakash, L; Prakash, S

    1993-06-15

    Xeroderma pigmentosum (XP) patients suffer from a high incidence of skin cancers due to a defect in excision repair of UV light-damaged DNA. Of the seven XP complementation groups, A-G, group A represents a severe and frequent form of the disease. The Saccharomyces cerevisiae RAD14 gene is a homolog of the XP-A correcting (XPAC) gene. Like XP-A cells, rad14-null mutants are defective in the incision step of excision repair of UV-damaged DNA. We have purified RAD14 protein to homogeneity from extract of a yeast strain genetically tailored to overexpress RAD14. As determined by atomic emission spectroscopy, RAD14 contains one zinc atom. We also show in vitro that RAD14 binds zinc but does not bind other divalent metal ions. In DNA mobility-shift assays, RAD14 binds specifically to UV-damaged DNA. Removal of cyclobutane pyrimidine dimers from damaged DNA by enzymatic photoreactivation has no effect on binding, strongly suggesting that RAD14 recognizes pyrimidine(6-4)pyrimidone photoproduct sites. These findings indicate that RAD14 functions in damage recognition during excision repair.

  7. Evaluation of cell proliferation, apoptosis, and DNA-repair genes as potential biomarkers for ethanol-induced CNS alterations.

    Science.gov (United States)

    Hicks, Steven D; Lewis, Lambert; Ritchie, Julie; Burke, Patrick; Abdul-Malak, Ynesse; Adackapara, Nyssa; Canfield, Kelly; Shwarts, Erik; Gentile, Karen; Meszaros, Zsuzsa Szombathyne; Middleton, Frank A

    2012-10-25

    Alcohol use disorders (AUDs) lead to alterations in central nervous system (CNS) architecture along with impaired learning and memory. Previous work from our group and that of others suggests that one mechanism underlying these changes is alteration of cell proliferation, apoptosis, and DNA-repair in neural stem cells (NSCs) produced as a consequence of ethanol-induced effects on the expression of genes related to p53-signaling. This study tests the hypothesis that changes in the expression of p53-signaling genes represent biomarkers of ethanol abuse which can be identified in the peripheral blood of rat drinking models and human AUD subjects and posits that specific changes may be correlated with differences in neuropsychological measures and CNS structure. Remarkably, microarray analysis of 350 genes related to p53-signaling in peripheral blood leukocytes (PBLs) of binge-drinking rats revealed 190 genes that were significantly altered after correcting for multiple testing. Moreover, 40 of these genes overlapped with those that we had previously observed to be changed in ethanol-exposed mouse NSCs. Expression changes in nine of these genes were tested for independent confirmation by a custom QuantiGene Plex (QGP) assay for a subset of p53-signaling genes, where a consistent trend for decreased expression of mitosis-related genes was observed. One mitosis-related gene (Pttg1) was also changed in human lymphoblasts cultured with ethanol. In PBLs of human AUD subjects seven p53-signaling genes were changed compared with non-drinking controls. Correlation and principal components analysis were then used to identify significant relationships between the expression of these seven genes and a set of medical, demographic, neuropsychological and neuroimaging measures that distinguished AUD and control subjects. Two genes (Ercc1 and Mcm5) showed a highly significant correlation with AUD-induced decreases in the volume of the left parietal supramarginal gyrus and

  8. Evaluation of cell proliferation, apoptosis, and dna-repair genes as potential biomarkers for ethanol-induced cns alterations

    Directory of Open Access Journals (Sweden)

    Hicks Steven D

    2012-10-01

    Full Text Available Abstract Background Alcohol use disorders (AUDs lead to alterations in central nervous system (CNS architecture along with impaired learning and memory. Previous work from our group and that of others suggests that one mechanism underlying these changes is alteration of cell proliferation, apoptosis, and DNA-repair in neural stem cells (NSCs produced as a consequence of ethanol-induced effects on the expression of genes related to p53-signaling. This study tests the hypothesis that changes in the expression of p53-signaling genes represent biomarkers of ethanol abuse which can be identified in the peripheral blood of rat drinking models and human AUD subjects and posits that specific changes may be correlated with differences in neuropsychological measures and CNS structure. Results Remarkably, microarray analysis of 350 genes related to p53-signaling in peripheral blood leukocytes (PBLs of binge-drinking rats revealed 190 genes that were significantly altered after correcting for multiple testing. Moreover, 40 of these genes overlapped with those that we had previously observed to be changed in ethanol-exposed mouse NSCs. Expression changes in nine of these genes were tested for independent confirmation by a custom QuantiGene Plex (QGP assay for a subset of p53-signaling genes, where a consistent trend for decreased expression of mitosis-related genes was observed. One mitosis-related gene (Pttg1 was also changed in human lymphoblasts cultured with ethanol. In PBLs of human AUD subjects seven p53-signaling genes were changed compared with non-drinking controls. Correlation and principal components analysis were then used to identify significant relationships between the expression of these seven genes and a set of medical, demographic, neuropsychological and neuroimaging measures that distinguished AUD and control subjects. Two genes (Ercc1 and Mcm5 showed a highly significant correlation with AUD-induced decreases in the volume of the left

  9. Deficiency in nucleotide excision repair family gene activity, especially ERCC3, is associated with non-pigmented hair fiber growth.

    Directory of Open Access Journals (Sweden)

    Mei Yu

    Full Text Available We conducted a microarray study to discover gene expression patterns associated with a lack of melanogenesis in non-pigmented hair follicles (HF by microarray. Pigmented and non-pigmented HFs were collected and micro-dissected into the hair bulb (HB and the upper hair sheaths (HS including the bulge region. In comparison to pigmented HS and HBs, nucleotide excision repair (NER family genes ERCC1, ERCC2, ERCC3, ERCC4, ERCC5, ERCC6, XPA, NTPBP, HCNP, DDB2 and POLH exhibited statistically significantly lower expression in non- pigmented HS and HBs. Quantitative PCR verified microarray data and identified ERCC3 as highly differentially expressed. Immunohistochemistry confirmed ERCC3 expression in HF melanocytes. A reduction in ERCC3 by siRNA interference in human melanocytes in vitro reduced their tyrosinase production ability. Our results suggest that loss of NER gene function is associated with a loss of melanin production capacity. This may be due to reduced gene transcription and/or reduced DNA repair in melanocytes which may eventually lead to cell death. These results provide novel information with regard to melanogenesis and its regulation.

  10. Earth Abides Arsenic Biotransformations

    OpenAIRE

    Zhu, Yong-Guan; Yoshinaga, Masafumi; Zhao, Fang-Jie; Rosen, Barry P.

    2014-01-01

    Arsenic is the most prevalent environmental toxic element and causes health problems throughout the world. The toxicity, mobility, and fate of arsenic in the environment are largely determined by its speciation, and arsenic speciation changes are driven, at least to some extent, by biological processes. In this article, biotransformation of arsenic is reviewed from the perspective of the formation of Earth and the evolution of life, and the connection between arsenic geochemistry and biology ...

  11. Traditional Chinese Medicine Curcumin Sensitizes Human Colon Cancer to Radiation by Altering the Expression of DNA Repair-related Genes.

    Science.gov (United States)

    Yang, Guangen; Qiu, Jianming; Wang, Dong; Tao, Yong; Song, Yihuan; Wang, Hongtao; Tang, Juping; Wang, Xing; Sun, Y U; Yang, Zhijian; Hoffman, Robert M

    2018-01-01

    The aim of the present study was to investigate the radio-sensitizing efficacy of curcumin, a traditional Chinese medicine (TCM) on colon cancer cells in vitro and in vivo. Human colon cancer HT-29 cells were treated with curcumin (2.5 μM), irradiation (10 Gy) and the combination of irradiation and curcumin. Cell proliferation was assessed using the MTT assay. Apoptotic cells were detected by Annexin V-PE/7-AAD analysis. PCR was performed to determine differential-expression profiling of 95 DNA-repair genes in irradiated cells and cells treated with both irradiation and curcumin. Differentially-expressed genes were confirmed by Western blotting. In vivo radio-sensitizing efficacy of curcumin was assessed in a xenograft mouse model of HT-29 colon cancer. Curcumin was administrated daily by intraperitoneal injection at 20 mg/kg/dose. Mice received irradiation (10 Gy) twice weekly. Apoptosis of the cancer cells following treatment was determined by TUNEL staining. Irradiation induced proliferation inhibition and apoptosis of HT-29 cells in vitro. Concurrent curcumin treatment sensitized the HT-29 tumor to irradiation (p<0.01). DNA repair-related genes CCNH and XRCC5 were upregulated and LIG4 and PNKP downregulated by the combination of curcumin and irradiation compared with irradiation alone (p<0.05). Combined treatment of curcumin and irradiation resulted in a significantly greater tumor-growth inhibition and apoptosis compared to irradiation treatment alone (p<0.01). Curcumin sensitizes human colon cancer in vitro and in vivo to radiation. Downregulation of LIG4 and PNKP and upregulation of XRCC5 and CCNH DNA-repair-related genes were involved in the radio-sensitizing efficacy of curcumin in colon cancer. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  12. A mutation in the XPB/ERCC3 DNA repair transcription gene, associated with trichothiodystrophy

    Energy Technology Data Exchange (ETDEWEB)

    Weeda, G.; Donker, I.; Vermeulen, W. [Erasmus Univ., Rotterdam (Netherlands)] [and others

    1997-02-01

    Trichothiodystrophy (TTD) is a rare, autosomal recessive disorder characterized by sulfur-deficient brittle hair and nails, mental retardation, impaired sexual development, and ichthyosis. Photosensitivity has been reported in {approximately}50% of the cases, but no skin cancer is associated with TTD. Virtually all photosensitive TTD patients have a deficiency in the nucleotide excision repair (NER) of UV-induced DNA damage that is indistinguishable from that of xeroderma pigmentosum (XP) complementation group D (XP-D) patients. DNA repair defects in XP-D are associated with two additional, quite different diseases; XP, a sun-sensitive and cancer-prone repair disorder, and Cockayne syndrome (CS), a photosensitive condition characterized by physical and mental retardation and wizened facial appearance. One photosensitive TTD case constitutes a new repair-deficient complementation group, TTD-A. Remarkably, both TTD-A and XP-D defects are associated with subunits of TFIIH, a basal transcription factor with a second function in DNA repair. Thus, mutations in TFIIH components may, on top of a repair defect, also cause transcriptional insufficiency, which may explain part of the non-XP clinical features of TTD. To date, three patients with the remarkable conjunction of XP and CS but not TM have been assigned to XP complementation group B (XP-B). Here we present the characterization of the NER defect in two mild TTD patients (TTD6VI and TTD4VI) and confirm the assignment to X-PB. The causative mutation was found to be a single base substitution resulting in a missense mutation (T119P) in a region of the XPB protein. These findings define a third TTD complementation group, extend the clinical heterogeneity associated with XP-B, stress the exclusive relationship between TTD and mutations in subunits of repair/transcription factor TFIIH, and strongly support the concept of {open_quotes}transcription syndromes.{close_quotes} 46 refs., 6 figs., 2 tabs.

  13. PAH-DNA adducts in environmentally exposed population in relation to metabolic and DNA repair gene polymorphisms

    Energy Technology Data Exchange (ETDEWEB)

    Binkova, Blanka [Laboratory of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR and Health Institute of Central Bohemia, Videnska 1083, 14220 Prague (Czech Republic); Chvatalova, Irena [Laboratory of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR and Health Institute of Central Bohemia, Videnska 1083, 14220 Prague (Czech Republic); Lnenickova, Zdena [Laboratory of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR and Health Institute of Central Bohemia, Videnska 1083, 14220 Prague (Czech Republic); Milcova, Alena [Laboratory of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR and Health Institute of Central Bohemia, Videnska 1083, 14220 Prague (Czech Republic); Tulupova, Elena [Laboratory of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR and Health Institute of Central Bohemia, Videnska 1083, 14220 Prague (Czech Republic); Cancer Biomarkers and Prevention Group, Biocentre, University of Leicester (United Kingdom); Farmer, Peter B. [Cancer Biomarkers and Prevention Group, Biocentre, University of Leicester (United Kingdom); Sram, Radim J. [Laboratory of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR and Health Institute of Central Bohemia, Videnska 1083, 14220 Prague (Czech Republic)]. E-mail: sram@biomed.cas.cz

    2007-07-01

    Epidemiologic studies indicate that prolonged exposure to particulate air pollution may be associated with increased risk of cardiovascular diseases and cancer in general population. These effects may be attributable to polycyclic aromatic hydrocarbons (PAHs) adsorbed to respirable air particles. It is expected that metabolic and DNA repair gene polymorphisms may modulate individual susceptibility to PAH exposure. This study investigates relationships between exposure to PAHs, polymorphisms of these genes and DNA adducts in group of occupationally exposed policemen (EXP, N = 53, males, aged 22-50 years) working outdoors in the downtown area of Prague and in matched 'unexposed' controls (CON, N = 52). Personal exposure to eight carcinogenic PAHs (c-PAHs) was evaluated by personal samplers during working shift prior to collection of biological samples. Bulky-aromatic DNA adducts were analyzed in lymphocytes by {sup 32}P-postlabeling assay. Polymorphisms of metabolizing (GSTM1, GSTP1, GSTT1, EPHX1, CYP1A1-MspI) and DNA repair (XRCC1, XPD) genes were determined by PCR-based RFLP assays. As potential modifiers and/or cofounders, urinary cotinine levels were analyzed by radioimmunoassay, plasma levels of vitamins A, C, E and folates by HPLC, cholesterol and triglycerides using commercial kits. During the sampling period ambient particulate air pollution was as follows: PM10 32-55 {mu}g/m{sup 3}, PM2.5 27-38 {mu}g/m{sup 3}, c-PAHs 18-22 ng/m{sup 3}; personal exposure to c-PAHs: 9.7 ng/m{sup 3} versus 5.8 ng/m{sup 3} (P < 0.01) for EXP and CON groups, respectively. The total DNA adduct levels did not significantly differ between EXP and CON groups (0.92 {+-} 0.28 adducts/10{sup 8} nucleotides versus 0.82 {+-} 0.23 adducts/10{sup 8} nucleotides, P = 0.065), whereas the level of the B[a]P-'like' adduct was significantly higher in exposed group (0.122 {+-} 0.036 adducts/10{sup 8} nucleotides versus 0.099 {+-} 0.035 adducts/10{sup 8} nucleotides, P = 0

  14. Cloning, comparative mapping, and RNA expression of the mouse homologues of the Saccharomyces cerevisiae nucleotide excision repair gene RAD23

    Energy Technology Data Exchange (ETDEWEB)

    Spek, P.J. van der; Visser, C.E.; Bootsma, D. [Erasmus Univ., Rotterdam (Netherlands)] [and others

    1996-01-01

    The Saccharomyces cerevisiae RAD23 gene is involved in nucleotide excision repair (NER). Two human homologs of RAD23, HHR23A and HHR23B (HGMW-approved symbols RAD23A and RAD23B), were previously isolated. The HHR23B protein is complexed with the protein defective in the cancer-prone repair syndrome xeroderma pigmentosum, complementation group C, and is specifically involved in the global genome NER subpathway. The cloning of both mouse homologs (designated MHR23A and MHR23B) and detailed sequence comparison permitted the deduction of the following overall structure for all RAD23 homologs: an ubiquitin-like N-terminus followed by a strongly conserved 50-amino-acid domain that is repeated at the C-terminus. We also found this domain as a specific C-terminal extension of one of the ubiquitin-conjugating enzymes, providing a second link with the ubiquitin pathway. By means of in situ hybridization, MHR23A was assigned to mouse chromosome 8C3 and MHR23B to 4B3. Because of the close chromosomal proximity of human XPC and HHR23B, the mouse XPC chromosomal location was determined (6D). Physical disconnection of the genes in mouse argues against a functional significance of the colocalization of these genes in human. Northern blot analysis revealed constitutive expression of both MHR23 genes in all tissues examined. Elevated RNA expression of both MHR23 genes was observed in testis. Although the RAD23 equivalents are well conserved during evolution, the mammalian genes did not express the UV-inducible phenotype of their yeast counterpart. This may point to a fundamental difference between the UV responses of yeast and human. No stage-specific mRNA expression during the cell cycle was observed for the mammalian RAD23 homologs. 38 refs., 5 figs.

  15. Development-dependent expression of DNA repair genes and epigenetic regulators in Arabidopsis plants exposed to ionizing radiation.

    Science.gov (United States)

    Sidler, Corinne; Li, Dongping; Kovalchuk, Olga; Kovalchuk, Igor

    2015-02-01

    Both plant senescence and plant response to ionizing radiation involve changes in gene expression and epigenetic profiles, that rely on the formation of reactive oxygen species. However, how the developmental stage of a plant affects its response to ionizing radiation has not been extensively studied. In this study, our experiments showed that exposure to low (10 Gy) and high (100 Gy) doses of ionizing radiation causes developmental delays in plants that may result in reduced biomass or even death of the organism. In particular, 20-day-old plants, which are in the process of transitioning to reproductive growth, showed a distinct response to irradiation compared to 10- or 30-day-old irradiated plants that affects the expression of DNA repair genes. Specifically, we found that the expression of mismatch repair genes was increased in 20-day-old plants, while RAD51 was increased in 10- and 30-day-old plants. Furthermore, we found increased expression of MET1, CMT3 and SUVH5 epigenetic regulators that paralleled decreased ONSEN transcript levels in 20-day-old irradiated plants. These findings suggest that plants exposed during early reproductive growth exhibit a tighter control over genome stability in response to ionizing irradiation compared to plants irradiated at other developmental stages.

  16. Purkinje Cell Degeneration in pcd Mice Reveals Large Scale Chromatin Reorganization and Gene Silencing Linked to Defective DNA Repair*

    Science.gov (United States)

    Baltanás, Fernando C.; Casafont, Iñigo; Lafarga, Vanesa; Weruaga, Eduardo; Alonso, José R.; Berciano, María T.; Lafarga, Miguel

    2011-01-01

    DNA repair protects neurons against spontaneous or disease-associated DNA damage. Dysfunctions of this mechanism underlie a growing list of neurodegenerative disorders. The Purkinje cell (PC) degeneration mutation causes the loss of nna1 expression and is associated with the postnatal degeneration of PCs. This PC degeneration dramatically affects nuclear architecture and provides an excellent model to elucidate the nuclear mechanisms involved in a whole array of neurodegenerative disorders. We used immunocytochemistry for histone variants and components of the DNA damage response, an in situ transcription assay, and in situ hybridization for telomeres to analyze changes in chromatin architecture and function. We demonstrate that the phosphorylation of H2AX, a DNA damage signal, and the trimethylation of the histone H4K20, a repressive mark, in extensive domains of genome are epigenetic hallmarks of chromatin in degenerating PCs. These histone modifications are associated with a large scale reorganization of chromatin, telomere clustering, and heterochromatin-induced gene silencing, all of them key factors in PC degeneration. Furthermore, ataxia telangiectasia mutated and 53BP1, two components of the DNA repair pathway, fail to be concentrated in the damaged chromatin compartments, even though the expression levels of their coding genes were slightly up-regulated. Although the mechanism by which Nna1 loss of function leads to PC neurodegeneration is undefined, the progressive accumulation of DNA damage in chromosome territories irreversibly compromises global gene transcription and seems to trigger PC degeneration and death. PMID:21700704

  17. Purkinje cell degeneration in pcd mice reveals large scale chromatin reorganization and gene silencing linked to defective DNA repair.

    Science.gov (United States)

    Baltanás, Fernando C; Casafont, Iñigo; Lafarga, Vanesa; Weruaga, Eduardo; Alonso, José R; Berciano, María T; Lafarga, Miguel

    2011-08-12

    DNA repair protects neurons against spontaneous or disease-associated DNA damage. Dysfunctions of this mechanism underlie a growing list of neurodegenerative disorders. The Purkinje cell (PC) degeneration mutation causes the loss of nna1 expression and is associated with the postnatal degeneration of PCs. This PC degeneration dramatically affects nuclear architecture and provides an excellent model to elucidate the nuclear mechanisms involved in a whole array of neurodegenerative disorders. We used immunocytochemistry for histone variants and components of the DNA damage response, an in situ transcription assay, and in situ hybridization for telomeres to analyze changes in chromatin architecture and function. We demonstrate that the phosphorylation of H2AX, a DNA damage signal, and the trimethylation of the histone H4K20, a repressive mark, in extensive domains of genome are epigenetic hallmarks of chromatin in degenerating PCs. These histone modifications are associated with a large scale reorganization of chromatin, telomere clustering, and heterochromatin-induced gene silencing, all of them key factors in PC degeneration. Furthermore, ataxia telangiectasia mutated and 53BP1, two components of the DNA repair pathway, fail to be concentrated in the damaged chromatin compartments, even though the expression levels of their coding genes were slightly up-regulated. Although the mechanism by which Nna1 loss of function leads to PC neurodegeneration is undefined, the progressive accumulation of DNA damage in chromosome territories irreversibly compromises global gene transcription and seems to trigger PC degeneration and death.

  18. Beryllium chloride-induced oxidative DNA damage and alteration in the expression patterns of DNA repair-related genes.

    Science.gov (United States)

    Attia, Sabry M; Harisa, Gamaleldin I; Hassan, Memy H; Bakheet, Saleh A

    2013-09-01

    Beryllium metal has physical properties that make its use essential for very specific applications, such as medical diagnostics, nuclear/fusion reactors and aerospace applications. Because of the widespread human exposure to beryllium metals and the discrepancy of the genotoxic results in the reported literature, detail assessments of the genetic damage of beryllium are warranted. Mice exposed to beryllium chloride at an oral dose of 23mg/kg for seven consecutive days exhibited a significant increase in the level of DNA-strand breaking and micronuclei formation as detected by a bone marrow standard comet assay and micronucleus test. Whereas slight beryllium chloride-induced oxidative DNA damage was detected following formamidopyrimidine DNA glycosylase digestion, digestion with endonuclease III resulted in considerable increases in oxidative DNA damage after the 11.5 and 23mg/kg/day treatment as detected by enzyme-modified comet assays. Increased 8-hydroxydeoxyguanosine was also directly correlated with increased bone marrow micronuclei formation and DNA strand breaks, which further confirm the involvement of oxidative stress in the induction of bone marrow genetic damage after exposure to beryllium chloride. Gene expression analysis on the bone marrow cells from beryllium chloride-exposed mice showed significant alterations in genes associated with DNA damage repair. Therefore, beryllium chloride may cause genetic damage to bone marrow cells due to the oxidative stress and the induced unrepaired DNA damage is probably due to the down-regulation in the expression of DNA repair genes, which may lead to genotoxicity and eventually cause carcinogenicity.

  19. Molecular spectrum of excision repair cross-complementation group 8 gene defects in Chinese patients with Cockayne syndrome type A

    OpenAIRE

    Wang, Xiaozhu; Huang, Yu; Yan, Ming; Li, Jiuwei; Ding, Changhong; Jin, Hong; Fang, Fang; Yang, Yanling; Wu, Baiyan; Chen, Dafang

    2017-01-01

    There are two genetics complementary groups Cockayne syndrome type A and B (CS-A and CS-B OMIM 216400, 133540), which is a rare autosomal recessive segmental progeroid syndrome. Homozygous or compound heterozygous mutations in the excision repair cross-complementation group 8 gene (ERCC8) result in CS-A, and mutations in ERCC6 result in CS-B. Homozygous ERCC6/ERCC8 mutations also result in UV-sensitive syndrome. In this study, twenty-one Han Chinese patients with CS were investigated to ident...

  20. Radiation-Induced Upregulation of Gene Expression From Adenoviral Vectors Mediated by DNA Damage Repair and Regulation

    Energy Technology Data Exchange (ETDEWEB)

    Nokisalmi, Petri; Rajecki, Maria; Pesonen, Sari; Escutenaire, Sophie [Cancer Gene Therapy Group, Molecular Cancer Biology Program, Transplantation Laboratory, Haartman Institute, and Finnish Institute for Molecular Medicine, University of Helsinki, Helsinki (Finland); Helsinki and Uusimaa Hospital District Laboratory, Helsinki University Central Hospital, Helsinki (Finland); Soliymani, Rabah [Protein Chemistry Unit, Department of Anatomy, Institute of Biomedicine, Biomedicum Helsinki (Finland); Tenhunen, Mikko [Department of Radiation and Oncology, Helsinki University Central Hospital, Helsinki (Finland); Ahtiainen, Laura [Cancer Gene Therapy Group, Molecular Cancer Biology Program, Transplantation Laboratory, Haartman Institute, and Finnish Institute for Molecular Medicine, University of Helsinki, Helsinki (Finland); Helsinki and Uusimaa Hospital District Laboratory, Helsinki University Central Hospital, Helsinki (Finland); Hemminki, Akseli, E-mail: akseli.hemminki@helsinki.fi [Cancer Gene Therapy Group, Molecular Cancer Biology Program, Transplantation Laboratory, Haartman Institute, and Finnish Institute for Molecular Medicine, University of Helsinki, Helsinki (Finland); Helsinki and Uusimaa Hospital District Laboratory, Helsinki University Central Hospital, Helsinki (Finland)

    2012-05-01

    Purpose: In the present study, we evaluated the combination of replication-deficient adenoviruses and radiotherapy in vitro. The purpose of the present study was to analyze the mechanism of radiation-mediated upregulation of adenoviral transgene expression. Methods and Materials: Adenoviral transgene expression (luciferase or green fluorescent protein) was studied with and without radiation in three cell lines: breast cancer M4A4-LM3, prostate cancer PC-3MM2, and lung cancer LNM35/enhanced green fluorescent protein. The effect of the radiation dose, modification of the viral capsid, and five different transgene promoters were studied. The cellular responses were studied using mass spectrometry and immunofluorescence analysis. Double strand break repair was modulated by inhibitors of heat shock protein 90, topoisomerase-I, and DNA protein kinase, and transgene expression was measured. Results: We found that a wide range of radiation doses increased adenoviral transgene expression regardless of the cell line, transgene, promoter, or viral capsid modification. Treatment with adenovirus, radiation, and double strand break repair inhibitors resulted in persistence of double strand breaks and subsequent increases in adenovirus transgene expression. Conclusions: Radiation-induced enhancement of adenoviral transgene expression is linked to DNA damage recognition and repair. Radiation induces a global cellular response that results in increased production of RNA and proteins, including adenoviral transgene products. This study provides a mechanistic rationale for combining radiation with adenoviral gene delivery.

  1. DNA repair gene XRCC3 241Met variant and breast cancer susceptibility of Azeri population in Iranian

    Directory of Open Access Journals (Sweden)

    Gohari-Lasaki Sahar

    2015-01-01

    Full Text Available DNA-repair systems are essential for repairing damage that occurs when there is recombination between homologous chromosomes. The gene XRCC3 (X-ray cross complementing group 3 encodes a member of the RecA/Rad51-related protein family that participates in homologous recombination to maintain chromosome stability and repair DNA damage. The Thr241Met XRCC3-18067C>T, rs861539 substitution, a C to T transition at codon 241 in exon7, thus plays critical roles in cancer development. The aim of this study was association between XRCC3 Thr241Met polymorphism and risk of sporadic breast cancer in Azari population. We analysed DNA samples from 100 sporadic breast cancer patients and 100 healthy women, for XRCC3 Thr241Met polymorphism using PCR-RFLP. Genotype specific risks were tested using chi-test with 95% confident intervals. Frequency of Thr/Thr at codon 241was 69% in controls and 70% in patients, Thr/Met frequency was 22% in controls and 13 % in patients, the Met/Met genotype was 9% incontrols and 17% in patients. No correlation between the genotype and allele distribution and increased susceptibility for breast Cancer. Our results suggested that in pre-menopausal women, breast cancer riskis not significantly associated with rs861539 in Azari population.

  2. Delayed neuromotor recovery and increased memory acquisition dysfunction following experimental brain trauma in mice lacking the DNA repair gene XPA.

    Science.gov (United States)

    Tomasevic, Gregor; Laurer, Helmut L; Mattiasson, Gustav; van Steeg, Harry; Wieloch, Tadeusz; McIntosh, Tracy K

    2012-06-01

    This study investigates the outcome after traumatic brain injury (TBI) in mice lacking the essential DNA repair gene xeroderma pigmentosum group A (XPA). As damage to DNA has been implicated in neuronal cell death in various models, the authors sought to elucidate whether the absence of an essential DNA repair factor would affect the outcome of TBI in an experimental setting. Thirty-seven adult mice of either wild-type (n = 18) or XPA-deficient ("knock-out" [n = 19]) genotype were subjected to controlled cortical impact experimental brain trauma, which produced a focal brain injury. Sham-injured mice of both genotypes were used as controls (9 in each group). The mice were subjected to neurobehavoral tests evaluating learning/acquisition (Morris water maze) and motor dysfunction (Rotarod and composite neuroscore test), pre- and postinjury up to 4 weeks. The mice were killed after 1 or 4 weeks, and cortical lesion volume, as well as hippocampal and thalamic cell loss, was evaluated. Hippocampal staining with doublecortin antibody was used to evaluate neurogenesis after the insult. Brain-injured XPA(-/-) mice exhibited delayed recovery from impairment in neurological motor function, as well as pronounced cognitive dysfunction in a spatial learning task (Morris water maze), compared with injured XPA(+/+) mice (p recovery after TBI, although they do not support the notion that this DNA repair deficiency results in increased cell or tissue death in the posttraumatic brain.

  3. Impaired Cytogenetic Damage Repair and Cell Cycle Regulation in Response to Ionizing Radiation in Human Fibroblast Cells with Individual Knock-down of 25 Genes

    Science.gov (United States)

    Zhang, Ye; Rohde, Larry; Emami, Kamal; Hammond, Dianne; Casey, Rachael; Mehta, Satish; Jeevarajan, Antony; Pierson, Duane; Wu, Honglu

    2008-01-01

    Changes of gene expression profile are one of the most important biological responses in living cells after ionizing radiation (IR) exposure. Although some studies have demonstrated that genes with upregulated expression induced by IR may play important roles in DNA damage sensing, cell cycle checkpoint and chromosomal repair, the relationship between the regulation of gene expression by IR and its impact on cytogenetic responses to ionizing radiation has not been systematically studied. In our present study, the expression of 25 genes selected based on their transcriptional changes in response to IR or from their known DNA repair roles were individually knocked down by siRNA transfection in human fibroblast cells. Chromosome aberrations (CA) and micronuclei (MN) formation were measured as the cytogenetic endpoints. Our results showed that the yield of MN and/or CA formation were significantly increased by suppressed expression of 5 genes that included Ku70 in the DSB repair pathway; XPA in the NER pathway; RPA1 in the MMR pathway; RAD17 and RBBP8 in cell cycle control. Knocked-down expression of 4 genes including MRE11A, RAD51 in the DSB pathway, and SESN1 and SUMO1 showed significant inhibition of cell cycle progression, possibly because of severe impairment of DNA damage repair. Furthermore, loss of XPA, p21 and MLH1 expression resulted in both enhanced cell cycle progression and significantly higher yield of cytogenetic damage, indicating the involvement of these gene products in both cell cycle control and DNA damage repair. Of these 11 genes that affected the cytogenetic response, 9 were up-regulated in the cells exposed to gamma radiation, suggesting that genes transcriptionally modulated by IR were critical to regulating the biological consequences after IR. Failure to express these IR-responsive genes, such as by gene mutation, could seriously change the outcome of the post IR scenario and lead to carcinogenesis.

  4. Zebrafish with mutations in mismatch repair genes develop neurofibromas and other tumors.

    NARCIS (Netherlands)

    Feitsma, H.; Kuiper, R.V.; Korving, J.; Nijman, I.J.; Cuppen, E.

    2008-01-01

    Defective mismatch repair (MMR) in humans causes hereditary nonpolyposis colorectal cancer. This genetic predisposition to colon cancer is linked to heterozygous familial mutations, and loss-of-heterozygosity is necessary for tumor development. In contrast, the rare cases with biallelic MMR

  5. Transient expression of a plasmid gene, a tool to study DNA repair in human cells: defect of DNA repair in Cockayne syndrome; one thymine cyclobutane dimer is sufficient to block transcription.

    Science.gov (United States)

    Klocker, H; Schneider, R; Burtscher, H J; Auer, B; Hirsch-Kauffmann, M; Schweiger, M

    1986-01-01

    Transfected recombinant DNA with regulatory elements such as eukaryotic promoter and termination sites is transiently expressed in human fibroblast cells. Utilizing an expression vector containing the simian virus 40 (SV 40) early control region followed by the E. coli chloramphenicol acetyltransferase (CAT) gene, we investigated the ability of normal, Xeroderma pigmentosum and Cockayne Syndrome cells to repair UV lesions in transfected DNA. Fibroblasts from Xeroderma pigmentosum patients which cannot excise pyrimidine cyclobutane dimers were unable to restore expression of UV irradiated CAT gene. An UV dose inducing one thymine cyclobutane dimer in the transcribed strand of the CAT gene blocked its transcription in these repair deficient cells. Normal cell were able to repair the lesions in transfected DNA during an incubation period of about 40 h and in this way could overcome the UV block. In several fibroblast cell lines from patients suffering from Cockayne Syndrome expression of UV damaged CAT gene was restored significantly less than in normal fibroblasts, indicating that Cockayne Syndrome is associated with a UV repair defect.

  6. Effect of exposure to 2.45 GHz microwave on DNA repair genes transcription in cultured cells

    Energy Technology Data Exchange (ETDEWEB)

    Perrin, A.; Bachelet, C. [Molecular and Cellular Biophysics Unit of the Health Service Research Center for Defense (CRSSA), 38 - Grenoble (France); Fournier, C.; Peinnequin, A. [Radiobiology and Inflamation Unit of the Health Service Research Center for Defense (CRSSA), 38 - Grenoble (France); Leveque, P.; Collin, A. [Research Institut on Microwave and Optical Communications (IRCOM), CNRS UMR 6615, 87 - Limoges (France)

    2006-07-01

    The aim of the study was to investigate, in vitro, the effect of 2.45 GHz continuous (C.W.) and pulsed (P.W.) electromagnetic field exposure combined with a known mutagen on the induction of enzymes implicated in the DNA repair pathway. Microwaves do not create bonds breaks within molecules and there is no clear hypothesis for a possible mechanism supporting a biological action. Nevertheless, an indirect influence of microwaves during an intermediary step of the complex sequence of events involved in mutagenesis cannot yet be excluded. Highly sensitive real-time R.T.q.P.C.R. was used to monitor transcriptional variations of DNA repair genes. The experiments were carried out using the monocyte human cell line T.H.P.1 with the genotoxic compound 4- nitro-quinoline-N-oxide (4-N.Q.O.). The carrier frequency was 2.45 GHz C.W. and P.W. (1 khz repetition time, 10 % duty cycle) with the same power density corresponding to an average specific absorption rate (S.A.R.) value of 0.19 W/kg in the biological samples. Non exposed (sham) and exposed (P.W. and C.W.) cell culture plates were incubated simultaneously in three identical incubators in the presence of 4-N.Q.O., under shaking, at 37 Celsius degrees. Specially designed incubators were integrated in three identical anechoic chambers equipped with waveguide antennas. Care was taken to increase the reproducibility of the experiments and to avoid false positive or misinterpretation of the results. The presence or the absence of the electromagnetic field was the only difference between the sham and exposed assays. The different exposure conditions were applied alternatively in the three anechoic chambers in order to avoid cage effects. The temperature inside the cell plates was measured with an optic fiber probe (Luxtron). Numerical dosimetry was calculated using the Finite Difference Time Domain method. A time-scaled form of the heat transfer equation allowed to calculate the temperature distribution inside the petri dishes

  7. Antioxidative Dietary Compounds Modulate Gene Expression Associated with Apoptosis, DNA Repair, Inhibition of Cell Proliferation and Migration

    Directory of Open Access Journals (Sweden)

    Likui Wang

    2014-09-01

    Full Text Available Many dietary compounds are known to have health benefits owing to their antioxidative and anti-inflammatory properties. To determine the molecular mechanism of these food-derived compounds, we analyzed their effect on various genes related to cell apoptosis, DNA damage and repair, oxidation and inflammation using in vitro cell culture assays. This review further tests the hypothesis proposed previously that downstream products of COX-2 (cyclooxygenase-2 called electrophilic oxo-derivatives induce antioxidant responsive elements (ARE, which leads to cell proliferation under antioxidative conditions. Our findings support this hypothesis and show that cell proliferation was inhibited when COX-2 was down-regulated by polyphenols and polysaccharides. Flattened macrophage morphology was also observed following the induction of cytokine production by polysaccharides extracted from viili, a traditional Nordic fermented dairy product. Coix lacryma-jobi (coix polysaccharides were found to reduce mitochondrial membrane potential and induce caspase-3- and 9-mediated apoptosis. In contrast, polyphenols from blueberries were involved in the ultraviolet-activated p53/Gadd45/MDM2 DNA repair system by restoring the cell membrane potential. Inhibition of hypoxia-inducible factor-1 by saponin extracts of ginsenoside (Ginsen and Gynostemma and inhibition of S100A4 by coix polysaccharides inhibited cancer cell migration and invasion. These observations suggest that antioxidants and changes in cell membrane potential are the major driving forces that transfer signals through the cell membrane into the cytosol and nucleus, triggering gene expression, changes in cell proliferation and the induction of apoptosis or DNA repair.

  8. Antioxidative Dietary Compounds Modulate Gene Expression Associated with Apoptosis, DNA Repair, Inhibition of Cell Proliferation and Migration

    Science.gov (United States)

    Wang, Likui; Gao, Shijuan; Jiang, Wei; Luo, Cheng; Xu, Maonian; Bohlin, Lars; Rosendahl, Markus; Huang, Wenlin

    2014-01-01

    Many dietary compounds are known to have health benefits owing to their antioxidative and anti-inflammatory properties. To determine the molecular mechanism of these food-derived compounds, we analyzed their effect on various genes related to cell apoptosis, DNA damage and repair, oxidation and inflammation using in vitro cell culture assays. This review further tests the hypothesis proposed previously that downstream products of COX-2 (cyclooxygenase-2) called electrophilic oxo-derivatives induce antioxidant responsive elements (ARE), which leads to cell proliferation under antioxidative conditions. Our findings support this hypothesis and show that cell proliferation was inhibited when COX-2 was down-regulated by polyphenols and polysaccharides. Flattened macrophage morphology was also observed following the induction of cytokine production by polysaccharides extracted from viili, a traditional Nordic fermented dairy product. Coix lacryma-jobi (coix) polysaccharides were found to reduce mitochondrial membrane potential and induce caspase-3- and 9-mediated apoptosis. In contrast, polyphenols from blueberries were involved in the ultraviolet-activated p53/Gadd45/MDM2 DNA repair system by restoring the cell membrane potential. Inhibition of hypoxia-inducible factor-1 by saponin extracts of ginsenoside (Ginsen) and Gynostemma and inhibition of S100A4 by coix polysaccharides inhibited cancer cell migration and invasion. These observations suggest that antioxidants and changes in cell membrane potential are the major driving forces that transfer signals through the cell membrane into the cytosol and nucleus, triggering gene expression, changes in cell proliferation and the induction of apoptosis or DNA repair. PMID:25226533

  9. SNPs in DNA repair or oxidative stress genes and late subcutaneous fibrosis in patients following single shot partial breast irradiation

    Directory of Open Access Journals (Sweden)

    Falvo Elisabetta

    2012-01-01

    Full Text Available Abstract Background The aim of this study was to evaluate the potential association between single nucleotide polymorphisms related response to radiotherapy injury, such as genes related to DNA repair or enzymes involved in anti-oxidative activities. The paper aims to identify marker genes able to predict an increased risk of late toxicity studying our group of patients who underwent a Single Shot 3D-CRT PBI (SSPBI after BCS (breast conserving surgery. Methods A total of 57 breast cancer patients who underwent SSPBI were genotyped for SNPs (single nucleotide polymorphisms in XRCC1, XRCC3, GST and RAD51 by Pyrosequencing technology. Univariate analysis (ORs and 95% CI was performed to correlate SNPs with the risk of developing ≥ G2 fibrosis or fat necrosis. Results A higher significant risk of developing ≥ G2 fibrosis or fat necrosis in patients with: polymorphic variant GSTP1 (Ile105Val (OR = 2.9; 95%CI, 0.88-10.14, p = 0.047. Conclusions The presence of some SNPs involved in DNA repair or response to oxidative stress seem to be able to predict late toxicity. Trial Registration ClinicalTrials.gov: NCT01316328

  10. SNPs in DNA repair or oxidative stress genes and late subcutaneous fibrosis in patients following single shot partial breast irradiation.

    Science.gov (United States)

    Falvo, Elisabetta; Strigari, Lidia; Citro, Gennaro; Giordano, Carolina; Boboc, Genoveva; Fabretti, Fabiana; Bruzzaniti, Vicente; Bellesi, Luca; Muti, Paola; Blandino, Giovanni; Pinnarò, Paola

    2012-01-24

    The aim of this study was to evaluate the potential association between single nucleotide polymorphisms related response to radiotherapy injury, such as genes related to DNA repair or enzymes involved in anti-oxidative activities. The paper aims to identify marker genes able to predict an increased risk of late toxicity studying our group of patients who underwent a Single Shot 3D-CRT PBI (SSPBI) after BCS (breast conserving surgery). A total of 57 breast cancer patients who underwent SSPBI were genotyped for SNPs (single nucleotide polymorphisms) in XRCC1, XRCC3, GST and RAD51 by Pyrosequencing technology. Univariate analysis (ORs and 95% CI) was performed to correlate SNPs with the risk of developing ≥ G2 fibrosis or fat necrosis. A higher significant risk of developing ≥ G2 fibrosis or fat necrosis in patients with: polymorphic variant GSTP1 (Ile105Val) (OR = 2.9; 95%CI, 0.88-10.14, p = 0.047). The presence of some SNPs involved in DNA repair or response to oxidative stress seem to be able to predict late toxicity. ClinicalTrials.gov: NCT01316328.

  11. Elevated Human Telomerase Reverse Transcriptase Gene Expression in Blood Cells Associated with Chronic Arsenic Exposure in Inner Mongolia, China

    Science.gov (United States)

    Mo, Jinyao; Xia, Yajuan; Ning, Zhixiong; Wade, Timothy J.; Mumford, Judy L.

    2009-01-01

    Background Arsenic exposure is associated with human cancer. Telomerase-containing human telomerase reverse transcriptase (hTERT) can extend telomeres of chromosomes, delay senescence, and promote cell proliferation leading to tumorigenesis. Objective The goal of this study was to investigate the effects of As on hTERT mRNA expression in humans and in vitro. Method A total of 324 Inner Mongolia residents who have been exposed to As via drinking water participated in this study. Water and toenail samples were collected and analyzed for As. Blood samples were quantified for hTERT mRNA expression using real-time polymerase chain reaction. The hTERT mRNA levels were linked to water and nail As concentrations and skin hyperkeratosis. Human epidermal keratinocytes were treated with arsenite to assess effects on cell viability and hTERT expression in vitro. Results hTERT mRNA expression levels were significantly associated with As concentrations of water (p insults by As and may also indicate that As may function as a tumor promoter in carcinogenesis in humans. PMID:19337508

  12. Arsenic Treatment Technology Demonstrations

    Science.gov (United States)

    EPA’s research for the new Arsenic Rule focused on the development and evaluation of innovative methods and cost-effective technologies for improving the assessment and control of arsenic contamination.

  13. Fact Sheet on Arsenic

    Science.gov (United States)

    Arsenic is a naturally occurring element that is found in combination with either inorganic or organic substances to form many different compounds. Inorganic arsenic compounds are found in soils, sediments, and groundwater.

  14. Arsenic: natural and anthropogenic

    National Research Council Canada - National Science Library

    Matschullat, Jörg; Deschamps, Eleonora

    2011-01-01

    .... Based on state-of-the-art investigations into the global arsenic cycle, the related human toxicology and available remediation technologies, it assesses arsenic in all the environmental compartments...

  15. Toxic Substances Portal- Arsenic

    Science.gov (United States)

    ... a naturally occurring element widely distributed in the earth's crust. In the environment, arsenic is combined with ... that inhaled or ingested arsenic can injure pregnant women or their unborn babies, although the studies are ...

  16. Cryptic exposure to arsenic.

    Science.gov (United States)

    Rossy, Kathleen M; Janusz, Christopher A; Schwartz, Robert A

    2005-01-01

    Arsenic is an odorless, colorless and tasteless element long linked with effects on the skin and viscera. Exposure to it may be cryptic. Although human intake can occur from four forms, elemental, inorganic (trivalent and pentavalent arsenic) and organic arsenic, the trivalent inorganic arsenicals constitute the major human hazard. Arsenic usually reaches the skin from occupational, therapeutic, or environmental exposure, although it still may be employed as a poison. Occupations involving new technologies are not exempt from arsenic exposure. Its acute and chronic effects are noteworthy. Treatment options exist for arsenic-induced pathology, but prevention of toxicity remains the main focus. Vitamin and mineral supplementation may play a role in the treatment of arsenic toxicity.

  17. Arsenic Alters ATP-Dependent Ca2+ Signaling in Human Airway Epithelial Cell Wound Response

    Science.gov (United States)

    Sherwood, Cara L.; Lantz, R. Clark; Burgess, Jefferey L.; Boitano, Scott

    2011-01-01

    Arsenic is a natural metalloid toxicant that is associated with occupational inhalation injury and contaminates drinking water worldwide. Both inhalation of arsenic and consumption of arsenic-tainted water are correlated with malignant and nonmalignant lung diseases. Despite strong links between arsenic and respiratory illness, underlying cell responses to arsenic remain unclear. We hypothesized that arsenic may elicit some of its detrimental effects on the airway through limitation of innate immune function and, specifically, through alteration of paracrine ATP (purinergic) Ca2+ signaling in the airway epithelium. We examined the effects of acute (24 h) exposure with environmentally relevant levels of arsenic (i.e., arsenic reduces purinergic Ca2+ signaling in a dose-dependent manner and results in a reshaping of the Ca2+ signaling response to localized wounds. We next examined arsenic effects on two purinergic receptor types: the metabotropic P2Y and ionotropic P2X receptors. Arsenic inhibited both P2Y- and P2X-mediated Ca2+ signaling responses to ATP. Both inhaled and ingested arsenic can rapidly reach the airway epithelium where purinergic signaling is essential in innate immune functions (e.g., ciliary beat, salt and water transport, bactericide production, and wound repair). Arsenic-induced compromise of such airway defense mechanisms may be an underlying contributor to chronic lung disease. PMID:21357385

  18. Arsenic Poisoning in Bangladesh

    National Research Council Canada - National Science Library

    Huda , Naz Hasan; Uddin , Riaz

    2011-01-01

    ... in drinking water. (2) People in Bangladesh become terror-stricken when they come to know that underground water in parts of the country is strained by deadly arsenic. The permissible level of arsenic in water is 50 ppb (Parts per billion) according to experts. But according to the Bangladesh Atomic Energy Commission, the level of arsenic is between 150 and 200...

  19. Characterization of the linkage disequilibrium structure and identification of tagging-SNPs in five DNA repair genes

    Directory of Open Access Journals (Sweden)

    Camp Nicola J

    2005-08-01

    Full Text Available Abstract Background Characterization of the linkage disequilibrium (LD structure of candidate genes is the basis for an effective association study of complex diseases such as cancer. In this study, we report the LD and haplotype architecture and tagging-single nucleotide polymorphisms (tSNPs for five DNA repair genes: ATM, MRE11A, XRCC4, NBS1 and RAD50. Methods The genes ATM, MRE11A, and XRCC4 were characterized using a panel of 94 unrelated female subjects (47 breast cancer cases, 47 controls obtained from high-risk breast cancer families. A similar LD structure and tSNP analysis was performed for NBS1 and RAD50, using publicly available genotyping data. We studied a total of 61 SNPs at an average marker density of 10 kb. Using a matrix decomposition algorithm, based on principal component analysis, we captured >90% of the intragenetic variation for each gene. Results Our results revealed that three of the five genes did not conform to a haplotype block structure (MRE11A, RAD50 and XRCC4. Instead, the data fit a more flexible LD group paradigm, where SNPs in high LD are not required to be contiguous. Traditional haplotype blocks assume recombination is the only dynamic at work. For ATM, MRE11A and XRCC4 we repeated the analysis in cases and controls separately to determine whether LD structure was consistent across breast cancer cases and controls. No substantial difference in LD structures was found. Conclusion This study suggests that appropriate SNP selection for an association study involving candidate genes should allow for both mutation and recombination, which shape the population-level genomic structure. Furthermore, LD structure characterization in either breast cancer cases or controls appears to be sufficient for future cancer studies utilizing these genes.

  20. Pathological complete response after cisplatin neoadjuvant therapy is associated with the downregulation of DNA repair genes in BRCA1-associated triple-negative breast cancers.

    Science.gov (United States)

    Domagala, Pawel; Hybiak, Jolanta; Rys, Janusz; Byrski, Tomasz; Cybulski, Cezary; Lubinski, Jan

    2016-10-18

    Pathologic complete response (pCR) after neoadjuvant chemotherapy is considered a suitable surrogate marker of treatment efficacy in patients with triple-negative breast cancers (TNBCs). However, the molecular mechanisms underlying pCR as a result of such treatment remain obscure. Using real-time PCR arrays we compared the expression levels of 120 genes involved in the main mechanisms of DNA repair in 43 pretreatment biopsies of BRCA1-associated TNBCs exhibiting pCR and no pathological complete response (non-pCR) after neoadjuvant chemotherapy with cisplatin. Altogether, 25 genes were significantly differentially expressed between tumors exhibiting pCR and non-pCR, and these genes were downregulated in the pCR group compared to the non-pCR group. A difference in expression level greater than 1.5-fold was detected for nine genes: MGMT, ERCC4, FANCB, UBA1, XRCC5, XPA, XPC, PARP3, and RPA1. The non-homologous end joining and nucleotide excision repair pathways of DNA repair showed the most significant relevance. Expression profile of DNA repair genes associated with pCR was different in the node-positive (20 genes with fold change >1.5) and node-negative (only 3 genes) subgroups. Although BRCA1 germline mutations are the principal defects in BRCA1-associated TNBC, our results indicate that the additional downregulation of other genes engaged in major pathways of DNA repair may play a decisive role in the pathological response of these tumors to cisplatin neoadjuvant chemotherapy. The results suggest that patients with node-positive BRCA1-associated TNBCs that do not exhibit pCR after cisplatin neoadjuvant chemotherapy may be candidates for subsequent therapy with PARP inhibitors, whereas UBA1 may be a potential therapeutic target in node-negative subgroup.

  1. Dependence of colorectal cancer risk on the parent-of-origin of mutations in DNA mismatch repair genes.

    Science.gov (United States)

    van Vliet, Christine M; Dowty, James G; van Vliet, Jane L; Smith, Letitia; Mead, Leeanne J; Macrae, Finlay A; St John, D James B; Giles, Graham G; Southey, Melissa C; Jenkins, Mark A; Velan, Gary M; Hopper, John L

    2011-02-01

    Genetic diseases associated with dynamic mutations in microsatellite DNA often display parent-of-origin effects (POEs) in which the risk of disease depends on the sex of the parent from whom the disease allele was inherited. Carriers of germline mutations in mismatch repair (MMR) genes have high risks of colorectal carcinoma (CRC). We investigated whether these risks depend on the parent-of-origin of the mutation. We studied 422 subjects, including 89 MMR gene mutation carriers, from 17 population-based families who were each recruited via a CRC case diagnosed before age 45 years and found to carry a MMR gene mutation. The POE hazard ratio (HR(POE)), defined to be the CRC incidence for carriers with maternally derived mutations divided by the corresponding paternal incidence, was estimated using a novel application of modified segregation analysis. HR(POE) (95% confidence interval) was estimated to be 3.2 (1.1-9.8) for males (P = 0.03) and 0.8 (0.2-2.8) for females (P = 0.5) and the corresponding cumulative risks to age 80 years were 88% (54%-100%) for male carriers with maternally derived mutations and 38-48% for all other carriers. If confirmed by larger studies, these results will have important implications for the etiology of CRC and for the clinical management of MMR gene mutation carriers. © 2011 Wiley-Liss, Inc.

  2. Polysaccharides of Aloe vera induce MMP-3 and TIMP-2 gene expression during the skin wound repair of rat.

    Science.gov (United States)

    Tabandeh, Mohammad Reza; Oryan, Ahmad; Mohammadalipour, Adel

    2014-04-01

    Polysaccharides are the main macromolecules of Aloe vera gel but no data about their effect on extracellular matrix (ECM) elements are available. Here, mannose rich Aloe vera polysaccharides (AVP) with molecular weight between 50 and 250 kDa were isolated and characterized. Open cutaneous wounds on the back of 45 rats (control and treated) were daily treated with 25mg (n=15) and 50 mg (n=15) AVP for 30 days. The levels of MMP-3 and TIMP-2 gene expression were analyzed using real time PCR. The levels of n-acetyl glucosamine (NAGA), n-acetyl galactosamine (NAGLA) and collagen contents were also measured using standard biochemical methods. Faster wound closure was observed at day 15 post wounding in AVP treated animals in comparison with untreated group. At day 10 post wounding, AVP inhibited MMP-3 gene expression, while afterwards MMP-3 gene expression was upregulated. AVP enhanced TIMP-2 gene expression, collagen, NAGLA and NAGA synthesis in relation to untreated wounds. Our results suggest that AVP has positive effects on the regulation of ECM factor synthesis, which open up new perspectives for the wound repair activity of Aloe vera polysaccharide at molecular level. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. The GH/IGF-1 axis in a critical period early in life determines cellular DNA repair capacity by altering transcriptional regulation of DNA repair-related genes: implications for the developmental origins of cancer.

    Science.gov (United States)

    Podlutsky, Andrej; Valcarcel-Ares, Marta Noa; Yancey, Krysta; Podlutskaya, Viktorija; Nagykaldi, Eszter; Gautam, Tripti; Miller, Richard A; Sonntag, William E; Csiszar, Anna; Ungvari, Zoltan

    2017-04-01

    Experimental, clinical, and epidemiological findings support the concept of developmental origins of health and disease (DOHAD), suggesting that early-life hormonal influences during a sensitive period around adolescence have a powerful impact on cancer morbidity later in life. The endocrine changes that occur during puberty are highly conserved across mammalian species and include dramatic increases in circulating GH and IGF-1 levels. Importantly, patients with developmental IGF-1 deficiency due to GH insensitivity (Laron syndrome) do not develop cancer during aging. Rodents with developmental GH/IGF-1 deficiency also exhibit significantly decreased cancer incidence at old age, marked resistance to chemically induced carcinogenesis, and cellular resistance to genotoxic stressors. Early-life treatment of GH/IGF-1-deficient mice and rats with GH reverses the cancer resistance phenotype; however, the underlying molecular mechanisms remain elusive. The present study was designed to test the hypothesis that developmental GH/IGF-1 status impacts cellular DNA repair mechanisms. To achieve that goal, we assessed repair of γ-irradiation-induced DNA damage (single-cell gel electrophoresis/comet assay) and basal and post-irradiation expression of DNA repair-related genes (qPCR) in primary fibroblasts derived from control rats, Lewis dwarf rats (a model of developmental GH/IGF-1 deficiency), and GH-replete dwarf rats (GH administered beginning at 5 weeks of age, for 30 days). We found that developmental GH/IGF-1 deficiency resulted in persisting increases in cellular DNA repair capacity and upregulation of several DNA repair-related genes (e.g., Gadd45a, Bbc3). Peripubertal GH treatment reversed the radiation resistance phenotype. Fibroblasts of GH/IGF-1-deficient Snell dwarf mice also exhibited improved DNA repair capacity, showing that the persisting influence of peripubertal GH/IGF-1 status is not species-dependent. Collectively, GH/IGF-1 levels during a critical period

  4. Inhibition factors of arsenic trioxide therapeutic effects in patients with acute promyelocytic leukemia.

    Science.gov (United States)

    Sui, Meijuan; Zhang, Zhuo; Zhou, Jin

    2014-01-01

    To summarize limitations involved in arsenic trioxide therapeutic effects in acute promyelocytic leukemia, because current studies show that some individuals of acute promyelocytic leukemia have relatively poor outcomes during treatment with arsenic trioxide. Most relevant articles were included in the PubMed database between 2000 and 2013 with the keywords "acute promyelocytic leukemia," "arsenic trioxide," "thiol" or "methylation." In addition, a few older articles were also reviewed. Data and articles related to arsenic trioxide effect in acute promyelocytic leukemia treatment were selected and reviewed. We developed an overview of limitations associated with arsenic trioxide therapeutic effect. This review focuses on the researches about the arsenic trioxide therapeutic effect in acute promyelocytic leukemia and summarizes three mainly limitations which can influence the arsenic trioxide therapeutic effect to different degrees. First, with the combination of arsenic and glutathione the therapeutic effect and cytotoxicity decrease when glutathione concentration increases; second, arsenic methylation, stable arsenic methylation products weaken the apoptosis effect of arsenic trioxide in leukemia cells; third, gene mutations affect the sensitivity of tumor cells to arsenic trioxide and increase the resistance of leukemia cells to arsenic trioxide. The chief limitations are listed in the review. If we can exclude all of them, we can obtain a better therapeutic effect of arsenic trioxide in patients with acute promyelocytic leukemia.

  5. Essential role of cell cycle regulatory genes p21 and p27 expression in inhibition of breast cancer cells by arsenic trioxide.

    Science.gov (United States)

    Wang, Xi; Gao, Ping; Long, Min; Lin, Fang; Wei, Jun-Xia; Ren, Ji-Hong; Yan, Lin; He, Ting; Han, Yuan; Zhang, Hui-Zhong

    2011-12-01

    Arsenic trioxide (As2O3), a component of traditional Chinese medicine, has been used successfully for the treatment of acute promyelocytic leukemia (APL), and As2O3 is of potential therapeutic value for the treatment of other promyelocytic malignancies and some solid tumors including breast cancer. However, the precise molecular mechanisms through which As2O3 induces cell cycle arrest and apoptosis in solid tumors have not been clearly understood. The goal of our study is to gain insight into the general biological processes and molecular functions that are altered by As2O3 treatment in MCF-7 breast cancer cells and to identify the key signaling processes that are involved in the regulation of these physiological effects. In the present study, MCF-7 cells were treated with 5 μM As2O3, and the differential gene expression was then analyzed by DNA microarray. The results showed that As2O3 treatment changed the expression level of several genes that involved in cell cycle regulation, signal transduction, and apoptosis. Notably, As2O3 treatment increased the mRNA and protein levels of the cell cycle inhibitory proteins, p21 and p27. Interestingly, knocking down p21 or p27 individually did not alter As2O3-induced apoptosis and cell cycle arrest; however, the simultaneous down-regulation of both p21 and p27 resulted in attenuating of G1, G2/M arrest and reduction in apoptosis, thus indicating that p21 and p27 as the primary molecular targets of As2O3 against breast cancer. Overall, our results provide new insights into As2O3-related signaling activities, which may facilitate the development of As2O3-based anticancer strategies and/or combination therapies against solid tumors.

  6. DNA repair gene ERCC2, XPC, XRCC1, XRCC3 polymorphisms and associations with bladder cancer risk in a French cohort.

    Science.gov (United States)

    Fontana, Luc; Bosviel, Rémy; Delort, Laetitia; Guy, Laurent; Chalabi, Nasséra; Kwiatkowski, Fabrice; Satih, Samir; Rabiau, Nadège; Boiteux, Jean-Paul; Chamoux, Alain; Bignon, Yves-Jean; Bernard-Gallon, Dominique J

    2008-01-01

    In polygenic diseases, association studies look for genetic variation such as polymorphisms in low penetrance genes, i.e. genes in interaction with environmental factors. DNA repair systems that protect the genome from deleterious endogenous and exogenous damage have been shown to significantly reduce activity. In particular, enzymes of the nucleotide excision repair pathway are suspected to be implicated in cancer. In this study bladder cancer which is viewed as a polygenic disease was investigated. The functional polymorphisms of four DNA repair genes, excision repair cross-complementing group 2 (ERCC2), Xeroderma Pigmentosum group C (XPC), and Xray repair cross-complementing groups 1 and 3 (XRCC1 and XRCC3) were analyzed. The studied population included 51 bladder cancer cases and 45 controls. The genotyping of six SNP (single nucleotide polymorphism) was carried out on these populations with the MGB (Minor Groove Binder) probe technique which uses allelic discrimination with the Taqman method. The Gln allele of the XPC 939 polymorphism was found to be associated with an increase in bladder cancer risk.

  7. GLI3 Links Environmental Arsenic Exposure and Human Fetal Growth

    Directory of Open Access Journals (Sweden)

    Emily F. Winterbottom

    2015-06-01

    Full Text Available Although considerable evidence suggests that in utero arsenic exposure affects children's health, these data are mainly from areas of the world where groundwater arsenic levels far exceed the World Health Organization limit of 10 μg/L. We, and others, have found that more common levels of in utero arsenic exposure may also impact children's health. However, the underlying molecular mechanisms are poorly understood. To address this issue, we analyzed the expression of key developmental genes in fetal placenta in a birth cohort of women using unregulated water supplies in a US region with elevated groundwater arsenic. We identified several genes whose expression associated with maternal arsenic exposure in a fetal sex-specific manner. In particular, expression of the HEDGEHOG pathway component, GLI3, in female placentae was both negatively associated with arsenic exposure and positively associated with infant birth weight. This suggests that modulation of GLI3 in the fetal placenta, and perhaps in other fetal tissues, contributes to arsenic's detrimental effects on fetal growth. We showed previously that arsenic-exposed NIH3T3 cells have reduced GLI3 repressor protein. Together, these studies identify GLI3 as a key signaling node that is affected by arsenic, mediating a subset of its effects on developmental signaling and fetal health.

  8. Many amino acid substitution variants identified in DNA repair genes during human population screenings are predicted to impact protein function

    Energy Technology Data Exchange (ETDEWEB)

    Xi, T; Jones, I M; Mohrenweiser, H W

    2003-11-03

    Over 520 different amino acid substitution variants have been previously identified in the systematic screening of 91 human DNA repair genes for sequence variation. Two algorithms were employed to predict the impact of these amino acid substitutions on protein activity. Sorting Intolerant From Tolerant (SIFT) classified 226 of 508 variants (44%) as ''Intolerant''. Polymorphism Phenotyping (PolyPhen) classed 165 of 489 amino acid substitutions (34%) as ''Probably or Possibly Damaging''. Another 9-15% of the variants were classed as ''Potentially Intolerant or Damaging''. The results from the two algorithms are highly associated, with concordance in predicted impact observed for {approx}62% of the variants. Twenty one to thirty one percent of the variant proteins are predicted to exhibit reduced activity by both algorithms. These variants occur at slightly lower individual allele frequency than do the variants classified as ''Tolerant'' or ''Benign''. Both algorithms correctly predicted the impact of 26 functionally characterized amino acid substitutions in the APE1 protein on biochemical activity, with one exception. It is concluded that a substantial fraction of the missense variants observed in the general human population are functionally relevant. These variants are expected to be the molecular genetic and biochemical basis for the associations of reduced DNA repair capacity phenotypes with elevated cancer risk.

  9. Arsenic: homicidal intoxication

    Energy Technology Data Exchange (ETDEWEB)

    Massey, E.W.; Wold, D.; Heyman, A.

    1984-07-01

    Arsenic-induced deaths have been known to occur from accidental poisoning, as a result of medical therapy, and from intentional poisonings in homicide and suicide. Twenty-eight arsenic deaths in North Carolina from 1972 to 1982 included 14 homicides and seven suicides. In addition, 56 hospitalized victims of arsenic poisoning were identified at Duke Medical Center from 1970 to 1980. Four case histories of arsenic poisoning in North Carolina are presented and clinical manifestations are discussed. In view of the continued widespread use of arsenic in industry and agriculture, and its ubiquity in the environment, arsenic poisoning will continue to occur. A need for knowledge of its toxicity and of the clinical manifestations of acute and chronic arsenic poisoning will also continue.

  10. Inactivation of the DNA repair genes mutS, mutL or the anti-recombination gene mutS2 leads to activation of vitamin B1 biosynthesis genes.

    Directory of Open Access Journals (Sweden)

    Kenji Fukui

    Full Text Available Oxidative stress generates harmful reactive oxygen species (ROS that attack biomolecules including DNA. In living cells, there are several mechanisms for detoxifying ROS and repairing oxidatively-damaged DNA. In this study, transcriptomic analyses clarified that disruption of DNA repair genes mutS and mutL, or the anti-recombination gene mutS2, in Thermus thermophilus HB8, induces the biosynthesis pathway for vitamin B(1, which can serve as an ROS scavenger. In addition, disruption of mutS, mutL, or mutS2 resulted in an increased rate of oxidative stress-induced mutagenesis. Co-immunoprecipitation and pull-down experiments revealed previously-unknown interactions of MutS2 with MutS and MutL, indicating that these proteins cooperatively participate in the repair of oxidatively damaged DNA. These results suggested that bacterial cells sense the accumulation of oxidative DNA damage or absence of DNA repair activity, and signal the information to the transcriptional regulation machinery for an ROS-detoxifying system.

  11. Comparative Genomics Analysis of a New Exiguobacterium Strain from Salar de Huasco Reveals a Repertoire of Stress-Related Genes and Arsenic Resistance.

    Science.gov (United States)

    Castro-Severyn, Juan; Remonsellez, Francisco; Valenzuela, Sandro L; Salinas, Cesar; Fortt, Jonathan; Aguilar, Pablo; Pardo-Esté, Coral; Dorador, Cristina; Quatrini, Raquel; Molina, Franck; Aguayo, Daniel; Castro-Nallar, Eduardo; Saavedra, Claudia P

    2017-01-01

    The Atacama Desert hosts diverse ecosystems including salt flats and shallow Andean lakes. Several heavy metals are found in the Atacama Desert, and microorganisms growing in this environment show varying levels of resistance/tolerance to copper, tellurium, and arsenic, among others. Herein, we report the genome sequence and comparative genomic analysis of a new Exiguobacterium strain, sp. SH31, isolated from an altiplanic shallow athalassohaline lake. Exiguobacterium sp. SH31 belongs to the phylogenetic Group II and its closest relative is Exiguobacterium sp. S17, isolated from the Argentinian Altiplano (95% average nucleotide identity). Strain SH31 encodes a wide repertoire of proteins required for cadmium, copper, mercury, tellurium, chromium, and arsenic resistance. Of the 34 Exiguobacterium genomes that were inspected, only isolates SH31 and S17 encode the arsenic efflux pump Acr3. Strain SH31 was able to grow in up to 10 mM arsenite and 100 mM arsenate, indicating that it is arsenic resistant. Further, expression of the ars operon and acr3 was strongly induced in response to both toxics, suggesting that the arsenic efflux pump Acr3 mediates arsenic resistance in Exiguobacterium sp. SH31.

  12. Inactivation of RAD52 and HDF1 DNA repair genes leads to ...

    Indian Academy of Sciences (India)

    Silvia Mercado-Sáenz

    2017-04-18

    Apr 18, 2017 ... respiration. As a consequence, low glucose leads to increase both replicative and chronological life span (Breitenbach et al. 2012). It has been reported that glycolytic/fermentative genes are upregulated in Sch9Δ, Ras2Δ and Tor1Δ mutants, while mitochondrial genes are down-regulated. In this way, it has.

  13. 8-Methoxypsoralen DNA interstrand cross-linking of the ribosomal RNA genes in Tetrahymena thermophila. Distribution, repair and effect on rRNA synthesis

    DEFF Research Database (Denmark)

    Fengquin, X; Nielsen, Henrik; Zhen, W

    1993-01-01

    The distribution and repair of 8-methoxypsoralen-DNA interstrand cross-links in the ribosomal RNA genes (rDNA) in Tetrahymena thermophila have been studied in vivo by Southern blot analysis. It is found that the cross-links at a density of ... between three domains (terminal spacer, transcribed region and central spacer) as defined by restriction enzyme analysis (BamHI and ClaI). It is furthermore shown that a dosage resulting in approximately one cross-link per rDNA molecule (21 kbp, two genes) is sufficient to block RNA synthesis. Finally......, it is shown that the cross-links in the rDNA molecules are repaired at equal rate in all three domains within 24 h and that RNA synthesis is partly restored during this repair period. The majority of the cells also go through one to two cell divisions in this period but do not survive....

  14. Radioprotective effects of Bmi-1 involve epigenetic silencing of oxidase genes and enhanced DNA repair in normal human keratinocytes.

    Science.gov (United States)

    Dong, Qinghua; Oh, Ju-Eun; Chen, Wei; Kim, Roy; Kim, Reuben H; Shin, Ki-Hyuk; McBride, William H; Park, No-Hee; Kang, Mo K

    2011-06-01

    Normal human keratinocytes (NHKs) undergo premature senescence following exposure to ionizing radiation (IR). This study investigates the effect of Bmi-1, a polycomb group protein, on radiation-induced senescence response. When exposed to IR, NHK transduced with Bmi-1 (NHK/Bmi-1) showed reduced senescent phenotype and enhanced proliferation compared with control cells (NHK/B0). To investigate the underlying mechanism, we determined the production of reactive oxygen species (ROS), expression of ROS-generating enzymes, and DNA repair activities in cells. ROS level was increased upon irradiation but notably reduced by Bmi-1 transduction. Irradiation led to strong induction of oxidase genes, e.g., Lpo (lactoperoxidase), p22-phox, p47-phox, and Gp91, in NHK/B0 but their expression was almost completely silenced in NHK/Bmi-1. Induction of oxidase genes upon irradiation was linked with loss of trimethylated histone 3 at lysine 27 (H3K27Me3), but NHK/Bmi-1 expressed a higher level of H3K27Me3 compared with NHK/B0. Bmi-1 transduction suppressed IR-associated induction of jumanji domain containing 3 while enhancing the expression of EZH2, thereby preventing the loss of H3K27Me3 in the irradiated cells. Furthermore, NHK/Bmi-1 demonstrated increased repair of IR-induced DNA damage compared with NHK/B0. These results indicate that Bmi-1 elicits radioprotective effects on NHK by mitigating the genotoxicity of IR through epigenetic mechanisms.

  15. Identification of mismatch repair gene mutations in young patients with colorectal cancer and in patients with multiple tumours associated with hereditary non-polyposis colorectal cancer.

    NARCIS (Netherlands)

    Niessen, R.C.; Berends, M.J.; Wu, Y.; Sijmons, R.H.; Hollema, H.; Ligtenberg, M.J.L.; Walle, H.E. de; Vries, E.G.F. de; Karrenbeld, A.; Buys, C.H.C.M.; Zee, A.G. van der; Hofstra, R.M.; Kleibeuker, J.H.

    2006-01-01

    BACKGROUND: Patients with early-onset colorectal cancer (CRC) or those with multiple tumours associated with hereditary non-polyposis colorectal cancer (HNPCC) raise suspicion of the presence of germline DNA mismatch repair (MMR) gene mutations. AIM: To analyse the value of family history,

  16. Identification of mismatch repair gene mutations in young patients with colorectal cancer and in patients with multiple tumours associated with hereditary non-polyposis colorectal cancer

    NARCIS (Netherlands)

    Niessen, R C; Berends, M J W; Wu, Y; Sijmons, R H; Hollema, H; Ligtenberg, M J L; de Walle, H E K; de Vries, E G E; Karrenbeld, A; Buys, C H C M; van der Zee, A G J; Hofstra, R M W; Kleibeuker, J H

    2006-01-01

    Background: Patients with early-onset colorectal cancer (CRC) or those with multiple tumours associated with hereditary non-polyposis colorectal cancer (HNPCC) raise suspicion of the presence of germline DNA mismatch repair (MMR) gene mutations. Aim: To analyse the value of family history,

  17. Transcriptomics and methylomics of CD4-positive T cells in arsenic-exposed women.

    Science.gov (United States)

    Engström, Karin; Wojdacz, Tomasz K; Marabita, Francesco; Ewels, Philip; Käller, Max; Vezzi, Francesco; Prezza, Nicola; Gruselius, Joel; Vahter, Marie; Broberg, Karin

    2017-05-01

    Arsenic, a carcinogen with immunotoxic effects, is a common contaminant of drinking water and certain food worldwide. We hypothesized that chronic arsenic exposure alters gene expression, potentially by altering DNA methylation of genes encoding central components of the immune system. We therefore analyzed the transcriptomes (by RNA sequencing) and methylomes (by target-enrichment next-generation sequencing) of primary CD4-positive T cells from matched groups of four women each in the Argentinean Andes, with fivefold differences in urinary arsenic concentrations (median concentrations of urinary arsenic in the lower- and high-arsenic groups: 65 and 276 μg/l, respectively). Arsenic exposure was associated with genome-wide alterations of gene expression; principal component analysis indicated that the exposure explained 53% of the variance in gene expression among the top variable genes and 19% of 28,351 genes were differentially expressed (false discovery rate arsenic group. Arsenic exposure was associated with genome-wide DNA methylation; the high-arsenic group had 3% points higher genome-wide full methylation (>80% methylation) than the lower-arsenic group. Differentially methylated regions that were hyper-methylated in the high-arsenic group showed enrichment for immune-related gene ontologies that constitute the basic functions of CD4-positive T cells, such as isotype switching and lymphocyte activation and differentiation. In conclusion, chronic arsenic exposure from drinking water was related to changes in the transcriptome and methylome of CD4-positive T cells, both genome wide and in specific genes, supporting the hypothesis that arsenic causes immunotoxicity by interfering with gene expression and regulation.

  18. Genetic variations in DNA repair genes, radiosensitivity to cancer and susceptibility to acute tissue reactions in radiotherapy-treated cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Chistiakov, Dimitry A. (Dept. of Pathology, Univ. of Pittsburgh, Pittsburgh (US)); Voronova, Natalia V. (Dept. of Molecular Diagnostics, National Research Center GosNIIgenetika, Moscow (RU)); Chistiakov, Pavel A. (Dept. of Radiology, Cancer Research Center, Moscow (RU))

    2008-06-15

    Ionizing radiation is a well established carcinogen for human cells. At low doses, radiation exposure mainly results in generation of double strand breaks (DSBs). Radiation-related DSBs could be directly linked to the formation of chromosomal rearrangements as has been proven for radiation-induced thyroid tumors. Repair of DSBs presumably involves two main pathways, non-homologous end joining (NHEJ) and homologous recombination (HR). A number of known inherited syndromes, such as ataxia telangiectasia, ataxia-telangiectasia like-disorder, radiosensitive severe combined immunodeficiency, Nijmegen breakage syndrome, and LIG4 deficiency are associated with increased radiosensitivity and/or cancer risk. Many of them are caused by mutations in DNA repair genes. Recent studies also suggest that variations in the DNA repair capacity in the general population may influence cancer susceptibility. In this paper, we summarize the current status of DNA repair proteins as potential targets for radiation-induced cancer risk. We will focus on genetic alterations in genes involved in HR- and NHEJ-mediated repair of DSBs, which could influence predisposition to radiation-related cancer and thereby explain interindividual differences in radiosensitivity or radioresistance in a general population

  19. Environmental Source of Arsenic Exposure

    OpenAIRE

    Chung, Jin-Yong; Yu, Seung-Do; Hong, Young-Seoub

    2014-01-01

    Arsenic is a ubiquitous, naturally occurring metalloid that may be a significant risk factor for cancer after exposure to contaminated drinking water, cigarettes, foods, industry, occupational environment, and air. Among the various routes of arsenic exposure, drinking water is the largest source of arsenic poisoning worldwide. Arsenic exposure from ingested foods usually comes from food crops grown in arsenic-contaminated soil and/or irrigated with arsenic-contaminated water. According to a ...

  20. Genetic variants in DNA double-strand break repair genes and risk of salivary gland carcinoma: a case-control study.

    Directory of Open Access Journals (Sweden)

    Li Xu

    Full Text Available DNA double strand break (DSB repair is the primary defense mechanism against ionizing radiation-induced DNA damage. Ionizing radiation is the only established risk factor for salivary gland carcinoma (SGC. We hypothesized that genetic variants in DSB repair genes contribute to individual variation in susceptibility to SGC. To test this hypothesis, we conducted a case-control study in which we analyzed 415 single nucleotide polymorphisms (SNPs in 45 DSB repair genes in 352 SGC cases and 598 controls. Multivariate logistic regression analysis was performed to calculate odds ratios (ORs and 95% confidence intervals (CIs. Rs3748522 in RAD52 and rs13180356 in XRCC4 were significantly associated with SGC after Bonferroni adjustment; ORs (95% CIs for the variant alleles of these SNPs were 1.71 (1.40-2.09, P = 1.70 × 10(-7 and 0.58 (0.45-0.74, P = 2.00 × 10(-5 respectively. The genetic effects were modulated by histological subtype. The association of RAD52-rs3748522 with SGC was strongest for mucoepidermoid carcinoma (OR = 2.21, 95% CI: 1.55-3.15, P = 1.25 × 10(-5, n = 74, and the association of XRCC4-rs13180356 with SGC was strongest for adenoid cystic carcinoma (OR = 0.60, 95% CI: 0.42-0.87, P = 6.91 × 10(-3, n = 123. Gene-level association analysis revealed one gene, PRKDC, with a marginally significant association with SGC risk in non-Hispanic whites. To our knowledge, this study is the first to comprehensively evaluate the genetic effect of DSB repair genes on SGC risk. Our results indicate that genetic variants in the DSB repair pathways contribute to inter-individual differences in susceptibility to SGC and show that the impact of genetic variants differs by histological subtype. Independent studies are warranted to confirm these findings.

  1. Gene Expression Changes in Human Lung Cells Exposed to Arsenic, Chromium, Nickel or Vanadium Indicate the First Steps in Cancer

    OpenAIRE

    Clancy, Hailey A.; Sun, Hong; Passantino, Lisa; Kluz, Thomas; Muñoz, Alexandra; Zavadil, Jiri; Costa, Max

    2012-01-01

    The complex process of carcinogenesis begins with transformation of a single cell to favor aberrant traits such as loss of contact inhibition and unregulated proliferation – features found in every cancer. Despite cancer’s widespread prevalence, the early events that initiate cancer remain elusive, and without knowledge of these events cancer prevention is difficult. Here we show that exposure to As, Cr, Ni, or Vanadium (V) promotes changes in gene expression that occur in conjunction with ab...

  2. Association between methylation in mismatch repair genes, V600E BRAF mutation and microsatellite instability in colorectal cancer patients.

    Science.gov (United States)

    Rasuck, Carla G; Leite, Sinara M O; Komatsuzaki, Flavia; Ferreira, Alessandro C S; Oliveira, Vanessa C; Gomes, Karina B

    2012-03-01

    Colorectal cancer (CRC) corresponds to the third most prevalent type of cancer. Its origins can either be sporadic or inherited, being Lynch syndrome the most common form of hereditary CRC. The activation of BRAF oncogene, inactivation of mismatch repair genes by methylation of CpG islands, and microsatellite instability (MSI) have been reported to be involved in CRC development. The goal of the study was to characterize CRC tumors using clinical and molecular criteria through association and cluster analysis. Amsterdam II and Bethesda guidelines and molecular variables were analyzed in 77 patients from Brazil. The replication error (RER) status, based in microsatellite instability, showed association with metachronous tumor, MLH1 gene methylation and inverse association with left-sided and synchronous tumors. The PMS2 gene was considered the best predictor for differentiating levels of methylation and the mononucleotide were considered the best markers to evaluate RER status. The cluster 1 was characterized of individuals over 60 years of age, female, right-sided tumor, high microsatellite instability, and metachronous or synchronous tumors. The individuals in cluster 2 were younger than 45 years of age, male and showed left sided or rectum tumors, and microsatellite stability. Even though it was not observed a significant association, a higher number of individuals with family history of cancer and tumors without promoter methylation were found in cluster 2. The V600E mutation did not show association with clinical or molecular characteristics. Evaluation of MSI and methylation of MLH1 and PMS2 genes should be considered in order to assist with clinical diagnosis.

  3. Recent developments with the human repair genes ERCC2, ERCC4, and XRCC1

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, L.H.; Caldecott, K.W.; Brookman, K.W.; Weber, C.A.; Salazar, E.S.; Takayama, K. [Lawrence Livermore National Lab., CA (United States); Fornace, A.J. [National Cancer Inst., Bethesda, MD (United States). Lab. of Molecular Pharmacology

    1992-11-06

    ERCC2 was first identified as a gene on human chromosome 19 that complemented the UV sensitivity of CHO UV5 cells in somatic cell hybrids. Subsequent studies localized ERCC2 to the same chromosomal region (19q13.2--13.3) as the ERCC1 gene and showed that the two genes were less than 250 kb apart. Cloning of ERCC2 was accomplished by transfection of genomic DNA into UV5 cells and rescue of the gene from a secondary transformant. Recovery of the gene was aided by the presence of repetitive sequences that were detected on Southern blots with a probe for Alu-family repeats. ERCC2, which is 19 kb in size, quantitatively corrected the UV sensitivity and incision defect in UV5 cells upon transfection. An ERCC2 CDNA clone was recovered from the pcD2 expression library. Although this clone was truncated at the 5 in. end, it conferred transient, but not stable, correction to UV5 cells upon transfection. Based on genomic sequence, this clone was extended by oligonucleotide addition to obtain minigene constructs in which the complete open reading frame (ORF) was present. Translation of the ERCC2 ORF gives an amino acid sequence that has 72% similarity with the S. cerevisiae RAD3 protein, which encodes a DNA helicase.

  4. Cloning of a human homolog of the yeast nucleotide excision repair gene MMS19 and interaction with transcription repair factor TFIIH via the XPB and XPD helicases

    NARCIS (Netherlands)

    T. Seroz; G.S. Winkler (Sebastiaan); J. Auriol; R.A. Verhage; W. Vermeulen (Wim); B. Smit (Bep); J. Brouwer (Jaap); G. Weeda (Geert); J.H.J. Hoeijmakers (Jan); A.P.M. Eker (André); J-M. Egly (Jean-Marc)

    2000-01-01

    textabstractNucleotide excision repair (NER) removes UV-induced photoproducts and numerous other DNA lesions in a highly conserved 'cut-and-paste' reaction that involves approximately 25 core components. In addition, several other proteins have been identified which are dispensable for NER in vitro

  5. Strain differences in arsenic-induced oxidative lesion via arsenic biomethylation between C57BL/6J and 129X1/SvJ mice

    Science.gov (United States)

    Wu, Ruirui; Wu, Xiafang; Wang, Huihui; Fang, Xin; Li, Yongfang; Gao, Lanyue; Sun, Guifan; Pi, Jingbo; Xu, Yuanyuan

    2017-03-01

    Arsenic is a common environmental and occupational toxicant with dramatic species differences in its susceptibility and metabolism. Mouse strain variability may provide a better understanding of the arsenic pathological profile but is largely unknown. Here we investigated oxidative lesion induced by acute arsenic exposure in the two frequently used mouse strains C57BL/6J and 129X1/SvJ in classical gene targeting technique. A dose of 5 mg/kg body weight arsenic led to a significant alteration of blood glutathione towards oxidized redox potential and increased hepatic malondialdehyde content in C57BL/6J mice, but not in 129X1/SvJ mice. Hepatic antioxidant enzymes were induced by arsenic in transcription in both strains and many were higher in C57BL/6J than 129X1/SvJ mice. Arsenic profiles in the liver, blood and urine and transcription of genes encoding enzymes involved in arsenic biomethylation all indicate a higher arsenic methylation capacity, which contributes to a faster hepatic arsenic excretion, in 129X1/SvJ mice than C57BL/6J mice. Taken together, C57BL/6J mice are more susceptible to oxidative hepatic injury compared with 129X1/SvJ mice after acute arsenic exposure, which is closely associated with arsenic methylation pattern of the two strains.

  6. DISTRIBUTION OF DNA DAMAGE REPAIR GENE POLYMORPHISM hOGG1, XRCC1 and p53 AMONG SICKLE CELL DISEASE PATIENTS IN INDIA

    Directory of Open Access Journals (Sweden)

    Sudhansu Sekhar Nishank

    2015-07-01

    Full Text Available Background– Defect in DNA damage repair genes due to oxidative stress predispose the humans to malignancies. There are many cases of association of malignancies with sickle cell disease patients (SCD throughout the world, the molecular cause of which has never been investigated. DNA damage repair genes such as  hOGG1, XRCC1 and p53 play significant role in repair of DNA damage during oxidative stress but the distribution and clinical effect of these genes are not known till date in SCD patients who are associated with oxidative stress related clinical complications.         Objective – The aim of the study was to characterize the distribution and clinical effect of DNA damage gene polymorphisms p53 (codon 72 Arg> Pro, hOGG1 (codon 326 Ser>Cyst and XRCC1 (codons 194 Arg>Trp, codon 280 Arg> His, codon 399 Arg> Gln among SCD patients of  central India.  Methods- A case control study of  250 SCD patients and 250 normal individuals were investigated by PCR-RFLP techniques.      Result- The prevalence of mutant alleles of hOGG1 gene, XRCC1 codon 280 Arg>His  were found to be significantly high among SCD patients as compared to controls. However, SCD patients did not show clinical association with any of these DNA repair gene polymorphisms.   Conclusion- This indicates that hOGG1, p53  and XRCC1 gene polymorphisms  may not have any clinical impact among SCD patients in India.

  7. Cobalt-induced genotoxicity in male zebrafish (Danio rerio), with implications for reproduction and expression of DNA repair genes

    Energy Technology Data Exchange (ETDEWEB)

    Reinardy, Helena C.; Syrett, James R. [School of Biomedical and Biological Sciences, University of Plymouth (United Kingdom); Jeffree, Ross A. [Faculty of Science, University of Technology, Sydney, PO Box 123, Broadway, NSW 2007 (Australia); Henry, Theodore B., E-mail: ted.henry@plymouth.ac.uk [School of Biomedical and Biological Sciences, University of Plymouth (United Kingdom); Center for Environmental Biotechnology, University of Tennessee, Knoxville, TN 37996 (United States); Department of Forestry, Wildlife and Fisheries, University of Tennessee, Knoxville, TN 37996. USA (United States); Jha, Awadhesh N. [School of Biomedical and Biological Sciences, The University of Plymouth (United Kingdom)

    2013-01-15

    Although cobalt (Co) is an environmental contaminant of surface waters in both radioactive (e.g. {sup 60}Co) and non-radioactive forms, there is relatively little information about Co toxicity in fishes. The objective of this study was to investigate acute and chronic toxicity of Co in zebrafish, with emphasis on male genotoxicity and implications for reproductive success. The lethal concentration for 50% mortality (LC{sub 50}) in larval zebrafish exposed (96 h) to 0-50 mg l{sup -1} Co was 35.3 {+-} 1.1 (95% C.I.) mg l{sup -1} Co. Adult zebrafish were exposed (13 d) to sub-lethal (0-25 mg l{sup -1}) Co and allowed to spawn every 4 d and embryos were collected. After 12-d exposure, fertilisation rate was reduced (6% total eggs fertilised, 25 mg l{sup -1}) and embryo survival to hatching decreased (60% fertilised eggs survived, 25 mg l{sup -1}). A concentration-dependent increase in DNA strand breaks was detected in sperm from males exposed (13 d) to Co, and DNA damage in sperm returned to control levels after males recovered for 6 d in clean water. Induction of DNA repair genes (rad51, xrcc5, and xrcc6) in testes was complex and not directly related to Co concentration, although there was significant induction in fish exposed to 15 and 25 mg l{sup -1} Co relative to controls. Induction of 4.0 {+-} 0.9, 2.5 {+-} 0.7, and 3.1 {+-} 0.7-fold change (mean {+-} S.E.M. for rad51, xrcc5, and xrcc6, respectively) was observed in testes at the highest Co concentration (25 mg l{sup -1}). Expression of these genes was not altered in offspring (larvae) spawned after 12-d exposure. Chronic exposure to Co resulted in DNA damage in sperm, induction of DNA repair genes in testes, and indications of reduced reproductive success.

  8. Hereditary truncating mutations of DNA repair and other genes in BRCA1/BRCA2/PALB2-negatively tested breast cancer patients.

    Science.gov (United States)

    Lhota, F; Zemankova, P; Kleiblova, P; Soukupova, J; Vocka, M; Stranecky, V; Janatova, M; Hartmannova, H; Hodanova, K; Kmoch, S; Kleibl, Z

    2016-10-01

    Hereditary breast cancer comprises a minor but clinically meaningful breast cancer (BC) subgroup. Mutations in the major BC-susceptibility genes are important prognostic and predictive markers; however, their carriers represent only 25% of high-risk BC patients. To further characterize variants influencing BC risk, we performed SOLiD sequencing of 581 genes in 325 BC patients (negatively tested in previous BRCA1/BRCA2/PALB2 analyses). In 105 (32%) patients, we identified and confirmed 127 truncating variants (89 unique; nonsense, frameshift indels, and splice site), 19 patients harbored more than one truncation. Forty-six (36 unique) truncating variants in 25 DNA repair genes were found in 41 (12%) patients, including 16 variants in the Fanconi anemia (FA) genes. The most frequent variant in FA genes was c.1096_1099dupATTA in FANCL that also show a borderline association with increased BC risk in subsequent analysis of enlarged groups of BC patients and controls. Another 81 (53 unique) truncating variants were identified in 48 non-DNA repair genes in 74 patients (23%) including 16 patients carrying variants in genes coding proteins of estrogen metabolism/signaling. Our results highlight the importance of mutations in the FA genes' family, and indicate that estrogen metabolism genes may reveal a novel candidate genetic component for BC susceptibility. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Methylation and protein expression of DNA repair genes: association with chemotherapy exposure and survival in sporadic ovarian and peritoneal carcinomas

    Directory of Open Access Journals (Sweden)

    Walsh Tom

    2009-07-01

    Full Text Available Abstract Background DNA repair genes critically regulate the cellular response to chemotherapy and epigenetic regulation of these genes may be influenced by chemotherapy exposure. Restoration of BRCA1 and BRCA2 mediates resistance to platinum chemotherapy in recurrent BRCA1 and BRCA2 mutated hereditary ovarian carcinomas. We evaluated BRCA1, BRCA2, and MLH1 protein expression in 115 sporadic primary ovarian carcinomas, of which 31 had paired recurrent neoplasms collected after chemotherapy. Additionally, we assessed whether promoter methylation of BRCA1, MLH1 or FANCF influenced response to chemotherapy or explained alterations in protein expression after chemotherapy exposure. Results Of 115 primary sporadic ovarian carcinomas, 39 (34% had low BRCA1 protein and 49 (42% had low BRCA2 expression. BRCA1 and BRCA2 protein expression were highly concordant (p Conclusion Low BRCA1 expression in primary sporadic ovarian carcinoma is associated with prolonged survival. Recurrent ovarian carcinomas commonly have increased BRCA1 and/or BRCA2 protein expression post chemotherapy exposure which could mediate resistance to platinum based therapies. However, alterations in expression of these proteins after chemotherapy are not commonly mediated by promoter methylation, and other regulatory mechanisms are likely to contribute to these alterations.

  10. Homologous Recombination DNA Repair Genes Play a Critical Role in Reprogramming to a Pluripotent State

    Directory of Open Access Journals (Sweden)

    Federico González

    2013-03-01

    Full Text Available Induced pluripotent stem cells (iPSCs hold great promise for personalized regenerative medicine. However, recent studies show that iPSC lines carry genetic abnormalities, suggesting that reprogramming may be mutagenic. Here, we show that the ectopic expression of reprogramming factors increases the level of phosphorylated histone H2AX, one of the earliest cellular responses to DNA double-strand breaks (DSBs. Additional mechanistic studies uncover a direct role of the homologous recombination (HR pathway, a pathway essential for error-free repair of DNA DSBs, in reprogramming. This role is independent of the use of integrative or nonintegrative methods in introducing reprogramming factors, despite the latter being considered a safer approach that circumvents genetic modifications. Finally, deletion of the tumor suppressor p53 rescues the reprogramming phenotype in HR-deficient cells primarily through the restoration of reprogramming-dependent defects in cell proliferation and apoptosis. These mechanistic insights have important implications for the design of safer approaches to creating iPSCs.

  11. A unique DNA repair and recombination gene (recN) sequence for ...

    Indian Academy of Sciences (India)

    2013-04-23

    Apr 23, 2013 ... Ribosomal gene sequences are a popular choice for identification of bacterial species and, often, for making phylogenetic interpretations. Although very popular, the sequences of 16S rDNA and 16-23S intergenic sequences often fail to differentiate closely related species of bacteria. The availability of ...

  12. A unique DNA repair and recombination gene (recN) sequence for ...

    Indian Academy of Sciences (India)

    Ribosomal gene sequences are a popular choice for identification of bacterial species and, often, for making phylogenetic interpretations. Although very popular, the sequences of 16S rDNA and 16-23S intergenic sequences often fail to differentiate closely related species of bacteria. The availability of complete genome ...

  13. Expression of stress-related genes in tomato plants exposed to arsenic and chromium in nutrient solution.

    Science.gov (United States)

    Goupil, Pascale; Souguir, Dalila; Ferjani, Ezzedine; Faure, Olivier; Hitmi, Adnane; Ledoigt, Gérard

    2009-09-01

    The molecular responses of hydroponically cultivated tomato plants to As(V) or Cr(VI) were assessed by transcript accumulation analysis of genes coding for products potentially involved in heavy metal tolerance. A quantitative real-time PCR experiment was performed with Hsp90-1, MT2- and GR1-like protein genes using RNA isolated from tomato roots or shoots treated for 24h with As(V) or Cr(VI) at concentrations ranging from 80 to 640 microM. Both transient metallic treatments induced Hsp90-1 transcript accumulation in tomato plants. MT2- and GR1-like transcripts accumulated in tomato roots treated with As(V) but were only slightly affected by Cr(VI) treatment. Tomatoes showed phenotypic symptoms to heavy metal toxicity when plants were exposed to Cr(VI) but not As(V). Plant lethality was observed at 1280 microM Cr(VI), indicating that tomatoes were more tolerant to As than Cr stress under the experimental conditions used here.

  14. DNA damage repair genes controlling human papillomavirus (HPV episome levels under conditions of stability and extreme instability.

    Directory of Open Access Journals (Sweden)

    Terri G Edwards

    Full Text Available DNA damage response (DDR genes and pathways controlling the stability of HPV episomal DNA are reported here. We set out to understand the mechanism by which a DNA-binding, N-methylpyrrole-imidazole hairpin polyamide (PA25 acts to cause the dramatic loss of HPV DNA from cells. Southern blots revealed that PA25 alters HPV episomes within 5 hours of treatment. Gene expression arrays identified numerous DDR genes that were specifically altered in HPV16 episome-containing cells (W12E by PA25, but not in HPV-negative (C33A cells or in cells with integrated HPV16 (SiHa. A siRNA screen of 240 DDR genes was then conducted to identify enhancers and repressors of PA25 activity. Serendipitously, the screen also identified many novel genes, such as TDP1 and TDP2, regulating normal HPV episome stability. MRN and 9-1-1 complexes emerged as important for PA25-mediated episome destruction and were selected for follow-up studies. Mre11, along with other homologous recombination and dsDNA break repair genes, was among the highly significant PA25 repressors. The Mre11 inhibitor Mirin was found to sensitize HPV episomes to PA25 resulting in a ∼5-fold reduction of the PA25 IC50. A novel assay that couples end-labeling of DNA to Q-PCR showed that PA25 causes strand breaks within HPV DNA, and that Mirin greatly enhances this activity. The 9-1-1 complex member Rad9, a representative PA25 enhancer, was transiently phosphorylated in response to PA25 treatment suggesting that it has a role in detecting and signaling episome damage by PA25 to the cell. These results establish that DNA-targeted compounds enter cells and specifically target the HPV episome. This action leads to the activation of numerous DDR pathways and the massive elimination of episomal DNA from cells. Our findings demonstrate that viral episomes can be targeted for elimination from cells by minor groove binding agents, and implicate DDR pathways as important mediators of this process.

  15. DNA damage repair genes controlling human papillomavirus (HPV) episome levels under conditions of stability and extreme instability.

    Science.gov (United States)

    Edwards, Terri G; Vidmar, Thomas J; Koeller, Kevin; Bashkin, James K; Fisher, Chris

    2013-01-01

    DNA damage response (DDR) genes and pathways controlling the stability of HPV episomal DNA are reported here. We set out to understand the mechanism by which a DNA-binding, N-methylpyrrole-imidazole hairpin polyamide (PA25) acts to cause the dramatic loss of HPV DNA from cells. Southern blots revealed that PA25 alters HPV episomes within 5 hours of treatment. Gene expression arrays identified numerous DDR genes that were specifically altered in HPV16 episome-containing cells (W12E) by PA25, but not in HPV-negative (C33A) cells or in cells with integrated HPV16 (SiHa). A siRNA screen of 240 DDR genes was then conducted to identify enhancers and repressors of PA25 activity. Serendipitously, the screen also identified many novel genes, such as TDP1 and TDP2, regulating normal HPV episome stability. MRN and 9-1-1 complexes emerged as important for PA25-mediated episome destruction and were selected for follow-up studies. Mre11, along with other homologous recombination and dsDNA break repair genes, was among the highly significant PA25 repressors. The Mre11 inhibitor Mirin was found to sensitize HPV episomes to PA25 resulting in a ∼5-fold reduction of the PA25 IC50. A novel assay that couples end-labeling of DNA to Q-PCR showed that PA25 causes strand breaks within HPV DNA, and that Mirin greatly enhances this activity. The 9-1-1 complex member Rad9, a representative PA25 enhancer, was transiently phosphorylated in response to PA25 treatment suggesting that it has a role in detecting and signaling episome damage by PA25 to the cell. These results establish that DNA-targeted compounds enter cells and specifically target the HPV episome. This action leads to the activation of numerous DDR pathways and the massive elimination of episomal DNA from cells. Our findings demonstrate that viral episomes can be targeted for elimination from cells by minor groove binding agents, and implicate DDR pathways as important mediators of this process.

  16. Prevalence of Germline Mutations in Genes Engaged in DNA Damage Repair by Homologous Recombination in Patients with Triple-Negative and Hereditary Non-Triple-Negative Breast Cancers.

    Directory of Open Access Journals (Sweden)

    Pawel Domagala

    Full Text Available This study sought to assess the prevalence of common germline mutations in several genes engaged in the repair of DNA double-strand break by homologous recombination in patients with triple-negative breast cancers and hereditary non-triple-negative breast cancers. Tumors deficient in this type of DNA damage repair are known to be especially sensitive to DNA cross-linking agents (e.g., platinum drugs and to poly(ADP-ribose polymerase (PARP inhibitors.Genetic testing was performed for 36 common germline mutations in genes engaged in the repair of DNA by homologous recombination, i.e., BRCA1, BRCA2, CHEK2, NBN, ATM, PALB2, BARD1, and RAD51D, in 202 consecutive patients with triple-negative breast cancers and hereditary non-triple-negative breast cancers.Thirty five (22.2% of 158 patients in the triple-negative group carried mutations in genes involved in DNA repair by homologous recombination, while 10 (22.7% of the 44 patients in the hereditary non-triple-negative group carried such mutations. Mutations in BRCA1 were most frequent in patients with triple-negative breast cancer (18.4%, and mutations in CHEK2 were most frequent in patients with hereditary non-triple-negative breast cancers (15.9%. In addition, in the triple-negative group, mutations in CHEK2, NBN, and ATM (3.8% combined were found, while mutations in BRCA1, NBN, and PALB2 (6.8% combined were identified in the hereditary non-triple-negative group.Identifying mutations in genes engaged in DNA damage repair by homologous recombination other than BRCA1/2 can substantially increase the proportion of patients with triple-negative breast cancer and hereditary non-triple-negative breast cancer who may be eligible for therapy using PARP inhibitors and platinum drugs.

  17. Prevalence of Germline Mutations in Genes Engaged in DNA Damage Repair by Homologous Recombination in Patients with Triple-Negative and Hereditary Non-Triple-Negative Breast Cancers.

    Science.gov (United States)

    Domagala, Pawel; Jakubowska, Anna; Jaworska-Bieniek, Katarzyna; Kaczmarek, Katarzyna; Durda, Katarzyna; Kurlapska, Agnieszka; Cybulski, Cezary; Lubinski, Jan

    2015-01-01

    This study sought to assess the prevalence of common germline mutations in several genes engaged in the repair of DNA double-strand break by homologous recombination in patients with triple-negative breast cancers and hereditary non-triple-negative breast cancers. Tumors deficient in this type of DNA damage repair are known to be especially sensitive to DNA cross-linking agents (e.g., platinum drugs) and to poly(ADP-ribose) polymerase (PARP) inhibitors. Genetic testing was performed for 36 common germline mutations in genes engaged in the repair of DNA by homologous recombination, i.e., BRCA1, BRCA2, CHEK2, NBN, ATM, PALB2, BARD1, and RAD51D, in 202 consecutive patients with triple-negative breast cancers and hereditary non-triple-negative breast cancers. Thirty five (22.2%) of 158 patients in the triple-negative group carried mutations in genes involved in DNA repair by homologous recombination, while 10 (22.7%) of the 44 patients in the hereditary non-triple-negative group carried such mutations. Mutations in BRCA1 were most frequent in patients with triple-negative breast cancer (18.4%), and mutations in CHEK2 were most frequent in patients with hereditary non-triple-negative breast cancers (15.9%). In addition, in the triple-negative group, mutations in CHEK2, NBN, and ATM (3.8% combined) were found, while mutations in BRCA1, NBN, and PALB2 (6.8% combined) were identified in the hereditary non-triple-negative group. Identifying mutations in genes engaged in DNA damage repair by homologous recombination other than BRCA1/2 can substantially increase the proportion of patients with triple-negative breast cancer and hereditary non-triple-negative breast cancer who may be eligible for therapy using PARP inhibitors and platinum drugs.

  18. Arsenic[III] and heavy metal ions induce intrachromosomal homologous recombination in the hprt gene of V79 Chinese hamster cells.

    Science.gov (United States)

    Helleday, T; Nilsson, R; Jenssen, D

    2000-01-01

    In the present study the carcinogenic metal ions Cd[II], Co[II], Cr[VI], Ni[II], and Pb[II], as well as As[III], were examined for their ability to induce intrachromosomal homologous and nonhomologous recombination in the hprt gene of two V79 Chinese hamster cell lines, SPD8 and Sp5, respectively. With the exception of Pb[II], all of these ions enhanced homologous recombination, the order of potency being Cr>Cd>As>Co>Ni. In contrast, Cr[VI] was the only ion to enhance recombination of the nonhomologous type. In order to obtain additional information on the mechanism of recombination in the SPD8 cell line, individual clones exhibiting metal-induced recombination were isolated, and the sequence of their hprt gene determined. These findings confirmed that all recombinogenic events in this cell line were of the homologous type, involving predominantly a chromatid exchange mechanism. The mechanisms underlying the recombination induced by these ions are discussed in relationship to their genotoxicity, as well as to DNA repair and replication. Induced recombination may constitute a novel mechanism for induction of neoplastic disease. Copyright 2000 Wiley-Liss, Inc.

  19. DNA repair in human fibroblasts, as reflected by host-cell reactivation of a transfected UV-irradiated luciferase gene, is not related to donor age

    Energy Technology Data Exchange (ETDEWEB)

    Merkle, Thomas J.; O' Brien, Katherine; Brooks, Philip J.; Tarone, Robert E.; Robbins, Jay H

    2004-10-04

    The effect of donor age on the ability of mammalian cells to repair ultraviolet (UV)-induced DNA damage has been studied using several approaches, most recently via assays that measure the host-cell reactivation (HCR) of UV-irradiated reporter gene-containing plasmid vectors following their transfection into cells. Plasmid HCR assays indirectly quantify a cell line's ability to perform nucleotide excision repair (NER) by measuring the enzyme activity of the repaired reporter gene, e.g., chloramphenical acetyltransferase (cat) or luciferase (luc), and are useful in studies investigating whether increasing age may be a risk factor for the deficient repair of potentially cancer-causing, sunlight-induced, DNA lesions in skin cells. In our study, we quantified the DNA repair ability of cultured, nontransformed, human skin fibroblast lines through their HCR of a transfected UV-C-irradiated plasmid containing luc. HCR was measured at various times after transfection in five lines from normal donors of ages 21-96 years, and from one donor who had xeroderma pigmentosum (XP). The normal lines displayed increasing HCR at successive post-transfection time points and showed no significant correlation between HCR and donor age. The XP-A line, known to be markedly deficient in NER of UV-induced DNA damage, showed minimal evidence of HCR compared to the normal lines. To further assess potential variation in HCR with donor age, fibroblast lines from five old donors, ages 84-94 years, were compared with lines from five young donors, ages 17-26 years. While significant differences in HCR were found between some lines, no significant difference was found between the young and old age groups (P=0.44). Our study provides no indication that the higher incidence of skin cancer observed with increasing age is due to an age-related decrease in the ability to repair UV-induced DNA damage.

  20. Participation of different genes in the ruptures repair of double chain in Escherichia coli stumps exposed to gamma radiation; Participacion de diferentes genes en la reparacion de rupturas de doble cadena en cepas de Escherichia coli expuestas a radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Serment G, J. H.; Martinez M, E.; Alcantara D, D., E-mail: jorge.serment@inin.gob.mx [ININ, Departamento de Biologia, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2013-05-01

    All living organisms are naturally exposed to radiation from different sources. Ionizing radiation produces a plethora of lesions upon DNA that can be categorized as single and double strand breaks and base damage. Among them, unrepaired double strand breaks (Dbs) have the greatest biological significance, since they are responsible of cell death. In Escherichia coli this kind of lesions are repaired mostly by homologous recombination. In this work the participation of some recombination genes in the repair of Dbs is evaluated. Escherichia coli defective strains were exposed to gamma radiation and incubated for different periods in ideal conditions. Both micro electrophoresis and pulse field gel electrophoresis techniques were used to evaluate the kinetics of repair of such lesions, reflecting the importance of each defective gene in the process. (Author)

  1. Interactive effects of ultraviolet-B radiation and pesticide exposure on DNA photo-adduct accumulation and expression of DNA damage and repair genes in Xenopus laevis embryos.

    Science.gov (United States)

    Yu, Shuangying; Tang, Song; Mayer, Gregory D; Cobb, George P; Maul, Jonathan D

    2015-02-01

    Pesticide use and ultraviolet-B (UVB) radiation have both been suggested to adversely affect amphibians; however, little is known about their interactive effects. One potential adverse interaction could involve pesticide-induced dysregulation of DNA repair pathways, resulting in greater numbers of DNA photo-adducts from UVB exposure. In the present study, we investigated the interactive effects of UVB radiation and two common pesticides (endosulfan and α-cypermethrin) on induction of DNA photo-adducts and expression of DNA damage and repair related genes in African clawed frog (Xenopus laevis) embryos. We examined 13 genes that are, collectively, involved in stress defense, cell cycle arrest, nucleotide excision repair (NER), base excision repair, mismatch repair, DNA repair regulation, and apoptosis. We exposed X. laevis embryos to 0, 25, and 50 μg/L endosulfan or 0, 2.5, and 5.0 μg/L α-cypermethrin for 96 h, with environmentally relevant exposures of UVB radiation during the last 7 h of the 96 h exposure. We measured the amount of cyclobutane pyrimidine dimers (CPDs) and mRNA abundance of the 13 genes among treatments including control, pesticide only, UVB only, and UVB and pesticide co-exposures. Each of the co-exposure scenarios resulted in elevated CPD levels compared to UVB exposure alone, suggesting an inhibitory effect of endosulfan and α-cypermethrin on CPD repair. This is attributed to results indicating that α-cypermethrin and endosulfan reduced mRNA abundance of XPA and HR23B, respectively, to levels that may affect the initial recognition of DNA lesions. In contrast, both pesticides increased transcript abundance of CSA and MUTL. In addition, mRNA abundance of HSP70 and GADD45α were increased by endosulfan and mRNA abundance of XPG was increased by α-cypermethrin. XPC, HR23B, XPG, and GADD45α exhibited elevated mRNA concentrations whereas there was a reduction in MUTL transcript concentrations in UVB-alone treatments. It appeared that even

  2. Investigation of DNA repair-related SNPs underlying susceptibility to papillary thyroid carcinoma reveals MGMT as a novel candidate gene in Belarusian children exposed to radiation.

    Science.gov (United States)

    Lonjou, Christine; Damiola, Francesca; Moissonnier, Monika; Durand, Geoffroy; Malakhova, Irina; Masyakin, Vladimir; Le Calvez-Kelm, Florence; Cardis, Elisabeth; Byrnes, Graham; Kesminiene, Ausrele; Lesueur, Fabienne

    2017-05-12

    Genetic factors may influence an individual's sensitivity to ionising radiation and therefore modify his/her risk of developing papillary thyroid carcinoma (PTC). Previously, we reported that common single nucleotide polymorphisms (SNPs) within the DNA damage recognition gene ATM contribute to PTC risk in Belarusian children exposed to fallout from the Chernobyl power plant accident. Here we explored in the same population the contribution of a panel of DNA repair-related SNPs in genes acting downstream of ATM. The association of 141 SNPs located in 43 DNA repair genes was examined in 75 PTC cases and 254 controls from the Gomel region in Belarus. All subjects were younger than 15 years at the time of the Chernobyl accident. Conditional logistic regressions accounting for radiation dose were performed with PLINK using the additive allelic inheritance model, and a linkage disequilibrium (LD)-based Bonferroni correction was used for correction for multiple testing. The intronic SNP rs2296675 in MGMT was associated with an increased PTC risk [per minor allele odds ratio (OR) 2.54 95% CI 1.50, 4.30, P per allele = 0.0006, P corr.= 0.05], and gene-wide association testing highlighted a possible role for ERCC5 (P Gene = 0.01) and PCNA (P Gene = 0.05) in addition to MGMT (P Gene = 0.008). These findings indicate that several genes acting in distinct DNA repair mechanisms contribute to PTC risk. Further investigation is needed to decipher the functional properties of the methyltransferase encoded by MGMT and to understand how alteration of such functions may lead to the development of the most common type of thyroid cancer.

  3. [Acute arsenic poisoning].

    Science.gov (United States)

    Montelescaut, Etienne; Vermeersch, Véronique; Commandeur, Diane; Huynh, Sophie; Danguy des Deserts, Marc; Sapin, Jeanne; Ould-Ahmed, Mehdi; Drouillard, Isabelle

    2014-01-01

    Acute arsenic poisoning is a rare cause of suicide attempt. It causes a multiple organs failure caused by cardiogenic shock. We report the case of a patient admitted twelve hours after an ingestion of trioxide arsenic having survived thanks to a premature treatment.

  4. Global transcriptome profile reveals abundance of DNA damage response and repair genes in individuals from high level natural radiation areas of Kerala coast.

    Directory of Open Access Journals (Sweden)

    Vinay Jain

    Full Text Available The high level natural radiation areas (HLNRA of Kerala coast in south west India is unique for its wide variation in the background radiation dose (15.0 mGy/year] to find out differentially expressed genes and their biological significance in response to chronic low dose radiation exposure. Our results revealed a dose dependent increase in the number of differentially expressed genes with respect to different background dose levels. Gene ontology analysis revealed majority of these differentially expressed genes are involved in DNA damage response (DDR signaling, DNA repair, cell cycle arrest, apoptosis, histone/chromatin modification and immune response. In the present study, 64 background dose responsive genes have been identified as possible chronic low dose radiation signatures. Validation of 30 differentially expressed genes was carried out using fluorescent based universal probe library. Abundance of DDR and DNA repair genes along with pathways such as MAPK, p53 and JNK in higher background dose groups (> 5.0mGy/year indicated a possible threshold dose for DDR signaling and are plausible reason of observing in vivo radio-adaptive response and non-carcinogenesis in HLNRA population. To our knowledge, this is the first study on molecular effect of chronic low dose radiation exposure on human population from high background radiation areas at transcriptome level using high throughput approach. These findings have tremendous implications in understanding low dose radiation biology especially, the effect of low dose radiation exposure in humans.

  5. Ultrasound-induced hyperthermia for the spatio-temporal control of gene expression in bone repair

    Science.gov (United States)

    Wilson, Christopher; Padilla, Frédéric; Zhang, Man; Vilaboa, Nuria; Kripfgans, Oliver; Fowlkes, Brian; Franceschi, Renny

    2012-10-01

    Spatial and temporal control over the expression of growth/differentiation factors is of great interest for regeneration of bone, but technologies capable of providing tight and active control over gene expression remain elusive. We propose the use of focused ultrasound for the targeted activation of heat shock-sensitive expression systems in engineered bone. We report in vitro results with cells that express firefly luciferase (fLuc) under the control of a heat shock protein promoter. Cells were embedded in fibrin scaffolds and exposed to focused ultrasound, using a custom 3.3MHz transducer (focal length 4", f-number 1.33", focal dimension 1.2mm lateral FWHM) in CW mode for 2-20 minutes at intensities ISPTA=120-440 W/cm2. The kinetics of ultrasound-mediated activation of the cells was compared with that of strictly thermal activation. Bioluminescence imaging revealed fLuc expression in an area ≥2.5mm in diameter at the position of the ultrasound focus, and the diameter and intensity of the signal increased with the amplitude of the acoustic energy. We also found that ultrasound activated fLuc expression with substantially shorter exposures than thermal activation. Our results demonstrate the potential for focused ultrasound to selectively activate the expression of a gene of interest in an engineered tissue and suggest that focused ultrasound activates the heat shock pathway by a combination of thermal and non-thermal mechanisms.

  6. Glutathione Modulates Recominant Rat Arsenic (+3 Oxidation State) Methyltransferase-Catalyzed Formation of Trimethylarsine Oxide and Trimethylarsine

    Science.gov (United States)

    Humans and other species enzymatically convert inorganic arsenic (iAs) into methylated metabolites. Although the major metabolites are mono- and dimethylated arsenicals, trimethylated arsenicals have been detected in urine following exposure to iAs. The AS3MT gene encodes an ars...

  7. Histone Sprocket Arginine Residues Are Important for Gene Expression, DNA Repair, and Cell Viability in Saccharomyces cerevisiae

    Science.gov (United States)

    Hodges, Amelia J.; Gallegos, Isaura J.; Laughery, Marian F.; Meas, Rithy; Tran, Linh; Wyrick, John J.

    2015-01-01

    A critical feature of the intermolecular contacts that bind DNA to the histone octamer is the series of histone arginine residues that insert into the DNA minor groove at each superhelical location where the minor groove faces the histone octamer. One of these “sprocket” arginine residues, histone H4 R45, significantly affects chromatin structure in vivo and is lethal when mutated to alanine or cysteine in Saccharomyces cerevisiae (budding yeast). However, the roles of the remaining sprocket arginine residues (H3 R63, H3 R83, H2A R43, H2B R36, H2A R78, H3 R49) in chromatin structure and other cellular processes have not been well characterized. We have genetically characterized mutations in each of these histone residues when introduced either singly or in combination to yeast cells. We find that pairs of arginine residues that bind DNA adjacent to the DNA exit/entry sites in the nucleosome are lethal in yeast when mutated in combination and cause a defect in histone occupancy. Furthermore, mutations in individual residues compromise repair of UV-induced DNA lesions and affect gene expression and cryptic transcription. This study reveals simple rules for how the location and structural mode of DNA binding influence the biological function of each histone sprocket arginine residue. PMID:25971662

  8. Detoxification and repair process of ozone injury: From O{sub 3} uptake to gene expression adjustment

    Energy Technology Data Exchange (ETDEWEB)

    Castagna, A., E-mail: castagna@agr.unipi.i [Department of Agricultural Chemistry and Biotechnology, University of Pisa, Via del Borghetto 80, 56124 Pisa (Italy); Ranieri, A., E-mail: aranieri@agr.unipi.i [Department of Agricultural Chemistry and Biotechnology, University of Pisa, Via del Borghetto 80, 56124 Pisa (Italy)

    2009-05-15

    Plants react to O{sub 3} threat by setting up a variety of defensive strategies involving the co-ordinated modulation of stress perception, signalling and metabolic responses. Although stomata largely controls O{sub 3} uptake, differences in O{sub 3} tolerance cannot always be ascribed to changes in stomatal conductance but cell protective and repair processes should be taken into account. O{sub 3}-driven ROS production in the apoplast induces a secondary, active, self-propagating generation of ROS, whose levels must be finely tuned, by many enzymatic and non-enzymatic antioxidant systems, to induce gene activation without determining uncontrolled cell death. Additional signalling molecules, as ethylene, jasmonic and salicylic acid are also crucial to determine the spreading and the containment of leaf lesions. The main recent results obtained on O{sub 3} sensing, signal transduction, ROS formation and detoxification mechanisms are here discussed. - A dissection of the complex network of interacting mechanisms which determine the cell fate under ozone stress.

  9. Histone Sprocket Arginine Residues Are Important for Gene Expression, DNA Repair, and Cell Viability in Saccharomyces cerevisiae.

    Science.gov (United States)

    Hodges, Amelia J; Gallegos, Isaura J; Laughery, Marian F; Meas, Rithy; Tran, Linh; Wyrick, John J

    2015-07-01

    A critical feature of the intermolecular contacts that bind DNA to the histone octamer is the series of histone arginine residues that insert into the DNA minor groove at each superhelical location where the minor groove faces the histone octamer. One of these "sprocket" arginine residues, histone H4 R45, significantly affects chromatin structure in vivo and is lethal when mutated to alanine or cysteine in Saccharomyces cerevisiae (budding yeast). However, the roles of the remaining sprocket arginine residues (H3 R63, H3 R83, H2A R43, H2B R36, H2A R78, H3 R49) in chromatin structure and other cellular processes have not been well characterized. We have genetically characterized mutations in each of these histone residues when introduced either singly or in combination to yeast cells. We find that pairs of arginine residues that bind DNA adjacent to the DNA exit/entry sites in the nucleosome are lethal in yeast when mutated in combination and cause a defect in histone occupancy. Furthermore, mutations in individual residues compromise repair of UV-induced DNA lesions and affect gene expression and cryptic transcription. This study reveals simple rules for how the location and structural mode of DNA binding influence the biological function of each histone sprocket arginine residue. Copyright © 2015 by the Genetics Society of America.

  10. Microsatellite instability and novel mismatch repair gene mutations in northern Chinese population with hereditary non-polyposis colorectal cancer.

    Science.gov (United States)

    Sheng, Jian Qiu; Chan, Tsun Leung; Chan, Yee Wai; Huang, Ji Sheng; Chen, Ji Gui; Zhang, Ming Zhi; Guo, Xiu Lan; Mu, Hong; Chan, Annie Sy; Li, Shi Rong; Yuen, Siu Tsan; Leung, Suet Yi

    2006-01-01

    Hereditary non-polyposis colorectal cancer (HNPCC) syndrome is the most common cause of hereditary colorectal cancer with an early age of onset. Microsatellite instability (MSI) and germline mutation in one of the DNA mismatch repair (MMR) genes are found in the majority of HNPCC families and provide an opportunity for genetic diagnosis and prophylactic screening. The MMR gene mutation spectrum may vary across different populations and be influenced by founder mutations that prevail in specific ethnic groups. China is a big and ancient nation with enormous genetic diversity, which is especially notable between the northern and southern Chinese populations. A MMR gene mutation database for the southern Chinese population based in Hong Kong has been previously established. This study compares the MMR gene mutation spectrum and the MSI of HNPCC between the northern and southern Chinese populations. Twenty-five HNPCC families from northern China were systematically analyzed. The MSI analysis was performed using five loci in the USA National Cancer Institute (NCI) panel (D2S123, D5S346, BAT-25, BAT-26 and BAT-40) by PCR from the tumor and normal tissue. MSH2, MSH6 and MLH1 were performed using immunohistochemical staining. Two founder mutations of MSH2 and MLH1 were examined by PCR base analyses using primers flanking the two deletion sites (c.1452_1455delAATG in MSH2 and 1.8 kb deletion involving exon 11 of MLH1). Of the 25 families collected, 19 met Bethesda guideline (BG) 1 and six met BG3. Twenty-two (15.7%) were extra-colonic cancers with gastric cancer (in seven patients) being the most common cancer type. Of the 25 tumors analyzed, 21 (84%) were high level microsatellite instability (MSI-H) and four (16%) were microsatellite stable (MSS). Eighteen (86%) of the 21 MSI-H tumors showed loss of either the MLH1 or the MSH2 protein. Three MSI-H tumors and all four MSS tumors showed no loss of expression of the three MMR proteins. Out of the 21 patients with MSI

  11. Assessing SNP-SNP interactions among DNA repair, modification and metabolism related pathway genes in breast cancer susceptibility.

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    Yadav Sapkota

    Full Text Available Genome-wide association studies (GWASs have identified low-penetrance common variants (i.e., single nucleotide polymorphisms, SNPs associated with breast cancer susceptibility. Although GWASs are primarily focused on single-locus effects, gene-gene interactions (i.e., epistasis are also assumed to contribute to the genetic risks for complex diseases including breast cancer. While it has been hypothesized that moderately ranked (P value based weak single-locus effects in GWASs could potentially harbor valuable information for evaluating epistasis, we lack systematic efforts to investigate SNPs showing consistent associations with weak statistical significance across independent discovery and replication stages. The objectives of this study were i to select SNPs showing single-locus effects with weak statistical significance for breast cancer in a GWAS and/or candidate-gene studies; ii to replicate these SNPs in an independent set of breast cancer cases and controls; and iii to explore their potential SNP-SNP interactions contributing to breast cancer susceptibility. A total of 17 SNPs related to DNA repair, modification and metabolism pathway genes were selected since these pathways offer a priori knowledge for potential epistatic interactions and an overall role in breast carcinogenesis. The study design included predominantly Caucasian women (2,795 cases and 4,505 controls from Alberta, Canada. We observed two two-way SNP-SNP interactions (APEX1-rs1130409 and RPAP1-rs2297381; MLH1-rs1799977 and MDM2-rs769412 in logistic regression that conferred elevated risks for breast cancer (P(interaction<7.3 × 10(-3. Logic regression identified an interaction involving four SNPs (MBD2-rs4041245, MLH1-rs1799977, MDM2-rs769412, BRCA2-rs1799943 (P(permutation = 2.4 × 10(-3. SNPs involved in SNP-SNP interactions also showed single-locus effects with weak statistical significance, while BRCA2-rs1799943 showed stronger statistical significance (P

  12. Effects of extremely low frequency electromagnetic field and cisplatin on mRNA levels of some DNA repair genes.

    Science.gov (United States)

    Sanie-Jahromi, Fatemeh; Saadat, Iraj; Saadat, Mostafa

    2016-12-01

    It has been shown that exposure to extremely-low frequency (˂300Hz) oscillating electromagnetic field (EMF) can affect gene expression. The effects of different exposure patterns of 50-Hz EMF and co-treatment of EMF plus cisplatin (CDDP) on mRNA levels of seven genes involved in DNA repair pathways (GADD45A, XRCC1, XRCC4, Ku70, Ku80, DNA-PKcs and LIG4) were evaluated. Two 50-Hz EMF intensities (0.25 and 0.50mT), three exposure patterns (5min field-on/5min field-off, 15min field-on/15min field-off, 30min field-on continuously) and two cell lines (MCF-7 and SH-SY5Y) were used. The mRNA levels were measured using quantitative real-time PCR. The examined genes had tendency to be down-regulated in MCF-7 cells treated with EMF. In the pattern of 15min field-on/15min field-off of the 0.50mT EMF, no increase in mRNA levels were observed, but the mRNA levels of GADD45A, XRCC1, XRCC4, Ku80, Ku70, and LIG4 were down-regulated. A significant elevation in IC50 of CDDP was observed when MCF-7 and SH-SY5Y cells were co-treated with CDDP+EMF in comparison with the cells treated with CDDP alone. GADD45A mRNA levels in MCF-7 and SH-SY5Y cells co-treated with CDDP+EMF were increased and at the same time the mRNA levels of XRCC4, Ku80, Ku70 and DNA-PKcs were down-regulated. Present study provides evidence that co-treatment of CDDP+EMF can enhance down-regulation of the genes involved in non-homologous end-joining pathway. It might be suggested that co-treatment of CDDP+EMF could be more promising for sensitizing cancer cells to DNA double strand breaks. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Transcriptomic Response of Purple Willow (Salix purpurea to Arsenic Stress

    Directory of Open Access Journals (Sweden)

    Aymeric Yanitch

    2017-06-01

    Full Text Available Arsenic (As is a toxic element for plants and one of the most common anthropogenic pollutants found at contaminated sites. Despite its severe effects on plant metabolism, several species can accumulate substantial amounts of arsenic and endure the associated stress. However, the genetic mechanisms involved in arsenic tolerance remains obscure in many model plant species used for land decontamination (phytoremediation, including willows. The present study assesses the potential of Salix purpurea cv. ‘Fish Creek’ for arsenic phytoextraction and reveals the genetic responses behind arsenic tolerance, phytoextraction and metabolism. Four weeks of hydroponic exposure to 0, 5, 30 and 100 mg/L revealed that plants were able to tolerate up to 5 mg/L arsenic. Concentrations of 0 and 5 mg/L of arsenic treatment were then used to compare alterations in gene expression of roots, stems and leaves using RNA sequencing. Differential gene expression revealed transcripts encoding proteins putatively involved in entry of arsenic into the roots, storage in vacuoles and potential transport through the plant as well as primary and secondary (indirect toxicity tolerance mechanisms. A major role for tannin as a compound used to relieve cellular toxicity is implicated as well as unexpected expression of the cadmium transporter CAX2, providing a potential means for internal arsenic mobility. These insights into the underpinning genetics of a successful phytoremediating species present novel opportunities for selection of dedicated arsenic tolerant crops as well as the potential to integrate such tolerances into a wider Salix ideotype alongside traits including biomass yield, biomass quality, low agricultural inputs and phytochemical production.

  14. Transcriptomic Response of Purple Willow (Salix purpurea) to Arsenic Stress

    Science.gov (United States)

    Yanitch, Aymeric; Brereton, Nicholas J. B.; Gonzalez, Emmanuel; Labrecque, Michel; Joly, Simon; Pitre, Frederic E.

    2017-01-01

    Arsenic (As) is a toxic element for plants and one of the most common anthropogenic pollutants found at contaminated sites. Despite its severe effects on plant metabolism, several species can accumulate substantial amounts of arsenic and endure the associated stress. However, the genetic mechanisms involved in arsenic tolerance remains obscure in many model plant species used for land decontamination (phytoremediation), including willows. The present study assesses the potential of Salix purpurea cv. ‘Fish Creek’ for arsenic phytoextraction and reveals the genetic responses behind arsenic tolerance, phytoextraction and metabolism. Four weeks of hydroponic exposure to 0, 5, 30 and 100 mg/L revealed that plants were able to tolerate up to 5 mg/L arsenic. Concentrations of 0 and 5 mg/L of arsenic treatment were then used to compare alterations in gene expression of roots, stems and leaves using RNA sequencing. Differential gene expression revealed transcripts encoding proteins putatively involved in entry of arsenic into the roots, storage in vacuoles and potential transport through the plant as well as primary and secondary (indirect) toxicity tolerance mechanisms. A major role for tannin as a compound used to relieve cellular toxicity is implicated as well as unexpected expression of the cadmium transporter CAX2, providing a potential means for internal arsenic mobility. These insights into the underpinning genetics of a successful phytoremediating species present novel opportunities for selection of dedicated arsenic tolerant crops as well as the potential to integrate such tolerances into a wider Salix ideotype alongside traits including biomass yield, biomass quality, low agricultural inputs and phytochemical production. PMID:28702037

  15. Interactive effects of ultraviolet-B radiation and pesticide exposure on DNA photo-adduct accumulation and expression of DNA damage and repair genes in Xenopus laevis embryos

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Shuangying, E-mail: shuangying.yu@ttu.edu [Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, 1207 S. Gilbert Dr., Lubbock, TX 79416 (United States); Tang, Song, E-mail: song.tang@usask.ca [Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, 1207 S. Gilbert Dr., Lubbock, TX 79416 (United States); Mayer, Gregory D., E-mail: greg.mayer@ttu.edu [Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, 1207 S. Gilbert Dr., Lubbock, TX 79416 (United States); Cobb, George P., E-mail: george_cobb@baylor.edu [Department of Environmental Science, Baylor University, One Bear Place #97266, Waco, TX 76798 (United States); Maul, Jonathan D., E-mail: jonathan.maul@ttu.edu [Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, 1207 S. Gilbert Dr., Lubbock, TX 79416 (United States)

    2015-02-15

    Highlights: • Interactive effects of UVB radiation-pesticide co-exposures were examined in frogs. • Responses included induction of DNA photo-adducts and DNA damage and repair genes. • Elevated DNA adduct levels occurred for co-exposures compared to UVB alone. • One mechanism is that pesticides may alter nuclear excision repair gene expression. - Abstract: Pesticide use and ultraviolet-B (UVB) radiation have both been suggested to adversely affect amphibians; however, little is known about their interactive effects. One potential adverse interaction could involve pesticide-induced dysregulation of DNA repair pathways, resulting in greater numbers of DNA photo-adducts from UVB exposure. In the present study, we investigated the interactive effects of UVB radiation and two common pesticides (endosulfan and α-cypermethrin) on induction of DNA photo-adducts and expression of DNA damage and repair related genes in African clawed frog (Xenopus laevis) embryos. We examined 13 genes that are, collectively, involved in stress defense, cell cycle arrest, nucleotide excision repair (NER), base excision repair, mismatch repair, DNA repair regulation, and apoptosis. We exposed X. laevis embryos to 0, 25, and 50 μg/L endosulfan or 0, 2.5, and 5.0 μg/L α-cypermethrin for 96 h, with environmentally relevant exposures of UVB radiation during the last 7 h of the 96 h exposure. We measured the amount of cyclobutane pyrimidine dimers (CPDs) and mRNA abundance of the 13 genes among treatments including control, pesticide only, UVB only, and UVB and pesticide co-exposures. Each of the co-exposure scenarios resulted in elevated CPD levels compared to UVB exposure alone, suggesting an inhibitory effect of endosulfan and α-cypermethrin on CPD repair. This is attributed to results indicating that α-cypermethrin and endosulfan reduced mRNA abundance of XPA and HR23B, respectively, to levels that may affect the initial recognition of DNA lesions. In contrast, both pesticides

  16. Association of nucleotide excision repair pathway gene polymorphisms with gastric cancer and atrophic gastritis risks.

    Science.gov (United States)

    Liu, Jingwei; Sun, Liping; Xu, Qian; Tu, Huakang; He, Caiyun; Xing, Chengzhong; Yuan, Yuan

    2016-02-09

    Polymorphisms of NER genes could change NER ability, thereby altering individual susceptibility to GC. We systematically analyzed 39 SNPs of 8 key genes of NER pathway in 2686 subjects including 898 gastric cancer (GC), 851 atrophic gastritis (AG) and 937 controls (CON) in northern Chinese. SNP genotyping were performed using Sequenom MassARRAY platform. The results demonstrated that DDB2 rs830083 GG genotype was significantly associated with increased GC risk compared with wild-type CC (OR=2.32, P= 6.62 × 10-9); XPC rs2607775 CG genotype conferred a 1.73 increased odds of GC risk than non-cancer subjects compared with wild-type CC (OR=1.73, P= 3.04 × 10-4). The combined detection of these two polymorphisms demonstrated even higher GC risk (OR=3.05). Haplotype analysis suggested that DDB2 rs2029298-rs326222-rs3781619-rs830083 GTAG haplotype was significantly associated with disease risk in each step of CON→AG→GC development (AG vs. CON: OR=2.88, P= 7.51 × 10-7; GC vs. AG: OR=2.90, P=5.68 × 10-15; GC vs. CON: OR=8.42, P=2.22 × 10-15); DDB2 GTAC haplotype was associated with reduced risk of GC compared with CON (OR=0.63, P= 8.31 × 10-12). XPC rs1870134-rs2228000-rs2228001-rs2470352-rs2607775 GCAAG haplotype conferred increased risk of GC compared with AG (OR=1.88, P= 6.98 × 10-4). XPA rs2808668 and drinking, DDB2 rs326222, rs3781619, rs830083 and smoking demonstrated significant interactions in AG; XPC rs2607775 had significant interaction with smoking in GC. In conclusion, NER pathway polymorphisms especially in "damage incision" step were significantly associated with GC risk and had interactions with environment factors. The detection of NER pathway polymorphisms such as DDB2 and XPC might be applied in the prediction of GC risk and personalized prevention in the future. NER pathway polymorphisms especially in "damage incision" step were significantly associated with GC risk and had interactions with environment factors, which might be applied in the

  17. Selection-free gene repair after adenoviral vector transduction of designer nucleases: rescue of dystrophin synthesis in DMD muscle cell populations.

    Science.gov (United States)

    Maggio, Ignazio; Stefanucci, Luca; Janssen, Josephine M; Liu, Jin; Chen, Xiaoyu; Mouly, Vincent; Gonçalves, Manuel A F V

    2016-02-18

    Duchenne muscular dystrophy (DMD) is a fatal X-linked muscle-wasting disorder caused by mutations in the 2.4 Mb dystrophin-encoding DMD gene. The integration of gene delivery and gene editing technologies based on viral vectors and sequence-specific designer nucleases, respectively, constitutes a potential therapeutic modality for permanently repairing defective DMD alleles in patient-derived myogenic cells. Therefore, we sought to investigate the feasibility of combining adenoviral vectors (AdVs) with CRISPR/Cas9 RNA-guided nucleases (RGNs) alone or together with transcriptional activator-like effector nucleases (TALENs), for endogenous DMD repair through non-homologous end-joining (NHEJ). The strategies tested involved; incorporating small insertions or deletions at out-of-frame sequences for reading frame resetting, splice acceptor knockout for DNA-level exon skipping, and RGN-RGN or RGN-TALEN multiplexing for targeted exon(s) removal. We demonstrate that genome editing based on the activation and recruitment of the NHEJ DNA repair pathway after AdV delivery of designer nuclease genes, is a versatile and robust approach for repairing DMD mutations in bulk populations of patient-derived muscle progenitor cells (up to 37% of corrected DMD templates). These results open up a DNA-level genetic medicine strategy in which viral vector-mediated transient designer nuclease expression leads to permanent and regulated dystrophin synthesis from corrected native DMD alleles. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  18. In vivo effects of UV radiation on multiple endpoints and expression profiles of DNA repair and heat shock protein (Hsp) genes in the cycloid copepod Paracyclopina nana

    Energy Technology Data Exchange (ETDEWEB)

    Won, Eun-Ji; Han, Jeonghoon [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Lee, Yeonjung; Kumar, K. Suresh; Shin, Kyung-Hoon [Department of Marine Sciences and Convergent Technology, College of Science and Technology, Hanyang University, Ansan 426-791 (Korea, Republic of); Lee, Su-Jae [Department of Life Sciences, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Park, Heum Gi, E-mail: hgpark@gwnu.ac.kr [Department of Marine Resource Development, College of Life Sciences, Gangneung-Wonju National University, Gangneung 210-702 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@skku.edu [Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

    2015-08-15

    Highlights: • UV-B radiation induced a significant reduction of the re-brooding rate of ovigerous females. • A dose-dependent decrease in food ingestion and the rate of assimilation to the body upon UV radiation. • Expression of base excision repair-associated and hsp chaperoning genes was significantly increased upon UV radiation in P. nana. - Abstract: To evaluate the effects of ultraviolet (UV) radiation on energy acquisition and consumption, the copepod Paracyclopina nana was irradiated with several doses (0–3 kJ/m{sup 2}) of UV. After UV radiation, we measured the re-brooding success, growth pattern of newly hatched nauplii, ingestion rate, and assimilation of diet. In addition, we checked the modulated patterns of DNA repair and heat shock protein (hsp) chaperoning genes of P. nana. UV-B radiation induced a significant reduction (7–87%) of the re-brooding rate of ovigerous females, indicating that UV-induced egg sac damage is closely correlated with a reduction in the hatching rate of UV-irradiated ovigerous female offspring. Using chlorophyll a and stable carbon isotope incubation experiments, we found a dose-dependent decrease (P < 0.05) in food ingestion and the rate of assimilation to the body in response to UV radiation, implying that P. nana has an underlying ability to shift its balanced-energy status from growth and reproduction to DNA repair and adaptation. Also, expression of P. nana base excision repair (BER)-associated genes and hsp chaperoning genes was significantly increased in response to UV radiation in P. nana. These findings indicate that even 1 kJ/m{sup 2} of UV radiation induces a reduction in reproduction and growth patterns, alters the physiological balance and inhibits the ability to cope with UV-induced damage in P. nana.

  19. Association of single nucleotide polymorphisms of DNA repair gene and susceptibility to pancreatic cancer.

    Science.gov (United States)

    Shen, Quan; Tian, Yuwei; Li, Ke; Jiang, Qingfeng; Xue, Huanzhou; Yang, Shujuan

    2015-01-01

    We conducted a case-control study to assess the XRCC4 genes polymorphism and development of pancreatic cancer. A case-control study including 248 cases and 496 controls was conducted in a Chinese population. Genotypes of XRCC4 rs2075685, rs10040363, rs963248 and rs1805377 were determined using Polymerase Chain Reaction combined with a restriction fragment length polymorphism (PCR-RFLP) assay (Applied Biosystems, Foster City, CA, USA). Pancreatic cancer cases were more likely to have a history of diabetes, a higher BMI, family history of cancer and a habit of alcohol drinking when compared with control. Conditional logistic regression analysis showed that individuals carrying TT genotype of XRCC4 rs2075685 was associated with increased risk of pancreatic cancer when compared with GG genotype, and the OR (95% CI) was 1.62 (1.04-2.52). Individuals with GT+TT genotype of XRCC4 rs2075685 were significantly associated with increased risk of pancreatic cancer in those with ever tobacco smoking habit, and the OR (95% CI) was 1.77 (1.07-2.98). In conclusion, our results suggest that XRCC4 rs2075685 polymorphism plays an important role in the risk of pancreatic cancer in a Chinese population, especially in tobacco smokers.

  20. Polymorphisms in DNA Repair Gene XRCC3 and Susceptibility to Breast Cancer in Saudi Females

    Directory of Open Access Journals (Sweden)

    Alaa Mohammed Ali

    2016-01-01

    Full Text Available We investigated three common polymorphisms (SNPs in the XRCC3 gene (rs861539, rs1799794, and rs1799796 in 143 Saudi females suffering from breast cancer (median age = 51.4 years and 145 age matched normal healthy controls. DNA was extracted from whole blood and genotyping was conducted using PCR-RFLP. rs1799794 showed significant association, where AA and AA+AG occurred at a significantly higher frequency in the cancer patients compared to the control group (OR: 28.1; 95% CI: 3.76–21.12; χ2: 22.82; pT and rs1799796 A>G did not show a significant difference when the results in the patients and controls were compared. However, the frequency of rs1799796 differed significantly in patients with different age of diagnosis, tumor grade, and ER and HER2 status. The wild type A allele occurred at a higher frequency in the ER− and HER2− group. Our results among Saudis suggest that some variations in XRCC3 may contribute to breast cancer susceptibility. In conclusion, the results obtained during this study suggest that rs1799794 in XRCC3 shows strong association with breast cancer development in Saudi females.

  1. Polymorphisms in tobacco metabolism and DNA repair genes modulate oral precancer and cancer risk.

    Science.gov (United States)

    Anantharaman, Devasena; Samant, Tanuja A; Sen, Subrata; Mahimkar, Manoj B

    2011-09-01

    The highest rates of oral squamous cell carcinomas are observed in south Asia, particularly in India, where complex forms of tobacco and alcohol exposures exist. Genetic polymorphisms contribute significantly to observed differences in cancer susceptibility. We examined the association of 13 variants in eight genes (rs4646903, rs2031920, rs3813867, GSTM1 null, GSTT1 null, rs1695, rs1138272, rs1799782, rs25487, rs1799791, rs1799793, rs13181 and rs1052133) involved in various stages of tobacco and alcohol metabolism and the risk of leukoplakia and oral cancer (OC) in a case-control study involving 219 oral leukoplakia, 665 OC and 802 age, sex and habit-matched controls. GSTT1 null and rs1695 were inversely associated with oral leukoplakia while GSTM1 null, GSTT1 null, rs2031920, rs3813867 (CYP2E1), and rs13181 were associated with OC. We report that genetic variants associated with premalignant and malignant conditions of the oral cavity differ. The associations appeared to be consistent among smokeless tobacco users, a characteristic risk factor in these parts. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. B lymphocytes of xeroderma pigmentosum or Cockayne syndrome patients with inherited defects in nucleotide excision repair are fully capable of somatic hypermutation of immunoglobulin genes.

    Science.gov (United States)

    Kim, N; Kage, K; Matsuda, F; Lefranc, M P; Storb, U

    1997-08-04

    Recent experiments have strongly suggested that the process of somatic mutation is linked to transcription initiation. It was postulated that a mutator factor loads onto the RNA polymerase and, during elongation, causes transcriptional arrest that activates DNA repair, thus occasionally causing errors in the DNA sequence. We report the analysis of the role of one of the known DNA repair systems, nucleotide excision repair (NER), in somatic mutation. Epstein-Barrvirus-transformed B cells from patients with defects in NER (XP-B, XP-D, XP-V, and CS-A) were studied. Their heavy and light chain genes show a high frequency of point mutations in the variable (V), but not in the constant (C) regions. This suggests that these B cells can undergo somatic hypermutation despite significant defects in NER. Thus, it is doubtful that NER is an essential part of the mechanism of somatic hypermutation of Ig genes. As an aside, NER seems also not involved in Ig gene switch recombination.

  3. Insertional Mutagenesis by CRISPR/Cas9 Ribonucleoprotein Gene Editing in Cells Targeted for Point Mutation Repair Directed by Short Single-Stranded DNA Oligonucleotides.

    Science.gov (United States)

    Rivera-Torres, Natalia; Banas, Kelly; Bialk, Pawel; Bloh, Kevin M; Kmiec, Eric B

    2017-01-01

    CRISPR/Cas9 and single-stranded DNA oligonucleotides (ssODNs) have been used to direct the repair of a single base mutation in human genes. Here, we examine a method designed to increase the precision of RNA guided genome editing in human cells by utilizing a CRISPR/Cas9 ribonucleoprotein (RNP) complex to initiate DNA cleavage. The RNP is assembled in vitro and induces a double stranded break at a specific site surrounding the mutant base designated for correction by the ssODN. We use an integrated mutant eGFP gene, bearing a single base change rendering the expressed protein nonfunctional, as a single copy target in HCT 116 cells. We observe significant gene correction activity of the mutant base, promoted by the RNP and single-stranded DNA oligonucleotide with validation through genotypic and phenotypic readout. We demonstrate that all individual components must be present to obtain successful gene editing. Importantly, we examine the genotype of individually sorted corrected and uncorrected clonally expanded cell populations for the mutagenic footprint left by the action of these gene editing tools. While the DNA sequence of the corrected population is exact with no adjacent sequence modification, the uncorrected population exhibits heterogeneous mutagenicity with a wide variety of deletions and insertions surrounding the target site. We designate this type of DNA aberration as on-site mutagenicity. Analyses of two clonal populations bearing specific DNA insertions surrounding the target site, indicate that point mutation repair has occurred at the level of the gene. The phenotype, however, is not rescued because a section of the single-stranded oligonucleotide has been inserted altering the reading frame and generating truncated proteins. These data illustrate the importance of analysing mutagenicity in uncorrected cells. Our results also form the basis of a simple model for point mutation repair directed by a short single-stranded DNA oligonucleotides and

  4. DNA repair gene expression level in peripheral blood and tumour tissue from non-small cell lung cancer and head and neck squamous cell cancer patients.

    Science.gov (United States)

    Schena, Marina; Guarrera, Simonetta; Buffoni, Lucio; Salvadori, Angelica; Voglino, Floriana; Allione, Alessandra; Pecorari, Giancarlo; Ruffini, Enrico; Garzino-Demo, Paolo; Bustreo, Sara; Consito, Lorena; Bironzo, Paolo; Matullo, Giuseppe

    2012-04-01

    The nucleotide excision repair pathway is crucial for cellular DNA integrity and the ERCC1 helicase is also potentially involved in resistance to platinum-based chemotherapy, and high levels of ERCC1 mRNA in tumours have been associated with cisplatin resistance in different human cancers. The aim of this work was to investigate the correlation between DNA repair gene expression levels in tumour tissue, normal tissue and peripheral blood samples from patients with two common human cancers, non-small cell lung cancer (NSCLC) and squamous cell carcinoma of the head and neck (HNSCC), to test if blood gene expression could be a proxy for tumour tissue gene expression to predict response to platinum-based chemotherapy. Using RT-qPCR we determined ERCC1, ERCC2, ERCC4, XPA, XPC, XRCC1, XRCC3, APEX, OGG1, MGMT mRNA levels in fresh NSCLC, normal lung and HNSCC tissue, as well as blood, from NSCLC and HNSCC patients who were treated surgically. Target gene expression in NSCLC and HNSCC tissue was higher than in blood. A statistically significant correlation (pAPEX, ERCC1, ERCC2, ERCC4, XRCC1 and XRCC3 in HNSCC. The existence of a significant correlation between blood and tumour tissue expression of some genes of clinical interest, such as ERCC1 in NSCLC and HNSCC, could allow the introduction in clinical practice of a simple test that would measure mRNA levels of DNA repair genes in peripheral blood samples instead of tissue samples to determine prognostic and predictive factors in NSCLC and HNSCC patients. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Binational Arsenic Exposure Survey: Methodology and Estimated Arsenic Intake from Drinking Water and Urinary Arsenic Concentrations

    Directory of Open Access Journals (Sweden)

    Robin B. Harris

    2012-03-01

    Full Text Available The Binational Arsenic Exposure Survey (BAsES was designed to evaluate probable arsenic exposures in selected areas of southern Arizona and northern Mexico, two regions with known elevated levels of arsenic in groundwater reserves. This paper describes the methodology of BAsES and the relationship between estimated arsenic intake from beverages and arsenic output in urine. Households from eight communities were selected for their varying groundwater arsenic concentrations in Arizona, USA and Sonora, Mexico. Adults responded to questionnaires and provided dietary information. A first morning urine void and water from all household drinking sources were collected. Associations between urinary arsenic concentration (total, organic, inorganic and estimated level of arsenic consumed from water and other beverages were evaluated through crude associations and by random effects models. Median estimated total arsenic intake from beverages among participants from Arizona communities ranged from 1.7 to 14.1 µg/day compared to 0.6 to 3.4 µg/day among those from Mexico communities. In contrast, median urinary inorganic arsenic concentrations were greatest among participants from Hermosillo, Mexico (6.2 µg/L whereas a high of 2.0 µg/L was found among participants from Ajo, Arizona. Estimated arsenic intake from drinking water was associated with urinary total arsenic concentration (p < 0.001, urinary inorganic arsenic concentration (p < 0.001, and urinary sum of species (p < 0.001. Urinary arsenic concentrations increased between 7% and 12% for each one percent increase in arsenic consumed from drinking water. Variability in arsenic intake from beverages and urinary arsenic output yielded counter intuitive results. Estimated intake of arsenic from all beverages was greatest among Arizonans yet participants in Mexico had higher urinary total and inorganic arsenic concentrations. Other contributors to urinary arsenic concentrations should be evaluated.

  6. Factors determining sensitivity and resistance of tumor cells to arsenic trioxide.

    Directory of Open Access Journals (Sweden)

    Serkan Sertel

    Full Text Available Previously, arsenic trioxide showed impressive regression rates of acute promyelocytic leukemia. Here, we investigated molecular determinants of sensitivity and resistance of cell lines of different tumor types towards arsenic trioxide. Arsenic trioxide was the most cytotoxic compound among 8 arsenicals investigated in the NCI cell line panel. We correlated transcriptome-wide microarray-based mRNA expression to the IC(50 values for arsenic trioxide by bioinformatic approaches (COMPARE and hierarchical cluster analyses, Ingenuity signaling pathway analysis. Among the identified pathways were signaling routes for p53, integrin-linked kinase, and actin cytoskeleton. Genes from these pathways significantly predicted cellular response to arsenic trioxide. Then, we analyzed whether classical drug resistance factors may also play a role for arsenic trioxide. Cell lines transfected with cDNAs for catalase, thioredoxin, or the anti-apoptotic bcl-2 gene were more resistant to arsenic trioxide than mock vector transfected cells. Multidrug-resistant cells overexpressing the MDR1, MRP1 or BCRP genes were not cross-resistant to arsenic trioxide. Our approach revealed that response of tumor cells towards arsenic trioxide is multi-factorial.

  7. Chronic Arsenic poisoning.

    Science.gov (United States)

    Ahsan, Tasnim; Zehra, Kaneez; Munshi, Alia; Ahsan, Samiah

    2009-02-01

    Chronic Arsenic Toxicity may have varied clinical presentations ranging from non-cancerous manifestations to malignancy of skin and different internal organs. Dermal lesions such as hyper pigmentation and hyperkeratosis, predominantly over palms and soles are diagnostic of Chronic Arsenicosis. We report two cases from a family living in Sukkur who presented with classical skin lesions described in Chronic Arsenicosis. The urine, nail and hair samples of these patients contained markedly elevated levels of arsenic. Also the water samples from their household and the neighbouring households were found to have alarming levels of inorganic Arsenic.

  8. Cancer spectrum in DNA mismatch repair gene mutation carriers: results from a hospital based Lynch syndrome registry.

    Science.gov (United States)

    Pande, Mala; Wei, Chongjuan; Chen, Jinyun; Amos, Christopher I; Lynch, Patrick M; Lu, Karen H; Lucio, Laura A; Boyd-Rogers, Stephanie G; Bannon, Sarah A; Mork, Maureen E; Frazier, Marsha L

    2012-09-01

    The spectrum of cancers seen in a hospital based Lynch syndrome registry of mismatch repair gene mutation carriers was examined to determine the distribution of cancers and examine excess cancer risk. Overall there were 504 cancers recorded in 368 mutation carriers from 176 families. These included 236 (46.8 %) colorectal and 268 (53.2 %) extracolonic cancers. MLH1 mutation carriers had a higher frequency of colorectal cancers whereas MSH2, MSH6 and PMS2 mutation carriers had more extracolonic cancers although these differences were not statistically significant. Men had fewer extracolonic cancers than colorectal (45.3 vs. 54.7 %), whereas women had more extracolonic than colorectal cancers (59.0 vs. 41.0 %). The mean age at diagnosis overall for extracolonic cancers was older than for colorectal, 49.1 versus 44.8 years (P ≤ 0.001). As expected, the index cancer was colorectal in 58.1 % of patients and among the extracolonic index cancers, endometrial was the most common (13.8 %). A significant number of non-Lynch syndrome index cancers were recorded including breast (n = 5) prostate (n = 3), thyroid (n = 3), cervix (n = 3), melanoma (n = 3), and 1 case each of thymoma, sinus cavity, and adenocarcinoma of the lung. However, standardized incidence ratios calculated to assess excess cancer risk showed that only those cancers known to be associated with Lynch syndrome were significant in our sample. We found that Lynch syndrome patients can often present with cancers that are not considered part of Lynch syndrome. This has clinical relevance both for diagnosis of Lynch syndrome and surveillance for cancers of different sites during follow-up of these patients.

  9. Molecular spectrum of excision repair cross-complementation group 8 gene defects in Chinese patients with Cockayne syndrome type A.

    Science.gov (United States)

    Wang, Xiaozhu; Huang, Yu; Yan, Ming; Li, Jiuwei; Ding, Changhong; Jin, Hong; Fang, Fang; Yang, Yanling; Wu, Baiyan; Chen, Dafang

    2017-10-20

    There are two genetics complementary groups Cockayne syndrome type A and B (CS-A and CS-B OMIM 216400, 133540), which is a rare autosomal recessive segmental progeroid syndrome. Homozygous or compound heterozygous mutations in the excision repair cross-complementation group 8 gene (ERCC8) result in CS-A, and mutations in ERCC6 result in CS-B. Homozygous ERCC6/ERCC8 mutations also result in UV-sensitive syndrome. In this study, twenty-one Han Chinese patients with CS were investigated to identify mutations in ERCC8/ERCC6, of which thirteen cases with CS-A were identified with the mutations of ERCC8. There are five types mutations of ERCC8 in our study, such as exon 4 rearrangement, c.394_398delTTACA, c.299insA, c.843 + 2 T > C, and c.2 T > A. An estimated frequency of exon 4 rearrangement accounts for 69.23% and c.394_398delTTACA accounts for 11.53% in our cohort. Haplotype analysis revealed that the exon 4 rearrangement and c.394_398delTTACA mutations originated from a common founder in the Chinese population respectively. With the identification of three novel ERCC8 mutations, this study expanded the molecular spectrum of known ERCC8 defects, and furthermore, suggests that the exon 4 rearrangement and c.394_398delTTACA mutations may be a common underlying cause of CS-A in the Chinese population, which is different from that in other populations.

  10. Identification of candidate polymorphisms on stress oxidative and DNA damage repair genes related with clinical outcome in breast cancer patients.

    Science.gov (United States)

    Rodrigues, Patricia; Furriol, Jessica; Bermejo, Begoña; Chaves, Felipe Javier; Lluch, Ana; Eroles, Pilar

    2012-12-05

    Diverse polymorphisms have been associated with the predisposition to develop cancer. On fewer occasions, they have been related to the evolution of the disease and to different responses to treatment. Previous studies of our group have associated polymorphisms on genes related to oxidative stress (rs3736729 on GCLC and rs207454 on XDH) and DNA damage repair (rs1052133 on OGG1) with a predisposition to develop breast cancer. In the present work, we have evaluated the hypothesis that these polymorphisms also play a role in a patient's survival. A population-based cohort study of 470 women diagnosed with primary breast cancer and a median follow up of 52.44 months was conducted to examine the disease-free and overall survival in rs3736729, rs207454 and rs1052133 genetic variants. Adjusted Cox regression analysis was used to that end. The Kaplan-Meier analysis shows that rs3736729 on GCLC presents a significant association with disease-free survival and overall survival. The polymorphisms rs1052133 on OGG1 and rs207454 on XDH show a trend of association with overall survival. The analysis based on hormonal receptor status revealed a stronger association. The CC genotype on rs207454 (XDH) was significantly associated with lower time of disease free survival (p = 0.024) in progesterone receptor negative (PGR-) patients and rs3736729 (GCLC) was significantly associated with disease free survival (p = 0.001) and overall survival (p = 0.012) in the subgroup of estrogen receptor negative (ER-) patients. This work suggests that unfavorable genetic variants in the rs207454 (XDH) and rs3736729 (GCLC) polymorphisms may act as predictors of the outcome in negative progesterone receptor and negative estrogen receptor breast cancer patients, respectively.

  11. Identification of Candidate Polymorphisms on Stress Oxidative and DNA Damage Repair Genes Related with Clinical Outcome in Breast Cancer Patients

    Directory of Open Access Journals (Sweden)

    Patricia Rodrigues

    2012-12-01

    Full Text Available Diverse polymorphisms have been associated with the predisposition to develop cancer. On fewer occasions, they have been related to the evolution of the disease and to different responses to treatment. Previous studies of our group have associated polymorphisms on genes related to oxidative stress (rs3736729 on GCLC and rs207454 on XDH and DNA damage repair (rs1052133 on OGG1 with a predisposition to develop breast cancer. In the present work, we have evaluated the hypothesis that these polymorphisms also play a role in a patient’s survival. A population-based cohort study of 470 women diagnosed with primary breast cancer and a median follow up of 52.44 months was conducted to examine the disease-free and overall survival in rs3736729, rs207454 and rs1052133 genetic variants. Adjusted Cox regression analysis was used to that end. The Kaplan-Meier analysis shows that rs3736729 on GCLC presents a significant association with disease-free survival and overall survival. The polymorphisms rs1052133 on OGG1 and rs207454 on XDH show a trend of association with overall survival. The analysis based on hormonal receptor status revealed a stronger association. The CC genotype on rs207454 (XDH was significantly associated with lower time of disease free survival (p = 0.024 in progesterone receptor negative (PGR− patients and rs3736729 (GCLC was significantly associated with disease free survival (p = 0.001 and overall survival (p = 0.012 in the subgroup of estrogen receptor negative (ER− patients. This work suggests that unfavorable genetic variants in the rs207454 (XDH and rs3736729 (GCLC polymorphisms may act as predictors of the outcome in negative progesterone receptor and negative estrogen receptor breast cancer patients, respectively.

  12. Oxidative stress and replication-independent DNA breakage induced by arsenic in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Ireneusz Litwin

    Full Text Available Arsenic is a well-established human carcinogen of poorly understood mechanism of genotoxicity. It is generally accepted that arsenic acts indirectly by generating oxidative DNA damage that can be converted to replication-dependent DNA double-strand breaks (DSBs, as well as by interfering with DNA repair pathways and DNA methylation. Here we show that in budding yeast arsenic also causes replication and transcription-independent DSBs in all phases of the cell cycle, suggesting a direct genotoxic mode of arsenic action. This is accompanied by DNA damage checkpoint activation resulting in cell cycle delays in S and G2/M phases in wild type cells. In G1 phase, arsenic activates DNA damage response only in the absence of the Yku70-Yku80 complex which normally binds to DNA ends and inhibits resection of DSBs. This strongly indicates that DSBs are produced by arsenic in G1 but DNA ends are protected by Yku70-Yku80 and thus invisible for the checkpoint response. Arsenic-induced DSBs are processed by homologous recombination (HR, as shown by Rfa1 and Rad52 nuclear foci formation and requirement of HR proteins for cell survival during arsenic exposure. We show further that arsenic greatly sensitizes yeast to phleomycin as simultaneous treatment results in profound accumulation of DSBs. Importantly, we observed a similar response in fission yeast Schizosaccharomyces pombe, suggesting that the mechanisms of As(III genotoxicity may be conserved in other organisms.

  13. Oxidative stress and replication-independent DNA breakage induced by arsenic in Saccharomyces cerevisiae.

    Science.gov (United States)

    Litwin, Ireneusz; Bocer, Tomasz; Dziadkowiec, Dorota; Wysocki, Robert

    2013-01-01

    Arsenic is a well-established human carcinogen of poorly understood mechanism of genotoxicity. It is generally accepted that arsenic acts indirectly by generating oxidative DNA damage that can be converted to replication-dependent DNA double-strand breaks (DSBs), as well as by interfering with DNA repair pathways and DNA methylation. Here we show that in budding yeast arsenic also causes replication and transcription-independent DSBs in all phases of the cell cycle, suggesting a direct genotoxic mode of arsenic action. This is accompanied by DNA damage checkpoint activation resulting in cell cycle delays in S and G2/M phases in wild type cells. In G1 phase, arsenic activates DNA damage response only in the absence of the Yku70-Yku80 complex which normally binds to DNA ends and inhibits resection of DSBs. This strongly indicates that DSBs are produced by arsenic in G1 but DNA ends are protected by Yku70-Yku80 and thus invisible for the checkpoint response. Arsenic-induced DSBs are processed by homologous recombination (HR), as shown by Rfa1 and Rad52 nuclear foci formation and requirement of HR proteins for cell survival during arsenic exposure. We show further that arsenic greatly sensitizes yeast to phleomycin as simultaneous treatment results in profound accumulation of DSBs. Importantly, we observed a similar response in fission yeast Schizosaccharomyces pombe, suggesting that the mechanisms of As(III) genotoxicity may be conserved in other organisms.

  14. Role of Aspergillus niger acrA in Arsenic Resistance and Its Use as the Basis for an Arsenic Biosensor

    Science.gov (United States)

    Choe, Se-In; Gravelat, Fabrice N.; Al Abdallah, Qusai; Lee, Mark J.; Gibbs, Bernard F.

    2012-01-01

    Arsenic contamination of groundwater sources is a major issue worldwide, since exposure to high levels of arsenic has been linked to a variety of health problems. Effective methods of detection are thus greatly needed as preventive measures. In an effort to develop a fungal biosensor for arsenic, we first identified seven putative arsenic metabolism and transport genes in Aspergillus niger, a widely used industrial organism that is generally regarded as safe (GRAS). Among the genes tested for RNA expression in response to arsenate, acrA, encoding a putative plasma membrane arsenite efflux pump, displayed an over 200-fold increase in gene expression in response to arsenate. We characterized the function of this A. niger protein in arsenic efflux by gene knockout and confirmed that AcrA was located at the cell membrane using an enhanced green fluorescent protein (eGFP) fusion construct. Based on our observations, we developed a putative biosensor strain containing a construct of the native promoter of acrA fused with egfp. We analyzed the fluorescence of this biosensor strain in the presence of arsenic using confocal microscopy and spectrofluorimetry. The biosensor strain reliably detected both arsenite and arsenate in the range of 1.8 to 180 μg/liter, which encompasses the threshold concentrations for drinking water set by the World Health Organization (10 and 50 μg/liter). PMID:22467499

  15. Arsenic speciation results

    Data.gov (United States)

    U.S. Environmental Protection Agency — Linear combination fitting results of synchrotron data to determine arsenic speciation in soil samples. This dataset is associated with the following publication:...

  16. Arsenic Trioxide Injection

    Science.gov (United States)

    ... have not been helped by other types of chemotherapy or whose condition has improved but then worsened following treatment with other types of chemotherapy. Arsenic trioxide is in a class of medications ...

  17. Chromated Arsenicals (CCA)

    Science.gov (United States)

    Chromated copper arsenate (CCA) is a wood preservative pesticide containing chromium, copper, and arsenic that protects wood against termites, fungi, mites and other pests that can degrade or threaten the integrity of wood products.

  18. Arsenic immunotoxicity: a review

    National Research Council Canada - National Science Library

    Dangleben, Nygerma L; Skibola, Christine F; Smith, Martyn T

    2013-01-01

    Exposure to arsenic (As) is a global public health problem because of its association with various cancers and numerous other pathological effects, and millions of people worldwide are exposed to As on a regular basis...

  19. The Smc5-Smc6 complex and SUMO modification of Rad52 regulates recombinational repair at the ribosomal gene locus

    DEFF Research Database (Denmark)

    Torres-Rosell, Jordi; Sunjevaric, Ivana; De Piccoli, Giacomo

    2007-01-01

    Homologous recombination (HR) is crucial for maintaining genome integrity by repairing DNA double-strand breaks (DSBs) and rescuing collapsed replication forks. In contrast, uncontrolled HR can lead to chromosome translocations, loss of heterozygosity, and deletion of repetitive sequences. Contro...

  20. Comprehensive SNP scan of DNA repair and DNA damage response genes reveal multiple susceptibility loci conferring risk to tobacco associated leukoplakia and oral cancer.

    Science.gov (United States)

    Mondal, Pinaki; Datta, Sayantan; Maiti, Guru Prasad; Baral, Aradhita; Jha, Ganga Nath; Panda, Chinmay Kumar; Chowdhury, Shantanu; Ghosh, Saurabh; Roy, Bidyut; Roychoudhury, Susanta

    2013-01-01

    Polymorphic variants of DNA repair and damage response genes play major role in carcinogenesis. These variants are suspected as predisposition factors to Oral Squamous Cell Carcinoma (OSCC). For identification of susceptible variants affecting OSCC development in Indian population, the "maximally informative" method of SNP selection from HapMap data to non-HapMap populations was applied. Three hundred twenty-five SNPs from 11 key genes involved in double strand break repair, mismatch repair and DNA damage response pathways were genotyped on a total of 373 OSCC, 253 leukoplakia and 535 unrelated control individuals. The significantly associated SNPs were validated in an additional cohort of 144 OSCC patients and 160 controls. The rs12515548 of MSH3 showed significant association with OSCC both in the discovery and validation phases (discovery P-value: 1.43E-05, replication P-value: 4.84E-03). Two SNPs (rs12360870 of MRE11A, P-value: 2.37E-07 and rs7003908 of PRKDC, P-value: 7.99E-05) were found to be significantly associated only with leukoplakia. Stratification of subjects based on amount of tobacco consumption identified SNPs that were associated with either high or low tobacco exposed group. The study reveals a synergism between associated SNPs and lifestyle factors in predisposition to OSCC and leukoplakia.

  1. Emergence of a daptomycin-non-susceptible Enterococcus faecium strain that encodes mutations in DNA repair genes after high-dose daptomycin therapy.

    Science.gov (United States)

    Matono, Takashi; Hayakawa, Kayoko; Hirai, Risen; Tanimura, Akira; Yamamoto, Kei; Fujiya, Yoshihiro; Mawatari, Momoko; Kutsuna, Satoshi; Takeshita, Nozomi; Mezaki, Kazuhisa; Ohmagari, Norio; Miyoshi-Akiyama, Tohru

    2016-04-01

    An increasing number of reports have documented the emergence of daptomycin-nonsusceptible Enterococcus in patients during daptomycin therapy. Even though several mechanisms for daptomycin-nonsusceptibility have been suggested, the potential genetic mutations which might contribute to the daptomycin-nonsusceptibility are not fully understood. We isolated a vancomycin-susceptible, daptomycin nonsusceptible Enterococcus faecium strain from a patient with acute lymphocytic leukemia who received high-dose daptomycin therapy for E. faecium endocarditis. Whole-genome sequencing analysis revealed mutations within genes encoding DNA repair proteins MutL and RecJ of the daptomycin-nonsusceptible Enterococcus strain which might have facilitated its emergence. We identified the mutations of DNA mismatch repair genes in a clinical isolate of daptomycin nonsusceptible E. faecium which emerged in spite of high-dose daptomycin therapy. The finding implicates the possible association of DNA repair mechanism and daptomycin resistance. Careful monitoring is necessary to avoid the emergence of daptomycin non-susceptible isolates of E. faecium and particularly in cases of long-term daptomycin use or in immunocompromised patients.

  2. Arsenic responsive microRNAs in vivo and their potential involvement in arsenic-induced oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Xuefeng, E-mail: xuefengr@buffalo.edu [Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, The State University of New York, Buffalo, NY 14214 (United States); Department of Pharmacology and Toxicology, School of Biomedical Sciences, The State University of New York, Buffalo, NY 14214 (United States); Gaile, Daniel P. [Department of Biostatistics, School of Public Health and Health Professions, the State University of New York, Buffalo, NY 14214 (United States); Gong, Zhihong [Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, The State University of New York, Buffalo, NY 14214 (United States); Qiu, Wenting [School of Public Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035 (China); Ge, Yichen [Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, The State University of New York, Buffalo, NY 14214 (United States); Zhang, Chuanwu; Huang, Chenping; Yan, Hongtao [School of Public Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035 (China); Olson, James R. [Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, The State University of New York, Buffalo, NY 14214 (United States); Department of Pharmacology and Toxicology, School of Biomedical Sciences, The State University of New York, Buffalo, NY 14214 (United States); Kavanagh, Terrance J. [Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195 (United States); Wu, Hongmei, E-mail: hongmeiwwu@hotmail.com [School of Public Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035 (China)

    2015-03-15

    Arsenic exposure is postulated to modify microRNA (miRNA) expression, leading to changes of gene expression and toxicities, but studies relating the responses of miRNAs to arsenic exposure are lacking, especially with respect to in vivo studies. We utilized high-throughput sequencing technology and generated miRNA expression profiles of liver tissues from Sprague Dawley (SD) rats exposed to various concentrations of sodium arsenite (0, 0.1, 1, 10 and 100 mg/L) for 60 days. Unsupervised hierarchical clustering analysis of the miRNA expression profiles clustered the SD rats into different groups based on the arsenic exposure status, indicating a highly significant association between arsenic exposure and cluster membership (p-value of 0.0012). Multiple miRNA expressions were altered by arsenic in an exposure concentration-dependent manner. Among the identified arsenic-responsive miRNAs, several are predicted to target Nfe2l2-regulated antioxidant genes, including glutamate–cysteine ligase (GCL) catalytic subunit (GCLC) and modifier subunit (GCLM) which are involved in glutathione (GSH) synthesis. Exposure to low concentrations of arsenic increased mRNA expression for Gclc and Gclm, while high concentrations significantly reduced their expression, which were correlated to changes in hepatic GCL activity and GSH level. Moreover, our data suggested that other mechanisms, e.g., miRNAs, rather than Nfe2l2-signaling pathway, could be involved in the regulation of mRNA expression of Gclc and Gclm post-arsenic exposure in vivo. Together, our findings show that arsenic exposure disrupts the genome-wide expression of miRNAs in vivo, which could lead to the biological consequence, such as an altered balance of antioxidant defense and oxidative stress. - Highlights: • Chronic arsenic exposure induces changes of hepatic miRNA expression profiles. • Hepatic GCL activity and GSH level in rats are altered following arsenic exposure. • Arsenic induced GCL expression change is

  3. Increased methylation of repetitive elements and DNA repair genes is associated with higher DNA oxidation in children in an urbanized, industrial environment.

    Science.gov (United States)

    Alvarado-Cruz, Isabel; Sánchez-Guerra, Marco; Hernández-Cadena, Leticia; De Vizcaya-Ruiz, Andrea; Mugica, Violeta; Pelallo-Martínez, Nadia Azenet; Solís-Heredia, María de Jesús; Byun, Hyang-Min; Baccarelli, Andrea; Quintanilla-Vega, Betzabet

    2017-01-01

    DNA methylation in DNA repair genes participates in the DNA damage regulation. Particulate matter (PM), which has metals and polycyclic aromatic hydrocarbons (PAHs) adsorbed, among others has been linked to adverse health outcomes and may modify DNA methylation. To evaluate PM exposure impact on repetitive elements and gene-specific DNA methylation and DNA damage, we conducted a cross-sectional study in 150 schoolchildren (7-10 years old) from an urbanized, industrial area of the metropolitan area of Mexico City (MAMC), which frequently exhibits PM concentrations above safety standards. Methylation (5mC) of long interspersed nuclear element-1 (LINE1) and DNA repair gene (OGG1, APEX, and PARP1) was assessed by pyrosequencing in peripheral mononuclear cells, DNA damage by comet assay and DNA oxidation by 8-OHdG content. PAH and metal contents in PM10 (≤10μm aerodynamic diameter) were determined by HPLC-MS and ICP-AES, respectively. Multiple regression analysis between DNA methylation, DNA damage, and PM10 exposure showed that PM10 was significantly associated with oxidative DNA damage; a 1% increase in 5mC at all CpG sites in PARP1 promoter was associated with a 35% increase in 8-OHdG, while a 1% increase at 1, 2, and 3 CpG sites resulted in 38, 9, and 56% increments, respectively. An increase of 10pg/m3 in benzo[b]fluoranthene content of PM10 was associated with a 6% increase in LINE1 methylation. Acenaphthene, indene [1,2,3-cd] pyrene, and pyrene concentrations correlated with higher dinucleotide methylation in OGG1, APEX and PARP1 genes, respectively. Vanadium concentration correlated with increased methylation at selected APEX and PARP1 CpG sites. DNA repair gene methylation was significantly correlated with DNA damage and with specific PM10-associated PAHs and Vanadium. Data suggest that exposure to PM and its components are associated with differences in DNA methylation of repair genes in children, which may contribute to DNA damage. Copyright © 2016

  4. Ameliorative potential of Psidium guajava in induced arsenic toxicity in Wistar rats

    Directory of Open Access Journals (Sweden)

    Manju Roy and Sushovan Roy

    2011-04-01

    Full Text Available The study was undertaken to determine the effect of Psidium.guajava leaf extract on arsenic induced biochemical alterations in Wistar rats. Significant (P<0.05 increased glucose serum urea nitrogen and serum creatinine was observed whereas non significant decrease in total protein, calcium and phosphorus was observed. It is concluded that kidney damage caused by arsenic can be repaired up to some extent by AEPG50. [Veterinary World 2011; 4(2.000: 82-83

  5. Arsenic inhibits hedgehog signaling during P19 cell differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jui Tung [Environmental Toxicology Program, Clemson University, 132 Long Hall, Clemson, SC 29634 (United States); Bain, Lisa J., E-mail: lbain@clemson.edu [Environmental Toxicology Program, Clemson University, 132 Long Hall, Clemson, SC 29634 (United States); Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC 29634 (United States)

    2014-12-15

    Arsenic is a toxicant found in ground water around the world, and human exposure mainly comes from drinking water or from crops grown in areas containing arsenic in soils or water. Epidemiological studies have shown that arsenic exposure during development decreased intellectual function, reduced birth weight, and altered locomotor activity, while in vitro studies have shown that arsenite decreased muscle and neuronal cell differentiation. The sonic hedgehog (Shh) signaling pathway plays an important role during the differentiation of both neurons and skeletal muscle. The purpose of this study was to investigate whether arsenic can disrupt Shh signaling in P19 mouse embryonic stem cells, leading to changes muscle and neuronal cell differentiation. P19 embryonic stem cells were exposed to 0, 0.25, or 0.5 μM of sodium arsenite for up to 9 days during cell differentiation. We found that arsenite exposure significantly reduced transcript levels of genes in the Shh pathway in both a time and dose-dependent manner. This included the Shh ligand, which was decreased 2- to 3-fold, the Gli2 transcription factor, which was decreased 2- to 3-fold, and its downstream target gene Ascl1, which was decreased 5-fold. GLI2 protein levels and transcriptional activity were also reduced. However, arsenic did not alter GLI2 primary cilium accumulation or nuclear translocation. Moreover, additional extracellular SHH rescued the inhibitory effects of arsenic on cellular differentiation due to an increase in GLI binding activity. Taken together, we conclude that arsenic exposure affected Shh signaling, ultimately decreasing the expression of the Gli2 transcription factor. These results suggest a mechanism by which arsenic disrupts cell differentiation. - Highlights: • Arsenic exposure decreases sonic hedgehog pathway-related gene expression. • Arsenic decreases GLI2 protein levels and transcriptional activity in P19 cells. • Arsenic exposure does not alter the levels of SHH

  6. Genetic polymorphisms in DNA base excision repair gene XRCC1 and the risk of squamous cell carcinoma of the head and neck

    Directory of Open Access Journals (Sweden)

    Pietruszewska Wioletta

    2009-03-01

    Full Text Available Abstract Background The genes of base excision repair (BER pathway have been extensively studied in the association with various human cancers. We performed a case-control study to test the association between two common single nucleotide polymorphisms (SNPs of XRCC1 gene with human head and neck squamous cell carcinoma (HNSCC. Methods The genotype analysis of Arg194Trp and Arg399Gln gene polymorphisms for 92 HNSCC patients and 124 controls of cancer free subjects, in Polish population were performed using the PCR-based restriction fragment length polymorphism (PCR-RFLP with endonuclease MspI. Results No altered risk has been found individually for these SNPs, however haplotypes analysis showed high association with head and neck cancer. The highest frequency, according to wild-type of Arg194Arg and Arg399Arg genotypes, was identified for Arg194Trp-Arg399Arg haplotype (OR, 2.96; 95% CI, 1.01–8.80. Conclusion Finally, we identified the combined Arg194Trp-Arg399Arg genotype of base excision repair gene XRCC1 that was associated with HNSCC and may have an impact on identification of a high-risk cancer population.

  7. Allelism of Saccharomyces cerevisiae gene PSO10, involved in error-prone repair of psoralen-induced DNA damage, with SUMO ligase-encoding MMS21.

    Science.gov (United States)

    Hoch, Nícolas C; Santos, Rafael S; Rosa, Renato M; Machado, Roseane M; Saffi, Jenifer; Brendel, Martin; Henriques, João A P

    2008-06-01

    In order to extend the understanding of the genetical and biochemical basis of photo-activated psoralen-induced DNA repair in the yeast Saccharomyces cerevisiae we have identified and cloned 10 pso mutants. Here, we describe the phenotypic characterization and molecular cloning of the pso10-1 mutant which is highly sensitive to photoactivated psoralens, UV(254) (nm) radiation and the alkylating agent methylmethane sulphonate. The pso10-1 mutant allele also confers a block in the mutagenic response to photoactivated psoralens and UV(254) (nm) radiation, and homoallelic diploids do not sporulate. Molecular cloning using a yeast genomic library, sequence analysis and genetic complementation experiments proved pso10-1 to be a mutant allele of gene MMS21 that encodes a SUMO ligase involved in the sumoylation of several DNA repair proteins. The ORF of pso10-1 contains a single nucleotide C-->T transition at position 758, which leads to a change in amino acid sequence from serine to phenylalanine [S253F]. Pso10-1p defines a leaky mutant phenotype of the essential MMS21 gene, and as member of the Smc5-Smc6 complex, still has some essential functions that allow survival of the mutant. DNA repair via translesion synthesis is severely impaired as the pso10-1 mutant allele confers severely blocked induced forward and reverse mutagenesis and shows epistatic interaction with a rev3Delta mutant allele. By identifying the allelism of PSO10 and MMS21 we demonstrate the need of a fully functional Smc5-Smc6 complex for a WT-like adequate repair of photoactivated psoralen-induced DNA damage in yeast.

  8. Microbial Community Structure and Arsenic Biogeochemistry in Two Arsenic-Impacted Aquifers in Bangladesh

    Directory of Open Access Journals (Sweden)

    Edwin T. Gnanaprakasam

    2017-11-01

    Full Text Available Long-term exposure to trace levels of arsenic (As in shallow groundwater used for drinking and irrigation puts millions of people at risk of chronic disease. Although microbial processes are implicated in mobilizing arsenic from aquifer sediments into groundwater, the precise mechanism remains ambiguous. The goal of this work was to target, for the first time, a comprehensive suite of state-of-the-art molecular techniques in order to better constrain the relationship between indigenous microbial communities and the iron and arsenic mineral phases present in sediments at two well-characterized arsenic-impacted aquifers in Bangladesh. At both sites, arsenate [As(V] was the major species of As present in sediments at depths with low aqueous As concentrations, while most sediment As was arsenite [As(III] at depths with elevated aqueous As concentrations. This is consistent with a role for the microbial As(V reduction in mobilizing arsenic. 16S rRNA gene analysis indicates that the arsenic-rich sediments were colonized by diverse bacterial communities implicated in both dissimilatory Fe(III and As(V reduction, while the correlation analyses involved phylogenetic groups not normally associated with As mobilization. Findings suggest that direct As redox transformations are central to arsenic fate and transport and that there is a residual reactive pool of both As(V and Fe(III in deeper sediments that could be released by microbial respiration in response to hydrologic perturbation, such as increased groundwater pumping that introduces reactive organic carbon to depth.

  9. Unraveling the mechanism of neuroprotection of curcumin in arsenic induced cholinergic dysfunctions in rats

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Pranay [CSIR-Indian Institute of Toxicology Research, Post Box 80, MG Marg, Lucknow 226 001 (India); Yadav, Rajesh S. [CSIR-Indian Institute of Toxicology Research, Post Box 80, MG Marg, Lucknow 226 001 (India); Department of Crimnology and Forensic Science, Harisingh Gour University, Sagar 470 003 (India); Chandravanshi, Lalit P.; Shukla, Rajendra K.; Dhuriya, Yogesh K.; Chauhan, Lalit K.S. [CSIR-Indian Institute of Toxicology Research, Post Box 80, MG Marg, Lucknow 226 001 (India); Dwivedi, Hari N. [Babu Banarasi Das University, BBD City, Faizabad Road, Lucknow 227 015 (India); Pant, Aditiya B. [CSIR-Indian Institute of Toxicology Research, Post Box 80, MG Marg, Lucknow 226 001 (India); Khanna, Vinay K., E-mail: vkkhanna1@gmail.com [CSIR-Indian Institute of Toxicology Research, Post Box 80, MG Marg, Lucknow 226 001 (India)

    2014-09-15

    Earlier, we found that arsenic induced cholinergic deficits in rat brain could be protected by curcumin. In continuation to this, the present study is focused to unravel the molecular mechanisms associated with the protective efficacy of curcumin in arsenic induced cholinergic deficits. Exposure to arsenic (20 mg/kg body weight, p.o) for 28 days in rats resulted to decrease the expression of CHRM2 receptor gene associated with mitochondrial dysfunctions as evident by decrease in the mitochondrial membrane potential, activity of mitochondrial complexes and enhanced apoptosis both in the frontal cortex and hippocampus in comparison to controls. The ultrastructural images of arsenic exposed rats, assessed by transmission electron microscope, exhibited loss of myelin sheath and distorted cristae in the mitochondria both in the frontal cortex and hippocampus as compared to controls. Simultaneous treatment with arsenic (20 mg/kg body weight, p.o) and curcumin (100 mg/kg body weight, p.o) for 28 days in rats was found to protect arsenic induced changes in the mitochondrial membrane potential and activity of mitochondrial complexes both in frontal cortex and hippocampus. Alterations in the expression of pro- and anti-apoptotic proteins and ultrastructural damage in the frontal cortex and hippocampus following arsenic exposure were also protected in rats simultaneously treated with arsenic and curcumin. The data of the present study reveal that curcumin could protect arsenic induced cholinergic deficits by modulating the expression of pro- and anti-apoptotic proteins in the brain. More interestingly, arsenic induced functional and ultrastructural changes in the brain mitochondria were also protected by curcumin. - Highlights: • Neuroprotective mechanism of curcumin in arsenic induced cholinergic deficits studied • Curcumin protected arsenic induced enhanced expression of stress markers in rat brain • Arsenic compromised mitochondrial electron transport chain protected

  10. Mismatch repair genes Mlh1 and Mlh3 modify CAG instability in Huntington's disease mice: genome-wide and candidate approaches.

    Directory of Open Access Journals (Sweden)

    Ricardo Mouro Pinto

    2013-10-01

    Full Text Available The Huntington's disease gene (HTT CAG repeat mutation undergoes somatic expansion that correlates with pathogenesis. Modifiers of somatic expansion may therefore provide routes for therapies targeting the underlying mutation, an approach that is likely applicable to other trinucleotide repeat diseases. Huntington's disease Hdh(Q111 mice exhibit higher levels of somatic HTT CAG expansion on a C57BL/6 genetic background (B6.Hdh(Q111 than on a 129 background (129.Hdh(Q111 . Linkage mapping in (B6x129.Hdh(Q111 F2 intercross animals identified a single quantitative trait locus underlying the strain-specific difference in expansion in the striatum, implicating mismatch repair (MMR gene Mlh1 as the most likely candidate modifier. Crossing B6.Hdh(Q111 mice onto an Mlh1 null background demonstrated that Mlh1 is essential for somatic CAG expansions and that it is an enhancer of nuclear huntingtin accumulation in striatal neurons. Hdh(Q111 somatic expansion was also abolished in mice deficient in the Mlh3 gene, implicating MutLγ (MLH1-MLH3 complex as a key driver of somatic expansion. Strikingly, Mlh1 and Mlh3 genes encoding MMR effector proteins were as critical to somatic expansion as Msh2 and Msh3 genes encoding DNA mismatch recognition complex MutSβ (MSH2-MSH3. The Mlh1 locus is highly polymorphic between B6 and 129 strains. While we were unable to detect any difference in base-base mismatch or short slipped-repeat repair activity between B6 and 129 MLH1 variants, repair efficiency was MLH1 dose-dependent. MLH1 mRNA and protein levels were significantly decreased in 129 mice compared to B6 mice, consistent with a dose-sensitive MLH1-dependent DNA repair mechanism underlying the somatic expansion difference between these strains. Together, these data identify Mlh1 and Mlh3 as novel critical genetic modifiers of HTT CAG instability, point to Mlh1 genetic variation as the likely source of the instability difference in B6 and 129 strains and suggest

  11. Deoxyribonucleic acid repair gene X-ray repair cross-complementing group 1 polymorphisms and non-carcinogenic disease risk in different populations: A meta-analysis.

    Science.gov (United States)

    Larijani, Bagher; Asl, Javad Mohammadi; Keshtkar, Abbas; Saki, Najmaldin; Larijani, Fatemeh Ardeshir; Rahim, Fakher

    2013-10-01

    This study aims to assess a meta-analysis of the association of X-ray repair cross-complementing group 1 (XRCC1) polymorphisms with the risk of various non-carcinogenic diseases in different population. This meta-analysis was performed by critically reviewing reveals 38 studies involving 10043 cases and 11037 controls. Among all the eligible studies, 14 focused on Arg194Trp polymorphism, 33 described the Arg399Gln and three articles investigated on Arg280His. Populations were divided into three different ethnic subgroups include Caucasians, Asians and other (Turkish and Iranian). Pooled results showed no correlation between Arg194Trp and non-carcinogenic disease. There was only weak relation in the recessive (odds ratio [OR] =1.11, 95% confidence interval [CI]: 0.86-1.44) model in Asian population and dominant (OR = 1.04, 95% CI: 0.66-1.63) model of other populations. In Arg399Gln polymorphism, there was no relation with diseases of interest generally. In the pooled analysis, there were weak relation in the dominant (OR = 1.08, 95% CI: 0.86-1.35) model of Asian population and quite well-correlation with recessive (OR = 1.49, 95% CI: 1.19-1.88), dominant (OR = 1.23, 95% CI: 0.94-1.62), and additive (OR = 1.23, 95% CI: 0.94-1.62) models of other subgroup. For Arg280His, there was a weak relation only in the dominant model (OR = 1.06, 95% CI: 0.74-1.51). The present meta-analysis correspondingly shows that Arg399Gln variant to be associated with increased non-carcinogenic diseases risk through dominant and recessive modes among Iranian and Turkish population. It also suggests a trend of dominant and recessive effect of Arg280His variant in all population and its possible protective effect on non-carcinogenic diseases.

  12. Arsenic and diabetes: Current perspectives

    OpenAIRE

    Chun Fa Huang; Ya Wen Chen; Ching Yao Yang; Keh Sung Tsai; Rong Sen Yang; Shing Hwa Liu

    2011-01-01

    Arsenic is a naturally occurring toxic metalloid of global concern. Many studies have indicated a dose–response relationship between accumulative arsenic exposure and the prevalence of diabetes mellitus (DM) in arseniasis-endemic areas in Taiwan and Bangladesh, where arsenic exposure occurs through drinking water. Epidemiological researches have suggested that the characteristics of arsenic-induced DM observed in arseniasis-endemic areas in Taiwan and Mexico are similar to those of non-insuli...

  13. International congress on DNA damage and repair: Book of abstracts

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    This document contains the abstracts of 105 papers presented at the Congress. Topics covered include the Escherichia coli nucleotide excision repair system, DNA repair in malignant transformations, defective DNA repair, and gene regulation. (TEM)

  14. EGFR exon 19 in-frame deletion and polymorphisms of DNA repair genes in never-smoking female lung adenocarcinoma patients.

    Science.gov (United States)

    Yang, Shi-Yi; Yang, Tsung-Ying; Li, Yao-Jen; Chen, Kun-Chieh; Liao, Kuo-Meng; Hsu, Kuo-Hsuan; Tsai, Chi-Ren; Chen, Chih-Yi; Hsu, Chung-Ping; Hsia, Jiun-Yi; Chuang, Cheng-Yen; Tsai, Ying-Huang; Chen, Kuan-Yu; Huang, Ming-Shyan; Su, Wu-Chou; Chen, Yuh-Min; Hsiung, Chao A; Shen, Chen-Yang; Chang, Gee-Chen; Yang, Pan-Chyr; Chen, Chien-Jen

    2013-01-15

    We explored potential associations between genetic polymorphisms in genes related to DNA repair and detoxification metabolism and epidermal growth factor receptor (EGFR) mutations in a cohort of 410 never-smoking patients with lung adenocarcinoma. Multivariate-adjusted odds ratios (aORs) and corresponding 95% confidence intervals (CI) of EGFR mutation status in association with the genotypes of DNA repair and detoxification metabolism genes were evaluated using logistic regression analysis. We found an association between in-frame deletion in EGFR exon 19 and a single nucleotide polymorphism (SNP) rs1800566C/T located in NQO1 (aOR, 2.2 with 95% CI, 1.0-4.8) in female never-smokers. The SNP rs744154C/G in ERCC4 was also associated with the EGFR exon 19 in-frame deletion both in never-smokers (aOR, 1.7 with 95% CI, 1.0-3.0) and female never-smokers (aOR, 1.9 with 95% CI, 1.0-3.6). Although the association was marginally significant in multivariate logistic regression analysis, the A/A genotype of rs1047840 in EXO1 was associated with a 7.6-fold increase in the occurrence of the EGFR exon 19 in-frame deletion in female never-smokers. Moreover, risk alleles in NQO1, ERCC4 and EXO1 were associated with an increasing aOR of the EGFR exon 19 in-frame deletion both in never-smokers (p = 0.007 for trend) and female never-smokers (p = 0.002 for trend). Our findings suggest that the in-frame deletion in EGFR exon 19 is associated with polymorphisms in DNA repair and detoxification metabolism genes in never-smoking lung adenocarcinoma patients, especially in females. Copyright © 2012 UICC.

  15. Hypospadias repair

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003000.htm Hypospadias repair To use the sharing features on this page, please enable JavaScript. Hypospadias repair is surgery to correct a defect in ...

  16. Arsenic exposure at low-to-moderate levels and skin lesions, arsenic metabolism, neurological functions, and biomarkers for respiratory and cardiovascular diseases: review of recent findings from the Health Effects of Arsenic Longitudinal Study (HEALS) in Bangladesh.

    Science.gov (United States)

    Chen, Yu; Parvez, Faruque; Gamble, Mary; Islam, Tariqul; Ahmed, Alauddin; Argos, Maria; Graziano, Joseph H; Ahsan, Habibul

    2009-09-01

    The contamination of groundwater by arsenic in Bangladesh is a major public health concern affecting 35-75 million people. Although it is evident that high levels (>300 microg/L) of arsenic exposure from drinking water are related to adverse health outcomes, health effects of arsenic exposure at low-to-moderate levels (10-300 microg/L) are not well understood. We established the Health Effects of Arsenic Longitudinal Study (HEALS) with more than 20,000 men and women in Araihazar, Bangladesh, to prospectively investigate the health effects of arsenic predominantly at low-to-moderate levels (0.1 to 864 microg/L, mean 99 microg/L) of arsenic exposure. Findings to date suggest adverse effects of low-to-moderate levels of arsenic exposure on the risk of pre-malignant skin lesions, high blood pressure, neurological dysfunctions, and all-cause and chronic disease mortality. In addition, the data also indicate that the risk of skin lesion due to arsenic exposure is modifiable by nutritional factors, such as folate and selenium status, lifestyle factors, including cigarette smoking and body mass index, and genetic polymorphisms in genes related to arsenic metabolism. The analyses of biomarkers for respiratory and cardiovascular functions support that there may be adverse effects of arsenic on these outcomes and call for confirmation in large studies. A unique strength of the HEALS is the availability of outcome data collected prospectively and data on detailed individual-level arsenic exposure estimated using water, blood and repeated urine samples. Future prospective analyses of clinical endpoints and related host susceptibility will enhance our knowledge on the health effects of low-to-moderate levels of arsenic exposure, elucidate disease mechanisms, and give directions for prevention.

  17. Arsenic Exposure at Low-to-Moderate Levels and Skin Lesions, Arsenic Metabolism, Neurological Functions, and Biomarkers for Respiratory and Cardiovascular Diseases: Review of Recent Findings from the Health Effects of Arsenic Longitudinal Study (HEALS) in Bangladesh

    Science.gov (United States)

    Chen, Yu; Parvez, Faruque; Gamble, Mary; Islam, Tariqul; Ahmed, Alauddin; Argos, Maria; Graziano, Joseph H.; Ahsan, Habibul

    2012-01-01

    The contamination of groundwater by arsenic in Bangladesh is a major public health concern affecting 35–75 million people. Although it is evident that high levels (> 300 µg/L) of arsenic exposure from drinking water are related to adverse health outcomes, health effects of arsenic exposure at low-to-moderate levels (10–300 µg/L) are not well understood. We established the Health Effects of Arsenic Longitudinal Study (HEALS) with more than 20,000 men and women in Araihazar, Bangladesh, to prospectively investigate the health effects of arsenic predominately at low-to-moderate levels (0.1 to 864 µg/L, mean 99 µg/L) of arsenic exposure. Findings to date suggest adverse effects of low-to-moderate levels of arsenic exposure on the risk of pre-malignant skin lesions, high blood pressure, neurological dysfunctions, and all-cause and chronic disease mortality. In addition, the data also indicate that the risk of skin lesion due to arsenic exposure is modifiable by nutritional factors, such as folate and selenium status, lifestyle factors, including cigarette smoking and body mass index, and genetic polymorphisms in genes related to arsenic metabolism. The analyses of biomarkers for respiratory and cardiovascular functions support that there may be adverse effects of arsenic on these outcomes and call for confirmation in large studies. A unique strength of the HEALS is the availability of outcome data collected prospectively and data on detailed individual-level arsenic exposure estimated using water, blood and repeated urine samples. Future prospective analyses of clinical endpoints and related host susceptibility will enhance our knowledge on the health effects of low-to-moderate levels of arsenic exposure, elucidate disease mechanisms, and give directions for prevention. PMID:19371619

  18. Methylenetetrahydrofolate reductase genotype in diffuse large B-cell lymphomas with and without hypermethylation of the DNA repair gene O6-methylguanine DNA methyltransferase.

    Science.gov (United States)

    Toffoli, G; Rossi, D; Gaidano, G; Cecchin, E; Boiocchi, M; Carbone, A

    2003-01-01

    C677T and A1298C methylenetetrahydrofolate reductase (MTHFR) polymorphisms have been suggested to affect susceptibility to malignant lymphoma, possibly by altering DNA methylation. The DNA repair gene O6-methylguanine DNA methyltransferase (MGMT) is transcriptionally silenced by promoter hypermethylation in diffuse large B-cell lymphomas (DLBCL). We analyzed the MTHFR677 and MTHFR1298 genotypes in 111 DLBCL patients and 465 controls. No significant difference in the frequency of MTHFR polymorphisms between patients and controls and no significant association between MTHFR677 or MTHFR1298 genotypes and methylation of MGMT promoter were observed. These results indicate that MTHFR variants are not related to DLBCL development and MGMT hypermethylation.

  19. Café-au-lait macules and pediatric malignancy caused by biallelic mutations in the DNA mismatch repair (MMR) gene PMS2.

    Science.gov (United States)

    Jackson, Carl-Christian; Holter, Spring; Pollett, Aaron; Clendenning, Mark; Chou, Shirley; Senter, Leigha; Ramphal, Raveena; Gallinger, Steven; Boycott, Kym

    2008-06-01

    A 14-year-old male presented with a T4 sigmoid adenocarcinoma, lait macules. Family history was not suggestive of a dominant hereditary form of colorectal cancer. Evaluation of the tumor revealed abnormal immunohistochemical staining of the PMS2 protein and high frequency microsatellite instability. Germline analysis identified biallelic PMS2 missense mutations. A new cancer syndrome caused by biallelic mutations in the mismatch repair genes, including PMS2, is now emerging and is characterized by café-au-lait macules, colonic polyps and a distinctive tumor spectrum. (c) 2007 Wiley-Liss, Inc.

  20. Arsenic: The Silent Killer

    Energy Technology Data Exchange (ETDEWEB)

    Foster, Andrea (USGS)

    2006-02-28

    Andrea Foster uses x-rays to determine the forms of potentially toxic elements in environmentally-important matrices such as water, sediments, plants, and microorganisms. In this free public lecture, Foster will discuss her research on arsenic, which is called the silent killer because dissolved in water, it is colorless, odorless, and tasteless, yet consumption of relatively small doses of this element in its most toxic forms can cause rapid and violent death. Arsenic is a well-known poison, and has been used as such since ancient times. Less well known is the fact that much lower doses of the element, consumed over years, can lead to a variety of skin and internal cancers that can also be fatal. Currently, what has been called the largest mass poisoning in history is occurring in Bangladesh, where most people are by necessity drinking ground water that is contaminated with arsenic far in excess of the maximum amounts determined to be safe by the World Health Organization. This presentation will review the long and complicated history with arsenic, describe how x-rays have helped explain the high yet spatially variable arsenic concentrations in Bangladesh, discuss the ways in which land use in Bangladesh may be exacerbating the problem, and summarize the impact of this silent killer on drinking water systems worldwide.

  1. Correlation of Breastmilk Arsenic With Maternal, Infant Urinary Arsenic and Drinking Water Arsenic in an Arsenic Affected Area of Bangladesh

    Science.gov (United States)

    Alauddin, M.; Islam, M. R.; Milton, A. H.; Alauddin, S. T.; Mouly, T.; Behri, E.; Ayesha, A.; Akter, S.; Islam, M. M.

    2016-12-01

    About 97% of population in Bangladesh depend on groundwater as the principle source of drinking water and this water is highly contaminated with inorganic arsenic. Consumption of arsenic contaminated drinking water by pregnant women raises the prospect of early life exposure to inorganic arsenic for newborn which may be lead to adverse health effect in later life. This work was carried out in parts of Gopalganj district in Bangladesh, a region affected by arsenic contamination in groundwater. The objective of the work was to assess potential early life exposure to arsenic for infants through breastfeeding by mothers who were drinking water with arsenic levels ranging from 100 to 300 µg/l. A cohort of 30 mother-baby pairs were selected for the current study. Breastmilk samples from mothers, urine samples from each pair of subjects at 1, 6 and 9 month age of infant were collected and total arsenic were determined in these samples. In addition speciation of urinary arsenic and metabolites were carried out in 12 mother-baby pairs. Median level for breastmilk arsenic were 0.50 µg/l. Urinary arsenic of infants did not correlate with breastmilk arsenic with progressing age of infants. Maternal and infant urinary total arsenic at 1 month age of infant showed some positive correlation (r = 0.39). In infant urine major metabolite were dimethyl arsenic acid (DMA) (approximately 70%) indicating good methylating capacity for infants at 1 and 6 months of age. In conclusion, infants were not exposed to arsenic through breastfeeding even though mothers were exposed to significant levels of arsenic through drinking water.

  2. Developmental defects and male sterility in mice lacking the ubiquitin-like DNA repair gene mHR23B.

    NARCIS (Netherlands)

    J.M.Y. Ng (Jessica); H. Vrieling (Harry); K. Sugasawa (Kaoru); M.P. Ooms (Marja); J.A. Grootegoed (Anton); J.T.M. Vreeburg (Jan); P. Visser (Pim); R.B. Beems (Rudolf); T.G.M.F. Gorgels (Theo); F. Hanaoka (Fumio); J.H.J. Hoeijmakers (Jan); G.T.J. van der Horst (Gijsbertus)

    2002-01-01

    textabstractmHR23B encodes one of the two mammalian homologs of Saccharomyces cerevisiae RAD23, a ubiquitin-like fusion protein involved in nucleotide excision repair (NER). Part of mHR23B is complexed with the XPC protein, and this heterodimer functions as the main damage detector and initiator of

  3. Completion of meiosis in male zebrafish (Danio rerio) despite lack of DNA mismatch repair gene mlh1.

    NARCIS (Netherlands)

    Leal, M.C.; Feitsma, H.; Cuppen, E.; Franca, L.R.; Schulz, R.W.

    2008-01-01

    Mlh1 is a member of DNA mismatch repair (MMR) machinery and is also essential for the stabilization of crossovers during the first meiotic division. Recently, we have shown that zebrafish mlh1 mutant males are completely infertile because of a block in metaphase I, whereas females are fertile but

  4. Genome-wide gene expression analysis in cancer cells reveals 3D growth to affect ECM and processes associated with cell adhesion but not DNA repair.

    Directory of Open Access Journals (Sweden)

    Oliver Zschenker

    Full Text Available Cell morphology determines cell behavior, signal transduction, protein-protein interaction, and responsiveness to external stimuli. In cancer, these functions profoundly contribute to resistance mechanisms to radio- and chemotherapy. With regard to this aspect, this study compared the genome wide gene expression in exponentially growing cell lines from different tumor entities, lung carcinoma and squamous cell carcinoma, under more physiological three-dimensional (3D versus monolayer cell culture conditions. Whole genome cDNA microarray analysis was accomplished using the Affymetrix HG U133 Plus 2.0 gene chip. Significance analysis of microarray (SAM and t-test analysis revealed significant changes in gene expression profiles of 3D relative to 2D cell culture conditions. These changes affected the extracellular matrix and were mainly associated with biological processes like tissue development, cell adhesion, immune system and defense response in contrast to terms related to DNA repair, which lacked significant alterations. Selected genes were verified by semi-quantitative RT-PCR and Western blotting. Additionally, we show that 3D growth mediates a significant increase in tumor cell radio- and chemoresistance relative to 2D. Our findings show significant gene expression differences between 3D and 2D cell culture systems and indicate that cellular responsiveness to external stress such as ionizing radiation and chemotherapeutics is essentially influenced by differential expression of genes involved in the regulation of integrin signaling, cell shape and cell-cell contact.

  5. The role of base excision repair genes OGG1, APN1 and APN2 in benzo[a]pyrene-7,8-dione induced p53 mutagenesis.

    Science.gov (United States)

    Abedin, Zahidur; Louis-Juste, Melissa; Stangl, Melissa; Field, Jeffrey

    2013-01-20

    Lung cancer is primarily caused by exposure to tobacco smoke. Tobacco smoke contains numerous carcinogens, including polycyclic aromatic hydrocarbons (PAH). The most common PAH studied is benzo[a]pyrene (B[a]P). B[a]P is metabolically activated through multiple routes, one of which is catalyzed by aldo-keto reductase (AKR) to B[a]P-7,8-dione (BPQ). BPQ undergoes a futile redox cycle in the presence of NADPH to generate reactive oxygen species (ROS). ROS, in turn, damages DNA. Studies with a yeast p53 mutagenesis system found that the generation of ROS by PAH o-quinones may contribute to lung carcinogenesis because of similarities between the patterns (types of mutations) and spectra (location of mutations) and those seen in lung cancer. The patterns were dominated by G to T transversions, and the spectra in the experimental system have mutations at lung cancer hotspots. To address repair mechanisms that are responsible for BPQ induced damage we observed the effect of mutating two DNA repair genes OGG1 and APE1 (APN1 in yeast) and tested them in a yeast reporter system for p53 mutagenesis. There was an increase in both the mutant frequency and the number of G:C/T:A transversions in p53 treated with BPQ in ogg1 yeast but not in apn1 yeast. Knocking out APN2 increased mutagenesis in the apn1 cells. In addition, we did not find a strand bias on p53 treated with BPQ in ogg1 yeast. These studies suggest that Ogg1 is involved in repairing the oxidative damage caused by BPQ, Apn1 and Apn2 have redundant functions and that the stand bias seen in lung cancer may not be due to impaired repair of oxidative lesions. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Demethylation and alterations in the expression level of the cell cycle-related genes as possible mechanisms in arsenic trioxide-induced cell cycle arrest in human breast cancer cells.

    Science.gov (United States)

    Moghaddaskho, Farima; Eyvani, Haniyeh; Ghadami, Mohsen; Tavakkoly-Bazzaz, Javad; Alimoghaddam, Kamran; Ghavamzadeh, Ardeshir; Ghaffari, Seyed H

    2017-02-01

    Arsenic trioxide (As2O3) has been used clinically as an anti-tumor agent. Its mechanisms are mostly considered to be the induction of apoptosis and cell cycle arrest. However, the detailed molecular mechanisms of its anti-cancer action through cell cycle arrest are poorly known. Furthermore, As2O3 has been shown to be a potential DNA methylation inhibitor, inducing DNA hypomethylation. We hypothesize that As2O3 may affect the expression of cell cycle regulatory genes by interfering with DNA methylation patterns. To explore this, we examined promoter methylation status of 24 cell cycle genes in breast cancer cell lines and in a normal breast tissue sample by methylation-specific polymerase chain reaction and/or restriction enzyme-based methods. Gene expression level and cell cycle distribution were quantified by real-time polymerase chain reaction and flow cytometric analyses, respectively. Our methylation analysis indicates that only promoters of RBL1 (p107), RASSF1A, and cyclin D2 were aberrantly methylated in studied breast cancer cell lines. As2O3 induced CpG island demethylation in promoter regions of these genes and restores their expression correlated with DNA methyltransferase inhibition. As2O3 also induced alterations in messenger RNA expression of several cell cycle-related genes independent of demethylation. Flow cytometric analysis revealed that the cell cycle arrest induced by As2O3 varied depending on cell lines, MCF-7 at G1 phase and both MDA-MB-231 and MDA-MB-468 cells at G2/M phase. These changes at transcriptional level of the cell cycle genes by the molecular mechanisms dependent and independent of demethylation are likely to represent the mechanisms of cell cycle redistribution in breast cancer cells, in response to As2O3 treatment.

  7. The impact of polymorphisms in P-gp, DNA repair and folic acid metabolism genes in newly diagnosed multiple myeloma patients treated with thalidomide plus dexamethasone, with or without bortezomib

    OpenAIRE

    Lyzbicki, Barnaba

    2012-01-01

    The principle aim of this study was to investigate biological predictors of response and resistance to multiple myeloma treatment. Two hypothesis had been proposed as responsible of responsiveness: SNPs in DNA repair and Folate pathway, and P-gp dependent efflux. As a first objective, panel of SNPs in DNA repair and Folate pathway genes, were analyzed. It was a retrospective study in a group of 454, previously untreated, MM patients enrolled in a randomized phase III open-label study. Res...

  8. Environmental source of arsenic exposure.

    Science.gov (United States)

    Chung, Jin-Yong; Yu, Seung-Do; Hong, Young-Seoub

    2014-09-01

    Arsenic is a ubiquitous, naturally occurring metalloid that may be a significant risk factor for cancer after exposure to contaminated drinking water, cigarettes, foods, industry, occupational environment, and air. Among the various routes of arsenic exposure, drinking water is the largest source of arsenic poisoning worldwide. Arsenic exposure from ingested foods usually comes from food crops grown in arsenic-contaminated soil and/or irrigated with arsenic-contaminated water. According to a recent World Health Organization report, arsenic from contaminated water can be quickly and easily absorbed and depending on its metabolic form, may adversely affect human health. Recently, the US Food and Drug Administration regulations for metals found in cosmetics to protect consumers against contaminations deemed deleterious to health; some cosmetics were found to contain a variety of chemicals including heavy metals, which are sometimes used as preservatives. Moreover, developing countries tend to have a growing number of industrial factories that unfortunately, harm the environment, especially in cities where industrial and vehicle emissions, as well as household activities, cause serious air pollution. Air is also an important source of arsenic exposure in areas with industrial activity. The presence of arsenic in airborne particulate matter is considered a risk for certain diseases. Taken together, various potential pathways of arsenic exposure seem to affect humans adversely, and future efforts to reduce arsenic exposure caused by environmental factors should be made.

  9. Environmental Source of Arsenic Exposure

    Directory of Open Access Journals (Sweden)

    Jin-Yong Chung

    2014-09-01

    Full Text Available Arsenic is a ubiquitous, naturally occurring metalloid that may be a significant risk factor for cancer after exposure to contaminated drinking water, cigarettes, foods, industry, occupational environment, and air. Among the various routes of arsenic exposure, drinking water is the largest source of arsenic poisoning worldwide. Arsenic exposure from ingested foods usually comes from food crops grown in arsenic-contaminated soil and/or irrigated with arsenic-contaminated water. According to a recent World Health Organization report, arsenic from contaminated water can be quickly and easily absorbed and depending on its metabolic form, may adversely affect human health. Recently, the US Food and Drug Administration regulations for metals found in cosmetics to protect consumers against contaminations deemed deleterious to health; some cosmetics were found to contain a variety of chemicals including heavy metals, which are sometimes used as preservatives. Moreover, developing countries tend to have a growing number of industrial factories that unfortunately, harm the environment, especially in cities where industrial and vehicle emissions, as well as household activities, cause serious air pollution. Air is also an important source of arsenic exposure in areas with industrial activity. The presence of arsenic in airborne particulate matter is considered a risk for certain diseases. Taken together, various potential pathways of arsenic exposure seem to affect humans adversely, and future efforts to reduce arsenic exposure caused by environmental factors should be made.

  10. Associations of DNA-repair gene polymorphisms with a genetic susceptibility to ionizing radiation in residents of areas with high radon (222Rn) concentration.

    Science.gov (United States)

    Sinitsky, Maxim Y; Larionov, Aleksey V; Asanov, Maxim A; Druzhinin, Vladimir G

    2015-06-01

    To investigate the individual radiosensitivity of the human genome in long-term residents of areas with high radon concentration. The materials used for this investigation were venous blood samples extracted from children living in the boarding school of Tashtagol (Kemerovo Region, Russia). Cytogenetic damage assessment was performed using the cytokinesis-block micronucleus assay (CBMN) on peripheral blood lymphocytes. PCR, gel electrophoresis and product detection using a transilluminator were used to determine polymorphisms in the genes ADPRT (rs 1136410), hOGG1 (rs 1052133), NBS1 (rs 1805794), XRCC1 (rs 25487), XpC (rs 2228001), XpD (rs 13181), and XpG (rs 17655). Statistical analysis was performed using nonparametric methods. To ensure accurate results, FDR-correction for multiple comparisons was performed. We discovered a significant increase in the frequency of binucleated lymphocytes with micronuclei (MN) in carriers of the His/His genotype of the XpG gene Asp1104His polymorphism in comparison to heterozygous and homozygous carriers of the Asp allele. In addition, the Ala/Ala genotype for the ADPRT gene Val762Ala polymorphism and the Glu/Gln genotype for the NBS1 gene Glu185Gln polymorphism were associated with the elevated frequency of binucleated lymphocytes with nucleoplasmic bridges (NPB). As a result of this study, the elevated frequency of cytogenetic damage in people with particular DNA-repair gene polymorphisms in response to chronic exposure to radon was demonstrated. It was shown that the genes and corresponding polymorphisms (the XpG gene Asp1104His polymorphism, the ADPRT gene Val762Ala polymorphism and the NBS1 gene Glu185Gln polymorphism) can be used as molecular genetic markers of increased individual radiosensitivity in long-term residents of areas with high concentrations of radon.

  11. Arsenic and Selenium

    Science.gov (United States)

    Plant, J. A.; Kinniburgh, D. G.; Smedley, P. L.; Fordyce, F. M.; Klinck, B. A.

    2003-12-01

    Arsenic (As) and selenium (Se) have become increasingly important in environmental geochemistry because of their significance to human health. Their concentrations vary markedly in the environment, partly in relation to geology and partly as a result of human activity. Some of the contamination evident today probably dates back to the first settled civilizations which used metals.Arsenic is in group 15 of the periodic table (Table 1) and is usually described as a metalloid. It has only one stable isotope, 75As. It can exist in the -III, -I, 0, III, and V oxidation states (Table 2).

  12. ARSENIC SPECIATION ANALYSIS IN HUMAN SALIVA

    Science.gov (United States)

    Background: Determination of arsenic species in human saliva is potentially useful for biomonitoring of human exposure to arsenic and for studying arsenic metabolism. However, there is no report on the speciation analysis of arsenic in saliva. Methods: Arsenic species in saliva ...

  13. Thyroid nodules, polymorphic variants in DNA repair and RET-related genes, and interaction with ionizing radiation exposure from nuclear tests in Kazakhstan.

    Science.gov (United States)

    Sigurdson, Alice J; Land, Charles E; Bhatti, Parveen; Pineda, Marbin; Brenner, Alina; Carr, Zhanat; Gusev, Boris I; Zhumadilov, Zhaxibay; Simon, Steven L; Bouville, Andre; Rutter, Joni L; Ron, Elaine; Struewing, Jeffery P

    2009-01-01

    Risk factors for thyroid cancer remain largely unknown except for ionizing radiation exposure during childhood and a history of benign thyroid nodules. Because thyroid nodules are more common than thyroid cancers and are associated with thyroid cancer risk, we evaluated several polymorphisms potentially relevant to thyroid tumors and assessed interaction with ionizing radiation exposure to the thyroid gland. Thyroid nodules were detected in 1998 by ultrasound screening of 2997 persons who lived near the Semipalatinsk nuclear test site in Kazakhstan when they were children (1949-1962). Cases with thyroid nodules (n = 907) were frequency matched (1:1) to those without nodules by ethnicity (Kazakh or Russian), gender and age at screening. Thyroid gland radiation doses were estimated from fallout deposition patterns, residence history and diet. We analyzed 23 polymorphisms in 13 genes and assessed interaction with ionizing radiation exposure using likelihood ratio tests (LRT). Elevated thyroid nodule risks were associated with the minor alleles of RET S836S (rs1800862, P = 0.03) and GFRA1 -193C>G (rs not assigned, P = 0.05) and decreased risk with XRCC1 R194W (rs1799782, P trend = 0.03) and TGFB1 T263I (rs1800472, P = 0.009). Similar patterns of association were observed for a small number of papillary thyroid cancers (n = 25). Ionizing radiation exposure to the thyroid gland was associated with significantly increased risk of thyroid nodules (age and gender adjusted excess odds ratio/Gy = 0.30, 95% CI 0.05-0.56), with evidence for interaction by genotype found for XRCC1 R194W (LRT P value = 0.02). Polymorphisms in RET signaling, DNA repair and proliferation genes may be related to risk of thyroid nodules, consistent with some previous reports on thyroid cancer. Borderline support for gene-radiation interaction was found for a variant in XRCC1, a key base excision repair protein. Other pathways such as genes in double-strand break repair, apoptosis and genes related to

  14. Efficacy of arsenic filtration by Kanchan arsenic filter in Nepal.

    Science.gov (United States)

    Singh, Anjana; Smith, Linda S; Shrestha, Shreekrishna; Maden, Narendra

    2014-09-01

    Groundwater arsenic contamination has caused a significant public health burden in lowland regions of Nepal. For arsenic mitigation purposes, the Kanchan Arsenic Filter (KAF) was developed and validated for use in 2003 after pilot studies showed its effectiveness in removing arsenic. However, its efficacy in field conditions operating for a long period has been scarcely observed. In this study, we observe the efficacy of KAFs running over 6 months in highly arsenic-affected households in Nawalparasi district. We assessed pair-wise arsenic concentrations of 62 randomly selected household tubewells before filtration and after filtration via KAFs. Of 62 tubewells, 41 had influent arsenic concentration exceeding the Nepal drinking water quality standard value (50 μg/L). Of the 41 tubewells having unsafe arsenic levels, KAFs reduced arsenic concentration to the safe level for only 22 tubewells, an efficacy of 54%. In conclusion, we did not find significantly high efficacy of KAFs in reducing unsafe influent arsenic level to the safe level under the in situ field conditions.

  15. Construction of a modular arsenic resistance operon in E. coli and the production of arsenic nanoparticles

    Directory of Open Access Journals (Sweden)

    Matthew Charles Edmundson

    2015-10-01

    Full Text Available Arsenic is a widespread contaminant of both land and water around the world. Current methods of decontamination such as phytoremediation and chemical adsorbents can be resource and time intensive, and may not be suitable for some areas such as remote communities where cost and transportation are major issues. Bacterial decontamination, with strict controls preventing environmental release, may offer a cost-effective alternative or provide a financial incentive when used in combination with other remediation techniques. In this study we have produced E. coli strains containing arsenic resistance genes from a number of sources, overexpressing them and testing their effects on arsenic resistance. While the lab E. coli strain JM109 (the wild-type is resistant up to 20 mM sodium arsenate the strain containing our plasmid pEC20 is resistant up to 80 mM. When combined with our construct pArsRBCC arsenic-containing nanoparticles were observed at the cell surface; the elements of pEC20 and pArsRBCC were therefore combined in a modular construct, pArs, in order to evaluate the roles and synergistic effects of the components of the original plasmids in arsenic resistance and nanoparticle formation. We also investigated the use of introducing the lac operator in order to more tightly control expression from pArs. We demonstrate that our strains are able to reduce toxic forms of arsenic into stable, insoluble metallic As(0, providing one way to remove arsenate contamination, and which may also be of benefit for other heavy metals.

  16. Combined Effects of Scaffold Stiffening and Mechanical Preconditioning Cycles on Construct Biomechanics, Gene Expression, and Tendon Repair Biomechanics

    OpenAIRE

    Nirmalanandhan, Victor Sanjit; Juncosa-Melvin, Natalia; Shearn, Jason T.; Boivin, Gregory P; Galloway, Marc T.; Gooch, Cynthia; Bradica, Gino; Butler, David L.

    2009-01-01

    Our group has previously reported that in vitro mechanical stimulation of tissue-engineered tendon constructs significantly increases both construct stiffness and the biomechanical properties of the repair tissue after surgery. When optimized using response surface methodology, our results indicate that a mechanical stimulus with three components (2.4% strain, 3000 cycles/day, and one cycle repetition) produced the highest in vitro linear stiffness. Such positive correlations between construc...

  17. Bladder exstrophy repair

    Science.gov (United States)

    Bladder birth defect repair; Everted bladder repair; Exposed bladder repair; Repair of bladder exstrophy ... Bladder exstrophy repair involves two surgeries. The first surgery is to repair the bladder. The second one ...

  18. The DNA repair genes RAD54 and UNG1 are cell cycle regulated in budding yeast but MCB promoter elements have no essential role in the DNA damage response.

    Science.gov (United States)

    Johnston, L H; Johnson, A L

    1995-06-25

    The DNA repair genes RAD54 and UNG1 have MCB elements in their promoters and are shown to be cell cycle regulated. Their transcripts are coordinately expressed with RNR1, ribonucleotide reductase, a MCB-regulated gene known to be expressed in late G1. However, no evidence was obtained for a direct role of MCB elements in DNA repair. Of the proteins that bind and activate MCB elements, only mutations in SWI6 have a defect in DNA repair, showing significant sensitivity to methyl methane sulphonate. Furthermore, analysis of the CDC9 promoter indicates that MCB elements are not required for the induction of the gene by ultraviolet light irradiation. These promoter elements may not respond directly to DNA damage but may have a role in enhancing the induction response.

  19. Arsenic and diabetes: current perspectives.

    Science.gov (United States)

    Huang, Chun Fa; Chen, Ya Wen; Yang, Ching Yao; Tsai, Keh Sung; Yang, Rong Sen; Liu, Shing Hwa

    2011-09-01

    Arsenic is a naturally occurring toxic metalloid of global concern. Many studies have indicated a dose-response relationship between accumulative arsenic exposure and the prevalence of diabetes mellitus (DM) in arseniasis-endemic areas in Taiwan and Bangladesh, where arsenic exposure occurs through drinking water. Epidemiological researches have suggested that the characteristics of arsenic-induced DM observed in arseniasis-endemic areas in Taiwan and Mexico are similar to those of non-insulin-dependent DM (Type 2 DM). These studies analyzed the association between high and chronic exposure to inorganic arsenic in drinking water and the development of DM, but the effect of exposure to low to moderate levels of inorganic arsenic on the risk of DM is unclear. Navas-Acien et al. recently proposed that a positive association existed between total urine arsenic and the prevalence of Type 2 DM in people exposed to low to moderate levels of arsenic. However, the diabetogenic role played by arsenic is still debated upon. An increase in the prevalence of DM has been observed among residents of highly arsenic-contaminated areas, whereas the findings from community-based and occupational studies in low-arsenic-exposure areas have been inconsistent. Recently, a population-based cross-sectional study showed that the current findings did not support an association between arsenic exposure from drinking water at levels less than 300 μg/L and a significantly increased risk of DM. Moreover, although the precise mechanisms for the arsenic-induced diabetogenic effect are still largely undefined, recent in vitro experimental studies indicated that inorganic arsenic or its metabolites impair insulin-dependent glucose uptake or glucose-stimulated insulin secretion. Nevertheless, the dose, the form of arsenic used, and the experimental duration in the in vivo studies varied greatly, leading to conflicting results and ambiguous interpretation of these data with respect to human exposure

  20. Arsenic and diabetes: Current perspectives

    Directory of Open Access Journals (Sweden)

    Chun Fa Huang

    2011-09-01

    Full Text Available Arsenic is a naturally occurring toxic metalloid of global concern. Many studies have indicated a dose–response relationship between accumulative arsenic exposure and the prevalence of diabetes mellitus (DM in arseniasis-endemic areas in Taiwan and Bangladesh, where arsenic exposure occurs through drinking water. Epidemiological researches have suggested that the characteristics of arsenic-induced DM observed in arseniasis-endemic areas in Taiwan and Mexico are similar to those of non-insulin-dependent DM (Type 2 DM. These studies analyzed the association between high and chronic exposure to inorganic arsenic in drinking water and the development of DM, but the effect of exposure to low to moderate levels of inorganic arsenic on the risk of DM is unclear. Navas-Acien et al. recently proposed that a positive association existed between total urine arsenic and the prevalence of Type 2 DM in people exposed to low to moderate levels of arsenic. However, the diabetogenic role played by arsenic is still debated upon. An increase in the prevalence of DM has been observed among residents of highly arsenic-contaminated areas, whereas the findings from community-based and occupational studies in low-arsenic-exposure areas have been inconsistent. Recently, a population-based cross-sectional study showed that the current findings did not support an association between arsenic exposure from drinking water at levels less than 300 μg/L and a significantly increased risk of DM. Moreover, although the precise mechanisms for the arsenic-induced diabetogenic effect are still largely undefined, recent in vitro experimental studies indicated that inorganic arsenic or its metabolites impair insulin-dependent glucose uptake or glucose-stimulated insulin secretion. Nevertheless, the dose, the form of arsenic used, and the experimental duration in the in vivo studies varied greatly, leading to conflicting results and ambiguous interpretation of these data with

  1. Questions and Answers: Apple Juice and Arsenic

    Science.gov (United States)

    ... for You Consumers Questions & Answers: Apple Juice and Arsenic Share Tweet Linkedin Pin it More sharing options ... it Email Print July 15, 2013 What is arsenic? Arsenic is present in the environment as a ...

  2. Bacterial resistance to arsenic protects against protist killing.

    Science.gov (United States)

    Hao, Xiuli; Li, Xuanji; Pal, Chandan; Hobman, Jon; Larsson, D G Joakim; Saquib, Quaiser; Alwathnani, Hend A; Rosen, Barry P; Zhu, Yong-Guan; Rensing, Christopher

    2017-04-01

    Protists kill their bacterial prey using toxic metals such as copper. Here we hypothesize that the metalloid arsenic has a similar role. To test this hypothesis, we examined intracellular survival of Escherichia coli (E. coli) in the amoeba Dictyostelium discoideum (D. discoideum). Deletion of the E. coli ars operon led to significantly lower intracellular survival compared to wild type E. coli. This suggests that protists use arsenic to poison bacterial cells in the phagosome, similar to their use of copper. In response to copper and arsenic poisoning by protists, there is selection for acquisition of arsenic and copper resistance genes in the bacterial prey to avoid killing. In agreement with this hypothesis, both copper and arsenic resistance determinants are widespread in many bacterial taxa and environments, and they are often found together on plasmids. A role for heavy metals and arsenic in the ancient predator-prey relationship between protists and bacteria could explain the widespread presence of metal resistance determinants in pristine environments.

  3. Nrf2-mediated redox signaling in arsenic carcinogenesis: a review.

    Science.gov (United States)

    Sinha, Dona; Biswas, Jaydip; Bishayee, Anupam

    2013-02-01

    Arsenic is a ubiquitous toxic metalloid whose natural leaching from geogenic resources of earths crust into groundwater has become a dreadful health hazard to millions of people across the globe. Arsenic has been documented as a top most potent human carcinogen by Agency of Toxic Substances and Disease Registry. There have been a number of schools of opinions regarding the underlying mechanism of arsenic-induced carcinogenicity, but the theory of oxidative stress generated by arsenic has gained much importance. Imbalance in the cellular redox state and its associated complications have been closely associated with nuclear factor-erythroid 2-related factor 2 (Nrf2), a basic-leucine zipper transcription factor that activates the antioxidant responsive element and electrophilic responsive element, thereby upregulating the expression of a variety of downstream genes. This review has been framed on the lines of differential molecular responses of Nrf2 on arsenic exposure as well as the chemopreventive strategy which may be improvised to regulate Nrf2 in order to combat arsenic-induced oxidative stress and its long-term carcinogenic effect.

  4. Microarray analysis of DNA damage repair gene expression profiles in cervical cancer cells radioresistant to 252Cf neutron and X-rays

    Directory of Open Access Journals (Sweden)

    Yang Zhen-Zhou

    2010-02-01

    Full Text Available Abstract Background The aim of the study was to obtain stable radioresistant sub-lines from the human cervical cancer cell line HeLa by prolonged exposure to 252Cf neutron and X-rays. Radioresistance mechanisms were investigated in the resulting cells using microarray analysis of DNA damage repair genes. Methods HeLa cells were treated with fractionated 252Cf neutron and X-rays, with a cumulative dose of 75 Gy each, over 8 months, yielding the sub-lines HeLaNR and HeLaXR. Radioresistant characteristics were detected by clone formation assay, ultrastructural observations, cell doubling time, cell cycle distribution, and apoptosis assay. Gene expression patterns of the radioresistant sub-lines were studied through microarray analysis and verified by Western blotting and real-time PCR. Results The radioresistant sub-lines HeLaNR and HeLaXR were more radioresisitant to 252Cf neutron and X-rays than parental HeLa cells by detecting their radioresistant characteristics, respectively. Compared to HeLa cells, the expression of 24 genes was significantly altered by at least 2-fold in HeLaNR cells. Of these, 19 genes were up-regulated and 5 down-regulated. In HeLaXR cells, 41 genes were significantly altered by at least 2-fold; 38 genes were up-regulated and 3 down-regulated. Conclusions Chronic exposure of cells to ionizing radiation induces adaptive responses that enhance tolerance of ionizing radiation and allow investigations of cellular radioresistance mechanisms. The insights gained into the molecular mechanisms activated by these "radioresistance" genes will lead to new therapeutic targets for cervical cancer.

  5. A new aerobic chemolithoautotrophic arsenic oxidizing microorganism isolated from a high Andean watershed.

    Science.gov (United States)

    Anguita, Javiera M; Rojas, Claudia; Pastén, Pablo A; Vargas, Ignacio T

    2017-11-16

    Biological arsenic oxidation has been suggested as a key biogeochemical process that controls the mobilization and fate of this metalloid in aqueous environments. To the best of our knowledge, only four aerobic chemolithoautotrophic arsenite-oxidizing (CAO) bacteria have been shown to grow via direct arsenic oxidation and to have the essential genes for chemolithoautotrophic arsenite oxidation. In this study, a new CAO bacterium was isolated from a high Andean watershed evidencing natural dissolved arsenic attenuation. The bacterial isolate, designated TS-1, is closely related to the Ancylobacter genus, in the Alphaproteobacteria class. Results showed that TS-1 has genes for arsenite oxidation and carbon fixation. The dependence of bacterial growth from arsenite oxidation was demonstrated. In addition, a mathematical model was suggested and the kinetic parameters were obtained by simultaneously fitting the biomass growth, arsenite depletion curves, and arsenate production. This research increases the knowledge of chemolithoautotrophic arsenic oxidizing microorganisms and its potential role as a driver for natural arsenic attenuation.

  6. Removal of arsenic using reverse osmosis

    OpenAIRE

    Fauskrud, Marie

    2013-01-01

    Master's thesis in Water and Enviromental Technology Arsenic is an element that naturally occurs in rocks and sediments. In some areas, arsenic is released to ground water and can contaminate drinking water sources. Since arsenic is toxic in high doses and a carcinogen, the World Health Organisation (WHO) recommends arsenic levels lower than 10 μg/L in drinking water. This thesis describes the removal of arsenic in a reverse osmosis system. Arsenic is usually present in water in two oxi...

  7. Rural methods to mitigate arsenic contaminated water

    OpenAIRE

    Parajuli, Krishna

    2013-01-01

    Consumption of arsenic contaminated water is one of the burning issues in the rural world. Poor public awareness program about health effects of drinking arsenic contaminated water and the rural methods to mitigate this problem poses a great threat of arsenic poisoning many people of the rural world. In this thesis, arsenic removal efficiency and the working mechanism of four rural and economical arsenic mitigation technologies i.e. solar oxidation and reduction of arsenic (SORAS), Bucket tr...

  8. Clubfoot repair

    Science.gov (United States)

    ... Clubfoot release; Talipes equinovarus - repair; Tibialis anterior tendon transfer Patient ... of the foot. In: Herring JA, ed. Tachdjian's Pediatric Orthopaedics . 5th ed. Philadelphia, PA: Elsevier Saunders; 2014: ...

  9. Repair of Staphylococcus aureus-infected wound with gene-modified C3H10T1/2 cells expressing BPI-BD3 fusion antibiotic peptide

    Directory of Open Access Journals (Sweden)

    Xin-ran ZHANG

    2015-10-01

    Full Text Available Objective To study the antibacterial and tissue reparative effect of BPI-BD3 gene-modified mesenchymal stem cells in a mouse model of wound infection. Methods C3H10T1/2 cells were transfected with recombinant adenovirus vector pAdxsi-BPI-BD3, the expression of BPI-BD3 fusion protein was verified by RT-PCR and Western blotting. Excision wound with a diameter of 1cm was inoculated with Staphylococcus aureuswas made on the back of 30 mice. The mice were randomly divided into 3 groups (10 each. Mice in group T were injected with BPI-BD3 gene-modified C3H10T1/2 cells through caudal vein, those in group C were injected with unmodified C3H10T1/2 cells, and in group N were injected with PBS as control. The wound repair result was evaluated by estimation of the percentage of remaining wound area and the amount of wound bacteria under the scar, followed by observation of pathological changes. Inflammatory reactions of the wounds were assessed accordingly. Results The amount of bacteria under the scar was less in group T than in the other two groups (P<0.05. It was also found that the wound healing process was faster in group T than in group C and group N. Pathological observation showed that the inflammatory reaction in group T was also significantly milder than in the other two groups. Conclusion BPI-BD3 gene-modified mesenchymal stem cells may enhance wound repair by controlling infection and promoting tissue regeneration, thus it may be promising in clinical application. DOI: 10.11855/j.issn.0577-7402.2015.09.07

  10. Polymorphisms in base excision repair genes as colorectal cancer risk factors and modifiers of the effect of diets high in red meat

    Science.gov (United States)

    Brevik, Asgeir; Joshi, Amit D.; Corral, Román; Onland-Moret, N. Charlotte; Siegmund, Kimberly D.; Le Marchand, Loïc; Baron, John A.; Martinez, Maria Elena; Haile, Robert W.; Ahnen, Dennis J.; Sandler, Robert S.; Lance, Peter; Stern, Mariana C.

    2010-01-01

    Background A diet high in red meat is an established colorectal cancer (CRC) risk factor. Carcinogens generated during meat cooking have been implicated as causal agents, and can induce oxidative DNA damage, which elicits repair by the base excision repair (BER) pathway. Methods Using a family-based study we investigated the role of polymorphisms in four BER genes (APEX1 Gln51His, Asp148Glu; OGG1 Ser236Cys; PARP Val742Ala; XRCC1 Arg194Trp, Arg280His, Arg399Gln) as potential CRC risk factors and modifiers of the association between high-red meat or poultry diets and CRC risk. We tested for gene-environment interactions using case-only analyses (N = 577) and compared statistically significant results to those obtained using case-unaffected sibling comparisons (N = 307 sibships). Results Carriers of the APEX1 codon 51 Gln/His genotype had a reduced CRC risk compared to carriers of the Gln/Gln genotype (OR 0.15, 95% CI 0.03-0.69, p = 0.015). The association between higher red meat intake (>3 servings/week) and CRC was modified by the PARP Val762Ala SNP (case-only interaction p = 0.026). This SNP also modified the association between higher intake of high-temperature cooked red meat (case-only interaction p = 0.0009). Conclusions We report evidence that the BER pathway PARP gene modifies the association of diets high in red meat cooked at high temperatures with risk of CRC. Impact Our findings suggest a contribution to colorectal carcinogenesis of free radical damage as one of the possible harmful effects of a high-red meat diet. PMID:21037106

  11. Identification of a deletion in the mismatch repair gene, MSH2, using mouse-human cell hybrids monosomal for chromosome 2.

    Science.gov (United States)

    Pyatt, R E; Nakagawa, H; Hampel, H; Sedra, M; Fuchik, M B; Comeras, I; de la Chapelle, A; Prior, T W

    2003-03-01

    Hereditary non-polyposis colorectal cancer is characterized by mutations in one of the DNA mismatch repair genes, primarily MLH1, MSH2, or MSH6. We report here the identification of a genomic deletion of approximately 11.4 kb encompassing the first two exons of the MSH2 gene in two generations of an Ohio family. By Southern blot analysis, using a cDNA probe spanning the first seven exons of MSH2, an alteration in each of three different enzyme digests (including a unique 13-kb band on HindIII digests) was observed, which suggested the presence of a large alteration in the 5' region of this gene. Mouse-human cell hybrids from a mutation carrier were then generated which contained a single copy each of human chromosome 2 on which the MSH2 gene resides. Southern blots on DNA from the cell hybrids demonstrated the same, unique 13-kb band from one MSH2 allele, as seen in the diploid DNA. DNA from this same monosomal cell hybrid failed to amplify in polymerase chain reactions (PCRs) using primers to exons 1 and 2, demonstrating the deletion of these sequences in one MSH2 allele, and the breakpoints involving Alu repeats were identified by PCR amplification and sequence analysis. Copyright Blackwell Munksgaard, 2003

  12. Methylation Analysis of DNA Mismatch Repair Genes Using DNA Derived from the Peripheral Blood of Patients with Endometrial Cancer: Epimutation in Endometrial Carcinogenesis

    Directory of Open Access Journals (Sweden)

    Takashi Takeda

    2016-10-01

    Full Text Available Germline mutation of DNA mismatch repair (MMR genes is a cause of Lynch syndrome. Methylation of MutL homolog 1 (MLH1 and MutS homolog 2 (MSH2 has been detected in peripheral blood cells of patients with colorectal cancer. This methylation is referred to as epimutation. Methylation of these genes has not been studied in an unselected series of endometrial cancer cases. Therefore, we examined methylation of MLH1, MSH2, and MSH6 promoter regions of peripheral blood cells in 206 patients with endometrial cancer using a methylation-specific polymerase chain reaction (MSP. Germline mutation of MMR genes, microsatellite instability (MSI, and immunohistochemistry (IHC were also analyzed in each case with epimutation. MLH1 epimutation was detected in a single patient out of a total of 206 (0.49%—1 out of 58 (1.72% with an onset age of less than 50 years. The patient with MLH1 epimutation showed high level MSI (MSI-H, loss of MLH1 expression and had developed endometrial cancer at 46 years old, complicated with colorectal cancer. No case had epimutation of MSH2 or MSH6. The MLH1 epimutation detected in a patient with endometrial cancer may be a cause of endometrial carcinogenesis. This result indicates that it is important to check epimutation in patients with endometrial cancer without a germline mutation of MMR genes.

  13. Epigenetic Studies Point to DNA Replication/Repair Genes as a Basis for the Heritable Nature of Long Term Complications in Diabetes

    Directory of Open Access Journals (Sweden)

    Alexey A. Leontovich

    2016-01-01

    Full Text Available Metabolic memory (MM is defined as the persistence of diabetic (DM complications even after glycemic control is pharmacologically achieved. Using a zebrafish diabetic model that induces a MM state, we previously reported that, in this model, tissue dysfunction was of a heritable nature based on cell proliferation studies in limb tissue and this correlated with epigenetic DNA methylation changes that paralleled alterations in gene expression. In the current study, control, DM, and MM excised fin tissues were further analyzed by MeDIP sequencing and microarray techniques. Bioinformatics analysis of the data found that genes of the DNA replication/DNA metabolism process group (with upregulation of the apex1, mcm2, mcm4, orc3, lig1, and dnmt1 genes were altered in the DM state and these molecular changes continued into MM. Interestingly, DNA methylation changes could be found as far as 6–13 kb upstream of the transcription start site for these genes suggesting potential higher levels of epigenetic control. In conclusion, DNA methylation changes in members of the DNA replication/repair process group best explain the heritable nature of cell proliferation impairment found in the zebrafish DM/MM model. These results are consistent with human diabetic epigenetic studies and provide one explanation for the persistence of long term tissue complications as seen in diabetes.

  14. Evaluating the performance of clinical criteria for predicting mismatch repair gene mutations in Lynch syndrome: a comprehensive analysis of 3,671 families.

    Science.gov (United States)

    Steinke, Verena; Holzapfel, Stefanie; Loeffler, Markus; Holinski-Feder, Elke; Morak, Monika; Schackert, Hans K; Görgens, Heike; Pox, Christian; Royer-Pokora, Brigitte; von Knebel-Doeberitz, Magnus; Büttner, Reinhard; Propping, Peter; Engel, Christoph

    2014-07-01

    Carriers of mismatch repair (MMR) gene mutations have a high lifetime risk for colorectal and endometrial cancers, as well as other malignancies. As mutation analysis to detect these patients is expensive and time-consuming, clinical criteria and tumor-tissue analysis are widely used as pre-screening methods. The aim of our study was to evaluate the performance of commonly applied clinical criteria (the Amsterdam I and II Criteria, and the original and revised Bethesda Guidelines) and the results of tumor-tissue analysis in predicting MMR gene mutations. We analyzed 3,671 families from the German HNPCC Registry and divided them into nine mutually exclusive groups with different clinical criteria. A total of 680 families (18.5%) were found to have a pathogenic MMR gene mutation. Among all 1,284 families with microsatellite instability-high (MSI-H) colorectal cancer, the overall mutation detection rate was 53.0%. Mutation frequencies and their distribution between the four MMR genes differed significantly between clinical groups (p small-bowel cancer (p small-bowel cancer were clinically relevant predictors for Lynch syndrome. © 2013 UICC.

  15. Metallothionein blocks oxidative DNA damage induced by acute inorganic arsenic exposure

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Wei, E-mail: qu@niehs.nih.gov; Waalkes, Michael P.

    2015-02-01

    We studied how protein metallothionein (MT) impacts arsenic-induced oxidative DNA damage (ODD) using cells that poorly express MT (MT-I/II double knockout embryonic cells; called MT-null cells) and wild-type (WT) MT competent cells. Arsenic (as NaAsO{sub 2}) was less cytolethal over 24 h in WT cells (LC{sub 50} = 11.0 ± 1.3 μM; mean ± SEM) than in MT-null cells (LC{sub 50} = 5.6 ± 1.2 μM). ODD was measured by the immuno-spin trapping method. Arsenic (1 or 5 μM; 24 h) induced much less ODD in WT cells (121% and 141% of control, respectively) than in MT-null cells (202% and 260%). In WT cells arsenic caused concentration-dependent increases in MT expression (transcript and protein), and in the metal-responsive transcription factor-1 (MTF-1), which is required to induce the MT gene. In contrast, basal MT levels were not detectable in MT-null cells and unaltered by arsenic exposure. Transfection of MT-I gene into the MT-null cells markedly reduced arsenic-induced ODD levels. The transport genes, Abcc1 and Abcc2 were increased by arsenic in WT cells but either showed no or very limited increases in MT-null cells. Arsenic caused increases in oxidant stress defense genes HO-1 and GSTα2 in both WT and MT-null cells, but to much higher levels in WT cells. WT cells appear more adept at activating metal transport systems and oxidant response genes, although the role of MT in these responses is unclear. Overall, MT protects against arsenic-induced ODD in MT competent cells by potential sequestration of scavenging oxidant radicals and/or arsenic. - Highlights: • Metallothionein blocks arsenic toxicity. • Metallothionein reduces arsenic-induced DNA damage. • Metallothionein may bind arsenic or radicals produced by arsenic.

  16. Diverse arsenic- and iron-cycling microbial communities in arsenic-contaminated aquifers used for drinking water in Bangladesh.

    Science.gov (United States)

    Hassan, Zahid; Sultana, Munawar; van Breukelen, Boris M; Khan, Sirajul I; Röling, Wilfred F M

    2015-04-01

    Subsurface removal of arsenic by injection with oxygenated groundwater has been proposed as a viable technology for obtaining 'safe' drinking water in Bangladesh. While the oxidation of ferrous iron to solid ferric iron minerals, to which arsenic adsorbs, is assumed to be driven by abiotic reactions, metal-cycling microorganisms may potentially affect arsenic removal. A cultivation-independent survey covering 24 drinking water wells in several geographical regions in Bangladesh was conducted to obtain information on microbial community structure and diversity in general, and on specific functional groups capable of the oxidation or reduction of arsenic or iron. Each functional group, targeted by either group-specific 16S rRNA or functional gene amplification, occurred in at least 79% of investigated samples. Putative arsenate reducers and iron-oxidizing Gallionellaceae were present at low diversity, while more variation in potentially arsenite-oxidizing microorganisms and iron-reducing Desulfuromonadales was revealed within and between samples. Relations between community composition on the one hand and hydrochemistry on the other hand were in general not evident, apart from an impact of salinity on iron-cycling microorganisms. Our data suggest widespread potential for a positive contribution of arsenite and iron oxidizers to arsenic removal upon injection with oxygenated water, but also indicate a potential risk for arsenic re-mobilization by anaerobic arsenate and iron reducers once injection is halted. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Sulforaphane prevents pulmonary damage in response to inhaled arsenic by activating the Nrf2-defense response

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yi [Department of Environmental and Occupational Health, School of Public Health, China Medical University, Shenyang, Liaoning 110001 (China); Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, 1703 East Mabel Street, Tucson, AZ 85721 (United States); Tao, Shasha [Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, 1703 East Mabel Street, Tucson, AZ 85721 (United States); Lian, Fangru [Department of Pathology, University of Arizona, 1501 North Campbell Ave, Tucson, AZ 85724 (United States); Chau, Binh T. [Department of Cellular and Molecular Medicine, The University of Arizona, 1501 North Campbell Ave, Tucson, AZ 85724 (United States); Chen, Jie; Sun, Guifan [Department of Environmental and Occupational Health, School of Public Health, China Medical University, Shenyang, Liaoning 110001 (China); Fang, Deyu [Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611 (United States); Lantz, R. Clark [Department of Cellular and Molecular Medicine, The University of Arizona, 1501 North Campbell Ave, Tucson, AZ 85724 (United States); Arizona Cancer Center, University of Arizona, 1515 North Campbell Avenue, Tucson, AZ 85724 (United States); Zhang, Donna D., E-mail: dzhang@pharmacy.arizona.edu [Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, 1703 East Mabel Street, Tucson, AZ 85721 (United States); Arizona Cancer Center, University of Arizona, 1515 North Campbell Avenue, Tucson, AZ 85724 (United States)

    2012-12-15

    Exposure to arsenic is associated with an increased risk of lung disease. Novel strategies are needed to reduce the adverse health effects associated with arsenic exposure in the lung. Nrf2, a transcription factor that mediates an adaptive cellular defense response, is effective in detoxifying environmental insults and prevents a broad spectrum of diseases induced by environmental exposure to harmful substances. In this report, we tested whether Nrf2 activation protects mice from arsenic-induced toxicity. We used an in vivo arsenic inhalation model that is highly relevant to low environmental human exposure to arsenic-containing dusts. Two-week exposure to arsenic-containing dust resulted in pathological alterations, oxidative DNA damage, and mild apoptotic cell death in the lung; all of which were blocked by sulforaphane (SF) in an Nrf2-dependent manner. Mechanistically, SF-mediated activation of Nrf2 alleviated inflammatory responses by modulating cytokine production. This study provides strong evidence that dietary intervention targeting Nrf2 activation is a feasible approach to reduce adverse health effects associated with arsenic exposure. -- Highlights: ► Exposed to arsenic particles and/or SF have elevated Nrf2 and its target genes. ► Sulforaphane prevents pathological alterations, oxidative damage and cell death. ► Sulforaphane alleviates infiltration of inflammatory cells into the lungs. ► Sulforaphane suppresses arsenic-induced proinflammatory cytokine production.

  18. Environmentally relevant dose of arsenic interferes in functions of human monocytes derived dendritic cells.

    Science.gov (United States)

    Bahari, Abbas; Salmani, Vahid

    2017-06-05

    Arsenic is a major environmental pollutant and highly hazardous toxin to human health, which well established as carcinogen and immune deregulatory properties. Dendritic cells (DCs) have a pivotal role in cell-mediated immunity for T-cell activation and antigen presentation. In this study, T cell activation, some key functional genes expression, cell stability and phagocytosis capacity of human monocytes derived DCs (MDDCs) were analyzed after in vitro exposure to very low dose of arsenic for 12 and 24h. Arsenic decreased continually phagocytosis capacity of MDDCs. Furthermore, down-regulation of the cell-surface expression of the co-stimulatory molecule CD40 after 24h post treatment with arsenic, confirmed arsenic interferers in the phagocytosis process. Pro inflammatory cytokines, IL1β and TNFα were more expressed in arsenic-treated MDDCs while IL6 transiently was down regulated. In general, our novel findings here strongly suggest that low level of arsenic dysregulates four fundamental immune processes of DCs. Mechanistically; this could explain the observed immunodeficiency activity of Arsenic, and give direction for comprehension the pathogenesis of Arsenic-induced diseases. Copyright © 2017. Published by Elsevier B.V.

  19. DNA repair genes RAD52 and SRS2, a cell wall synthesis regulator gene SMI1, and the membrane sterol synthesis scaffold gene ERG28 are important in efficient Agrobacterium-mediated yeast transformation with chromosomal T-DNA.

    Science.gov (United States)

    Ohmine, Yuta; Satoh, Yukari; Kiyokawa, Kazuya; Yamamoto, Shinji; Moriguchi, Kazuki; Suzuki, Katsunori

    2016-04-02

    Plant pathogenic Agrobacterium strains can transfer T-DNA regions of their Ti plasmids to a broad range of eukaryotic hosts, including fungi, in vitro. In the recent decade, the yeast Saccharomyces cerevisiae is used as a model host to reveal important host proteins for the Agrobacterium-mediated transformation (AMT). Further investigation is required to understand the fundamental mechanism of AMT, including interaction at the cell surface, to expand the host range, and to develop new tools. In this study, we screened a yeast mutant library for low AMT mutant strains by advantage of a chromosome type T-DNA, which transfer is efficient and independent on integration into host chromosome. By the mutant screening, we identified four mutant strains (srs2Δ, rad52Δ, smi1Δ and erg28Δ), which showed considerably low AMT efficiency. Structural analysis of T-DNA product replicons in AMT colonies of mutants lacking each of the two DNA repair genes, SRS2 and RAD52, suggested that the genes act soon after T-DNA entry for modification of the chromosomal T-DNA to stably maintain them as linear replicons and to circularize certain T-DNA simultaneously. The cell wall synthesis regulator SMI1 might have a role in the cell surface interaction between the donor and recipient cells, but the smi1Δ mutant exhibited pleiotropic effect, i.e. low effector protein transport as well as low AMT for the chromosomal T-DNA, but relatively high AMT for integrative T-DNAs. The ergosterol synthesis regulator/enzyme-scaffold gene ERG28 probably contributes by sensing a congested environment, because growth of erg28Δ strain was unaffected by the presence of donor bacterial cells, while the growth of the wild-type and other mutant yeast strains was suppressed by their presence. RAD52 and the DNA helicase/anti-recombinase gene SRS2 are necessary to form and maintain artificial chromosomes through the AMT of chromosomal T-DNA. A sterol synthesis scaffold gene ERG28 is important in the high

  20. Inactivation of p15INK4b in chronic arsenic poisoning cases

    Directory of Open Access Journals (Sweden)

    Aihua Zhang

    2014-01-01

    Full Text Available Arsenic exposure from burning high arsenic-containing coal has been associated with human skin lesion and cancer. However, the mechanisms of arsenic-related carcinogenesis are not fully understood. Inactivation of critical tumor suppression genes by epigenetic regulation or genetic modification might contribute to arsenic-induced carcinogenicity. This study aims to clarify the correlation between arsenic pollution and functional defect of p15INK4b gene in arsenic exposure residents from a region of Guizhou Province, China. To this end, 103 arsenic exposure residents and 105 control subjects were recruited in this study. The results showed that the exposure group exhibited higher levels of urinary and hair arsenic compared with the control group (55.28 vs 28.87 μg/L, 5.16 vs 1.36 μg/g. Subjects with higher arsenic concentrations are more likely to have p15INK4b methylation and gene deletion (χ2 = 4.28, P = 0.04 and χ2 = 4.31, P = 0.04. We also found that the degree of p15INK4b hypermethylation and gene deletion occurred at higher incidence in the poisoning cases with skin cancer (3.7% and 14.81% in non-skin cancer group, 41.18% and 47.06 in skin cancer group, and were significantly associated with the stage of skin lesions (χ2 = 12.82, P < 0.01 and χ2 = 7.835, P = 0.005. These observations indicate that inactivation of p15INK4b through genetic alteration or epigenetic modification is a common event that is associated with arsenic exposure and the development of arsenicosis.

  1. Sequence analysis of the DNA-repair gene rad51 in the tardigrades Milnesium cf. tardigradum, Hypsibius dujardini and Macrobiotus cf. harmsworthi

    Directory of Open Access Journals (Sweden)

    Eliana A. Beltrán-Pardo

    2013-05-01

    Full Text Available Tardigrades are known for being resistant to extreme conditions, including tolerance to ionising and UV radiation in both the hydrated and the dehydrated state. It is known that these factors may cause damage to DNA. It has recently been shown that single and double DNA strand breaks occur when tardigrades are maintained for a long time in the anhydrobiotic state. This may suggest that perhaps tardigrades rely on efficient DNA repair mechanisms. Among all proteins that comprise the DNA repair system, recombinases such as RecA or Rad51 have a very important function: DNA exchange activity. This enzyme is used in the homologous recombination and allows repair of the damaged strand using homologous non-damaged strands as a template. In this study, Rad51 induction was evaluated by western blot in Milnesium cf. tardigradum, after exposure to gamma radiation. The Rad51 protein was highly induced by radiation, when compared to the control. The rad51 genes were searched in three tardigrades: Milnesium cf. tardigradum, Hypsibius dujardini and Macrobiotus cf. harmsworthi. The gene sequences were obtained by preparing and sequencing transcriptome libraries for H. dujardini and M. cf. harmsworthi and designing rad51 degenerate primers specific for M. cf. tardigradum. Comparison of Rad51 putative proteins from tardigrades with other organisms showed that they are highly similar to the corresponding sequence from the nematode Trichinella spiralis. A structure-based sequence alignment from tardigrades and other organisms revealed that putative Rad51 predicted proteins from tardigrades contain the expected motifs for these important recombinases. In a cladogram tree based on this alignment, tardigrades tend to cluster together suggesting that they have selective differences in these genes that make them diverge between species. Predicted Rad51 structures from tardigrades were also compared with crystalline structure of Rad51 in Saccharomyces cerevisiae. These

  2. Variation within 3'-UTRs of base excision repair genes and response to therapy in colorectal cancer patients: A potential modulation of microRNAs binding.

    Science.gov (United States)

    Pardini, Barbara; Rosa, Fabio; Barone, Elisa; Di Gaetano, Cornelia; Slyskova, Jana; Novotny, Jan; Levy, Miroslav; Garritano, Sonia; Vodickova, Ludmila; Buchler, Tomas; Gemignani, Federica; Landi, Stefano; Vodicka, Pavel; Naccarati, Alessio

    2013-11-01

    Colorectal cancer is routinely treated with a 5-fluorouracil (5-FU)-based chemotherapy. 5-FU incorporates into DNA, and the base excision repair (BER) pathway specifically recognizes such damage. We investigated the association of single-nucleotide polymorphisms (SNP) in the 3'-untranslated regions (UTR) of BER genes, and potentially affecting the microRNA (miRNA) binding, on the risk of colorectal cancer, its progression, and prognosis. SNPs in miRNA-binding sites may modulate the posttranscriptional regulation of gene expression operated by miRNAs and explain interindividual variability in BER capacity and response to 5-FU. We tested 12 SNPs in the 3'-UTRs of five BER genes for colorectal cancer susceptibility in a case-control study (1,098 cases and 1,459 healthy controls). Subsequently, we analyzed the role of these SNPs on clinical outcomes of patients (866 in the Training set and 232 in the Replication set). SNPs in the SMUG1 and NEIL2 genes were associated with overall survival. In particular, SMUG1 rs2233921 TT carriers showed increased survival compared with those with GT/GG genotypes [HR, 0.54; 95% confidence interval (CI), 0.36-0.81; P = 0.003] in the Training set and after pooling results from the Replication set. The association was more significant following stratification for 5-FU-based chemotherapy (P = 5.6 × 10(-5)). A reduced expression of the reporter gene for the T allele of rs2233921 was observed when compared with the common G allele by in vitro assay. None of the genotyped BER polymorphisms were associated with colorectal cancer risk. We provide the first evidence that variations in miRNA-binding sites in BER genes 3'-UTR may modulate colorectal cancer prognosis and therapy response.

  3. Arsenic poisoning of Bangladesh groundwater

    Science.gov (United States)

    Nickson, Ross; McArthur, John; Burgess, William; Ahmed, Kazi Matin; Ravenscroft, Peter; Rahmanñ, Mizanur

    1998-09-01

    In Bangladesh and West Bengal, alluvial Ganges aquifers used for public water supply are polluted with naturally occurring arsenic, which adversely affects the health of millions of people. Here we show that the arsenic derives from the reductive dissolution of arsenic-rich iron oxyhydroxides, which in turn are derived from weathering of base-metal sulphides. This finding means it should now be possible, by sedimentological study of the Ganges alluvial sediments, to guide the placement of new water wells so they will be free of arsenic.

  4. Trace metals alter DNA repair and histone modification pathways concurrently in mouse embryonic stem cells.

    Science.gov (United States)

    Gadhia, Sanket R; Calabro, Anthony R; Barile, Frank A

    2012-07-20

    Exposure to metals alters gene expression, changes transcription rates or interferes with DNA repair mechanisms. We tested a hypothesis to determine whether in vitro acute metal exposure, with or without recovery, alters epigenetic pathways in mouse embryonic stem (mES) cells. We measured cell viability, total and histone protein production, changes in gene expression for differentiation and DNA repair, and histone lysine mono-methylation (H3K27me1), in differentiated cells. Confluent differentiated cultures of mES cells were exposed to arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), lithium (Li), mercury (Hg), and nickel (Ni), for 1-h and 24-h, followed by a recovery period. The data demonstrate that maximum cell death occurred during the first few hours of exposure at 24-h IC₅₀ concentrations for all metals. Prolonged in vitro exposure to metals at low concentrations also inhibited protein production and cell proliferation. Subsequently, we determined that metals alter cell differentiation (Oct-4 and egfr) and DNA repair mechanisms (Rad-18, Top-3a and Ogg-1). Interestingly, As, Cd, Hg, and Ni decreased cell proliferation to a greater extent than total histone protein production. Yet, at equivalent concentrations, As and Hg significantly decreased total histone protein production per cell compared to respective controls, suggesting suppression of repair or compensatory mechanisms involving histone pathways. And, acute exposure to As, Cd, Hg and Ni decreased H3K27me1 residue, when compared to control cells. Because activation of cellular differentiation, histone modification, and DNA repair are linked by common transcriptional pathways, and the data propose that metals alter these conduits, then it is reasonable to conclude that trace quantities of metals are capable of suppressing regulation of chromatin structure, cellular differentiation, and controlled cell proliferation in mES cells. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  5. Pulsed low-level infrared laser alters mRNA levels from muscle repair genes dependent on power output in Wistar rats

    Science.gov (United States)

    Trajano, L. A. S. N.; Trajano, E. T. L.; Thomé, A. M. C.; Sergio, L. P. S.; Mencalha, A. L.; Stumbo, A. C.; Fonseca, A. S.

    2017-10-01

    Satellite cells are present in skeletal muscle functioning in the repair and regeneration of muscle injury. Activation of these cells depends on the expression of myogenic factor 5 (Myf5), myogenic determination factor 1(MyoD), myogenic regulatory factor 4 (MRF4), myogenin (MyoG), paired box transcription factors 3 (Pax3), and 7 (Pax7). Low-level laser irradiation accelerates the repair of muscle injuries. However, data from the expression of myogenic factors have been controversial. Furthermore, the effects of different laser beam powers on the repair of muscle injuries have been not evaluated. The aim of this study was to evaluate the effects of low-level infrared laser at different powers and in pulsed emission mode on the expression of myogenic regulatory factors and on Pax3 and Pax7 in injured skeletal muscle from Wistar rats. Animals that underwent cryoinjury were divided into three groups: injury, injury laser 25 Mw, and injury laser 75 mW. Low-level infrared laser irradiation (904 nm, 3 J cm-2, 5 kHz) was carried out at 25 and 75 mW. After euthanasia, skeletal muscle samples were withdrawn and the total RNA was extracted for the evaluation of mRNA levels from the MyoD, MyoG, MRF4, Myf5, Pax3, and Pax7 gene. Pax 7 mRNA levels did not alter, but Pax3 mRNA levels increased in the injured and laser-irradiated group at 25 mW. MyoD, MyoG, and MYf5 mRNA levels increased in the injured and laser-irradiated animals at both powers, and MRF4 mRNA levels decreased in the injured and laser-irradiated group at 75 mW. In conclusion, exposure to pulsed low-level infrared laser, by power-dependent effect, could accelerate the muscle repair process altering mRNA levels from paired box transcription factors and myogenic regulatory factors.

  6. Metagenomic study of red biofilms from Diamante Lake reveals ancient arsenic bioenergetics in haloarchaea.

    Science.gov (United States)

    Rascovan, Nicolás; Maldonado, Javier; Vazquez, Martín P; Eugenia Farías, María

    2016-02-01

    Arsenic metabolism is proposed to be an ancient mechanism in microbial life. Different bacteria and archaea use detoxification processes to grow under high arsenic concentration. Some of them are also able to use arsenic as a bioenergetic substrate in either anaerobic arsenate respiration or chemolithotrophic growth on arsenite. However, among the archaea, bioenergetic arsenic metabolism has only been found in the Crenarchaeota phylum. Here we report the discovery of haloarchaea (Euryarchaeota phylum) biofilms forming under the extreme environmental conditions such as high salinity, pH and arsenic concentration at 4589 m above sea level inside a volcano crater in Diamante Lake, Argentina. Metagenomic analyses revealed a surprisingly high abundance of genes used for arsenite oxidation (aioBA) and respiratory arsenate reduction (arrCBA) suggesting that these haloarchaea use arsenic compounds as bioenergetics substrates. We showed that several haloarchaea species, not only from this study, have all genes required for these bioenergetic processes. The phylogenetic analysis of aioA showed that haloarchaea sequences cluster in a novel and monophyletic group, suggesting that the origin of arsenic metabolism in haloarchaea is ancient. Our results also suggest that arsenite chemolithotrophy likely emerged within the archaeal lineage. Our results give a broad new perspective on the haloarchaea metabolism and shed light on the evolutionary history of arsenic bioenergetics.

  7. Association between single nucleotide polymorphisms of X-ray repair cross-complementing protein 4 gene and development of pancreatic cancer.

    Science.gov (United States)

    Ding, Y; Li, L N

    2015-08-14

    We performed a study to evaluate X-ray repair cross-complementing protein 4 (XRCC4) gene polymorphisms and the development of pancreatic cancer. A case-control study including 206 patients with newly diagnosed primary pancreatic cancer and 412 controls was performed between January 2011 and October 2013 in a Chinese population. Genotypes of XRCC4 rs1805377, rs2075685, rs2075686 and rs1056503 were determined using polymerase chain reaction combined with a restriction fragment length polymorphism assay. Compared with controls, pancreatic cancer patients were more likely to have a higher body mass index, family history of cancer, and a habit of alcohol drinking compared with controls (P pancreatic cancer compared to those with the GG genotype, with an odds ratio (95% confidence interval) of 1.88 (1.15-3.08). Our results suggest that the XRCC4 rs2075685 polymorphism could influence the susceptibility to pancreatic cancer in a Chinese population.

  8. Castration attenuates myelin repair following lysolecithin induced demyelination in rat optic chiasm: an evaluation using visual evoked potential, marker genes expression and myelin staining.

    Science.gov (United States)

    Sherafat, Mohammad Amin; Javan, Mohammad; Mozafari, Sabah; Mirnajafi-Zadeh, Javad; Motamedi, Fereshteh

    2011-10-01

    Multiple sclerosis (MS) is a demyelinating disease that affects the central nervous system. MS is the most common neurological disorder in young adults with a greater incidence among females. Male gonadal hormones have a protective effect on neural system development and myelin maturation. In this study, we investigate the effect of castration on lysolecithin-induced demyelination and remyelination processes using visual evoked potentials, in addition to measuring the expressions of Olig2, MBP, Nogo-A and GFAP mRNAs as oligodendrocyte or astrocyte markers; and histological assessments by myelin-specific staining. We observed more expanded demyelination with delayed repair process in castrated rats. Expression levels of the aforementioned marker genes confirmed histological and electrophysiological observations. Our results showed a pivotal role for endogenous male hormones in the context of demyelinating insults. It may also account for the different prognosis of MS between male and female genders and provide new insights for therapeutic treatments.

  9. Genetic and Molecular Dissection of Arsenic Hyperaccumulation in the fern Pteris vittata.

    Energy Technology Data Exchange (ETDEWEB)

    Jo Ann Banks; David Salt

    2008-04-04

    Pteris vittata is a fern that is extraordinary in its ability to tolerate hyperaccumulate high levels of arsenic (As). The goals of the proposed research, to identify the genes that are necessary for As hyperaccumulation in P. vittata using molecular and genetic approaches and to understand the physiology of arsenic uptake and distribution in the living plant, were accomplished during the funding period. The genes that have been identified may ultimately enable the engineering or selection of other plants capable of As hyperaccumulation. This is important for the phytoremediation of arsenic-contaminated soils in areas where P. vittata cannot grow.

  10. Mouse BAZ1A (ACF1 is dispensable for double-strand break repair but is essential for averting improper gene expression during spermatogenesis.

    Directory of Open Access Journals (Sweden)

    James A Dowdle

    2013-11-01

    Full Text Available ATP-dependent chromatin remodelers control DNA access for transcription, recombination, and other processes. Acf1 (also known as BAZ1A in mammals is a defining subunit of the conserved ISWI-family chromatin remodelers ACF and CHRAC, first purified over 15 years ago from Drosophila melanogaster embryos. Much is known about biochemical properties of ACF and CHRAC, which move nucleosomes in vitro and in vivo to establish ordered chromatin arrays. Genetic studies in yeast, flies and cultured human cells clearly implicate these complexes in transcriptional repression via control of chromatin structures. RNAi experiments in transformed mammalian cells in culture also implicate ACF and CHRAC in DNA damage checkpoints and double-strand break repair. However, their essential in vivo roles in mammals are unknown. Here, we show that Baz1a-knockout mice are viable and able to repair developmentally programmed DNA double-strand breaks in the immune system and germ line, I-SceI endonuclease-induced breaks in primary fibroblasts via homologous recombination, and DNA damage from mitomycin C exposure in vivo. However, Baz1a deficiency causes male-specific sterility in accord with its high expression in male germ cells, where it displays dynamic, stage-specific patterns of chromosomal localization. Sterility is caused by pronounced defects in sperm development, most likely a consequence of massively perturbed gene expression in spermatocytes and round spermatids in the absence of BAZ1A: the normal spermiogenic transcription program is largely intact but more than 900 other genes are mis-regulated, primarily reflecting inappropriate up-regulation. We propose that large-scale changes in chromatin composition that occur during spermatogenesis create a window of vulnerability to promiscuous transcription changes, with an essential function of ACF and/or CHRAC chromatin remodeling activities being to safeguard against these alterations.

  11. Whole transcriptome analysis reveals an 8-oxoguanine DNA glycosylase-1-driven DNA repair-dependent gene expression linked to essential biological processes.

    Science.gov (United States)

    Aguilera-Aguirre, Leopoldo; Hosoki, Koa; Bacsi, Attila; Radák, Zsolt; Wood, Thomas G; Widen, Steven G; Sur, Sanjiv; Ameredes, Bill T; Saavedra-Molina, Alfredo; Brasier, Allan R; Ba, Xueqing; Boldogh, Istvan

    2015-04-01

    Reactive oxygen species inflict oxidative modifications on various biological molecules, including DNA. One of the most abundant DNA base lesions, 8-oxo-7,8-dihydroguanine (8-oxoG) is repaired by 8-oxoguanine DNA glycosylase-1 (OGG1) during DNA base excision repair (OGG1-BER). 8-OxoG accumulation in DNA has been associated with various pathological and aging processes, although its role is unclear. The lack of OGG1-BER in Ogg1(-/-) mice resulted in decreased inflammatory responses and increased susceptibility to infections and metabolic disorders. Therefore, we proposed that OGG1 and/or 8-oxoG base may have a role in immune and homeostatic processes. To test our hypothesis, we challenged mouse lungs with OGG1-BER product 8-oxoG base and changes in gene expression were determined by RNA sequencing and data were analyzed by Gene Ontology and statistical tools. RNA-Seq analysis identified 1592 differentially expressed (≥ 3-fold change) transcripts. The upregulated mRNAs were related to biological processes, including homeostatic, immune-system, macrophage activation, regulation of liquid-surface tension, and response to stimulus. These processes were mediated by chemokines, cytokines, gonadotropin-releasing hormone receptor, integrin, and interleukin signaling pathways. Taken together, these findings point to a new paradigm showing that OGG1-BER plays a role in various biological processes that may benefit the host, but when in excess could be implicated in disease and/or aging processes. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Pathways for arsenic from sediments to groundwater to streams: Biogeochemical processes in the Inner Coastal Plain, New Jersey, USA

    Science.gov (United States)

    Barringer, Julia L.; Mumford, Adam; Young, Lily Y.; Reilly, Pamela A.; Bonin, Jennifer L.; Rosman, Robert

    2010-01-01

    The Cretaceous and Tertiary sediments that underlie the Inner Coastal Plain of New Jersey contain the arsenic-rich mineral glauconite. Streambed sediments in two Inner Coastal Plain streams (Crosswicks and Raccoon Creeks) that traverse these glauconitic deposits are enriched in arsenic (15–25 mg/kg), and groundwater discharging to the streams contains elevated levels of arsenic (>80 μg/L at a site on Crosswicks Creek) with arsenite generally the dominant species. Low dissolved oxygen, low or undetectable levels of nitrate and sulfate, detectable sulfide concentrations, and high concentrations of iron and dissolved organic carbon (DOC) in the groundwater indicate that reducing environments are present beneath the streambeds and that microbial activity, fueled by the DOC, is involved in releasing arsenic and iron from the geologic materials. In groundwater with the highest arsenic concentrations at Crosswicks Creek, arsenic respiratory reductase gene (arrA) indicated the presence of arsenic-reducing microbes. From extracted DNA, 16s rRNA gene sequences indicate the microbial community may include arsenic-reducing bacteria that have not yet been described. Once in the stream, iron is oxidized and precipitates as hydroxide coatings on the sediments. Arsenite also is oxidized and co-precipitates with or is sorbed to the iron hydroxides. Consequently, dissolved arsenic concentrations are lower in streamwater than in the groundwater, but the arsenic contributed by groundwater becomes part of the arsenic load in the stream when sediments are suspended during high flow. A strong positive relation between concentrations of arsenic and DOC in the groundwater samples indicates that any process—natural or anthropogenic—that increases the organic carbon concentration in the groundwater could stimulate microbial activity and thus increase the amount of arsenic that is released from the geologic materials.

  13. Pathways for arsenic from sediments to groundwater to streams: biogeochemical processes in the Inner Coastal Plain, New Jersey, USA.

    Science.gov (United States)

    Barringer, Julia L; Mumford, Adam; Young, Lily Y; Reilly, Pamela A; Bonin, Jennifer L; Rosman, Robert

    2010-11-01

    The Cretaceous and Tertiary sediments that underlie the Inner Coastal Plain of New Jersey contain the arsenic-rich mineral glauconite. Streambed sediments in two Inner Coastal Plain streams (Crosswicks and Raccoon Creeks) that traverse these glauconitic deposits are enriched in arsenic (15-25mg/kg), and groundwater discharging to the streams contains elevated levels of arsenic (>80μg/L at a site on Crosswicks Creek) with arsenite generally the dominant species. Low dissolved oxygen, low or undetectable levels of nitrate and sulfate, detectable sulfide concentrations, and high concentrations of iron and dissolved organic carbon (DOC) in the groundwater indicate that reducing environments are present beneath the streambeds and that microbial activity, fueled by the DOC, is involved in releasing arsenic and iron from the geologic materials. In groundwater with the highest arsenic concentrations at Crosswicks Creek, arsenic respiratory reductase gene (arrA) indicated the presence of arsenic-reducing microbes. From extracted DNA, 16s rRNA gene sequences indicate the microbial community may include arsenic-reducing bacteria that have not yet been described. Once in the stream, iron is oxidized and precipitates as hydroxide coatings on the sediments. Arsenite also is oxidized and co-precipitates with or is sorbed to the iron hydroxides. Consequently, dissolved arsenic concentrations are lower in streamwater than in the groundwater, but the arsenic contributed by groundwater becomes part of the arsenic load in the stream when sediments are suspended during high flow. A strong positive relation between concentrations of arsenic and DOC in the groundwater samples indicates that any process-natural or anthropogenic-that increases the organic carbon concentration in the groundwater could stimulate microbial activity and thus increase the amount of arsenic that is released from the geologic materials. Published by Elsevier Ltd.

  14. INFLUENCE OF DIETARY ARSENIC ON URINARY ARSENIC METABOLITE EXCRETION

    Science.gov (United States)

    Influence of Dietary Arsenic on Urinary Arsenic Metabolite ExcretionCara L. Carty, M.S., Edward E. Hudgens, B.Sc., Rebecca L. Calderon, Ph.D., M.S.P.H., Richard Kwok, M.S.P.H., Epidemiology and Biomarkers Branch/HSD, NHEERL/US EPA; David J. Thomas, Ph.D., Pharmacokinetics...

  15. Arsenic speciation in edible mushrooms.

    Science.gov (United States)

    Nearing, Michelle M; Koch, Iris; Reimer, Kenneth J

    2014-12-16

    The fruiting bodies, or mushrooms, of terrestrial fungi have been found to contain a high proportion of the nontoxic arsenic compound arsenobetaine (AB), but data gaps include a limited phylogenetic diversity of the fungi for which arsenic speciation is available, a focus on mushrooms with higher total arsenic concentrations, and the unknown formation and role of AB in mushrooms. To address these, the mushrooms of 46 different fungus species (73 samples) over a diverse range of phylogenetic groups were collected from Canadian grocery stores and background and arsenic-contaminated areas. Total arsenic was determined using ICP-MS, and arsenic speciation was determined using HPLC-ICP-MS and complementary X-ray absorption spectroscopy (XAS). The major arsenic compounds in mushrooms were found to be similar among phylogenetic groups, and AB was found to be the major compound in the Lycoperdaceae and Agaricaceae families but generally absent in log-growing mushrooms, suggesting the microbial community may influence arsenic speciation in mushrooms. The high proportion of AB in mushrooms with puffball or gilled morphologies may suggest that AB acts as an osmolyte in certain mushrooms to help maintain fruiting body structure. The presence of an As(III)-sulfur compound, for the first time in mushrooms, was identified in the XAS analysis. Except for Agaricus sp. (with predominantly AB), inorganic arsenic predominated in most of the store-bought mushrooms (albeit with low total arsenic concentrations). Should inorganic arsenic predominate in these mushrooms from contaminated areas, the risk to consumers under these circumstances should be considered.

  16. The TAO-Gen Algorithm for Identifying Gene Interaction Networks with Application to SOS Repair in E. coli

    Science.gov (United States)

    Yamanaka, Takeharu; Toyoshiba, Hiroyoshi; Sone, Hideko; Parham, Frederick M.; Portier, Christopher J.

    2004-01-01

    One major unresolved issue in the analysis of gene expression data is the identification and quantification of gene regulatory networks. Several methods have been proposed for identifying gene regulatory networks, but these methods predominantly focus on the use of multiple pairwise comparisons to identify the network structure. In this article, we describe a method for analyzing gene expression data to determine a regulatory structure consistent with an observed set of expression profiles. Unlike other methods this method goes beyond pairwise evaluations by using likelihood-based statistical methods to obtain the network that is most consistent with the complete data set. The proposed algorithm performs accurately for moderate-sized networks with most errors being minor additions of linkages. However, the analysis also indicates that sample sizes may need to be increased to uniquely identify even moderate-sized networks. The method is used to evaluate interactions between genes in the SOS signaling pathway in Escherichia coli using gene expression data where each gene in the network is over-expressed using plasmids inserts. PMID:15598612

  17. Gene-Silencing Screen for Mammalian Axon Regeneration Identifies Inpp5f (Sac2) as an Endogenous Suppressor of Repair after Spinal Cord Injury.

    Science.gov (United States)

    Zou, Yixiao; Stagi, Massimiliano; Wang, Xingxing; Yigitkanli, Kazim; Siegel, Chad S; Nakatsu, Fubito; Cafferty, William B J; Strittmatter, Stephen M

    2015-07-22

    Axonal growth and neuronal rewiring facilitate functional recovery after spinal cord injury. Known interventions that promote neural repair remain limited in their functional efficacy. To understand genetic determinants of mammalian CNS axon regeneration, we completed an unbiased RNAi gene-silencing screen across most phosphatases in the genome. We identified one known and 17 previously unknown phosphatase suppressors of injury-induced CNS axon growth. Silencing Inpp5f (Sac2) leads to robust enhancement of axon regeneration and growth cone reformation. Results from cultured Inpp5f(-/-) neurons confirm lentiviral shRNA results from the screen. Consistent with the nonoverlapping substrate specificity between Inpp5f and PTEN, rapamycin does not block enhanced regeneration in Inpp5f(-/-) neurons, implicating mechanisms independent of the PI3K/AKT/mTOR pathway. Inpp5f(-/-) mice develop normally, but show enhanced anatomical and functional recovery after mid-thoracic dorsal hemisection injury. More serotonergic axons sprout and/or regenerate caudal to the lesion level, and greater numbers of corticospinal tract axons sprout rostral to the lesion. Functionally, Inpp5f-null mice exhibit enhanced recovery of motor functions in both open-field and rotarod tests. This study demonstrates the potential of an unbiased high-throughput functional screen to identify endogenous suppressors of CNS axon growth after injury, and reveals Inpp5f (Sac2) as a novel suppressor of CNS axon repair after spinal cord injury. Significance statement: The extent of axon regeneration is a critical determinant of neurological recovery from injury, and is extremely limited in the adult mammalian CNS. We describe an unbiased gene-silencing screen that uncovered novel molecules suppressing axonal regeneration. Inpp5f (Sac2) gene deletion promoted recovery from spinal cord injury with no side effects. The mechanism of action is distinct from another lipid phosphatase implicated in regeneration, PTEN

  18. A polymorphism in the base excision repair gene PARP2 is associated with differential prognosis by chemotherapy among postmenopausal breast cancer patients

    NARCIS (Netherlands)

    P. Seibold (Petra); P. Schmezer (Peter); T.W. Behrens (Timothy); K. Michailidou (Kyriaki); M.K. Bolla (Manjeet); Q. Wang (Qing); D. Flesch-Janys (Dieter); H. Nevanlinna (Heli); R. Fagerholm (Rainer); K. Aittomäki (Kristiina); C. Blomqvist (Carl); S. Margolin (Sara); A. Mannermaa (Arto); V. Kataja (Vesa); V-M. Kosma (Veli-Matti); J.M. Hartikainen (J.); D. Lambrechts (Diether); H. Wildiers (Hans); V. Kristensen (Vessela); G.G. Alnæs (Grethe Grenaker); S. Nord (Silje); A.-L. Borresen-Dale (Anne-Lise); M.J. Hooning (Maartje); A. Hollestelle (Antoinette); A. Jager (Agnes); C.M. Seynaeve (Caroline); J. Li (Jingmei); J. Liu (Jianjun); M.K. Humphreys (Manjeet); A.M. Dunning (Alison); V. Rhenius (Valerie); M. Shah (Mitul); M. Kabisch (Maria); D. Torres (Diana); H.U. Ulmer (Hans); U. Hamann (Ute); J.M. Schildkraut (Joellen M.); K.S. Purrington (Kristen S.); F.J. Couch (Fergus); P. Hall (Per); P.D.P. Pharoah (Paul); D.F. Easton (Douglas); M.K. Schmidt (Marjanka); J. Chang-Claude (Jenny); O. Popanda (Odilia)

    2015-01-01

    textabstractBackground: Personalized therapy considering clinical and genetic patient characteristics will further improve breast cancer survival. Two widely used treatments, chemotherapy and radiotherapy, can induce oxidative DNA damage and, if not repaired, cell death. Since base excision repair

  19. Genomic analysis of stress response against arsenic in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Surasri N Sahu

    Full Text Available Arsenic, a known human carcinogen, is widely distributed around the world and found in particularly high concentrations in certain regions including Southwestern US, Eastern Europe, India, China, Taiwan and Mexico. Chronic arsenic poisoning affects millions of people worldwide and is associated with increased risk of many diseases including arthrosclerosis, diabetes and cancer. In this study, we explored genome level global responses to high and low levels of arsenic exposure in Caenorhabditis elegans using Affymetrix expression microarrays. This experimental design allows us to do microarray analysis of dose-response relationships of global gene expression patterns. High dose (0.03% exposure caused stronger global gene expression changes in comparison with low dose (0.003% exposure, suggesting a positive dose-response correlation. Biological processes such as oxidative stress, and iron metabolism, which were previously reported to be involved in arsenic toxicity studies using cultured cells, experimental animals, and humans, were found to be affected in C. elegans. We performed genome-wide gene expression comparisons between our microarray data and publicly available C. elegans microarray datasets of cadmium, and sediment exposure samples of German rivers Rhine and Elbe. Bioinformatics analysis of arsenic-responsive regulatory networks were done using FastMEDUSA program. FastMEDUSA analysis identified cancer-related genes, particularly genes associated with leukemia, such as dnj-11, which encodes a protein orthologous to the mammalian ZRF1/MIDA1/MPP11/DNAJC2 family of ribosome-associated molecular chaperones. We analyzed the protective functions of several of the identified genes using RNAi. Our study indicates that C. elegans could be a substitute model to study the mechanism of metal toxicity using high-throughput expression data and bioinformatics tools such as FastMEDUSA.

  20. CALM/AF10-positive leukemias show upregulation of genes involved in chromatin assembly and DNA repair processes and of genes adjacent to the breakpoint at 10p12.

    Science.gov (United States)

    Mulaw, M A; Krause, A; Krause, A J; Deshpande, A J; Krause, L F; Rouhi, A; La Starza, R; Borkhardt, A; Buske, C; Mecucci, C; Ludwig, W-D; Lottaz, C; Bohlander, S K

    2012-05-01

    The t(10;11)(p12;q14) is a recurring chromosomal translocation that gives rise to the CALM/AF10 fusion gene, which is found in acute myeloid leukemia, acute lymphoblastic leukemia and malignant lymphoma. We analyzed the fusion transcripts in 20 new cases of CALM/AF10-positive leukemias, and compared the gene expression profile of 10 of these to 125 patients with other types of leukemia and 10 normal bone marrow samples. Based on gene set enrichment analyses, the CALM/AF10-positive samples showed significant upregulation of genes involved in chromatin assembly and maintenance and DNA repair process, and downregulation of angiogenesis and cell communication genes. Interestingly, we observed a striking upregulation of four genes located immediately centromeric to the break point of the t(10;11)(p12;q14) on 10p12 (COMMD3 (COMM domain containing 3), BMI1 (B lymphoma Mo-MLV insertion region 1 homolog), DNAJC1 (DnaJ (Hsp40) homolog subfamily C member 1) and SPAG6 (sperm associated antigen 6)). We also conducted semiquantitative reverse transcriptase-PCR analysis on leukemic blasts from a murine CALM/AF10 transplantation model that does not have the translocation. Commd3, Bmi1 and Dnajc1, but not Spag6 were upregulated in these samples. These results strongly indicate that the differential regulation of these three genes is not due to the break point effect but as a consequence of the CALM/AF10 fusion gene expression, though the mechanism of regulation is not well understood.

  1. Arsenic levels in groundwater aquifer

    African Journals Online (AJOL)

    Miodrag Jelic

    Varying levels of arsenic in both industrial and sanitary waters were determined, indicating water pollution with arsenic compounds. The horizontal ...... Geochem. 113: 163-181. Thu LT, Quang Toan ET (2001). Country Report of Vietnam. Workshop on Drinking Water Quality Surveillance and Safety, Kuala Lumpur: pp. 42-48 ...

  2. Drinking Water Arsenic Rule History

    Science.gov (United States)

    The EPA published the final arsenic rule on January 22, 2001. In response to the national debate surrounding the arsenic rule related to science and costs, the EPA announced on March 20, 2001 that the agency would reassess the science and cost issues.

  3. Bioscorodite crystallization for arsenic removal

    NARCIS (Netherlands)

    Gonzalez-Contreras, P.A.; Huisman, J.; Weijma, J.; Buisman, C.J.N.

    2011-01-01

    In the bio-scorodite process, arsenic is precipitated as crystalline iron arsenate, i.e. scorodite (FeAsO4·2H2O). This is a more economic and more environmentally friendly method for arsenic immobilization than the chemical production of iron- or calcium arsenate, as fewer chemicals are needed.

  4. ARSENIC - SUSCEPTIBILITY & IN UTERO EFFECTS

    Science.gov (United States)

    Exposure to inorganic arsenic remains a serious public health problem at many locations worldwide. If has often been noted that prevalences of signs and symptoms of chronic arsenic poisoning differ among various populations. For example, skin lesions or peripheral vascular dis...

  5. Identification of An Arsenic Tolerant Double Mutant With a Thiol-Mediated Component And Increased Arsenic Tolerance in PhyA Mutants

    Energy Technology Data Exchange (ETDEWEB)

    Sung, D.Y.; Lee, D.; Harris, H.; Raab, A.; Feldmann, J.; Meharg, A.; Kumabe, B.; Komives, E.A.; Schroeder, J.I.; /SLAC, SSRL /Sydney U. /Aberdeen U. /UC, San Diego

    2007-04-06

    A genetic screen was performed to isolate mutants showing increased arsenic tolerance using an Arabidopsis thaliana population of activation tagged lines. The most arsenic-resistant mutant shows increased arsenate and arsenite tolerance. Genetic analyses of the mutant indicate that the mutant contains two loci that contribute to arsenic tolerance, designated ars4 and ars5. The ars4ars5 double mutant contains a single T-DNA insertion, ars4, which co-segregates with arsenic tolerance and is inserted in the Phytochrome A (PHYA) gene, strongly reducing the expression of PHYA. When grown under far-red light conditions ars4ars5 shows the same elongated hypocotyl phenotype as the previously described strong phyA-211 allele. Three independent phyA alleles, ars4, phyA-211 and a new T-DNA insertion allele (phyA-t) show increased tolerance to arsenate, although to a lesser degree than the ars4ars5 double mutant. Analyses of the ars5 single mutant show that ars5 exhibits stronger arsenic tolerance than ars4, and that ars5 is not linked to ars4. Arsenic tolerance assays with phyB-9 and phot1/phot2 mutants show that these photoreceptor mutants do not exhibit phyA-like arsenic tolerance. Fluorescence HPLC analyses show that elevated levels of phytochelatins were not detected in ars4, ars5 or ars4ars5, however increases in the thiols cysteine, gamma-glutamylcysteine and glutathione were observed. Compared with wild type, the total thiol levels in ars4, ars5 and ars4ars5 mutants were increased up to 80% with combined buthionine sulfoximine and arsenic treatments, suggesting the enhancement of mechanisms that mediate thiol synthesis in the mutants. The presented findings show that PHYA negatively regulates a pathway conferring arsenic tolerance, and that an enhanced thiol synthesis mechanism contributes to the arsenic tolerance of ars4ars5.

  6. Arsenic affects inflammatory cytokine expression in Gallus gallus brain tissues.

    Science.gov (United States)

    Sun, Xiao; He, Ying; Guo, Ying; Li, Siwen; Zhao, Hongjing; Wang, Yu; Zhang, Jingyu; Xing, Mingwei

    2017-06-05

    The heavy metal arsenic is widely distributed in nature and posses a serious threat to organism's health. However, little is known about the arsenic-induced inflammatory response in the brain tissues of birds and the relationship and mechanism of the inflammatory response. The purpose of this study was to explore the effects of dietary arsenic on the expression of inflammatory cytokines in the brains of Gallus gallus. Seventy-two 1-day-old male Hy-line chickens were divided into a control group, a low arsenic trioxide (As2O3)-treated (7.5 mg/kg) group, a middle As2O3-treated (15 mg/kg) group, and a high As2O3-treated (30 mg/kg) group. Arsenic exposure caused obvious ultrastructural changes. The mRNA levels of the transcription factor nuclear factor-κB (NF-κB) and of pro-inflammatory cytokines, including inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), and prostaglandin E synthase (PTGEs), in chicken brain tissues (cerebrum, cerebellum, thalamus, brainstem and myelencephalon) on days 30, 60 and 90, respectively, were measured by real-time PCR. The protein expression of iNOS was detected by western blot. The results showed that after being treated with As2O3, the levels of inflammatory-related factor NF-κB and pro-inflammatory cytokines in chicken brain tissues increased (P Arsenic exposure in the chickens triggered host defence and induced an inflammatory response by regulating the expression of inflammatory-related genes in the cerebrum, cerebellum, thalamus, brainstem and myelencephalon. These data form a foundation for further research on arsenic-induced neurotoxicity in Gallus gallus.

  7. Arsenic Mobility and Groundwater Extraction in Bangladesh

    Science.gov (United States)

    Harvey, Charles F.; Swartz, Christopher H.; Badruzzaman, A. B. M.; Keon-Blute, Nicole; Yu, Winston; Ali, M. Ashraf; Jay, Jenny; Beckie, Roger; Niedan, Volker; Brabander, Daniel; Oates, Peter M.; Ashfaque, Khandaker N.; Islam, Shafiqul; Hemond, Harold F.; Ahmed, M. Feroze

    2002-11-01

    High levels of arsenic in well water are causing widespread poisoning in Bangladesh. In a typical aquifer in southern Bangladesh, chemical data imply that arsenic mobilization is associated with recent inflow of carbon. High concentrations of radiocarbon-young methane indicate that young carbon has driven recent biogeochemical processes, and irrigation pumping is sufficient to have drawn water to the depth where dissolved arsenic is at a maximum. The results of field injection of molasses, nitrate, and low-arsenic water show that organic carbon or its degradation products may quickly mobilize arsenic, oxidants may lower arsenic concentrations, and sorption of arsenic is limited by saturation of aquifer materials.

  8. Does risk of endometrial cancer for women without a germline mutation in a DNA mismatch repair gene depend on family history of endometrial cancer or colorectal cancer?

    Science.gov (United States)

    Bharati, Rajani; Jenkins, Mark A; Lindor, Noralane M; Le Marchand, Loïc; Gallinger, Steven; Haile, Robert W; Newcomb, Polly A; Hopper, John L; Win, Aung Ko

    2014-05-01

    To determine whether risk of endometrial cancer for women without a germline mutation in a DNA mismatch repair (MMR) gene depends on family history of endometrial or colorectal cancer. We retrospectively followed a cohort of 79,166 women who were recruited to the Colon Cancer Family Registry, after exclusion of women who were relatives of a carrier of a MMR gene mutation. The Kaplan-Meier failure method was used to estimate the cumulative risk of endometrial cancer. Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for association between family history of endometrial or colorectal cancer and risk of endometrial cancer. A total of 628 endometrial cancer cases were observed, with mean age at diagnosis of 54.4 (standard deviation: 15.7) years. The cumulative risk of endometrial cancer to age 70 years was estimated to be 0.94% (95% CI 0.83-1.05) for women with no family history of endometrial cancer, and 3.80% (95% CI 2.75-4.98) for women with at least one first- or second-degree relative with endometrial cancer. Compared with women without family history, we found an increased risk of endometrial cancer for women with at least one first- or second-degree relative with endometrial cancer (HR 3.66, 95% CI 2.63-5.08), and for women with one first-degree relative with colorectal cancer diagnosed at age cancer is associated with a family history of endometrial cancer or early-onset colorectal cancer for women without a MMR gene mutation, indicating for potential underlying genetic and environmental factors shared by colorectal and endometrial cancers other than caused by MMR gene mutations. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Cortical gene expression in spinal cord injury and repair: insight into the functional complexity of the neural regeneration program

    Directory of Open Access Journals (Sweden)

    Fabian eKruse

    2011-09-01

    Full Text Available Traumatic spinal cord injury (SCI results in the formation of a fibrous scar acting as a growth barrier for regenerating axons at the lesion site. We have previously shown (Klapka et al., 2005 that transient suppression of the inhibitory lesion scar in rat spinal cord leads to long distance axon regeneration, retrograde rescue of axotomized cortical motoneurons and improvement of locomotor function. Here we applied a systemic approach to investigate for the first time specific and dynamic alterations in the cortical gene expression profile following both thoracic SCI and regeneration-promoting anti-scarring treatment (AST. In order to monitor cortical gene expression we carried out microarray analyses using total RNA isolated from layer V/VI of rat sensorimotor cortex at 1-60 days post-operation (dpo. We demonstrate that cortical neurons respond to injury by massive changes in gene expression, starting as early as 1 dpo. AST, in turn, results in profound modifications of the lesion-induced expression profile. The treatment attenuates SCI-triggered transcriptional changes of genes related to inhibition of axon growth and impairment of cell survival, while upregulating the expression of genes associated with axon outgrowth, cell protection and neural development. Thus, AST not only modifies the local environment impeding spinal cord regeneration by reduction of fibrous scarring in the injured spinal cord, but, in addition, strikingly changes the intrinsic capacity of cortical pyramidal neurons towards enhanced cell maintenance and axonal regeneration.

  10. Expression of the mismatch repair gene hMLH1 is enhanced in non-small cell lung cancer with EGFR mutations.

    Directory of Open Access Journals (Sweden)

    Mei Li

    Full Text Available Mismatch repair (MMR plays a pivotal role in keeping the genome stable. MMR dysfunction can lead to carcinogenesis by gene mutation accumulation. HMSH2 and hMLH1 are two key components of MMR. High or low expression of them often mark the status of MMR function. Mutations (EGFR, KRAS, etc are common in non-small cell lung cancer (NSCLC. However, it is not clear what role MMR plays in NSCLC gene mutations. The expression of MMR proteins hMSH2 and hMLH1, and the proliferation markers PCNA and Ki67 were measured by immunohistochemistry in 181 NSCLCs. EGFR and KRAS mutations were identified by high resolution melting analysis. Stronger hMLH1 expression correlated to a higher frequency of EGFR mutations in exon 19 and 21 (p<0.0005. Overexpression of hMLH1 and the adenocarcinoma subtype were both independent factors that related to EGFR mutations in NSCLCs (p=0.013 and p<0.0005. The expression of hMLH1, hMSH2 and PCNA increased, while Ki67 expression significantly decreased (p=0.030 in NSCLCs with EGFR mutations. Overexpression of hMLH1 could be a new molecular marker to predict the response to EGFR-TKIs in NSCLCs. Furthermore, EGFR mutations might be an early event of NSCLC that occur before MMR dysfunction.

  11. Pms2 and uracil-DNA glycosylases act jointly in the mismatch repair pathway to generate Ig gene mutations at A-T base pairs.

    Science.gov (United States)

    Girelli Zubani, Giulia; Zivojnovic, Marija; De Smet, Annie; Albagli-Curiel, Olivier; Huetz, François; Weill, Jean-Claude; Reynaud, Claude-Agnès; Storck, Sébastien

    2017-04-03

    During somatic hypermutation (SHM) of immunoglobulin genes, uracils introduced by activation-induced cytidine deaminase are processed by uracil-DNA glycosylase (UNG) and mismatch repair (MMR) pathways to generate mutations at G-C and A-T base pairs, respectively. Paradoxically, the MMR-nicking complex Pms2/Mlh1 is apparently dispensable for A-T mutagenesis. Thus, how detection of U:G mismatches is translated into the single-strand nick required for error-prone synthesis is an open question. One model proposed that UNG could cooperate with MMR by excising a second uracil in the vicinity of the U:G mismatch, but it failed to explain the low impact of UNG inactivation on A-T mutagenesis. In this study, we show that uracils generated in the G1 phase in B cells can generate equal proportions of A-T and G-C mutations, which suggests that UNG and MMR can operate within the same time frame during SHM. Furthermore, we show that Ung-/-Pms2-/- mice display a 50% reduction in mutations at A-T base pairs and that most remaining mutations at A-T bases depend on two additional uracil glycosylases, thymine-DNA glycosylase and SMUG1. These results demonstrate that Pms2/Mlh1 and multiple uracil glycosylases act jointly, each one with a distinct strand bias, to enlarge the immunoglobulin gene mutation spectrum from G-C to A-T bases. © 2017 Girelli Zubani et al.

  12. Bacteria diversity and arsenic mobilization in rock biofilm from an ancient gold and arsenic mine.

    Science.gov (United States)

    Tomczyk-Żak, Karolina; Kaczanowski, Szymon; Drewniak, Łukasz; Dmoch, Łukasz; Sklodowska, Aleksandra; Zielenkiewicz, Urszula

    2013-09-01

    In this paper we characterize the biofilm community from an ancient Złoty Stok gold and arsenic mine. Bacterial diversity was examined using a culture-independent technique based on 16S rRNA gene amplification, cloning and sequencing. We show that unexpectedly the microbial diversity of this community was extremely high (more than 190 OTUs detected), with the most numerous members from Rhizobiales (α-Proteobacteria). Although the level of rock biofilm diversity was similar to the microbial mat community we have previously characterized in the same adit, its taxonomic composition was completely different. Detailed analysis of functional arrA and aioA genes, chemical properties of siderophores found in pore water as well as the biofilm chemical composition suggest that the biofilm community contributes to arsenic pollution of surrounding water in a biogeochemical cycle similar to the one observed in bacterial mats. To interpret our results concerning the biological arsenic cycle, we applied the theory of ecological pyramids of Charles Elton. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Transient and permanent changes in DNA methylation patterns in inorganic arsenic-mediated epithelial-to-mesenchymal transition.

    Science.gov (United States)

    Eckstein, Meredith; Rea, Matthew; Fondufe-Mittendorf, Yvonne N

    2017-09-15

    Chronic low dose inorganic arsenic exposure causes cells to take on an epithelial-to-mesenchymal phenotype, which is a crucial process in carcinogenesis. Inorganic arsenic is not a mutagen and thus epigenetic alterations have been implicated in this process. Indeed, during the epithelial-to-mesenchymal transition, morphologic changes to cells correlate with changes in chromatin structure and gene expression, ultimately driving this process. However, studies on the effects of inorganic arsenic exposure/withdrawal on the epithelial-to-mesenchymal transition and the impact of epigenetic alterations in this process are limited. In this study we used high-resolution microarray analysis to measure the changes in DNA methylation in cells undergoing inorganic arsenic-induced epithelial-to-mesenchymal transition, and on the reversal of this process, after removal of the inorganic arsenic exposure. We found that cells exposed to chronic, low-dose inorganic arsenic exposure showed 30,530 sites were differentially methylated, and with inorganic arsenic withdrawal several differential methylated sites were reversed, albeit not completely. Furthermore, these changes in DNA methylation mainly correlated with changes in gene expression at most sites tested but not at all. This study suggests that DNA methylation changes on gene expression are not clear-cut and provide a platform to begin to uncover the relationship between DNA methylation and gene expression, specifically within the context of inorganic arsenic treatment. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  14. The DNA repair gene APE1 T1349G polymorphism and risk of gastric cancer in a Chinese population.

    Directory of Open Access Journals (Sweden)

    Dongying Gu

    Full Text Available BACKGROUND: Apurinic/apyrimidinic endonuclease 1 (APE1 has a central role in the repair of apurinic apyrimidic sites through both its endonuclease and its phosphodiesterase activities. A common APE1 polymorphism, T1349G (rs3136820, was previously shown to be associated with the risk of cancers. OBJECTIVE: We hypothesized that the APE1 T1349G polymorphism is also associated with risk of gastric cancer. METHODS: In a hospital-based case-control study of 338 case patients with newly diagnosed gastric cancer and 362 cancer-free controls frequency-matched by age and sex, we genotyped the T1349G polymorphism and assessed its associations with risk of gastric cancer. RESULTS: Compared with the APE1 TT genotype, individuals with the variant TG/GG genotypes had a significantly increased risk of gastric cancer (odds ratio = 1.69, 95% confidence interval = 1.19-2.40, which was more pronounced among subgroups of aged ≤ 60 years, male, ever smokers, and ever drinkers. Further analyses revealed that the variant genotypes were associated with an increased risk for diffuse-type, low depth of tumor infiltration (T1 and T2, and lymph node metastasis gastric cancer. CONCLUSIONS: The APE1 T1349G polymorphism may be a marker for the development of gastric cancer in the Chinese population. Larger studies are required to validate these findings in diverse populations.

  15. Autotrophic microbial arsenotrophy in arsenic-rich soda lakes

    Science.gov (United States)

    Oremland, Ronald S.; Saltikov, Chad W.; Stolz, John F.; Hollibaugh, James T.

    2017-01-01

    A number of prokaryotes are capable of employing arsenic oxy-anions as either electron acceptors [arsenate; As(V)] or electron donors [arsenite; As(III)] to sustain arsenic-dependent growth (‘arsenotrophy’). A subset of these microorganisms function as either chemoautotrophs or photoautotrophs, whereby they gain sufficient energy from their redox metabolism of arsenic to completely satisfy their carbon needs for growth by autotrophy, that is the fixation of inorganic carbon (e.g. HCO3−) into their biomass. Here we review what has been learned of these processes by investigations we have undertaken in three soda lakes of the western USA and from the physiological characterizations of the relevant bacteria, which include the critical genes involved, such as respiratory arsenate reductase (arrA) and the discovery of its arsenite-oxidizing counterpart (arxA). When possible, we refer to instances of similar process occurring in other, less extreme ecosystems and by microbes other than haloalkaliphiles.

  16. Pharmacogenetic Study in Rectal Cancer Patients Treated With Preoperative Chemoradiotherapy: Polymorphisms in Thymidylate Synthase, Epidermal Growth Factor Receptor, GSTP1, and DNA Repair Genes

    Energy Technology Data Exchange (ETDEWEB)

    Paez, David, E-mail: dpaez@santpau.cat [Department of Medical Oncology, Hospital de la Santa Creu i Sant Pau, Universitat Autonoma de Barcelona, Barcelona (Spain); Salazar, Juliana; Pare, Laia [Centre for Biomedical Network Research on Rare Diseases, Barcelona (Spain); Department of Genetics, Hospital de la Santa Creu i Sant Pau, Universitat Autonoma de Barcelona, Barcelona (Spain); Pertriz, Lourdes [Department of Radiotherapy, Hospital de la Santa Creu i Sant Pau, Universitat Autonoma de Barcelona, Barcelona (Spain); Targarona, Eduardo [Department of Surgery, Hospital de la Santa Creu i Sant Pau, Universitat Autonoma de Barcelona, Barcelona (Spain); Rio, Elisabeth del [Centre for Biomedical Network Research on Rare Diseases, Barcelona (Spain); Department of Genetics, Hospital de la Santa Creu i Sant Pau, Universitat Autonoma de Barcelona, Barcelona (Spain); Barnadas, Agusti; Marcuello, Eugenio [Department of Medical Oncology, Hospital de la Santa Creu i Sant Pau, Universitat Autonoma de Barcelona, Barcelona (Spain); Baiget, Montserrat [Centre for Biomedical Network Research on Rare Diseases, Barcelona (Spain); Department of Genetics, Hospital de la Santa Creu i Sant Pau, Universitat Autonoma de Barcelona, Barcelona (Spain)

    2011-12-01

    Purpose: Several studies have been performed to evaluate the usefulness of neoadjuvant treatment using oxaliplatin and fluoropyrimidines for locally advanced rectal cancer. However, preoperative biomarkers of outcome are lacking. We studied the polymorphisms in thymidylate synthase, epidermal growth factor receptor, glutathione S-transferase pi 1 (GSTP1), and several DNA repair genes to evaluate their usefulness as pharmacogenetic markers in a cohort of 128 rectal cancer patients treated with preoperative chemoradiotherapy. Methods and Materials: Blood samples were obtained from 128 patients with Stage II-III rectal cancer. DNA was extracted from the peripheral blood nucleated cells, and the genotypes were analyzed by polymerase chain reaction amplification and automated sequencing techniques or using a 48.48 dynamic array on the BioMark system. The germline polymorphisms studied were thymidylate synthase, (VNTR/5 Prime UTR, 2R G>C single nucleotide polymorphism [SNP], 3R G>C SNP), epidermal growth factor receptor (Arg497Lys), GSTP1 (Ile105val), excision repair cross-complementing 1 (Asn118Asn, 8092C>A, 19716G>C), X-ray repair cross-complementing group 1 (XRCC1) (Arg194Trp, Arg280His, Arg399Gln), and xeroderma pigmentosum group D (Lys751Gln). The pathologic response, pathologic regression, progression-free survival, and overall survival were evaluated according to each genotype. Results: The Asterisk-Operator 3/ Asterisk-Operator 3 thymidylate synthase genotype was associated with a greater response rate (pathologic complete remission and microfoci residual tumor, 59% in Asterisk-Operator 3/ Asterisk-Operator 3 vs. 35% in Asterisk-Operator 2/ Asterisk-Operator 2 and Asterisk-Operator 2/ Asterisk-Operator 3; p = .013). For the thymidylate synthase genotype, the median progression-free survival was 103 months for the Asterisk-Operator 3/ Asterisk-Operator 3 patients and 84 months for the Asterisk-Operator 2/ Asterisk-Operator 2 and Asterisk-Operator 2/ Asterisk

  17. Pharmacogenetic study in rectal cancer patients treated with preoperative chemoradiotherapy: polymorphisms in thymidylate synthase, epidermal growth factor receptor, GSTP1, and DNA repair genes.

    Science.gov (United States)

    Páez, David; Salazar, Juliana; Paré, Laia; Pertriz, Lourdes; Targarona, Eduardo; del Rio, Elisabeth; Barnadas, Agusti; Marcuello, Eugenio; Baiget, Montserrat

    2011-12-01

    Several studies have been performed to evaluate the usefulness of neoadjuvant treatment using oxaliplatin and fluoropyrimidines for locally advanced rectal cancer. However, preoperative biomarkers of outcome are lacking. We studied the polymorphisms in thymidylate synthase, epidermal growth factor receptor, glutathione S-transferase pi 1 (GSTP1), and several DNA repair genes to evaluate their usefulness as pharmacogenetic markers in a cohort of 128 rectal cancer patients treated with preoperative chemoradiotherapy. Blood samples were obtained from 128 patients with Stage II-III rectal cancer. DNA was extracted from the peripheral blood nucleated cells, and the genotypes were analyzed by polymerase chain reaction amplification and automated sequencing techniques or using a 48.48 dynamic array on the BioMark system. The germline polymorphisms studied were thymidylate synthase, (VNTR/5'UTR, 2R G>C single nucleotide polymorphism [SNP], 3R G>C SNP), epidermal growth factor receptor (Arg497Lys), GSTP1 (Ile105val), excision repair cross-complementing 1 (Asn118Asn, 8092C>A, 19716G>C), X-ray repair cross-complementing group 1 (XRCC1) (Arg194Trp, Arg280His, Arg399Gln), and xeroderma pigmentosum group D (Lys751Gln). The pathologic response, pathologic regression, progression-free survival, and overall survival were evaluated according to each genotype. The ∗3/∗3 thymidylate synthase genotype was associated with a greater response rate (pathologic complete remission and microfoci residual tumor, 59% in ∗3/∗3 vs. 35% in ∗2/∗2 and ∗2/∗3; p=.013). For the thymidylate synthase genotype, the median progression-free survival was 103 months for the ∗3/∗3 patients and 84 months for the ∗2/∗2 and ∗2/∗3 patients (p=.039). For XRCC1 Arg399Gln SNP, the median progression-free survival was 101 months for the G/G, 78 months for the G/A, and 31 months for the A/A patients (p=.048). The thymidylate synthase genotype and XRCC1 Arg399Gln polymorphism might help to

  18. A polymorphism in the base excision repair gene PARP2 is associated with differential prognosis by chemotherapy among postmenopausal breast cancer patients.

    Science.gov (United States)

    Seibold, Petra; Schmezer, Peter; Behrens, Sabine; Michailidou, Kyriaki; Bolla, Manjeet K; Wang, Qin; Flesch-Janys, Dieter; Nevanlinna, Heli; Fagerholm, Rainer; Aittomäki, Kristiina; Blomqvist, Carl; Margolin, Sara; Mannermaa, Arto; Kataja, Vesa; Kosma, Veli-Matti; Hartikainen, Jaana M; Lambrechts, Diether; Wildiers, Hans; Kristensen, Vessela; Alnæs, Grethe Grenaker; Nord, Silje; Borresen-Dale, Anne-Lise; Hooning, Maartje J; Hollestelle, Antoinette; Jager, Agnes; Seynaeve, Caroline; Li, Jingmei; Liu, Jianjun; Humphreys, Keith; Dunning, Alison M; Rhenius, Valerie; Shah, Mitul; Kabisch, Maria; Torres, Diana; Ulmer, Hans-Ulrich; Hamann, Ute; Schildkraut, Joellen M; Purrington, Kristen S; Couch, Fergus J; Hall, Per; Pharoah, Paul; Easton, Doug F; Schmidt, Marjanka K; Chang-Claude, Jenny; Popanda, Odilia

    2015-12-16

    Personalized therapy considering clinical and genetic patient characteristics will further improve breast cancer survival. Two widely used treatments, chemotherapy and radiotherapy, can induce oxidative DNA damage and, if not repaired, cell death. Since base excision repair (BER) activity is specific for oxidative DNA damage, we hypothesized that germline genetic variation in this pathway will affect breast cancer-specific survival depending on treatment. We assessed in 1,408 postmenopausal breast cancer patients from the German MARIE study whether cancer specific survival after adjuvant chemotherapy, anthracycline chemotherapy, and radiotherapy is modulated by 127 Single Nucleotide Polymorphisms (SNPs) in 21 BER genes. For SNPs with interaction terms showing p<0.1 (likelihood ratio test) using multivariable Cox proportional hazard analyses, replication in 6,392 patients from nine studies of the Breast Cancer Association Consortium (BCAC) was performed. rs878156 in PARP2 showed a differential effect by chemotherapy (p=0.093) and was replicated in BCAC studies (p=0.009; combined analysis p=0.002). Compared to non-carriers, carriers of the variant G allele (minor allele frequency=0.07) showed better survival after chemotherapy (combined allelic hazard ratio (HR)=0.75, 95% 0.53-1.07) and poorer survival when not treated with chemotherapy (HR=1.42, 95% 1.08-1.85). A similar effect modification by rs878156 was observed for anthracycline-based chemotherapy in both MARIE and BCAC, with improved survival in carriers (combined allelic HR=0.73, 95% CI 0.40-1.32). None of the SNPs showed significant differential effects by radiotherapy. Our data suggest for the first time that a SNP in PARP2, rs878156, may together with other genetic variants modulate cancer specific survival in breast cancer patients depending on chemotherapy. These germline SNPs could contribute towards the design of predictive tests for breast cancer patients.

  19. Nuclear survivin and its relationship to DNA damage repair genes in non-small cell lung cancer investigated using tissue array.

    Directory of Open Access Journals (Sweden)

    Songliu Hu

    Full Text Available To investigate the predictive role and association of nuclear survivin and the DNA double-strand breaks repair genes in non-small cell lung cancer (NSCLC: DNA-dependent protein kinase catalytic subunit (DNA-PKcs, Ku heterodimeric regulatory complex 70-KD subunit (Ku70 and ataxia-telangiectasia mutated (ATM.The protein expression of nuclear survivin, DNA-PKcs, Ku70 and ATM were investigated using immunohistochemistry in tumors from 256 patients with surgically resected NSCLC. Furthermore, we analyzed the correlation between the expression of nuclear survivin, DNA-PKcs, Ku70 and ATM. Univariate and multivariate anal