Isolating human DNA repair genes using rodent-cell mutants

International Nuclear Information System (INIS)

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

1987-01-01

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

Expression of DNA repair genes in ovarian cancer samples: biological and clinical considerations.

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Ganzinelli, M; Mariani, P; Cattaneo, D; Fossati, R; Fruscio, R; Corso, S; Ricci, F; Broggini, M; Damia, G

2011-05-01

The purpose of this study was to investigate retrospectively the mRNA expression of genes involved in different DNA repair pathways implicated in processing platinum-induced damage in 171 chemotherapy-naïve ovarian tumours and correlate the expression of the different genes with clinical parameters. The expression of genes involved in DNA repair pathways (PARP1, ERCC1, XPA, XPF, XPG, BRCA1, FANCA, FANCC, FANCD2, FANCF and PolEta), and in DNA damage transduction (Chk1 and Claspin) was measured by RT-PCR in 13 stage I borderline and 77 stage I and 88 III ovarian carcinomas. ERCC1, XPA, XPF and XPG genes were significantly less expressed in stage III than in stage I carcinoma; BRCA1, FANCA, FANCC, FANCD2 gene expressions were low in borderline tumours, higher in stage I carcinomas and lower in stage III samples. High levels of ERCC1, XPA, FANCC, XPG and PolEta correlated with an increase in Overall Survival (OS) and Progression Free Survival (PFS), whilst high BRCA1 levels were associated with PFS on univariate analysis. With multivariate analyses no genes retained an association when adjusted by stage, grade and residual tumour. A tendency towards a better PFS was observed in patients with the highest level of ERCC1 and BRCA1 after platinum-based therapy than those given both platinum and taxol. The expression of DNA repair genes differed in borderline stage I, stage I and stage III ovarian carcinomas. The role of DNA repair genes in predicting the response in ovarian cancer patients seems far from being established. Copyright © 2010 Elsevier Ltd. All rights reserved.

DNA repair-related genes in sugarcane expressed sequence tags (ESTs

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R.M.A. Costa

2001-12-01

Full Text Available There is much interest in the identification and characterization of genes involved in DNA repair because of their importance in the maintenance of the genome integrity. The high level of conservation of DNA repair genes means that these genetic elements may be used in phylogenetic studies as a source of information on the genetic origin and evolution of species. The mechanisms by which damaged DNA is repaired are well understood in bacteria, yeast and mammals, but much remains to be learned as regards plants. We identified genes involved in DNA repair mechanisms in sugarcane using a similarity search of the Brazilian Sugarcane Expressed Sequence Tag (SUCEST database against known sequences deposited in other public databases (National Center of Biotechnology Information (NCBI database and the Munich Information Center for Protein Sequences (MIPS Arabidopsis thaliana database. This search revealed that most of the various proteins involved in DNA repair in sugarcane are similar to those found in other eukaryotes. However, we also identified certain intriguing features found only in plants, probably due to the independent evolution of this kingdom. The DNA repair mechanisms investigated include photoreactivation, base excision repair, nucleotide excision repair, mismatch repair, non-homologous end joining, homologous recombination repair and DNA lesion tolerance. We report the main differences found in the DNA repair machinery in plant cells as compared to other organisms. These differences point to potentially different strategies plants employ to deal with DNA damage, that deserve further investigation.A identificação e caracterização de genes envolvidos com reparo de DNA são de grande interesse, dada a sua importância na manutenção da integridade genômica. Além disso, a alta conservação dos genes de reparo de DNA faz com que possam ser utilizados como fonte de informação no que diz respeito à origem e evolução das esp

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

Cloning and characterization of human DNA repair genes

International Nuclear Information System (INIS)

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

1987-01-01

The isolation of two addition human genes that give efficient restoration of the repair defects in other CHO mutant lines is reported. The gene designated ERCC2 (Excision Repair Complementing Chinese hamster) corrects mutant UV5 from complementation group 1. They recently cloned this gene by first constructing a secondary transformant in which the human gene was shown to have become physically linked to the bacterial gpt dominant-marker gene by cotransfer in calcium phosphate precipitates in the primary transfection. Transformants expressing both genes were recovered by selecting for resistance to both UV radiation and mycophenolic acid. Using similar methods, the human gene that corrects CHO mutant EM9 was isolated in cosmids and named XRCC1 (X-ray Repair Complementing Chinese hamster). In this case, transformants were recovered by selecting for resistance to CldUrd, which kills EM9 very efficiently. In both genomic and cosmid transformants, the XRCC1 gene restored resistance to the normal range. DNA repair was studied using the kinetics of strand-break rejoining, which was measured after exposure to 137 Cs γ-rays

Gene activation of heavy ion treated bacillus subtilis 168 endospores during germination involved DNA-repair

International Nuclear Information System (INIS)

Moeller, R.; Berger, T.; Reitz, G.; Okayasu, Ryuichi

2006-01-01

This research project is aimed at correlating radiation effects induced DNA damage in Bacillus subtilis endospores with the linear energy transfer (LET) of the used radiation by investigating survival and gene activation after irradiation with high-LET particles. During the stationary growth phase Bacillus subtilis change their metabolic active state from the vegetative cells to the metabolic inactive but even more resistant endospores. If spores find optimal conditions, they could germinate and switch to the vegetative growth. With these outgrowth spores can and/or must repair the induced formed DNA damage. During germination spores lose their most resistance. In more detail, DNA repair and mutation induction events investigated will include the survivability, behaviour against specific antibiotics and their germination. DNA repair pattern will be detected during germination by using DNA microarrays, which contain the whole genome of Bacillus subtilis 168. (author)

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

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

2009-01-01

-induced biological consequences. Furthermore, eight non-DBS repair genes showed involvement in regulating DSB repair, indicating that successful DSB repair requires both DSB repair mechanisms and non-DSB repair systems.

Non-functional genes repaired at the RNA level.

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Burger, Gertraud

2016-01-01

Genomes and genes continuously evolve. Gene sequences undergo substitutions, deletions or nucleotide insertions; mobile genetic elements invade genomes and interleave in genes; chromosomes break, even within genes, and pieces reseal in reshuffled order. To maintain functional gene products and assure an organism's survival, two principal strategies are used - either repair of the gene itself or of its product. I will introduce common types of gene aberrations and how gene function is restored secondarily, and then focus on systematically fragmented genes found in a poorly studied protist group, the diplonemids. Expression of their broken genes involves restitching of pieces at the RNA-level, and substantial RNA editing, to compensate for point mutations. I will conclude with thoughts on how such a grotesquely unorthodox system may have evolved, and why this group of organisms persists and thrives since tens of millions of years. Copyright © 2016 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Detection and characterization of polymorphisms in XRCC DNA repair genes in human population

International Nuclear Information System (INIS)

Staynova, A.; Hadjidekova, V.; Savov, A.

2004-01-01

Human population is continuously exposed to low levels of ionizing radiation. The main contribution gives the exposure due to medical applications. Nevertheless, most of the damage induced is repaired shortly after exposure by cellular repair systems. The review is focused on the development and application of methods to estimate the character of polymorphisms in repair genes (XRCC1, APE1), involved in single strand breaks repair which is corresponding mainly to the repair of X-ray induced DNA damage. Since, DSB are major factor for chromosomal aberrations formation, the assays described in this review might be useful for the assessment of the radiation risk for human population. (authors)

The majority of inducible DNA repair genes in Mycobacterium tuberculosis are induced independently of RecA.

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Rand, Lucinda; Hinds, Jason; Springer, Burkhard; Sander, Peter; Buxton, Roger S; Davis, Elaine O

2003-11-01

In many species of bacteria most inducible DNA repair genes are regulated by LexA homologues and are dependent on RecA for induction. We have shown previously by analysing the induction of recA that two mechanisms for the induction of gene expression following DNA damage exist in Mycobacterium tuberculosis. Whereas one of these depends on RecA and LexA in the classical way, the other mechanism is independent of both of these proteins and induction occurs in the absence of RecA. Here we investigate the generality of each of these mechanisms by analysing the global response to DNA damage in both wild-type M. tuberculosis and a recA deletion strain of M. tuberculosis using microarrays. This revealed that the majority of the genes that were induced remained inducible in the recA mutant stain. Of particular note most of the inducible genes with known or predicted functions in DNA repair did not depend on recA for induction. Amongst these are genes involved in nucleotide excision repair, base excision repair, damage reversal and recombination. Thus, it appears that this novel mechanism of gene regulation is important for DNA repair in M. tuberculosis.

DNA repair gene polymorphisms in relation to chromosome aberration frequencies in retired radiation workers

International Nuclear Information System (INIS)

Wilding, Craig S.; Relton, Caroline L.; Rees, Gwen S.; Tarone, Robert E.; Whitehouse, Caroline A.; Tawn, E. Janet

2005-01-01

Polymorphic variation in DNA repair genes was examined in a group of retired workers from the British Nuclear Fuels plc facility at Sellafield in relation to previously determined translocation frequencies in peripheral blood lymphocytes. Variation at seven polymorphisms in four genes involved in the base excision repair (XRCC1 R194W, R399Q and a [AC] n microsatellite in the 3' UTR) and double strand break repair (XRCC3 T241M and a [AC] n microsatellite in intron 3 of XRCC3, XRCC4 I134T, and a GACTAn microsatellite located 120kb 5' of XRCC5) pathways was determined for 291 retired radiation workers who had received cumulative occupational external radiation doses of between 0 and 1873mSv. When the interaction between radiation dose and each DNA repair gene polymorphism was examined in relation to translocation frequency there was no evidence for any of the polymorphisms studied influencing the response to occupational exposure. A positive interaction observed between genotype (individuals with at least one allele >=20 repeat units) at a microsatellite locus in the XRCC3 gene and smoking status should be interpreted cautiously because interactions were investigated for seven polymorphisms and two exposures. Nonetheless, further research is warranted to examine whether this DNA repair gene variant might be associated with a sub-optimal repair response to smoking-induced DNA damage and hence an increased frequency of translocations

Genetic polymorphisms in 85 DNA repair genes and bladder cancer risk.

Science.gov (United States)

Michiels, Stefan; Laplanche, Agnès; Boulet, Thomas; Dessen, Philippe; Guillonneau, Bertrand; Méjean, Arnaud; Desgrandchamps, François; Lathrop, Mark; Sarasin, Alain; Benhamou, Simone

2009-05-01

Several defense mechanisms have been developed and maintained during the evolution to protect human cells against damage produced from exogenous or endogenous sources. We examined the associations between bladder cancer and a panel of 652 polymorphisms from 85 genes involved in maintenance of genetic stability [base excision repair, nucleotide excision repair, double-strand break repair (DSBR) and mismatch repair, as well as DNA synthesis and cell cycle regulation pathways] in 201 incident bladder cancer cases and 326 hospital controls. Score statistics were used to test differences in haplotype frequencies between cases and controls in an unconditional logistic regression model. To account for multiple testing, we associated to each P-value the expected proportion of false discoveries (q-value). Haplotype analysis revealed significant associations (P genes (POLB and FANCA) with an associated q-value of 24%. A permutation test was also used to determine whether, in each pathway analyzed, there are more variants whose allelic frequencies are different between cases and controls as compared with what would be expected by chance. Differences were found for cell cycle regulation (P = 0.02) and to a lesser extent for DSBR (P = 0.05) pathways. These results hint to a few potential candidate genes; however, our study was limited by the small sample size and therefore low statistical power to detect associations. It is anticipated that genome-wide association studies will open new perspectives for interpretation of the results of extensive candidate gene studies such as ours.

Dynamic regulation of cerebral DNA repair genes by psychological stress

DEFF Research Database (Denmark)

Forsberg, Kristin; Aalling, Nadia; Wörtwein, Gitta

2015-01-01

Neuronal genotoxic insults from oxidative stress constitute a putative molecular link between stress and depression on the one hand, and cognitive dysfunction and dementia risk on the other. Oxidative modifications to DNA are repaired by specific enzymes; a process that plays a critical role...... restraint stress (6h/day) or daily handling (controls), and sacrificed after 1, 7 or 21 stress sessions. The mRNA expression of seven genes (Ogg1, Ape1, Ung1, Neil1, Xrcc1, Ercc1, Nudt1) involved in the repair of oxidatively damaged DNA was determined by quantitative real time polymerase chain reaction...

Epigenetic changes of DNA repair genes in cancer.

Science.gov (United States)

Lahtz, Christoph; Pfeifer, Gerd P

2011-02-01

'Every Hour Hurts, The Last One Kills'. That is an old saying about getting old. Every day, thousands of DNA damaging events take place in each cell of our body, but efficient DNA repair systems have evolved to prevent that. However, our DNA repair system and that of most other organisms are not as perfect as that of Deinococcus radiodurans, for example, which is able to repair massive amounts of DNA damage at one time. In many instances, accumulation of DNA damage has been linked to cancer, and genetic deficiencies in specific DNA repair genes are associated with tumor-prone phenotypes. In addition to mutations, which can be either inherited or somatically acquired, epigenetic silencing of DNA repair genes may promote tumorigenesis. This review will summarize current knowledge of the epigenetic inactivation of different DNA repair components in human cancer.

Early passage bone marrow stromal cells express genes involved in nervous system development supporting their relevance for neural repair

NARCIS (Netherlands)

Nandoe Tewarie, R.D.S.; Bossers, K.; Ritfeld, G.J.; Blits, B.; Grotenhuis, J.A.; Verhaagen, J.; Oudega, M.

2011-01-01

PURPOSE: The assessment of the capacity of bone marrow stromal cells (BMSC) to repair the nervous system using gene expression profiling. The evaluation of effects of long-term culturing on the gene expression profile of BMSC. METHODS: Fourty four k whole genome rat microarrays were used to study

TLR9 agonists oppositely modulate DNA repair genes in tumor versus immune cells and enhance chemotherapy effects.

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Sommariva, Michele; De Cecco, Loris; De Cesare, Michelandrea; Sfondrini, Lucia; Ménard, Sylvie; Melani, Cecilia; Delia, Domenico; Zaffaroni, Nadia; Pratesi, Graziella; Uva, Valentina; Tagliabue, Elda; Balsari, Andrea

2011-10-15

Synthetic oligodeoxynucleotides expressing CpG motifs (CpG-ODN) are a Toll-like receptor 9 (TLR9) agonist that can enhance the antitumor activity of DNA-damaging chemotherapy and radiation therapy in preclinical mouse models. We hypothesized that the success of these combinations is related to the ability of CpG-ODN to modulate genes involved in DNA repair. We conducted an in silico analysis of genes implicated in DNA repair in data sets obtained from murine colon carcinoma cells in mice injected intratumorally with CpG-ODN and from splenocytes in mice treated intraperitoneally with CpG-ODN. CpG-ODN treatment caused downregulation of DNA repair genes in tumors. Microarray analyses of human IGROV-1 ovarian carcinoma xenografts in mice treated intraperitoneally with CpG-ODN confirmed in silico findings. When combined with the DNA-damaging drug cisplatin, CpG-ODN significantly increased the life span of mice compared with individual treatments. In contrast, CpG-ODN led to an upregulation of genes involved in DNA repair in immune cells. Cisplatin-treated patients with ovarian carcinoma as well as anthracycline-treated patients with breast cancer who are classified as "CpG-like" for the level of expression of CpG-ODN modulated DNA repair genes have a better outcome than patients classified as "CpG-untreated-like," indicating the relevance of these genes in the tumor cell response to DNA-damaging drugs. Taken together, the findings provide evidence that the tumor microenvironment can sensitize cancer cells to DNA-damaging chemotherapy, thereby expanding the benefits of CpG-ODN therapy beyond induction of a strong immune response.

Zebrafish: swimming towards a role for fanconi genes in DNA repair.

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Scata, Kimberly A; El-Deiry, Wafik S

2004-06-01

The zebrafish, Danio rerio, has become a favorite model organism for geneticists and developmental biologists. Recently cancer biologists have turned to this tiny fish to help them unravel the mysteries of conserved pathways such as the Fanconi Anemia (FA) pathway. Although a relatively rare disease, the genes involved in FA are part of a large network of DNA damage response/repair genes. Liu and colleagues have recapitulated some of the clinical manifestations of human FA by knocking down the zebrafish FANC-D2 gene thereby providing a new model for probing the underlying causes of these phenotypes.

Genetic polymorphisms in homologous recombination repair genes in healthy Slovenian population and their influence on DNA damage

International Nuclear Information System (INIS)

Goricar, Katja; Erculj, Nina; Zadel, Maja; Dolzan, Vita

2012-01-01

Homologous recombination (HR) repair is an important mechanism involved in repairing double-strand breaks in DNA and for maintaining genomic stability. Polymorphisms in genes coding for enzymes involved in this pathway may influence the capacity for DNA repair. The aim of this study was to select tag single nucleotide polymorphisms (SNPs) in specific genes involved in HR repair, to determine their allele frequencies in a healthy Slovenian population and their influence on DNA damage detected with comet assay. In total 373 individuals were genotyped for nine tag SNPs in three genes: XRCC3 722C>T, XRCC3 -316A>G, RAD51 -98G>C, RAD51 -61G>T, RAD51 1522T>G, NBS1 553G>C, NBS1 1197A>G, NBS1 37117C>T and NBS1 3474A>C using competitive allele-specific amplification (KASPar assay). Comet assay was performed in a subgroup of 26 individuals to determine the influence of selected SNPs on DNA damage. We observed that age significantly affected genotype frequencies distribution of XRCC3 -316A>G (P = 0.039) in healthy male blood donors. XRCC3 722C>T (P = 0.005), RAD51 -61G>T (P = 0.023) and NBS1 553G>C (P = 0.008) had a statistically significant influence on DNA damage. XRCC3 722C>T, RAD51 -61G>T and NBS1 553G>C polymorphisms significantly affect the repair of damaged DNA and may be of clinical importance as they are common in Slovenian population

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

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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.

Identification of genes and proteins involved in excision repair of human cells

International Nuclear Information System (INIS)

Hoeijmakers, J.H.J.; Westerveld, A.; Van Duin, M.; Vermeulen, W.; Odijk, H.; De Wit, J.; Bootsma, D.

1986-01-01

The autosomal, recessive disorder xeroderma pigmentosum (XP) is characterized by extreme sensitivity of the skin to sun exposure and prediposition to skin cancer. The basic defect in most XP patients is thought to reside in an inefficient removal of UV-induced lesions in the DNA by excision repair. The biochemical complexity of this process is amply illustrated by the fact that so far nine complementary groups within this syndrome have been identified. Despite extensive research, none of these genes or proteins involved have been isolated. Using a microinjection assay system the authors identified components in crude cell extracts that transiently correct the defect in (injected) fibroblasts of all excision-deficient XP complementation groups, as indicated by temporary restoration of UV-induced unscheduled DNA synthesis. This correction is complementation group specific, since it is only found when extracts from complementing XP cells are injected. After incubation of extracts with proteinase K the XP-A and KP-G correcting activities were lost, indicating that the complementation is due to proteins. The XP-A correcting protein was found to precipitate between 30 and 60% ammonium sulfate saturation. Furthermore this protein binds to DEAE-cellulose and to (UV-irradiated) double-strand (ds) DNA attached to cellulose. The latter affinity chromatography step allows a considerable purification, since less than 1% of the proteins applied to such columns is retained. It has to be established whether the XP-A correcting proteins binds by itself or via other proteins to the UV-irradiated DNA and whether it also binds to nonirradiated (ds or ss) DNA. Similar experiments with the XP-G correcting protein are in progress

Identification of DNA repair genes in the human genome

International Nuclear Information System (INIS)

Hoeijmakers, J.H.J.; van Duin, M.; Westerveld, A.; Yasui, A.; Bootsma, D.

1986-01-01

To identify human DNA repair genes we have transfected human genomic DNA ligated to a dominant marker to excision repair deficient xeroderma pigmentosum (XP) and CHO cells. This resulted in the cloning of a human gene, ERCC-1, that complements the defect of a UV- and mitomycin-C sensitive CHO mutant 43-3B. The ERCC-1 gene has a size of 15 kb, consists of 10 exons and is located in the region 19q13.2-q13.3. Its primary transcript is processed into two mRNAs by alternative splicing of an internal coding exon. One of these transcripts encodes a polypeptide of 297 aminoacids. A putative DNA binding protein domain and nuclear location signal could be identified. Significant AA-homology is found between ERCC-1 and the yeast excision repair gene RAD10. 58 references, 6 figures, 1 table

DNA repair in Mycobacterium tuberculosis revisited.

Science.gov (United States)

Dos Vultos, Tiago; Mestre, Olga; Tonjum, Tone; Gicquel, Brigitte

2009-05-01

Our understanding of Mycobacterium tuberculosis DNA repair mechanisms is still poor compared with that of other bacterial organisms. However, the publication of the first complete M. tuberculosis genome sequence 10 years ago boosted the study of DNA repair systems in this organism. A first step in the elucidation of M. tuberculosis DNA repair mechanisms was taken by Mizrahi and Andersen, who identified homologs of genes involved in the reversal or repair of DNA damage in Escherichia coli and related organisms. Genes required for nucleotide excision repair, base excision repair, recombination, and SOS repair and mutagenesis were identified. Notably, no homologs of genes involved in mismatch repair were identified. Novel characteristics of the M. tuberculosis DNA repair machinery have been found over the last decade, such as nonhomologous end joining, the presence of Mpg, ERCC3 and Hlr - proteins previously presumed to be produced exclusively in mammalian cells - and the recently discovered bifunctional dCTP deaminase:dUTPase. The study of these systems is important to develop therapeutic agents that can counteract M. tuberculosis evolutionary changes and to prevent adaptive events resulting in antibiotic resistance. This review summarizes our current understanding of the M. tuberculosis DNA repair system.

The involvement of DNA repair genes in the hypoxia-dependent NLCQ-1 (NSC 709257) toxicity and its synergistic interaction with cisplatin or melphalan

International Nuclear Information System (INIS)

Papadopoulou, M.V.; Xue, C.-J.; Bloomer, W.D.

2003-01-01

4-[3-(2-Nitro-1-imidazolyl)-propylamino]-7-chloro-quinoline hydrochloride (NLCQ-1) is a weakly DNA-intercalating hypoxia selective cytotoxin, which synergistically enhances the antitumor effect of several chemotherapeutic agents or radiation against mouse tumors or human xenografts. Synergy with melphalan (L-PAM) or cisplatin (cisPt) requires hypoxic pre-exposure of cells to NLCQ-1 or, in mice, administration of NLCQ-1 about 1 h before L-PAM or cisPt. This suggests that NLCQ-1 may cause DNA lesions upon reductive metabolism. To indirectly identify such lesions, rodent cell lines defective in specific DNA repair genes (EM9 and UV41) and their repair-proficient parental AA8, were exposed to NLCQ-1 alone and in combination with L-PAM or cisPt under hypoxic/aerobic conditions and appropriate routes, and assessed for clonogenicity. Selected comparisons with tirapazamine (TPZ) were also performed. DNA ssbs were identified by using the alkaline comet assay. Synergism was assessed by isobologramic analysis. EM9, which lack the functional XRCC1 gene and are unable to efficiently repair DNA ssbs, were 3.7x and 4.5x more sensitive to NLCQ-1 and TPZ, respectively, than the parental AA8 cells. Similarly, UV41, which are defective in the ERCC4/XPF gene and thus, hypersensitive to DNA cross-linking agents, were 4.1x more sensitive than AA8 cells to NLCQ-1. Equitoxic concentrations of NLCQ-1 and TPZ gave similar numbers of ssbs in AA8 and EM9 cells exposed to each compound for 1 h under hypoxic conditions. In combination with L-PAM or cisPt, synergy was observed in AA8 but not in EM9 or UV41 cells, with either NLCQ-1 or TPZ. These results suggest that NLCQ-1 is involved in the formation of DNA ssbs and interstrand crosslinks, with the latter being most likely responsible for NLCQ-1 hypoxic toxicity. The synergistic interaction of NLCQ-1 with L-PAM or cisPt is probably due to an enhancement in the L-PAM/cisPt-induced DNA interstrand crosslinks, possibly as a result of an inhibited

DNA Glycosylases Involved in Base Excision Repair May Be Associated with Cancer Risk in BRCA1 and BRCA2 Mutation Carriers

NARCIS (Netherlands)

A. Osorio (Ana); R.L. Milne (Roger); K.B. Kuchenbaecker (Karoline); T. Vaclová (Tereza); G. Pita (Guillermo); R. Alonso (Rosario); P. Peterlongo (Paolo); I. Blanco (Ignacio); M. de La Hoya (Miguel); M. Durán (Mercedes); O. Díez (Orland); T. Ramon Y Cajal; I. Konstantopoulou (I.); C. Martínez-Bouzas (Cristina); R. Andrés Conejero (Raquel); P. Soucy (Penny); L. McGuffog (Lesley); D. Barrowdale (Daniel); A. Lee (Andrew); B. Arver (Brita Wasteson); J. Rantala (Johanna); N. Loman (Niklas); H. Ehrencrona (Hans); O.I. Olopade (Olofunmilayo); M.S. Beattie (Mary); S.M. Domchek (Susan); K.L. Nathanson (Katherine); R. Rebbeck (Timothy); B.K. Arun (Banu); B.Y. Karlan (Beth); C.S. Walsh (Christine); K.J. Lester (Kathryn); E.M. John (Esther); A.S. Whittemore (Alice); M.B. Daly (Mary); M.C. Southey (Melissa); J.L. Hopper (John); M.-B. Terry (Mary-Beth); S.S. Buys (Saundra); R. Janavicius (Ramunas); C.M. Dorfling (Cecilia); E.J. van Rensburg (Elizabeth); L. Steele (Linda); S.L. Neuhausen (Susan); Y.C. Ding (Yuan); T.V.O. Hansen (Thomas); L. Jønson (Lars); B. Ejlertsen (Bent); A-M. Gerdes (Anne-Marie); J. Infante (Jon); B. Herráez (Belén); L.T. Moreno (Leticia Thais); J.N. Weitzel (Jeffrey); J. Herzog (Josef); K. Weeman (Kisa); S. Manoukian (Siranoush); B. Peissel (Bernard); D. Zaffaroni (D.); G. Scuvera (Giulietta); B. Bonnani (Bernardo); F. Mariette (F.); S. Volorio (Sara); A. Viel (Alessandra); L. Varesco (Liliana); L. Papi (Laura); L. Ottini (Laura); M.G. Tibiletti (Maria Grazia); P. Radice (Paolo); D. Yannoukakos (Drakoulis); J. Garber; S.D. Ellis (Steve); D. Frost (Debra); R. Platte (Radka); E. Fineberg (Elena); D.G. Evans (Gareth); F. Lalloo (Fiona); L. Izatt (Louise); R. Eeles (Rosalind); J.W. Adlard (Julian); R. Davidson (Rosemarie); T.J. Cole (Trevor); D. Eccles (Diana); J. Cook (Jackie); S.V. Hodgson (Shirley); C. Brewer (Carole); M. Tischkowitz (Marc); F. Douglas (Fiona); M.E. Porteous (Mary); L. Side (Lucy); L.J. Walker (Lisa); P.J. Morrison (Patrick); A. Donaldson (Alan); J. Kennedy (John); C. Foo (Claire); A.K. Godwin (Andrew); R.K. Schmutzler (Rita); B. Wapenschmidt (Barbara); K. Rhiem (Kerstin); C.W. Engel (Christoph); A. Meindl (Alfons); N. Ditsch (Nina); N. Arnold (Norbert); H. Plendl (Hansjoerg); D. Niederacher (Dieter); C. Sutter (Christian); S. Wang-Gohrke (Shan); D. Steinemann (Doris); S. Preisler-Adams (Sabine); K. Kast (Karin); R. Varon-Mateeva (Raymonda); P.A. Gehrig (Paola A.); D. Stoppa-Lyonnet (Dominique); O. Sinilnikova (Olga); S. Mazoyer (Sylvie); F. Damiola (Francesca); B. Poppe (Bruce); K. Claes (Kathleen); M. Piedmonte (Marion); K. Tucker (Kathryn); F.J. Backes (Floor); P.M. Rodríguez; W. Brewster (Wendy); K. Wakeley (Katie); T. Rutherford (Thomas); T. Caldes (Trinidad); H. Nevanlinna (Heli); K. Aittomäki (Kristiina); M.A. Rookus (Matti); T.A.M. van Os (Theo); L. van der Kolk (Lizet); J.L. de Lange (J.); E.J. Meijers-Heijboer (Hanne); A.H. van der Hout (Annemarie); C.J. van Asperen (Christi); E.B. Gómez García (Encarna); N. Hoogerbrugge (Nicoline); J.M. Collée (Margriet); C.H.M. van Deurzen (Carolien); R.B. van der Luijt (Rob); P. Devilee (Peter); E. Olah (Edith); C. Lazaro (Conxi); A. Teulé (A.); M. Menéndez (Mireia); A. Jakubowska (Anna); C. Cybulski (Cezary); J. Gronwald (Jacek); J. Lubinski (Jan); K. Durda (Katarzyna); K. Jaworska-Bieniek (Katarzyna); O.T. Johannson (Oskar); C. Maugard; M. Montagna (Marco); S. Tognazzo (Silvia); P.J. Teixeira; S. Healey (Sue); C. Olswold (Curtis); L. Guidugli (Lucia); N.M. Lindor (Noralane); S. Slager (Susan); C. Szabo (Csilla); J. Vijai (Joseph); M. Robson (Mark); N. Kauff (Noah); L. Zhang (Lingling); R. Rau-Murthy (Rohini); A. Fink-Retter (Anneliese); C.F. Singer (Christian); C. Rappaport (Christine); D. Geschwantler Kaulich (Daphne); G. Pfeiler (Georg); M.-K. Tea; A. Berger (Annemarie); C. Phelan (Catherine); M.H. Greene (Mark); P.L. Mai (Phuong); F. Lejbkowicz (Flavio); I.L. Andrulis (Irene); A.M. Mulligan (Anna Marie); G. Glendon (Gord); A.E. Toland (Amanda); S.E. Bojesen (Stig); I.S. Pedersen (Inge Sokilde); L. Sunde (Lone); M. Thomassen (Mads); T.A. Kruse (Torben); U.B. Jensen; E. Friedman (Eitan); Y. Laitman (Yael); S.P. Shimon (Shani Paluch); J. Simard (Jacques); D.F. Easton (Douglas); K. Offit (Kenneth); F.J. Couch (Fergus); G. Chenevix-Trench (Georgia); A.C. Antoniou (Antonis); J. Benítez (Javier)

2014-01-01

textabstractSingle Nucleotide Polymorphisms (SNPs) in genes involved in the DNA Base Excision Repair (BER) pathway could be associated with cancer risk in carriers of mutations in the high-penetrance susceptibility genes BRCA1 and BRCA2, given the relation of synthetic lethality that exists between

DNA glycosylases involved in base excision repair may be associated with cancer risk in BRCA1 and BRCA2 mutation carriers

NARCIS (Netherlands)

Osorio, A.; Milne, R.L.; Kuchenbaecker, K.; Vaclova, T.; Pita, G.; Alonso, R.; Peterlongo, P.; Blanco, I.; Hoya, M. de la; Duran, M.; Diez, O.; Ramon, Y.C.T.; Konstantopoulou, I.; Martinez-Bouzas, C.; Conejero, R. Andres; Soucy, P.; McGuffog, L.; Barrowdale, D.; Lee, A.; Swe, B.; Arver, B.; Rantala, J.; Loman, N.; Ehrencrona, H.; Olopade, O.I.; Beattie, M.S.; Domchek, S.M.; Nathanson, K.; Rebbeck, T.R.; Arun, B.K.; Karlan, B.Y.; Walsh, C.; Lester, J.; John, E.M.; Whittemore, A.S.; Daly, M.B.; Southey, M.; Hopper, J.; Terry, M.B.; Buys, S.S.; Janavicius, R.; Dorfling, C.M.; Rensburg, E.J. van; Steele, L.; Neuhausen, S.L.; Ding, Y.C.; Hansen, T.V.; Jonson, L.; Ejlertsen, B.; Gerdes, A.M.; Infante, M.; Herraez, B.; Moreno, L.T.; Weitzel, J.N.; Herzog, J.; Weeman, K.; Manoukian, S.; Peissel, B.; Zaffaroni, D.; Scuvera, G.; Bonanni, B.; Mariette, F.; Volorio, S.; Viel, A.; Varesco, L.; Papi, L.; Ottini, L.; Tibiletti, M.G.; Radice, P.; Yannoukakos, D.; Garber, J.; Ellis, S.; Frost, D.; Platte, R.; Fineberg, E.; Evans, G.; Lalloo, F.; Izatt, L.; Eeles, R.; Adlard, J.; Davidson, R.; Cole, T.; Eccles, D.; Cook, J; Hodgson, S.; Brewer, C.; Tischkowitz, M.; Douglas, F.; Porteous, M.; Side, L.; Walker, L.; Morrison, P.; Donaldson, A.; Kennedy, J.; Foo, C.; Godwin, A.K.; Schmutzler, R.K.; Wappenschmidt, B.; Rhiem, K.; Engel, C.; Hoogerbrugge-van der Linden, N.; et al.,

2014-01-01

Single Nucleotide Polymorphisms (SNPs) in genes involved in the DNA Base Excision Repair (BER) pathway could be associated with cancer risk in carriers of mutations in the high-penetrance susceptibility genes BRCA1 and BRCA2, given the relation of synthetic lethality that exists between one of the

DNA repair in human cells: Methods for the determination of calmodulin involvement

International Nuclear Information System (INIS)

Charp, P.A.

1987-01-01

Exposure of DNA to either physical or chemical agents can result in the formation of a number of different lesions which must be repaired enzymatically in order for DNA to carry on normal replication and transcription. In most cases, the enzymes involved in this repair of damaged DNA include endonucleases, exonucleases, glycosylases, polymerases, and ligases. Each group of enzymes is involved in precise steps in DNA repair. Exposure to physical agents such as ultraviolet light (UV) at a wavelength of 254 nm is repaired by two distinct and different mechanisms. One mode of enzymatic repair of pyrimidine dimers is accomplished in situ by photoreactivation of UV-induced pyrimidine dimers by photoreactivating light. The second mode of enzymatic repair is the excision repair of pyrimidine dimers involving several different enzymes including endonuclease, exonuclease, and DNA ligase. A summary of the sequence of enzymatic steps involved is shown. It has been observed that specific drugs which bind to and alter the action of calmodulin in cells block DNA synthesis. This suggests that calmodulin may play a role both in normal DNA replication and repair. Others using an indirect method measuring the degree of DNA nucleoid sedimentation, showed that the specific anti-calmodulin agent W-13 slowed the rate of DNA repair. Others showed that DNA synthesis in T51B rat liver cells could be blocked with the addition of either chlorpromazine or trifluoperazine

Repair of DNA damage in the human metallothionein gene family

International Nuclear Information System (INIS)

Leadon, S.A.; Snowden, M.M.

1987-01-01

In order to distinguish enhanced repair of a sequence due to its transcriptional activity from enhanced repair due to chromatin alterations brought about by integration of a sequence into the genome, we have investigated the repair of damage both in endogenous genes and in cell lines that contain an integrated gene with an inducible promoter. The endogenous genes we are studying are the metallothioneins (MTs), a multigene family in man consisting of about 10-12 members. Cultured cells were exposed to 10-J/m 2 uv light and allowed to repair in the presence of bromodeoxyuridine. The DNA was then isolated, digested with Eco RI, and fully hybrid density DNA made by semiconservative synthesis was separated from unreplicated DNA by centrifugation in CsCl density gradients. Unreplicated, parental-density DNA was then reacted with a monoclonal antibody against bromouracil. 1 ref., 1 fig., 1 tab

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.

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.

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

International Nuclear Information System (INIS)

Chistiakov, Dimitry A.; Voronova, Natalia V.; Chistiakov, Pavel A.

2008-01-01

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

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

DNA repair mechanism in radioresistant bacteria

International Nuclear Information System (INIS)

Kitayama, Shigeru

1992-01-01

Many radiation resistant bacteria have been isolated from various sources which are not in high background field. Since Deinococcus radiodurans had been isolated first in 1956, studies on the mechanism for radioresistance were carried out mostly using this bacterium. DNA in this bacterium isn't protected against injury induced by not only ionizing radiation but also ultraviolet light. Therefore, DNA damages induced by various treatments are efficiently and accurately repaired in this cells. Damages in base and/or sugar in DNA are removed by endonucleases which, if not all, are synthesized during postirradiation incubation. Following the endonucleolytic cleavage the strand scissions in DNA are seemed to be rejoined by a process common for the repair of strand scissions induced by such as ionizing radiations. Induce protein(s) is also involved in this rejoining process of strand scissions. DNA repair genes were classified into three phenotypic groups. (1)Genes which are responsible for the endonucleolytic activities. (2) Genes involved in the rejoining of DNA strand scissions. (3) Genes which participate in genetic recombination and repair. Three genes belong to (1) and (2) were cloned onto approximately 1 kbp DNA fragments which base sequences have been determined. (author)

DNA repair mechanism in radioresistant bacteria

International Nuclear Information System (INIS)

Kitayama, Shigeru

1992-01-01

Many radiation resistant bacteria have been isolated from various sources which are not in high background field. Since Deinococcus radiodurans had been isolated first in 1956, the studies on the mechanism of radioresistance were mostly carried out using this bacterium. DNA in this bacterium isn't protected against injury induced by not only ionizing radiation but also ultraviolet light. Therefore, DNA damages induced by various treatments are efficiently and accurately repaired in this cells. Damages in base and/or sugar in DNA are removed by endonucleases which, if not all, are synthesized during postirradiation incubation. Following the endonucleolytic cleavage the strand scissions in DNA are seemed to be rejoined by a process common for the repair of strand scissions induced by such as ionizing radiations. Induce protein(s) is also involved in this rejoining process of strand scissions. DNA repair genes were classified into three phenotypic groups. (1) Genes which are responsible for the endonucleolytic activities. (2) Genes involved in the rejoining of DNA strand scissions. (3) Genes which participate in genetic recombination and repair. Three genes belong to (1) and (2) were cloned onto approximately 1 kbp DNA fragments which base sequences have been determined. (author)

Nrf2 facilitates repair of radiation induced DNA damage through homologous recombination repair pathway in a ROS independent manner in cancer cells

Energy Technology Data Exchange (ETDEWEB)

Jayakumar, Sundarraj; Pal, Debojyoti; Sandur, Santosh K., E-mail: sskumar@barc.gov.in

2015-09-15

Highlights: • Nrf2 inhibition in A549 cells led to attenuated DNA repair and radiosensitization. • Influence of Nrf2 on DNA repair is not linked to its antioxidant function. • Nrf2 influences DNA repair through homologous recombination (HR) repair pathway. • Many genes involved in HR pathway show ARE sequences in their upstream region. - Abstract: Nrf2 is a redox sensitive transcription factor that is involved in the co-ordinated transcription of genes involved in redox homeostasis. But the role of Nrf2 in DNA repair is not investigated in detail. We have employed A549 and MCF7 cells to study the role of Nrf2 on DNA repair by inhibiting Nrf2 using all-trans retinoic acid (ATRA) or by knock down approach prior to radiation exposure (4 Gy). DNA damage and repair analysis was studied by γH2AX foci formation and comet assay. Results suggested that the inhibition of Nrf2 in A549 or MCF7 cells led to significant slowdown in DNA repair as compared to respective radiation controls. The persistence of residual DNA damage even in the presence of free radical scavenger N-acetyl cysteine, suggested that the influence of Nrf2 on DNA repair was not linked to its antioxidant functions. Further, its influence on non-homologous end joining repair pathway was studied by inhibiting both Nrf2 and DNA-PK together. This led to synergistic reduction of survival fraction, indicating that Nrf2 may not be influencing the NHEJ pathway. To investigate the role of homologous recombination repair (HR) pathway, RAD51 foci formation was monitored. There was a significant reduction in the foci formation in cells treated with ATRA or shRNA against Nrf2 as compared to their respective radiation controls. Further, Nrf2 inhibition led to significant reduction in mRNA levels of RAD51. BLAST analysis was also performed on upstream regions of DNA repair genes to identify antioxidant response element and found that many repair genes that are involved in HR pathway may be regulated by Nrf2

Gene promoter methylation and DNA repair capacity in monozygotic twins with discordant smoking habits.

Science.gov (United States)

Ottini, Laura; Rizzolo, Piera; Siniscalchi, Ester; Zijno, Andrea; Silvestri, Valentina; Crebelli, Riccardo; Marcon, Francesca

2015-02-01

The influence of DNA repair capacity, plasma nutrients and tobacco smoke exposure on DNA methylation was investigated in blood cells of twenty-one couples of monozygotic twins with discordant smoking habits. All study subjects had previously been characterized for mutagen sensitivity with challenge assays with ionizing radiation in peripheral blood lymphocytes. Plasma levels of folic acid, vitamin B12 and homocysteine were also available from a previous investigation. In this work DNA methylation in the promoter region of a panel of ten genes involved in cell cycle control, differentiation, apoptosis and DNA repair (p16, FHIT, RAR, CDH1, DAPK1, hTERT, RASSF1A, MGMT, BRCA1 and PALB2) was assessed in the same batches of cells isolated for previous studies, using the methylation-sensitive high-resolution melting technique. Fairly similar profiles of gene promoter methylation were observed within co-twins compared to unrelated subjects (p= 1.23 × 10(-7)), with no significant difference related to smoking habits (p = 0.23). In a regression analysis the methylation index of study subjects, used as synthetic descriptor of overall promoter methylation, displayed a significant inverse correlation with radiation-induced micronuclei (p = 0.021) and plasma folic acid level (p = 0.007) both in smokers and in non-smokers. The observed association between repair of radiation-induced DNA damage and promoter methylation suggests the involvement of the DNA repair machinery in DNA modification. Data also highlight the possible modulating effect of folate deficiency on DNA methylation and the strong influence of familiarity on the individual epigenetic profile. Copyright © 2015 Elsevier B.V. All rights reserved.

Low intensity infrared laser affects expression of oxidative DNA repair genes in mitochondria and nucleus

International Nuclear Information System (INIS)

Fonseca, A S; Magalhães, L A G; Mencalha, A L; Geller, M; Paoli, F

2014-01-01

Practical properties and physical characteristics of low intensity lasers have made possible their application to treat soft tissue diseases. Excitation of intracellular chromophores by red and infrared radiation at low energy fluences with increase of mitochondrial metabolism is the basis of the biostimulation effect but free radicals can be produced. DNA lesions induced by free radicals are repaired by the base excision repair pathway. In this work, we evaluate the expression of POLγ and APEX2 genes related to repair of mitochondrial and nuclear DNA, respectively. Skin and muscle tissue of Wistar rats were exposed to low intensity infrared laser at different fluences. One hour and 24 hours after laser exposure, tissue samples were withdrawn for total RNA extraction, cDNA synthesis, and evaluation of POLγ and APEX2 mRNA expression by real time quantitative polymerase chain reaction. Skin and muscle tissue of Wistar rats exposed to laser radiation show different expression of POLγ and APEX2 mRNA depending of the fluence and time after exposure. Our study suggests that a low intensity infrared laser affects expression of genes involved in repair of oxidative lesions in mitochondrial and nuclear DNA. (paper)

Synergistic interactions between RAD5, RAD16, and RAD54, three partially homologous yeast DNA repair genes each in a different repair pathway

International Nuclear Information System (INIS)

Glassner, B.J.; Mortimer, R.K.

1994-01-01

Considerable homology has recently been noted between the proteins encoded by the RAD5, RAD16 and RAD54 genes of Saccharomyces cerevisiae. These genes are members of the RAD6, RAD3 and RAD50 epistasis groups, respectively, which correspond to the three major DNA repair pathways in yeast. These proteins also share homology with other eucaryotic proteins, including those encoded by SNF2 and MO1 of yeast, brahma and lodestar of Drosophila and the human ERCC6 gene. The homology shares features with known helicases, suggesting a newly identified helicase subfamily. We have constructed a series of congenic single-, double- and triple-deletion mutants involving RAD5, RAD16 and RAD54 to examine the interactions between these genes. Each deletion mutation alone has only a moderate effect on survival after exposure to UV radiation. Each pairwise-double mutant exhibits marked synergism. The triple-deletion mutant displays further synergism. These results confirm the assignment of the RAD54 gene to the RAD50 epistasis group and suggest that the RAD16 gene plays a larger role in DNA repair after exposure to UV radiation than has been suggested previously. Additionally, the proteins encoded by RAD5, RAD16, and RAD54 may compete for the same substrate after damage induced by UV radiation, possibly at an early step in their respective pathways. 49 refs., 6 figs., 2 tabs

The Polymorphism of DNA Repair Gene ERCC2/XPD Arg156Arg and Susceptibility to Breast Cancer in a Chinese Population

DEFF Research Database (Denmark)

Yin, J. Y.; Liang, D. H.; Vogel, Ulla Birgitte

2009-01-01

Polymorphisms in DNA repair genes are good candidates for modifying cancer risk. ERCC2/XPD, a gene involved in nucleotide excision repair and basal transcription, may influence individual DNA repair capacity, particularly of bulky adducts. This is implicated in cancer susceptibility. To detect...... found between ERCC2/XPD Arg156Arg and risk of breast cancer (AA/AC versus CC: OR = 0.79, 95% CI = 0.49-1.28, P = 0.33; AA versus CC: OR = 0.89, 95% CI = 0.49-1.63, P = 0.72; AC versus CC: OR = 0.74, 95% CI = 0.44-1.24, P = 0.25). Breast cancer cases with the variant AA genotype were marginally younger...

Human longevity and variation in DNA damage response and repair

DEFF Research Database (Denmark)

Debrabant, Birgit; Soerensen, 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...... in genotyping procedures and investigated SNPs, potentially inducing differences in the coverage of gene regions. Specifically, five genes were not covered at all in the German data. Therefore, investigations in additional study populations are needed before final conclusion can be drawn....

DNA Glycosylases Involved in Base Excision Repair May Be Associated with Cancer Risk in BRCA1 and BRCA2 Mutation Carriers

DEFF Research Database (Denmark)

Osorio, Ana; Milne, Roger L; Kuchenbaecker, Karoline

2014-01-01

Single Nucleotide Polymorphisms (SNPs) in genes involved in the DNA Base Excision Repair (BER) pathway could be associated with cancer risk in carriers of mutations in the high-penetrance susceptibility genes BRCA1 and BRCA2, given the relation of synthetic lethality that exists between one of th...

Multiple and variable NHEJ-like genes are involved in resistance to DNA damage in Streptomyces ambofaciens

Directory of Open Access Journals (Sweden)

Grégory Hoff

2016-11-01

Full Text Available Non homologous end-joining (NHEJ is a double strand break (DSB repair pathway which does not require any homologous template and can ligate two DNA ends together. The basic bacterial NHEJ machinery involves two partners: the Ku protein, a DNA end binding protein for DSB recognition and the multifunctional LigD protein composed a ligase, a nuclease and a polymerase domain, for end processing and ligation of the broken ends. In silico analyses performed in the 38 sequenced genomes of Streptomyces species revealed the existence of a large panel of NHEJ-like genes. Indeed, ku genes or ligD domain homologues are scattered throughout the genome in multiple copies and can be distinguished in two categories: the core NHEJ gene set constituted of conserved loci and the variable NHEJ gene set constituted of NHEJ-like genes present in only a part of the species. In Streptomyces ambofaciens ATCC 23877, not only the deletion of core genes but also that of variable genes led to an increased sensitivity to DNA damage induced by electron beam irradiation. Multiple mutants of ku, ligase or polymerase encoding genes showed an aggravated phenotype compared to single mutants. Biochemical assays revealed the ability of Ku-like proteins to protect and to stimulate ligation of DNA ends. RT-qPCR and GFP fusion experiments suggested that ku-like genes show a growth phase dependent expression profile consistent with their involvement in DNA repair during spores formation and/or germination.

Double silencing of relevant genes suggests the existence of the direct link between DNA replication/repair and central carbon metabolism in human fibroblasts.

Science.gov (United States)

Wieczorek, Aneta; Fornalewicz, Karolina; Mocarski, Łukasz; Łyżeń, Robert; Węgrzyn, Grzegorz

2018-04-15

Genetic evidence for a link between DNA replication and glycolysis has been demonstrated a decade ago in Bacillus subtilis, where temperature-sensitive mutations in genes coding for replication proteins could be suppressed by mutations in genes of glycolytic enzymes. Then, a strong influence of dysfunctions of particular enzymes from the central carbon metabolism (CCM) on DNA replication and repair in Escherichia coli was reported. Therefore, we asked if such a link occurs only in bacteria or it is a more general phenomenon. Here, we demonstrate that effects of silencing (provoked by siRNA) of expression of genes coding for proteins involved in DNA replication and repair (primase, DNA polymerase ι, ligase IV, and topoisomerase IIIβ) on these processes (less efficient entry into the S phase of the cell cycle and decreased level of DNA synthesis) could be suppressed by silencing of specific genes of enzymes from CMM. Silencing of other pairs of replication/repair and CMM genes resulted in enhancement of the negative effects of lower expression levels of replication/repair genes. We suggest that these results may be proposed as a genetic evidence for the link between DNA replication/repair and CMM in human cells, indicating that it is a common biological phenomenon, occurring from bacteria to humans. Copyright © 2018 Elsevier B.V. All rights reserved.

Impact of DNA repair genes polymorphism (XPD and XRCC1) on the risk of breast cancer in Egyptian female patients.

Science.gov (United States)

Hussien, Yousry Mostafa; Gharib, Amal F; Awad, Hanan A; Karam, Rehab A; Elsawy, Wael H

2012-02-01

The genes involved in DNA repair system play a crucial role in the protection against mutations. It has been hypothesized that functional deficiencies in highly conserved DNA repair processes resulting from polymorphic variation may increase genetic susceptibility to breast cancer (BC). The aim of the present study was to evaluate the association of genetic polymorphisms in 2 DNA repair genes, XPD (Asp312Asn) and XRCC1 (A399G), with BC susceptibility. We further investigated the potential combined effect of these DNA repair variants on BC risk. Both XPD (xeroderma pigmentosum group D) and XRCC1 (X-ray repair cross-complementing group 1) polymorphisms were characterized in 100 BC Egyptian females and 100 healthy women who had no history of any malignancy by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) method and PCR with confronting two-pair primers (PCR-CTPP), using DNA from peripheral blood in a case control study. Our results revealed that the frequencies of AA genotype of XPD codon 312 polymorphism were significantly higher in the BC patients than in the normal individuals (P ≤ 0.003), and did not observe any association between the XRCC1 Arg399Gln polymorphism and risk of developing BC. Also, no association between both XPD Asp312Asn and XRCC1 A399G polymorphisms and the clinical characteristics of disease. Finally, the combination of AA(XPD) + AG(XRCC1) were significantly associated with BC risk. Our results suggested that, XPD gene is an important candidate gene for susceptibility to BC. Also, gene-gene interaction between XPD(AA) + XRCC1(AG) polymorphism may be associated with increased risk of BC in Egyptian women.

Molecular cloning and biological characterization of the human excision repair gene ERCC-3

International Nuclear Information System (INIS)

Weeda, G.; van Ham, R.C.; Masurel, R.; Westerveld, A.; Odijk, H.; de Wit, J.; Bootsma, D.; van der Eb, A.J.; Hoeijmakers, J.H.

1990-01-01

In this report we present the cloning, partial characterization, and preliminary studies of the biological activity of a human gene, designated ERCC-3, involved in early steps of the nucleotide excision repair pathway. The gene was cloned after genomic DNA transfection of human (HeLa) chromosomal DNA together with dominant marker pSV3gptH to the UV-sensitive, incision-defective Chinese hamster ovary (CHO) mutant 27-1. This mutant belongs to complementation group 3 of repair-deficient rodent mutants. After selection of UV-resistant primary and secondary 27-1 transformants, human sequences associated with the induced UV resistance were rescued in cosmids from the DNA of a secondary transformant by using a linked dominant marker copy and human repetitive DNA as probes. From coinheritance analysis of the ERCC-3 region in independent transformants, we deduce that the gene has a size of 35 to 45 kilobases, of which one essential segment has so far been refractory to cloning. Conserved unique human sequences hybridizing to a 3.0-kilobase mRNA were used to isolate apparently full-length cDNA clones. Upon transfection to 27-1 cells, the ERCC-3 cDNA, inserted in a mammalian expression vector, induced specific and (virtually) complete correction of the UV sensitivity and unscheduled DNA synthesis of mutants of complementation group 3 with very high efficiency. Mutant 27-1 is, unlike other mutants of complementation group 3, also very sensitive toward small alkylating agents. This unique property of the mutant is not corrected by introduction of the ERCC-3 cDNA, indicating that it may be caused by an independent second mutation in another repair function. By hybridization to DNA of a human x rodent hybrid cell panel, the ERCC-3 gene was assigned to chromosome 2, in agreement with data based on cell fusion

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

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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.

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.

RAD24 (=R1/sup S/) gene product of Saccharomyces cerevisiae participates in two different pathways of DNA repair

International Nuclear Information System (INIS)

Eckardt-Schupp, F.; Siede, W.; Game, J.C.

1987-01-01

The moderately UV- and X-ray-sensitive mutant of Saccharomyces cerevisiae originally designated r 1 /sup s/ complements all rad and mms mutants available. Therefore, the new nomination rad24-1 according to the RAD nomenclature is suggested. RAD24 maps on chromosome V, close to RAD3 (1.3 cM). In order to associate the RAD24 gene with one of the three repair pathways, double mutants of rad24 and various representative genes of each pathway were constructed. The UV and X-ray sensitivities of the double mutants compared to the single mutants indicate that RAD24 is involved in excision repair of UV damage (RAD3 epistasis group), as well as in recombination repair of UV and X-ray damage (RAD52 epistasis group). Properties of the mutant are discussed which hint at the control of late steps in the pathways

Isolation of the functional human excision repair gene ERCC5 by intercosmid recombination

International Nuclear Information System (INIS)

Mudgett, J.S.; MacInnes, M.A.

1990-01-01

The complete human nucleotide exicision repair gene ERCC5 was isolated as a functional gene on overlapping cosmids. ERCC5 corrects the excision repair deficiency of Chinese hamster ovary cell line UV135, of complementation group 5. Cosmids that contained human sequences were obtained from a UV-resistant cell line derived from UV135 cells transformed with human genomic DNA. Individually, none of the cosmids complemented the UV135 repair defect; cosmid groups were formed to represent putative human genomic regions, and specific pairs of cosmids that effectively transformed UV135 cells to UV resistance were identified. Analysis of transformants derived from the active cosmid pairs showed that the functional 32-kbp ERCC5 gene was reconstructed by homologous intercosmid recombination. The cloned human sequences exhibited 100% concordance with the locus designated genetically as ERCC5 located on human chromosome 13q. Cosmid-transformed UV135 host cells repaired cytotoxic damage to levels about 70% of normal and repaired UV-irradiated shuttle vector DNA to levels about 82% of normal

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...

Might there be a link between intron 3 VNTR polymorphism in the XRCC4 DNA repair gene and the etiopathogenesis of rheumatoid arthritis?

Science.gov (United States)

Pehlivan, Sacide; Balci, Sibel Oguzkan; Aydeniz, Ali; Pehlivan, Mustafa; Sever, Tugce; Gursoy, Savas

2015-01-01

DNA repair genes are involved in several diseases such as cancers and autoimmune diseases. Previous studies indicated that a DNA repair system was involved in the development of rheumatoid arthritis (RA). In this study, we aimed to examine whether four polymorphisms in the DNA repair genes (xeroderma pigmentosum complementation group D [XPD], X-ray repair cross-complementing group 1 [XRCC1], and X-ray repair cross-complementing group 4 [XRCC4]) were associated with RA. Sixty-five patients with RA and 70 healthy controls (HCs) were examined for XPD (A-751G), XRCC1 (A399G), and XRCC4 (intron 3 VNTR and G-1394T) polymorphisms. All polymorphisms were genotyped by PCR and/or PCR-RFLP. The association between the polymorphisms and RA was analyzed using the chi-square test and de Finetti program. The intron 3 VNTR polymorphism in the XRCC4 gene showed an association with RA patients. The DI genotype was found lower in RA patients (χ(2)=8.227; p=0.0021), while the II genotype was higher in RA patients (χ(2)=5.285; p=0.010). There were deviations from the Hardy-Weinberg Equilibrium (HWE) in both intron 3 VNTR and G-1394T polymorphisms in the XRCC4 gene and in the polymorphism in the XRCC1 gene, and the observed genotype counts deviated from those expected according to the HWE (p=0.027, 0.004, and 0.002, respectively); however, there was no deviation in the other gene polymorphisms. There is no statistical difference between the RA patients and HCs for XPD (A-751G), XRCC1 (A399G), and XRCC4 (G-1394T) gene polymorphisms (p>0.05). Although XPD (A-751G), XRCC1 (A399G), and XRCC4 (G-1394T) gene polymorphisms have been extensively investigated in different clinical pictures, this is the first study to evaluate the role of these polymorphisms in the genetic etiopathogenesis of RA in Turkish patients. In conclusion, we suggested that the intron 3 VNTR polymorphism in the XRCC4 gene may be associated with the etiopathogenesis of RA as a marker of immune aging.

Genetic variation in DNA repair gene XRCC7 (G6721T) and susceptibility to breast cancer.

Science.gov (United States)

Nasiri, Meysam; Saadat, Iraj; Omidvari, Shahpour; Saadat, Mostafa

2012-08-15

The human XRCC7 is a DNA double-strand break (DSBs) repair gene, involved in non-homologous end joining (NHEJ). It is speculated that DNA DSBs repair have an important role during development of breast cancer. The human XRCC7 is a NHEJ DSBs repair gene. Genetic variation G6721T of XRCC7 (rs7003908) is located in the intron 8 of the gene. This polymorphism may regulate splicing and cause mRNA instability. In the present study, we specifically investigated whether common G6721T genetic variant of XRCC7 was associated with an altered risk of breast cancer. The present study included 362 females with breast cancer. Age frequency-matched controls (362 persons) were randomly selected from the healthy female blood donors, according to the age distribution of the cases. Using RFLP-PCR based method, the polymorphism of XRCC7 was determined. The TG (OR=1.20, 95% CI: 0.83-1.74, P=0.320) and TT (OR=1.01, 95% CI: 0.67-1.53, P=0.933) genotypes had no significant effect on risk of breast cancer, in comparison with the GG genotype. Our present findings indicate that the TT and TG genotypes were not associated with an altered breast cancer risk. Copyright © 2012 Elsevier B.V. All rights reserved.

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

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

Gene repair of an Usher syndrome causing mutation by zinc-finger nuclease mediated homologous recombination.

Science.gov (United States)

Overlack, Nora; Goldmann, Tobias; Wolfrum, Uwe; Nagel-Wolfrum, Kerstin

2012-06-26

Human Usher syndrome (USH) is the most frequent cause of inherited deaf-blindness. It is clinically and genetically heterogeneous, assigned to three clinical types of which the most severe type is USH1. No effective treatment for the ophthalmic component of USH exists. Gene augmentation is an attractive strategy for hereditary retinal diseases. However, several USH genes, like USH1C, are expressed in various isoforms, hampering gene augmentation. As an alternative treatment strategy, we applied the zinc-finger nuclease (ZFN) technology for targeted gene repair of an USH1C, causing mutation by homologous recombination. We designed ZFNs customized for the p.R31X nonsense mutation in Ush1c. We evaluated ZFNs for DNA cleavage capability and analyzed ZFNs biocompatibilities by XTT assays. We demonstrated ZFNs mediated gene repair on genomic level by digestion assays and DNA sequencing, and on protein level by indirect immunofluorescence and Western blot analyses. The specifically designed ZFNs did not show cytotoxic effects in a p.R31X cell line. We demonstrated that ZFN induced cleavage of their target sequence. We showed that simultaneous application of ZFN and rescue DNA induced gene repair of the disease-causing mutation on the genomic level, resulting in recovery of protein expression. In our present study, we analyzed for the first time ZFN-activated gene repair of an USH gene. The data highlight the ability of ZFNs to induce targeted homologous recombination and mediate gene repair in USH. We provide further evidence that the ZFN technology holds great potential to recover disease-causing mutations in inherited retinal disorders.

Homozygous germ-line mutation of the PMS2 mismatch repair gene: a unique case report of constitutional mismatch repair deficiency (CMMRD)

OpenAIRE

Ramchander, N. C.; Ryan, N. A. J.; Crosbie, E. J.; Evans, D. G.

2017-01-01

BackgroundConstitutional mismatch repair deficiency syndrome results from bi-allelic inheritance of mutations affecting the key DNA mismatch repair genes: MLH1, MSH2, MSH6 or PMS2. Individuals with bi-allelic mutations have a dysfunctional mismatch repair system from birth; as a result, constitutional mismatch repair deficiency syndrome is characterised by early onset malignancies. Fewer than 150 cases have been reported in the literature over the past 20 years. This is the first report of th...

Transfer of a repair gene from E. coli as a tool in studies on the action of alkylating mutagens in tobacco

Energy Technology Data Exchange (ETDEWEB)

Veleminsky, J; Briza, J; Angelis, K; Satava, J [Institute of Experimental Botany, Czechoslovakian Academy of Sciences, Prague (Czech Republic); Margison, G [Institute of Experimental Botany, Czechoslovakian Academy of Sciences, Prague (Czech Republic); [Paterson Institute for Cancer Research, CRC, Manchester (United Kingdom)

1990-01-01

Full text: Alkylating agents (AA) belong to the most potent mutagens. Nevertheless, the role of individual DNA lesions in the toxic and mutagenic effects of AA in plants are poorly understood. A new tool to study this topic is the transfer of a gene with a specified repair function for a specific DNA lesion. Differences in the responses to AA can be assumed to be caused by changes in the amount of DNA lesion(s) repaired by the introduced gene. Methyl-nitroso urea (MNU) produces 06-methylG and other DNA lesions methylated at O-sites. Taurine-chloroethyl-nitrosourea (TCNH) causes DNA-DNA crosslinks, the formation of which starts with the chloroethylation of G at 06. Both 06-methylG, 04-methylT, O-methylphosphotriesters produced by MNH and 06-chloroethylG produced by TCNH are known to be repaired with AT coded by E. coli ada gene. Transfer of this gene and its expression in tobacco appeared to increase the resistance of the transformed cell to both AA tested. It seems, therefore, likely that the DNA lesions mentioned above are at least partly involved in the production of toxic effects of AA in tobacco. (author)

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

International Nuclear Information System (INIS)

Binkova, Blanka; Chvatalova, Irena; Lnenickova, Zdena; Milcova, Alena; Tulupova, Elena; Farmer, Peter B.; Sram, Radim J.

2007-01-01

levels (r = 0.368, P < 0.001) and negative association between DNA adduct and vitamin C levels (r = -0.290, P = 0.004) was found. The results of multivariate regression analysis showed smoking, vitamin C, polymorphisms of XPD repair gene in exon 23 and GSTM1 gene as significant predictors for total DNA adduct levels. Exposure to ambient air pollution, smoking, and polymorphisms of XPD repair gene in exon 6 were significant predictors for B[a]P-'like' DNA adduct. To sum up, this study suggests that polymorphisms of DNA repair genes involved in nucleotide excision repair may modify aromatic DNA adduct levels and may be useful biomarkers to identify individuals susceptible to DNA damage resulting from c-PAHs exposure

DNA repair synthesis dependent on the uvrA,B gene products

International Nuclear Information System (INIS)

Moses, R.E.; Moody, E.E.M.

1975-01-01

Ultraviolet irradiation of toluene-treated Escherichia coli causes an inhibition of replicative DNA synthesis. This is followed by the appearance of nonconservative DNA repair synthesis which does not require either the polymerase or 5' → 3' exonucleolytic activities of DNA polymerase I. The repair synthesis may be catalyzed by DNA polymerase III activity but does not require a functional DNA polymerase II. The ultraviolet-induced synthesis requires ATP and is dependent on a functional uvrA and uvrB gene product. However, other uvr gene products are not required for the synthesis. The recB function is also not required

Genetic manipulation in Sulfolobus islandicus and functional analysis of DNA repair genes

DEFF Research Database (Denmark)

Zhang, Changyi; Tian, Bin; Li, Suming

2013-01-01

Recently, a novel gene-deletion method was developed for the crenarchaeal model Sulfolobus islandicus, which is a suitable tool for addressing gene essentiality in depth. Using this technique, we have investigated functions of putative DNA repair genes by constructing deletion mutants and studying...

Effects of Radiation and Dietary Iron on Expression of Genes and Proteins Involved in Drug Metabolism

Science.gov (United States)

Faust, K. M.; Wotring, V. E.

2014-01-01

Liver function, especially the rate of metabolic enzyme activities, determines the concentration of circulating drugs and the duration of their efficacy. Most pharmaceuticals are metabolized by the liver, and clinically-used medication doses are given with normal liver function in mind. A drug overdose can result in the case of a liver that is damaged and removing pharmaceuticals from the circulation at a rate slower than normal. Alternatively, if liver function is elevated and removing drugs from the system more quickly than usual, it would be as if too little drug had been given for effective treatment. Because of the importance of the liver in drug metabolism, we want to understand any effects of spaceflight on the enzymes of the liver. Dietary factors and exposure to radiation are aspects of spaceflight that are potential oxidative stressors and both can be modeled in ground experiments. In this experiment, we examined the effects of high dietary iron and low dose gamma radiation (individually and combined) on the gene expression of enzymes involved in drug metabolism, redox homeostasis, and DNA repair. METHODS All procedures were approved by the JSC Animal Care and Use Committee. Male Sprague-Dawley rats were divided into 4 groups (n=8); control, high Fe diet (650 mg iron/kg), radiation (fractionated 3 Gy exposure from a Cs- 137 source) and combined high Fe diet + radiation exposure. Animals were euthanized 24h after the last treatment of radiation; livers were removed immediately and flash -frozen in liquid nitrogen. Expression of genes thought to be involved in redox homeostasis, drug metabolism and DNA damage repair was measured by RT-qPCR. Where possible, protein expression of the same genes was measured by western blotting. All data are expressed as % change in expression normalized to reference gene expression; comparisons were then made of each treatment group to the sham exposed/ normal diet control group. Data was considered significant at phigh Fe

DNA repair gene polymorphisms and risk of cutaneous melanoma: a systematic review and meta-analysis.

Science.gov (United States)

Mocellin, Simone; Verdi, Daunia; Nitti, Donato

2009-10-01

Polymorphisms of DNA repair-related genes might modulate cancer predisposition. We performed a systematic review and meta-analysis of the available evidence regarding the relationship between these polymorphisms and the risk of developing cutaneous melanoma. Relevant studies were searched using PubMed, Medline, Embase, Cancerlit, Cochrane and ISI Web of Knowledge databases. Data were gathered according to the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. The model-free approach was adopted to perform the meta-analysis of the retrieved data. We identified 20 original reports that describe the relationship between melanoma risk and the single-nucleotide polymorphisms (SNPs) of 16 genes (cases = 4195). For seven SNPs considered in at least two studies, the findings were heterogeneous. Data were suitable for meta-analysis only in the case of the XPD/ERCC2 SNP rs13181 (cases = 2308, controls = 3698) and demonstrated that the variant C allele is associated with increased melanoma risk (odds ratio = 1.12, 95% confidence interval = 1.03-1.21, P = 0.01; population attributable risk = 9.6%). This is the first meta-analysis suggesting that XPD/ERCC2 might represent a low-penetrance melanoma susceptibility gene. Much work is still to be done before definitive conclusions can be drawn on the role of DNA repair alterations in melanomagenesis since for the other genes involved in this highly complex process, the available information is scarce or null.

Control of radiation sensitivity of mammalian cells. Regulation of expression of DNA repair genes

International Nuclear Information System (INIS)

Yoshida, Kayo; Morita, Takashi

2003-01-01

This review describes authors' investigations concerning regulation of expression of DNA repair genes for the purpose of control of radiosensitivity of mammalian cells for cancer radiotherapy. One of their experiments concerns the enhancement of sensitivity to radiation and anti-tumor agents by suppressing the expression of mammalian Rad51 gene which playing a central role in recombination repair against DNA double-strand break, by RNA interference (RNAi). Described are the mode of action of RNAi, mechanism of suppression of Rad51 gene expression by it, enhancing effect in radiosensitivity, stable suppression and enhancement by hairpin RNA and its possible usefulness in cancer therapy. The other concerns the histone H2AX gene, which delivering the repair signal post phosphorylation in chromatin against the double-strand break. Experimental results of suppression of the histone H2AX gene by tet-off system, enhancement of radiosensitivity by the suppression and functional recovery by the gene transfer are described, and the radiosensitivity can be thus artificially controlled by tetracycline in authors' F9 2AX (tet/tet) cells. (N.I.)

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.

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

International Nuclear Information System (INIS)

Dupuy, Aurélie; Sarasin, Alain

2015-01-01

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

Functional characterization of two SOS-regulated genes involved in mitomycin C resistance in Caulobacter crescentus.

Science.gov (United States)

Lopes-Kulishev, Carina O; Alves, Ingrid R; Valencia, Estela Y; Pidhirnyj, María I; Fernández-Silva, Frank S; Rodrigues, Ticiane R; Guzzo, Cristiane R; Galhardo, Rodrigo S

2015-09-01

The SOS response is a universal bacterial regulon involved in the cellular response to DNA damage and other forms of stress. In Caulobacter crescentus, previous work has identified a plethora of genes that are part of the SOS regulon, but the biological roles of several of them remain to be determined. In this study, we report that two genes, hereafter named mmcA and mmcB, are involved in the defense against DNA damage caused by mitomycin C (MMC), but not against lesions induced by other common DNA damaging agents, such as UVC light, methyl methanesulfonate (MMS) and hydrogen peroxide. mmcA is a conserved gene that encodes a member of the glyoxalases/dioxygenases protein family, and acts independently of known DNA repair pathways. On the other hand, epistasis analysis showed that mmcB acts in the same pathway as imuC (dnaE2), and is required specifically for MMC-induced mutagenesis, but not for that induced by UV light, suggesting a role for MmcB in translesion synthesis-dependent repair of MMC damage. We show that the lack of MMC-induced mutability in the mmcB strain is not caused by lack of proper SOS induction of the imuABC operon, involved in translesion synthesis (TLS) in C. crescentus. Based on this data and on structural analysis of a close homolog, we propose that MmcB is an endonuclease which creates substrates for ImuABC-mediated TLS patches. Copyright © 2015 Elsevier B.V. All rights reserved.

Radiosensitivity and genes

Energy Technology Data Exchange (ETDEWEB)

Qiyue, Hu; Mingyue, Lun [Suzhou Medical Coll., JS (China)

1995-07-01

Reported effects of some oncogenes, tumour suppressor genes and DNA repair genes on sensitivity of cells to ionizing radiation are reviewed. The role of oncogenes in cellular response to irradiation is discussed, especially the extensively studied oncogenes such as the ras gene family. For tumour suppressor genes, mainly the p53, which is increasingly implicated as a gene affecting radiosensitivity, is reviewed. It is considered that there is a cell cycle checkpoint determinant which is postulated to be able to arrest the irradiated cells in G{sub 1} phase to allow them to repair damage before they undergo DNA synthesis. So far there are six DNA repair genes which have been cloned in mammalian cells, but only one, XRCC1, appears to be involved in repair of human X-ray damage. XRCC1 can correct high sisterchromatid exchange levels when transferred into EM{sub 9} cells, but its expression seems to have no correlation with radiosensitivity of human neck and head tumour cells. Radiosensitivity is an intricate issue which may involve many factors. A scheme of cellular reactions after exposure to irradiation is proposed to indicate a possible sequence of events initiated by ionizing radiation.

Radiosensitivity and genes

International Nuclear Information System (INIS)

Hu Qiyue; Lun Mingyue

1995-07-01

Reported effects of some oncogenes, tumour suppressor genes and DNA repair genes on sensitivity of cells to ionizing radiation are reviewed. The role of oncogenes in cellular response to irradiation is discussed, especially the extensively studied oncogenes such as the ras gene family. For tumour suppressor genes, mainly the p53, which is increasingly implicated as a gene affecting radiosensitivity, is reviewed. It is considered that there is a cell cycle checkpoint determinant which is postulated to be able to arrest the irradiated cells in G 1 phase to allow them to repair damage before they undergo DNA synthesis. So far there are six DNA repair genes which have been cloned in mammalian cells, but only one, XRCC1, appears to be involved in repair of human X-ray damage. XRCC1 can correct high sisterchromatid exchange levels when transferred into EM 9 cells, but its expression seems to have no correlation with radiosensitivity of human neck and head tumour cells. Radiosensitivity is an intricate issue which may involve many factors. A scheme of cellular reactions after exposure to irradiation is proposed to indicate a possible sequence of events initiated by ionizing radiation

Involvement of sensory neurons in bone defect repair in rats

International Nuclear Information System (INIS)

Henmi, Akiko; Nakamura, Megumi; Echigo, Seishi; Sasano, Yasuyuki

2011-01-01

We investigated bone repair in sensory-denervated rats, compared with controls, to elucidate the involvement of sensory neurons. Nine-week-old male Wistar rats received subcutaneous injections of capsaicin to denervate sensory neurons. Rats treated with the same amount of vehicle served as controls. A standardized bone defect was created on the parietal bone. We measured the amount of repaired bone with quantitative radiographic analysis and the mRNA expressions of osteocalcin and cathepsin K with real-time polymerase chain reaction (PCR). Quantitative radiographic analysis showed that the standard deviations and coefficients of variation for the amount of repaired bone were much higher in the capsaicin-treated group than in the control group at any time point, which means that larger individual differences in the amount of repaired bone were found in capsaicin-treated rats than controls. Furthermore, radiographs showed radiolucency in pre-existing bone surrounding the standardized defect only in the capsaicin-treated group, and histological observation demonstrated some multinuclear cells corresponding to the radiolucent area. Real-time PCR indicated that there was no significant difference in the mRNA expression levels of osteocalcin and cathepsin K between the control group and the capsaicin-treated group. These results suggest that capsaicin-induced sensory denervation affects the bone defect repair. (author)

Enrichment of G2/M cell cycle phase in human pluripotent stem cells enhances HDR-mediated gene repair with customizable endonucleases.

Science.gov (United States)

Yang, Diane; Scavuzzo, Marissa A; Chmielowiec, Jolanta; Sharp, Robert; Bajic, Aleksandar; Borowiak, Malgorzata

2016-02-18

Efficient gene editing is essential to fully utilize human pluripotent stem cells (hPSCs) in regenerative medicine. Custom endonuclease-based gene targeting involves two mechanisms of DNA repair: homology directed repair (HDR) and non-homologous end joining (NHEJ). HDR is the preferred mechanism for common applications such knock-in, knock-out or precise mutagenesis, but remains inefficient in hPSCs. Here, we demonstrate that synchronizing synchronizing hPSCs in G2/M with ABT phase increases on-target gene editing, defined as correct targeting cassette integration, 3 to 6 fold. We observed improved efficiency using ZFNs, TALENs, two CRISPR/Cas9, and CRISPR/Cas9 nickase to target five genes in three hPSC lines: three human embryonic stem cell lines, neural progenitors and diabetic iPSCs. neural progenitors and diabetic iPSCs. Reversible synchronization has no effect on pluripotency or differentiation. The increase in on-target gene editing is locus-independent and specific to the cell cycle phase as G2/M phase enriched cells show a 6-fold increase in targeting efficiency compared to cells in G1 phase. Concurrently inhibiting NHEJ with SCR7 does not increase HDR or improve gene targeting efficiency further, indicating that HR is the major DNA repair mechanism after G2/M phase arrest. The approach outlined here makes gene editing in hPSCs a more viable tool for disease modeling, regenerative medicine and cell-based therapies.

Differential gene expression in a DNA double-strand-break repair mutant XRS-5 defective in Ku80. Analysis by cDNA microarray

International Nuclear Information System (INIS)

Chan, John Y.H.; Chen, Lung-Kun; Chang, Jui-Feng

2001-01-01

The ability of cells to rejoin DNA double-strand breaks (DSBs) usually correlates with their radiosensitivity. This correlation has been demonstrated in radiosensitive cells, including the Chinese hamster ovary mutant XRS-5. XRS-5 is defective in a DNA end-binding protein, Ku80, which is a component of a DNA-dependent protein kinase complex used for joining strand breaks. However, Ku80-deficient cells are known to be retarded in cell proliferation and growth as well as other yet to be identified defects. Using custom-made 600-gene cDNA microarray filters, we found differential gene expressions between the wild-type and XRS-5 cells. Defective Ku80 apparently affects the expression of several repair genes, including topoisomerase-I and -IIA, ERCC5, MLH1, and ATM. In contrast, other DNA repair-associated genes, such as GADD45A, EGR1 MDM2 and p53, were not affected. In addition, for large numbers of growth-associated genes, such as cyclins and clks, the growth factors and cytokines were also affected. Down-regulated expression was also found in several categories of seemingly unrelated genes, including apoptosis, angiogenesis, kinase and signaling, phosphatase, stress protein, proto-oncogenes and tumor suppressors, transcription and translation factors. A RT-PCR analysis confirmed that the XRS-5 cells used were defective in Ku80 expression. The diversified groups of genes being affected could mean that Ku80, a multi-functional DNA-binding protein, not only affects DNA repair, but is also involved in transcription regulation. Our data, taken together, indicate that there are specific genes being modulated in Ku80- deficient cells, and that some of the DNA repair pathways and other biological functions are apparently linked, suggesting that a defect in one gene could have global effects on many other processes. (author)

Differential gene expression in a DNA double-strand-break repair mutant XRS-5 defective in Ku80. Analysis by cDNA microarray

Energy Technology Data Exchange (ETDEWEB)

Chan, John Y.H.; Chen, Lung-Kun; Chang, Jui-Feng [National Yang Ming Univ., Taipei, Taiwan (China). Inst. of Radiological Sciences] (and others)

2001-12-01

The ability of cells to rejoin DNA double-strand breaks (DSBs) usually correlates with their radiosensitivity. This correlation has been demonstrated in radiosensitive cells, including the Chinese hamster ovary mutant XRS-5. XRS-5 is defective in a DNA end-binding protein, Ku80, which is a component of a DNA-dependent protein kinase complex used for joining strand breaks. However, Ku80-deficient cells are known to be retarded in cell proliferation and growth as well as other yet to be identified defects. Using custom-made 600-gene cDNA microarray filters, we found differential gene expressions between the wild-type and XRS-5 cells. Defective Ku80 apparently affects the expression of several repair genes, including topoisomerase-I and -IIA, ERCC5, MLH1, and ATM. In contrast, other DNA repair-associated genes, such as GADD45A, EGR1 MDM2 and p53, were not affected. In addition, for large numbers of growth-associated genes, such as cyclins and clks, the growth factors and cytokines were also affected. Down-regulated expression was also found in several categories of seemingly unrelated genes, including apoptosis, angiogenesis, kinase and signaling, phosphatase, stress protein, proto-oncogenes and tumor suppressors, transcription and translation factors. A RT-PCR analysis confirmed that the XRS-5 cells used were defective in Ku80 expression. The diversified groups of genes being affected could mean that Ku80, a multi-functional DNA-binding protein, not only affects DNA repair, but is also involved in transcription regulation. Our data, taken together, indicate that there are specific genes being modulated in Ku80- deficient cells, and that some of the DNA repair pathways and other biological functions are apparently linked, suggesting that a defect in one gene could have global effects on many other processes. (author)

Stress and DNA repair biology of the Fanconi anemia pathway

Science.gov (United States)

Longerich, Simonne; Li, Jian; Xiong, Yong; Sung, Patrick

2014-01-01

Fanconi anemia (FA) represents a paradigm of rare genetic diseases, where the quest for cause and cure has led to seminal discoveries in cancer biology. Although a total of 16 FA genes have been identified thus far, the biochemical function of many of the FA proteins remains to be elucidated. FA is rare, yet the fact that 5 FA genes are in fact familial breast cancer genes and FA gene mutations are found frequently in sporadic cancers suggest wider applicability in hematopoiesis and oncology. Establishing the interaction network involving the FA proteins and their associated partners has revealed an intersection of FA with several DNA repair pathways, including homologous recombination, DNA mismatch repair, nucleotide excision repair, and translesion DNA synthesis. Importantly, recent studies have shown a major involvement of the FA pathway in the tolerance of reactive aldehydes. Moreover, despite improved outcomes in stem cell transplantation in the treatment of FA, many challenges remain in patient care. PMID:25237197

The Seed Repair Response during Germination: Disclosing Correlations between DNA Repair, Antioxidant Response, and Chromatin Remodeling in Medicago truncatula

Directory of Open Access Journals (Sweden)

Andrea Pagano

2017-11-01

Full Text Available This work provides novel insights into the effects caused by the histone deacetylase inhibitor trichostatin A (TSA during Medicago truncatula seed germination, with emphasis on the seed repair response. Seeds treated with H2O and TSA (10 and 20 μM were collected during imbibition (8 h and at the radicle protrusion phase. Biometric data showed delayed germination and impaired seedling growth in TSA-treated samples. Comet assay, performed on radicles at the protrusion phase and 4-days old M. truncatula seedlings, revealed accumulation of DNA strand breaks upon exposure to TSA. Activation of DNA repair toward TSA-mediated genotoxic damage was evidenced by the up-regulation of MtOGG1(8-OXOGUANINE GLYCOSYLASE/LYASE gene involved in the removal of oxidative DNA lesions, MtLIGIV(LIGASE IV gene, a key determinant of seed quality, required for the rejoining of DNA double strand breaks and TDP(TYROSYL-DNA PHOSPHODIESTERASE genes encoding the multipurpose DNA repair enzymes tyrosyl-DNA phosphodiesterases. Since radical scavenging can prevent DNA damage, the specific antioxidant activity (SAA was measured by DPPH (1,1-diphenyl-2-picrylhydrazyl and Folin-Ciocalteu reagent assays. Fluctuations of SAA were observed in TSA-treated seeds/seedlings concomitant with the up-regulation of antioxidant genes MtSOD(SUPEROXIDE DISMUTASE, MtAPX(ASCORBATE PEROXIDASE and MtMT2(TYPE 2 METALLOTHIONEIN. Chromatin remodeling, required to facilitate the access of DNA repair enzymes at the damaged sites, is also part of the multifaceted seed repair response. To address this aspect, still poorly explored in plants, the MtTRRAP(TRANSFORMATION/TRANSACTIVATION DOMAIN-ASSOCIATED PROTEIN gene was analyzed. TRRAP is a transcriptional adaptor, so far characterized only in human cells where it is needed for the recruitment of histone acetyltransferase complexes to chromatin during DNA repair. The MtTRRAP gene and the predicted interacting partners MtHAM2 (HISTONE ACETYLTRANSFERASE OF

Energy and Technology Review: Unlocking the mysteries of DNA repair

Energy Technology Data Exchange (ETDEWEB)

Quirk, W.A.

1993-04-01

DNA, the genetic blueprint, has the remarkable property of encoding its own repair following diverse types of structural damage induced by external agents or normal metabolism. We are studying the interplay of DNA damaging agents, repair genes, and their protein products to decipher the complex biochemical pathways that mediate such repair. Our research focuses on repair processes that correct DNA damage produced by chemical mutagens and radiation, both ionizing and ultraviolet. The most important type of DNA repair in human cells is called excision repair. This multistep process removes damaged or inappropriate pieces of DNA -- often as a string of 29 nucleotides containing the damage -- and replaces them with intact ones. We have isolated, cloned, and mapped several human repair genes associated with the nucleotide excision repair pathway and involved in the repair of DNA damage after exposure to ultraviolet light or mutagens in cooked food. We have shown that a defect in one of these repair genes, ERCC2, is responsible for the repair deficiency in one of the groups of patients with the recessive genetic disorder xeroderma pigmentosum (XP group D). We are exploring ways to purify sufficient quantities (milligrams) of the protein products of these and other repair genes so that we can understand their functions. Our long-term goals are to link defective repair proteins to human DNA repair disorders that predispose to cancer, and to produce DNA-repair-deficient mice that can serve as models for the human disorders.

Role of DNA repair in repair of cytogenetic damages. Slowly repaired DNA injuries involved in cytogenetic damages repair

International Nuclear Information System (INIS)

Zaichkina, S.I.; Rozanova, O.M.; Aptikaev, G.F.; Ganassi, E.Eh.

1989-01-01

Caffeine was used to study the kinetics of cytogenetic damages repair in Chinese hamster fibroblasts. Its half-time (90 min) was shown to correlate with that of repair of slowly repaired DNA damages. The caffeine-induced increase in the number of irreparable DNA damages, attributed to inhibition of double-strand break repair, is in a quantitative correlation with the effect of the cytogenetic damage modification

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

Directory of Open Access Journals (Sweden)

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.

Isolated Subscapularis Repair in Irreparable Posterosuperior Massive Rotator Cuff Tears Involving the Subscapularis Tendon.

Science.gov (United States)

Kim, Sung-Jae; Choi, Yun-Rak; Jung, Min; Lee, Won-Yong; Chun, Yong-Min

2017-05-01

No previous study has examined whether isolated subscapularis tendon repair in irreparable posterosuperior massive rotator tears involving the subscapularis tendon in relatively young patients without arthritis can yield satisfactory outcomes. We hypothesized that this procedure would produce favorable outcomes in patients who might otherwise be candidates for reverse arthroplasty. Case series; Level of evidence, 4. This retrospective study included 24 patients in their 50s and 60s, without shoulder arthritis, who underwent arthroscopic isolated subscapularis repair for an irreparable massive rotator cuff tear involving the subscapularis tendon. Preoperative and postoperative visual analog scale (VAS) pain scores, subjective shoulder values (SSVs), University of California at Los Angeles (UCLA) shoulder scores, American Shoulder and Elbow Surgeons (ASES) scores, subscapularis strength (modified bell-press test; maximum of 5), and shoulder active range of motion (ROM) were assessed. Postoperative magnetic resonance arthrography (MRA) was performed 6 months postoperatively to assess structural integrity of the repaired subscapularis. At a mean 34.8 months (range, 24-49 months) of follow-up, VAS pain scores (improved from 7.1 to 2.5), SSVs (33.3 to 75.2), ASES scores (35.9 to 76.0), UCLA shoulder scores (11.6 to 24.8), subscapularis strength, and ROM were significantly improved compared with preoperative measurements ( P rotation improved significantly ( P rotation exhibited no significant improvement. Follow-up MRA was performed in 22 patients (92%) and showed retear of the repaired subscapularis in 6 (27% of the 22). Isolated repair of the subscapularis tendon in irreparable massive rotator cuff tears involving the subscapularis tendon yielded satisfactory short-term outcomes and structural integrity in patients in their 50s and 60s without arthritis. If patients with irreparable massive rotator cuff tears involving the subscapularis tendon are relatively young or

Cloning of a postreplication repair gene in Drosophila

International Nuclear Information System (INIS)

Banga, S.S.; Yamamoto, A.H.; Mason, J.M.; Boyd, J.B.

1987-01-01

Mutants at the mei-41 locus in Drosophila are strongly hypersensitive to each of eight tested mutagens. Mutant flies exhibit reduced meiotic recombination and elevated levels of chromosomal aberrations. In analogy with the defect in xeroderma pigmentosum variant cells, mei-41 cells are strongly defective in postreplication repair following UV radiation. In preparation for cloning that gene they have performed complementation studies between chromosomal aberrations and mei-41 mutants. That study has localized the mei-41 gene to polytene chromosome bands 14C4-6. A chromosomal walk conducted in that region has recovered about 65 kb of contiguous DNA sequence. The position of the mei-41 gene within that region has been established with the aid of a mutation in that gene which was generated by the insertion of a transposable element. Transcription mapping is being employed to define the complete coding region of the gene in preparation for investigations of gene function

Involvement of recQ in the ultraviolet damage repair pathway in Deinococcus radiodurans

International Nuclear Information System (INIS)

Hua Xiaoting; Huang Lifen; Tian Bing; Hua Yuejin

2008-01-01

Deinococcus radiodurans is a bacterium which can survive extremely DNA damage. To investigate the relationship between recQ and the ultraviolet radiation (UV) damage repair pathway, we created a four mutant strain by constructing recQ knockout mutants in uvrA1, uvrA2, and uvsE backgrounds. Using the rpoB/Rif r system, we measured the mutation frequencies and rates in wild type, recQ (MQ), uvsE uvrA1 uvrA2 (TNK006), and uvsE uvrA1 uvrA2 recQ (TQ). We then isolated Rif r mutants of these strains and sequenced the rpoB gene. The mutation frequency of TQ was 6.4, 10.1, and 2.43 times that of wild type, MQ, and TNK006, respectively, and resulted in rates of 4.7, 6.71, and 2.15 folds higher than that of wild type, MQ, and TNK006, respectively. All the strains demonstrated specific mutational hotspots. Furthermore, the TQ strain showed a transversion bias that was different from the other three strains. The results indicate that recQ is involved in the ultraviolet damage repair pathway via the interaction between recQ and uvrA1, uvrA2, and uvsE in D. radiodurans

Effect of specific enzyme inhibitors on replication, total genome DNA repair and on gene-specific DNA repair after UV irradiation in CHO cells

Energy Technology Data Exchange (ETDEWEB)

Jones, J.C.; Stevsner, Tinna; Bohr, Vilhelm A. (National Cancer Institute, NIH, Bethesda, MD (USA). Division of Cancer Treatment, Laboratory of Molecular Pharmacology); Mattern, M.R. (Smith Kline Beecham Pharmaceuticals, King of Prussia, PA (USA). Department of Biomolecular Discovery)

1991-09-01

The effects were studied of some specific enzyme inhibitors on DNA repair and replication after UV damage in Chinese hamster ovary cells. The DNA repair was studied at the level of the average, overall genome and also in the active dihydrofolate reductase gene. Replication was measured in the overall genome. The inhibitors were tested of DNA poly-merase {alpha} and {delta} (aphidicolin), of poly(ADPr) polymerase (3-aminobenzamide), of ribonucleotide reductase (hydroxyurea), of topo-isomerase I (camptothecin), and of topoisomerase II (merbarone, VP-16). In addition, the effects were tested of the potential topoisomerase I activator, {beta}-lapachone. All of these compounds inhibited genome replication and all topoisomerase inhibitors affected the overall genome repair; {beta}-lapachone stimulated it. None of these compounds had any effect on the gene-specific repair. (author). 36 refs.; 3 figs.; 2 tabs.

Comprehensive Pathway-Based Association Study of DNA Repair Gene Variants and the Risk of Nasopharyngeal Carcinoma

Science.gov (United States)

Qin, Hai-De; Shugart, Yin Yao; Bei, Jin-Xin; Pan, Qing-Hua; Chen, Lina; Feng, Qi-Sheng; Chen, Li-Zhen; Huang, Wei; Liu, Jian Jun; Jorgensen, Timothy J.; Zeng, Yi-Xin; Jia, Wei-Hua

2011-01-01

DNA repair plays a central role in protecting against environmental carcinogenesis, and genetic variants of DNA repair genes have been reported to be associated with several human malignancies. To assess whether DNA gene variants were associated with nasopharyngeal carcinoma (NPC) risk, a candidate gene association study was conducted among the Cantonese population within the Guangdong Province, China --the ethnic group with the highest risk for NPC. A two-stage study design was utilized. In the discovery stage, 676 tagging SNPs covering 88 DNA repair genes were genotyped in a matched case-control study (cases/controls = 755/755). Eleven SNPs with Ptrend Cantonese population (cases/controls = 1,568/1,297). Two of the SNPs (rs927220 and rs11158728) – both in RAD51L1 – remained strongly associated with NPC. The SNP rs927220 had a significant Pcombined of 5.55 × 10−5, with OR = 1.20 (95%CI = 1.10 to 1.30), Bonferroni corrected P = 0.0381. The other SNP (rs11158728), which is in strong LD with rs927220 (r2 = 0.7), had a significant Pcombined of 2.0 × 10−4, Bonferroni corrected P = 0.1372. Gene-environment interaction analysis suggested that the exposures of salted-fish consumption and cigarette smoking had potential interactions with DNA repair gene variations, but need to be further investigated. Our findings support the notion that DNA repair genes, in particular RAD51L1, play a role in NPC etiology and development. PMID:21368091

The phytochemical 3,3'-diindolylmethane decreases expression of AR-controlled DNA damage repair genes through repressive chromatin modifications and is associated with DNA damage in prostate cancer cells.

Science.gov (United States)

Palomera-Sanchez, Zoraya; Watson, Gregory W; Wong, Carmen P; Beaver, Laura M; Williams, David E; Dashwood, Roderick H; Ho, Emily

2017-09-01

Androgen receptor (AR) is a transcription factor involved in normal prostate physiology and prostate cancer (PCa) development. 3,3'-Diindolylmethane (DIM) is a promising phytochemical agent against PCa that affects AR activity and epigenetic regulators in PCa cells. However, whether DIM suppresses PCa via epigenetic regulation of AR target genes is unknown. We assessed epigenetic regulation of AR target genes in LNCaP PCa cells and showed that DIM treatment led to epigenetic suppression of AR target genes involved in DNA repair (PARP1, MRE11, DNA-PK). Decreased expression of these genes was accompanied by an increase in repressive chromatin marks, loss of AR occupancy and EZH2 recruitment to their regulatory regions. Decreased DNA repair gene expression was associated with an increase in DNA damage (γH2Ax) and up-regulation of genomic repeat elements LINE1 and α-satellite. Our results suggest that DIM suppresses AR-dependent gene transcription through epigenetic modulation, leading to DNA damage and genome instability in PCa cells. Published by Elsevier Inc.

Mediator links transcription and DNA repair by facilitating Rad2/XPG recruitment.

Science.gov (United States)

Eyboulet, Fanny; Cibot, Camille; Eychenne, Thomas; Neil, Helen; Alibert, Olivier; Werner, Michel; Soutourina, Julie

2013-12-01

Mediator is a large multiprotein complex conserved in all eukaryotes. The crucial function of Mediator in transcription is now largely established. However, we found that this complex also plays an important role by connecting transcription with DNA repair. We identified a functional contact between the Med17 Mediator subunit and Rad2/XPG, the 3' endonuclease involved in nucleotide excision DNA repair. Genome-wide location analyses revealed that Rad2 is associated with RNA polymerase II (Pol II)- and Pol III-transcribed genes and telomeric regions in the absence of exogenous genotoxic stress. Rad2 occupancy of Pol II-transcribed genes is transcription-dependent. Genome-wide Rad2 occupancy of class II gene promoters is well correlated with that of Mediator. Furthermore, UV sensitivity of med17 mutants is correlated with reduced Rad2 occupancy of class II genes and concomitant decrease of Mediator interaction with Rad2 protein. Our results suggest that Mediator is involved in DNA repair by facilitating Rad2 recruitment to transcribed genes.

Mechanisms involved in repairing the lesions induced in pBR 322 by PUVA treatment (8-Methoxypsoralen + ultraviolet A light)

International Nuclear Information System (INIS)

Bauluz, C.

1988-01-01

This work deals with the genotoxic effects derived from damaging pBR322 DNA through PUVA treatment (8-Methoxypsoralen plusUVA light), both with respect to the lethality and mutagenicity of the lesions produced by the treatment. The mechanisms involved in the repair of the plasmid lesions have been investigated by transforming several strains of E. coli differing in their DNA-repair capacities. The frequency, distribution and type of mutations occurring in a restriction fragment of the damaged plasmid were determined in order to establish the mutagenic features of the PUVA treatment. Damages produced bY PUVA habe a strong lethal effect on plasmid survival; however, partial recovery is possible through some of the bacterial DNA repair pathways, namely Excision repair, SOS-repair and a third mechanism which appears to be independent from the analised genes and is detected at high density of lesions per plasmid molecule. PUVA treatment produces a high increase in plasmid mutagenesis; however, the contribution of such an increase to the whole plasmid survival is negligible. Only punctual mutations were detected and consisted mainly in base-pair substitutions. Some mutation-prone regions were sound inside the investigated DNA fragment, a though their existence is more likely to be related with the structure acquired by the damaged DNA than with the type of damaging agent. (Author)

The mRNA expression of XRCC repair genes in mice after γ-ray radiation

International Nuclear Information System (INIS)

Wang Qin; Yue Jingyin; Li Jin; Mu Chuanjie; Fan Feiyue

2006-01-01

Objective: To investigate the role of XRCC repair genes in radioresistance of IRM-2 inbred mice. Methods: Northern hybridization was used to measure mRNA expression of XRCC1 and XRCC5 genes in IRM-2 inbred mice. ICR/JCL and 615 after exposure to different doses of γ-ray radiation at different postirradiation time. Results: The levels of XRCC1 and XRCC5 mRNA expression in control IRM-2 mice were higher significantly than those in their control parental mice (P<0.01 and P<0.05). The mRNA expression of XRCC genes in ICR/JCL and 615 mice all increased to some extent after exposure 1, 2 and 4 Gy radiation. But the levels were significantly higher at 2h postirradiation (P<0.05) . The levels of XRCC mRNA expression in IRM-2 mice did not increase significnatly compared with the control mice after exposure 1 and 2 Gy radiation. But the levels of XRCC1 and XRCC5 mRNA expression increased markedly at 4Gy 1h postirradiation (P<0.05 and P<0.01). Conclusion: The basal levels of XRCC1 and XRCC5 mRNA expression in IRM-2 mice were high. The high level of XRCC5 mRNA expression was involved in the repair of DNA double strand breaks induced by higher dose radiation, which perhaps was one of radioresistance causes of IRM-2 mice. (authors)

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.

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

.003). A significant difference in both the total (P < 0.05) and the B[a]P-'like' DNA adducts (P < 0.01) between smokers and nonsmokers within both groups was observed. A significant positive association between DNA adduct and cotinine levels (r = 0.368, P < 0.001) and negative association between DNA adduct and vitamin C levels (r = -0.290, P = 0.004) was found. The results of multivariate regression analysis showed smoking, vitamin C, polymorphisms of XPD repair gene in exon 23 and GSTM1 gene as significant predictors for total DNA adduct levels. Exposure to ambient air pollution, smoking, and polymorphisms of XPD repair gene in exon 6 were significant predictors for B[a]P-'like' DNA adduct. To sum up, this study suggests that polymorphisms of DNA repair genes involved in nucleotide excision repair may modify aromatic DNA adduct levels and may be useful biomarkers to identify individuals susceptible to DNA damage resulting from c-PAHs exposure.

Differentiation and injury-repair signals modulate the interaction of E2F and pRB proteins with novel target genes in keratinocytes.

Science.gov (United States)

Chang, Wing Y; Andrews, Joseph; Carter, David E; Dagnino, Lina

2006-08-01

E2F transcription factors are central to epidermal morphogenesis and regeneration after injury. The precise nature of E2F target genes involved in epidermal formation and repair has yet to be determined. Identification of these genes is essential to understand how E2F proteins regulate fundamental aspects of epidermal homeostasis and transformation. We have conducted a genome-wide screen using CpG island microarray analysis to identify novel promoters bound by E2F3 and E2F5 in human keratinocytes. We further characterized several of these genes, and determined that multiple E2F and retinoblastoma (pRb) family proteins associate with them in exponentially proliferating cells. We also assessed the effect on E2F and pRb binding to those genes in response to differentiation induced by bone morphogenetic protein-6 (BMP-6), or to activation of repair mechanisms induced by transforming growth factor-beta (TGF-beta). These studies demonstrate promoter- and cytokine-specific changes in binding profiles of E2F and/or pRb family proteins. For example, E2F1, 3, 4 and p107 were recruited to the N-myc promoter in cells treated with BMP-6, whereas E2F1, 3, 4, 5, p107 and p130 were bound to this promoter in the presence of TGF-beta. Functionally, these different interactions resulted in transcriptional repression by BMP-6 and TGF-beta of the N-myc gene, via mechanisms that involved E2F binding to the promoter and association with pRb-family proteins. Thus, multiple combinations of E2F and pRb family proteins may associate with and transcriptionally regulate a given target promoter in response to differentiation and injury-repair stimuli in epidermal keratinocytes.

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

International Nuclear Information System (INIS)

Leadon, S.A.; Copper, P.K.

1993-01-01

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

Phylogeny of Mycobacterium tuberculosis Beijing strains constructed from polymorphisms in genes involved in DNA replication, recombination and repair.

Science.gov (United States)

Mestre, Olga; Luo, Tao; Dos Vultos, Tiago; Kremer, Kristin; Murray, Alan; Namouchi, Amine; Jackson, Céline; Rauzier, Jean; Bifani, Pablo; Warren, Rob; Rasolofo, Voahangy; Mei, Jian; Gao, Qian; Gicquel, Brigitte

2011-01-20

The Beijing family is a successful group of M. tuberculosis strains, often associated with drug resistance and widely distributed throughout the world. Polymorphic genetic markers have been used to type particular M. tuberculosis strains. We recently identified a group of polymorphic DNA repair replication and recombination (3R) genes. It was shown that evolution of M. tuberculosis complex strains can be studied using 3R SNPs and a high-resolution tool for strain discrimination was developed. Here we investigated the genetic diversity and propose a phylogeny for Beijing strains by analyzing polymorphisms in 3R genes. A group of 3R genes was sequenced in a collection of Beijing strains from different geographic origins. Sequence analysis and comparison with the ones of non-Beijing strains identified several SNPs. These SNPs were used to type a larger collection of Beijing strains and allowed identification of 26 different sequence types for which a phylogeny was constructed. Phylogenetic relationships established by sequence types were in agreement with evolutionary pathways suggested by other genetic markers, such as Large Sequence Polymorphisms (LSPs). A recent Beijing genotype (Bmyc10), which included 60% of strains from distinct parts of the world, appeared to be predominant. We found SNPs in 3R genes associated with the Beijing family, which enabled discrimination of different groups and the proposal of a phylogeny. The Beijing family can be divided into different groups characterized by particular genetic polymorphisms that may reflect pathogenic features. These SNPs are new, potential genetic markers that may contribute to better understand the success of the Beijing family.

Phylogeny of Mycobacterium tuberculosis Beijing strains constructed from polymorphisms in genes involved in DNA replication, recombination and repair.

Directory of Open Access Journals (Sweden)

Olga Mestre

2011-01-01

Full Text Available The Beijing family is a successful group of M. tuberculosis strains, often associated with drug resistance and widely distributed throughout the world. Polymorphic genetic markers have been used to type particular M. tuberculosis strains. We recently identified a group of polymorphic DNA repair replication and recombination (3R genes. It was shown that evolution of M. tuberculosis complex strains can be studied using 3R SNPs and a high-resolution tool for strain discrimination was developed. Here we investigated the genetic diversity and propose a phylogeny for Beijing strains by analyzing polymorphisms in 3R genes.A group of 3R genes was sequenced in a collection of Beijing strains from different geographic origins. Sequence analysis and comparison with the ones of non-Beijing strains identified several SNPs. These SNPs were used to type a larger collection of Beijing strains and allowed identification of 26 different sequence types for which a phylogeny was constructed. Phylogenetic relationships established by sequence types were in agreement with evolutionary pathways suggested by other genetic markers, such as Large Sequence Polymorphisms (LSPs. A recent Beijing genotype (Bmyc10, which included 60% of strains from distinct parts of the world, appeared to be predominant.We found SNPs in 3R genes associated with the Beijing family, which enabled discrimination of different groups and the proposal of a phylogeny. The Beijing family can be divided into different groups characterized by particular genetic polymorphisms that may reflect pathogenic features. These SNPs are new, potential genetic markers that may contribute to better understand the success of the Beijing family.

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

International Nuclear Information System (INIS)

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

2015-01-01

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

Enhancement of ultraviolet-DNA repair in denV gene transfectants and T4 endonuclease V-liposome recipients

International Nuclear Information System (INIS)

Kibitel, J.T.; Yee, V.; Yarosh, D.B.

1991-01-01

The phage T4 denV gene, coding for the pyrimidine-dimer specific T4 endonuclease V, was transfected into human repair-proficient fibroblasts, repair-deficient xeroderma pigmentosum fibroblasts, and wild type CHO hamster cells. Transfectants maintained denV DNA and expressed denV mRNA. Purified T4 endonuclease V encapsulated in liposomes was also used to treat repair-proficient and -deficient human cells. The denV transfected clones and liposome-treated cells showed increased unscheduled DNA synthesis and enhanced removal of pyrimidine dimers compared to controls. Both denV gene transfection and endonuclease V liposome treatment enhanced post-UV survival in xeroderma pigmentosum cells but had no effect on survival in repair-proficient human or hamster cells. The results demonstrate that an exogenous DNA repair enzyme can correct the DNA repair defect in xeroderma pigmentosum cells and enhance DNA repair in normal cells. (author)

Role of gene 59 of bacteriophage T4 in repair of uv-irradiated and alkylated DNA in vivo

International Nuclear Information System (INIS)

Wu, R.; Wu, J.L.; Yeh, Y.C.

1975-01-01

Nonsense mutants in gene 59 (amC5, am HL628) were used to study the role of this gene in the repair of uv-damaged and alkylated DNA of bacteriophage T4 in vivo. The higher sensitivity to uv irradiation and alkylation of gene 59 mutants after exposure to these agents was established by a comparison of the survival fractions with wild type. Zonal centrifugal analysis of both parental and nascent mutant intracellular DNA molecules after uv irradiation showed that immediately after exposure the size of single-stranded DNA fragments was the same as the wild-type intracellular DNA. However, the capability of rejoining fragmented intracellular DNA was greatly reduced in the mutant. In contrast, the wild-type-infected cells under the same condition resumed DNA replication and repaired its DNA to normal size. Methyl methanesulfonate induced more randomly fragmented intracellular DNA, when compared to uv irradiation. The rate of rejoining under these conditions as judged from their sedimentation profiles was also greatly reduced in mutant-infected cells. Further evidence is presented that uv repair is not a simple consequence of arrested DNA replication, which is a phenotype of the mutant when infected in a nonpermissive host, Escherichia coli B(su - ), but rather that the DNA repair function of gene 59 is independent of the replication function. These and other data presented indicate that a product(s) of gene 59 is essential for both repair of uv lesions and repair of alkylation damage of DNA in vivo. It is suggested that gene 59 may have two functions during viral development: DNA replication and replication repair of DNA molecules

Involvement of DNA polymerase δ in DNA repair synthesis in human fibroblasts at late times after ultraviolet irradiation

International Nuclear Information System (INIS)

Dresler, S.L.; Gowans, B.J.; Robinson-Hill, R.M.; Hunting, D.J.

1988-01-01

DNA repair synthesis following UV irradiation of confluent human fibroblasts has a biphasic time course with an early phase of rapid nucleotide incorporation and a late phase of much slower nucleotide incorporation. The biphasic nature of this curve suggests that two distinct DNA repair systems may be operative. Previous studies have specifically implicated DNA polymerase δ as the enzyme involved in DNA repair synthesis occurring immediately after UV damage. In this paper, the authors describe studies of DNA polymerase involvement in DNA repair synthesis in confluent human fibroblasts at late times after UV irradiation. Late UV-induced DNA repair synthesis in both intact and permeable cells was found to be inhibited by aphidicolin, indicating the involvement of one of the aphidicolin-sensitive DNA polymerases, α or δ. In permeable cells, the process was further analyzed by using the nucleotide analogue (butylphenyl)-2'-deoxyguanosine 5'-triphosphate, which inhibits DNA polymerase α several hundred times more strongly than it inhibits DNA polymerase δ. The (butylphenyl)-2'-deoxyguanosine 5'-triphosphate inhibition curve for late UV-induced repair synthesis was very similar to that for polymerase δ. It appears that repair synthesis at late time after UV irradiation, like repair synthesis at early times, is mediated by DNA polymerase δ

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

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

Indian Academy of Sciences (India)

Abstract. Genetic polymorphisms in some DNA repair proteins are associated with a number of malignant transformations like head and ... Such studies may benefit from analysis of multiple genes or polymorphisms and from the ... low survival and high morbidity when diagnosed in advanced ...... racial and/or ethnic cohort.

CD133+ cells contribute to radioresistance via altered regulation of DNA repair genes in human lung cancer cells

International Nuclear Information System (INIS)

Desai, Amar; Webb, Bryan; Gerson, Stanton L.

2014-01-01

Background: Radioresistance in human tumors has been linked in part to a subset of cells termed cancer stem cells (CSCs). The prominin 1 (CD133) cell surface protein is proposed to be a marker enriching for CSCs. We explore the importance of DNA repair in contributing to radioresistance in CD133+ lung cancer cells. Materials and methods: A549 and H1299 lung cancer cell lines were used. Sorted CD133+ cells were exposed to either single 4 Gy or 8 Gy doses and clonogenic survival measured. ϒ-H2AX immunofluorescence and quantitative real time PCR was performed on sorted CD133+ cells both in the absence of IR and after two single 4 Gy doses. Lentiviral shRNA was used to silence repair genes. Results: A549 but not H1299 cells expand their CD133+ population after single 4 Gy exposure, and isolated A549 CD133+ cells demonstrate IR resistance. This resistance corresponded with enhanced repair of DNA double strand breaks (DSBs) and upregulated expression of DSB repair genes in A549 cells. Prior IR exposure of two single 4 Gy doses resulted in acquired DNA repair upregulation and improved repair proficiency in both A549 and H1299. Finally Exo1 and Rad51 silencing in A549 cells abrogated the CD133+ IR expansion phenotype and induced IR sensitivity in sorted CD133+ cells. Conclusions: CD133 identifies a population of cells within specific tumor types containing altered expression of DNA repair genes that are inducible upon exposure to chemotherapy. This altered gene expression contributes to enhanced DSB resolution and the radioresistance phenotype of these cells. We also identify DNA repair genes which may serve as promising therapeutic targets to confer radiosensitivity to CSCs

Identification of novel target genes involved in Indian Fanconi anemia patients using microarray.

Science.gov (United States)

Shyamsunder, Pavithra; Ganesh, Kripa S; Vidyasekar, Prasanna; Mohan, Sheila; Verma, Rama Shanker

2013-12-01

Fanconi anemia (FA) is a genetic disorder characterized by progressive bone marrow failure and a predisposition to cancers. Mutations have been documented in 15 FA genes that participate in the FA-BRCA DNA repair pathway, a fundamental pathway in the development of the disease and the presentation of its characteristic symptoms. Certain symptoms such as oxygen sensitivity, hematological abnormalities and impaired immunity suggest that FA proteins could participate in or independently control other pathways as well. In this study, we identified 9 DNA repair genes that were down regulated in a genome wide analysis of 6 Indian Fanconi anemia patients. Functional clustering of a total of 233 dysregulated genes identified key biological processes that included regulation of transcription, DNA repair, cell cycle and chromosomal organization. Microarray data revealed the down regulation of ATXN3, ARID4A and ETS-1, which were validated by RTPCR in a subsequent sample set of 9 Indian FA patients. Here we report for the first time a gene expression profile of Fanconi anemia patients from the Indian population and a pool of genes that might aid in the acquisition and progression of the FA phenotype. © 2013 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

Dupuy, Aurélie; Sarasin, Alain

2015-06-01

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. Copyright © 2014 Elsevier B.V. All rights reserved.

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.

Dietary Berries and Ellagic Acid Prevent Oxidative DNA Damage and Modulate Expression of DNA Repair Genes

Directory of Open Access Journals (Sweden)

Ramesh C. Gupta

2008-03-01

Full Text Available DNA damage is a pre-requisite for the initiation of cancer and agents that reduce this damage are useful in cancer prevention. In this study, we evaluated the ability of whole berries and berry phytochemical, ellagic acid to reduce endogenous oxidative DNA damage. Ellagic acid was selected based on > 95% inhibition of 8-oxodeoxyguosine (8-oxodG and other unidentified oxidative DNA adducts induced by 4-hydroxy-17B;-estradiol and CuCl2 in vitro. Inhibition of the latter occurred at lower concentrations (10 u(microM than that for 8-oxodG (100 u(microM. In the in vivo study, female CD-1 mice (n=6 were fed either a control diet or diet supplemented with ellagic acid (400 ppm and dehydrated berries (5% w/w with varying ellagic acid contents -- blueberry (low, strawberry (medium and red raspberry (high, for 3 weeks. Blueberry and strawberry diets showed moderate reductions in endogenous DNA adducts (25%. However, both red raspberry and ellagic acid diets showed a significant reduction of 59% (p < 0.001 and 48% (p < 0.01, respectively. Both diets also resulted in a 3-8 fold over-expression of genes involved in DNA repair such as xeroderma pigmentosum group A complementing protein (XPA, DNA excision repair protein (ERCC5 and DNA ligase III (DNL3. These results suggest that red raspberry and ellagic acid reduce endogenous oxidative DNA damage by mechanisms which may involve increase in DNA repair.

DNA glycosylases involved in base excision repair may be associated with cancer risk in BRCA1 and BRCA2 mutation carriers.

Directory of Open Access Journals (Sweden)

Ana Osorio

2014-04-01

Full Text Available Single Nucleotide Polymorphisms (SNPs in genes involved in the DNA Base Excision Repair (BER pathway could be associated with cancer risk in carriers of mutations in the high-penetrance susceptibility genes BRCA1 and BRCA2, given the relation of synthetic lethality that exists between one of the components of the BER pathway, PARP1 (poly ADP ribose polymerase, and both BRCA1 and BRCA2. In the present study, we have performed a comprehensive analysis of 18 genes involved in BER using a tagging SNP approach in a large series of BRCA1 and BRCA2 mutation carriers. 144 SNPs were analyzed in a two stage study involving 23,463 carriers from the CIMBA consortium (the Consortium of Investigators of Modifiers of BRCA1 and BRCA2. Eleven SNPs showed evidence of association with breast and/or ovarian cancer at p<0.05 in the combined analysis. Four of the five genes for which strongest evidence of association was observed were DNA glycosylases. The strongest evidence was for rs1466785 in the NEIL2 (endonuclease VIII-like 2 gene (HR: 1.09, 95% CI (1.03-1.16, p = 2.7 × 10(-3 for association with breast cancer risk in BRCA2 mutation carriers, and rs2304277 in the OGG1 (8-guanine DNA glycosylase gene, with ovarian cancer risk in BRCA1 mutation carriers (HR: 1.12 95%CI: 1.03-1.21, p = 4.8 × 10(-3. DNA glycosylases involved in the first steps of the BER pathway may be associated with cancer risk in BRCA1/2 mutation carriers and should be more comprehensively studied.

Recombinational DNA repair and human disease

Energy Technology Data Exchange (ETDEWEB)

Thompson, Larry H.; Schild, David

2002-11-30

We review the genes and proteins related to the homologous recombinational repair (HRR) pathway that are implicated in cancer through either genetic disorders that predispose to cancer through chromosome instability or the occurrence of somatic mutations that contribute to carcinogenesis. Ataxia telangiectasia (AT), Nijmegen breakage syndrome (NBS), and an ataxia-like disorder (ATLD), are chromosome instability disorders that are defective in the ataxia telangiectasia mutated (ATM), NBS, and Mre11 genes, respectively. These genes are critical in maintaining cellular resistance to ionizing radiation (IR), which kills largely by the production of double-strand breaks (DSBs). Bloom syndrome involves a defect in the BLM helicase, which seems to play a role in restarting DNA replication forks that are blocked at lesions, thereby promoting chromosome stability. The Werner syndrome gene (WRN) helicase, another member of the RecQ family like BLM, has very recently been found to help mediate homologous recombination. Fanconi anemia (FA) is a genetically complex chromosomal instability disorder involving seven or more genes, one of which is BRCA2. FA may be at least partially caused by the aberrant production of reactive oxidative species. The breast cancer-associated BRCA1 and BRCA2 proteins are strongly implicated in HRR; BRCA2 associates with Rad51 and appears to regulate its activity. We discuss in detail the phenotypes of the various mutant cell lines and the signaling pathways mediated by the ATM kinase. ATM's phosphorylation targets can be grouped into oxidative stress-mediated transcriptional changes, cell cycle checkpoints, and recombinational repair. We present the DNA damage response pathways by using the DSB as the prototype lesion, whose incorrect repair can initiate and augment karyotypic abnormalities.

Recombinational DNA repair and human disease

International Nuclear Information System (INIS)

Thompson, Larry H.; Schild, David

2002-01-01

We review the genes and proteins related to the homologous recombinational repair (HRR) pathway that are implicated in cancer through either genetic disorders that predispose to cancer through chromosome instability or the occurrence of somatic mutations that contribute to carcinogenesis. Ataxia telangiectasia (AT), Nijmegen breakage syndrome (NBS), and an ataxia-like disorder (ATLD), are chromosome instability disorders that are defective in the ataxia telangiectasia mutated (ATM), NBS, and Mre11 genes, respectively. These genes are critical in maintaining cellular resistance to ionizing radiation (IR), which kills largely by the production of double-strand breaks (DSBs). Bloom syndrome involves a defect in the BLM helicase, which seems to play a role in restarting DNA replication forks that are blocked at lesions, thereby promoting chromosome stability. The Werner syndrome gene (WRN) helicase, another member of the RecQ family like BLM, has very recently been found to help mediate homologous recombination. Fanconi anemia (FA) is a genetically complex chromosomal instability disorder involving seven or more genes, one of which is BRCA2. FA may be at least partially caused by the aberrant production of reactive oxidative species. The breast cancer-associated BRCA1 and BRCA2 proteins are strongly implicated in HRR; BRCA2 associates with Rad51 and appears to regulate its activity. We discuss in detail the phenotypes of the various mutant cell lines and the signaling pathways mediated by the ATM kinase. ATM's phosphorylation targets can be grouped into oxidative stress-mediated transcriptional changes, cell cycle checkpoints, and recombinational repair. We present the DNA damage response pathways by using the DSB as the prototype lesion, whose incorrect repair can initiate and augment karyotypic abnormalities

Mycobacterium tuberculosis DNA repair in response to subinhibitory concentrations of ciprofloxacin.

Science.gov (United States)

O'Sullivan, D M; Hinds, J; Butcher, P D; Gillespie, S H; McHugh, T D

2008-12-01

To investigate how the SOS response, an error-prone DNA repair pathway, is expressed following subinhibitory quinolone treatment of Mycobacterium tuberculosis. Genome-wide expression profiling followed by quantitative RT (qRT)-PCR was used to study the effect of ciprofloxacin on M. tuberculosis gene expression. Microarray analysis showed that 16/110 genes involved in DNA protection, repair and recombination were up-regulated. There appeared to be a lack of downstream genes involved in the SOS response. qRT-PCR detected an induction of lexA and recA after 4 h and of dnaE2 after 24 h of subinhibitory treatment. The pattern of gene expression observed following subinhibitory quinolone treatment differed from that induced after other DNA-damaging agents (e.g. mitomycin C). The expression of the DnaE2 polymerase response was significantly delayed following subinhibitory quinolone exposure.

Dissecting DNA repair in adult high grade gliomas for patient stratification in the post-genomic era

Science.gov (United States)

Perry, Christina; Agarwal, Devika; Abdel-Fatah, Tarek M.A.; Lourdusamy, Anbarasu; Grundy, Richard; Auer, Dorothee T.; Walker, David; Lakhani, Ravi; Scott, Ian S.; Chan, Stephen; Ball, Graham; Madhusudan, Srinivasan

2014-01-01

Deregulation of multiple DNA repair pathways may contribute to aggressive biology and therapy resistance in gliomas. We evaluated transcript levels of 157 genes involved in DNA repair in an adult glioblastoma Test set (n=191) and validated in ‘The Cancer Genome Atlas’ (TCGA) cohort (n=508). A DNA repair prognostic index model was generated. Artificial neural network analysis (ANN) was conducted to investigate global gene interactions. Protein expression by immunohistochemistry was conducted in 61 tumours. A fourteen DNA repair gene expression panel was associated with poor survival in Test and TCGA cohorts. A Cox multivariate model revealed APE1, NBN, PMS2, MGMT and PTEN as independently associated with poor prognosis. A DNA repair prognostic index incorporating APE1, NBN, PMS2, MGMT and PTEN stratified patients in to three prognostic sub-groups with worsening survival. APE1, NBN, PMS2, MGMT and PTEN also have predictive significance in patients who received chemotherapy and/or radiotherapy. ANN analysis of APE1, NBN, PMS2, MGMT and PTEN revealed interactions with genes involved in transcription, hypoxia and metabolic regulation. At the protein level, low APE1 and low PTEN remain associated with poor prognosis. In conclusion, multiple DNA repair pathways operate to influence biology and clinical outcomes in adult high grade gliomas. PMID:25026297

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.

Screen for genes involved in radiation survival of Escherichia coli and construction of a reference database

Energy Technology Data Exchange (ETDEWEB)

Sargentini, Neil J., E-mail: nsargentini@atsu.edu; Gularte, Nicholas P.; Hudman, Deborah A.

2016-11-15

-3 for 39 common mutants (P = 0.010). Comparing gene functions using MultiFun terms, uncommon genes tended to show less involvement in DNA repair-relevant categories (information transfer and cell processes), but greater involvement in seven other categories. Our analysis of 455 genes suggests cell survival and DNA repair processes are more complex than previously understood, and may be compromised by deficiencies in other processes.

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

DNA Repair Mechanism Gene, XRCC1A (Arg194Trp) but not XRCC3 (Thr241Met) Polymorphism Increased the Risk of Breast Cancer in Premenopausal Females: A Case–Control Study in Northeastern Region of India

Science.gov (United States)

Ahmed, Jishan; Narain, Kanwar; Mukherjee, Kaustab; Majumdar, Gautam; Chenkual, Saia; Zonunmawia, Jason C.

2017-01-01

X-ray repair cross complementary group gene is one of the most studied candidate gene involved in different types of cancers. Studies have shown that X-ray repair cross complementary genes are significantly associated with increased risk of breast cancer in females. Moreover, studies have revealed that X-ray repair cross complementary gene polymorphism significantly varies between and within different ethnic groups globally. The present case–control study was aimed to investigate the association of X-ray repair cross complementary 1A (Arg194Trp) and X-ray repair cross complementary 3 (Thr241Met) polymorphism with the risk of breast cancer in females from northeastern region of India. The present case–control study includes histopathologically confirmed and newly diagnosed 464 cases with breast cancer and 534 apparently healthy neighborhood community controls. Information on sociodemographic factors and putative risk factors were collected from each study participant by conducting face-to-face interviews. Genotyping of X-ray repair cross complementary 1A (Arg194Trp) and X-ray repair cross complementary 3 (Thr241Met) was carried out by polymerase chain reaction-restriction fragment length polymorphism. For statistical analysis, both univariate and multivariate logistic regression analyses were performed. We also performed stratified analysis to find out the association of X-ray repair cross complementary genes with the risk of breast cancer stratified based on menstrual status. This study revealed that tryptophan allele (R/W-W/W genotype) in X-ray repair cross complementary 1A (Arg194Trp) gene significantly increased the risk of breast cancer (adjusted odds ratio = 1.44, 95% confidence interval = 1.06-1.97, P India which may be beneficial for prognostic purposes. PMID:29332455

Relationship between radiation induced activation of DNA repair genes and radiation induced apoptosis in human cell line A431

International Nuclear Information System (INIS)

Bom, Hee Seung; Min, Jung Jun; Kim, Kyung Keun; Choi, Keun Hee

2000-01-01

The purpose of this study was to evaluate the relationship between radiation-induced acivation of DNA repair genes and radiation induced apoptosis in A431 cell line. Five and 25 Gys of gamma radiation were given to A431 cells by a Cs-137 cell irradiator. Apoptosis was evaluated by flow cytometry using annexin V-fluorescein isothiocyanate and propidium iodide staining. The expression of DNA repair genes was evaluated by both Northern and Western blot analyses. The number of apoptotic cells increased with the increased radiation dose. It increased most significantly at 12 hours after irradiation. Expression of p53, p21, and ℎRAD50 reached the highest level at 12 hours after 5 Gy irradiation. In response to 25 Gy irradiation, ℎRAD50 and p21 were expressed maximally at 12 hours, but p53 and GADD45 genes showed the highest expression level after 12 hours. Induction of apoptosis and DNA repair by ionizing radiation were closely correlated. The peak time of inducing apoptosis and DNA repair was 12 hours in this study model. ℎRAD50, a recently discovered DNA repair gene, was also associated with radiation-induced apoptosis.=20

Genetic polymorphisms in 19q13.3 genes associated with alteration of repair capacity to BPDE-DNA adducts in primary cultured lymphocytes.

Science.gov (United States)

Xiao, Mingyang; Xiao, Sha; Straaten, Tahar van der; Xue, Ping; Zhang, Guopei; Zheng, Xiao; Zhang, Qianye; Cai, Yuan; Jin, Cuihong; Yang, Jinghua; Wu, Shengwen; Zhu, Guolian; Lu, Xiaobo

2016-12-01

Benzo[a]pyrene(B[a]P), and its ultimate metabolite Benzo[a]pyrene 7,8-diol 9,10-epoxide (BPDE), are classic DNA damaging carcinogens. DNA damage in cells caused by BPDE is normally repaired by Nucleotide Excision Repair (NER) and Base Excision Repair (BER). Genetic variations in NER and BER can change individual DNA repair capacity to DNA damage induced by BPDE. In the present study we determined the number of in vitro induced BPDE-DNA adducts in lymphocytes, to reflect individual susceptibility to Polycyclic aromatic hydrocarbons (PAHs)-induced carcinogenesis. The BPDE-DNA adduct level in lymphocytes were assessed by high performance liquid chromatography (HPLC) in 281 randomly selected participants. We genotyped for 9 single nucleotide polymorphisms (SNPs) in genes involved in NER (XPB rs4150441, XPC rs2228001, rs2279017 and XPF rs4781560), BER (XRCC1 rs25487, rs25489 and rs1799782) and genes located on chromosome 19q13.2-3 (PPP1R13L rs1005165 and CAST rs967591). We found that 3 polymorphisms in chromosome 19q13.2-3 were associated with lower levels of BPDE-DNA adducts (MinorT allele in XRCC1 rs1799782, minor T allele in PPP1R13L rs1005165 and minor A allele in CAST rs967571). In addition, a modified comet assay was performed to further confirm the above conclusions. We found both minor T allele in PPP1R13L rs1005165 and minor A allele in CAST rs967571 were associated with the lower levels of BPDE-adducts. Our data suggested that the variant genotypes of genes in chromosome 19q13.2-3 are associated with the alteration of repair efficiency to DNA damage caused by Benzo[a]pyrene, and may contribute to enhance predictive value for individual's DNA repair capacity in response to environmental carcinogens. Copyright © 2016 Elsevier B.V. All rights reserved.

Genetic polymorphisms of DNA double-strand break repair pathway genes and glioma susceptibility

International Nuclear Information System (INIS)

Zhao, Peng; Zou, Peng; Zhao, Lin; Yan, Wei; Kang, Chunsheng; Jiang, Tao; You, Yongping

2013-01-01

Genetic variations in DNA double-strand break repair genes can influence the ability of a cell to repair damaged DNA and alter an individual’s susceptibility to cancer. We studied whether polymorphisms in DNA double-strand break repair genes are associated with an increased risk of glioma development. We genotyped 10 potentially functional single nucleotide polymorphisms (SNPs) in 7 DNA double-strand break repair pathway genes (XRCC3, BRCA2, RAG1, XRCC5, LIG4, XRCC4 and ATM) in a case–control study including 384 glioma patients and 384 cancer-free controls in a Chinese Han population. Genotypes were determined using the OpenArray platform. In the single-locus analysis there was a significant association between gliomas and the LIG4 rs1805388 (Ex2 +54C>T, Thr9Ile) TT genotype (adjusted OR, 3.27; 95% CI, 1.87-5.71), as well as the TC genotype (adjusted OR, 1.62; 95% CI, 1.20-2.18). We also found that the homozygous variant genotype (GG) of XRCC4 rs1805377 (IVS7-1A>G, splice-site) was associated with a significantly increased risk of gliomas (OR, 1.77; 95% CI, 1.12-2.80). Interestingly, we detected a significant additive and multiplicative interaction effect between the LIG4 rs1805388 and XRCC4 rs1805377 polymorphisms with an increasing risk of gliomas. When we stratified our analysis by smoking status, LIG4 rs1805388 was associated with an increased glioma risk among smokers. These results indicate for the first time that LIG4 rs1805388 and XRCC4 rs1805377, alone or in combination, are associated with a risk of gliomas

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.

55K isoform of CDK9 associates with Ku70 and is involved in DNA repair

International Nuclear Information System (INIS)

Liu, Hongbing; Herrmann, Christine H.; Chiang, Karen; Sung, Tzu-Ling; Moon, Sung-Hwan; Donehower, Lawrence A.; Rice, Andrew P.

2010-01-01

Positive elongation factor b (P-TEFb) is a cellular protein kinase that is required for RNA polymerase II (RNAP II) transcriptional elongation of protein coding genes. P-TEFb is a set of different molecular complexes, each containing CDK9 as the catalytic subunit. There are two isoforms of the CDK9 protein - the major 42 KDa CDK9 isoform and the minor 55KDa isoform that is translated from an in-frame mRNA that arises from an upstream transcriptional start site. We found that shRNA depletion of the 55K CDK9 protein in HeLa cells induces apoptosis and double-strand DNA breaks (DSBs). The levels of apoptosis and DSBs induced by the depletion were reduced by expression of a 55K CDK9 protein variant resistant to the shRNA, indicating that these phenotypes are the consequence of depletion of the 55K protein and not off-target effects. We also found that the 55K CDK9 protein, but not the 42K CDK9 protein, specifically associates with Ku70, a protein involved in DSB repair. Our findings suggest that the 55K CDK9 protein may function in repair of DNA through an association with Ku70.

Nuclear translocation contributes to regulation of DNA excision repair activities

DEFF Research Database (Denmark)

Knudsen, Nina Østergaard; Andersen, Sofie Dabros; Lützen, Anne

2009-01-01

for regulation of nuclear import that is necessary for proper localization of the repair proteins. This review summarizes the current knowledge on nuclear import mechanisms of DNA excision repair proteins and provides a model that categorizes the import by different mechanisms, including classical nuclear import......DNA mutations are circumvented by dedicated specialized excision repair systems, such as the base excision repair (BER), nucleotide excision repair (NER), and mismatch repair (MMR) pathways. Although the individual repair pathways have distinct roles in suppressing changes in the nuclear DNA......, it is evident that proteins from the different DNA repair pathways interact [Y. Wang, D. Cortez, P. Yazdi, N. Neff, S.J. Elledge, J. Qin, BASC, a super complex of BRCA1-associated proteins involved in the recognition and repair of aberrant DNA structures, Genes Dev. 14 (2000) 927-939; M. Christmann, M...

Rearrangement of Rag-1 recombinase gene in DNA-repair deficient/immunodeficient ``wasted`` mice

Energy Technology Data Exchange (ETDEWEB)

Woloschak, G.E.; Weaver, P.; Churchill, M.; Chang-Liu, C-M. [Argonne National Lab., IL (United States); Libertin, C.R. [Loyola Univ., Maywood, IL (United States)

1992-11-01

Mice recessive for the autosomal gene ``wasted`` (wst) display a disease pattern which includes increased sensitivity to the killing effects of ionizing radiation, immunodeficiency, and neurologic dysfunction. The recent cloning and characterization of recombinase genes (Rag-l/Rag-2) expressed in lymphoid and possibly central nervous system tissues prompted us to examine expression of these genes in DNA repair-deficient/immunodeficient wasted mice. Our results revealed that in thymus tissue, a small Rag-I transcript (1.0 kb) was detected in wst/wst mice that was not evident in thymus from control mice. In wst/{sm_bullet} mice, a two-fold increase in Rag-1 mRNA was evident in thymus tissue. Rag-2 mRNA could only be detected in thymus tissue from wst/{sm_bullet} and not from wst/wst or parental control BCF, mice. Southern blots revealed a rearrangement or deletion within the Rag-1 gene of affected wasted mice that was not evident in known strain-specific parental or littermate controls. These results support the idea that the Rag-1 gene may map at or near the locus for the wasted mutation. In addition, they suggest the importance of recombinase function in normal immune and central nervous system development as well as the potential contribution of this gene family to the normal repair of radiation-induced DNA damage.

Gastroesophageal junction adenocarcinoma displays abnormalities in homologous recombination and nucleotide excision repair

Directory of Open Access Journals (Sweden)

Dewalt RI

2014-02-01

Full Text Available Robin I Dewalt,1 Kenneth A Kesler,2 Zane T Hammoud,3 LeeAnn Baldridge,4 Eyas M Hattab,4 Shadia I Jalal1,5 1Division of Hematology/Oncology, Department of Medicine, 2Cardiothoracic Division, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA; 3Henry Ford Hospital, Detroit, MI, USA; 4Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA; 5Indiana University Melvin and Bren Simon Cancer Center, Indianapolis, IN, USA Objective: Esophageal adenocarcinoma (EAC continues to be a disease associated with high mortality. Among the factors leading to poor outcomes are innate resistance to currently available therapies, advanced stage at diagnosis, and complex biology. Platinum and ionizing radiation form the backbone of treatment for the majority of patients with EAC. Of the multiple processes involved in response to platinum chemotherapy or ionizing radiation, deoxyribonucleic acid (DNA repair has been a major player in cancer sensitivity to these agents. DNA repair defects have been described in various malignancies. The purpose of this study was to determine whether alterations in DNA repair are present in EAC compared with normal gastroesophageal tissues. Methods: We analyzed the expression of genes involved in homologous recombination (HR, nonhomologous end-joining, and nucleotide excision repair (NER pathways in 12 EAC tumor samples with their matched normal counterparts. These pathways were chosen because they are the main pathways involved in the repair of platinum- or ionizing-radiation-induced damage. In addition, abnormalities in these pathways have not been well characterized in EAC. Results: We identified increased expression of at least one HR gene in eight of the EAC tumor samples. Alterations in the expression of EME1, a structure-specific endonuclease involved in HR, were the most prevalent, with messenger (mRNA overexpression in six of the EAC samples

Involvement of DNA mismatch repair in the maintenance of heterochromatic DNA stability in Saccharomyces cerevisiae.

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Basanta K Dahal

2017-10-01

Full Text Available Heterochromatin contains a significant part of nuclear DNA. Little is known about the mechanisms that govern heterochromatic DNA stability. We show here that in the yeast Saccharomyces cerevisiae (i DNA mismatch repair (MMR is required for the maintenance of heterochromatic DNA stability, (ii MutLα (Mlh1-Pms1 heterodimer, MutSα (Msh2-Msh6 heterodimer, MutSβ (Msh2-Msh3 heterodimer, and Exo1 are involved in MMR at heterochromatin, (iii Exo1-independent MMR at heterochromatin frequently leads to the formation of Pol ζ-dependent mutations, (iv MMR cooperates with the proofreading activity of Pol ε and the histone acetyltransferase Rtt109 in the maintenance of heterochromatic DNA stability, (v repair of base-base mismatches at heterochromatin is less efficient than repair of base-base mismatches at euchromatin, and (vi the efficiency of repair of 1-nt insertion/deletion loops at heterochromatin is similar to the efficiency of repair of 1-nt insertion/deletion loops at euchromatin.

A Database to Support the Interpretation of Human Mismatch Repair Gene Variants

NARCIS (Netherlands)

Ou, Jianghua; Niessen, Renee C.; Vonk, Jan; Westers, Helga; Hofstra, Robert M. W.; Sijmons, Rolf H.

Germline mutations in the mismatch repair (MMR) genes MLH1, MSH2, MSH6, or PMS2 can cause Lynch syndrome. This syndrome, also known as hereditary nonpolyposis colorectal cancer (HNPCC), is an autosomal dominantly-inherited disorder predominantly characterized by colorectal and endometrial cancer.

Rearrangement of RAG-1 recombinase gene in DNA-repair deficient ``wasted`` mice

Energy Technology Data Exchange (ETDEWEB)

Woloschak, G.E.; Libertin, C.R.; Weaver, P. [Loyola Univ., Chicago, IL (United States); Churchill, M.; Chang-Liu, C.M. [Argonne National Lab., IL (United States)

1993-11-01

Mice recessive for the autosomal gene ``wasted`` wst display a disease pattern which includes increased sensitivity to the killing effects of ionizing radiation, immunodeficiency, and neurologic dysfunction. The recent cloning and characterization of recombinase genes (RAG-l/RAG-2) expressed in lymphoid and possibly central nervous system tissues prompted us to examine expression of these genes in DNA repair-deficient/immunodeficient wasted mice. Our results revealed expression of RAG-1 mRNA in spinal cord (but not brain) of control mice; no expression of RAG-1 mRNA was detected in spinal cord or brain from wst/wst mice or their normal littermates (wst/{center_dot}mice). In thymus tissue, a small RAG-1 transcript (1.0 kb) was detected in wst/wst mice that was not evident in thymus from control mice. In wst/{center_dot}mice, a two-fold increase in RAG-1 mRNA was evident in thymus tissue. RAG-2 mRNA could only be detected in thymus tissue from wst/{center_dot} and not from wst/wst or parental control BCF{sub 1} mice. Southern blots revealed a rearrangement/deletion within the RAG-1 gene of affected wasted mice, not evident in known strain-specific parental or littermate controls. These results support the idea that the RAG-1 gene may map at or near the locus for the wasted mutation. In addition, they suggest the importance of recombinase function in normal immune and central nervous system development as well as the potential contribution of this gene family to the normal repair of radiation-induced DNA damage.

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.

Cloning of the DNA Repair Gene, Uvsf, by Transformation of Aspergillus Nidulans

OpenAIRE

Oza, K.; Kafer, E.

1990-01-01

As a first step in the cloning of the DNA repair gene uvsF of Aspergillus nidulans, uvsF pyrG double mutant strains were transformed with a genomic library which carried the complementing Neurospora pyr-4 gene in the vector. Rare pyr(+) uvs(+) cotransformants were obtained on media lacking pyrimidines, overlayed with MMS (methyl-methane sulfonate) to which uvsF is hypersensitive. Among MMS-resistant transformants, Southerns revealed two types which showed single bands of different sizes when ...

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

International Nuclear Information System (INIS)

Perrin, A.; Bachelet, C.; Fournier, C.; Peinnequin, A.; Leveque, P.; Collin, A.

2006-01-01

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

Inhibition of potential lethal damage repair and related gene expression after carbon-ion beam irradiation to human lung cancer grown in nude mice

International Nuclear Information System (INIS)

Yashiro, Tomoyasu; Fujisawa, Takehiko; Koyama-Saegusa, Kumiko; Imai, Takashi; Miyamoto, Tadaaki

2007-01-01

Using cultured and nude mouse tumor cells (IA) derived from a human lung cancer, we previously demonstrated their radiosensitivity by focusing attention on the dynamics of tumor clonogens and the early and rapid survival recovery (potential lethal damage repair: PLD repair) occurring after X-ray irradiation. To the authors' knowledge, this is the first study demonstrating gene expression in association with PLD repair after carbon-ion beam or X-ray irradiation to cancer cells. In this study we tried to detect the mechanism of DNA damage and repair of the clonogens after X-ray or carbon-ion beam irradiation. At first, colony assay method was performed after irradiation of 12 Gy of X-ray or 5 Gy of carbon-ion beam to compare the time dependent cell survival of the IA cells after each irradiation pass. Second, to search the genes causing PLD repair after irradiation of X-ray or carbon-ion beam, we evaluated gene expressions by using semi-quantitative RT-PCR with the selected 34 genes reportedly related to DNA repair. The intervals from the irradiation were 0, 6, 12 and 24 hr for colony assay method, and 0, 3, 18 hr for RT-PCR method. From the result of survival assays, significant PLD repair was not observed in carbon-ion beam as compared to X-ray irradiation. The results of RT-PCR were as follows. The gene showing significantly higher expressions after X-ray irradiation than after carbon-ion beam irradiation was PCNA. The genes showing significantly lower expressions after X-ray irradiation rather than after carbon-ion beam irradiation were RAD50, BRCA1, MRE11A, XRCC3, CHEK1, MLH1, CCNB1, CCNB2 and LIG4. We conclude that PCNA could be a likely candidate gene for PLD repair. (author)

Three additional genes involved in pyrimidine dimer removal in Saccharomyces cerevisiae: RAD7, RAD14, and MMS19

Energy Technology Data Exchange (ETDEWEB)

Prakash, L; Prakash, S

1979-01-01

The ability to remove ultraviolet (uv)-induced pyrimidine dimers from the nuclear DNA of yeast was examined in two radiation-sensitive (rad) mutants and one methyl methanesulfonate-sensitive (mms) mutant of the yeast Saccharomyces cerevisiae. The susceptibility of DNA from irradiated cells to nicking by an endonuclease activity prepared from crude extracts of Micrococcus luteus was used to measure the presence of dimers in DNA. The rad7, rad14, and mms19 mutants were found to be defective in their ability to remove uv-induced dimers from nuclear DNA. All three mutants belong to the same episatic group as the other mutants involved in excision-repair. All three mutants show enhanced uv-induced mutations. The rad 14 mutant also shows epistatic interactions with genes in the other two uv repair pathways.

DNA polymerase I-mediated ultraviolet repair synthesis in toluene-treated Escherichia coli

International Nuclear Information System (INIS)

Dorson, J.W.; Moses, R.E.

1978-01-01

DNA synthesis after ultraviolet irradiation is low in wild type toluene-treated cells. The level of repair incorporation is greater in strains deficient in DNA polymerase I. The low level of repair synthesis is attributable to the concerted action of DNA polymerase I and polynucleotide ligase. Repair synthesis is stimulated by blocking ligase activity with the addition of nicotinamide mononucleotide (NMN) or the use of a ligase temperature-sensitive mutant. NMN stimulation is specific for DNA polymerase I-mediated repair synthesis, as it is absent in isogenic strains deficient in the polymerase function or the 5' yields 3' exonuclease function associated with DNA polymerase I. DNA synthesis that is stimulated by NMN is proportional to the ultraviolet exposure at low doses, nonconservative in nature, and is dependent on the uvrA gene product but is independent of the recA gene product. These criteria place this synthesis in the excision repair pathway. The NMN-stimulated repair synthesis requires ATP and is N-ethylmaleimide-resistant. The use of NMN provides a direct means for evaluating the involvement of DNA polymerase I in excision repair

Genetic variation in a DNA double strand break repair gene in saudi population: a comparative study with worldwide ethnic groups.

Science.gov (United States)

Areeshi, Mohammed Yahya

2013-01-01

DNA repair capacity is crucial in maintaining cellular functions and homeostasis. However, it can be altered based on DNA sequence variations in DNA repair genes and this may lead to the development of many diseases including malignancies. Identification of genetic polymorphisms responsible for reduced DNA repair capacity is necessary for better prevention. Homologous recombination (HR), a major double strand break repair pathway, plays a critical role in maintaining the genome stability. The present study was performed to determine the frequency of the HR gene XRCC3 Exon 7 (C18067T, rs861539) polymorphisms in Saudi Arabian population in comparison with epidemiological studies by "MEDLINE" search to equate with global populations. The variant allelic (T) frequency of XRCC3 (C>T) was found to be 39%. Our results suggest that frequency of XRCC3 (C>T) DNA repair gene exhibits distinctive patterns compared with the Saudi Arabian population and this might be attributed to ethnic variation. The present findings may help in high-risk screening of humans exposed to environmental carcinogens and cancer predisposition in different ethnic groups.

Characterization of RAD4 gene required for ultraviolet-induced excision repair of Saccharomyces cerevisiae propagated in Escherichia coli without inactivation

International Nuclear Information System (INIS)

Choi, I.S.; Kim, J.B.; Lee, K.N.; Park, S.D.

1990-01-01

The previously isolated RAD4 gene designated as pPC1 from the genomic library of Saccharomyces cerevisiae appeared to propagate in Escherichia coli and yet retained its complementing activity of rad4 mutants without inactivation. The subcloned RAD4 gene was found to be localized within a 2.5 kb DNA fragment flanking Bg/II and BamHI sites in the insert DNA, and was shown to have the same restriction map as a yeast chromosomal DNA, as determined by Southern hybridization. Tetrad analysis and pulse-field chromosome mapping have revealed that the cloned RAD4 gene can be mapped and integrated into the yeast chromosome V, the actual site of this gene. DNA-tRNA hybridization has shown that the isolated RAD4 gene did not contain a suppressor tRNA gene. These results have indicated that the pPC1 is a functional RAD4 gene playing a unique role involved in the nucleotide excision repair of yeast without any genetic change during amplification in E. coli. (author)

Tissue repair genes: the TiRe database and its implication for skin wound healing

OpenAIRE

Yanai, Hagai; Budovsky, Arie; Tacutu, Robi; Barzilay, Thomer; Abramovich, Amir; Ziesche, Rolf; Fraifeld, Vadim E.

2016-01-01

Wound healing is an inherent feature of any multicellular organism and recent years have brought about a huge amount of data regarding regular and abnormal tissue repair. Despite the accumulated knowledge, modulation of wound healing is still a major biomedical challenge, especially in advanced ages. In order to collect and systematically organize what we know about the key players in wound healing, we created the TiRe (Tissue Repair) database, an online collection of genes and proteins that ...

The essential DNA polymerases δ and ε are involved in repair of UV-damaged DNA in the yeast Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Halas, A.; Policinska, Z.; Baranowska, H.; Jachymczyk, W.J.

1999-01-01

We have studied the ability of yeast DNA polymerases to carry out repair of lesions caused by UV irradiation in Saccharomyces cerevisiae. By the analysis of postirradiation relative molecular mass changes in cellular DNA of different DNA polymerases mutant strains, it was established that mutations in DNA polymerases δ and ε showed accumulation of single-strand breaks indicating defective repair. Mutations in other DNA polymerase genes exhibited no defects in DNA repair. Thus, the data obtained suggest that DNA polymerases δ and ε are both necessary for DNA replication and for repair of lesions caused by UV irradiation. The results are discussed in the light of current concepts concerning the specificity of DNA polymerases in DNA repair. (author)

Microsatellite Instability Use in Mismatch Repair Gene Sequence Variant Classification

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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.

Role of Rad54, Rad54b and Snm1 in DNA damage repair

NARCIS (Netherlands)

J. Wesoly (Joanna)

2003-01-01

textabstractThe aim of this thesis is to investigate the function of a number of genes involved in mammalian DNA damage repair, in particular in repair of DNA double-strand breaks (DSBs). Among a large number of different damages that can be introduced to DNA, DSBs are especially toxic. If

Fanconi anemia (cross)linked to DNA repair.

Science.gov (United States)

Niedernhofer, Laura J; Lalai, Astrid S; Hoeijmakers, Jan H J

2005-12-29

Fanconi anemia is characterized by hypersensitivity to DNA interstrand crosslinks (ICLs) and susceptibility to tumor formation. Despite the identification of numerous Fanconi anemia (FANC) genes, the mechanism by which proteins encoded by these genes protect a cell from DNA interstrand crosslinks remains unclear. The recent discovery of two DNA helicases that, when defective, cause Fanconi anemia tips the balance in favor of the direct involvement of the FANC proteins in DNA repair and the bypass of DNA lesions.

The Saccharomyces cerevisiae RAD30 gene, a homologue of Escherichia coli dinB and umuC, is DNA damage inducible and functions in a novel error-free postreplication repair mechanism

Energy Technology Data Exchange (ETDEWEB)

McDonald, J. P. [NIH, Bethesda, MD. (United States); Levine, A. S.; Woodgate, R.

1997-12-15

Damage-inducible mutagenesis in prokaryotes is largely dependent upon the activity of the UmuD'C-like proteins. Since many DNA repair processes are structurally and/or functionally conserved between prokaryotes and eukaryotes, we investigated the role of RAD30, a previously uncharacterized Saccharomyces cerevisiae DNA repair gene related to the Escherichia coli dinB, umuC and S. cerevisiae REV1 genes, in UV resistance and UV-induced mutagenesis. Similar to its prokaryotic homologues, RAD30 was found to be damage inducible. Like many S. cerevisiae genes involved in error-prone DNA repair, epistasis analysis clearly places RAD30 in the RAD6 group and rad30 mutants display moderate UV sensitivity reminiscent of rev mutants. However, unlike rev mutants, no defect in UV-induced reversion was seen in rad30 strains. While rad6 and rad18 are both epistatic to rad30, no epistasis was observed with rev1, rev3, rev7 or rad5, all of which are members of the RAD6 epistasis group. These findings suggest that RD30 participates in a novel error-free repair pathway dependent on RAD6 and RAD18, but independent of REV1, REV3, REV7 and RAD5. (author)

Repair-defective mutants of Alteromonas espejiana, the host for bacteriophage PM2

International Nuclear Information System (INIS)

Zerler, B.R.; Wallace, S.S.

1984-01-01

The in vivo repair processes of Alteromonas espejiana, the host for bacteriophage PM2, were characterized, and UV- and methyl methanesulfonate (MMS)-sensitive mutants were isolated. Wild-type A. espejiana cells were capable of photoreactivation, excision, recombination, and inducible repair. There was no detecttable pyrimidine dimer-DNA N-glycosylase activity, and pyrimidine dimer removal appeared to occur by a pathway analogous to the Escherichia coli Uvr pathway. The UV- and MMS-sensitive mutants of A. espejiana included three groups, each containing at least one mutation involved with excision, recombination, or inducible repair. One group that was UV sensitive but not sensitive to MMS or X rays showed a decreased ability to excise pyrimidine dimers. Mutants in this group were also sensitive to psoralen plus near-UV light and were phenotypically analogous to the E. coli uvr mutants. A second group was UV and MMS sensitive but not sensitive to X rays and appeared to contain mutations in a gene(s) involved in recombination repair. These recombination-deficient mutants differed from the E. coli rec mutants, which are MMS and X-ray sensitive. The third group of A. espejiana mutants was sensitive to UV, MMS, and X rays. These mutants were recombination deficient, lacked inducible repair, and were phenotypically similar to E. coli recA mutants

Cloning and characterization of p52, the fifth subunit of the core of transcription/repair factor TFIIH.

NARCIS (Netherlands)

J.C. Marinoni; R. Roy (Richard); W. Vermeulen (Wim); P. Miniou; Y. Lutz; G. Weeda (Geert); T. Seroz; D.M. Gomez (Denise Molina); J.H.J. Hoeijmakers (Jan); J-M. Egly (Jean-Marc)

1997-01-01

textabstractTFIIH is a multiprotein factor involved in transcription and DNA repair and is implicated in DNA repair/transcription deficiency disorders such as xeroderma pigmentosum, Cockayne syndrome and trichothiodystrophy. Eight out of the nine genes encoding the subunits forming TFIIH have

Identification of Region-Specific Myocardial Gene Expression Patterns in a Chronic Swine Model of Repaired Tetralogy of Fallot.

Directory of Open Access Journals (Sweden)

Sabine Charron

Full Text Available Surgical repair of Tetralogy of Fallot (TOF is highly successful but may be complicated in adulthood by arrhythmias, sudden death, and right ventricular or biventricular dysfunction. To better understand the molecular and cellular mechanisms of these delayed cardiac events, a chronic animal model of postoperative TOF was studied using microarrays to perform cardiac transcriptomic studies. The experimental study included 12 piglets (7 rTOF and 5 controls that underwent surgery at age 2 months and were further studied after 23 (+/- 1 weeks of postoperative recovery. Two distinct regions (endocardium and epicardium from both ventricles were analyzed. Expression levels from each localization were compared in order to decipher mechanisms and signaling pathways leading to ventricular dysfunction and arrhythmias in surgically repaired TOF. Several genes were confirmed to participate in ventricular remodeling and cardiac failure and some new candidate genes were described. In particular, these data pointed out FRZB as a heart failure marker. Moreover, calcium handling and contractile function genes (SLN, ACTC1, PLCD4, PLCZ, potential arrhythmia-related genes (MYO5B, KCNA5, and cytoskeleton and cellular organization-related genes (XIRP2, COL8A1, KCNA6 were among the most deregulated genes in rTOF ventricles. To our knowledge, this is the first comprehensive report on global gene expression profiling in the heart of a long-term swine model of repaired TOF.

Repair replication in permeabilized Escherichia coli

International Nuclear Information System (INIS)

Masker, W.E.; Simon, T.J.; Hanawalt, P.C.

1975-01-01

We have examined the modes of DNA synthesis in Escherichia coli strains made permeable to nucleoside triphosphates by treatment with toluene. In this quasi in vitro system, polymerase-I-deficient mutants exhibit a nonconservative mode of synthesis with properties expected for the resynthesis step of excision-repair. This uv-stimulated DNA synthesis can be performed by either DNA polymerase II or III and it also requires the uvrA gene product. It requires the four deoxynucleoside triphosphates; but, in contrast to the semiconservative mode, the ATP requirement can be partially satisfied by other nucleoside triphosphates. The ATP-dependent recBC nuclease is not involved. The observed uv-stimulated mode of DNA synthesis may be part of an alternate excision-repair mechanism which supplements or complements DNA-polymerase-I-dependent repair in vivo

Activated RecA protein may induce expression of a gene that is not controlled by the LexA repressor and whose function is required for mutagenesis and repair of UV-irradiated bacteriophage lambda

International Nuclear Information System (INIS)

Calsou, P.; Villaverde, A.; Defais, M.

1987-01-01

The activated form of the RecA protein (RecA) is known to be involved in the reactivation and mutagenesis of UV-irradiated bacteriophage lambda and in the expression of the SOS response in Escherichia coli K-12. The expression of the SOS response requires cleavage of the LexA repressor by RecA and the subsequent expression of LexA-controlled genes. The evidence presented here suggests that RecA induces the expression of a gene(s) that is not under LexA control and that is also necessary for maximal repair and mutagenesis of damaged phage. This conclusion is based on the chloramphenicol sensitivity of RecA -dependent repair and mutagenesis of damaged bacteriophage lambda in lexA(Def) hosts

Restoration of u.v.-induced excision repair in Xeroderma D cells transfected with the denV gene of bacteriophage T4

International Nuclear Information System (INIS)

Arrand, J.E.; Squires, S.; Bone, N.M.; Johnson, R.T.

1987-01-01

The heritable DNA repair defect in human Xeroderma D cells, resulting in failure to incise at u.v. light-induced pyrimidine dimers, has been partially but stably corrected by transfection of immortalised cells with the denV pyrimidine dimer glycosylase gene of bacteriophage T4. Transfectants selected either for a dominant marker on the mammalian vector carrying the prokaryotic gene or for dominant marker plus resistance to killing by u.v. light, were shown to express the denV gene to varying degrees. denV expression results in significant phenotypic change in the initially repair-deficient, u.v.-hypersensitive cells. Increased resistance to u.v. light and more rapid recovery of replicative DNA synthesis following u.v. irradiation were correlated with improved repair DNA synthesis and with a novel dimer incision capability present in denV transfected Xeroderma cells but not as evident in transfected normal cells. Most transfectants contain a single integrated copy of the denV gene; increase in denV copy number does not result in either increased gene expression or enhanced survival to u.v. light. Results show that expression of a heterologous prokaryotic repair gene can partially compensate for the genetic defect in a human Xeroderma D cell. (author)

DNA repair in the c-myc proto-oncogene locus: Possible involvement in susceptibility or resistance to plasmacytoma induction in BALB/c mice

International Nuclear Information System (INIS)

Beecham, E.J.; Mushinski, J.F.; Shacter, E.; Potter, M.; Bohr, V.A.

1991-01-01

This report describes an unexpected difference in the efficiency of removal of UV-induced DNA damage in the c-myc locus in splenic B lymphoblasts from two inbred strains of mice. In cells from plasmacytoma-resistant DBA/2N mice, 35% of UV-induced damage in the regulatory and 5' flank of c-myc is removed by 12 h. However, in cells from plasmacytoma-susceptible BALB/cAn mice, damage is not removed from this region. In the protein-encoding region and 3' flank of c-myc as well as in two dihydrofolate reductase gene fragments, UV damage is repaired with similar efficiency in B lymphoblasts from both strains of mice. Furthermore, in the protein-encoding portion and 3' flank of c-myc, damage is selectively removed from only the transcribed strand. No repair is detected in the nontranscribed strand. In contrast, DNA repair in the 5' flank of c-myc is not strand specific; in DNA from DBA/2N cells, UV damage is rapidly removed from both the transcribed and nontranscribed strands. In BALB/cAn cells no repair was detected in either strand in the 5'flank, consistent with the results with double-stranded, nick-translated probes to this region of c-myc. In addition to the repair studies, we have detected post-UV-damage formation: in most of the genes studied, we find that additional T4 endonuclease-sensitive sites are formed in the DNA 2 h after irradiation. Our findings provide new insights into the details of gene-specific and strand-specific DNA repair and suggest that there may be close links between DNA repair and B-cell neoplastic development

Coevolution between Nuclear-Encoded DNA Replication, Recombination, and Repair Genes and Plastid Genome Complexity.

Science.gov (United States)

Zhang, Jin; Ruhlman, Tracey A; Sabir, Jamal S M; Blazier, John Chris; Weng, Mao-Lun; Park, Seongjun; Jansen, Robert K

2016-02-17

Disruption of DNA replication, recombination, and repair (DNA-RRR) systems has been hypothesized to cause highly elevated nucleotide substitution rates and genome rearrangements in the plastids of angiosperms, but this theory remains untested. To investigate nuclear-plastid genome (plastome) coevolution in Geraniaceae, four different measures of plastome complexity (rearrangements, repeats, nucleotide insertions/deletions, and substitution rates) were evaluated along with substitution rates of 12 nuclear-encoded, plastid-targeted DNA-RRR genes from 27 Geraniales species. Significant correlations were detected for nonsynonymous (dN) but not synonymous (dS) substitution rates for three DNA-RRR genes (uvrB/C, why1, and gyrA) supporting a role for these genes in accelerated plastid genome evolution in Geraniaceae. Furthermore, correlation between dN of uvrB/C and plastome complexity suggests the presence of nucleotide excision repair system in plastids. Significant correlations were also detected between plastome complexity and 13 of the 90 nuclear-encoded organelle-targeted genes investigated. Comparisons revealed significant acceleration of dN in plastid-targeted genes of Geraniales relative to Brassicales suggesting this correlation may be an artifact of elevated rates in this gene set in Geraniaceae. Correlation between dN of plastid-targeted DNA-RRR genes and plastome complexity supports the hypothesis that the aberrant patterns in angiosperm plastome evolution could be caused by dysfunction in DNA-RRR systems. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

denV gene of bacteriophage T4 restores DNA excision repair to mei-9 and mus201 mutants of Drosophila melanogaster

International Nuclear Information System (INIS)

Banga, S.S.; Boyd, J.B.; Valerie, K.; Harris, P.V.; Kurz, E.M.; de Riel, J.K.

1989-01-01

The denV gene of bacteriophage T4 was fused to a Drosophila hsp70 (70-kDa heat shock protein) promoter and introduced into the germ line of Drosophila by P-element-mediated transformation. The protein product of that gene (endonuclease V) was detected in extracts of heat-shocked transformants with both enzymological and immunoblotting procedures. That protein restores both excision repair and UV resistance to mei-9 and mus201 mutants of this organism. These results reveal that the denV gene can compensate for excision-repair defects in two very different eukayotic mutants, in that the mus201 mutants are typical of excision-deficient mutants in other organisms, whereas the mei-9 mutants exhibit a broad pleiotropism that includes a strong meiotic deficiency. This study permits an extension of the molecular analysis of DNA repair to the germ line of higher eukaryotes. It also provides a model system for future investigations of other well-characterized microbial repair genes on DNA damage in the germ line of this metazoan organism

Regulatory network analysis of Epstein-Barr virus identifies functional modules and hub genes involved in infectious mononucleosis.

Science.gov (United States)

Poorebrahim, Mansour; Salarian, Ali; Najafi, Saeideh; Abazari, Mohammad Foad; Aleagha, Maryam Nouri; Dadras, Mohammad Nasr; Jazayeri, Seyed Mohammad; Ataei, Atousa; Poortahmasebi, Vahdat

2017-05-01

Epstein-Barr virus (EBV) is the most common cause of infectious mononucleosis (IM) and establishes lifetime infection associated with a variety of cancers and autoimmune diseases. The aim of this study was to develop an integrative gene regulatory network (GRN) approach and overlying gene expression data to identify the representative subnetworks for IM and EBV latent infection (LI). After identifying differentially expressed genes (DEGs) in both IM and LI gene expression profiles, functional annotations were applied using gene ontology (GO) and BiNGO tools, and construction of GRNs, topological analysis and identification of modules were carried out using several plugins of Cytoscape. In parallel, a human-EBV GRN was generated using the Hu-Vir database for further analyses. Our analysis revealed that the majority of DEGs in both IM and LI were involved in cell-cycle and DNA repair processes. However, these genes showed a significant negative correlation in the IM and LI states. Furthermore, cyclin-dependent kinase 2 (CDK2) - a hub gene with the highest centrality score - appeared to be the key player in cell cycle regulation in IM disease. The most significant functional modules in the IM and LI states were involved in the regulation of the cell cycle and apoptosis, respectively. Human-EBV network analysis revealed several direct targets of EBV proteins during IM disease. Our study provides an important first report on the response to IM/LI EBV infection in humans. An important aspect of our data was the upregulation of genes associated with cell cycle progression and proliferation.

Molecular cloning and analysis of DNA repair gene from the radioresistant bacterium deinococcus radiodurans

International Nuclear Information System (INIS)

Du Zeji; Wang Mingsuo

1998-12-01

Deinococcus radiodurans (Dr) possesses a prominent ability to repair DNA injury induced by various DNA-damaging agents including mitomycin C (MC), ultraviolet light (UV) and ionizing radiation. A DNA repair mutant Dr KH3111 is a streptomycin resistant (Sm R ) derivative of KH311 which is generated by treatment with nitrosoguanidine and is sensitive to MC, 8-trimethyl-psoralen, UV and γ-ray irradiation. Gene affected by a mutation in the mutant is identified and its nucleotide sequence is determined. A complete open reading frame (ORF) which encompassed the KH3111 mutation region is found and tentatively designated as orf144b. The deduced amino acid (aa) sequence of orf144b consists of 284 aa and has no significant homology to other known proteins. The exact KH3111 mutation site is one nucleotide altered (G to A) in the sequence of orf144b in the mutant. The KH3111 mutation causes the substitution of Gly for Glu at aa position 149 of Orf144b. Survival measurements of a revertant KH3112 which was produced by transforming with DNA containing a part of the orf144b gene of KD8301 showed that the resistances to MC, UV and γ-ray in the revertant were fully restored at a level equal to the wild type. Thus, the orf144b gene required for the multiple-DNA-damaging agent resistance of Dr was designated with the name of pprA (Pleiotropic gene promoting DNA repair). This new gene can express in E. coli at very high level, and make the host E. coli resistant to MC, UV and γ-ray. The pprA gene does not express in normal Dr, but it can be induced to express by treatment with MC, UV and γ-ray. It was thought that the PprA polypeptide is a cytoplasmic protein because of the absence of characteristics found in the aa sequence of membrane proteins

Identification of genes involved in low aminoglycoside-induced SOS response in Vibrio cholerae: a role for transcription stalling and Mfd helicase.

Science.gov (United States)

Baharoglu, Zeynep; Babosan, Anamaria; Mazel, Didier

2014-02-01

Sub-inhibitory concentrations (sub-MIC) of antibiotics play a very important role in selection and development of resistances. Unlike Escherichia coli, Vibrio cholerae induces its SOS response in presence of sub-MIC aminoglycosides. A role for oxidized guanine residues was observed, but the mechanisms of this induction remained unclear. To select for V. cholerae mutants that do not induce low aminoglycoside-mediated SOS induction, we developed a genetic screen that renders induction of SOS lethal. We identified genes involved in this pathway using two strategies, inactivation by transposition and gene overexpression. Interestingly, we obtained mutants inactivated for the expression of proteins known to destabilize the RNA polymerase complex. Reconstruction of the corresponding mutants confirmed their specific involvement in induction of SOS by low aminoglycoside concentrations. We propose that DNA lesions formed on aminoglycoside treatment are repaired through the formation of single-stranded DNA intermediates, inducing SOS. Inactivation of functions that dislodge RNA polymerase leads to prolonged stalling on these lesions, which hampers SOS induction and repair and reduces viability under antibiotic stress. The importance of these mechanisms is illustrated by a reduction of aminoglycoside sub-MIC. Our results point to a central role for transcription blocking at DNA lesions in SOS induction, so far underestimated.

New polymorphisms of Xeroderma Pigmentosum DNA repair genes in myelodysplastic syndrome.

Science.gov (United States)

Santiago, Sabrina Pinheiro; Junior, Howard Lopes Ribeiro; de Sousa, Juliana Cordeiro; de Paula Borges, Daniela; de Oliveira, Roberta Taiane Germano; Farias, Izabelle Rocha; Costa, Marília Braga; Maia, Allan Rodrigo Soares; da Nóbrega Ito, Mayumi; Magalhães, Silvia Maria Meira; Pinheiro, Ronald Feitosa

2017-07-01

The association between Xeroderma Pigmentosum DNA repair genes (XPA rs1800975, XPC rs2228000, XPD rs1799793 and XPF rs1800067) polymorphisms and myelodysplastic syndrome (MDS) have not been reported. To assess the functional role between these polymorphisms and MDS, we evaluated 189 samples stratified in two groups: 95 bone marrow samples from MDS patients and 94 from healthy elderly volunteers used as controls. Genotypes for all polymorphisms were identified in DNA samples in an allelic discrimination experiment by real-time polymerase chain reaction (qPCR). We also studied the mRNA expression of XPA and XPC genes to evaluate if its polymorphisms were functional in 53 RNAm MDS patients by qPCR methodologies. To the rs2228000 polymorphism, the CT and TT polymorphic genotype were associated with increased odds ratio (OR) of more profound cytopenia (hemoglobin and neutrophils count). To the rs1799793 polymorphism, we found that the GG homozygous wild-type genotype was associated with a decreased chance of developing MDS. We observed low expression of XPA in younger patients, in hypoplastic MDS and patients with abnormal karyotype when presented AG or AA polymorphic genotypes. We also found that there was a statistically significant interaction between the presence of micromegakaryocyte on down regulation of XPC regarding the CT heterozygous genotype of the rs1800975 polymorphism. Our results suggest that new functional polymorphisms of Xeroderma Pigmentosum DNA repair genes in MDS are related to its pathogenesis and prognosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

CEBPG transcription factor correlates with antioxidant and DNA repair genes in normal bronchial epithelial cells but not in individuals with bronchogenic carcinoma

International Nuclear Information System (INIS)

Mullins, D'Anna N; Crawford, Erin L; Khuder, Sadik A; Hernandez, Dawn-Alita; Yoon, Youngsook; Willey, James C

2005-01-01

Cigarette smoking is the primary cause of bronchogenic carcinoma (BC), yet only 10–15% of heavy smokers develop BC and it is likely that this variation in risk is, in part, genetically determined. We previously reported a set of antioxidant genes for which transcript abundance was lower in normal bronchial epithelial cells (NBEC) of BC individuals compared to non-BC individuals. In unpublished studies of the same NBEC samples, transcript abundance values for several DNA repair genes were correlated with these antioxidant genes. From these data, we hypothesized that antioxidant and DNA repair genes are co-regulated by one or more transcription factors and that inter-individual variation in expression and/or function of one or more of these transcription factors is responsible for inter-individual variation in risk for BC. The putative transcription factor recognition sites common to six of the antioxidant genes were identified through in silico DNA sequence analysis. The transcript abundance values of these transcription factors (n = 6) and an expanded group of antioxidant and DNA repair genes (n = 16) were measured simultaneously by quantitative PCR in NBEC of 24 non-BC and 25 BC individuals. CEBPG transcription factor was significantly (p < 0.01) correlated with eight of the antioxidant or DNA repair genes in non-BC individuals but not in BC individuals. In BC individuals the correlation with CEBPG was significantly (p < 0.01) lower than that of non-BC individuals for four of the genes (XRCC1, ERCC5, GSTP1, and SOD1) and the difference was nearly significant for GPX1. The only other transcription factor correlated with any of these five target genes in non-BC individuals was E2F1. E2F1 was correlated with GSTP1 among non-BC individuals, but in contrast to CEBPG, there was no significant difference in this correlation in non-BC individuals compared to BC individuals. We conclude that CEBPG is the transcription factor primarily responsible for regulating

Variations in mismatch repair genes and colorectal cancer risk and clinical outcome

Czech Academy of Sciences Publication Activity Database

Vymetálková, Veronika; Pardini, B.; Rosa, F.; Di Gaetano, C.; Novotný, J.; Levý, M.; Buchler, T.; Slyšková, Jana; Vodičková, Ludmila; Naccarati, Alessio; Vodička, Pavel

2014-01-01

Roč. 29, č. 4 (2014), s. 259-265 ISSN 0267-8357 R&D Projects: GA ČR GPP304/11/P715; GA ČR GAP304/10/1286; GA MZd NT12025 Institutional support: RVO:68378041 Keywords : colorectal cancer , , * mismatch repair genes * miRNA Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.793, year: 2014

Apolipoprotein gene involved in lipid metabolism

Science.gov (United States)

Rubin, Edward; Pennacchio, Len A.

2007-07-03

Methods and materials for studying the effects of a newly identified human gene, APOAV, and the corresponding mouse gene apoAV. The sequences of the genes are given, and transgenic animals which either contain the gene or have the endogenous gene knocked out are described. In addition, single nucleotide polymorphisms (SNPs) in the gene are described and characterized. It is demonstrated that certain SNPs are associated with diseases involving lipids and triglycerides and other metabolic diseases. These SNPs may be used alone or with SNPs from other genes to study individual risk factors. Methods for intervention in lipid diseases, including the screening of drugs to treat lipid-related or diabetic diseases are also disclosed.

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.

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 Internatio......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...

DNA Damage, Repair, and Cancer Metabolism

Science.gov (United States)

Turgeon, Marc-Olivier; Perry, Nicholas J. S.; Poulogiannis, George

2018-01-01

Although there has been a renewed interest in the field of cancer metabolism in the last decade, the link between metabolism and DNA damage/DNA repair in cancer has yet to be appreciably explored. In this review, we examine the evidence connecting DNA damage and repair mechanisms with cell metabolism through three principal links. (1) Regulation of methyl- and acetyl-group donors through different metabolic pathways can impact DNA folding and remodeling, an essential part of accurate double strand break repair. (2) Glutamine, aspartate, and other nutrients are essential for de novo nucleotide synthesis, which dictates the availability of the nucleotide pool, and thereby influences DNA repair and replication. (3) Reactive oxygen species, which can increase oxidative DNA damage and hence the load of the DNA-repair machinery, are regulated through different metabolic pathways. Interestingly, while metabolism affects DNA repair, DNA damage can also induce metabolic rewiring. Activation of the DNA damage response (DDR) triggers an increase in nucleotide synthesis and anabolic glucose metabolism, while also reducing glutamine anaplerosis. Furthermore, mutations in genes involved in the DDR and DNA repair also lead to metabolic rewiring. Links between cancer metabolism and DNA damage/DNA repair are increasingly apparent, yielding opportunities to investigate the mechanistic basis behind potential metabolic vulnerabilities of a substantial fraction of tumors. PMID:29459886

Stem Cells and Gene Therapy for Cartilage Repair

Directory of Open Access Journals (Sweden)

Umile Giuseppe Longo

2012-01-01

Full Text Available Cartilage defects represent a common problem in orthopaedic practice. Predisposing factors include traumas, inflammatory conditions, and biomechanics alterations. Conservative management of cartilage defects often fails, and patients with this lesions may need surgical intervention. Several treatment strategies have been proposed, although only surgery has been proved to be predictably effective. Usually, in focal cartilage defects without a stable fibrocartilaginous repair tissue formed, surgeons try to promote a natural fibrocartilaginous response by using marrow stimulating techniques, such as microfracture, abrasion arthroplasty, and Pridie drilling, with the aim of reducing swelling and pain and improving joint function of the patients. These procedures have demonstrated to be clinically useful and are usually considered as first-line treatment for focal cartilage defects. However, fibrocartilage presents inferior mechanical and biochemical properties compared to normal hyaline articular cartilage, characterized by poor organization, significant amounts of collagen type I, and an increased susceptibility to injury, which ultimately leads to premature osteoarthritis (OA. Therefore, the aim of future therapeutic strategies for articular cartilage regeneration is to obtain a hyaline-like cartilage repair tissue by transplantation of tissues or cells. Further studies are required to clarify the role of gene therapy and mesenchimal stem cells for management of cartilage lesions.

49 CFR 176.54 - Repairs involving welding, burning, and power-actuated tools and appliances.

Science.gov (United States)

2010-10-01

...-actuated tools and appliances. 176.54 Section 176.54 Transportation Other Regulations Relating to..., burning, and power-actuated tools and appliances. (a) Except as provided in paragraph (b) of this section, repairs or work involving welding or burning, or the use of power-actuated tools or appliances which may...

DNA repair pathways involved in determining the level of cytotoxicity of environmentally relevant UV radiation

International Nuclear Information System (INIS)

Carpenter, L.

2000-01-01

The sensitivity of cell lines with defects in various DNA repair processes to different wavelengths of UV has been assessed in order to determine the importance of these repair pathways to the cytotoxicity of UV light. The cell lines used in this work were xrs-6 (a Chinese Hamster Ovary (CHO) cell line) mutant for XRCC5/Ku80, EM9 a CHO cell line mutant for XRCC1, UV61 a CHO cell line mutant for ERCC6/CSB, and E3p53-/-, a mouse embryonic fibroblast cell line null for p53. Xrs-6 (defective in Non Homologous End-Joining) was found to be sensitive to the cytotoxic effects of broadband UVA, but not narrowband UVA or narrowband UVB. EM9 (defective in Base Excision Repair/Single-Strand Break Repair) was not sensitive to the cytotoxic effects of both broadband and narrowband UVA, narrowband UVB or narrowband UVC. UV61 (defective in the Transcription Coupled Repair branch of Nucleotide Excision Repair) was sensitive to the cytotoxic effects of narrowband UVA, UVB and UVC. E3p53-/- was sensitive to the cytotoxic effects of narrowband UVA and UVB. Broadband UVA was found to induce high levels of chromosomal damage in xrs-6, as quantified by the micronucleus assay, most likely as a result of this cell lines inability to repair DNA double strand breaks. EM9 was found to be defective in the repair of broadband UVA-induced single strand breaks, as measured by the alkaline gel electrophoresis ('comet') assay. UV61 was unable to repair broadband UVB-induced DNA damage as measured by the alkaline gel electrophoresis ('comet') assay. These results provide evidence that: 1. DNA double-strand breaks contribute to the cytotoxicity of UVA to a greater extent than single-strand breaks. 2. Repair mechanisms that operate in response to UVA may be coupled to transcription. 3. UVB may directly induce SSBs. 4. P53 is involved in the response of the cell to both UVA and UVB radiation. (author)

Rearrangement of Rag-1 recombinase gene in DNA-repair deficient/immunodeficient wasted'' mice

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Woloschak, G.E.; Weaver, P.; Churchill, M.; Chang-Liu, C-M. (Argonne National Lab., IL (United States)); Libertin, C.R. (Loyola Univ., Maywood, IL (United States))

1992-01-01

Mice recessive for the autosomal gene wasted'' (wst) display a disease pattern which includes increased sensitivity to the killing effects of ionizing radiation, immunodeficiency, and neurologic dysfunction. The recent cloning and characterization of recombinase genes (Rag-l/Rag-2) expressed in lymphoid and possibly central nervous system tissues prompted us to examine expression of these genes in DNA repair-deficient/immunodeficient wasted mice. Our results revealed that in thymus tissue, a small Rag-I transcript (1.0 kb) was detected in wst/wst mice that was not evident in thymus from control mice. In wst/[sm bullet] mice, a two-fold increase in Rag-1 mRNA was evident in thymus tissue. Rag-2 mRNA could only be detected in thymus tissue from wst/[sm bullet] and not from wst/wst or parental control BCF, mice. Southern blots revealed a rearrangement or deletion within the Rag-1 gene of affected wasted mice that was not evident in known strain-specific parental or littermate controls. These results support the idea that the Rag-1 gene may map at or near the locus for the wasted mutation. In addition, they suggest the importance of recombinase function in normal immune and central nervous system development as well as the potential contribution of this gene family to the normal repair of radiation-induced DNA damage.

Specific UV-induced mutation spectrum in the p53 gene of skin tumors from DNA-repair-deficient xeroderma pigmentosum patients

International Nuclear Information System (INIS)

Dumaz, N.; Drougard, C.; Sarasin, A.; Daya-Grosjean, L.

1993-01-01

The UV component of sunlight is the major carcinogen involved in the etiology of skin cancers. The authors have studied the rare, hereditary syndrome xeroderma pigmentosum (XP), which is characterized by a very high incidence of cutaneous tumors on exposed skin at an early age, probably due to a deficiency in excision repair of UV-induced lesions. It is interesting to determine the UV mutation spectrum in XP skin tumors in order to correlate the absence of repair of specific DNA lesions and the initiation of skin tumors. The p53 gene is frequently mutated in human cancers and represents a good target for studying mutation spectra since there are >100 potential sites for phenotypic mutations. Using reverse transcription-PCR and single-strand conformation polymorphism to analyze >40 XP skin tumors (mainly basal and squamous cell carcinomas), the authors have found that 40% (17 out of 43) contained at least one point mutation on the p53 gene. All the mutations were located at dipyrimidine sites, essentially at CC sequences, which are hot spots for UV-induced DNA lesions. Sixty-one percent of these mutations were tandem CC → TT mutations considered to be unique to UV-induced lesions; these mutations are not observed in internal human tumors. All the mutations, except two, must be due to translesion synthesis of unrepaired dipyrimidine lesions left on the nontranscribed strand. These results show the existence of preferential repair of UV lesions [either pyrimidine dimers or pyrimidine-pyrimidone (6-4) photoproducts] on the transcribed strand in human tissues

Genes involved in yeast survival after irradiation with fast neutrons

International Nuclear Information System (INIS)

Bozin, D.; Milosevic, M.J.

2001-01-01

Life on the Earth has evolved against a continuous background of ionizing radiation. It would be expected, therefore, that all possible mutations have been produced at some time or another; man-made radiation from medical or industrial sources will not result in any new types of mutation but will simply increase the whole spectrum of mutations that occur spontaneously. Any such lesion can be mutagenic and, in principle, lethal. To counteract the consequences of DNA damage, evolution has equipped all living cells with an intricate network of defense and repair systems. Together, these systems act as a kind of nuclear 'immune system' that is able to recognize and eliminate many types of DNA lesions. In the case of the yeast Saccharomyces cerevisiae, in these processes over 30 RAD genes participate. We tested the survival of haploid and diploid rad1 yeast mutant strains at a dose of 15 Gy of γ or fast neutron radiation. We demonstrated that the lethality of rad1 mutants both haploid and diploid are significantly higher after fast neutron irradiation. The results indicate to the role and position of these genes in the DNA repair of damages specifically induced by fast neutrons. (authors)

The involvement of human RECQL4 in DNA double-strand break repair

DEFF Research Database (Denmark)

Singh, Dharmendra Kumar; Karmakar, Parimal; Aamann, Maria Diget

2010-01-01

Rothmund-Thomson syndrome (RTS) is an autosomal recessive hereditary disorder associated with mutation in RECQL4 gene, a member of the human RecQ helicases. The disease is characterized by genomic instability, skeletal abnormalities and predisposition to malignant tumors, especially osteosarcomas......-induced DSBs and remains for a shorter duration than WRN and BLM, indicating its distinct role in repair of DSBs. Endogenous RECQL4 also colocalizes with gammaH2AX at the site of DSBs. The RECQL4 domain responsible for its DNA damage localization has been mapped to the unique N-terminus domain between amino...

Attenuated DNA damage repair by trichostatin A through BRCA1 suppression.

Science.gov (United States)

Zhang, Yin; Carr, Theresa; Dimtchev, Alexandre; Zaer, Naghmeh; Dritschilo, Anatoly; Jung, Mira

2007-07-01

Recent studies have demonstrated that some histone deacetylase (HDAC) inhibitors enhance cellular radiation sensitivity. However, the underlying mechanism for such a radiosensitizing effect remains unexplored. Here we show evidence that treatment with the HDAC inhibitor trichostatin A (TSA) impairs radiation-induced repair of DNA damage. The effect of TSA on the kinetics of DNA damage repair was measured by performing the comet assay and gamma-H2AX focus analysis in radioresistant human squamous carcinoma cells (SQ-20B). TSA exposure increased the amount of radiation-induced DNA damage and slowed the repair kinetics. Gene expression profiling also revealed that a majority of the genes that control cell cycle, DNA replication and damage repair processes were down-regulated after TSA exposure, including BRCA1. The involvement of BRCA1 was further demonstrated by expressing ectopic wild-type BRCA1 in a BRCA1 null cell line (HCC-1937). TSA treatment enhanced radiation sensitivity of HCC-1937/wtBRCA1 clonal cells, which restored cellular radiosensitivity (D(0) = 1.63 Gy), to the control level (D(0) = 1.03 Gy). However, TSA had no effect on the level of radiosensitivity of BRCA1 null cells. Our data demonstrate for the first time that TSA treatment modulates the radiation-induced DNA damage repair process, in part by suppressing BRCA1 gene expression, suggesting that BRCA1 is one of molecular targets of TSA.

Genetic Variability in DNA Repair Proteins in Age-Related Macular Degeneration

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Janusz Blasiak

2012-10-01

Full Text Available The pathogenesis of age-related macular degeneration (AMD is complex and involves interactions between environmental and genetic factors, with oxidative stress playing an important role inducing damage in biomolecules, including DNA. Therefore, genetic variability in the components of DNA repair systems may influence the ability of the cell to cope with oxidative stress and in this way contribute to the pathogenesis of AMD. However, few reports have been published on this subject so far. We demonstrated that the c.977C>G polymorphism (rs1052133 in the hOGG1 gene and the c.972G>C polymorphism (rs3219489 in the MUTYH gene, the products of which play important roles in the repair of oxidatively damaged DNA, might be associated with the risk of AMD. Oxidative stress may promote misincorporation of uracil into DNA, where it is targeted by several DNA glycosylases. We observed that the g.4235T>C (rs2337395 and c.−32A>G (rs3087404 polymorphisms in two genes encoding such glycosylases, UNG and SMUG1, respectively, could be associated with the occurrence of AMD. Polymorphisms in some other DNA repair genes, including XPD (ERCC2, XRCC1 and ERCC6 (CSB have also been reported to be associated with AMD. These data confirm the importance of the cellular reaction to DNA damage, and this may be influenced by variability in DNA repair genes, in AMD pathogenesis.

The studies of DNA double-strand break (DSB) rejoining and mRNA expression of repair gene XRCCs in malignant transformed cell lines of human bronchial epithelial cells generated by α-particles

International Nuclear Information System (INIS)

Sun Jingfen; Sui Jianli; Geng Yu; Zhou Pingkun; Wu Dechang

2002-01-01

Objective: To investigate the efficiency of γ-ray-induced DNA DSB rejoining and the mRNA expression of DNA repair genes in malignantly transformed cell lines of human bronchial epithelial cells generated by exposure to a-particles. Methods: Pulsed field gel electrophoresis (PFGE) was used to detect DNA. DSBs mRNA expression was analyzed by RT-PCR. Results: The residual DNA DSB damage level after 4hrs repair following 0-150 Gy of γ-irradiation in the malignantly transformed cell lines BERP35T-1 and BERP35T-4 was significantly higher than that in their parental BEP2D cells. The analysis of mRNA level revealed a 2.5-to 6.5-fold down-regulated expression of the DNA repair genes XRCC-2, XRCC-3 and Ku80 (XRCC-5) in BERP35T-1 and BERP35T-4 cells as compared with the parental BEP2D cells. In contrast, the expression of DNA-PKcs(XRCC7) was 2.4-fold up-regulated in the transformed cell line BERP35T-4, in which there was a significantly higher proportion of polyploid cells. Conclusion: This study results show that the deficiency of DNA DSB rejoining and depressed mRNA expression of DNA repair genes could be involved in the malignant transformation process of BEP2D cells induced by exposure to α-particles

Postreplication repair gap filling in an Escherichia coli strain deficient in dnaB gene product

International Nuclear Information System (INIS)

Johnson, R.C.

1975-01-01

Gaps in daughter-strand DNA synthesized after exposure of Escherichia coli E279 to ultraviolet light are filled during reincubation at 30 0 C for 20 min. Escherichia coli E279 is phenotypically DnaB - when incubated at 43 0 C. Cells incubated at 43 0 C were tested for their ability to complete postreplication repair gap filling. It is concluded that the dnaB gene product is essential for postreplication repair gap filling and that the inhibition seen is not initially the result of degradation

Intraoperative optical coherence tomography in macula involving rhegmatogenous retinal detachment repair with pars plana vitrectomy and perfluoron.

Science.gov (United States)

Toygar, O; Riemann, C D

2016-01-01

PurposeTo investigate microanatomical relationships during surgical repair of macula involving retinal detachment with pars plana vitrectomy (PPV) and perfluoron (PFO) with a microscope-integrated intraoperative optical coherence tomography (iOCT) device.Patients and methodsThis consecutive case series included nine eyes of nine patients with macula involving retinal detachment operated by a single surgeon at the Cincinnati Eye Institute. All patients underwent PPV, PFO injection, endolaser, and air-fluid exchange. The macula was imaged with iOCT before PFO injection, after PFO injection, and after air-fluid exchange in all eyes.ResultsiOCT imaging was ergonomically easy to obtain in all eyes. iOCT clearly demonstrated submacular fluid (SMF) at the beginning of the surgery, macular flattening under PFO in all eyes, small residual SMF under PFO in six of nine eyes, and increased occult SMF following air-fluid exchange in all eyes.ConclusionMicroscope-integrated iOCT is a versatile and powerful imaging modality that holds a great deal of promise in the future. Its confirmation of persistent occult SMF in this small series of macular involving retinal detachment repair with PFO, may inform surgical decision making, and demonstrates a pathophysiological rationale for initial face-down positioning after retinal detachment repair.

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 (pcurcumin and irradiation compared with irradiation alone (pcurcumin and irradiation resulted in a significantly greater tumor-growth inhibition and apoptosis compared to irradiation treatment alone (pCurcumin 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.

Stripped-down DNA repair in a highly reduced parasite

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Fast Naomi M

2007-03-01

Full Text Available Abstract Background Encephalitozoon cuniculi is a member of a distinctive group of single-celled parasitic eukaryotes called microsporidia, which are closely related to fungi. Some of these organisms, including E. cuniculi, also have uniquely small genomes that are within the prokaryotic range. Thus, E. cuniculi has undergone a massive genome reduction which has resulted in a loss of genes from diverse biological pathways, including those that act in DNA repair. DNA repair is essential to any living cell. A loss of these mechanisms invariably results in accumulation of mutations and/or cell death. Six major pathways of DNA repair in eukaryotes include: non-homologous end joining (NHEJ, homologous recombination repair (HRR, mismatch repair (MMR, nucleotide excision repair (NER, base excision repair (BER and methyltransferase repair. DNA polymerases are also critical players in DNA repair processes. Given the close relationship between microsporidia and fungi, the repair mechanisms present in E. cuniculi were compared to those of the yeast Saccharomyces cerevisiae to ascertain how the process of genome reduction has affected the DNA repair pathways. Results E. cuniculi lacks 16 (plus another 6 potential absences of the 56 DNA repair genes sought via BLASTP and PSI-BLAST searches. Six of 14 DNA polymerases or polymerase subunits are also absent in E. cuniculi. All of these genes are relatively well conserved within eukaryotes. The absence of genes is not distributed equally among the different repair pathways; some pathways lack only one protein, while there is a striking absence of many proteins that are components of both double strand break repair pathways. All specialized repair polymerases are also absent. Conclusion Given the large number of DNA repair genes that are absent from the double strand break repair pathways, E. cuniculi is a prime candidate for the study of double strand break repair with minimal machinery. Strikingly, all of the

Participation of different genes in the ruptures repair of double chain in Escherichia coli stumps exposed to gamma radiation

International Nuclear Information System (INIS)

Serment G, J. H.; Martinez M, E.; Alcantara D, D.

2013-01-01

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)

Repair of full-thickness articular cartilage defects by cultured mesenchymal stem cells transfected with the transforming growth factor β1 gene

International Nuclear Information System (INIS)

Guo Xiaodong; Zheng Qixin; Yang Shuhua; Shao Zengwu; Yuan Quan; Pan Zhengqi; Tang Shuo; Liu Kai; Quan Daping

2006-01-01

Articular cartilage repair remains a clinical and scientific challenge with increasing interest focused on the combined techniques of gene transfer and tissue engineering. Transforming growth factor beta 1 (TGF-β 1 ) is a multifunctional molecule that plays a central role in promotion of cartilage repair, and inhibition of inflammatory and alloreactive immune response. Cell mediated gene therapy can allow a sustained expression of TGF-β 1 that may circumvent difficulties associated with growth factor delivery. The objective of this study was to investigate whether TGF-β 1 gene modified mesenchymal stem cells (MSCs) could enhance the repair of full-thickness articular cartilage defects in allogeneic rabbits. The pcDNA 3 -TGF-β 1 gene transfected MSCs were seeded onto biodegradable poly-L-lysine coated polylactide (PLA) biomimetic scaffolds in vitro and allografted into full-thickness articular cartilage defects in 18 New Zealand rabbits. The pcDNA 3 gene transfected MSCs/biomimetic scaffold composites and the cell-free scaffolds were taken as control groups I and II, respectively. The follow-up times were 2, 4, 12 and 24 weeks. Macroscopical, histological and ultrastructural studies were performed. In vitro SEM studies found that abundant cartilaginous matrices were generated and completely covered the interconnected pores of the scaffolds two weeks post-seeding in the experimental groups. In vivo, the quality of regenerated tissue improved over time with hyaline cartilage filling the chondral region and a mixture of trabecular and compact bone filling the subchondral region at 24 weeks post-implantation. Joint repair in the experimental groups was better than that of either control group I or II, with respect to: (1) synthesis of hyaline cartilage specific extracellular matrix at the upper portion of the defect; (2) reconstitution of the subchondral bone at the lower portion of the defect and (3) inhibition of inflammatory and alloreactive immune responses. The

The relation between repair of DNA and radiation and chemical mutagenesis in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Prakash, L.

1976-01-01

The effect of various genes involved in DNA repair functions on radiation and chemical mutagenesis in Escherichia coli is discussed and compared to similar studies done in yeast. Results of the effect of various genes conferring radiation-sensitivty on mutation induction in yeast are presented and related to current ideas of mutagenesis

DnaB gene product-independence of DNA polymerase III-directed repair synthesis in Escherichia coli K-12

International Nuclear Information System (INIS)

Billen, D.; Hellermann, G.R.

1977-01-01

An investigation has been carried out into the role of dnaB gene product in X-ray-induced repair synthesis carried out by DNA polymerase III in toluene-treated Escherichia coli K-12. A polAl polBlOO dnaB mutant deficient in both DNA polymerase I and II activities was used, and it was shown that the level of X-ray-induced, ATP-dependent, non-conservative DNA synthesis was, unlike semi-conservative DNA synthesis, unaffected by a temperature shift from 30 0 to 42 0 C. The dnaB gene product was not therefore necessary for DNA polymerase III-directed repair synthesis, which occurred in the absence of replicative synthesis. (U.K.)

Nucleotide excision repair- and p53-deficient mouse models in cancer research

Energy Technology Data Exchange (ETDEWEB)

Hoogervorst, Esther M. [Laboratory of Toxicology, Pathology and Genetics, National Institute of Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven (Netherlands); Utrecht University, Department of Pathobiology, Utrecht (Netherlands); Steeg, Harry van [Laboratory of Toxicology, Pathology and Genetics, National Institute of Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven (Netherlands); Vries, Annemieke de [Laboratory of Toxicology, Pathology and Genetics, National Institute of Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven (Netherlands)]. E-mail: Annemieke.de.Vries@rivm.nl

2005-07-01

Cancer is caused by the loss of controlled cell growth due to mutational (in)activation of critical genes known to be involved in cell cycle regulation. Three main mechanisms are known to be involved in the prevention of cells from becoming cancerous; DNA repair and cell cycle control, important to remove DNA damage before it will be fixed into mutations and apoptosis, resulting in the elimination of cells containing severe DNA damage. Several human syndromes are known to have (partially) deficiencies in these pathways, and are therefore highly cancer prone. Examples are xeroderma pigmentosum (XP) caused by an inborn defect in the nucleotide excision repair (NER) pathway and the Li-Fraumeni syndrome, which is the result of a germ line mutation in the p53 gene. XP patients develop skin cancer on sun exposed areas at a relatively early age, whereas Li-Fraumeni patients spontaneously develop a wide variety of early onset tumors, including sarcomas, leukemia's and mammary gland carcinomas. Several mouse models have been generated to mimic these human syndromes, providing us information about the role of these particular gene defects in the tumorigenesis process. In this review, spontaneous phenotypes of mice deficient for nucleotide excision repair and/or the p53 gene will be described, together with their responses upon exposure to either chemical carcinogens or radiation. Furthermore, possible applications of these and newly generated mouse models for cancer will be given.

Polymorphisms in RAI and in genes of nucleotide and base excision repair are not associated with risk of testicular cancer.

Science.gov (United States)

Laska, Magdalena J; Nexø, Bjørn A; Vistisen, Kirsten; Poulsen, Henrik Enghusen; Loft, Steffen; Vogel, Ulla

2005-07-28

Testicular cancer has been suggested to be primed in utero and there is familiar occurrence, particularly brothers and sons of men with testicular cancer have increased risk. Although no specific causative genotoxic agents have been identified, variations in DNA repair capacity could be associated with the risk of testicular cancer. A case-control study of 184 testicular cancer cases and 194 population-based controls living in the Copenhagen Greater Area in Denmark was performed. We found that neither polymorphisms in several DNA repair genes nor alleles of several polymorphisms in the chromosomal of region 19q13.2-3, encompassing the genes ASE, ERCC1, RAI and XPD, were associated with risk of testicular cancer in Danish patients. This is in contrast to other cancers, where we reported strong associations between polymorphisms in ERCC1, ASE and RAI and occurrence of basal cell carcinoma, breast cancer and lung. To our knowledge this is the first study of DNA repair gene polymorphisms and risk of testicular cancer.

Influence of XRCC1 Genetic Polymorphisms on Ionizing Radiation-Induced DNA Damage and Repair

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Silvia Sterpone

2010-01-01

Full Text Available It is well known that ionizing radiation (IR can damage DNA through a direct action, producing single- and double-strand breaks on DNA double helix, as well as an indirect effect by generating oxygen reactive species in the cells. Mammals have evolved several and distinct DNA repair pathways in order to maintain genomic stability and avoid tumour cell transformation. This review reports important data showing a huge interindividual variability on sensitivity to IR and in susceptibility to developing cancer; this variability is principally represented by genetic polymorphisms, that is, DNA repair gene polymorphisms. In particular we have focussed on single nucleotide polymorphisms (SNPs of XRCC1, a gene that encodes for a scaffold protein involved basically in Base Excision Repair (BER. In this paper we have reported and presented recent studies that show an influence of XRCC1 variants on DNA repair capacity and susceptibility to breast cancer.

Influence of XRCC1 Genetic Polymorphisms on Ionizing Radiation-Induced DNA Damage and Repair.

Science.gov (United States)

Sterpone, Silvia; Cozzi, Renata

2010-07-25

It is well known that ionizing radiation (IR) can damage DNA through a direct action, producing single- and double-strand breaks on DNA double helix, as well as an indirect effect by generating oxygen reactive species in the cells. Mammals have evolved several and distinct DNA repair pathways in order to maintain genomic stability and avoid tumour cell transformation. This review reports important data showing a huge interindividual variability on sensitivity to IR and in susceptibility to developing cancer; this variability is principally represented by genetic polymorphisms, that is, DNA repair gene polymorphisms. In particular we have focussed on single nucleotide polymorphisms (SNPs) of XRCC1, a gene that encodes for a scaffold protein involved basically in Base Excision Repair (BER). In this paper we have reported and presented recent studies that show an influence of XRCC1 variants on DNA repair capacity and susceptibility to breast cancer.

Introduction of the yeast DNA repair gene PHR1 into normal and xeroderma pigmentosum human cells

International Nuclear Information System (INIS)

Whyte, D.B.

1988-01-01

The goal of the work described herein is to determine how UV light kills and mutates human cells. Specifically, the hypothesis to be tested states that the major cause of cell death is the cyclobutane dimer. The yeast (S. cerevisiae) enzyme photolyase provides an elegant means of dissecting the biological effects of the two lesions. Photolyase, the product of the PHR1 gene, catalyzes the visible light-dependent reversal of cyclobutane pyrimidine dimers. Introducing the gene for photolyase into human cells, which do not have a functional photoreactivation mechanism, should allow specific repair of cyclobutane pyrimidine dimers. To express the yeast DNA repair gene in human cells, the yeast PHR1 coding sequence was cloned into the mammalian expression vector pRSV4NEO-I. The resulting plasmid, pRSVPHR1, contains the coding sequence of the yeast gene, under control of transcription signals recognized by mammalian cells, and the dominant selectable gene neo. pRSVPHR1 was introduced into normal and XP SV40-transformed fibroblasts by the calcium phosphate coprecipitation technique, and G418-resistant clones were isolated. The level of PHR1 expression was determined by cytoplasmic RNA dot blots. Two clones, XP-3B and GM-20A, had high levels of expression

Polymorphisms of LIG4, BTBD2, HMGA2, and RTEL1 genes involved in the double-strand break repair pathway predict glioblastoma survival.

Science.gov (United States)

Liu, Yanhong; Shete, Sanjay; Etzel, Carol J; Scheurer, Michael; Alexiou, George; Armstrong, Georgina; Tsavachidis, Spyros; Liang, Fu-Wen; Gilbert, Mark; Aldape, Ken; Armstrong, Terri; Houlston, Richard; Hosking, Fay; Robertson, Lindsay; Xiao, Yuanyuan; Wiencke, John; Wrensch, Margaret; Andersson, Ulrika; Melin, Beatrice S; Bondy, Melissa

2010-05-10

Glioblastoma (GBM) is the most common and aggressive type of glioma and has the poorest survival. However, a small percentage of patients with GBM survive well beyond the established median. Therefore, identifying the genetic variants that influence this small number of unusually long-term survivors may provide important insight into tumor biology and treatment. Among 590 patients with primary GBM, we evaluated associations of survival with the 100 top-ranking glioma susceptibility single nucleotide polymorphisms from our previous genome-wide association study using Cox regression models. We also compared differences in genetic variation between short-term survivors (STS; or= 36 months), and explored classification and regression tree analysis for survival data. We tested results using two independent series totaling 543 GBMs. We identified LIG4 rs7325927 and BTBD2 rs11670188 as predictors of STS in GBM and CCDC26 rs10464870 and rs891835, HMGA2 rs1563834, and RTEL1 rs2297440 as predictors of LTS. Further survival tree analysis revealed that patients >or= 50 years old with LIG4 rs7325927 (V) had the worst survival (median survival time, 1.2 years) and exhibited the highest risk of death (hazard ratio, 17.53; 95% CI, 4.27 to 71.97) compared with younger patients with combined RTEL1 rs2297440 (V) and HMGA2 rs1563834 (V) genotypes (median survival time, 7.8 years). Polymorphisms in the LIG4, BTBD2, HMGA2, and RTEL1 genes, which are involved in the double-strand break repair pathway, are associated with GBM survival.

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...

DNA repair mechanisms in cancer development and therapy.

Science.gov (United States)

Torgovnick, Alessandro; Schumacher, Björn

2015-01-01

DNA damage has been long recognized as causal factor for cancer development. When erroneous DNA repair leads to mutations or chromosomal aberrations affecting oncogenes and tumor suppressor genes, cells undergo malignant transformation resulting in cancerous growth. Genetic defects can predispose to cancer: mutations in distinct DNA repair systems elevate the susceptibility to various cancer types. However, DNA damage not only comprises a root cause for cancer development but also continues to provide an important avenue for chemo- and radiotherapy. Since the beginning of cancer therapy, genotoxic agents that trigger DNA damage checkpoints have been applied to halt the growth and trigger the apoptotic demise of cancer cells. We provide an overview about the involvement of DNA repair systems in cancer prevention and the classes of genotoxins that are commonly used for the treatment of cancer. A better understanding of the roles and interactions of the highly complex DNA repair machineries will lead to important improvements in cancer therapy.

DNA Repair Mechanisms in Cancer Development and Therapy

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Alessandro eTorgovnick

2015-04-01

Full Text Available DNA damage has been long recognized as causal factor for cancer development. When erroneous DNA repair leads to mutations or chromosomal aberrations affecting oncogenes and tumor suppressor genes, cells undergo malignant transformation resulting in cancerous growth. Genetic defects can predispose to cancer: Mutations in distinct DNA repair systems elevate the susceptibility to various cancer types. However, DNA damage not only comprises a root cause for cancer development but also continues to provide an important avenue for chemo- and radiotherapy. Since the beginning of cancer therapy, genotoxic agents have been applied that trigger DNA damage checkpoints that halt the growth and trigger the apoptotic demise of cancer cells. We provide an overview about the involvement of DNA repair systems in cancer prevention and the classes of genotoxins that are commonly used for the treatment of cancer. A better understanding of the roles and interactions of the highly complex DNA repair machineries will lead to important improvements in cancer therapy.

Exploring genes and pathways involved in migraine

NARCIS (Netherlands)

Eising, E.

2017-01-01

The research in this thesis was aimed at identifying genes and molecular pathways involved in migraine. To this end, two gene expression analyses were performed in brain tissue obtained from transgenic mouse models for familial hemiplegic migraine (FHM), a monogenic subtype of migraine with aura.

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...... Lynch syndrome families. These mutations affected MLH1 in 40%, MSH2 in 36%, MSH6 in 18% and PMS2 in 6% of the families. A large variety of mutations were identified with splice site mutations being the most common mutation type in MLH1 and frameshift mutations predominating in MSH2 and MSH6. Large...... deletions of one or several exons accounted for 21% of the mutations in MLH1 and MSH2 and 22% in PMS2, but were rare (4%) in MSH6. In 66% of the Lynch syndrome families the variants identified were private and the effect from founder mutations was limited and predominantly related to a Finnish founder...

Identification of human genes involved in cellular responses to ionizing radiation: molecular and cellular studies of gene encoding the p68 helicase in mammalian cells

International Nuclear Information System (INIS)

Menaa, F.

2003-12-01

Cells submitted to genotoxic factors -like IR- activate several and important mechanisms such as repair, cell cycle arrest or 'apoptosis' to maintain genetic integrity. So, the damaged cells will induce many and different genes. The human transcriptome analysis by 'SSH' method in a human breast carcinoma cell line MCF7 γ-irradiated versus not irradiated, allowed to identify about one hundred genes. Among of these genes, we have focused our study on a radio-induced gene encoding the p68 helicase. In the conditions of irradiation used, our results show that the kinetic and the regulation of this gene expression differs between the nature of radiations used. Indeed, in γ-irradiated mammalian cells, ATM, a protein kinase activated by DSB and IR, is required to induce quickly P68 gene via the important transcription factor p53 stabilized by IR. In the case of UVC-irradiated cells, the P68 gene induction is late and the intracellular signalling pathway that lead to this induction is independent from the p53 protein. Finally, we show that the p68 protein under-expression is responsible for an increased radiosensitivity of MCF7 cells. Consequently, we can postulate that the p68 protein is involved in cellular responses to radiations to reduce the increased radiosensitivity of cells exposed to γ-rays. (author)

DNA repair and radiation sensitivity in mammalian cells

International Nuclear Information System (INIS)

Chen, D.J.C.; Stackhouse, M.; Chen, D.S.

1993-01-01

Ionizing radiation induces various types of damage in mammalian cells including DNA single-strand breaks, DNA double-strand breaks (DSB), DNA-protein cross links, and altered DNA bases. Although human cells can repair many of these lesions there is little detailed knowledge of the nature of the genes and the encoded enzymes that control these repair processes. We report here on the cellular and genetic analyses of DNA double-strand break repair deficient mammalian cells. It has been well established that the DNA double-strand break is one of the major lesions induced by ionizing radiation. Utilizing rodent repair-deficient mutant, we have shown that the genes responsible for DNA double-strand break repair are also responsible for the cellular expression of radiation sensitivity. The molecular genetic analysis of DSB repair in rodent/human hybrid cells indicate that at least 6 different genes in mammalian cells are responsible for the repair of radiation-induced DNA double-strand breaks. Mapping and the prospect of cloning of human radiation repair genes are reviewed. Understanding the molecular and genetic basis of radiation sensitivity and DNA repair in man will provide a rational foundation to predict the individual risk associated with radiation exposure and to prevent radiation-induced genetic damage in the human population

Host genes involved in Agrobacterium-mediated transformation

NARCIS (Netherlands)

Soltani, Jalal

2009-01-01

Agrobacterium is the nature’s genetic engineer that can transfer genes across the kingdom barriers to both prokaryotic and eukaryotic host cells. The host genes which are involved in Agrobacterium-mediated transformatiom (AMT) are not well known. Here, I studied in a systematic way to identify the

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

International Nuclear Information System (INIS)

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

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. The authors 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. They 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. 37 refs., 4 figs

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

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...

Sos - response induction by gamma radiation in Escherichia coli strains with different repair capacities

International Nuclear Information System (INIS)

Serment Guerrero, J.H.

1992-01-01

The Sos - response in Escherichia coli is formed by several genes involved in mechanisms of tolerance and/or repair, and only activates when a DNA - damage appears. It is controlled by recA and lexA genes. In normal circumstances, LexA protein is linked in every Sos operators, blocking the transcription. When a DNA damage occurs, a Sos signal is generated, Rec A protein changes its normal functions, starts acting as a protease and cleaves Lex A, allowing the transcription of all Sos genes. This response can be quantified by means of Sos Chromo test, performed by Quillardet and Ofnung (1985). In using the Chromo test, it has been observed that the DNA damage made by gamma radiation in Escherichia coli depends on both the doses and the doses rate. It has been shown that the exposure of Escherichia coli PQ37 strain (uvrA) to low doses at low dose rate appears to retard the response, suggesting the action of a repair mechanism. (Brena 1990). In this work, we compare the response in Escherichia coli strains deficient in different mechanisms of repair and/or tolerance. It is observed the importance of rec N gene in the repair of DNA damage produced by gamma radiation. (Author)

Repair of full-thickness articular cartilage defects by cultured mesenchymal stem cells transfected with the transforming growth factor {beta}{sub 1} gene

Energy Technology Data Exchange (ETDEWEB)

Guo Xiaodong [Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Zheng Qixin [Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Yang Shuhua [Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Shao Zengwu [Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Yuan Quan [Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Pan Zhengqi [Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Tang Shuo [Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Liu Kai [Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Quan Daping [Institute of Polymer Science, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275 (China)

2006-12-15

Articular cartilage repair remains a clinical and scientific challenge with increasing interest focused on the combined techniques of gene transfer and tissue engineering. Transforming growth factor beta 1 (TGF-{beta}{sub 1}) is a multifunctional molecule that plays a central role in promotion of cartilage repair, and inhibition of inflammatory and alloreactive immune response. Cell mediated gene therapy can allow a sustained expression of TGF-{beta}{sub 1} that may circumvent difficulties associated with growth factor delivery. The objective of this study was to investigate whether TGF-{beta}{sub 1} gene modified mesenchymal stem cells (MSCs) could enhance the repair of full-thickness articular cartilage defects in allogeneic rabbits. The pcDNA{sub 3}-TGF-{beta}{sub 1} gene transfected MSCs were seeded onto biodegradable poly-L-lysine coated polylactide (PLA) biomimetic scaffolds in vitro and allografted into full-thickness articular cartilage defects in 18 New Zealand rabbits. The pcDNA{sub 3} gene transfected MSCs/biomimetic scaffold composites and the cell-free scaffolds were taken as control groups I and II, respectively. The follow-up times were 2, 4, 12 and 24 weeks. Macroscopical, histological and ultrastructural studies were performed. In vitro SEM studies found that abundant cartilaginous matrices were generated and completely covered the interconnected pores of the scaffolds two weeks post-seeding in the experimental groups. In vivo, the quality of regenerated tissue improved over time with hyaline cartilage filling the chondral region and a mixture of trabecular and compact bone filling the subchondral region at 24 weeks post-implantation. Joint repair in the experimental groups was better than that of either control group I or II, with respect to: (1) synthesis of hyaline cartilage specific extracellular matrix at the upper portion of the defect; (2) reconstitution of the subchondral bone at the lower portion of the defect and (3) inhibition of

Tissue repair genes: the TiRe database and its implication for skin wound healing.

Science.gov (United States)

Yanai, Hagai; Budovsky, Arie; Tacutu, Robi; Barzilay, Thomer; Abramovich, Amir; Ziesche, Rolf; Fraifeld, Vadim E

2016-04-19

Wound healing is an inherent feature of any multicellular organism and recent years have brought about a huge amount of data regarding regular and abnormal tissue repair. Despite the accumulated knowledge, modulation of wound healing is still a major biomedical challenge, especially in advanced ages. In order to collect and systematically organize what we know about the key players in wound healing, we created the TiRe (Tissue Repair) database, an online collection of genes and proteins that were shown to directly affect skin wound healing. To date, TiRe contains 397 entries for four organisms: Mus musculus, Rattus norvegicus, Sus domesticus, and Homo sapiens. Analysis of the TiRe dataset of skin wound healing-associated genes showed that skin wound healing genes are (i) over-conserved among vertebrates, but are under-conserved in invertebrates; (ii) enriched in extracellular and immuno-inflammatory genes; and display (iii) high interconnectivity and connectivity to other proteins. The latter may provide potential therapeutic targets. In addition, a slower or faster skin wound healing is indicative of an aging or longevity phenotype only when assessed in advanced ages, but not in the young. In the long run, we aim for TiRe to be a one-station resource that provides researchers and clinicians with the essential data needed for a better understanding of the mechanisms of wound healing, designing new experiments, and the development of new therapeutic strategies. TiRe is freely available online at http://www.tiredb.org.

Human Fanconi anemia monoubiquitination pathway promotes homologous DNA repair.

Science.gov (United States)

Nakanishi, Koji; Yang, Yun-Gui; Pierce, Andrew J; Taniguchi, Toshiyasu; Digweed, Martin; D'Andrea, Alan D; Wang, Zhao-Qi; Jasin, Maria

2005-01-25

Fanconi anemia (FA) is a recessive disorder characterized by congenital abnormalities, progressive bone-marrow failure, and cancer susceptibility. Cells from FA patients are hypersensitive to agents that produce DNA crosslinks and, after treatment with these agents, have pronounced chromosome breakage and other cytogenetic abnormalities. Eight FANC genes have been cloned, and the encoded proteins interact in a common cellular pathway. DNA-damaging agents activate the monoubiquitination of FANCD2, resulting in its targeting to nuclear foci that also contain BRCA1 and BRCA2/FANCD1, proteins involved in homology-directed DNA repair. Given the interaction of the FANC proteins with BRCA1 and BRCA2, we tested whether cells from FA patients (groups A, G, and D2) and mouse Fanca-/- cells with a targeted mutation are impaired for this repair pathway. We find that both the upstream (FANCA and FANCG) and downstream (FANCD2) FA pathway components promote homology-directed repair of chromosomal double-strand breaks (DSBs). The FANCD2 monoubiquitination site is critical for normal levels of repair, whereas the ATM phosphorylation site is not. The defect in these cells, however, is mild, differentiating them from BRCA1 and BRCA2 mutant cells. Surprisingly, we provide evidence that these proteins, like BRCA1 but unlike BRCA2, promote a second DSB repair pathway involving homology, i.e., single-strand annealing. These results suggest an early role for the FANC proteins in homologous DSB repair pathway choice.

Co-expression of antioxidant enzymes with expression of p53, DNA repair, and heat shock protein genes in the gamma ray-irradiated hermaphroditic fish Kryptolebias marmoratus larvae

Energy Technology Data Exchange (ETDEWEB)

Rhee, Jae-Sung [Research Institute for Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, Bo-Mi; Kim, Ryeo-Ok [Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Seo, Jung Soo [Pathology Team, National Fisheries Research and Development Institute, Busan 619-902 (Korea, Republic of); Kim, Il-Chan [Division of Life Sciences, Korea Polar Research Institute, Korea Institute of Ocean Science and Technology, Incheon 406-840 (Korea, Republic of); Lee, Young-Mi, E-mail: ymlee70@smu.ac.kr [Department of Green Life Science, College of Convergence, Sangmyung University, Seoul 110-743 (Korea, Republic of); Lee, Jae-Seong, E-mail: jslee2@hanyang.ac.kr [Research Institute for Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Chemistry, College of Natural Sciences, Hanyang University, Seoul 133-791 (Korea, Republic of)

2013-09-15

Highlights: •Novel identification of DNA repair-related genes in fish. •Investigation of whole expression profiling of DNA repair genes upon gamma radiation. •Analysis of effects of gamma radiation on antioxidant system and cell stress proteins. •Usefulness of verification of pathway-based profiling for mechanistic understanding. -- Abstract: To investigate effects of gamma ray irradiation in the hermaphroditic fish, Kryptolebias marmoratus larvae, we checked expression of p53, DNA repair, and heat shock protein genes with several antioxidant enzyme activities by quantitative real-time RT-PCR and biochemical methods in response to different doses of gamma radiation. As a result, the level of gamma radiation-induced DNA damage was initiated after 4 Gy of radiation, and biochemical and molecular damage became substantial from 8 Gy. In particular, several DNA repair mechanism-related genes were significantly modulated in the 6 Gy gamma radiation-exposed fish larvae, suggesting that upregulation of such DNA repair genes was closely associated with cell survival after gamma irradiation. The mRNA expression of p53 and most hsps was also significantly upregulated at high doses of gamma radiation related to cellular damage. This finding indicates that gamma radiation can induce oxidative stress with associated antioxidant enzyme activities, and linked to modulation of the expression of DNA repair-related genes as one of the defense mechanisms against radiation damage. This study provides a better understanding of the molecular mode of action of defense mechanisms upon gamma radiation in fish larvae.

Mutation update for the CSB/ERCC6 and CSA/ERCC8 genes involved in Cockayne syndrome.

Science.gov (United States)

Laugel, V; Dalloz, C; Durand, M; Sauvanaud, F; Kristensen, U; Vincent, M C; Pasquier, L; Odent, S; Cormier-Daire, V; Gener, B; Tobias, E S; Tolmie, J L; Martin-Coignard, D; Drouin-Garraud, V; Heron, D; Journel, H; Raffo, E; Vigneron, J; Lyonnet, S; Murday, V; Gubser-Mercati, D; Funalot, B; Brueton, L; Sanchez Del Pozo, J; Muñoz, E; Gennery, A R; Salih, M; Noruzinia, M; Prescott, K; Ramos, L; Stark, Z; Fieggen, K; Chabrol, B; Sarda, P; Edery, P; Bloch-Zupan, A; Fawcett, H; Pham, D; Egly, J M; Lehmann, A R; Sarasin, A; Dollfus, H

2010-02-01

Cockayne syndrome is an autosomal recessive multisystem disorder characterized principally by neurological and sensory impairment, cachectic dwarfism, and photosensitivity. This rare disease is linked to mutations in the CSB/ERCC6 and CSA/ERCC8 genes encoding proteins involved in the transcription-coupled DNA repair pathway. The clinical spectrum of Cockayne syndrome encompasses a wide range of severity from severe prenatal forms to mild and late-onset presentations. We have reviewed the 45 published mutations in CSA and CSB to date and we report 43 new mutations in these genes together with the corresponding clinical data. Among the 84 reported kindreds, 52 (62%) have mutations in the CSB gene. Many types of mutations are scattered along the whole coding sequence of both genes, but clusters of missense mutations can be recognized and highlight the role of particular motifs in the proteins. Genotype-phenotype correlation hypotheses are considered with regard to these new molecular and clinical data. Additional cases of molecular prenatal diagnosis are reported and the strategy for prenatal testing is discussed. Two web-based locus-specific databases have been created to list all identified variants and to allow the inclusion of future reports (www.umd.be/CSA/ and www.umd.be/CSB/). (c) 2009 Wiley-Liss, Inc.

Bioactive Dietary VDR Ligands Regulate Genes Encoding Biomarkers of Skin Repair That Are Associated with Risk for Psoriasis

Directory of Open Access Journals (Sweden)

Amitis Karrys

2018-02-01

Full Text Available Treatment with 1,25-dihydroxyvitamin D3 (1,25D improves psoriasis symptoms, possibly by inducing the expression of late cornified envelope (LCE3 genes involved in skin repair. In psoriasis patients, the majority of whom harbor genomic deletion of LCE3B and LCE3C (LCE3C_LCE3B-del, we propose that certain dietary analogues of 1,25D activate the expression of residual LCE3A/LCE3D/LCE3E genes to compensate for the loss of LCE3B/LCE3C in the deletant genotype. Herein, human keratinocytes (HEKn homozygous for LCE3C_LCE3B-del were treated with docosahexaenoic acid (DHA and curcumin, two low-affinity, nutrient ligands for the vitamin D receptor (VDR. DHA and curcumin induce the expression of LCE3A/LCE3D/LCE3E mRNAs at concentrations corresponding to their affinity for VDR. Moreover, immunohistochemical quantitation revealed that the treatment of keratinocytes with DHA or curcumin stimulates LCE3 protein expression, while simultaneously opposing the tumor necrosis factor-alpha (TNFα-signaled phosphorylation of mitogen activated protein (MAP kinases, p38 and Jun amino-terminal kinase (JNK, thereby overcoming inflammation biomarkers elicited by TNFα challenge. Finally, DHA and curcumin modulate two transcription factors relevant to psoriatic inflammation, the activator protein-1 factor Jun B and the nuclear receptor NR4A2/NURR1, that is implicated as a mediator of VDR ligand-triggered gene control. These findings provide insights into the mechanism(s whereby dietary VDR ligands alter inflammatory and barrier functions relevant to skin repair, and may provide a molecular basis for improved treatments for mild/moderate psoriasis.

Microsatellites in the Eukaryotic DNA Mismatch Repair Genes as Modulators of Evolutionary Mutation Rate

Science.gov (United States)

Chang, Dong Kyung; Metzgar, David; Wills, Christopher; Boland, C. Richard

2003-01-01

All "minor" components of the human DNA mismatch repair (MMR) system-MSH3, MSH6, PMS2, and the recently discovered MLH3-contain mononucleotide microsatellites in their coding sequences. This intriguing finding contrasts with the situation found in the major components of the DNA MMR system-MSH2 and MLH1-and, in fact, most human genes. Although eukaryotic genomes are rich in microsatellites, non-triplet microsatellites are rare in coding regions. The recurring presence of exonal mononucleotide repeat sequences within a single family of human genes would therefore be considered exceptional.

TaMSH7: A cereal mismatch repair gene that affects fertility in transgenic barley (Hordeum vulgare L.

Directory of Open Access Journals (Sweden)

Langridge Peter

2007-12-01

Full Text Available Abstract Background Chromosome pairing, recombination and DNA repair are essential processes during meiosis in sexually reproducing organisms. Investigating the bread wheat (Triticum aestivum L. Ph2 (Pairing homoeologous locus has identified numerous candidate genes that may have a role in controlling such processes, including TaMSH7, a plant specific member of the DNA mismatch repair family. Results Sequencing of the three MSH7 genes, located on the short arms of wheat chromosomes 3A, 3B and 3D, has revealed no significant sequence divergence at the amino acid level suggesting conservation of function across the homoeogroups. Functional analysis of MSH7 through the use of RNAi loss-of-function transgenics was undertaken in diploid barley (Hordeum vulgare L.. Quantitative real-time PCR revealed several T0 lines with reduced MSH7 expression. Positive segregants from two T1 lines studied in detail showed reduced MSH7 expression when compared to transformed controls and null segregants. Expression of MSH6, another member of the mismatch repair family which is most closely related to the MSH7 gene, was not significantly reduced in these lines. In both T1 lines, reduced seed set in positive segregants was observed. Conclusion Results presented here indicate, for the first time, a distinct functional role for MSH7 in vivo and show that expression of this gene is necessary for wild-type levels of fertility. These observations suggest that MSH7 has an important function during meiosis and as such remains a candidate for Ph2.

Platinum sensitivity and DNA repair in a recently established panel of patient-derived ovarian carcinoma xenografts

Science.gov (United States)

Guffanti, Federica; Fratelli, Maddalena; Ganzinelli, Monica; Bolis, Marco; Ricci, Francesca; Bizzaro, Francesca; Chilà, Rosaria; Sina, Federica Paola; Fruscio, Robert; Lupia, Michela; Cavallaro, Ugo; Cappelletti, Maria Rosa; Generali, Daniele; Giavazzi, Raffaella; Damia, Giovanna

2018-01-01

A xenobank of patient-derived (PDX) ovarian tumor samples has been established consisting of tumors with different sensitivity to cisplatin (DDP), from very responsive to resistant. As the DNA repair pathway is an important driver in tumor response to DDP, we analyzed the mRNA expression of 20 genes involved in the nucleotide excision repair, fanconi anemia, homologous recombination, base excision repair, mismatch repair and translesion repair pathways and the methylation patterns of some of these genes. We also investigated the correlation with the response to platinum-based therapy. The mRNA levels of the selected genes were evaluated by Real Time-PCR (RT-PCR) with ad hoc validated primers and gene promoter methylation by pyrosequencing. All the DNA repair genes were variably expressed in all 42 PDX samples analyzed, with no particular histotype-specific pattern of expression. In high-grade serous/endometrioid PDXs, the CDK12 mRNA expression levels positively correlated with the expression of TP53BP1, PALB2, XPF and POLB. High-grade serous/endometrioid PDXs with TP53 mutations had significantly higher levels of POLQ, FANCD2, RAD51 and POLB than high-grade TP53 wild type PDXs. The mRNA levels of CDK12, PALB2 and XPF inversely associated with the in vivo DDP antitumor activity; higher CDK12 mRNA levels were associated with a higher recurrence rate in ovarian patients with low residual tumor. These data support the important role of CDK12 in the response to a platinum based therapy in ovarian patients. PMID:29872499

Molecular characteristics of mismatch repair genes in sporadic colorectal tumors in Czech patients

Czech Academy of Sciences Publication Activity Database

Vymetálková, Veronika; Slyšková, Jana; Korenková, Vlasta; Bielik, Ludovít; Langerová, Lucie; Procházka, Pavel; Rejhová, Alexandra; Schwarzová, L.; Pardini, B.; Naccarati, Alessio; Vodička, Pavel

2014-01-01

Roč. 15, č. 1 (2014), s. 17 ISSN 1471-2350 R&D Projects: GA AV ČR IAA500200917; GA ČR(CZ) GPP304/11/P715 Grant - others:GA MŠk(CZ) Prvouk-P27/LF1/1 Institutional support: RVO:68378041 ; RVO:86652036 Keywords : colorectal cancer * mismatch repair genes * expression levels Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.083, year: 2014

Repair of DNA treated with λ-irradiation and chemical carcinogens: Progress report, 1983-1987

International Nuclear Information System (INIS)

Goldthwait, D.A.

1987-08-01

Studies on the in vitro enzymatic mechanisms of DNA repair of chromatin structures are described. In addition new studies on signal transduction in cancer and in carcinogenesis are emphasized. We are using molecular biological approaches to three model systems, which we are developing. The first involves signal transduction controlling sis gene (platelet derived growth factor-β) mRNA levels in human glioblastoma cells. The second involves signal transduction in the activation of a long terminal repeat. The third involves an experiment designed to detect a tranposition event in a human cell. This progress report will summarize work on DNA repair of chromatin and then detail our progress in developing the three model systems. 59 refs., 14 figs., 7 tabs

PMS2 gene mutation results in DNA mismatch repair system failure in a case of adult granulosa cell tumor.

Science.gov (United States)

Wang, Wen-Chung; Lee, Ya-Ting; Lai, Yen-Chein

2017-03-27

Granulosa cell tumors are rare ovarian malignancies. Their characteristics include unpredictable indolent growth with malignant potential and late recurrence. Approximately 95% are of adult type. Recent molecular studies have characterized the FOXL2 402C > G mutation in adult granulosa cell tumor. Our previous case report showed that unique FOXL2 402C > G mutation and defective DNA mismatch repair system are associated with the development of adult granulosa cell tumor. In this study, the DNA sequences of four genes, MSH2, MLH1, MSH6, and PMS2, in the DNA mismatch repair system were determined via direct sequencing to elucidate the exact mechanism for the development of this granulosa cell tumor. The results showed that two missense germline mutations, T485K and N775L, inactivate the PMS2 gene. The results of this case study indicated that although FOXL2 402C > G mutation determines the development of granulosa cell tumor, PMS2 mutation may be the initial driver of carcinogenesis. Immunohistochemistry-based tumor testing for mismatch repair gene expression may be necessary for granulosa cell tumors to determine their malignant potential or if they are part of Lynch syndrome.

A cryptochrome-like protein is involved in the regulation of photosynthesis genes in Rhodobacter sphaeroides.

Science.gov (United States)

Hendrischk, Anne-Kathrin; Frühwirth, Sebastian Walter; Moldt, Julia; Pokorny, Richard; Metz, Sebastian; Kaiser, Gebhard; Jäger, Andreas; Batschauer, Alfred; Klug, Gabriele

2009-11-01

Blue light receptors belonging to the cryptochrome/photolyase family are found in all kingdoms of life. The functions of photolyases in repair of UV-damaged DNA as well as of cryptochromes in the light-dependent regulation of photomorphogenetic processes and in the circadian clock in plants and animals are well analysed. In prokaryotes, the only role of members of this protein family that could be demonstrated is DNA repair. Recently, we identified a gene for a cryptochrome-like protein (CryB) in the alpha-proteobacterium Rhodobacter sphaeroides. The protein lacks the typical C-terminal extension of cryptochromes, and is not related to the Cry DASH family. Here we demonstrate that CryB binds flavin adenine dinucleotide that can be photoreduced by blue light. CryB binds single-stranded DNA with very high affinity (K(d) approximately 10(-8) M) but double-stranded DNA and single-stranded RNA with far lower affinity (K(d) approximately 10(-6) M). Despite of that, no in vitro repair activity for pyrimidine dimers in single-stranded DNA could be detected. However, we show that CryB clearly affects the expression of genes for pigment-binding proteins and consequently the amount of photosynthetic complexes in R. sphaeroides. Thus, for the first time a role of a bacterial cryptochrome in gene regulation together with a biological function is demonstrated.

Inter-individual variation in nucleotide excision repair pathway is modulated by non-synonymous polymorphisms in ERCC4 and MBD4 genes

Energy Technology Data Exchange (ETDEWEB)

Allione, Alessandra, E-mail: alessandra.allione@hugef-torino.org [Human Genetics Foundation (HuGeF), Via Nizza 52, 10126 Turin (Italy); Guarrera, Simonetta; Russo, Alessia [Human Genetics Foundation (HuGeF), Via Nizza 52, 10126 Turin (Italy); Ricceri, Fulvio [Human Genetics Foundation (HuGeF), Via Nizza 52, 10126 Turin (Italy); Department of Medical Sciences, University of Turin, Via Santena 19, 10126 Turin (Italy); Purohit, Rituraj [Human Genetics Foundation (HuGeF), Via Nizza 52, 10126 Turin (Italy); Bioinformatics Division, School of Bio Sciences and Technology, Vellore Institute of Technology University, Vellore 632014, Tamil Nadu (India); Pagnani, Andrea; Rosa, Fabio; Polidoro, Silvia; Voglino, Floriana [Human Genetics Foundation (HuGeF), Via Nizza 52, 10126 Turin (Italy); Matullo, Giuseppe [Human Genetics Foundation (HuGeF), Via Nizza 52, 10126 Turin (Italy); Department of Medical Sciences, University of Turin, Via Santena 19, 10126 Turin (Italy)

2013-11-15

Highlights: • We reported a large inter-individual variability of NER capacity. • ERCC4 rs1800124 and MBD4 rs10342 nsSNP variants were associated with DNA repair capacity. • DNA–protein interaction analyses showed alteration of binding for ERCC4 and MBD4 variants. • A new possible cross-talk between NER and BER pathways has been reported. - Abstract: Inter-individual differences in DNA repair capacity (DRC) may lead to genome instability and, consequently, modulate individual cancer risk. Among the different DNA repair pathways, nucleotide excision repair (NER) is one of the most versatile, as it can eliminate a wide range of helix-distorting DNA lesions caused by ultraviolet light irradiation and chemical mutagens. We performed a genotype–phenotype correlation study in 122 healthy subjects in order to assess if any associations exist between phenotypic profiles of NER and DNA repair gene single nucleotide polymorphisms (SNPs). Individuals were genotyped for 768 SNPs with a custom Illumina Golden Gate Assay, and peripheral blood mononuclear cells (PBMCs) of the same subjects were tested for a NER comet assay to measure DRC after challenging cells by benzo(a)pyrene diolepoxide (BPDE). We observed a large inter-individual variability of NER capacity, with women showing a statistically significant lower DRC (mean ± SD: 6.68 ± 4.76; p = 0.004) than men (mean ± SD: 8.89 ± 5.20). Moreover, DRC was significantly lower in individuals carrying a variant allele for the ERCC4 rs1800124 non-synonymous SNP (nsSNP) (p = 0.006) and significantly higher in subjects with the variant allele of MBD4 rs2005618 SNP (p = 0.008), in linkage disequilibrium (r{sup 2} = 0.908) with rs10342 nsSNP. Traditional in silico docking approaches on protein–DNA and protein–protein interaction showed that Gly875 variant in ERCC4 (rs1800124) decreases the DNA–protein interaction and that Ser273 and Thr273 variants in MBD4 (rs10342) indicate complete loss of protein�

Manipulation of cell cycle progression can counteract the apparent loss of correction frequency following oligonucleotide-directed gene repair

Directory of Open Access Journals (Sweden)

Kmiec Eric B

2007-02-01

Full Text Available Abstract Background Single-stranded oligonucleotides (ssODN are used routinely to direct specific base alterations within mammalian genomes that result in the restoration of a functional gene. Despite success with the technique, recent studies have revealed that following repair events, correction frequencies decrease as a function of time, possibly due to a sustained activation of damage response signals in corrected cells that lead to a selective stalling. In this study, we use thymidine to slow down the replication rate to enhance repair frequency and to maintain substantial levels of correction over time. Results First, we utilized thymidine to arrest cells in G1 and released the cells into S phase, at which point specific ssODNs direct the highest level of correction. Next, we devised a protocol in which cells are maintained in thymidine following the repair reaction, in which the replication is slowed in both corrected and non-corrected cells and the initial correction frequency is retained. We also present evidence that cells enter a senescence state upon prolonged treatment with thymidine but this passage can be avoided by removing thymidine at 48 hours. Conclusion Taken together, we believe that thymidine may be used in a therapeutic fashion to enable the maintenance of high levels of treated cells bearing repaired genes.

Inducible error-prone repair in B. subtilis. Progress report, September 1, 1981-April 30, 1983

International Nuclear Information System (INIS)

Yasbin, R.E.

1982-12-01

Considerable progress has been made on determining the mechanisms of mutagenesis in B. subtilis and on elucidating the interactions between DNA repair systems and mutagenesis in this bacterium. Specifically, the B. subtilis W-reactivation system has been shown to involve a damage-specific (pyrimidine dimer) repair mechanism which may or may not be error-free. On the other hand, error-prone repair (as defined by the ability of cells to be mutated by low doses of uv) has been definitively established in this bacterium. The investigation of the genes controlling the error-prone repair system has revealed that uv mutagenesis is significantly decreased in cells carrying the recG13 mutation. In addition, cells lacking a functional excision repair system are hypermutable to EMS, although these cells are not hypersensitive to the killing activity of EMS. Both EMS and uv generate the same spectrum of mutants (reversions vs suppressors); however, cells lacking a functional excision repair system apparently generate more suppressor mutations when exposed to uv as compared to the other strains tested. A genomic library for B. subtilis has been established. This library will be specifically used to isolate a cloned fragment of DNA which codes for the major subunit of the Bacillus DNA polymerase III. However, this bank can also be used to isolate Bacillus genes which control most of the repair functions. Furthermore, we have begun the process of cloning the E. coli phr + gene in to B. subtilis

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

International Nuclear Information System (INIS)

Allen-Brady, Kristina; Camp, Nicola J

2005-01-01

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. 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. 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. 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

Frameshift mutational target gene analysis identifies similarities and differences in constitutional mismatch repair-deficiency and Lynch syndrome.

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Maletzki, Claudia; Huehns, Maja; Bauer, Ingrid; Ripperger, Tim; Mork, Maureen M; Vilar, Eduardo; Klöcking, Sabine; Zettl, Heike; Prall, Friedrich; Linnebacher, Michael

2017-07-01

Mismatch-repair deficient (MMR-D) malignancies include Lynch Syndrome (LS), which is secondary to germline mutations in one of the MMR genes, and the rare childhood-form of constitutional mismatch repair-deficiency (CMMR-D); caused by bi-allelic MMR gene mutations. A hallmark of LS-associated cancers is microsatellite instability (MSI), characterized by coding frameshift mutations (cFSM) in target genes. By contrast, tumors arising in CMMR-D patients are thought to display a somatic mutation pattern differing from LS. This study has the main goal to identify cFSM in MSI target genes relevant in CMMR-D and to compare the spectrum of common somatic mutations, including alterations in DNA polymerases POLE and D1 between LS and CMMR-D. CMMR-D-associated tumors harbored more somatic mutations compared to LS cases, especially in the TP53 gene and in POLE and POLD1, where novel mutations were additionally identified. Strikingly, MSI in classical mononucleotide markers BAT40 and CAT25 was frequent in CMMR-D cases. MSI-target gene analysis revealed mutations in CMMR-D-associated tumors, some of them known to be frequently hit in LS, such as RNaseT2, HT001, and TGFβR2. Our results imply a general role for these cFSM as potential new drivers of MMR-D tumorigenesis. © 2017 Wiley Periodicals, Inc.

nuvA, an Aspergillus nidulans gene involved in DNA repair and recombination, is a homologue of Saccharomyces cerevisiae RAD18 and Neurospora crassa uvs-2.

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Iwanejko, L; Cotton, C; Jones, G; Tomsett, B; Strike, P

1996-03-01

A 40 kb genomic clone and 2.3 kb EcoRI subclone that rescued the DNA repair and recombination defects of the Aspergillus nidulans nuvA11 mutant were isolated and the subclone sequenced. The subclone hybridized to a cosmid in a chromosome-specific library confirming the assignment of nuvA to linkage group IV and indicating its closeness to bimD. Amplification by PCR clarified the relative positions of nuvA and bimD. A region identified within the subclone, encoding a C3HC4 zinc finger motif, was used as a probe to retrieve a cDNA clone. Sequencing of this clone showed that the nuvA gene has an ORF of 1329 bp with two introns of 51 bp and 60 bp. Expression of nuvA appears to be extremely low. The putative NUVA polypeptide has two zinc finger motifs, a molecular mass of 48906 Da and has 39% identity with the Neurospora crassa uvs-2 and 25% identity with the Saccharomyces cerevisiae RAD18 translation products. Although mutations in nuvA, uvs-2 and RAD18 produce similar phenotypes, only the nuvA11 mutation affects meiotic recombination. A role for nuvA in both DNA repair and genetic recombination is proposed.

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

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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.

Effect of DNA polymerase inhibitors on DNA repair in intact and permeable human fibroblasts: Evidence that DNA polymerases δ and β are involved in DNA repair synthesis induced by N-methyl-N'-nitro-N-nitrosoguanidine

International Nuclear Information System (INIS)

Hammond, R.A.; Miller, M.R.; McClung, J.K.

1990-01-01

The involvement of DNA polymerases α, β, and δ in DNA repair synthesis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was investigated in human fibroblasts (HF). The effects of anti-(DNA polymerase α) monoclonal antibody, (p-n-butylphenyl)deoxyguanosine triphosphate (BuPdGTP), dideoxythymidine triphosphate (ddTTP), and aphidicolin on MNNG-induced DNA repair synthesis were investigated to dissect the roles of the different DNA polymerases. A subcellular system (permeable cells), in which DNA repair synthesis and DNA replication were differentiated by CsCl gradient centrifugation of BrdUMP density-labeled DNA, was used to examine the effects of the polymerase inhibitors. Another approach investigated the effects of several of these inhibitors of MNNG-induced DNA repair synthesis in intact cells by measuring the amount of [ 3 H]thymidine incorporated into repair DNA as determined by autoradiography and quantitation with an automated video image analysis system. In permeable cells, MNNG-induced DNA repair synthesis was inhibited 56% by 50 μg of aphidicolin/mL, 6% by 10 μM BuPdGTP, 13% by anti-(DNA polymerse α) monoclonal antibodies, and 29% by ddTTP. In intact cells, MNNG-induced DNA repair synthesis was inhibited 57% by 50 μg of aphidicolin/mL and was not significantly inhibited by microinjecting anti-(DNA polymerase α) antibodies into HF nuclei. These results indicate that both DNA polymerase δ and β are involved in repairing DNA damage caused by MNNG

Detoxification and repair process of ozone injury: From O3 uptake to gene expression adjustment

International Nuclear Information System (INIS)

Castagna, A.; Ranieri, A.

2009-01-01

Plants react to O 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 3 uptake, differences in O 3 tolerance cannot always be ascribed to changes in stomatal conductance but cell protective and repair processes should be taken into account. O 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 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.

DNA mismatch repair related gene expression as potential biomarkers to assess cadmium exposure in Arabidopsis seedlings

International Nuclear Information System (INIS)

Liu Wan; Zhou Qixing; Li Peijun; Gao Hairong; Han, Y.P.; Li, X.J.; Yang, Y.S.; Li Yanzhi

2009-01-01

In the current study, Arabidopsis seedlings were hydroponically grown on MS media containing cadmium (Cd) of 0-2.0 mg L -1 for 60 h of treatment. Gene expression profiles were used to relate exposure to Cd with some altered biological responses and/or specific growth effects. RT-PCR analysis was used to quantitate mRNA expression for seven genes known to be involved in DNA mismatch repair (MMR) system and cell division. Results indicated that Cd concentrations of 0.25-2.0 mg L -1 cause increased total soluble protein levels in shoots of Arabidopsis seedlings in an inverted U-shaped dose-response manner. Exposure to 0.25 and 0.5 mg L -1 of Cd dramatically induced expression of four genes (i.e. proliferating cell nuclear antigen 2 (atPCNA 2), MutL1 homolog (atMLH1), MutS 2 homolog (atMSH2) and atMSH3) and five genes (i.e. atPCNA1,2, atMLH1 and atMSH2,7), respectively, in shoots of Arabidopsis seedlings; Exposure to 1.0 mg L -1 of Cd significantly elevated expression of only two genes (atMSH6,7), but caused prominent inhibition in expression of three genes (atPCNA2, atMLH1 and atMSH3) in shoots of Arabidopsis seedlings. The expression alterations of the above genes were independent of any biological effects such as survival, fresh weight and chlorophyll level of shoots. However, shoots of Arabidopsis seedlings exposed to 2.0 mg L -1 of Cd exhibited statistically prominent repression in expression of these seven genes, and showed incipient reduction of fresh weight and chlorophyll level. This research provides data concerning sensitivity of expression profiles of atMLH1, atMSH2,3,6,7 and atPCNA1,2 genes in Arabidopsis seedlings to Cd exposure, as well as the potential use of these gene expression patterns as representative molecular biomarkers indicative of Cd exposure and related biological effects.

A Functional Role for the Epigenetic Regulator ING1 in Activity-induced Gene Expression in Primary Cortical Neurons.

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Leighton, Laura J; Zhao, Qiongyi; Li, Xiang; Dai, Chuanyang; Marshall, Paul R; Liu, Sha; Wang, Yi; Zajaczkowski, Esmi L; Khandelwal, Nitin; Kumar, Arvind; Bredy, Timothy W; Wei, Wei

2018-01-15

Epigenetic regulation of activity-induced gene expression involves multiple levels of molecular interaction, including histone and DNA modifications, as well as mechanisms of DNA repair. Here we demonstrate that the genome-wide deposition of inhibitor of growth family member 1 (ING1), which is a central epigenetic regulatory protein, is dynamically regulated in response to activity in primary cortical neurons. ING1 knockdown leads to decreased expression of genes related to synaptic plasticity, including the regulatory subunit of calcineurin, Ppp3r1. In addition, ING1 binding at a site upstream of the transcription start site (TSS) of Ppp3r1 depends on yet another group of neuroepigenetic regulatory proteins, the Piwi-like family, which are also involved in DNA repair. These findings provide new insight into a novel mode of activity-induced gene expression, which involves the interaction between different epigenetic regulatory mechanisms traditionally associated with gene repression and DNA repair. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Inactivation of DNA mismatch repair by variants of uncertain significance in the PMS2 gene.

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Drost, Mark; Koppejan, Hester; de Wind, Niels

2013-11-01

Lynch syndrome (LS) is a common cancer predisposition caused by an inactivating mutation in one of four DNA mismatch repair (MMR) genes. Frequently a variant of uncertain significance (VUS), rather than an obviously pathogenic mutation, is identified in one of these genes. The inability to define pathogenicity of such variants precludes targeted healthcare. Here, we have modified a cell-free assay to test VUS in the MMR gene PMS2 for functional activity. We have analyzed nearly all VUS in PMS2 found thus far and describe loss of MMR activity for five, suggesting the applicability of the assay for diagnosis of LS. © 2013 WILEY PERIODICALS, INC.

DNA demethylation by 5-aza-2-deoxycytidine treatment abrogates 17 beta-estradiol-induced cell growth and restores expression of DNA repair genes in human breast cancer cells.

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Singh, Kamaleshwar P; Treas, Justin; Tyagi, Tulika; Gao, Weimin

2012-03-01

Prolonged exposure to elevated levels of estrogen is a risk factor for breast cancer. Though increased cell growth and loss of DNA repair capacity is one of the proposed mechanisms for estrogen-induced cancers, the mechanism through which estrogen induces cell growth and decreases DNA repair capacity is not clear. DNA hypermethylation is known to inactivate DNA repair genes and apoptotic response in cancer cells. Therefore, the objective of this study was to determine the role of DNA hypermethylation in estrogen-induced cell growth and regulation of DNA repair genes expression in breast cancer cells. To achieve this objective, the estrogen-responsive MCF-7 cells either pretreated with 5-aza-2-deoxycytidine (5-aza-dC) or untreated (as control) were exposed to 17 beta-estradiol (E2), and its effect on cell growth and expression of DNA repair genes were measured. The result revealed that 5-aza-dC abrogates the E2-induced growth in MCF-7 cells. An increased expression of OGG1, MSH4, and MLH1 by 5-aza-dC treatment alone, suggest the DNA hypermethylation as a potential cause for decreased expression of these genes in MCF-7 cells. The decreased expression of ERCC1, XPC, OGG1, and MLH1 by E2 alone and its restoration by co-treatment with 5-aza-dC further suggest that E2 reduces the expression of these DNA repair genes potentially through promoter hypermethylation. Reactivation of mismatch repair (MMR) gene MLH1 and abrogation of E2-induced cell growth by 5-aza-dC treatment suggest that estrogen causes increased growth in breast cancer cells potentially through the inhibition of MMR-mediated apoptotic response. In summary, this study suggests that estrogen increases cell growth and decreases the DNA repair capacity in breast cancer cells, at least in part, through epigenetic mechanism. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Development and applications of Bacillus subtilis test systems for mutagens, involving DNA-repair deficiency and suppressible auxotrophic mutations

International Nuclear Information System (INIS)

Tanooka, H.

1977-01-01

A mutagen-tester of Bacillus subtilis was constructed and tested with known carcinogens. The parental strain HA101 of Okubo and Yanagida carrying suppressible nonsense mutations in his and met genes was transformed to carry an excision-repair deficiency mutation. The constructed strain TKJ5211 showed a 20-30-fold higher sensitivity for His + reversion than the parental strain when treated with UV and UV-mimetic chemicals but unchanged mutation frequency with X-rays and methyl methanesulfonate. The tester strain was used in a spot test of 30 selected chemicals and also for testing with liver homogenate activation. The results showed an almost equivalent but somewhat broader detection spectrum than the Salmonella typhimurium TA100 system. Another test method used a pair of B. subtilis strains differing in their DNA-repair capacity, i.e. the most UV-sensitive mutant HJ-15 and a wild-type strain, to detect repair-dependent DNA damage produced by chemicals. Spores could be used in either test

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

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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

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

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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.

EGR1 induces tenogenic differentiation of tendon stem cells and promotes rabbit rotator cuff repair.

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Tao, Xu; Liu, Junpeng; Chen, Lei; Zhou, You; Tang, Kanglai

2015-01-01

The rate of healing failure after surgical repair of chronic rotator cuff tears is considerably high. The aim of this study was to investigate the function of the zinc finger transcription factor early growth response 1 (EGR1) in the differentiation of tendon stem cells (TSCs) and in tendon formation, healing, and tendon tear repair using an animal model of rotator cuff repair. Tenocyte, adipocyte, osteocyte, and chondrocyte differentiation as well as the expression of related genes were determined in EGR1-overexpressing TSCs (EGR1-TSCs) using tissue-specific staining, immunofluorescence staining, quantitative PCR, and western blotting. A rabbit rotator cuff repair model was established, and TSCs and EGR1-TSCs in a fibrin glue carrier were applied onto repair sites. The rabbits were sacrificed 8 weeks after repair operation, and tissues were histologically evaluated and tenocyte-related gene expression was determined. EGR1 induced tenogenic differentiation of TSCs and inhibited non-tenocyte differentiation of TSCs. Furthermore, EGR1 promoted tendon repair in a rabbit model of rotator cuff injury. The BMP12/Smad1/5/8 signaling pathway was involved in EGR1-induced tenogenic differentiation and rotator cuff tendon repair. EGR1 plays a key role in tendon formation, healing, and repair through BMP12/Smad1/5/8 pathway. EGR1-TSCs is a promising treatment for rotator cuff tendon repair surgeries. © 2015 S. Karger AG, Basel.

EGR1 Induces Tenogenic Differentiation of Tendon Stem Cells and Promotes Rabbit Rotator Cuff Repair

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Xu Tao

2015-01-01

Full Text Available Background/Aims: The rate of healing failure after surgical repair of chronic rotator cuff tears is considerably high. The aim of this study was to investigate the function of the zinc finger transcription factor early growth response 1 (EGR1 in the differentiation of tendon stem cells (TSCs and in tendon formation, healing, and tendon tear repair using an animal model of rotator cuff repair. Methods: Tenocyte, adipocyte, osteocyte, and chondrocyte differentiation as well as the expression of related genes were determined in EGR1-overexpressing TSCs (EGR1-TSCs using tissue-specific staining, immunofluorescence staining, quantitative PCR, and western blotting. A rabbit rotator cuff repair model was established, and TSCs and EGR1-TSCs in a fibrin glue carrier were applied onto repair sites. The rabbits were sacrificed 8 weeks after repair operation, and tissues were histologically evaluated and tenocyte-related gene expression was determined. Results: EGR1 induced tenogenic differentiation of TSCs and inhibited non-tenocyte differentiation of TSCs. Furthermore, EGR1 promoted tendon repair in a rabbit model of rotator cuff injury. The BMP12/Smad1/5/8 signaling pathway was involved in EGR1-induced tenogenic differentiation and rotator cuff tendon repair. Conclusion: EGR1 plays a key role in tendon formation, healing, and repair through BMP12/Smad1/5/8 pathway. EGR1-TSCs is a promising treatment for rotator cuff tendon repair surgeries.

Targeting DNA repair systems in antitubercular drug development.

Science.gov (United States)

Minias, Alina; Brzostek, Anna; Dziadek, Jaroslaw

2018-01-28

Infections with Mycobacterium tuberculosis, the causative agent of tuberculosis, are difficult to treat using currently available chemotherapeutics. Clinicians agree on the urgent need for novel drugs to treat tuberculosis. In this mini review, we summarize data that prompts the consideration of DNA repair-associated proteins as targets for the development of new antitubercular compounds. We discuss data, including gene expression data, that highlight the importance of DNA repair genes during the pathogenic cycle as well as after exposure to antimicrobials currently in use. Specifically, we report experiments on determining the essentiality of DNA repair-related genes. We report the availability of protein crystal structures and summarize discovered protein inhibitors. Further, we describe phenotypes of available gene mutants of M. tuberculosis and model organisms Mycobacterium bovis and Mycobacterium smegmatis. We summarize experiments regarding the role of DNA repair-related proteins in pathogenesis and virulence performed both in vitro and in vivo during the infection of macrophages and animals. We detail the role of DNA repair genes in acquiring mutations, which influence the rate of drug resistance acquisition. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Hsp90: A New Player in DNA Repair?

Directory of Open Access Journals (Sweden)

Rosa Pennisi

2015-10-01

Full Text Available Heat shock protein 90 (Hsp90 is an evolutionary conserved molecular chaperone that, together with Hsp70 and co-chaperones makes up the Hsp90 chaperone machinery, stabilizing and activating more than 200 proteins, involved in protein homeostasis (i.e., proteostasis, transcriptional regulation, chromatin remodeling, and DNA repair. Cells respond to DNA damage by activating complex DNA damage response (DDR pathways that include: (i cell cycle arrest; (ii transcriptional and post-translational activation of a subset of genes, including those associated with DNA repair; and (iii triggering of programmed cell death. The efficacy of the DDR pathways is influenced by the nuclear levels of DNA repair proteins, which are regulated by balancing between protein synthesis and degradation as well as by nuclear import and export. The inability to respond properly to either DNA damage or to DNA repair leads to genetic instability, which in turn may enhance the rate of cancer development. Multiple components of the DNA double strand breaks repair machinery, including BRCA1, BRCA2, CHK1, DNA-PKcs, FANCA, and the MRE11/RAD50/NBN complex, have been described to be client proteins of Hsp90, which acts as a regulator of the diverse DDR pathways. Inhibition of Hsp90 actions leads to the altered localization and stabilization of DDR proteins after DNA damage and may represent a cell-specific and tumor-selective radiosensibilizer. Here, the role of Hsp90-dependent molecular mechanisms involved in cancer onset and in the maintenance of the genome integrity is discussed and highlighted.

Polymorphic Variation in Double Strand Break Repair Gene in Indian Population: A Comparative Approach with Worldwide Ethnic Group Variations.

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Mandal, Raju Kumar; Mittal, Rama Devi

2018-04-01

DNA repair capacity is essential in maintaining cellular functions and homeostasis. Identification of genetic polymorphisms responsible for reduced DNA repair capacity may allow better cancer prevention. Double strand break repair pathway plays critical roles in maintaining genome stability. Present study was conducted to determine distribution of XRCC3 Exon 7 (C18067T, rs861539) and XRCC7 Intron 8 (G6721T, rs7003908) gene polymorphisms in North Indian population and compare with different populations globally. The genotype assays were performed in 224 normal healthy individuals of similar ethnicity using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Allelic frequencies of wild type were 79% (C) in XRCC3 Exon 7 C > T and 57% (G) in XRCC7 Intron 8 (G > T) 57% (G) observed. On the other hand, the variant allele frequency were 21% (T) in XRCC3 Exon 7 C > T and 43% (T) in XRCC7 Intron 8 G > T respectively. Major differences from other ethnic populations were observed. Our results suggest that frequency in these DNA repair genes exhibit distinctive pattern in India that could be attributed to ethnicity variation. This could assist in high-risk screening of humans exposed to environmental carcinogens and cancer predisposition in different ethnic groups.

Predictive models for mutations in mismatch repair genes: implication for genetic counseling in developing countries

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Monteiro Santos, Erika Maria [Graduation Program, AC Camargo Hospital, Sao Paulo (Brazil); International Center of Research and Training (CIPE), AC Camargo Hospital, Sao Paulo (Brazil); Silva Junior, Wilson Araujo da [Sao Paulo University, Department of Genetics, Medical School of Ribeirao Preto, Ribeirao Preto (Brazil); Carraro, Dirce Maria [Graduation Program, AC Camargo Hospital, Sao Paulo (Brazil); International Center of Research and Training (CIPE), AC Camargo Hospital, Sao Paulo (Brazil); Rossi, Benedito Mauro; Valentin, Mev Dominguez [Graduation Program, AC Camargo Hospital, Sao Paulo (Brazil); Carneiro, Felipe [Graduation Program, AC Camargo Hospital, Sao Paulo (Brazil); International Center of Research and Training (CIPE), AC Camargo Hospital, Sao Paulo (Brazil); Oliveira, Ligia Petrolini de [Graduation Program, AC Camargo Hospital, Sao Paulo (Brazil); Oliveira Ferreira, Fabio de; Junior, Samuel Aguiar [Graduation Program, AC Camargo Hospital, Sao Paulo (Brazil); Hereditary Colorectal Cancer Registry, AC Camargo Hospital, Sao Paulo (Brazil); Nakagawa, Wilson Toshihiko [Hereditary Colorectal Cancer Registry, AC Camargo Hospital, Sao Paulo (Brazil); Gomy, Israel [Graduation Program, AC Camargo Hospital, Sao Paulo (Brazil); Sao Paulo University, Department of Genetics, Medical School of Ribeirao Preto, Ribeirao Preto (Brazil); Faria Ferraz, Victor Evangelista de [Sao Paulo University, Department of Genetics, Medical School of Ribeirao Preto, Ribeirao Preto (Brazil)

2012-02-09

Lynch syndrome (LS) is the most common form of inherited predisposition to colorectal cancer (CRC), accounting for 2-5% of all CRC. LS is an autosomal dominant disease characterized by mutations in the mismatch repair genes mutL homolog 1 (MLH1), mutS homolog 2 (MSH2), postmeiotic segregation increased 1 (PMS1), post-meiotic segregation increased 2 (PMS2) and mutS homolog 6 (MSH6). Mutation risk prediction models can be incorporated into clinical practice, facilitating the decision-making process and identifying individuals for molecular investigation. This is extremely important in countries with limited economic resources. This study aims to evaluate sensitivity and specificity of five predictive models for germline mutations in repair genes in a sample of individuals with suspected Lynch syndrome. Blood samples from 88 patients were analyzed through sequencing MLH1, MSH2 and MSH6 genes. The probability of detecting a mutation was calculated using the PREMM, Barnetson, MMRpro, Wijnen and Myriad models. To evaluate the sensitivity and specificity of the models, receiver operating characteristic curves were constructed. Of the 88 patients included in this analysis, 31 mutations were identified: 16 were found in the MSH2 gene, 15 in the MLH1 gene and no pathogenic mutations were identified in the MSH6 gene. It was observed that the AUC for the PREMM (0.846), Barnetson (0.850), MMRpro (0.821) and Wijnen (0.807) models did not present significant statistical difference. The Myriad model presented lower AUC (0.704) than the four other models evaluated. Considering thresholds of ≥ 5%, the models sensitivity varied between 1 (Myriad) and 0.87 (Wijnen) and specificity ranged from 0 (Myriad) to 0.38 (Barnetson). The Barnetson, PREMM, MMRpro and Wijnen models present similar AUC. The AUC of the Myriad model is statistically inferior to the four other models.

Predictive models for mutations in mismatch repair genes: implication for genetic counseling in developing countries

International Nuclear Information System (INIS)

Monteiro Santos, Erika Maria; Silva Junior, Wilson Araujo da; Carraro, Dirce Maria; Rossi, Benedito Mauro; Valentin, Mev Dominguez; Carneiro, Felipe; Oliveira, Ligia Petrolini de; Oliveira Ferreira, Fabio de; Junior, Samuel Aguiar; Nakagawa, Wilson Toshihiko; Gomy, Israel; Faria Ferraz, Victor Evangelista de

2012-01-01

Lynch syndrome (LS) is the most common form of inherited predisposition to colorectal cancer (CRC), accounting for 2-5% of all CRC. LS is an autosomal dominant disease characterized by mutations in the mismatch repair genes mutL homolog 1 (MLH1), mutS homolog 2 (MSH2), postmeiotic segregation increased 1 (PMS1), post-meiotic segregation increased 2 (PMS2) and mutS homolog 6 (MSH6). Mutation risk prediction models can be incorporated into clinical practice, facilitating the decision-making process and identifying individuals for molecular investigation. This is extremely important in countries with limited economic resources. This study aims to evaluate sensitivity and specificity of five predictive models for germline mutations in repair genes in a sample of individuals with suspected Lynch syndrome. Blood samples from 88 patients were analyzed through sequencing MLH1, MSH2 and MSH6 genes. The probability of detecting a mutation was calculated using the PREMM, Barnetson, MMRpro, Wijnen and Myriad models. To evaluate the sensitivity and specificity of the models, receiver operating characteristic curves were constructed. Of the 88 patients included in this analysis, 31 mutations were identified: 16 were found in the MSH2 gene, 15 in the MLH1 gene and no pathogenic mutations were identified in the MSH6 gene. It was observed that the AUC for the PREMM (0.846), Barnetson (0.850), MMRpro (0.821) and Wijnen (0.807) models did not present significant statistical difference. The Myriad model presented lower AUC (0.704) than the four other models evaluated. Considering thresholds of ≥ 5%, the models sensitivity varied between 1 (Myriad) and 0.87 (Wijnen) and specificity ranged from 0 (Myriad) to 0.38 (Barnetson). The Barnetson, PREMM, MMRpro and Wijnen models present similar AUC. The AUC of the Myriad model is statistically inferior to the four other models

Stably Expressed Genes Involved in Basic Cellular Functions.

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Kejian Wang

Full Text Available Stably Expressed Genes (SEGs whose expression varies within a narrow range may be involved in core cellular processes necessary for basic functions. To identify such genes, we re-analyzed existing RNA-Seq gene expression profiles across 11 organs at 4 developmental stages (from immature to old age in both sexes of F344 rats (n = 4/group; 320 samples. Expression changes (calculated as the maximum expression / minimum expression for each gene of >19000 genes across organs, ages, and sexes ranged from 2.35 to >109-fold, with a median of 165-fold. The expression of 278 SEGs was found to vary ≤4-fold and these genes were significantly involved in protein catabolism (proteasome and ubiquitination, RNA transport, protein processing, and the spliceosome. Such stability of expression was further validated in human samples where the expression variability of the homologous human SEGs was significantly lower than that of other genes in the human genome. It was also found that the homologous human SEGs were generally less subject to non-synonymous mutation than other genes, as would be expected of stably expressed genes. We also found that knockout of SEG homologs in mouse models was more likely to cause complete preweaning lethality than non-SEG homologs, corroborating the fundamental roles played by SEGs in biological development. Such stably expressed genes and pathways across life-stages suggest that tight control of these processes is important in basic cellular functions and that perturbation by endogenous (e.g., genetics or exogenous agents (e.g., drugs, environmental factors may cause serious adverse effects.

Repair of DNA damage in Deinococcus radiodurans

International Nuclear Information System (INIS)

Evans, D.M.

1984-01-01

The repair of DNA lesions in Deinococcus radiodurans was examined with particular reference to DNA excision repair of ultraviolet light (UV) induced pyrimidine dimers. The characteristics of excision repair via UV endonucleases α and β in vivo varied with respect to (a) the substrate range of the enzymes, (b) the rate of repair of DNA damage (c) the requirement for a protein synthesised in response to DNA damage to attenuate exonuclease action at repairing regions. UV endonuclease α is postulated to incise DNA in a different manner from UV endonuclease β thus defining the method of subsequent repair. Several DNA damage specific endonuclease activities independent of α and β are described. Mutations of the uvsA, uvsF and uvsG genes resulted in an increase in single-strand breaks in response to DNA damage producing uncontrolled DNA degradation. Evidence is presented that these genes have a role in limiting the access of UV endonuclease β to DNA lesions. uvsF and uvsG are also shown to be linked to the mtoA gene. Mutation of uvsH and reo-1 produces further distinct phenotypes which are discussed. An overall model of excision repair of DNA damage in Deinococcus radiodurans is presented. (author)

DNA repair and recombination in higher plants: insights from comparative genomics of arabidopsis and rice

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Choudhury Swarup

2010-07-01

Full Text Available Abstract Background The DNA repair and recombination (DRR proteins protect organisms against genetic damage, caused by environmental agents and other genotoxic agents, by removal of DNA lesions or helping to abide them. Results We identified genes potentially involved in DRR mechanisms in Arabidopsis and rice using similarity searches and conserved domain analysis against proteins known to be involved in DRR in human, yeast and E. coli. As expected, many of DRR genes are very similar to those found in other eukaryotes. Beside these eukaryotes specific genes, several prokaryotes specific genes were also found to be well conserved in plants. In Arabidopsis, several functionally important DRR gene duplications are present, which do not occur in rice. Among DRR proteins, we found that proteins belonging to the nucleotide excision repair pathway were relatively more conserved than proteins needed for the other DRR pathways. Sub-cellular localization studies of DRR gene suggests that these proteins are mostly reside in nucleus while gene drain in between nucleus and cell organelles were also found in some cases. Conclusions The similarities and dissimilarities in between plants and other organisms' DRR pathways are discussed. The observed differences broaden our knowledge about DRR in the plants world, and raises the potential question of whether differentiated functions have evolved in some cases. These results, altogether, provide a useful framework for further experimental studies in these organisms.

DNA repair and recombination in higher plants: insights from comparative genomics of Arabidopsis and rice.

Science.gov (United States)

Singh, Sanjay K; Roy, Sujit; Choudhury, Swarup Roy; Sengupta, Dibyendu N

2010-07-21

The DNA repair and recombination (DRR) proteins protect organisms against genetic damage, caused by environmental agents and other genotoxic agents, by removal of DNA lesions or helping to abide them. We identified genes potentially involved in DRR mechanisms in Arabidopsis and rice using similarity searches and conserved domain analysis against proteins known to be involved in DRR in human, yeast and E. coli. As expected, many of DRR genes are very similar to those found in other eukaryotes. Beside these eukaryotes specific genes, several prokaryotes specific genes were also found to be well conserved in plants. In Arabidopsis, several functionally important DRR gene duplications are present, which do not occur in rice. Among DRR proteins, we found that proteins belonging to the nucleotide excision repair pathway were relatively more conserved than proteins needed for the other DRR pathways. Sub-cellular localization studies of DRR gene suggests that these proteins are mostly reside in nucleus while gene drain in between nucleus and cell organelles were also found in some cases. The similarities and dissimilarities in between plants and other organisms' DRR pathways are discussed. The observed differences broaden our knowledge about DRR in the plants world, and raises the potential question of whether differentiated functions have evolved in some cases. These results, altogether, provide a useful framework for further experimental studies in these organisms.

Paradoxical DNA repair and peroxide resistance gene conservation in Bacillus pumilus SAFR-032.

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Jason Gioia

Full Text Available BACKGROUND: Bacillus spores are notoriously resistant to unfavorable conditions such as UV radiation, gamma-radiation, H2O2, desiccation, chemical disinfection, or starvation. Bacillus pumilus SAFR-032 survives standard decontamination procedures of the Jet Propulsion Lab spacecraft assembly facility, and both spores and vegetative cells of this strain exhibit elevated resistance to UV radiation and H2O2 compared to other Bacillus species. PRINCIPAL FINDINGS: The genome of B. pumilus SAFR-032 was sequenced and annotated. Lists of genes relevant to DNA repair and the oxidative stress response were generated and compared to B. subtilis and B. licheniformis. Differences in conservation of genes, gene order, and protein sequences are highlighted because they potentially explain the extreme resistance phenotype of B. pumilus. The B. pumilus genome includes genes not found in B. subtilis or B. licheniformis and conserved genes with sequence divergence, but paradoxically lacks several genes that function in UV or H2O2 resistance in other Bacillus species. SIGNIFICANCE: This study identifies several candidate genes for further research into UV and H2O2 resistance. These findings will help explain the resistance of B. pumilus and are applicable to understanding sterilization survival strategies of microbes.

Expression profiles of genes involved in tanshinone biosynthesis of ...

Indian Academy of Sciences (India)

Expression profiles of genes involved in tanshinone biosynthesis of two. Salvia miltiorrhiza genotypes with different tanshinone contents. Zhenqiao Song, Jianhua Wang and Xingfeng Li. J. Genet. 95, 433–439. Table 1. S. miltiorrhiza genes and primer pairs used for qRT-PCR. Gene. GenBank accession. Primer name.

Coverage analysis of lists of genes involved in heterogeneous ...

Indian Academy of Sciences (India)

Genes involved in myopathies: 82 genes, based on the disease groups ... 605517 Muscular dystrophy-dystroglycanopathy (congenital with brain and eye ..... Epilepsy, X-linked, with variable learning disabilities and behavior disorders. 300491.

Epigenetic changes of DNA repair genes in cancer

OpenAIRE

Lahtz, Christoph; Pfeifer, Gerd P.

2011-01-01

‘Every Hour Hurts, The Last One Kills'. That is an old saying about getting old. Every day, thousands of DNA damaging events take place in each cell of our body, but efficient DNA repair systems have evolved to prevent that. However, our DNA repair system and that of most other organisms are not as perfect as that of Deinococcus radiodurans, for example, which is able to repair massive amounts of DNA damage at one time. In many instances, accumulation of DNA damage has been linked to cancer, ...

A human homolog of the yeast nucleotide excision repair gene MMS19 interacts with transcription repair factor TFIIH through 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); A.P.M. Eker (André); G. Weeda (Geert); J-M. Egly (Jean-Marc); J.H.J. Hoeijmakers (Jan)

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

Some important advances in DNA repair study on the mammalian cells

International Nuclear Information System (INIS)

Xia Shouxuan.

1991-01-01

In the recent years the study of DNA damage and repair in the mammalian cells has gone deeply at gene level and got the following advances: (1) For a long time DNA has been considered to be an uniform unit in case of damage and repair. Now this concept should be replaced by the non-random distribution of damage and heterogenous repair in the genome. These would allow us to study cellular mutagenesis, carcinogenesis, aging and dying processes in great detail, and would be beneficial to the elucidation of mechanisms of radiation sickness and chemical toxicology. (2) The advent of new techniques in molecular biology has made it possible to isolate and clone the human DNA repair genes. Up to now more than ten human DNA repair genes have been cloned and these works would have an important impact on the theoretical and practical study in this field. Because DNA repair system is very complicate, voluminous work should be done in the future. (3) The technique of gene transfer has been efficiently used in the study of DNA repair in mammalian cells and has made great contribution in the cellular engineering. It could modify the genetic behavior of the gene-accepting cells, and enhance the DNA repair ability to physical and chemical damages. Human gene therapy for DNA deficient diseases is now on the day

Homozygous germ-line mutation of the PMS2 mismatch repair gene: a unique case report of constitutional mismatch repair deficiency (CMMRD).

Science.gov (United States)

Ramchander, N C; Ryan, N A J; Crosbie, E J; Evans, D G

2017-04-05

Constitutional mismatch repair deficiency syndrome results from bi-allelic inheritance of mutations affecting the key DNA mismatch repair genes: MLH1, MSH2, MSH6 or PMS2. Individuals with bi-allelic mutations have a dysfunctional mismatch repair system from birth; as a result, constitutional mismatch repair deficiency syndrome is characterised by early onset malignancies. Fewer than 150 cases have been reported in the literature over the past 20 years. This is the first report of the founder PMS2 mutation - NM_000535.5:c.1500del (p.Val501TrpfsTer94) in exon 11 and its associated cancers in this family. The proband is 30 years old and is alive today. She is of Pakistani ethnic origin and a product of consanguinity. She initially presented aged 24 with painless bleeding per-rectum from colorectal polyps and was referred to clinical genetics. Clinical examination revealed two café-au-lait lesions, lichen planus, and a dermoid cyst. Her sister had been diagnosed in childhood with an aggressive brain tumour followed by colorectal cancer. During follow up, the proband developed 37 colorectal adenomatous polyps, synchronous ovarian and endometrial adenocarcinomas, and ultimately a metachronous gastric adenocarcinoma. DNA sequencing of peripheral lymphocytes revealed a bi-allelic inheritance of the PMS2 mutation NM_000535.5:c.1500del (p.Val501TrpfsTer94) in exon 11. Ovarian tumour tissue demonstrated low microsatellite instability. To date, she has had a total abdominal hysterectomy, bilateral salpingo-oophorectomy, and a total gastrectomy. Aspirin and oestrogen-only hormone replacement therapy provide some chemoprophylaxis and manage postmenopausal symptoms, respectively. An 18-monthly colonoscopy surveillance programme has led to the excision of three high-grade dysplastic colorectal tubular adenomatous polyps. The proband's family pedigree displays multiple relatives with cancers including a likely case of 'true' Turcot syndrome. Constitutional mismatch repair

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...... of 56 consecutive patients with colorectal cancer aged less than 45 years were stratified into three groups based on clinical criteria: 'Amsterdam criteria', 'high risk' and 'young onset only'. Immunohistochemistry for four MMR proteins was carried out and the rate of compliance with clinical guidelines...

Differences in mutagenic and recombinational DNA repair in enterobacteria

International Nuclear Information System (INIS)

Sedgwick, S.G.; Goodwin, P.A.

1985-01-01

The incidence of recombinational DNA repair and inducible mutagenic DNA repair has been examined in Escherichia coli and 11 related species of enterobacteria. Recombinational repair was found to be a common feature of the DNA repair repertoire of at least 6 genera of enterobacteria. This conclusion is based on observations of (i) damage-induced synthesis of RecA-like proteins, (ii) nucleotide hybridization between E. coli recA sequences and some chromosomal DNAs, and (iii) recA-negative complementation by plasmids showing SOS-inducible expression of truncated E. coli recA genes. The mechanism of DNA damage-induced gene expression is therefore sufficiently conserved to allow non-E. coli regulatory elements to govern expression of these cloned truncated E. coli recA genes. In contrast, the process of mutagenic repair, which uses umuC+ umuD+ gene products in E. coli, appeared less widespread. Little ultraviolet light-induced mutagenesis to rifampicin resistance was detected outside the genus Escherichia, and even within the genus induced mutagenesis was detected in only 3 out of 6 species. Nucleotide hybridization showed that sequences like the E. coli umuCD+ gene are not found in these poorly mutable organisms. Evolutionary questions raised by the sporadic incidence of inducible mutagenic repair are discussed

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.

TopBP1 associates with NBS1 and is involved in homologous recombination repair

International Nuclear Information System (INIS)

Morishima, Ken-ichi; Sakamoto, Shuichi; Kobayashi, Junya; Izumi, Hideki; Suda, Tetsuji; Matsumoto, Yoshiyuki; Tauchi, Hiroshi; Ide, Hiroshi; Komatsu, Kenshi; Matsuura, Shinya

2007-01-01

TopBP1 is involved in DNA replication and DNA damage checkpoint. Recent studies have demonstrated that TopBP1 is a direct positive effecter of ATR. However, it is not known how TopBP1 recognizes damaged DNA. Here, we show that TopBP1 formed nuclear foci after exposure to ionizing radiation, but such TopBP1 foci were abolished in Nijmegen breakage syndrome cells. We also show that TopBP1 physically associated with NBS1 in vivo. These results suggested that NBS1 might regulate TopBP1 recruitment to the sites of DNA damage. TopBP1-depleted cells showed hypersensitivity to Mitomycin C and ionizing radiation, an increased frequency of sister-chromatid exchange level, and a reduced frequency of DNA double-strand break induced homologous recombination repair. Together, these results suggested that TopBP1 might be a mediator of DNA damage signaling from NBS1 to ATR and promote homologous recombination repair

Direct Involvement of Retinoblastoma Family Proteins in DNA Repair by Non-homologous End-Joining

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Rebecca Cook

2015-03-01

Full Text Available Deficiencies in DNA double-strand break (DSB repair lead to genetic instability, a recognized cause of cancer initiation and evolution. We report that the retinoblastoma tumor suppressor protein (RB1 is required for DNA DSB repair by canonical non-homologous end-joining (cNHEJ. Support of cNHEJ involves a mechanism independent of RB1’s cell-cycle function and depends on its amino terminal domain with which it binds to NHEJ components XRCC5 and XRCC6. Cells with engineered loss of RB family function as well as cancer-derived cells with mutational RB1 loss show substantially reduced levels of cNHEJ. RB1 variants disabled for the interaction with XRCC5 and XRCC6, including a cancer-associated variant, are unable to support cNHEJ despite being able to confer cell-cycle control. Our data identify RB1 loss as a candidate driver of structural genomic instability and a causative factor for cancer somatic heterogeneity and evolution.

Biosensor-controlled gene therapy/drug delivery with nanoparticles for nanomedicine

Science.gov (United States)

Prow, Tarl W.; Rose, William A.; Wang, Nan; Reece, Lisa M.; Lvov, Yuri; Leary, James F.

2005-04-01

Nanomedicine involves cell-by-cell regenerative medicine, either repairing cells one at a time or triggering apoptotic pathways in cells that are not repairable. Multilayered nanoparticle systems are being constructed for the targeted delivery of gene therapy to single cells. Cleavable shells containing targeting, biosensing, and gene therapeutic molecules are being constructed to direct nanoparticles to desired intracellular targets. Therapeutic gene sequences are controlled by biosensor-activated control switches to provide the proper amount of gene therapy on a single cell basis. The central idea is to set up gene therapy "nanofactories" inside single living cells. Molecular biosensors linked to these genes control their expression. Gene delivery is started in response to a biosensor detected problem; gene delivery is halted when the cell response indicates that more gene therapy is not needed. Cell targeting of nanoparticles, both nanocrystals and nanocapsules, has been tested by a combination of fluorescent tracking dyes, fluorescence microscopy and flow cytometry. Intracellular targeting has been tested by confocal microscopy. Successful gene delivery has been visualized by use of GFP reporter sequences. DNA tethering techniques were used to increase the level of expression of these genes. Integrated nanomedical systems are being designed, constructed, and tested in-vitro, ex-vivo, and in small animals. While still in its infancy, nanomedicine represents a paradigm shift in thinking-from destruction of injured cells by surgery, radiation, chemotherapy to cell-by-cell repair within an organ and destruction of non-repairable cells by natural apoptosis.

Molecular genetic and biochemical analyses of a DNA repair gene from Serratia marcescens

International Nuclear Information System (INIS)

Murphy, K.E.

1989-01-01

In Escherichia coli, the SOS response and two 3-methyladenine DNA glycosylases (TagI and TagII) are required for repair of DNA damaged by alkylating agents such as methyl methanesulfonate (MMS). Mutations of the recA gene eliminate the SOS response. TagI and TagII are encoded by the tag and alkA genes, respectively. A gene (rpr) encoding 3-methyladenine DNA glycosylase activity was isolated from the Gram-negative bacterium Serratia marcescens. The gene, localized to a 1.5-kilobase pair SmaI-HindIII restriction fragment, was cloned into plasmid pUC18. The clone complemented E. coli tag alkA and recA mutations for MMS resistance. The rpr gene did not, however, complement recA mutations for resistance to ultraviolet light or the ability to perform homologous recombination reactions, nor did it complement E. coli ada or alkB mutations. Two proteins of molecular weights 42,000 and 16,000 were produced from the rpr locus. Analysis of deletion and insertion mutants of rpr suggested that the 42kD molecule is the active protein. The 16kD protein may either be a breakdown product of the 42kD species or may be encoded by another gene overlapping the reading frame of the rpr gene. Biochemical assays showed that the rpr gene product (Rpr) possesses 3-methyladenine DNA glycosylase activity

Chromosomal damage and polymorphisms of DNA repair genes XRCC1 and XRCC3 in workers exposed to chromium

Czech Academy of Sciences Publication Activity Database

Halasová, E.; Mataková, T.; Mušák, L.; Poláková, Veronika; Vodička, Pavel

2008-01-01

Roč. 29, č. 5 (2008), s. 658-662 ISSN 0172-780X Institutional research plan: CEZ:AV0Z50390703 Keywords : Chromosomal aberrations * Polymorphisms * Repair genes Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.359, year: 2008

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

Directory of Open Access Journals (Sweden)

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.

Frequency of intrachromosomal homologous recombination induced by UV radiation in normally repairing and excision repair-deficient human cells

International Nuclear Information System (INIS)

Tsujimura, T.; Maher, V.M.; McCormick, J.J.; Godwin, A.R.; Liskay, R.M.

1990-01-01

To investigate the role of DNA damage and nucleotide excision repair in intrachromosomal homologous recombination, a plasmid containing duplicated copies of the gene coding for hygromycin resistance was introduced into the genome of a repair-proficient human cell line, KMST-6, and two repair-deficient lines, XP2OS(SV) from xeroderma pigmentosum complementation group A and XP2YO(SV) from complementation group F. Neither hygromycin-resistance gene codes for a functional enzyme because each contains an insertion/deletion mutation at a unique site, but recombination between the two defective genes can yield hygromycin-resistant cells. The rates of spontaneous recombination in normal and xeroderma pigmentosum cell strains containing the recombination substrate were found to be similar. The frequency of UV-induced recombination was determined for three of these cell strains. At low doses, the group A cell strain and the group F cell strain showed a significant increase in frequency of recombinants. The repair-proficient cell strain required 10-to 20-fold higher doses of UV to exhibit comparable increases in frequency of recombinants. These results suggest that unexcised DNA damage, rather than the excision repair process per se, stimulates such recombination

Use of Drosophila to study DNA repair

International Nuclear Information System (INIS)

Boyd, J.B.; Harris, P.V.; Sakaguchi, K.

1988-01-01

This paper discusses Drosophila, the premier metazoan organism for analyzing many fundamental features of eukaryotic gene regulation. The authors present adaptations of several approaches for studying DNA repair to an analysis of repair-defective mutants in Drosophila. A current understanding of Drosophila DNA repair is described

RTEL1 contributes to DNA replication and repair and telomere maintenance.

Science.gov (United States)

Uringa, Evert-Jan; Lisaingo, Kathleen; Pickett, Hilda A; Brind'Amour, Julie; Rohde, Jan-Hendrik; Zelensky, Alex; Essers, Jeroen; Lansdorp, Peter M

2012-07-01

Telomere maintenance and DNA repair are important processes that protect the genome against instability. mRtel1, an essential helicase, is a dominant factor setting telomere length in mice. In addition, mRtel1 is involved in DNA double-strand break repair. The role of mRtel1 in telomere maintenance and genome stability is poorly understood. Therefore we used mRtel1-deficient mouse embryonic stem cells to examine the function of mRtel1 in replication, DNA repair, recombination, and telomere maintenance. mRtel1-deficient mouse embryonic stem cells showed sensitivity to a range of DNA-damaging agents, highlighting its role in replication and genome maintenance. Deletion of mRtel1 increased the frequency of sister chromatid exchange events and suppressed gene replacement, demonstrating the involvement of the protein in homologous recombination. mRtel1 localized transiently at telomeres and is needed for efficient telomere replication. Of interest, in the absence of mRtel1, telomeres in embryonic stem cells appeared relatively stable in length, suggesting that mRtel1 is required to allow extension by telomerase. We propose that mRtel1 is a key protein for DNA replication, recombination, and repair and efficient elongation of telomeres by telomerase.

Cloning and Characterizing Genes Involved in Monoterpene Induced Mammary Tumor Regression.

Science.gov (United States)

1996-10-01

AD GRANT NUMBER DAMDI7-94-J-4041 TITLE: Cloning and Characterizing Genes Involved in Monoterpene Induced Mammary Tumor Regression PRINCIPAL...October 1996 Annual (1 Sep 95 - 31 Aug 96) 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Cloning and Characterizing Genes Involved in Monoterpene Induced... Monoterpene -induced/repressed genes were identified in regressing rat mammary carcinomas treated with dietary limonene using a newly developed method

[Constitutional mismatch repair deficiency syndrome

NARCIS (Netherlands)

Jongmans, M.C.J.; Gidding, C.E.M.; Loeffen, J.; Wesseling, P.; Mensenkamp, A.; Hoogerbrugge, N.

2015-01-01

BACKGROUND: Constitutional mismatch repair deficiency (CMMR-D) syndrome is characterised by a significantly increased risk for developing cancer in childhood. It arises when both parents have a mutation in the same mismatch repair gene and pass it on to their child. CASE DESCRIPTION: An 8-year-old

Identification of the DNA repair defects in a case of Dubowitz syndrome.

Directory of Open Access Journals (Sweden)

Jingyin Yue

Full Text Available Dubowitz Syndrome is an autosomal recessive disorder with a unique set of clinical features including microcephaly and susceptibility to tumor formation. Although more than 140 cases of Dubowitz syndrome have been reported since 1965, the genetic defects of this disease has not been identified. In this study, we systematically analyzed the DNA damage response and repair capability of fibroblasts established from a Dubowitz Syndrome patient. Dubowitz syndrome fibroblasts are hypersensitive to ionizing radiation, bleomycin, and doxorubicin. However, they have relatively normal sensitivities to mitomycin-C, cisplatin, and camptothecin. Dubowitz syndrome fibroblasts also have normal DNA damage signaling and cell cycle checkpoint activations after DNA damage. These data implicate a defect in repair of DNA double strand break (DSB likely due to defective non-homologous end joining (NHEJ. We further sequenced several genes involved in NHEJ, and identified a pair of novel compound mutations in the DNA Ligase IV gene. Furthermore, expression of wild type DNA ligase IV completely complement the DNA repair defects in Dubowitz syndrome fibroblasts, suggesting that the DNA ligase IV mutation is solely responsible for the DNA repair defects. These data suggests that at least subset of Dubowitz syndrome can be attributed to DNA ligase IV mutations.

Homologous recombination and non-homologous end-joining repair pathways in bovine embryos with different developmental competence

Energy Technology Data Exchange (ETDEWEB)

Henrique Barreta, Marcos [Universidade Federal de Santa Catarina, Campus Universitario de Curitibanos, Curitibanos, SC (Brazil); Laboratorio de Biotecnologia e Reproducao Animal-BioRep, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Garziera Gasperin, Bernardo; Braga Rissi, Vitor; Cesaro, Matheus Pedrotti de [Laboratorio de Biotecnologia e Reproducao Animal-BioRep, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Ferreira, Rogerio [Centro de Educacao Superior do Oeste-Universidade do Estado de Santa Catarina, Chapeco, SC (Brazil); Oliveira, Joao Francisco de; Goncalves, Paulo Bayard Dias [Laboratorio de Biotecnologia e Reproducao Animal-BioRep, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil); Bordignon, Vilceu, E-mail: vilceu.bordignon@mcgill.ca [Department of Animal Science, McGill University, Ste-Anne-De-Bellevue, QC (Canada)

2012-10-01

This study investigated the expression of genes controlling homologous recombination (HR), and non-homologous end-joining (NHEJ) DNA-repair pathways in bovine embryos of different developmental potential. It also evaluated whether bovine embryos can respond to DNA double-strand breaks (DSBs) induced with ultraviolet irradiation by regulating expression of genes involved in HR and NHEJ repair pathways. Embryos with high, intermediate or low developmental competence were selected based on the cleavage time after in vitro insemination and were removed from in vitro culture before (36 h), during (72 h) and after (96 h) the expected period of embryonic genome activation. All studied genes were expressed before, during and after the genome activation period regardless the developmental competence of the embryos. Higher mRNA expression of 53BP1 and RAD52 was found before genome activation in embryos with low developmental competence. Expression of 53BP1, RAD51 and KU70 was downregulated at 72 h and upregulated at 168 h post-insemination in response to DSBs induced by ultraviolet irradiation. In conclusion, important genes controlling HR and NHEJ DNA-repair pathways are expressed in bovine embryos, however genes participating in these pathways are only regulated after the period of embryo genome activation in response to ultraviolet-induced DSBs.

Homologous recombination and non-homologous end-joining repair pathways in bovine embryos with different developmental competence

International Nuclear Information System (INIS)

Henrique Barreta, Marcos; Garziera Gasperin, Bernardo; Braga Rissi, Vitor; Cesaro, Matheus Pedrotti de; Ferreira, Rogério; Oliveira, João Francisco de; Gonçalves, Paulo Bayard Dias; Bordignon, Vilceu

2012-01-01

This study investigated the expression of genes controlling homologous recombination (HR), and non-homologous end-joining (NHEJ) DNA-repair pathways in bovine embryos of different developmental potential. It also evaluated whether bovine embryos can respond to DNA double-strand breaks (DSBs) induced with ultraviolet irradiation by regulating expression of genes involved in HR and NHEJ repair pathways. Embryos with high, intermediate or low developmental competence were selected based on the cleavage time after in vitro insemination and were removed from in vitro culture before (36 h), during (72 h) and after (96 h) the expected period of embryonic genome activation. All studied genes were expressed before, during and after the genome activation period regardless the developmental competence of the embryos. Higher mRNA expression of 53BP1 and RAD52 was found before genome activation in embryos with low developmental competence. Expression of 53BP1, RAD51 and KU70 was downregulated at 72 h and upregulated at 168 h post-insemination in response to DSBs induced by ultraviolet irradiation. In conclusion, important genes controlling HR and NHEJ DNA-repair pathways are expressed in bovine embryos, however genes participating in these pathways are only regulated after the period of embryo genome activation in response to ultraviolet-induced DSBs.

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

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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.

Unique DNA repair gene variations and potential associations with the primary antibody deficiency syndromes IgAD and CVID.

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Steven M Offer

Full Text Available BACKGROUND: Despite considerable effort, the genetic factors responsible for >90% of the antibody deficiency syndromes IgAD and CVID remain elusive. To produce a functionally diverse antibody repertoire B lymphocytes undergo class switch recombination. This process is initiated by AID-catalyzed deamination of cytidine to uridine in switch region DNA. Subsequently, these residues are recognized by the uracil excision enzyme UNG2 or the mismatch repair proteins MutSalpha (MSH2/MSH6 and MutLalpha (PMS2/MLH1. Further processing by ubiquitous DNA repair factors is thought to introduce DNA breaks, ultimately leading to class switch recombination and expression of a different antibody isotype. METHODOLOGY/PRINCIPAL FINDINGS: Defects in AID and UNG2 have been shown to result in the primary immunodeficiency hyper-IgM syndrome, leading us to hypothesize that additional, potentially more subtle, DNA repair gene variations may underlie the clinically related antibody deficiencies syndromes IgAD and CVID. In a survey of twenty-seven candidate DNA metabolism genes, markers in MSH2, RAD50, and RAD52 were associated with IgAD/CVID, prompting further investigation into these pathways. Resequencing identified four rare, non-synonymous alleles associated with IgAD/CVID, two in MLH1, one in RAD50, and one in NBS1. One IgAD patient carried heterozygous non-synonymous mutations in MLH1, MSH2, and NBS1. Functional studies revealed that one of the identified mutations, a premature RAD50 stop codon (Q372X, confers increased sensitivity to ionizing radiation. CONCLUSIONS: Our results are consistent with a class switch recombination model in which AID-catalyzed uridines are processed by multiple DNA repair pathways. Genetic defects in these DNA repair pathways may contribute to IgAD and CVID.

Genes Involved in DNA Double-Strand Break Repair: Implications for Breast Cancer.

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1996-10-01

dependent kinase (p350) as a cietv of America Scholar. W.K.R. is a Howard Hughes Medical Insti- candidate gene for the murine SCID defect. Science 267:1178...Howard Hughes Medical Institute (W. K. R.). 26), are rescued by transfection of Ku86 cDNA (27, 28), and have 2 To whom requests for reprints should be... Jackman . J.. Wang. M. G., McBride. 0. W., and Fornace, 40. Papathanasiou. M. A.. Kerr, N. C. K., Robbins, J. H., McBride. 0. W., Alamo, I., A. J

Genes involved in Beauveria bassiana infection to Galleria mellonella.

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Chen, Anhui; Wang, Yulong; Shao, Ying; Zhou, Qiumei; Chen, Shanglong; Wu, Yonghua; Chen, Hongwei; Liu, Enqi

2018-05-01

The ascomycete fungus Beauveria bassiana is a natural pathogen of hundreds of insect species and is commercially produced as an environmentally friendly mycoinsecticide. Many genes involved in fungal insecticide infection have been identified but few have been further explored. In this study, we constructed three transcriptomes of B. bassiana at 24, 48 and 72 h post infection of insect pests (BbI) or control (BbC). There were 3148, 3613 and 4922 genes differentially expressed at 24, 48 and 72 h post BbI/BbC infection, respectively. A large number of genes and pathways involved in infection were identified. To further analyze those genes, expression patterns across different infection stages (0, 12, 24, 36, 48, 60, 72 and 84 h) were studied using quantitative RT-PCR. This analysis showed that the infection-related genes could be divided into four patterns: highly expressed throughout the whole infection process (thioredoxin 1); highly expressed during early stages of infection but lowly expressed after the insect death (adhesin protein Mad1); lowly expressed during early infection but highly expressed after insect death (cation transporter, OpS13); or lowly expressed across the entire infection process (catalase protein). The data provide novel insights into the insect-pathogen interaction and help to uncover the molecular mechanisms involved in fungal infection of insect pests.

Screening of the DNA mismatch repair genes MLH1, MSH2 and MSH6 in a Greek cohort of Lynch syndrome suspected families

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Thodi, Georgia; Fountzilas, George; Yannoukakos, Drakoulis; Fostira, Florentia; Sandaltzopoulos, Raphael; Nasioulas, George; Grivas, Anastasios; Boukovinas, Ioannis; Mylonaki, Maria; Panopoulos, Christos; Magic, Mirjana Brankovic

2010-01-01

Germline mutations in the DNA mismatch repair genes predispose to Lynch syndrome, thus conferring a high relative risk of colorectal and endometrial cancer. The MLH1, MSH2 and MSH6 mutational spectrum reported so far involves minor alterations scattered throughout their coding regions as well as large genomic rearrangements. Therefore, a combination of complete sequencing and a specialized technique for the detection of genomic rearrangements should be conducted during a proper DNA-testing procedure. Our main goal was to successfully identify Lynch syndrome families and determine the spectrum of MLH1, MSH2 and MSH6 mutations in Greek Lynch families in order to develop an efficient screening protocol for the Greek colorectal cancer patients' cohort. Forty-two samples from twenty-four families, out of which twenty two of Greek, one of Cypriot and one of Serbian origin, were screened for the presence of germline mutations in the major mismatch repair genes through direct sequencing and MLPA. Families were selected upon Amsterdam criteria or revised Bethesda guidelines. Ten deleterious alterations were detected in twelve out of the twenty-four families subjected to genetic testing, thus our detection rate is 50%. Four of the pathogenic point mutations, namely two nonsense, one missense and one splice site change, are novel, whereas the detected genomic deletion encompassing exon 6 of the MLH1 gene has been described repeatedly in the LOVD database. The average age of onset for the development of both colorectal and endometrial cancer among mutation positive families is 43.2 years. The mutational spectrum of the MMR genes investigated as it has been shaped by our analysis is quite heterogeneous without any strong indication for the presence of a founder effect

A comprehensive candidate gene approach identifies genetic variation associated with osteosarcoma

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Mirabello, Lisa; Grotmol, Tom; Douglass, Chester; Hayes, Richard B; Hoover, Robert N; Savage, Sharon A; Yu, Kai; Berndt, Sonja I; Burdett, Laurie; Wang, Zhaoming; Chowdhury, Salma; Teshome, Kedest; Uzoka, Arinze; Hutchinson, Amy

2011-01-01

Osteosarcoma (OS) is a bone malignancy which occurs primarily in adolescents. Since it occurs during a period of rapid growth, genes important in bone formation and growth are plausible modifiers of risk. Genes involved in DNA repair and ribosomal function may contribute to OS pathogenesis, because they maintain the integrity of critical cellular processes. We evaluated these hypotheses in an OS association study of genes from growth/hormone, bone formation, DNA repair, and ribosomal pathways. We evaluated 4836 tag-SNPs across 255 candidate genes in 96 OS cases and 1426 controls. Logistic regression models were used to estimate the odds ratios (OR) and 95% confidence intervals (CI). Twelve SNPs in growth or DNA repair genes were significantly associated with OS after Bonferroni correction. Four SNPs in the DNA repair gene FANCM (ORs 1.9-2.0, P = 0.003-0.004) and 2 SNPs downstream of the growth hormone gene GH1 (OR 1.6, P = 0.002; OR 0.5, P = 0.0009) were significantly associated with OS. One SNP in the region of each of the following genes was significant: MDM2, MPG, FGF2, FGFR3, GNRH2, and IGF1. Our results suggest that several SNPs in biologically plausible pathways are associated with OS. Larger studies are required to confirm our findings

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

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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.

A link between double-strand break-related repair and V(D)J recombination: the scid mutation

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Hendrickson, E.A.; Qin, X.Q.; Bump, E.A.; Schatz, D.G.; Oettinger, M.; Weaver, D.T.

1991-01-01

We show here that mammalian site-specific recombination and DNA-repair pathways share a common factor. The effects of DNA-damaging agents on cell lines derived from mice homozygous for the scid (severe combined immune deficiency) mutation were studied. Surprisingly, all scid cell lines exhibited a profound hypersensitivity to DNA-damaging agents that caused double-strand breaks (x-irradiation and bleomycin) but not to other chemicals that caused single-strand breaks or cross-links. Neutral filter elution assays demonstrated that the x-irradiation hypersensitivity could be correlated with a deficiency in repairing double-strand breaks. These data suggest that the scid gene product is involved in two pathways: DNA repair of random double-strand breaks and the site-specific and lymphoid-restricted variable-(diversity)-joining [V(D)J] DNA rearrangement process. We propose that the scid gene product performs a similar function in both pathways and may be a ubiquitous protein

Differential expression of SOS genes in an E. coli mutant producing unstable lexA protein enhances excision repair but inhibits mutagenesis

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Peterson, K.R.; Ganesan, A.K.; Mount, D.W.; Stanford Univ., CA)

1986-01-01

The SOS response is displayed following treatments which damage DNA or inhibit DNA replication. Two associated activities include enhanced capacity for DNA repair resulting from derepression of the recA, uvrA, uvrB and uvrD genes and increased mutagenesis due to derepression of recA, umuC and umuD. These changes are the consequence of the derepression of at least seventeen unlinked operons negatively regulated by LexA repressor. Following treatments that induce the SOS response, a signal molecule interacts with RecA protein, converting it to an activated form. Activated RecA protein facilitates the proteolytic cleavage of LexA repressor, which results in derepression of the regulon. The cell then enters a new physiological state during which time DNA repair processes are augmented. The lexA41 mutant of E. coli is a uv-resistant derivative of another mutant, lexA3, which produces a repressor that is not cleaved following inducing treatments. The resultant protein is unstable. Lac operon fusions to most of the genes in the SOS regulon were used to show that the various damage-inducible genes were derepressed to different extents. uvrA, B, and D were almost fully derepressed. Consistent with this finding, the rate of removal of T4 endonuclease V-sensitive sites was more rapid in the uv-irradiated lexA41 mutant than in normal cells, suggesting a more active excision repair system. We propose that the instability of the LexA41 protein reduces the intracellular concentration of repressor to a level that allows a high level of excision repair. The additional observation that SOS mutagenesis was only weakly induced in a lexA41 uvrA - mutant implies that the mutant protein partially represses one or more genes whose products promote SOS mutagenesis. 17 refs., 4 figs., 1 tab

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

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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

Predictive models for mutations in mismatch repair genes: implication for genetic counseling in developing countries

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Monteiro Santos Erika

2012-02-01

Full Text Available Abstract Background Lynch syndrome (LS is the most common form of inherited predisposition to colorectal cancer (CRC, accounting for 2-5% of all CRC. LS is an autosomal dominant disease characterized by mutations in the mismatch repair genes mutL homolog 1 (MLH1, mutS homolog 2 (MSH2, postmeiotic segregation increased 1 (PMS1, post-meiotic segregation increased 2 (PMS2 and mutS homolog 6 (MSH6. Mutation risk prediction models can be incorporated into clinical practice, facilitating the decision-making process and identifying individuals for molecular investigation. This is extremely important in countries with limited economic resources. This study aims to evaluate sensitivity and specificity of five predictive models for germline mutations in repair genes in a sample of individuals with suspected Lynch syndrome. Methods Blood samples from 88 patients were analyzed through sequencing MLH1, MSH2 and MSH6 genes. The probability of detecting a mutation was calculated using the PREMM, Barnetson, MMRpro, Wijnen and Myriad models. To evaluate the sensitivity and specificity of the models, receiver operating characteristic curves were constructed. Results Of the 88 patients included in this analysis, 31 mutations were identified: 16 were found in the MSH2 gene, 15 in the MLH1 gene and no pathogenic mutations were identified in the MSH6 gene. It was observed that the AUC for the PREMM (0.846, Barnetson (0.850, MMRpro (0.821 and Wijnen (0.807 models did not present significant statistical difference. The Myriad model presented lower AUC (0.704 than the four other models evaluated. Considering thresholds of ≥ 5%, the models sensitivity varied between 1 (Myriad and 0.87 (Wijnen and specificity ranged from 0 (Myriad to 0.38 (Barnetson. Conclusions The Barnetson, PREMM, MMRpro and Wijnen models present similar AUC. The AUC of the Myriad model is statistically inferior to the four other models.

Expression profiling identifies genes involved in emphysema severity

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Bowman Rayleen V

2009-09-01

Full Text Available Abstract Chronic obstructive pulmonary disease (COPD is a major public health problem. The aim of this study was to identify genes involved in emphysema severity in COPD patients. Gene expression profiling was performed on total RNA extracted from non-tumor lung tissue from 30 smokers with emphysema. Class comparison analysis based on gas transfer measurement was performed to identify differentially expressed genes. Genes were then selected for technical validation by quantitative reverse transcriptase-PCR (qRT-PCR if also represented on microarray platforms used in previously published emphysema studies. Genes technically validated advanced to tests of biological replication by qRT-PCR using an independent test set of 62 lung samples. Class comparison identified 98 differentially expressed genes (p p Gene expression profiling of lung from emphysema patients identified seven candidate genes associated with emphysema severity including COL6A3, SERPINF1, ZNHIT6, NEDD4, CDKN2A, NRN1 and GSTM3.

The role of the Fanconi anemia pathway in DNA repair and maintenance of genome stability

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Aleksandra M. Koczorowska

2014-05-01

Full Text Available The Fanconi anemia (FA pathway is one of the DNA repair systems involved in removal of DNA crosslinks. Proteins which belong to this pathway are crucial to the protection of genetic information, whereas disturbances in their function have serious implications for the whole organism. Biallelic mutations in FA genes are the cause of Fanconi anemia – a genetic disease which manifests itself through numerous congenital abnormalities, chromosomal instability and increased predisposition to cancer. The FA pathway is composed of fifteen proteins. Eight of them, in the presence of DNA interstrand crosslinks (ICLs, form a nuclear core complex responsible for monoubiquitination of FANCD2 and FANCI, which is a key step of ICL repair. FA proteins which are not involved in the monoubiquitination step participate in repair of DNA double strand breaks via homologous recombination. Some of the FA proteins, besides having a direct role in the repair of DNA damage, are engaged in replication, cell cycle control and mitosis. The unperturbed course of those processes determines the maintenance of genome stability.

Changes in the Coding and Non-coding Transcriptome and DNA Methylome that Define the Schwann Cell Repair Phenotype after Nerve Injury.

Science.gov (United States)

Arthur-Farraj, Peter J; Morgan, Claire C; Adamowicz, Martyna; Gomez-Sanchez, Jose A; Fazal, Shaline V; Beucher, Anthony; Razzaghi, Bonnie; Mirsky, Rhona; Jessen, Kristjan R; Aitman, Timothy J

2017-09-12

Repair Schwann cells play a critical role in orchestrating nerve repair after injury, but the cellular and molecular processes that generate them are poorly understood. Here, we perform a combined whole-genome, coding and non-coding RNA and CpG methylation study following nerve injury. We show that genes involved in the epithelial-mesenchymal transition are enriched in repair cells, and we identify several long non-coding RNAs in Schwann cells. We demonstrate that the AP-1 transcription factor C-JUN regulates the expression of certain micro RNAs in repair Schwann cells, in particular miR-21 and miR-34. Surprisingly, unlike during development, changes in CpG methylation are limited in injury, restricted to specific locations, such as enhancer regions of Schwann cell-specific genes (e.g., Nedd4l), and close to local enrichment of AP-1 motifs. These genetic and epigenomic changes broaden our mechanistic understanding of the formation of repair Schwann cell during peripheral nervous system tissue repair. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

DNA methylation changes in genes frequently mutated in sporadic colorectal cancer and in the DNA repair and Wnt/β-catenin signaling pathway genes

Czech Academy of Sciences Publication Activity Database

Farkas, S. A.; Vymetálková, Veronika; Vodičková, Ludmila; Vodička, Pavel; Torbjörn, K. N.

2014-01-01

Roč. 6, č. 2 (2014), s. 179-191 ISSN 1750-1911 R&D Projects: GA ČR GPP304/11/P715; GA ČR(CZ) GAP304/12/1585; GA MZd NT14329 Institutional support: RVO:68378041 Keywords : CpG * DNA repair genes * sporadic colorectal cancer Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.649, year: 2014

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

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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.

Functional role of DNA mismatch repair gene PMS2 in prostate cancer cells.

Science.gov (United States)

Fukuhara, Shinichiro; Chang, Inik; Mitsui, Yozo; Chiyomaru, Takeshi; Yamamura, Soichiro; Majid, Shahana; Saini, Sharanjot; Deng, Guoren; Gill, Ankurpreet; Wong, Darryn K; Shiina, Hiroaki; Nonomura, Norio; Lau, Yun-Fai C; Dahiya, Rajvir; Tanaka, Yuichiro

2015-06-30

DNA mismatch repair (MMR) enzymes act as proofreading complexes that maintains genomic integrity and MMR-deficient cells show an increased mutation rate. MMR has also been shown to influence cell signaling and the regulation of tumor development. MMR consists of various genes and includes post-meiotic segregation (PMS) 2 which is a vital component of mutL-alpha. In prostate, the functional role of this gene has never been reported and in this study, our aim was to investigate the effect of PMS2 on growth properties of prostate cancer (PCa) cells. Previous studies have shown PMS2 to be deficient in DU145 cells and this lack of expression was confirmed by Western blotting whereas normal prostatic PWR-1E and RWPE-1 cells expressed this gene. PMS2 effects on various growth properties of DU145 were then determined by creating stable gene transfectants. Interestingly, PMS2 caused decreased cell proliferation, migration, invasion, and in vivo growth; and increased apoptosis as compared to vector control. We further analyzed genes affected by PMS2 expression and observe the apoptosis-related TMS1 gene to be significantly upregulated whereas anti-apoptotic BCL2A1 was downregulated. These results demonstrate a functional role for PMS2 to protect against PCa progression by enhancing apoptosis of PCa cells.

Mismatch repair genes Mlh1 and Mlh3 modify CAG instability in Huntington's disease mice: genome-wide and candidate approaches.

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Pinto, Ricardo Mouro; Dragileva, Ella; Kirby, Andrew; Lloret, Alejandro; Lopez, Edith; St Claire, Jason; Panigrahi, Gagan B; Hou, Caixia; Holloway, Kim; Gillis, Tammy; Guide, Jolene R; Cohen, Paula E; Li, Guo-Min; Pearson, Christopher E; Daly, Mark J; Wheeler, Vanessa C

2013-10-01

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 that MLH1

Mismatch repair genes Mlh1 and Mlh3 modify CAG instability in Huntington's disease mice: genome-wide and candidate approaches.

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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

Recombinant methods for screening human DNA excision repair proficiency

International Nuclear Information System (INIS)

Athas, W.F.

1988-01-01

A method for measuring DNA excision repair in response to ultraviolet radiation (UV)-induced DNA damage has been developed, validated, and field-tested in cultured human lymphocytes. The methodology is amenable to population-based screening and should facilitate future epidemiologic studies seeking to investigate associations between excision repair proficiency and cancer susceptibility. The impetus for such endeavors derives from the belief that the high incidence of skin cancer in the genetic disorder xeroderma pigmentosum (XP) primarily is a result of the reduced capacity of patients cells to repair UV-induced DNA damage. For assay, UV-irradiated non-replicating recombinant plasmid DNA harboring a chloramphenicol acetyltransferase (CAT) indicator gene is introduced into lymphocytes using DEAE-dextran short-term transfection conditions. Exposure to UV induces transcriptionally-inactivating DNA photoproducts in the plasmid DNA which inactivate CAT gene expression. Excision repair of the damaged CAT gene is monitored indirectly as a function of reactivated CAT enzyme activity following a 40 hour repair/expression incubation period

DNA Repair Defects and Chromosomal Aberrations

Science.gov (United States)

Hada, Megumi; George, K. A.; Huff, J. L.; Pluth, J. M.; Cucinotta, F. A.

2009-01-01

Yields of chromosome aberrations were assessed in cells deficient in DNA doublestrand break (DSB) repair, after exposure to acute or to low-dose-rate (0.018 Gy/hr) gamma rays or acute high LET iron nuclei. We studied several cell lines including fibroblasts deficient in ATM (ataxia telangiectasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. Chromosomes were analyzed using the fluorescence in situ hybridization (FISH) chromosome painting method in cells at the first division post irradiation, and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma irradiation induced greater yields of both simple and complex exchanges in the DSB repair-defective cells than in the normal cells. The quadratic dose-response terms for both simple and complex chromosome exchanges were significantly higher for the ATM- and NBS-deficient lines than for normal fibroblasts. However, in the NBS cells the linear dose-response term was significantly higher only for simple exchanges. The large increases in the quadratic dose-response terms in these repair-defective cell lines points the importance of the functions of ATM and NBS in chromatin modifications to facilitate correct DSB repair and minimize the formation of aberrations. The differences found between ATM- and NBS-deficient cells at low doses suggest that important questions should with regard to applying observations of radiation sensitivity at high dose to low-dose exposures. For aberrations induced by iron nuclei, regression models preferred purely linear dose responses for simple exchanges and quadratic dose responses for complex exchanges. Relative biological effectiveness (RBE) factors of all of

DNA Repair and Ethnic Differences in Prostate Cancer Risk

National Research Council Canada - National Science Library

Goldman, Radoslav

2008-01-01

.... To evaluate this hypothesis we quantify DNA repair capacity in blood cells using comet assay and evaluate how this repair capacity is related to genetic variants in OGG1 and XRCC1 DNA repair genes...

DNA Repair and Ethnic Differences in Prostate Cancer Risk

National Research Council Canada - National Science Library

Goldman, Radoslav

2007-01-01

.... To evaluate this hypothesis we quantify DNA repair capacity in blood cells using comet assay and evaluate how this repair capacity is related to genetic variants in OGG1 and XRCC1 DNA repair genes...

DNA Repair and Ethnic Differences in Prostate Cancer Risk

National Research Council Canada - National Science Library

Goldman, Radoslav

2006-01-01

.... To evaluate this hypothesis, we quantify DNA repair capacity in blood cells using comet assay and evaluate how this repair capacity is related to genetic variants in OGG1 and XRCC1 DNA repair genes...

Plant Genes Involved in Symbiotic Sinal Perception/Signal Transduction

DEFF Research Database (Denmark)

Binder, A; Soyano, T; Hayashi, H

2014-01-01

to nodule primordia formation, and the infection thread initiation in the root hairs guiding bacteria towards dividing cortical cells. This chapter focuses on the plant genes involved in the recognition of the symbiotic signal produced by rhizobia, and the downstream genes, which are part of a complex...... symbiotic signalling pathway that leads to the generation of calcium spiking in the nuclear regions and activation of transcription factors controlling symbiotic genes induction...

p53 downregulates the Fanconi anaemia DNA repair pathway.

Science.gov (United States)

Jaber, Sara; Toufektchan, Eléonore; Lejour, Vincent; Bardot, Boris; Toledo, Franck

2016-04-01

Germline mutations affecting telomere maintenance or DNA repair may, respectively, cause dyskeratosis congenita or Fanconi anaemia, two clinically related bone marrow failure syndromes. Mice expressing p53(Δ31), a mutant p53 lacking the C terminus, model dyskeratosis congenita. Accordingly, the increased p53 activity in p53(Δ31/Δ31) fibroblasts correlated with a decreased expression of 4 genes implicated in telomere syndromes. Here we show that these cells exhibit decreased mRNA levels for additional genes contributing to telomere metabolism, but also, surprisingly, for 12 genes mutated in Fanconi anaemia. Furthermore, p53(Δ31/Δ31) fibroblasts exhibit a reduced capacity to repair DNA interstrand crosslinks, a typical feature of Fanconi anaemia cells. Importantly, the p53-dependent downregulation of Fanc genes is largely conserved in human cells. Defective DNA repair is known to activate p53, but our results indicate that, conversely, an increased p53 activity may attenuate the Fanconi anaemia DNA repair pathway, defining a positive regulatory feedback loop.

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 pMLH1, MSH2 and ATM 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.

Reduction of spontaneous somatic mutation frequency by a low-dose X irradiation of Drosophila larvae and possible involvement of DNA single-strand damage repair.

Science.gov (United States)

Koana, Takao; Takahashi, Takashi; Tsujimura, Hidenobu

2012-03-01

The third instar larvae of Drosophila were irradiated with X rays, and the somatic mutation frequency in their wings was measured after their eclosion. In the flies with normal DNA repair and apoptosis functions, 0.2 Gy irradiation at 0.05 Gy/min reduced the frequency of the so-called small spot (mutant cell clone with reduced reproductive activity) compared with that in the sham-irradiated flies. When apoptosis was suppressed using the baculovirus p35 gene, the small spot frequency increased four times in the sham-irradiated control group, but the reduction by the 0.2-Gy irradiation was still evident. In a non-homologous end joining-deficient mutant, the small spot frequency was also reduced by 0.2 Gy radiation. In a mutant deficient in single-strand break repair, no reduction in the small spot frequency by 0.2 Gy radiation was observed, and the small spot frequency increased with the radiation dose. Large spot (mutant cell clone with normal reproductive activity) frequency was not affected by suppression of apoptosis and increased monotonically with radiation dose in wild-type larvae and in mutants for single- or double-strand break repair. It is hypothesized that some of the small spots resulted from single-strand damage and, in wild-type larvae, 0.2 Gy radiation activated the normal single-strand break repair gene, which reduced the background somatic mutation frequency.

Repair by genetic recombination in bacteria: overview

International Nuclear Information System (INIS)

Howard-Flanders, P.

1975-01-01

DNA molecules that have been damaged in both strands at the same level are not subject to repair by excision but instead can be repaired through recombination with homologous molecules. Examples of two-strand damage include postreplication gaps opposite pyrimidine dimers, two-strand breaks produced by x-rays, and chemically induced interstrand cross-links. In ultraviolet-irradiated bacteria, and newly synthesized DNA is of length equal to the interdimer spacing. With continued incubation, this low-molecular-weight DNA is joined into high-molecular-weight chains (postreplication repair), a process associated with sister exchanges in bacteria. Recombination is initiated by pyrimidine dimers opposite postreplication gaps and by interstrand cross-links that have been cut by excision enzymes. The free ends at the resulting gaps presumably initiate the exchanges. Postreplication repair in Escherichia coli occurs in recB - and recC - but is greatly slowed in recF - mutants. RecB and recC are the structural genes for exonuclease V, which digests two-stranded DNA by releasing oligonucleotides first from one strand and then from the other. The postreplication sister exchanges in ultraviolet-irradiated bacteria result in the distribution of pyrimidine dimers between parental and daughter strands, indicating that long exchanges involving both strands of each duplex occur. The R1 restriction endonuclease from E. coli has been used to cut the DNA of a bacterial drug-resistance transfer factor with one nuclease-sensitive site, and also DNA from the frog Xenopus enriched for ribosomal 18S and 28S genes. The fragments were annealed with the cut plasmid DNA and ligated, producing a new larger plasmid carrying the eukaryotic rDNA and able to infect and replicate in E. coli

Gene Expression Profiling in the Injured Spinal Cord of Trachemys scripta elegans: An Amniote with Self-Repair Capabilities.

Science.gov (United States)

Valentin-Kahan, Adrián; García-Tejedor, Gabriela B; Robello, Carlos; Trujillo-Cenóz, Omar; Russo, Raúl E; Alvarez-Valin, Fernando

2017-01-01

Slider turtles are the only known amniotes with self-repair mechanisms of the spinal cord that lead to substantial functional recovery. Their strategic phylogenetic position makes them a relevant model to investigate the peculiar genetic programs that allow anatomical reconnection in some vertebrate groups but are absent in others. Here, we analyze the gene expression profile of the response to spinal cord injury (SCI) in the turtle Trachemys scripta elegans . We found that this response comprises more than 1000 genes affecting diverse functions: reaction to ischemic insult, extracellular matrix re-organization, cell proliferation and death, immune response, and inflammation. Genes related to synapses and cholesterol biosynthesis are down-regulated. The analysis of the evolutionary distribution of these genes shows that almost all are present in most vertebrates. Additionally, we failed to find genes that were exclusive of regenerating taxa. The comparison of expression patterns among species shows that the response to SCI in the turtle is more similar to that of mice and non-regenerative Xenopus than to Xenopus during its regenerative stage. This observation, along with the lack of conserved "regeneration genes" and the current accepted phylogenetic placement of turtles (sister group of crocodilians and birds), indicates that the ability of spinal cord self-repair of turtles does not represent the retention of an ancestral vertebrate character. Instead, our results suggest that turtles developed this capability from a non-regenerative ancestor (i.e., a lineage specific innovation) that was achieved by re-organizing gene expression patterns on an essentially non-regenerative genetic background. Among the genes activated by SCI exclusively in turtles, those related to anoxia tolerance, extracellular matrix remodeling, and axonal regrowth are good candidates to underlie functional recovery.

Chlamydomonas chloroplasts can use short dispersed repeats and multiple pathways to repair a double-strand break in the genome.

Science.gov (United States)

Odom, Obed W; Baek, Kwang-Hyun; Dani, Radhika N; Herrin, David L

2008-03-01

Certain group I introns insert into intronless DNA via an endonuclease that creates a double-strand break (DSB). There are two models for intron homing in phage: synthesis-dependent strand annealing (SDSA) and double-strand break repair (DSBR). The Cr.psbA4 intron homes efficiently from a plasmid into the chloroplast psbA gene in Chlamydomonas, but little is known about the mechanism. Analysis of co-transformants selected using a spectinomycin-resistant 16S gene (16S(spec)) provided evidence for both pathways. We also examined the consequences of the donor DNA having only one-sided or no homology with the psbA gene. When there was no homology with the donor DNA, deletions of up to 5 kb involving direct repeats that flank the psbA gene were obtained. Remarkably, repeats as short as 15 bp were used for this repair, which is consistent with the single-strand annealing (SSA) pathway. When the donor had one-sided homology, the DSB in most co-transformants was repaired using two DNAs, the donor and the 16S(spec) plasmid, which, coincidentally, contained a region that is repeated upstream of psbA. DSB repair using two separate DNAs provides further evidence for the SDSA pathway. These data show that the chloroplast can repair a DSB using short dispersed repeats located proximally, distally, or even on separate molecules relative to the DSB. They also provide a rationale for the extensive repertoire of repeated sequences in this genome.

Micrococcus luteus correndonucleases. III. Evidence for involvement in repair in vivo of two endonucleases specific for DNA containing pyrimidine dimers

International Nuclear Information System (INIS)

Riazuddin, S.; Grossman, L.; Mahler, I.

1977-01-01

Involvement of Py--Py correndonucleases I and II in repair of ultraviolet radiation damage in vivo by Micrococcus luteus has been demonstrated by their absence in the ultraviolet-sensitive mutant DB-7 derived by treatment of the wild type parent with N-methyl-N'-nitro-N-nitrosoguanidine. The necessity for their combined action in DNA repair in M. luteus is shown by: (a) reactivation of ultraviolet-damaged phiX174 RFI DNA in incision-defective hosts after in vivo treatment with both enzymes, (b) correlation between survival after ultraviolet irradiation and the level of the two enzymes, and (c) increased levels of repair synthesis after ultraviolet irradiation of toluenized cells DB-400 with wild type correndonuclease levels when compared with the transformant DB-200 and the mutant DB-7, which lack one or both enzymes

CpG promoter methylation of the ALKBH3 alkylation repair gene in breast cancer.

Science.gov (United States)

Stefansson, Olafur Andri; Hermanowicz, Stefan; van der Horst, Jasper; Hilmarsdottir, Holmfridur; Staszczak, Zuzanna; Jonasson, Jon Gunnlaugur; Tryggvadottir, Laufey; Gudjonsson, Thorkell; Sigurdsson, Stefan

2017-07-05

DNA repair of alkylation damage is defective in various cancers. This occurs through somatically acquired inactivation of the MGMT gene in various cancer types, including breast cancers. In addition to MGMT, the two E. coli AlkB homologs ALKBH2 and ALKBH3 have also been linked to direct reversal of alkylation damage. However, it is currently unknown whether ALKBH2 or ALKBH3 are found inactivated in cancer. Methylome datasets (GSE52865, GSE20713, GSE69914), available through Omnibus, were used to determine whether ALKBH2 or ALKBH3 are found inactivated by CpG promoter methylation. TCGA dataset enabled us to then assess the impact of CpG promoter methylation on mRNA expression for both ALKBH2 and ALKBH3. DNA methylation analysis for the ALKBH3 promoter region was carried out by pyrosequencing (PyroMark Q24) in 265 primary breast tumours and 30 proximal normal breast tissue samples along with 8 breast-derived cell lines. ALKBH3 mRNA and protein expression were analysed in cell lines using RT-PCR and Western blotting, respectively. DNA alkylation damage assay was carried out in cell lines based on immunofluorescence and confocal imaging. Data on clinical parameters and survival outcomes in patients were obtained and assessed in relation to ALKBH3 promoter methylation. The ALKBH3 gene, but not ALKBH2, undergoes CpG promoter methylation and transcriptional silencing in breast cancer. We developed a quantitative alkylation DNA damage assay based on immunofluorescence and confocal imaging revealing higher levels of alkylation damage in association with epigenetic inactivation of the ALKBH3 gene (P = 0.029). In our cohort of 265 primary breast cancer, we found 72 cases showing aberrantly high CpG promoter methylation over the ALKBH3 promoter (27%; 72 out of 265). We further show that increasingly higher degree of ALKBH3 promoter methylation is associated with reduced breast-cancer specific survival times in patients. In this analysis, ALKBH3 promoter methylation at >20

Temporal expression of genes involved in the biosynthesis of ...

African Journals Online (AJOL)

Gibberellins (GAs) are a large family of endogenous plant growth regulators. Bioactive GAs influence nearly all processes during plant growth and development. In the present study, we cloned and identified 10 unique genes that are potentially involved in the biosynthesis of GAs, including one BpGGDP gene, two BpCPS ...

Roles for the yeast RAD18 and RAD52 DNA repair genes in UV mutagenesis.

Science.gov (United States)

Armstrong, J D; Chadee, D N; Kunz, B A

1994-11-01

Experimental evidence indicates that although the Saccharomyces cerevisiae RAD18 and RAD52 genes are not required for nucleotide excision repair, they function in the processing of UV-induced DNA damage in yeast. Conflicting statements regarding the UV mutability of strains deleted for RAD18 prompted us to re-examine the influence of RAD18, and RAD52, on UV mutagenesis. To do so, we characterized mutations induced by UV in SUP4-o, a yeast suppressor tRNA gene. SUP4-o was maintained on a plasmid in isogenic strains that either carried one of two different rad18 deletions (rad18 delta) or had RAD52 disrupted. Both rad18 deletions decreased the frequency of UV-induced SUP4-o mutations to levels close to those for spontaneous mutagenesis in the rad18 delta backgrounds, and prevented a net increase in mutant yield. A detailed analysis of mutations isolated after UV irradiation of one of the rad18 delta strains uncovered little evidence of the specificity features typical for UV mutagenesis in the isogenic repair-proficient (RAD) parent (e.g., predominance of G.C-->A.T transitions). Evidently, UV induction of SUP4-o mutations is highly dependent on the RAD18 gene. Compared to the RAD strain, disruption of RAD52 reduced the frequency and yield of UV mutagenesis by about two-thirds. Closer inspection revealed that 80% of this reduction was due to a decrease in the frequency of G.C-->A.T transitions. In addition, there were differences in the distributions and site specificities of single base-pair substitutions. Thus, RAD52 also participates in UV mutagenesis of a plasmid-borne gene in yeast, but to a lesser extent than RAD18.

Fully functional global genome repair of (6-4) photoproducts and compromised transcription-coupled repair of cyclobutane pyrimidine dimers in condensed mitotic chromatin

Energy Technology Data Exchange (ETDEWEB)

Komura, Jun-ichiro, E-mail: junkom@med.tohoku.ac.jp [Department of Cell Biology, Tohoku University Graduate School of Medicine, Sendai 980-8575 (Japan); Ikehata, Hironobu [Department of Cell Biology, Tohoku University Graduate School of Medicine, Sendai 980-8575 (Japan); Mori, Toshio [Radioisotope Research Center, Nara Medical University, Kashihara, Nara 634-8521 (Japan); Ono, Tetsuya [Department of Cell Biology, Tohoku University Graduate School of Medicine, Sendai 980-8575 (Japan)

2012-03-10

During mitosis, chromatin is highly condensed, and activities such as transcription and semiconservative replication do not occur. Consequently, the condensed condition of mitotic chromatin is assumed to inhibit DNA metabolism by impeding the access of DNA-transacting proteins. However, about 40 years ago, several researchers observed unscheduled DNA synthesis in UV-irradiated mitotic chromosomes, suggesting the presence of excision repair. We re-examined this subject by directly measuring the removal of UV-induced DNA lesions by an ELISA and by a Southern-based technique in HeLa cells arrested at mitosis. We observed that the removal of (6-4) photoproducts from the overall genome in mitotic cells was as efficient as in interphase cells. This suggests that global genome repair of (6-4) photoproducts is fully functional during mitosis, and that the DNA in mitotic chromatin is accessible to proteins involved in this mode of DNA repair. Nevertheless, not all modes of DNA repair seem fully functional during mitosis. We also observed that the removal of cyclobutane pyrimidine dimers from the dihydrofolate reductase and c-MYC genes in mitotic cells was very slow. This suggests that transcription-coupled repair of cyclobutane pyrimidine dimers is compromised or non-functional during mitosis, which is probably the consequence of mitotic transcriptional repression. -- Highlights: Black-Right-Pointing-Pointer Global genome repair of (6-4) photoproducts is fully active in mitotic cells. Black-Right-Pointing-Pointer DNA in condensed mitotic chromatin does not seem inaccessible or inert. Black-Right-Pointing-Pointer Mitotic transcriptional repression may impair transcription-coupled repair.

Fully functional global genome repair of (6-4) photoproducts and compromised transcription-coupled repair of cyclobutane pyrimidine dimers in condensed mitotic chromatin

International Nuclear Information System (INIS)

Komura, Jun-ichiro; Ikehata, Hironobu; Mori, Toshio; Ono, Tetsuya

2012-01-01

During mitosis, chromatin is highly condensed, and activities such as transcription and semiconservative replication do not occur. Consequently, the condensed condition of mitotic chromatin is assumed to inhibit DNA metabolism by impeding the access of DNA-transacting proteins. However, about 40 years ago, several researchers observed unscheduled DNA synthesis in UV-irradiated mitotic chromosomes, suggesting the presence of excision repair. We re-examined this subject by directly measuring the removal of UV-induced DNA lesions by an ELISA and by a Southern-based technique in HeLa cells arrested at mitosis. We observed that the removal of (6-4) photoproducts from the overall genome in mitotic cells was as efficient as in interphase cells. This suggests that global genome repair of (6-4) photoproducts is fully functional during mitosis, and that the DNA in mitotic chromatin is accessible to proteins involved in this mode of DNA repair. Nevertheless, not all modes of DNA repair seem fully functional during mitosis. We also observed that the removal of cyclobutane pyrimidine dimers from the dihydrofolate reductase and c-MYC genes in mitotic cells was very slow. This suggests that transcription-coupled repair of cyclobutane pyrimidine dimers is compromised or non-functional during mitosis, which is probably the consequence of mitotic transcriptional repression. -- Highlights: ► Global genome repair of (6-4) photoproducts is fully active in mitotic cells. ► DNA in condensed mitotic chromatin does not seem inaccessible or inert. ► Mitotic transcriptional repression may impair transcription-coupled repair.

Discovery of a novel gene involved in autolysis of Clostridium cells.

Science.gov (United States)

Yang, Liejian; Bao, Guanhui; Zhu, Yan; Dong, Hongjun; Zhang, Yanping; Li, Yin

2013-06-01

Cell autolysis plays important physiological roles in the life cycle of clostridial cells. Understanding the genetic basis of the autolysis phenomenon of pathogenic Clostridium or solvent producing Clostridium cells might provide new insights into this important species. Genes that might be involved in autolysis of Clostridium acetobutylicum, a model clostridial species, were investigated in this study. Twelve putative autolysin genes were predicted in C. acetobutylicum DSM 1731 genome through bioinformatics analysis. Of these 12 genes, gene SMB_G3117 was selected for testing the in tracellular autolysin activity, growth profile, viable cell numbers, and cellular morphology. We found that overexpression of SMB_G3117 gene led to earlier ceased growth, significantly increased number of dead cells, and clear electrolucent cavities, while disruption of SMB_G3117 gene exhibited remarkably reduced intracellular autolysin activity. These results indicate that SMB_G3117 is a novel gene involved in cellular autolysis of C. acetobutylicum.

Constitutional chromothripsis rearrangements involve clustered double-stranded DNA breaks and nonhomologous repair mechanisms.

Science.gov (United States)

Kloosterman, Wigard P; Tavakoli-Yaraki, Masoumeh; van Roosmalen, Markus J; van Binsbergen, Ellen; Renkens, Ivo; Duran, Karen; Ballarati, Lucia; Vergult, Sarah; Giardino, Daniela; Hansson, Kerstin; Ruivenkamp, Claudia A L; Jager, Myrthe; van Haeringen, Arie; Ippel, Elly F; Haaf, Thomas; Passarge, Eberhard; Hochstenbach, Ron; Menten, Björn; Larizza, Lidia; Guryev, Victor; Poot, Martin; Cuppen, Edwin

2012-06-28

Chromothripsis represents a novel phenomenon in the structural variation landscape of cancer genomes. Here, we analyze the genomes of ten patients with congenital disease who were preselected to carry complex chromosomal rearrangements with more than two breakpoints. The rearrangements displayed unanticipated complexity resembling chromothripsis. We find that eight of them contain hallmarks of multiple clustered double-stranded DNA breaks (DSBs) on one or more chromosomes. In addition, nucleotide resolution analysis of 98 breakpoint junctions indicates that break repair involves nonhomologous or microhomology-mediated end joining. We observed that these eight rearrangements are balanced or contain sporadic deletions ranging in size between a few hundred base pairs and several megabases. The two remaining complex rearrangements did not display signs of DSBs and contain duplications, indicative of rearrangement processes involving template switching. Our work provides detailed insight into the characteristics of chromothripsis and supports a role for clustered DSBs driving some constitutional chromothripsis rearrangements. Copyright © 2012 The Authors. Published by Elsevier Inc. All rights reserved.

Hereditary Ovarian Cancer: Not Only BRCA 1 and 2 Genes

Directory of Open Access Journals (Sweden)

Angela Toss

2015-01-01

Full Text Available More than one-fifth of ovarian tumors have hereditary susceptibility and, in about 65–85% of these cases, the genetic abnormality is a germline mutation in BRCA genes. Nevertheless, several other suppressor genes and oncogenes have been associated with hereditary ovarian cancers, including the mismatch repair (MMR genes in Lynch syndrome, the tumor suppressor gene, TP53, in the Li-Fraumeni syndrome, and several other genes involved in the double-strand breaks repair system, such as CHEK2, RAD51, BRIP1, and PALB2. The study of genetic discriminators and deregulated pathways involved in hereditary ovarian syndromes is relevant for the future development of molecular diagnostic strategies and targeted therapeutic approaches. The recent development and implementation of next-generation sequencing technologies have provided the opportunity to simultaneously analyze multiple cancer susceptibility genes, reduce the delay and costs, and optimize the molecular diagnosis of hereditary tumors. Particularly, the identification of mutations in ovarian cancer susceptibility genes in healthy women may result in a more personalized cancer risk management with tailored clinical and radiological surveillance, chemopreventive approaches, and/or prophylactic surgeries. On the other hand, for ovarian cancer patients, the identification of mutations may provide potential targets for biologic agents and guide treatment decision-making.

Molecular cloning of a mouse DNA repair gene that complements the defect of group-A xeroderma pigmentosum

International Nuclear Information System (INIS)

Tanaka, K.; Satokata, I.; Ogita, Z.; Uchida, T.; Okada, Y.

1989-01-01

For isolation of the gene responsible for xeroderma pigmentosum (XP) complementation group A, plasmid pSV2gpt and genomic DNA from a mouse embryo were cotransfected into XP2OSSV cells, a group-A XP cell line. Two primary UV-resistant XP transfectants were isolated from about 1.6 X 10(5) pSV2gpt-transformed XP colonies. pSV2gpt and genomic DNA from the primary transfectants were again cotransfected into XP2OSSV cells and a secondary UV-resistant XP transfectant was obtained by screening about 4.8 X 10(5) pSV2gpt-transformed XP colonies. The secondary transfectant retained fewer mouse repetitive sequences. A mouse gene that complements the defect of XP2OSSV cells was cloned into an EMBL3 vector from the genome of a secondary transfectant. Transfections of the cloned DNA also conferred UV resistance on another group-A XP cell line but not on XP cell lines of group C, D, F, or G. Northern blot analysis of poly(A)+ RNA with a subfragment of cloned mouse DNA repair gene as the probe revealed that an approximately 1.0 kilobase mRNA was transcribed in the donor mouse embryo and secondary transfectant, and approximately 1.0- and approximately 1.3-kilobase mRNAs were transcribed in normal human cells, but none of these mRNAs was detected in three strains of group-A XP cells. These results suggest that the cloned DNA repair gene is specific for group-A XP and may be the mouse homologue of the group-A XP human gene

Are glutathione S transferases involved in DNA damage signalling? Interactions with DNA damage and repair revealed from molecular epidemiology studies

International Nuclear Information System (INIS)

Dusinska, Maria; Staruchova, Marta; Horska, Alexandra; Smolkova, Bozena; Collins, Andrew; Bonassi, Stefano; Volkovova, Katarina

2012-01-01

Glutathione S-transferases (GSTs) are members of a multigene family of isoenzymes that are important in the control of oxidative stress and in phase II metabolism. Acting non-enzymically, GSTs can modulate signalling pathways of cell proliferation, cell differentiation and apoptosis. Using a molecular epidemiology approach, we have investigated a potential involvement of GSTs in DNA damage processing, specifically the modulation of DNA repair in a group of 388 healthy adult volunteers; 239 with at least 5 years of occupational exposure to asbestos, stone wool or glass fibre, and 149 reference subjects. We measured DNA damage in lymphocytes using the comet assay (alkaline single cell gel electrophoresis): strand breaks (SBs) and alkali-labile sites, oxidised pyrimidines with endonuclease III, and oxidised purines with formamidopyrimidine DNA glycosylase. We also measured GST activity in erythrocytes, and the capacity for base excision repair (BER) in a lymphocyte extract. Polymorphisms in genes encoding three GST isoenzymes were determined, namely deletion of GSTM1 and GSTT1 and single nucleotide polymorphism Ile105Val in GSTP1. Consumption of vegetables and wine correlated negatively with DNA damage and modulated BER. GST activity correlated with oxidised bases and with BER capacity, and differed depending on polymorphisms in GSTP1, GSTT1 and GSTM1. A significantly lower BER rate was associated with the homozygous GSTT1 deletion in all asbestos site subjects and in the corresponding reference group. Multifactorial analysis revealed effects of sex and exposure in GSTP1 Ile/Val heterozygotes but not in Ile/Ile homozygotes. These variants affected also SBs levels, mainly by interactions of GSTP1 genotype with exposure, with sex, and with smoking habit; and by an interaction between sex and smoking. Our results show that GST polymorphisms and GST activity can apparently influence DNA stability and repair of oxidised bases, suggesting a potential new role for these

Are glutathione S transferases involved in DNA damage signalling? Interactions with DNA damage and repair revealed from molecular epidemiology studies

Energy Technology Data Exchange (ETDEWEB)

Dusinska, Maria, E-mail: Maria.DUSINSKA@nilu.no [CEE-Health Effects Group, NILU - Norwegian Institute for Air Research, Kjeller (Norway); Staruchova, Marta; Horska, Alexandra [Department of Experimental and Applied Genetics, Slovak Medical University, Bratislava (Slovakia); Smolkova, Bozena [Laboratory of Cancer Genetics, Cancer Research Institute of the Slovak Academy of Sciences, Bratislava (Slovakia); Collins, Andrew [Department of Nutrition, Faculty of Medicine, University of Oslo (Norway); Bonassi, Stefano [Unit of Clinical and Molecular Epidemiology, IRCCS San Raffaele Pisana, Rome (Italy); Volkovova, Katarina [Department of Experimental and Applied Genetics, Slovak Medical University, Bratislava (Slovakia)

2012-08-01

Glutathione S-transferases (GSTs) are members of a multigene family of isoenzymes that are important in the control of oxidative stress and in phase II metabolism. Acting non-enzymically, GSTs can modulate signalling pathways of cell proliferation, cell differentiation and apoptosis. Using a molecular epidemiology approach, we have investigated a potential involvement of GSTs in DNA damage processing, specifically the modulation of DNA repair in a group of 388 healthy adult volunteers; 239 with at least 5 years of occupational exposure to asbestos, stone wool or glass fibre, and 149 reference subjects. We measured DNA damage in lymphocytes using the comet assay (alkaline single cell gel electrophoresis): strand breaks (SBs) and alkali-labile sites, oxidised pyrimidines with endonuclease III, and oxidised purines with formamidopyrimidine DNA glycosylase. We also measured GST activity in erythrocytes, and the capacity for base excision repair (BER) in a lymphocyte extract. Polymorphisms in genes encoding three GST isoenzymes were determined, namely deletion of GSTM1 and GSTT1 and single nucleotide polymorphism Ile105Val in GSTP1. Consumption of vegetables and wine correlated negatively with DNA damage and modulated BER. GST activity correlated with oxidised bases and with BER capacity, and differed depending on polymorphisms in GSTP1, GSTT1 and GSTM1. A significantly lower BER rate was associated with the homozygous GSTT1 deletion in all asbestos site subjects and in the corresponding reference group. Multifactorial analysis revealed effects of sex and exposure in GSTP1 Ile/Val heterozygotes but not in Ile/Ile homozygotes. These variants affected also SBs levels, mainly by interactions of GSTP1 genotype with exposure, with sex, and with smoking habit; and by an interaction between sex and smoking. Our results show that GST polymorphisms and GST activity can apparently influence DNA stability and repair of oxidised bases, suggesting a potential new role for these

Genes on chromosomes 1 and 4 in the mouse are associated with repair of radiation-induced chromatin damage.

Science.gov (United States)

Potter, M; Sanford, K K; Parshad, R; Tarone, R E; Price, F M; Mock, B; Huppi, K

1988-04-01

Early-passage skin fibroblasts from different inbred and congenic strains of mice were X-irradiated (1 Gy), and the number of chromatid breaks was determined at 2.0 h after irradiation. The cells from DBA/2N, C3H/HeN, STS/A, C57BL/6N, BALB/cJ, and AKR/N had 25 to 42 chromatid breaks per 100 metaphase cells (efficient repair phenotype). NZB/NJ had greater than 78 and BALB/cAn had 87 to 110 chromatid breaks per 100 cells (inefficient repair phenotype). Differences between BALB/cAn and BALB/c. DBA/2 congenic strains which carry less than 1% of the DBA/2 genome indicate that two genes, one on chromosome 1 linked to bcl-2-Pep-3 and the other on chromosome 4 closely linked to Fv-1, affect the efficiency with which the cells repair radiation-induced chromatin damage.

CCDB: a curated database of genes involved in cervix cancer.

Science.gov (United States)

Agarwal, Subhash M; Raghav, Dhwani; Singh, Harinder; Raghava, G P S

2011-01-01

The Cervical Cancer gene DataBase (CCDB, http://crdd.osdd.net/raghava/ccdb) is a manually curated catalog of experimentally validated genes that are thought, or are known to be involved in the different stages of cervical carcinogenesis. In spite of the large women population that is presently affected from this malignancy still at present, no database exists that catalogs information on genes associated with cervical cancer. Therefore, we have compiled 537 genes in CCDB that are linked with cervical cancer causation processes such as methylation, gene amplification, mutation, polymorphism and change in expression level, as evident from published literature. Each record contains details related to gene like architecture (exon-intron structure), location, function, sequences (mRNA/CDS/protein), ontology, interacting partners, homology to other eukaryotic genomes, structure and links to other public databases, thus augmenting CCDB with external data. Also, manually curated literature references have been provided to support the inclusion of the gene in the database and establish its association with cervix cancer. In addition, CCDB provides information on microRNA altered in cervical cancer as well as search facility for querying, several browse options and an online tool for sequence similarity search, thereby providing researchers with easy access to the latest information on genes involved in cervix cancer.

XRCC1 and XPD DNA repair gene polymorphisms: a potential risk factor for glaucoma in the Pakistani population

NARCIS (Netherlands)

Yousaf, S.; Khan, M.I.; Micheal, S.; Akhtar, F.; Ali, S.H.; Riaz, M.; Ali, M.; Lall, P.; Waheed, N.K.; Hollander, A.I. den; Ahmed, A.; Qamar, R.

2011-01-01

PURPOSE: The present study was designed to determine the association of polymorphisms of the DNA repair genes X-ray cross-complementing group 1 (XRCC1) (c.1316G>A [rs25487]) and xeroderma pigmentosum complementation group D (XPD) (c.2298A>C [rs13181]) with primary open-angle glaucoma (POAG) and

Repair of DNA treated with λ-irradiation and chemical carcinogens: Progress report (1983-1986)

International Nuclear Information System (INIS)

Goldthwait, D.A.

1986-01-01

This progress report summarizes work on DNA repair of chromatin and then details our progress in developing three model systems. These model systems center on signal transduction in cancer and in carcinogenesis. Molecular biological approaches to three model systems are being developed. The first involves signal transduction controlling sis gene (platelet derived growth factor-β) mRNA levels in human glioblastoma cells. The second involves signal transduction in the activation of a long terminal repeat. The third involves an experiment designed to detect a transposition event in a human cell

International congress on DNA damage and repair: Book of abstracts

International Nuclear Information System (INIS)

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

Gene Expression Profiling in the Injured Spinal Cord of Trachemys scripta elegans: An Amniote with Self-Repair Capabilities

Science.gov (United States)

Valentin-Kahan, Adrián; García-Tejedor, Gabriela B.; Robello, Carlos; Trujillo-Cenóz, Omar; Russo, Raúl E.; Alvarez-Valin, Fernando

2017-01-01

Slider turtles are the only known amniotes with self-repair mechanisms of the spinal cord that lead to substantial functional recovery. Their strategic phylogenetic position makes them a relevant model to investigate the peculiar genetic programs that allow anatomical reconnection in some vertebrate groups but are absent in others. Here, we analyze the gene expression profile of the response to spinal cord injury (SCI) in the turtle Trachemys scripta elegans. We found that this response comprises more than 1000 genes affecting diverse functions: reaction to ischemic insult, extracellular matrix re-organization, cell proliferation and death, immune response, and inflammation. Genes related to synapses and cholesterol biosynthesis are down-regulated. The analysis of the evolutionary distribution of these genes shows that almost all are present in most vertebrates. Additionally, we failed to find genes that were exclusive of regenerating taxa. The comparison of expression patterns among species shows that the response to SCI in the turtle is more similar to that of mice and non-regenerative Xenopus than to Xenopus during its regenerative stage. This observation, along with the lack of conserved “regeneration genes” and the current accepted phylogenetic placement of turtles (sister group of crocodilians and birds), indicates that the ability of spinal cord self-repair of turtles does not represent the retention of an ancestral vertebrate character. Instead, our results suggest that turtles developed this capability from a non-regenerative ancestor (i.e., a lineage specific innovation) that was achieved by re-organizing gene expression patterns on an essentially non-regenerative genetic background. Among the genes activated by SCI exclusively in turtles, those related to anoxia tolerance, extracellular matrix remodeling, and axonal regrowth are good candidates to underlie functional recovery. PMID:28223917

Involvement of the DNA mismatch repair system in cisplatin sensitivity of testicular germ cell tumours

DEFF Research Database (Denmark)

Rudolph, Christiane; Melau, Cecilie; Nielsen, John E.

2017-01-01

in the majority of tumours, although the underlying mechanism largely remains to be elucidated. The aim of this study was to investigate the role of the DNA mismatch repair (MMR) system in the cisplatin sensitivity of TGCT. MethodsThe expression pattern of key MMR proteins, including MSH2, MSH6, MLH1 and PMS2...... proteins, in particular MSH2 and MLH1, which are involved in the recognition of cisplatin adducts and in activation of the DNA damage response pathway to initiate apoptosis....

Survival and SOS response induction in ultraviolet B irradiated Escherichia coli cells with defective repair mechanisms.

Science.gov (United States)

Prada Medina, Cesar Augusto; Aristizabal Tessmer, Elke Tatjana; Quintero Ruiz, Nathalia; Serment-Guerrero, Jorge; Fuentes, Jorge Luis

2016-06-01

Purpose In this paper, the contribution of different genes involved in DNA repair for both survival and SOS induction in Escherichia coli mutants exposed to ultraviolet B radiation (UVB, [wavelength range 280-315 nm]) was evaluated. Materials and methods E. coli strains defective in uvrA, oxyR, recO, recN, recJ, exoX, recB, recD or xonA genes were used to determine cell survival. All strains also had the genetic sulA::lacZ fusion, which allowed for the quantification of SOS induction through the SOS Chromotest. Results Five gene products were particularly important for survival, as follows: UvrA > RecB > RecO > RecJ > XonA. Strains defective in uvrA and recJ genes showed elevated SOS induction compared with the wild type, which remained stable for up to 240 min after UVB-irradiation. In addition, E. coli strains carrying the recO or recN mutation showed no SOS induction. Conclusions The nucleotide excision and DNA recombination pathways were equally used to repair UVB-induced DNA damage in E. coli cells. The sulA gene was not turned off in strains defective in UvrA and RecJ. RecO protein was essential for processing DNA damage prior to SOS induction. In this study, the roles of DNA repair proteins and their contributions to the mechanisms that induce SOS genes in E. coli are proposed.

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.

Common variants in mismatch repair genes associated with increased risk of sperm DNA damage and male infertility

Directory of Open Access Journals (Sweden)

Ji Guixiang

2012-05-01

Full Text Available Abstract Background The mismatch repair (MMR pathway plays an important role in the maintenance of the genome integrity, meiotic recombination and gametogenesis. This study investigated whether genetic variations in MMR genes are associated with an increased risk of sperm DNA damage and male infertility. Methods We selected and genotyped 21 tagging single nucleotide polymorphisms (SNPs in five MMR genes (MLH1, MLH3, PMS2, MSH4 and MSH5 using the SNPstream 12-plex platform in a case-control study of 1,292 idiopathic infertility patients and 480 fertile controls in a Chinese population. Sperm DNA damage levels were detected with the Tdt-mediated dUTP nick end labelling (TUNEL assay in 450 cases. Fluorescence resonance energy transfer (FRET and co-immunoprecipitation techniques were employed to determine the effects of functional variants. Results One intronic SNP in MLH1 (rs4647269 and two non-synonymous SNPs in PMS2 (rs1059060, Ser775Asn and MSH5 (rs2075789, Pro29Ser seem to be risk factors for the development of azoospermia or oligozoospermia. Meanwhile, we also identified a possible contribution of PMS2 rs1059060 to the risk of male infertility with normal sperm count. Among patients with normal sperm count, MLH1 rs4647269 and PMS2 rs1059060 were associated with increased sperm DNA damage. Functional analysis revealed that the PMS2 rs1059060 can affect the interactions between MLH1 and PMS2. Conclusions Our results provide evidence supporting the involvement of genetic polymorphisms in MMR genes in the aetiology of male infertility.

Evidence for three types of x-ray damage repair in yeast and sensitivity of totally repair deficient strains to sunlight

International Nuclear Information System (INIS)

Game, J.C.; Schild, D.; Mortimer, R.K.

1987-01-01

Mutants of yeast that confer sensitivity to x-rays are known to fall into two epistasis groups, called here the RAD51 and RAD18 groups, which are each thought to control a different type of x-ray repair. They examine here the role of genes in a third repair pathways in x-ray repair. RAD1 and RAD3 are known to be important in the repair of pyrimidine dimers after uv-irradiation. They find that these genes can also play an important role in x-ray repair, but that this role is only exposed when both the other pathways of x-ray repair are blocked. Double mutants blocked in the RAD51 and RAD18 pathways are significantly less x-ray sensitive than triple mutants blocked in these pathways but also mutant in either the RAD1 or RAD3 genes. In a related experiment, they tested the importance of DNA repair in nature by determining the sensitivity to natural unfiltered sunlight of a strain lacking all known DNA repair pathways. They constructed a quadruple mutant strain containing RAD1-1, RAD18-2, RAD51-1 and PHR1-1. The latter mutation blocks the cell's ability to photoreactivate uv damage. They found that this strain was so sensitive to sunlight that less than three seconds' exposure would cause an average of one lethal hit per cell, and survival was less than 2% after ten seconds' exposure. Wild type yeast at sea level showed no killing after thirty minutes. the quadruple mutant is approximately one thousand times more sensitive to sunlight than the related wild type

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)

Correlation between ultraviolet survival and DNA repair efficiency in mouse cell hybrids and their parent lines

International Nuclear Information System (INIS)

Limbosch, S.

1982-01-01

Three hybrid cell lines formed between mouse lymphoma (LS) and mouse fibroblasts (A9) have been tested for their capacity to perform unscheduled DNA synthesis; their recovery characteristics after uv irradiation have also been studied to determine if DNA repair is implicated in the high survival observed in one hybrid (clone 3). The results of these investigations indicate that hybrid clone 3 was distinguishable from the more uv sensitive parental and other hybrid cell lines by its higher uv-induced unscheduled DNA synthesis, its greater clonogenic survival in plateau phase, and its faster recovery when maintained in conditioned medium after irradiation. The simultaneous increase of these three properties in hybrid clone 3 suggest that, by three different approaches, we have evidenced the same molecular process, a process involved in the elimination of potentially lethal damage, most probably the excision repair pathway. This report also shows that the low efficiency in excision repair in the parent line A9 is probably not due to deletion but rather to repression of the relevant gene(s) and that somatic cell hybridization can result in a stimulation of a previously poorly expressed repair process

Evaluation of the XRCC1 gene as a phenotypic modifier in BRCA1/2 mutation carriers. Results from the consortium of investigators of modifiers of BRCA1/BRCA2

NARCIS (Netherlands)

Osorio, A.; Milne, R. L.; Alonso, R.; Pita, G.; Peterlongo, P.; Teulé, A.; Nathanson, K. L.; Domchek, S. M.; Rebbeck, T.; Lasa, A.; Konstantopoulou, I.; Hogervorst, F. B.; Verhoef, S.; van Dooren, M. F.; Jager, A.; Ausems, M. G. E. M.; Aalfs, C. M.; van Asperen, C. J.; Vreeswijk, M.; Waisfisz, Q.; van Roozendaal, C. E.; Ligtenberg, M. J.; Easton, D. F.; Peock, S.; Cook, M.; Oliver, C. T.; Frost, D.; Curzon, B.; Evans, D. G.; Lalloo, F.; Eeles, R.; Izatt, L.; Davidson, R.; Adlard, J.; Eccles, D.; Ong, K.-r; Douglas, F.; Downing, S.; Brewer, C.; Walker, L.; Nevanlinna, H.; Aittomäki, K.; Couch, F. J.; Fredericksen, Z.; Lindor, N. M.; Godwin, A.; Isaacs, C.; Caligo, M. A.; Loman, N.; Jernström, H.; Barbany-Bustinza, G.; Liljegren, A.; Ehrencrona, H.; Stenmark-Askmalm, M.; Feliubadaló, L.; Manoukian, S.; Peissel, B.; Zaffaroni, D.; Bonanni, B.; Fortuzzi, S.; Johannsson, O. T.; Chenevix-Trench, G.; Chen, X.-C.; Beesley, J.; Spurdle, A. B.; Sinilnikova, O. M.; Healey, S.; McGuffog, L.; Antoniou, A. C.; Brunet, J.; Radice, P.; Benítez, J.; Hogervorst, F. B. L.; Verheus, M.; van 't Veer, L. J.; van Leeuwen, F. E.; Rookus, M. A.; Collée, M.; van den Ouweland, A. M. W.; Hooning, M. J.; Tilanus-Linthorst, M. M. A.; Seynaeve, C.; Wijnen, J. T.; Vreeswijk, M. P.; Tollenaar, R. A.; Devilee, P.; Hoogerbrugge, N.; Ausems, M. G.; van der Luijt, R. B.; van Os, T. A.; Gille, J. J. P.; Meijers-Heijboer, H. E. J.; Gomez-Garcia, E. B.; Blok, Marinus J.; Caanen, B.; Oosterwijk, J. C.; van der Hout, A. H.; Mourits, M. J.; Vasen, H. F.; Peock, Susan; Cook, Margaret; Oliver, Clare; Frost, Debra; Miedzybrodzka, Zosia; Gregory, Helen; Morrison, Patrick; Jeffers, Lisa; Cole, Trevor; McKeown, Carole; Ong, Kai-Ren; Hoffman, Jonathan; Donaldson, Alan; Paterson, Joan; Downing, Sarah; Taylor, Amy; Murray, Alexandra; Rogers, Mark T.; McCann, Emma; Kennedy, M. John; Barton, David; East, South; Porteous, Mary; Drummond, Sarah; Brewer, Carole; Kivuva, Emma; Searle, Anne; Goodman, Selina; Hill, Kathryn; Davidson, Rosemarie; Bradshaw, Nicola; Snadden, Lesley; Longmuir, Mark; Watt, Catherine; Gibson, Sarah; Izatt, Louise; Jacobs, Chris; Langman, Caroline; Whaite, Anna; Dorkins, Huw; Barwell, Julian; Adlard, Julian; Chu, Carol; Miller, Julie; Ellis, Ian; Evans, D. Gareth; Lalloo, Fiona; Taylor, Jane; Side, Lucy; Male, Alison; Berlin, Cheryl; Eason, Jacqueline; Collier, Rebecca; Douglas, Fiona; Claber, Oonagh; Walker, Lisa; McLeod, Diane; Halliday, Dorothy; Durell, Sarah; Stayner, Barbara; Eeles, Ros; Shanley, Susan; Rahman, Nazneen; Houlston, Richard; Bancroft, Elizabeth; D'Mello, Lucia; Page, Elizabeth; Ardern-Jones, Audrey; Kohut, Kelly; Wiggins, Jennifer; Castro, Elena; Mitra, Anitra; Robertson, Lisa; Cook, Jackie; Quarrell, Oliver; Bardsley, Cathryn; Hodgson, Shirley; Goff, Sheila; Brice, Glen; Winchester, Lizzie; Eddy, Charlotte; Tripathi, Vishakha; Attard, Virginia; Eccles, Diana; Lucassen, Anneke; Crawford, Gillian; McBride, Donna; Smalley, Sarah; Godwin, A. K.; Karlsson, Per; Nordling, Margareta; Bergman, Annika; Einbeigi, Zakaria; Stenmark- Askmalm, Marie; Liedgren, Sigrun; Borg, Ake; Loman, Niklas; Olsson, Håkan; Kristoffersson, Ulf; Jernström, Helena; Harbst, Katja; Henriksson, Karin; Lindblom, Annika; Arver, Brita; Wachenfeldt, Anna von; Liljegren, Annelie; Barbany-Bustinza, Gisela; Rantala, Johanna; Melin, Beatrice; Grönberg, Henrik; Stattin, Eva-Lena; Emanuelsson, Monica; Ehrencrona, Hans; Rosenquist Brandell, Richard; Dahl, Niklas

2011-01-01

Single-nucleotide polymorphisms (SNPs) in genes involved in DNA repair are good candidates to be tested as phenotypic modifiers for carriers of mutations in the high-risk susceptibility genes BRCA1 and BRCA2. The base excision repair (BER) pathway could be particularly interesting given the relation

Assessing SNP-SNP interactions among DNA repair, modification and metabolism related pathway genes in breast cancer susceptibility.

Directory of Open Access Journals (Sweden)

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

Base excision repair in Archaea: back to the future in DNA repair.

Science.gov (United States)

Grasso, Stefano; Tell, Gianluca

2014-09-01

Together with Bacteria and Eukarya, Archaea represents one of the three domain of life. In contrast with the morphological difference existing between Archaea and Eukarya, these two domains are closely related. Phylogenetic analyses confirm this evolutionary relationship showing that most of the proteins involved in DNA transcription and replication are highly conserved. On the contrary, information is scanty about DNA repair pathways and their mechanisms. In the present review the most important proteins involved in base excision repair, namely glycosylases, AP lyases, AP endonucleases, polymerases, sliding clamps, flap endonucleases, and ligases, will be discussed and compared with bacterial and eukaryotic ones. Finally, possible applications and future perspectives derived from studies on Archaea and their repair pathways, will be taken into account. Copyright © 2014 Elsevier B.V. All rights reserved.

Epidermal wound repair is regulated by the planar cell polarity signaling pathway.

Science.gov (United States)

Caddy, Jacinta; Wilanowski, Tomasz; Darido, Charbel; Dworkin, Sebastian; Ting, Stephen B; Zhao, Quan; Rank, Gerhard; Auden, Alana; Srivastava, Seema; Papenfuss, Tony A; Murdoch, Jennifer N; Humbert, Patrick O; Parekh, Vishwas; Boulos, Nidal; Weber, Thomas; Zuo, Jian; Cunningham, John M; Jane, Stephen M

2010-07-20

The mammalian PCP pathway regulates diverse developmental processes requiring coordinated cellular movement, including neural tube closure and cochlear stereociliary orientation. Here, we show that epidermal wound repair is regulated by PCP signaling. Mice carrying mutant alleles of PCP genes Vangl2, Celsr1, PTK7, and Scrb1, and the transcription factor Grhl3, interact genetically, exhibiting failed wound healing, neural tube defects, and disordered cochlear polarity. Using phylogenetic analysis, ChIP, and gene expression in Grhl3(-)(/-) mice, we identified RhoGEF19, a homolog of a RhoA activator involved in PCP signaling in Xenopus, as a direct target of GRHL3. Knockdown of Grhl3 or RhoGEF19 in keratinocytes induced defects in actin polymerization, cellular polarity, and wound healing, and re-expression of RhoGEF19 rescued these defects in Grhl3-kd cells. These results define a role for Grhl3 in PCP signaling and broadly implicate this pathway in epidermal repair. (c) 2010 Elsevier Inc. All rights reserved.

Differences of RNA Expression in the Tendon According to Anatomic Outcomes in Rotator Cuff Repair.

Science.gov (United States)

Ahn, Jin-Ok; Chung, Jin-Young; Kim, Do Hoon; Im, Wooseok; Kim, Sae Hoon

2017-11-01

Despite increased understanding of the pathophysiology of rotator cuff tears and the evolution of rotator cuff repair, healing failure remains a substantial problem. The critical roles played by biological factors have been emphasized, but little is known of the implications of gene expression profile differences at the time of repair. To document the relationship between the perioperative gene expression of healed and unhealed rotator cuffs by RNA microarray analysis. Case-control study; Level of evidence, 3. Superior (supraspinatus involvement) and posterosuperior (supraspinatus and infraspinatus involvement) tears were included in the study. Samples of rotator cuff tendons were prospectively collected during rotator cuff surgery. Three samples were harvested at the tendon ends of tears from the anterior, middle (apex), and posterior parts using an arthroscopic punch. Seven patients with an unhealed rotator cuff were matched one-to-one with patients with a healed rotator cuff by sex, age, tear size, and fatty degeneration of rotator cuff muscles. mRNA microarray analysis was used to identify genetic differences between healed and unhealed rotator cuff tendons. Gene ontology and gene association files were obtained from the Gene Ontology Consortium, and the Gene Ontology system in DAVID was used to identify enhanced biological processes. Microarray analyses identified 262 genes that were differentially expressed by at least 1.5-fold between the healed and unhealed groups. Overall, in the healed group, 103 genes were significantly downregulated, and 159 were significantly upregulated. DAVID Functional Annotation Cluster analysis showed that in the healed group, the genes most upregulated were related to the G protein-coupled receptor protein signaling pathway and to the neurological system. On the other hand, the genes most downregulated were related to immune and inflammatory responses. BMP5 was the gene most upregulated in the healed group, and the majority of

Improved fermentation performance of a lager yeast after repair of its AGT1 maltose and maltotriose transporter genes.

Science.gov (United States)

Vidgren, Virve; Huuskonen, Anne; Virtanen, Hannele; Ruohonen, Laura; Londesborough, John

2009-04-01

The use of more concentrated, so-called high-gravity and very-high-gravity (VHG) brewer's worts for the manufacture of beer has economic and environmental advantages. However, many current strains of brewer's yeasts ferment VHG worts slowly and incompletely, leaving undesirably large amounts of maltose and especially maltotriose in the final beers. alpha-Glucosides are transported into Saccharomyces yeasts by several transporters, including Agt1, which is a good carrier of both maltose and maltotriose. The AGT1 genes of brewer's ale yeast strains encode functional transporters, but the AGT1 genes of the lager strains studied contain a premature stop codon and do not encode functional transporters. In the present work, one or more copies of the AGT1 gene of a lager strain were repaired with DNA sequence from an ale strain and put under the control of a constitutive promoter. Compared to the untransformed strain, the transformants with repaired AGT1 had higher maltose transport activity, especially after growth on glucose (which represses endogenous alpha-glucoside transporter genes) and higher ratios of maltotriose transport activity to maltose transport activity. They fermented VHG (24 degrees Plato) wort faster and more completely, producing beers containing more ethanol and less residual maltose and maltotriose. The growth and sedimentation behaviors of the transformants were similar to those of the untransformed strain, as were the profiles of yeast-derived volatile aroma compounds in the beers.

Chromosome End Repair and Genome Stability in Plasmodium falciparum.

Science.gov (United States)

Calhoun, Susannah F; Reed, Jake; Alexander, Noah; Mason, Christopher E; Deitsch, Kirk W; Kirkman, Laura A

2017-08-08

The human malaria parasite Plasmodium falciparum replicates within circulating red blood cells, where it is subjected to conditions that frequently cause DNA damage. The repair of DNA double-stranded breaks (DSBs) is thought to rely almost exclusively on homologous recombination (HR), due to a lack of efficient nonhomologous end joining. However, given that the parasite is haploid during this stage of its life cycle, the mechanisms involved in maintaining genome stability are poorly understood. Of particular interest are the subtelomeric regions of the chromosomes, which contain the majority of the multicopy variant antigen-encoding genes responsible for virulence and disease severity. Here, we show that parasites utilize a competitive balance between de novo telomere addition, also called "telomere healing," and HR to stabilize chromosome ends. Products of both repair pathways were observed in response to DSBs that occurred spontaneously during routine in vitro culture or resulted from experimentally induced DSBs, demonstrating that both pathways are active in repairing DSBs within subtelomeric regions and that the pathway utilized was determined by the DNA sequences immediately surrounding the break. In combination, these two repair pathways enable parasites to efficiently maintain chromosome stability while also contributing to the generation of genetic diversity. IMPORTANCE Malaria is a major global health threat, causing approximately 430,000 deaths annually. This mosquito-transmitted disease is caused by Plasmodium parasites, with infection with the species Plasmodium falciparum being the most lethal. Mechanisms underlying DNA repair and maintenance of genome integrity in P. falciparum are not well understood and represent a gap in our understanding of how parasites survive the hostile environment of their vertebrate and insect hosts. Our work examines DNA repair in real time by using single-molecule real-time (SMRT) sequencing focused on the subtelomeric

The sf32 unique gene of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV is a non-essential gene that could be involved in nucleocapsid organization in occlusion-derived virions.

Directory of Open Access Journals (Sweden)

Inés Beperet

Full Text Available A recombinant virus lacking the sf32 gene (Sf32null, unique to the Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV, was generated by homologous recombination from a bacmid comprising the complete viral genome (Sfbac. Transcriptional analysis revealed that sf32 is an early gene. Occlusion bodies (OBs of Sf32null contained 62% more genomic DNA than viruses containing the sf32 gene, Sfbac and Sf32null-repair, although Sf32null DNA was three-fold less infective when injected in vivo. Sf32null OBs were 18% larger in diameter and contained 17% more nucleocapsids within ODVs than those of Sfbac. No significant differences were detected in OB pathogenicity (50% lethal concentration, speed-of-kill or budded virus production in vivo. In contrast, the production of OBs/larva was reduced by 39% in insects infected by Sf32null compared to those infected by Sfbac. The SF32 predicted protein sequence showed homology (25% identity, 44% similarity to two adhesion proteins from Streptococcus pyogenes and a single N-mirystoylation site was predicted. We conclude that SF32 is a non-essential protein that could be involved in nucleocapsid organization during ODV assembly and occlusion, resulting in increased numbers of nucleocapsids within ODVs.

Nucleotide Excision DNA Repair is Associated with Age-Related Vascular Dysfunction

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Durik, Matej; Kavousi, Maryam; van der Pluijm, Ingrid; Isaacs, Aaron; Cheng, Caroline; Verdonk, Koen; Loot, Annemarieke E.; Oeseburg, Hisko; Musterd-Bhaggoe, Usha; Leijten, Frank; van Veghel, Richard; de Vries, Rene; Rudez, Goran; Brandt, Renata; Ridwan, Yanto R.; van Deel, Elza D.; de Boer, Martine; Tempel, Dennie; Fleming, Ingrid; Mitchell, Gary F.; Verwoert, Germaine C.; Tarasov, Kirill V.; Uitterlinden, Andre G.; Hofman, Albert; Duckers, Henricus J.; van Duijn, Cornelia M.; Oostra, Ben A.; Witteman, Jacqueline C.M.; Duncker, Dirk J.; Danser, A.H. Jan; Hoeijmakers, Jan H.; Roks, Anton J.M.

2012-01-01

Background Vascular dysfunction in atherosclerosis and diabetes, as observed in the aging population of developed societies, is associated with vascular DNA damage and cell senescence. We hypothesized that cumulative DNA damage during aging contributes to vascular dysfunction. Methods and Results In mice with genomic instability due to the defective nucleotide excision repair genes ERCC1 and XPD (Ercc1d/− and XpdTTD mice), we explored age-dependent vascular function as compared to wild-type mice. Ercc1d/− mice showed increased vascular cell senescence, accelerated development of vasodilator dysfunction, increased vascular stiffness and elevated blood pressure at very young age. The vasodilator dysfunction was due to decreased endothelial eNOS levels as well as impaired smooth muscle cell function, which involved phosphodiesterase (PDE) activity. Similar to Ercc1d/− mice, age-related endothelium-dependent vasodilator dysfunction in XpdTTD animals was increased. To investigate the implications for human vascular disease, we explored associations between single nucleotide polymorphisms (SNPs) of selected nucleotide excision repair genes and arterial stiffness within the AortaGen Consortium, and found a significant association of a SNP (rs2029298) in the putative promoter region of DDB2 gene with carotid-femoral pulse wave velocity. Conclusions Mice with genomic instability recapitulate age-dependent vascular dysfunction as observed in animal models and in humans, but with an accelerated progression, as compared to wild type mice. In addition, we found associations between variations in human DNA repair genes and markers for vascular stiffness which is associated with aging. Our study supports the concept that genomic instability contributes importantly to the development of cardiovascular disease. PMID:22705887

Xeroderma pigmentosum genes and melanoma risk.

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Paszkowska-Szczur, K; Scott, R J; Serrano-Fernandez, P; Mirecka, A; Gapska, P; Górski, B; Cybulski, C; Maleszka, R; Sulikowski, M; Nagay, L; Lubinski, J; Dębniak, T

2013-09-01

Xeroderma pigmentosum is a rare autosomal recessive disease that is associated with a severe deficiency in nucleotide excision repair. The presence of a distinct the nucleotide excision repair (NER) mutation signature in melanoma suggests that perturbations in this critical repair process are likely to be involved with disease risk. We hypothesized that persons with polymorphic NER gene(s) are likely to have reduced NER activity and are consequently at an increased risk of melanoma development. We assessed the association between 94 SNPs within seven XP genes (XPA-XPG) and the melanoma risk in the Polish population. We genotyped 714 unselected melanoma patients and 1,841 healthy adults to determine if there were any polymorphisms differentially represented in the disease group. We found that a significantly decreased risk of melanoma was associated with the Xeroderma pigmentosum complementation (XPC) rs2228000_CT genotype (odds ratio [OR] = 0.15; p Xeroderma pigmentosum group D (XPD) showed a modest association between two haplotypes and a decrease in melanoma risk. There were no major differences between the prevalence of the XP polymorphisms among young or older patients with melanoma. Linkage disequilibrium of XPC: rs2228001, G1475A, G2061A, rs2228000 and rs3731062 was found. The data from our study support the notion that only XPC and XPD genes are associated with melanoma susceptibility. Copyright © 2013 UICC.

DNA Repair Gene Polymorphism and the Risk of Mitral Chordae Tendineae Rupture

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Aysel Kalayci Yigin

2015-01-01

Full Text Available Polymorphisms in Lys939Gln XPC gene may diminish DNA repair capacity, eventually increasing the risk of carcinogenesis. The aim of the present study was to evaluate the significance of polymorphism Lys939Gln in XPC gene in patients with mitral chordae tendinea rupture (MCTR. Twenty-one patients with MCTR and thirty-seven age and sex matched controls were enrolled in the study. Genotyping of XPC gene Lys939Gln polymorphism was carried out using polymerase chain reaction- (PCR- restriction fragment length polymorphism (RFLP. The frequencies of the heterozygote genotype (Lys/Gln-AC and homozygote genotype (Gln/Gln-CC were significantly different in MCTR as compared to control group, respectively (52.4% versus 43.2%, p=0.049; 38.15% versus 16.2%, p=0.018. Homozygote variant (Gln/Gln genotype was significantly associated with increased risk of MCTR (OR = 2.059; 95% CI: 1.097–3.863; p=0.018. Heterozygote variant (Lys/Gln genotype was also highly significantly associated with increased risk of MCTR (OR = 1.489; 95% CI: 1.041–2.129; p=0.049. The variant allele C was found to be significantly associated with MCTR (OR = 1.481; 95% CI: 1.101–1.992; p=0.011. This study has demonstrated the association of XPC gene Lys939Gln polymorphism with MCTR, which is significantly associated with increased risk of MCTR.

A expressão de genes reparadores do DNA nos tumores sincrônicos de câncer colorretal esporádico DNA repair gene expression in synchronic tumors of sporadic colorectal cancer

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Igor Proscurshim

2007-03-01

Full Text Available RACIONAL: Um dos mecanismos genéticos presentes em aproximadamente 80% dos pacientes com síndrome hereditária não-polipóide do câncer colorretal (HNPCC são os defeitos nos genes reparadores de DNA, como o MSH2, MSH6 e MLH1, onde os tumores sincrônicos são relativamente freqüentes. Já no câncer colorretal esporádico as lesões sincrônicas são raras. OBJETIVO: Verificar se o mesmo mecanismo genético presente no HNPCC está presente no câncer colorretal esporádico que apresentam com lesões sincrônicas. MÉTODOS: Foram incluídos no estudo todos os pacientes com câncer colorretal sincrônico não HNPCC. Imunoistoquímica com anticorpos para MSH2,MSH6, e MLH1 foi realizada para cada tumor. RESULTADOS: Todos os pacientes apresentaram expressão normal de MSH2 e MLH1. O único gene com imunoexpressão alterada foi o MSH6. CONCLUSÃO: Possivelmente outro mecanismo genético seja responsável pelo surgimento de dois tumores sincrônicos no câncer colorretal esporádico.BACKGROUND: Mismatch repair genes (such as MSH2, MLH1 and MSH6 mutations are present in over 80% of hereditary non-polyposis colorectal cancer (HNPCC tumors, which frequently exhibit synchronous lesions. Sporadic colorectal cancer is rarely associated with synchronous lesions. AIM: To investigate the role of mismatch repair gene mutation in synchronous sporadic colorectal cancer. METHODS: Patients with sporadic synchronous colorectal adenocarcinomas were included in the study. Immunohistochemistry was performed using MSH2, MLH1 and MSH6 antibodies. RESULTS: All patients had two synchoronous lesions. None of them had altered MSH2 or MLH1 expression. One patient had altered MSH6 expression in both tumors. CONCLUSION: Possibly, other molecular mechanisms are involved in carcinogenesis of sporadic synchronous colorectal cancer.

Polymorphic variations in the FANCA gene in high‐risk non‐BRCA1/2 breast cancer individuals from the French Canadian population

OpenAIRE

Litim, Nadhir; Labrie, Yvan; Desjardins, Sylvie; Ouellette, Geneviève; Plourde, Karine; Belleau, Pascal; Durocher, Francine

2012-01-01

The majority of genes associated with breast cancer susceptibility, including BRCA1 and BRCA2 genes, are involved in DNA repair mechanisms. Moreover, among the genes recently associated with an increased susceptibility to breast cancer, four are Fanconi Anemia (FA) genes: FANCD1/BRCA2, FANCJ/BACH1/BRIP1, FANCN/PALB2 and FANCO/RAD51C. FANCA is implicated in DNA repair and has been shown to interact directly with BRCA1. It has been proposed that the formation of FANCA/G (dependent upon the phos...

Chromosome End Repair and Genome Stability in Plasmodium falciparum

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Susannah F. Calhoun

2017-08-01

Full Text Available The human malaria parasite Plasmodium falciparum replicates within circulating red blood cells, where it is subjected to conditions that frequently cause DNA damage. The repair of DNA double-stranded breaks (DSBs is thought to rely almost exclusively on homologous recombination (HR, due to a lack of efficient nonhomologous end joining. However, given that the parasite is haploid during this stage of its life cycle, the mechanisms involved in maintaining genome stability are poorly understood. Of particular interest are the subtelomeric regions of the chromosomes, which contain the majority of the multicopy variant antigen-encoding genes responsible for virulence and disease severity. Here, we show that parasites utilize a competitive balance between de novo telomere addition, also called “telomere healing,” and HR to stabilize chromosome ends. Products of both repair pathways were observed in response to DSBs that occurred spontaneously during routine in vitro culture or resulted from experimentally induced DSBs, demonstrating that both pathways are active in repairing DSBs within subtelomeric regions and that the pathway utilized was determined by the DNA sequences immediately surrounding the break. In combination, these two repair pathways enable parasites to efficiently maintain chromosome stability while also contributing to the generation of genetic diversity.

PMS2 Involvement in Patients Suspected of Lynch Syndrome

NARCIS (Netherlands)

Niessen, Renee C.; Kleibeuker, Jan H.; Westers, Helga; Jager, Paul O. J.; Rozeveld, Dennie; Bos, Krista K.; Boersma-van Ek, Wytske; Hollema, Harry; Sijmons, Rolf H.; Hofstra, Robert M. W.

It is well-established that germline mutations in the mismatch repair genes MLH1, MSH2, and MSH6 cause Lynch syndrome. However, mutations in these three genes do not account for all Lynch syndrome (suspected) families. Recently, it was shown that germline mutations in another mismatch repair gene,

Human mismatch repair protein hMutLα is required to repair short slipped-DNAs of trinucleotide repeats.

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Panigrahi, Gagan B; Slean, Meghan M; Simard, Jodie P; Pearson, Christopher E

2012-12-07

Mismatch repair (MMR) is required for proper maintenance of the genome by protecting against mutations. The mismatch repair system has also been implicated as a driver of certain mutations, including disease-associated trinucleotide repeat instability. We recently revealed a requirement of hMutSβ in the repair of short slip-outs containing a single CTG repeat unit (1). The involvement of other MMR proteins in short trinucleotide repeat slip-out repair is unknown. Here we show that hMutLα is required for the highly efficient in vitro repair of single CTG repeat slip-outs, to the same degree as hMutSβ. HEK293T cell extracts, deficient in hMLH1, are unable to process single-repeat slip-outs, but are functional when complemented with hMutLα. The MMR-deficient hMLH1 mutant, T117M, which has a point mutation proximal to the ATP-binding domain, is defective in slip-out repair, further supporting a requirement for hMLH1 in the processing of short slip-outs and possibly the involvement of hMHL1 ATPase activity. Extracts of hPMS2-deficient HEC-1-A cells, which express hMLH1, hMLH3, and hPMS1, are only functional when complemented with hMutLα, indicating that neither hMutLβ nor hMutLγ is sufficient to repair short slip-outs. The resolution of clustered short slip-outs, which are poorly repaired, was partially dependent upon a functional hMutLα. The joint involvement of hMutSβ and hMutLα suggests that repeat instability may be the result of aberrant outcomes of repair attempts.

Putative Enzymes of UV Photoproduct Repair

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Cynthia J. Sakofsky

2011-01-01

Full Text Available In order to determine the biological relevance of two S. acidocaldarius proteins to the repair of UV photoproducts, the corresponding genes (Saci_1227 and Saci_1096 were disrupted, and the phenotypes of the resulting mutants were examined by various genetic assays. The disruption used integration by homologous recombination of a functional but heterologous pyrE gene, promoted by short sequences attached to both ends via PCR. The phenotypic analyses of the disruptants confirmed that ORF Saci_1227 encodes a DNA photolyase which functions in vivo, but they could not implicate ORF Saci_1096 in repair of UV- or other externally induced DNA damage despite its similarity to genes encoding UV damage endonucleases. The success of the gene-disruption strategy, which used 5′ extensions of PCR primers to target cassette integration, suggests potential advantages for routine construction of Sulfolobus strains.

Evaluation of possible occurrence of mutation in MMR repair system genes in resistant and sensitiveclinical strains of Mycobacterium tuberculosisby using sequencing method

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AmirPoyan Afzali

2016-07-01

Full Text Available Background:during recent years, the incidence and spread of drug resistance in Mycobacterium tuberculosis, the bacterium causing tuberculosis, has set this disease in World Health Organizationpriorities alignment of diseases like AIDS and hepatitis. Study of close examination of resistant and susceptible clinical strains genotypes is necessary to overcome drug resistance. Among the numerous repair systems, only there are limited number of encoding genes of DNA repair enzymes in Mycobacterium tuberculosis. Commonly these genes have been conserved and any changes among them likely increasethe mutation occurance due to the impossibility of correctionof spontaneous mutations insensitive strains of this bacteria.mut genes encodeDNA repairable enzymes.This study investigated the mutations in these genes and the effect of these mutations on tuberculosis drug resistance. Materials&Methods: In this study,of 29 available specimens,we were selected 8 susceptible strains and 21 resistantstrains andafter ordering appropriate primers and performing the proliferation reaction two types of amplicons produced which includingfragments of genes mut T2 and mut T4 and they were sent inorder to sequencing. Results:The results of chain reactionprimer represents an appropriate choice of primerswhich were investigated. Sequencing results showed that overall 73% of resistant strains that had been selected for study of mutT4gene, have no mutations in codons 48of mutT4 gene, and 70% of resistant strains have no GGA >>> CGA mutation at codon 58 of mutT2 gene. Conclusion: One of the strategies to overcome tuberculosis drug resistance is a close examination of genotypes of resistant and susceptible clinical strains. Results of this study was performedby examining changes in mut T2 and mut T4 gene sequence. The mutation in mut T2 always associated with mutation in mut T4, in this way, the first mutation may occurs in mut T4and after that, the second mutationmay occurs in mut T

Xeroderma pigmentosum complementation group C cells remove pyrimidine dimers selectively from the transcribed strand of active genes

International Nuclear Information System (INIS)

Venema, J.; van Hoffen, A.; Karcagi, V.; Natarajan, A.T.; van Zeeland, A.A.; Mullenders, L.H.

1991-01-01

The authors have measured the removal of UV-induced pyrimidine dimers from DNA fragments of the adenosine deaminase (ADA) and dihydrofolate reductase (DHFR) genes in primary normal human and xeroderma pigmentosum complementation group C (XP-C) cells. Using strand-specific probes, we show that in normal cells, preferential repair of the 5' part of the ADA gene is due to the rapid and efficient repair of the transcribed strand. Within 8 h after irradiation with UV at 10 J m-2, 70% of the pyrimidine dimers in this strand are removed. The nontranscribed strand is repaired at a much slower rate, with 30% dimers removed after 8 h. Repair of the transcribed strand in XP-C cells occurs at a rate indistinguishable from that in normal cells, but the nontranscribed strand is not repaired significantly in these cells. Similar results were obtained for the DHFR gene. In the 3' part of the ADA gene, however, both normal and XP-C cells perform fast and efficient repair of either strand, which is likely to be caused by the presence of transcription units on both strands. The factor defective in XP-C cells is apparently involved in the processing of DNA damage in inactive parts of the genome, including nontranscribed strands of active genes. These findings have important implications for the understanding of the mechanism of UV-induced excision repair and mutagenesis in mammalian cells

DNA repair: Dynamic defenders against cancer and aging

Energy Technology Data Exchange (ETDEWEB)

Fuss, Jill O.; Cooper, Priscilla K.

2006-04-01

(UV) component of sunlight. NER can be divided into two classes based on where the repair occurs. NER occurring in DNA that is not undergoing transcription (i.e., most of the genome) is called global genome repair (GGR or GGNER), while NER taking place in the transcribed strand of active genes is called transcription-coupled repair (TCR or TC-NER). We will explore NER in more detail below. Mismatch repair (MMR) is another type of excision repair that specifically removes mispaired bases resulting from replication errors. DNA damage can also result in breaks in the DNA backbone, in one or both strands. Single-strand breaks (SSBs) are efficiently repaired by a mechanism that shares common features with the later steps in BER. Double-strand breaks (DSBs) are especially devastating since by definition there is no intact complementary strand to serve as a template for repair, and even one unrepaired DSB can be lethal [3]. In cells that have replicated their DNA prior to cell division, the missing information can be supplied by the duplicate copy, or sister chromatid, and DSBs in these cells are faithfully repaired by homologous recombination involving the exchange of strands of DNA between the two copies. However, most cells in the body are non-dividing, and in these cells the major mechanism for repairing DSBs is by non-homologous end joining (NHEJ), which as the name implies involves joining two broken DNA ends together without a requirement for homologous sequence and which therefore has a high potential for loss of genetic information.

DNA repair in ultraviolet-irradiated spores of Bacillus subtilis

International Nuclear Information System (INIS)

Wang, T.C.V.

1976-01-01

It has been shown previously by others that at least two independent repair mechanisms are present in Bacillus subtilis for removing ''spore photoproduct'' from DNA of ultraviolet (254 nm)-irradiated spores after germination. One of these, designated as ''spore repair,'' is shown in this study to restore ''spore photoproduct'' to two thymine residues, leaving the DNA backbone intact at the end of the process in vivo. The circumstances under which this repair can occur and some characteristics of its energy requirements have been clarified. The second repair process is identified as excision repair, which can excise both ''spore photoproduct'' from DNA of irradiated spores and cyclobutane-type pyrimidine dimers from DNA of irradiated vegetative cells. In this study it is shown that the gene hcr 1 affects an enzyme activity for the incision step initiating this repair, while the gene hcr 42 affects a step subsequent to incision in the mechanism. In addition a third, independent repair system, termed ''germinative excision repair,'' is discovered and shown to be specific for excising only cyclobutane-type pyrimidine dimers but not ''spore photoproduct.'' This repair system is responsible for the observed high ultraviolet-resistance and temporary capacity for host cell reactivation on recently germinated spores of Bacillus subtilis HCR - strains

Repair promoted by plasmid pKM101 is different from SOS repair

International Nuclear Information System (INIS)

Goze, A.; Devoret, R.

1979-01-01

In E. coli K12 bacteria carrying plasmid pKM101, prophage lambda was induced at UV doses higher than in plasmid-less parental bacteria. UV-induced reactivation per se was less effective. Bacteria with pKM101 showed no alteration in their division cycle. Plasmid PKM101 coded for a constitutive error-prone repair different from the inducible error-prone repair called SOS repair. Plasmid pKM101 protected E. coli bacteria from UV damage but slightly sensitized them to X-ray lesions. Protection against UV damage was effective in mutant bacteria deficient in DNA excision-repair provided that the recA, lexA and uvrE genes were functional. Survival of phages lambda and S13 after UV irradiation was enhanced in bacteria carrying plasmid pKM101; phage lambda mutagenesis was also increased. Plasmid pKM101 repaired potentially lethal DNA lesions, although Wild-type DNA sequences may not necessarily be restored; hence the mutations observed are the traces of the original DNA lesions. (Auth.)

DNA repair and cancer

International Nuclear Information System (INIS)

Rathore, Shakuntla; Joshi, Pankaj Kumar; Gaur, Sudha

2012-01-01

DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecule that encode it's genome. In human cells, both normal metabolic activities and environmental factors such as UV light and radiation can cause DNA damage, resulting in as many one million individual molecular lesions per day. Many of these lesions cause structural damage to the DNA molecule and can alter or eliminate the cell's ability to transcribe the gene that the affected DNA encodes. Other lesions include potentially harmful mutation in cell's genome which affect the survival of it's daughter cells after it undergoes mitosis. As a consequence, the DNA repair process is constantly active as it responds to damage in the DNA structure. Inherited mutation that affect DNA repair genes are strongly associated with high cancer risks in humans. Hereditary non polyposis colorectal cancer (HNPCC) is strongly associated with specific mutation in the DNA mismatch repair pathway. BRCA1, BRCA2 two famous mutation conferring a hugely increased risk of breast cancer on carrier, are both associated with a large number of DNA repair pathway, especially NHEJ and homologous recombination. Cancer therapy procedures such as chemotherapy and radiotherapy work by overwhelming the capacity of the cell to repair DNA damage, resulting in cell death. Cells that are most rapidly dividing most typically cancer cells are preferentially affected. The side effect is that other non-cancerous but rapidly dividing cells such as stem cells in the bone marrow are also affected. Modern cancer treatment attempt to localize the DNA damage to cells and tissue only associated with cancer, either by physical means (concentrating the therapeutic agent in the region of the tumor) or by biochemical means (exploiting a feature unique to cancer cells in the body). (author)

Fructose-Rich Diet Affects Mitochondrial DNA Damage and Repair in Rats.

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Cioffi, Federica; Senese, Rosalba; Lasala, Pasquale; Ziello, Angela; Mazzoli, Arianna; Crescenzo, Raffaella; Liverini, Giovanna; Lanni, Antonia; Goglia, Fernando; Iossa, Susanna

2017-03-24

Evidence indicates that many forms of fructose-induced metabolic disturbance are associated with oxidative stress and mitochondrial dysfunction. Mitochondria are prominent targets of oxidative damage; however, it is not clear whether mitochondrial DNA (mtDNA) damage and/or its lack of repair are events involved in metabolic disease resulting from a fructose-rich diet. In the present study, we evaluated the degree of oxidative damage to liver mtDNA and its repair, in addition to the state of oxidative stress and antioxidant defense in the liver of rats fed a high-fructose diet. We used male rats feeding on a high-fructose or control diet for eight weeks. Our results showed an increase in mtDNA damage in the liver of rats fed a high-fructose diet and this damage, as evaluated by the expression of DNA polymerase γ, was not repaired; in addition, the mtDNA copy number was found to be significantly reduced. A reduction in the mtDNA copy number is indicative of impaired mitochondrial biogenesis, as is the finding of a reduction in the expression of genes involved in mitochondrial biogenesis. In conclusion, a fructose-rich diet leads to mitochondrial and mtDNA damage, which consequently may have a role in liver dysfunction and metabolic diseases.

Repair Mechanism of UV-damaged DNA in Xeroderma Pigmentosum | Center for Cancer Research

Science.gov (United States)

Xeroderma pigmentosum (XP) is a rare, inherited disorder characterized by extreme skin sensitivity to ultraviolet (UV) rays from sunlight. XP is caused by mutations in genes involved in nucleotide excision repair (NER) of damaged DNA. Normal cells are usually able to fix this damage before it leads to problems; however, the DNA damage is not repaired normally in patients with XP. As more abnormalities form in DNA, cells malfunction and eventually become cancerous or die. XP patients have more than a 10,000-fold increased risk of developing skin cancer. Kenneth Kraemer, M.D., in CCR’s Dermatology Branch, has been studying XP patients at the Clinical Center for more than 40 years.

Bioinformatics Analysis Reveals Genes Involved in the Pathogenesis of Ameloblastoma and Keratocystic Odontogenic Tumor.

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Santos, Eliane Macedo Sobrinho; Santos, Hércules Otacílio; Dos Santos Dias, Ivoneth; Santos, Sérgio Henrique; Batista de Paula, Alfredo Maurício; Feltenberger, John David; Sena Guimarães, André Luiz; Farias, Lucyana Conceição

2016-01-01

Pathogenesis of odontogenic tumors is not well known. It is important to identify genetic deregulations and molecular alterations. This study aimed to investigate, through bioinformatic analysis, the possible genes involved in the pathogenesis of ameloblastoma (AM) and keratocystic odontogenic tumor (KCOT). Genes involved in the pathogenesis of AM and KCOT were identified in GeneCards. Gene list was expanded, and the gene interactions network was mapped using the STRING software. "Weighted number of links" (WNL) was calculated to identify "leader genes" (highest WNL). Genes were ranked by K-means method and Kruskal-Wallis test was used (Preview data was used to corroborate the bioinformatics data. CDK1 was identified as leader gene for AM. In KCOT group, results show PCNA and TP53 . Both tumors exhibit a power law behavior. Our topological analysis suggested leader genes possibly important in the pathogenesis of AM and KCOT, by clustering coefficient calculated for both odontogenic tumors (0.028 for AM, zero for KCOT). The results obtained in the scatter diagram suggest an important relationship of these genes with the molecular processes involved in AM and KCOT. Ontological analysis for both AM and KCOT demonstrated different mechanisms. Bioinformatics analyzes were confirmed through literature review. These results may suggest the involvement of promising genes for a better understanding of the pathogenesis of AM and KCOT.

Identification and characterization of nuclear genes involved in photosynthesis in Populus

Science.gov (United States)

2014-01-01

Background The gap between the real and potential photosynthetic rate under field conditions suggests that photosynthesis could potentially be improved. Nuclear genes provide possible targets for improving photosynthetic efficiency. Hence, genome-wide identification and characterization of the nuclear genes affecting photosynthetic traits in woody plants would provide key insights on genetic regulation of photosynthesis and identify candidate processes for improvement of photosynthesis. Results Using microarray and bulked segregant analysis strategies, we identified differentially expressed nuclear genes for photosynthesis traits in a segregating population of poplar. We identified 515 differentially expressed genes in this population (FC ≥ 2 or FC ≤ 0.5, P photosynthesis by the nuclear genome mainly involves transport, metabolism and response to stimulus functions. Conclusions This study provides new genome-scale strategies for the discovery of potential candidate genes affecting photosynthesis in Populus, and for identification of the functions of genes involved in regulation of photosynthesis. This work also suggests that improving photosynthetic efficiency under field conditions will require the consideration of multiple factors, such as stress responses. PMID:24673936

True Lies: The Double Life of the Nucleotide Excision Repair Factors in Transcription and DNA Repair

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Nicolas Le May

2010-01-01

Full Text Available Nucleotide excision repair (NER is a major DNA repair pathway in eukaryotic cells. NER removes structurally diverse lesions such as pyrimidine dimers, arising upon UV irradiation or bulky chemical adducts, arising upon exposure to carcinogens and some chemotherapeutic drugs. NER defects lead to three genetic disorders that result in predisposition to cancers, accelerated aging, neurological and developmental defects. During NER, more than 30 polypeptides cooperate to recognize, incise, and excise a damaged oligonucleotide from the genomic DNA. Recent papers reveal an additional and unexpected role for the NER factors. In the absence of a genotoxic attack, the promoters of RNA polymerases I- and II-dependent genes recruit XPA, XPC, XPG, and XPF to initiate gene expression. A model that includes the growth arrest and DNA damage 45α protein (Gadd45α and the NER factors, in order to maintain the promoter of active genes under a hypomethylated state, has been proposed but remains controversial. This paper focuses on the double life of the NER factors in DNA repair and transcription and describes the possible roles of these factors in the RNA synthesis process.

Identification of new genes involved in human adipogenesis and fat storage.

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Jörn Söhle

Full Text Available Since the worldwide increase in obesity represents a growing challenge for health care systems, new approaches are needed to effectively treat obesity and its associated diseases. One prerequisite for advances in this field is the identification of genes involved in adipogenesis and/or lipid storage. To provide a systematic analysis of genes that regulate adipose tissue biology and to establish a target-oriented compound screening, we performed a high throughput siRNA screen with primary (preadipocytes, using a druggable siRNA library targeting 7,784 human genes. The primary screen showed that 459 genes affected adipogenesis and/or lipid accumulation after knock-down. Out of these hits, 333 could be validated in a secondary screen using independent siRNAs and 110 genes were further regulated on the gene expression level during adipogenesis. Assuming that these genes are involved in neutral lipid storage and/or adipocyte differentiation, we performed InCell-Western analysis for the most striking hits to distinguish between the two phenotypes. Beside well known regulators of adipogenesis and neutral lipid storage (i.e. PPARγ, RXR, Perilipin A the screening revealed a large number of genes which have not been previously described in the context of fatty tissue biology such as axonemal dyneins. Five out of ten axonemal dyneins were identified in our screen and quantitative RT-PCR-analysis revealed that these genes are expressed in preadipocytes and/or maturing adipocytes. Finally, to show that the genes identified in our screen are per se druggable we performed a proof of principle experiment using an antagonist for HTR2B. The results showed a very similar phenotype compared to knock-down experiments proofing the "druggability". Thus, we identified new adipogenesis-associated genes and those involved in neutral lipid storage. Moreover, by using a druggable siRNA library the screen data provides a very attractive starting point to identify anti

Implication of the E. coli K12 uvrA and recA genes in the repair of 8-methoxypsoralen-induced mono adducts and crosslinks on plasmid DNA

International Nuclear Information System (INIS)

Paramio, J.M.; Bauluz, C.; Vidania, R. de

1986-01-01

Genotoxicity of psoralen damages on plasmid DNA has been studied. pBR322 DNA was randomly modified with several concentrations of 8-methoxypsoralen plus 365 nm-UV light. After transformation into E. coli strains (wild-type, uvrA and recA) plasmid survival and mutagenesis were analyzed. To study the influence of the SOS response on plasmid recovery, preirradiation of the cells was performed. In absence of cell preirradiation, crosslinks were not repaired in any strain. Mono adducts were also lethal but in part removed by the excision-repair pathway. Preirradiation of the cells significantly. increased plasmid recovery in recA+ celia. In uvrA- only the mutagenic pathway seemed to be involved in the repair of the damaged DNA. Wild type strain showed the highest increase in plasmid survival, involving the repair of mono adducts and some fraction of crosslinks mainly through an error-free repair pathway. This suggests an enhancement of the excision repair promoted by the induction of SOS functions. (Author) 32 refs

Aspects of DNA repair and nucleotide pool imbalance

Energy Technology Data Exchange (ETDEWEB)

Holliday, R.

1985-01-01

Evidence that optimum repair depends on adequate pools of deoxynucleotide triphosphates (dNTPs) comes from the study of pyrimidine auxotrophs of Ustilago maydis. These strains are sensitive to UV light and X-rays, and for pyr1-1 it has been shown that the intracellular concentration of dTTP is reduced about 7-fold. The survival curve of pyr1-1 after UV-treatment, and split dose experiments with wild-type cells, provide evidence for an inducible repair mechanism, which probably depends on genetic recombination. Although inducible repair saves cellular resources, it has the disadvantage of becoming ineffective at doses which are high enough to inactivate the repressed structural gene(s) for repair enzymes. It is clear that a wide variety of repair mechanisms have evolved to remove lesions which arise either spontaneously or as a result of damage from external agents. Nevertheless, it would be incorrect to assume that all species require all possible pathways of repair. It is now well established that the accuracy of DNA and protein synthesis depends on proof-reading or editing mechanisms. Optimum accuracy levels will evolve from the balance between error avoidance in macromolecular synthesis and physiological efficiency in growth and propagation.

A history of the DNA repair and mutagenesis field: The discovery of base excision repair.

Science.gov (United States)

Friedberg, Errol C

2016-01-01

This article reviews the early history of the discovery of an DNA repair pathway designated as base excision repair (BER), since in contrast to the enzyme-catalyzed removal of damaged bases from DNA as nucleotides [called nucleotide excision repair (NER)], BER involves the removal of damaged or inappropriate bases, such as the presence of uracil instead of thymine, from DNA as free bases. Copyright © 2015. Published by Elsevier B.V.

DNA mismatch repair gene MLH1 induces apoptosis in prostate cancer cells.

Science.gov (United States)

Fukuhara, Shinichiro; Chang, Inik; Mitsui, Yozo; Chiyomaru, Takeshi; Yamamura, Soichiro; Majid, Shahana; Saini, Sharanjot; Hirata, Hiroshi; Deng, Guoren; Gill, Ankurpreet; Wong, Darryn K; Shiina, Hiroaki; Nonomura, Norio; Dahiya, Rajvir; Tanaka, Yuichiro

2014-11-30

Mismatch repair (MMR) enzymes have been shown to be deficient in prostate cancer (PCa). MMR can influence the regulation of tumor development in various cancers but their role on PCa has not been investigated. The aim of the present study was to determine the functional effects of the mutL-homolog 1 (MLH1) gene on growth of PCa cells. The DU145 cell line has been established as MLH1-deficient and thus, this cell line was utilized to determine effects of MLH1 by gene expression. Lack of MLH1 protein expression was confirmed by Western blotting in DU145 cells whereas levels were high in normal PWR-1E and RWPE-1 prostatic cells. MLH1-expressing stable transfectant DU145 cells were then created to characterize the effects this MMR gene has on various growth properties. Expression of MLH1 resulted in decreased cell proliferation, migration and invasion properties. Lack of cell growth in vivo also indicated a tumor suppressive effect by MLH1. Interestingly, MLH1 caused an increase in apoptosis along with phosphorylated c-Abl, and treatment with MLH1 siRNAs countered this effect. Furthermore, inhibition of c-Abl with STI571 also abrogated the effect on apoptosis caused by MLH1. These results demonstrate MLH1 protects against PCa development by inducing c-Abl-mediated apoptosis.

Somatic mutations in mismatch repair genes in sporadic gastric carcinomas are not a cause but a consequence of the mutator phenotype

NARCIS (Netherlands)

Pinto, Mafalda; Wub, Ying; Mensink, Rob G. J.; Cirnes, Luis; Seruca, Raquel; Hofstra, Robert M. W.

2008-01-01

In hereditary nonpolyposis colorectal cancer (HNPCC), patients' mismatch repair (MMR) gene mutations cause MMR deficiency, leading to microsatellite instability (MSI-H). MSI-H is also found in a substantial fraction of sporadic gastric carcinomas (SGC), mainly due to MLH1 promoter hypermethylation,

Cycling with BRCA2 from DNA repair to mitosis

International Nuclear Information System (INIS)

Lee, Hyunsook

2014-01-01

Genetic integrity in proliferating cells is guaranteed by the harmony of DNA replication, appropriate DNA repair, and segregation of the duplicated genome. Breast cancer susceptibility gene BRCA2 is a unique tumor suppressor that is involved in all three processes. Hence, it is critical in genome maintenance. The functions of BRCA2 in DNA repair and homology-directed recombination (HDR) have been reviewed numerous times. Here, I will briefly go through the functions of BRCA2 in HDR and focus on the emerging roles of BRCA2 in telomere homeostasis and mitosis, then discuss how BRCA2 exerts distinct functions in a cell-cycle specific manner in the maintenance of genomic integrity. - Highlights: • BRCA2 is a multifaceted tumor suppressor and is crucial in genetic integrity. • BRCA2 exerts distinct functions in cell cycle-specific manner. • Mitotic kinases regulate diverse functions of BRCA2 in mitosis and cytokinesis

Cycling with BRCA2 from DNA repair to mitosis

Energy Technology Data Exchange (ETDEWEB)

Lee, Hyunsook, E-mail: HL212@snu.ac.kr

2014-11-15

Genetic integrity in proliferating cells is guaranteed by the harmony of DNA replication, appropriate DNA repair, and segregation of the duplicated genome. Breast cancer susceptibility gene BRCA2 is a unique tumor suppressor that is involved in all three processes. Hence, it is critical in genome maintenance. The functions of BRCA2 in DNA repair and homology-directed recombination (HDR) have been reviewed numerous times. Here, I will briefly go through the functions of BRCA2 in HDR and focus on the emerging roles of BRCA2 in telomere homeostasis and mitosis, then discuss how BRCA2 exerts distinct functions in a cell-cycle specific manner in the maintenance of genomic integrity. - Highlights: • BRCA2 is a multifaceted tumor suppressor and is crucial in genetic integrity. • BRCA2 exerts distinct functions in cell cycle-specific manner. • Mitotic kinases regulate diverse functions of BRCA2 in mitosis and cytokinesis.

The light gene of Drosophila melanogaster encodes a homologue of VPS41, a yeast gene involved in cellular-protein trafficking.

Science.gov (United States)

Warner, T S; Sinclair, D A; Fitzpatrick, K A; Singh, M; Devlin, R H; Honda, B M

1998-04-01

Mutations in a number of genes affect eye colour in Drosophila melanogaster; some of these "eye-colour" genes have been shown to be involved in various aspects of cellular transport processes. In addition, combinations of viable mutant alleles of some of these genes, such as carnation (car) combined with either light (lt) or deep-orange (dor) mutants, show lethal interactions. Recently, dor was shown to be homologous to the yeast gene PEP3 (VPS18), which is known to be involved in intracellular trafficking. We have undertaken to extend our earlier work on the lt gene, in order to examine in more detail its expression pattern and to characterize its gene product via sequencing of a cloned cDNA. The gene appears to be expressed at relatively high levels in all stages and tissues examined, and shows strong homology to VPS41, a gene involved in cellular-protein trafficking in yeast and higher eukaryotes. Further genetic experiments also point to a role for lt in transport processes: we describe lethal interactions between viable alleles of lt and dor, as well as phenotypic interactions (reductions in eye pigment) between allels of lt and another eye-colour gene, garnet (g), whose gene product has close homology to a subunit of the human adaptor complex, AP-3.

Biochemical mechanisms involved in the endotoxin-induced type II cell hyperplasia in F344 rat lung

International Nuclear Information System (INIS)

Tesfaigzi, J.; Johnson, N.F.; Lechner, J.F.

1994-01-01

Proliferative lesions and pulmonary epithelial neoplasms induced in the rat by plutonium inhalation have been shown to be of type II cell origin. Defining the gene changes responsible for the development of the type II proliferative lesions would help to elucidate the genetic events involved in the expansion of initiated type II cells into fully transformed tumor cells. One problem in identifying these gene alterations is dissociating changes in gene expression linked to cell replication or repair from those involved in tumor initiation and progression. The long-term goals of these investigations are to first develop and characterize a model of transient type II cell hyperplasia. Second, changes in gene expression associated with remodeling epithelium will be compared to gene changes exhibited by the 239 Pu-induced hyperplastic lesions

48 CFR 1371.118 - Changes-ship repair.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Changes-ship repair. 1371.118 Section 1371.118 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE DEPARTMENT SUPPLEMENTAL REGULATIONS ACQUISITIONS INVOLVING SHIP CONSTRUCTION AND SHIP REPAIR Provisions and Clauses 1371.118 Changes—ship repair. Insert clause...

A massive parallel sequencing workflow for diagnostic genetic testing of mismatch repair genes

Science.gov (United States)

Hansen, Maren F; Neckmann, Ulrike; Lavik, Liss A S; Vold, Trine; Gilde, Bodil; Toft, Ragnhild K; Sjursen, Wenche

2014-01-01

The purpose of this study was to develop a massive parallel sequencing (MPS) workflow for diagnostic analysis of mismatch repair (MMR) genes using the GS Junior system (Roche). A pathogenic variant in one of four MMR genes, (MLH1, PMS2, MSH6, and MSH2), is the cause of Lynch Syndrome (LS), which mainly predispose to colorectal cancer. We used an amplicon-based sequencing method allowing specific and preferential amplification of the MMR genes including PMS2, of which several pseudogenes exist. The amplicons were pooled at different ratios to obtain coverage uniformity and maximize the throughput of a single-GS Junior run. In total, 60 previously identified and distinct variants (substitutions and indels), were sequenced by MPS and successfully detected. The heterozygote detection range was from 19% to 63% and dependent on sequence context and coverage. We were able to distinguish between false-positive and true-positive calls in homopolymeric regions by cross-sample comparison and evaluation of flow signal distributions. In addition, we filtered variants according to a predefined status, which facilitated variant annotation. Our study shows that implementation of MPS in routine diagnostics of LS can accelerate sample throughput and reduce costs without compromising sensitivity, compared to Sanger sequencing. PMID:24689082

Measurement of DNA repair deficiency in workers exposed to benzene

International Nuclear Information System (INIS)

Hallberg, L.M.; Au, W.W.; El Zein, R.; Grossman, L.

1996-01-01

We hypothesize that chronic exposure to environmental toxicants can induce genetic damage causing DNA repair deficiencies and leading to the postulated mutator phenotype of carcinogenesis. To test our hypothesis, a host cell reactivation (HCR) assay was used in which pCMVcat plasmids were damaged with UV light (175, 350 J/m 2 UV light), inactivating the chloramphenicol acetyltransferase reporter gene, and then transfected into lymphocytes. Transfected lymphocytes were therefore challenged to repair the damaged plasmids, reactivating the reporter gene. Xeroderma pigmentosum (XP) and Gaucher cell lines were used as positive and negative controls for the HCR assay. The Gaucher cell line repaired normally but XP cell lines demonstrated lower repair activity. Additionally, the repair activity of the XP heterozygous cell line showed intermediate repair compared to the homozygous XP and Gaucher cells. We used HCR to measure the effects of benzene exposure on 12 exposed and 8 nonexposed workers from a local benzene plant. Plasmids 175 J/m 2 and 350 J/m 2 were repaired with a mean frequency of 66% and 58%, respectively, in control workers compared to 71% and 62% in exposed workers. Conversely, more of the exposed workers were grouped into the reduced repair category than controls. These differences in repair capacity between exposed and control workers were, however, not statistically significant. The lack of significant differences between the exposed and control groups may be due to extremely low exposure to benzene (<0.3 ppm), small population size, or a lack of benzene genotoxicity at these concentrations. These results are consistent with a parallel hprt gene mutation assay. 26 refs., 4 figs., 2 tabs

Identification of Phytophthora sojae genes involved in asexual ...

Indian Academy of Sciences (India)

ual sporulation or germination. But molecular details about asexual spore development in P. sojae are limited (Tyler et al. 2006). In the present study, to understand the molecular basis of asexual spore development in P. sojae, we investigated gene expression changes involved in asexual sporulation after ul- traviolet (UV) ...

Mutations in DNA repair genes are associated with the Haarlem lineage of Mycobacterium tuberculosis independently of their antibiotic resistance.

Science.gov (United States)

Olano, Juanita; López, Beatriz; Reyes, Alejandro; Lemos, María del Pilar; Correa, Nidia; Del Portillo, Patricia; Barrera, Lucia; Robledo, Jaime; Ritacco, Viviana; Zambrano, María Mercedes

2007-11-01

The analysis of the DNA repair genes ogt and ung was carried out in 117 Mycobacterium tuberculosis clinical isolates from Argentina and Colombia in order to explore correlation between mutations in these genes and multi-drug resistance. With the exception of two Beijing family isolates, the rest of the strains harbored either two wild-type or two mutant alleles with identical single nucleotide polymorphisms (SNPs) in each gene (ogt44 and ung501). These ogt44 and ung501 mutations were not associated with multi-drug resistance and occurred simultaneously in circulating Haarlem genotype M. tuberculosis strains. We therefore propose the use of these markers as tools in phylogenetic and epidemiologic studies.

Genotoxic thresholds, DNA repair, and susceptibility in human populations

International Nuclear Information System (INIS)

Jenkins, Gareth J.S.; Zair, Zoulikha; Johnson, George E.; Doak, Shareen H.

2010-01-01

considered. In terms of industrial exposures to known mutagens, knowing the dose relationships and protective mechanisms involved, offers the possibility of screening workers for susceptibility to mutation through examining DNA repair gene polymorphisms. Hence, thresholds may exist for certain mutagens, but there will undoubtedly be human subpopulations who are more at risk from low dose exposures than others and who should not be exposed, if possible. By studying polymorphisms in DNA repair genes, susceptible individuals may be identified, and additional safety factors appropriately targeted to these populations.

Placental promoter methylation of DNA repair genes and prenatal exposure to particulate air pollution: an ENVIRONAGE cohort study

Directory of Open Access Journals (Sweden)

Kristof Y Neven, MSc

2018-04-01

Full Text Available Summary: Background: Exposure to particulate air pollution has been linked with risk of carcinogenesis. Damage to repair pathways might have long-term adverse health effects. We aimed to investigate the association of prenatal exposure to air pollution with placental mutation rate and the DNA methylation of key placental DNA repair genes. Methods: This cohort study used data from the ongoing ENVironmental Influence ON early AGEing (ENVIRONAGE birth cohort, which enrols pairs of mothers and neonates (singleton births only at the East-Limburg Hospital (Genk, Belgium. Placental DNA samples were collected after birth. We used bisulfite-PCR-pyrosequencing to investigate the mutation rate of Alu (a marker for overall DNA mutation and DNA methylation in the promoter genes of key DNA repair and tumour suppressor genes (APEX1, OGG1, PARP1, ERCC1, ERCC4, p53, and DAPK1. We used a high-resolution air pollution model to estimate exposure to particulate matter with a diameter less than 2·5 μm (PM2·5, black carbon, and NO2 over the entire pregnancy on the basis of maternal address. Alu mutation was analysed with a linear regression model, and methylation values of the selected genes were analysed in mixed-effects models. Effect estimates are presented as the relative percentage change in methylation for an ambient air pollution increment of one IQR (ie, the difference between the first and third quartiles of exposure in the entire cohort. Findings: 500 biobanked placental DNA samples were randomly selected from 814 pairs of mothers and neonates who were recruited to the cohort between Feb 1, 2010, and Dec 31, 2014, of which 463 samples met the pyrosequencing quality control criteria. IQR exposure increments were 3·84 μg/m3 for PM2·5, 0·36 μg/m3 for black carbon, and 5·34 μg/m3 for NO2. Among these samples, increased Alu mutation rate was associated with greater exposure to PM2·5 (r=0·26, p<0·0001 and black carbon (r=0·33, p<0·0001, but not NO2

Genes and Gut Bacteria Involved in Luminal Butyrate Reduction Caused by Diet and Loperamide.

Science.gov (United States)

Hwang, Nakwon; Eom, Taekil; Gupta, Sachin K; Jeong, Seong-Yeop; Jeong, Do-Youn; Kim, Yong Sung; Lee, Ji-Hoon; Sadowsky, Michael J; Unno, Tatsuya

2017-11-28

Unbalanced dietary habits and gut dysmotility are causative factors in metabolic and functional gut disorders, including obesity, diabetes, and constipation. Reduction in luminal butyrate synthesis is known to be associated with gut dysbioses, and studies have suggested that restoring butyrate formation in the colon may improve gut health. In contrast, shifts in different types of gut microbiota may inhibit luminal butyrate synthesis, requiring different treatments to restore colonic bacterial butyrate synthesis. We investigated the influence of high-fat diets (HFD) and low-fiber diets (LFD), and loperamide (LPM) administration, on key bacteria and genes involved in reduction of butyrate synthesis in mice. MiSeq-based microbiota analysis and HiSeq-based differential gene analysis indicated that different types of bacteria and genes were involved in butyrate metabolism in each treatment. Dietary modulation depleted butyrate kinase and phosphate butyryl transferase by decreasing members of the Bacteroidales and Parabacteroides . The HFD also depleted genes involved in succinate synthesis by decreasing Lactobacillus . The LFD and LPM treatments depleted genes involved in crotonoyl-CoA synthesis by decreasing Roseburia and Oscilllibacter . Taken together, our results suggest that different types of bacteria and genes were involved in gut dysbiosis, and that selected treatments may be needed depending on the cause of gut dysfunction.

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)

Resistance to radiation, recombination, repair of DNA and chromosome organisation

Energy Technology Data Exchange (ETDEWEB)

Fletcher, H L [East Anglia Univ., Norwich (UK). School of Biological Sciences

1981-01-01

The model advanced here proposes that death is caused by destructive lesions, mainly double-strand breaks, in all the inter-repairable copies so close together that recombination repair cannot function. Death is related to the exponential of dose where r is the number of copies of the genome. A graph of ln(-ln survival) against ln dose is used to produce a linear dose-survival relationship, the slope of which gives the number of inter-repairable copies of the genome (= number of hits per lethal event). In Ustilago maydis it seems that unless all the chromatids are broken within a few thousand base pairs all ds breaks are repaired. The size of this critical target is similar to the size of a gene. Meiotic pairing in fungi starts outside the genes, and it is therefore suggested that specific pairing sites between genes define the ends of the targets. The model also describes the radiation-induced death of Micrococcus radiodurans and Sacchromyces cerevisiae. Cultured mammalian cells also show a linear ln(-ln survival)/ln dose relationship with a slope of 1.5 showing that both 1st and 2nd order killing occured. Sublethal radiation induces recombination in heterozygous diploid U. maydis proportional to the square of the dose. Sister-chromatid repair is preferred. Polyploid yeast can only use pairs of chromosomes for repair, showing that chromosome pairing is required for recombination repair, and mitotic pairing is restricted to bivalents in the same way that meiotic pairing is.

Efficacy of DNA double-strand breaks repair in breast cancer is decreased in carriers of the variant allele of the UBC9 gene c.73G>A polymorphism

International Nuclear Information System (INIS)

Synowiec, Ewelina; Krupa, Renata; Morawiec, Zbigniew; Wasylecka, Maja; Dziki, Lukasz; Morawiec, Jan; Blasiak, Janusz; Wozniak, Katarzyna

2010-01-01

UBC9 (E2) SUMO conjugating enzyme plays an important role in the maintenance of genome stability and integrity. In the present work we examined the association between the c.73G>A (Val25Met) polymorphism of the UBC9 gene (rs11553473) and efficacy of DNA double-strand breaks (DSBs) repair (DRE) in breast cancer patients. We determined the level of endogenous (basal) and exogenous (induced by γ-irradiation) DSBs and efficacy of their repair in peripheral blood lymphocytes of 57 breast cancer patients and 70 healthy individuals. DNA damage and repair were studied by neutral comet assay. Genotypes were determined in DNA from peripheral blood lymphocytes by allele-specific PCR (ASO-PCR). We also correlated genotypes with the clinical characteristics of breast cancer patients. We observed a strong association between breast cancer occurrence and the variant allele carried genotypes in patients with elevated level of basal as well as induced DNA damage (OR 6.74, 95% CI 2.27-20.0 and OR 5.33, 95% CI 1.81-15.7, respectively). We also found statistically significant (p A polymorphism of the UBC9 gene in breast cancer patients. Carriers of variant allele have decreased DNA DRE as compared to wild type genotype carriers. We did not find any association with the UBC9 gene polymorphism and estrogen and progesterone receptor status. The variant allele of the UBC9 gene polymorphism was strongly inversely related to HER negative breast cancer patients (OR 0.03, 95% CI 0.00-0.23). Our results suggest that the c.73G>A polymorphism of the UBC9 gene may affect DNA DSBs repair efficacy in breast cancer patients.

Component-Level Electronic-Assembly Repair (CLEAR) System Architecture

Science.gov (United States)

Oeftering, Richard C.; Bradish, Martin A.; Juergens, Jeffrey R.; Lewis, Michael J.; Vrnak, Daniel R.

2011-01-01

This document captures the system architecture for a Component-Level Electronic-Assembly Repair (CLEAR) capability needed for electronics maintenance and repair of the Constellation Program (CxP). CLEAR is intended to improve flight system supportability and reduce the mass of spares required to maintain the electronics of human rated spacecraft on long duration missions. By necessity it allows the crew to make repairs that would otherwise be performed by Earth based repair depots. Because of practical knowledge and skill limitations of small spaceflight crews they must be augmented by Earth based support crews and automated repair equipment. This system architecture covers the complete system from ground-user to flight hardware and flight crew and defines an Earth segment and a Space segment. The Earth Segment involves database management, operational planning, and remote equipment programming and validation processes. The Space Segment involves the automated diagnostic, test and repair equipment required for a complete repair process. This document defines three major subsystems including, tele-operations that links the flight hardware to ground support, highly reconfigurable diagnostics and test instruments, and a CLEAR Repair Apparatus that automates the physical repair process.

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

Adaptive response to ionizing radiation in normal human skin fibroblasts. Enhancement of DNA repair rate and modulation of gene expression

International Nuclear Information System (INIS)

Toledo, S.M. de; Mitchel, R.E.J.; Azzam, E.; Ottawa Univ., ON; Raaphorst, G.P.

1994-01-01

Low doses and dose rates of ionizing radiation enhance the rate of DNA repair in human fibroblasts and protect the cells against radiation-induced micronucleus formation. Chronic exposures reduce the mRNA levels of the genes topoisomerase II and FACC-1 (Fanconi's anemia, group C). (authors). 11 refs., 1 tab., 2 figs

Gene therapy: An overview

Directory of Open Access Journals (Sweden)

Sudip Indu

2013-01-01

Full Text Available Gene therapy "the use of genes as medicine" involves the transfer of a therapeutic or working copy of a gene into specific cells of an individual in order to repair a faulty gene copy. The technique may be used to replace a faulty gene, or to introduce a new gene whose function is to cure or to favorably modify the clinical course of a condition. The objective of gene therapy is to introduce new genetic material into target cells while causing no damage to the surrounding healthy cells and tissues, hence the treatment related morbidity is decreased. The delivery system includes a vector that delivers a therapeutic gene into the patient′s target cell. Functional proteins are created from the therapeutic gene causing the cell to return to a normal stage. The vectors used in gene therapy can be viral and non-viral. Gene therapy, an emerging field of biomedicine, is still at infancy and much research remains to be done before this approach to the treatment of condition will realize its full potential.

Identification of genes involved in DNA replication of the Autographa californica baculovirus

NARCIS (Netherlands)

Kool, M.; Ahrens, C. H.; Goldbach, R. W.; Rohrmann, G. F.; Vlak, J. M.

1994-01-01

By use of a transient replication assay, nine genes involved in DNA replication were identified in the genome of the Autographa californica baculovirus. Six genes encoding helicase, DNA polymerase, IE-1, LEF-1, LEF-2, and LEF-3 are essential for DNA replication while three genes encoding P35, IE-2,

Gonadotropin-releasing hormone regulates expression of the DNA damage repair gene, Fanconi anemia A, in pituitary gonadotroph cells.

Science.gov (United States)

Larder, Rachel; Chang, Lynda; Clinton, Michael; Brown, Pamela

2004-09-01

Gonadal function is critically dependant on regulated secretion of the gonadotropin hormones from anterior pituitary gonadotroph cells. Gonadotropin biosynthesis and release is triggered by the binding of hypothalamic GnRH to GnRH receptor expressed on the gonadotroph cell surface. The repertoire of regulatory molecules involved in this process are still being defined. We used the mouse L beta T2 gonadotroph cell line, which expresses both gonadotropin hormones, as a model to investigate GnRH regulation of gene expression and differential display reverse transcription-polymerase chain reaction (RT-PCR) to identify and isolate hormonally induced changes. This approach identified Fanconi anemia a (Fanca), a gene implicated in DNA damage repair, as a differentially expressed transcript. Mutations in Fanca account for the majority of cases of Fanconi anemia (FA), a recessively inherited disease identified by congenital defects, bone marrow failure, infertility, and cancer susceptibility. We confirmed expression and hormonal regulation of Fanca mRNA by quantitative RT-PCR, which showed that GnRH induced a rapid, transient increase in Fanca mRNA. Fanca protein was also acutely upregulated after GnRH treatment of L beta T2 cells. In addition, Fanca gene expression was confined to mature pituitary gonadotrophs and adult mouse pituitary and was not expressed in the immature alpha T3-1 gonadotroph cell line. Thus, this study extends the expression profile of Fanca into a highly specialized endocrine cell and demonstrates hormonal regulation of expression of the Fanca locus. We suggest that this regulatory mechanism may have a crucial role in the GnRH-response mechanism of mature gonadotrophs and perhaps the etiology of FA.

The promotion of cartilage defect repair using adenovirus mediated Sox9 gene transfer of rabbit bone marrow mesenchymal stem cells.

Science.gov (United States)

Cao, Lei; Yang, Fei; Liu, Guangwang; Yu, Degang; Li, Huiwu; Fan, Qiming; Gan, Yaokai; Tang, Tingting; Dai, Kerong

2011-06-01

Although Sox9 is essential for chondrogenic differentiation and matrix production, its application in cartilage tissue engineering has been rarely reported. In this study, the chondrogenic effect of Sox9 on bone marrow mesenchymal stem cells (BMSCs) in vitro and its application in articular cartilage repair in vivo were evaluated. Rabbit BMSCs were transduced with adenoviral vector containing Sox9. Toluidine blue, safranin O staining and real-time PCR were performed to check chondrogenic differentiation. The results showed that Sox9 could induce chondrogenesis of BMSCs both in monolayer and on PGA scaffold effectively. The rabbit model with full-thickness cartilage defects was established and then repaired by PGA scaffold and rabbit BMSCs with or without Sox9 transduction. HE, safranin O staining and immunohistochemistry were used to assess the repair of defects by the complex. Better repair, including more newly-formed cartilage tissue and hyaline cartilage-specific extracellular matrix and greater expression of several chondrogenesis marker genes were observed in PGA scaffold and BMSCs with Sox9 transduction, compared to that without transduction. Our findings defined the important role of Sox9 in the repair of cartilage defects in vivo and provided evidence that Sox9 had the potential and advantage in the application of tissue engineering. Copyright © 2011 Elsevier Ltd. All rights reserved.