Sample records for 修复 (repair)

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X-ray response of Chinese hamster ovary cells during the latter part of G2.

Griffiths, T D

The ability of Chinese hamster ovary (CHO) cells to repair x-radiation damage during the transit from the late G2 to early M cell cycle stages was investigated by conventional dose-fractionation techniques. Despite their relatively high radiation sensitivity, CHO cells positioned in late G2 exhibit ...

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V(D)J recombination in mammalian cell mutants defective in DNA double-strand break repair.

Pergola, F; Lieber, M R; Zdzienicka, M Z

V(D)J recombination has been examined in several X-ray-sensitive and double-strand break repair-deficient Chinese hamster cell mutants. Signal joint formation was affected in four mutants (xrs 5, XR-1, V-3, and XR-V9B cells, representing complementation groups 1 through 4, respectively) defective in...

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Two Forms of Repair of DNA in Mammalian Cells following Irradiation

Elkind, M. M.; Kamper, C.

When Chinese hamster cells are lysed on top of an alkaline sucrose gradient, in time a fairly discrete DNA-containing molecular species is released from an apparently more complex material. Small doses of X-radiation speed the resolution of this complex while large doses degrade the material release...

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The p53 status of Chinese hamster V79 cells frequently used for studies on DNA damage and DNA repair.

Chaung, W; Boorstein, R J; Mi, L J

Chinese hamster lung fibroblast V79 cells have been widely used in studies of DNA damage and DNA repair. Since the p53 gene is involved in normal responses to DNA damage, we have analyzed the molecular genetics and functional status of p53 in V79 cells and primary Chinese hamster embryonic fibroblas...

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The ATF/CREB transcription factor-binding site in the polymerase beta promoter mediates the positive effect of N-methyl-N'-nitro-N-nitrosoguanidine on transcription.

Fornace, A J; Kedar, P S; Englander, E W; Widen, S G; Wilson, S H

DNA polymerase beta (pol beta) is a constitutively expressed DNA repair enzyme in vertebrate cells. Yet, it had been shown previously that the pol beta mRNA level increases in Chinese hamster ovary (CHO) cells within 4 h after treatment with several monofunctional DNA damaging agents, notably, N-met...

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Poly(ADP-ribose) polymerase (PARP) plays an important role in a number of cellular processes including DNA repair. Since poly(ADP-ribosyl)ation occurs in response to radiation- or drug-induced DNA damage, inhibitors of the enzyme may enhance the antitumour activity of radiotherapy or cytotoxic drug ...

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Strand specificity for UV-induced DNA repair and mutations in the Chinese hamster HPRT gene.

van Zeeland, A A; van Hoffen, A; Vrieling, H; van Rooyen, M L; Venema, J; Menichini, P; Mullenders, L H; Zdzienicka, M Z

DNA excision repair modulates the mutagenic effect of many genotoxic agents. The recently observed strand specificity for removal of UV-induced cyclobutane dimers from actively transcribed genes in mammalian cells could influence the nature and distribution of mutations in a particular gene. To inve...

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Single strand breakage and repair in eukaryotic DNA as assayed by S1 nuclease.

Sheridan, R B; Huang, P C

A sensitive new approach for measuring the repair of single strand breaks in DNA induced by low doses of gamma irradiation was tested in cultured fibroblasts from Chinese hamster lung, human afflicted with ataxia telangiectasia or Fanconi's anemia and in normal cells of early and late passages. The ...

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Sequence variations in DNA repair gene XPC is associated with lung cancer risk in a Chinese population: a case-control study

Qian, Ji; Yuan, Wentao; Yang, Lin; Wei, Qingyi; Shao, Minhua; Shen, Hongbing; Ma, Hongxia; Liu, Hongliang; Yang, Xiaobo

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Role of the human ERCC-1 gene in gene-specific repair of cisplatin-induced DNA damage.

Larminat, F; Bohr, V A

The human excision repair gene ERCC-1 gene restores normal resistance to UV and mitomycin C in excision repair deficient chinese hamster ovary cells of complementation group 1. To investigate the involvement of the ERCC-1 gene in gene-specific repair of bulky lesions, we have studied the removal of ...

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Role of DNA repair in mutagenesis of Chinese hamster ovary cells by 7-bromomethylbenz[a]anthracene.

Dillehay, L E; Thompson, L H; Carrano, A V; Brookman, K W

The role of DNA repair in mutagenesis was studied in normal, repair-proficient Chinese hamster ovary cells and in two mutant strains that are deficient in excision repair. By using the mutagen 7-bromomethylbenz[a]anthracene (7-BrMeBA) and the technique of alkaline elution of DNA, the mutants were fo...

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Repair-deficient xeroderma pigmentosum cells made UV light resistant by fusion with X-ray-inactivated Chinese hamster cells.

Karentz, D; Cleaver, J E

Xeroderma pigmentosum (XP) is an autosomal recessive human disease, characterized by an extreme sensitivity to sunlight, caused by the inability of cells to repair UV light-induced damage to DNA. Cell fusion was used to transfer fragments of Chinese hamster ovary (CHO) chromosomes into XP cells. The...

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Repair of N-methylpurines in specific DNA sequences in Chinese hamster ovary cells: absence of strand specificity in the dihydrofolate reductase gene.

Scicchitano, D A; Hanawalt, P C

We have developed a quantitative method for examining the removal of N-methylpurines from specific genes to investigate their possible differential repair throughout the genome. Chinese hamster ovary cells were exposed to dimethyl sulfate, and the isolated DNA was treated with an appropriate restric...

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Relationship of repair and replicative DNA synthesis to cell cycle in Chinese hamster Ovary (CHO-K1) cells

Chou, Wu Ming; Mikhailova, Marina; Poirier, Lionel A.; Bánfalvi Gáspár (1943-) (biológus)

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Postreplication repair and the susceptibility of Chinese hamster cells to cytotoxic and mutagenic effects of alkylating agents.

Friedman, J; Huberman, E

A cell variant (VR-43) resistant to the cytotoxic effect of N-methyl-N'-nitro-N-nitrosoguanidine and N-methyl-N'-nitro-N-nitrosourea was isolated from Chinese hamster V79 cells for use in studies of the relationship among cell survival, mutagenesis, and DNA repair by alkylating agents. Resistance to...

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Persistent DNA damage inhibits S-phase and G2 progression, and results in apoptosis.

Orren, D K; Bohr, V A; Petersen, L N

We used genetically related Chinese hamster ovary cell lines proficient or deficient in DNA repair to determine the direct role of UV-induced DNA photoproducts in inhibition of DNA replication and in induction of G2 arrest and apoptosis. UV irradiation of S-phase-synchronized cells causes delays in ...

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Nucleotide Excision repair pathway modulating both cancer risk and therapy

Abbasi, Rashda

Nukleotid Exzisions Reparatur (NER) spielt eine wichtige Rolle bei der Reparatur vieler verschiedener Arten von DNA-Schäden, dazu gehören auch DNA-Addukte, die durch ultraviolette Strahlung und durch Exposition gegenüber schädlichen Substanzen wie Tabakrauch und Alkohol entstehen. Genetische Variati...

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Mutations in hamster single-strand break repair gene XRCC1 causing defective DNA repair.

Thompson, L H; Shen, M R; Mohrenweiser, H; Zdzienicka, M Z; Thelen, M P

The molecular basis for the DNA repair dysfunction observed in mutant Chinese hamster ovary cell lines of X-ray repair cross complementing group 1 (XRCC1) is unknown and the exact role of the XRCC1 protein remains unclear. To help clarify the role of the XRCC1 gene we analyzed four mutant cell lines...

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Mutation of a BRCT domain selectively disrupts DNA single-strand break repair in noncycling Chinese hamster ovary cells

Caldecott, Keith W.; Moore, David J.; Clements, Paula; Taylor, Richard M.

The DNA single-strand break repair protein XRCC1 contains a BRCT domain that binds and stabilizes intracellular DNA ligase III protein. We recently demonstrated that this domain is largely dispensable for single-strand break repair and cellular resistance to DNA base damage in cycling cells. Here, w...

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Multiple subphases of DNA repair and poly (ADP-ribose) synthesis in Chinese hamster ovary (CHO-K1) cells

Szepessy Edit; Bánfalvi Gáspár (1943-) (biológus); Jenei Zsolt; Serfőző Zoltán; Csuka Ildikó; James, Jill

The two types of DNA synthesis as well as poly(ADP-ribose) biosynthesis were measured simultaneously in synchronized intact populations of CHO cells throughout the duration of S phase. Naturally occurring DNA fragmentation was detected by random primed oligonucleotide synthesis (ROPS assay). Fractio...

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

Troelstra, C.; Odijk, H.; Wit, J. de; Westerveld, A.; Thompson, L.H.; Bootsma, D.; Hoeijmakers, J.H.J.

The UV-sensitive, nucleotide excision repair-deficient Chinese hamster mutant cell line UV61 was used to identify and clone a correcting human gene, ERCC-6. UV61, belonging to rodent complementation group 6, is only moderately UV sensitive in comparison with mutant lines in groups 1 to 5. It harbors...

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

Westerveld, A; Troelstra, C; de Wit, J; Odijk, H; Thompson, L H; Bootsma, D; Hoeijmakers, J H

The UV-sensitive, nucleotide excision repair-deficient Chinese hamster mutant cell line UV61 was used to identify and clone a correcting human gene, ERCC-6. UV61, belonging to rodent complementation group 6, is only moderately UV sensitive in comparison with mutant lines in groups 1 to 5. It harbors...

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Molecular cloning and biological characterization of a human gene, ERCC2, that corrects the nucleotide excision repair defect in CHO UV5 cells.

Thompson, L H; Weber, C A; Stewart, S A; Salazar, E P

The UV-sensitive Chinese hamster ovary (CHO) cell line UV5, which is defective in the incision step of nucleotide excision repair, was used to identify and clone a complementing human gene, ERCC2, and to study the repair process. Genomic DNA from a human-hamster hybrid cell line was sheared and cotr...

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Mismatch Repair by Efficient Nick-Directed, and Less Efficient Mismatch-Specific, Mechanisms in Homologous Recombination Intermediates in Chinese Hamster Ovary Cells

Nickoloff, J. A.; Miller, E. M.; Cho, J. W.; Hough, H. L.

Repair of single-base mismatches formed in recombination intermediates in vivo was investigated in Chinese hamster ovary cells. Extrachromosomal recombination was stimulated by double-strand breaks (DSBs) introduced into regions of shared homology in pairs of plasmid substrates heteroallelic at 11 p...

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Microsatellite instability and novel mismatch repair gene mutations in northern Chinese population with Hereditary non-polyposis colorectal cancer

Sheng, JQ; Chan, TL; Chan, YW; Huang, JS; Chen, JG; Zhang, MZ; Guo, XL; Mu, H; Chan, ASY; Li, SR; Yuen, ST; Leung, SY

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Localization of the xeroderma pigmentosum group B-correcting gene ERCC-3 to human chromosome 2q21.

Weeda, G.; Wiegant, J.; Ploeg, M. van der; Geurts van Kessel, A.H.M.; Eb, A.J. van der; Hoeijmakers, J.H.J.

The human excision-repair gene ERCC3 was cloned after DNA-mediated gene transfer to the uv-sensitive Chinese hamster ovary mutant cell line 27-1, a member of complementation group 3 of the excision-defective rodent cell lines. The ERCC3 gene specifically corrects the DNA repair defect of xeroderma p...

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

Troelstra, C.; Landsvater, R.M.; Wiegant, J.; Ploeg, M. van der; Viel, G.; Buys, C.H.C.M.; Hoeijmakers, J.H.J.

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

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Language awareness in language education

Berry, Roger; Berry, Vivien; Nunan, David

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Isolation and partial characterisation of a Chinese hamster O6-alkylguanine-DNA alkyltransferase cDNA.

Cawkwell, L; Rafferty, J A; Watson, A J; Elder, R H; Potter, P M; Margison, G P

The cDNA encoding Chinese hamster O6-alkylguanine-DNA-alkyltransferase (ATase) has been isolated from a library prepared from RNA isolated from V79 lung fibroblasts which had an upregulated level of this repair activity following stepwise selection with a chloroethylating agent (1, 2). Expression of...

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Induction of beta-polymerase mRNA by DNA-damaging agents in Chinese hamster ovary cells.

Wilson, S H; Fornace, A J; Hollander, M C; Zmudzka, B

Only a few of the genes involved in DNA repair in mammalian cells have been isolated, and induction of a DNA repair gene in response to DNA damage has not yet been established. DNA polymerase beta (beta-polymerase) appears to have a synthetic role in DNA repair after certain types of DNA damage. Her...

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Human repair gene restores normal pattern of preferential DNA repair in repair defective CHO cells.

Hanawalt, P C; Bohr, V A; van Duin, M; Chu, E H; Okumoto, D S

The pattern of preferential DNA repair of UV-induced pyrimidine dimers was studied in repair-deficient Chinese hamster ovary (CHO) cells transfected with the human excision repair gene, ERCC-1. Repair efficiency was measured in the active dihydrofolate reductase (DHFR) gene and in its flanking, non-...

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Human chromosome 5 complements the DNA double-strand break-repair deficiency and gamma-ray sensitivity of the XR-1 hamster variant.

Mirman, D; Giaccia, A J; MacLaren, R; Denko, N; Waldren, C; Hart, I; Stamato, T D

XR-1 is a Chinese hamster ovary (CHO) cell mutant which is unusually sensitive to killing by gamma rays in the G1 portion of the cell cycle but has nearly normal resistance to gamma-ray damage in late S phase. The cell-cycle sensitivity correlates with the mutant's inability to repair DNA double-str...

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Genetic diversity of UV-sensitive DNA repair mutants of Chinese hamster ovary cells.

Mooney, C L; Thompson, L H; Brookman, K; Busch, D B; Glaser, D A

Mutant lines of Chinese hamster ovary cells that show hypersensitivity to killing and mutagenesis by UV light were analyzed by genetic complementation analysis to determine whether defects in different gene loci might underlie a common cellular phenotype,. To facilitate rapid screening of mutant clo...

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Genetic complementation of UV-induced DNA repair in Chinese hamster ovary cells by the denV gene of phage T4.

Valerie, K; Henderson, E E; de Riel, J K

The denV gene of phage T4, encoding the pyrimidine dimer-specific DNA repair enzyme endonuclease V, has been introduced by DNA transfection into the UV-sensitive DNA repair-deficient Chinese hamster ovary (CHO) cell line UV5. Transformants were first selected for resistance to the antibiotic G418 co...

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Gene-specific and strand-specific DNA repair in the G1 and G2 phases of the cell cycle.

Petersen, L N; Bohr, V A; Orren, D K

We have analyzed the fine structure of DNA repair in Chinese hamster ovary (CHO) cells within the G1 and G2 phases of the cell cycle. Repair of inactive regions of the genome has been suggested to increase in the G2 phase of the cell cycle compared with other phases. However, detailed studies of DNA...

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Gene recombination in X-ray-sensitive hamster cells.

Hamilton, A A; Thacker, J

Recombination was measured in Chinese hamster ovary (CHO-K1) cells and in the X-ray-sensitive mutants xrs1 and xrs7, which show a defect in DNA double-strand break repair. To assay recombination, pairs of derivatives of the plasmid pSV2gpt were constructed with nonoverlapping deletions in the gpt ge...

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Functional nucleotide excision repair is required for the preferential removal of N-ethylpurines from the transcribed strand of the dihydrofolate reductase gene of Chinese hamster ovary cells.

Scicchitano, D A; Sitaram, A; Wang, W; Plitas, G

Transcription-coupled repair of DNA adducts is an essential factor that must be considered when one is elucidating biological endpoints resulting from exposure to genotoxic agents. Alkylating agents comprise one group of chemical compounds which modify DNA by reacting with oxygen and nitrogen atoms ...

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Frequent microsatellite instability and mismatch repair gene mutations in young Chinese patients with colorectal cancer

Chan, TL; Yuen, ST; Chung, LP; Ho, JWC; Kwan, KYM; Chan, ASY; Ho, JCY; Leung, SY; Wyllie, AH

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Enhancement of postreplication repair in ultraviolet-light-irradiated Chinese hamster cells by irradiation in G2 or S-phase.

D'Ambrosio, S M; Setlow, R B; Aebersold, P M

Postreplication repair in synchronous Chinese hamster cells was determined after split doses of ultraviolet (UV) radiation. Repair was enhanced by irradiation of cells in G2 or S-phase with a small dose of UV radiation at least 1.5 h before a three-fold larger dose of UV. There was significantly gre...

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Enhancement of postreplication repair in Chinese hamster cells.

D'Ambrosio, S M; Setlow, R B

Alkaline sedimentation profiles of pulse-labeled DNA from Chinese hamster cells showed that DNA from cells treated with N-acetoxy-acetylaminofluorene or ultraviolet radiation was made in segments smaller than those from untreated cells. Cells treated with a small dose (2.5 muM) of N-acetoxy-acetylam...

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Enhanced fidelity for rejoining radiation-induced DNA double-strand breaks in the G2 phase of Chinese hamster ovary cells

Krüger, Ines; Löbrich, Markus; Rothkamm, Kai

The influence of cell cycle phase on the fidelity of DNA double-strand break (DSB) repair is largely unknown. We investigated the rejoining of correct and incorrect DSB ends in synchronized populations of Chinese hamster ovary cells irradiated with 80 Gy X-rays. A specialized pulsed-field gel electr...

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End extension repair of introduced targeting vectors mediated by homologous recombination in mammalian cells.

Aratani, Y; Koyama, H; Okazaki, R

We have studied the mechanism of targeted recombination in mammalian cells using a hemizygous adenine phosphoribosyltransferase-deficient (APRT-) Chinese hamster ovary (CHO) cell mutant as a recipient. Three structurally different targeting vectors with a 5' or a 3', or both, end-deleted aprt sequen...

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Efficient repair of all types of single-base mismatches in recombination intermediates in Chinese hamster ovary cells. Competition between long-patch and G-T glycosylase-mediated repair of G-T mismatches.

Nickoloff, J A; Bill, C A; Miselis, N R; Duran, W A

Repair of all 12 single-base mismatches in recombination intermediates was investigated in Chinese hamster ovary cells. Extrachromosomal recombination was stimulated by double-strand breaks in regions of shared homology. Recombination was predicted to occur via single-strand annealing, yielding hete...

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Effects of genomic context and chromatin structure on transcription-coupled and global genomic repair in mammalian cells

Tang, Moon-shong; Feng, Zhaohui; Chasin, Lawrence A.; Hu, Wenwei

It has been long recognized that in mammalian cells, DNA damage is preferentially repaired in the transcribed strand of transcriptionally active genes. However, recently, we found that in Chinese hamster ovary (CHO) cells, UV-induced cyclobutane pyrimidine dimers (CPDs) are preferentially repaired i...

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Effect of cadmium on the relationship between replicative and repair DNA synthesis in synchronized CHO cells

Littlefield, Niel; Bánfalvi Gáspár (1943-) (biológus); Hass, Bruce; Mikhailova, Marina; Csuka Ildikó; Szepessy Edit

Repair and replicative DNA synthesis were measured at different stages of the cell cycle in control and cadmium-treated Chinese hamster ovary (CHO-K1) cells. Cells were synchronized by counterflow centrifugal elutriation. Elutriation resulted in five repair and four replication subphases. On Cd trea...

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ERCC2: cDNA cloning and molecular characterization of a human nucleotide excision repair gene with high homology to yeast RAD3.

Thompson, L H; Weber, C A; Stewart, S A; Salazar, E P

Human ERCC2 genomic clones give efficient, stable correction of the nucleotide excision repair defect in UV5 Chinese hamster ovary cells. One clone having a breakpoint just 5' of classical promoter elements corrects only transiently, implicating further flanking sequences in stable gene expression. ...

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Demethylation enhances removal of pyrimidine dimers from the overall genome and from specific DNA sequences in Chinese hamster ovary cells.

Ho, L; Hanawalt, P C; Bohr, V A

We have examined the effects of changes in cytosine methylation on DNA repair in UV-irradiated Chinese hamster ovary (CHO) cells. A hypomethylated derivative of the CHO K1B11 line, B11aza, was established by passaging B11 cells over several months in increasing concentrations of 5-azacytidine; great...

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Damage and Repair of DNA in 5-Bromodeoxyuridine-Labeled Chinese Hamster Cells Exposed to Fluorescent Light

Ben-Hur, E.; Elkind, M. M.

Illumination of Chinese hamster cells with fluorescent light after 5-bromodeoxyuridine incorporation leads to extensive single-strand breakage in the DNA of the exposed cells. The rate of production of single-strand breaks is dependent on the extent to which thymine is replaced by 5-bromouracil. At ...

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DNA-mediated transfer of a human DNA repair gene that controls sister chromatid exchange.

Fuscoe, J C; Thompson, L H; Minkler, J L; Brookman, K W; Henning, K A; Carrano, A V

The Chinese hamster cell line mutant EM9, which has a reduced ability to repair DNA strand breaks, is noted for its highly elevated frequency of sister chromatid exchange, a property shared with cells from individuals with Bloom's syndrome. The defect in EM9 cells was corrected by fusion hybridizati...

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DNA-mediated cotransfer of excision repair capacity and drug resistance into chinese hamster ovary mutant cell line UV-135.

Strniste, G F; MacInnes, M A; Thompson, L H; Bingham, J M

We have investigated DNA-mediated transfer of aminopterin resistance conferred by plasmid and UV resistance conferred by genomic DNA to the Chinese hamster ovary (CHO) cell line UV-135, a UV-sensitive mutant defective in nucleotide excision repair. Plasmid pSV2gpt-CaPO4 coprecipitates induced aminop...

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DNA strand-specific repair of (+-)-3 alpha,4 beta-dihydroxy-1 alpha,2 alpha-epoxy-1,2,3,4-tetrahydrobenzo[c]phenanthrene adducts in the hamster dihydrofolate reductase gene.

Zhang, Y J; Carothers, A M; Mucha, J; Zhen, W; Santella, R M; Grunberger, D; Bohr, V A

We evaluated the formation and removal of (+-)-3 alpha,4 beta-dihydroxy-1 alpha,2 alpha-epoxy-1,2,3,4- tetrahydrobenzo[c]phenanthrene (BcPHDE)-DNA adducts in two Chinese hamster ovary (CHO) cell lines. One line of repair-proficient cells (MK42) carries a stable 150-fold amplification of the dihydrof...

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DNA strand specificity for UV-induced mutations in mammalian cells.

Zdzienicka, M Z; Vrieling, H; Groen, N A; Van Rooijen, M L; Simons, J W; Lohman, P H; van Zeeland, A A

The influence of DNA repair on the molecular nature of mutations induced by UV light (254 nm) was investigated in UV-induced hprt mutants from UV-sensitive Chinese hamster cells (V-H1) and the parental line (V79). The nature of point mutations in hprt exon sequences was determined for 19 hprt mutant...

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DNA strand breaks, repair, and survival in x-irradiated mammalian cells.

Dugle, D L; Chapman, J D; Gillespie, C J

The yields of unrepairable single-and double-strand breaks in the DNA of x-irradiated Chinese hamster cells were measured by low-speed neutral and alkaline sucrose density gradient sedimentation in order to investigate the relation between these lesions and reproductive death. After maximal single-s...

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DNA repair in the metallothionein gene increases with transcriptional activation.

Okumoto, D S; Bohr, V A

We have studied DNA repair in the Chinese Hamster Ovary (CHO) metallothionein (MT) gene after UV-light induced damage. The repair was examined comparatively with or without transcriptional activation of the gene by incubation in the presence of the heavy metal ZnCl2. Whereas the repair efficiency wa...

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Complementation of sensitivity to alkylating agents in Escherichia coli and Chinese hamster ovary cells by expression of a cloned bacterial DNA repair gene.

Kataoka, H; Karran, P; Hall, J

Dual expression vectors derived from pSV2gpt and encoding all or part of the Escherichia coli ada+ gene have been constructed. Following transformation into an E. coli ada strain or transfection and stable integration into the genome of Chinese hamster ovary (CHO) cells, plasmid vectors containing t...

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Chromosomal Aberrations and Mortality of X-Irradiated Mammalian Cells: Emphasis on Repair

Dewey, W. C.; Leeper, D. B.; Miller, H. H.

Chromosomal aberrations induced by x-rays in synchronized Chinese hamster cells correlated well with mortality as the radiosensitivity was made to vary by a factor of 4 by treating the cells with colcemid or 5-bromodeoxyuridine and by irradiating the cells in different parts of the cell cycle. 37% s...

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Changes in repair competency after 5-bromodeoxyuridine pulse labeling and near-ultraviolet light.

Hagan, M P; Elkind, M M

Synchronized V79 Chinese hamster cells, pulse-labeled with 5-bromodeoxyuridine (BrdUrd), show marked changes in the sensitivity to near-ultraviolet light during the cell cycle. Cells are least sensitive during the remainder of the S-phase after the BrdUrd pulse. They become maximally sensitive in th...

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Cell Proliferation and DNA Breaks Are Involved in Ultraviolet Light-induced Apoptosis in Nucleotide Excision Repair-deficient Chinese Hamster Cells

Dunkern, Torsten R.; Kaina, Bernd

UV light targets both membrane receptors and nuclear DNA, thus evoking signals triggering apoptosis. Although receptor-mediated apoptosis has been extensively investigated, the role of DNA damage in apoptosis is less clear. To analyze the importance of DNA damage induced by UV-C light in apoptosis, ...

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Both replication bypass fidelity and repair efficiency influence the yield of mutations per target dose in intact mammalian cells induced by benzo[a]pyrene-diol-epoxide and dibenzo[a,l]pyrene-diol-epoxide.

Lagerqvist, Anne; Hakansson, Daniel; Prochazka, Gabriela; Lundin, Cecilia; Dreij, Kristian; Segerback, Dan; Jernstrom, Bengt

Mutations induced by polycyclic aromatic hydrocarbons (PAH) are expected to be produced when error-prone DNA replication occurs across unrepaired DNA lesions formed by reactive PAH metabolites such as diol epoxides. The mutagenicity of the two PAH-diol epoxides (+)-anti-7,8-dihydroxy-9,10-epoxy-7,8,...

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Biased short tract repair of palindromic loop mismatches in mammalian cells.

Taghian, D G; Nickoloff, J A; Hough, H

Mismatch repair of palindromic loops in the presence or absence of single-base mismatches was investigated in wild-type and mismatch-binding defective mutant Chinese hamster ovary cells. Recombination intermediates with a maximum heteroduplex DNA (hDNA) region of 697 bp contained a centrally located...

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Azacytidine-induced reactivation of a DNA repair gene in Chinese hamster ovary cells.

Jeggo, P A; Holliday, R

Six X-ray-sensitive (xrs) strains of the CHO-K1 cell line were shown to revert at a very high frequency after treatment with 5-azacytidine. This suggested that there was a methylated xrs+ gene in these strains which was structurally intact, but not expressed. The xrs strains did not complement one a...

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Assessment of the significance of mitochondrial DNA damage by chemotherapeutic agents

Lo, S; Tolner, B; Taanman, JW; Cooper, JM; Gu, M; Hartley, JA; Schapira, AHV; Hochhauser, D

The pathways which are activated following damage to nuclear DNA in cancer cells are well understood. There is evidence that treatment with several chemotherapeutic agents may result in damage to mitochondrial DNA. This study investigated the contribution of mitochondrial DNA to cytotoxicity of DNA-...

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An interaction between the mammalian DNA repair protein XRCC1 and DNA ligase III.

Ljungquist, S; Caldecott, K W; Tucker, J D; McKeown, C K; Thompson, L H

XRCC1, the human gene that fully corrects the Chinese hamster ovary DNA repair mutant EM9, encodes a protein involved in the rejoining of DNA single-strand breaks that arise following treatment with alkylating agents or ionizing radiation. In this study, a cDNA minigene encoding oligohistidine-tagge...

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A yeast DNA repair gene partially complements defective excision repair in mammalian cells.

Schultz, R A; Lambert, C; Weiss, W A; Couto, L B; Thompson, L H; Friedberg, E C

The RAD10 gene of Saccharomyces cerevisiae is required for nucleotide excision repair of DNA. Expression of RAD10 mRNA and Rad10 protein was demonstrated in Chinese hamster ovary (CHO) cells containing amplified copies of the gene, and RAD10 mRNA was also detected in stable transfectants without gen...

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A linear-quadratic model of cell survival considering both sublethal and potentially lethal radiation damage Un modèle linéaire-quadratique de la survie cellulaire considérant à la fois sublétale et potentiellement mortelle d'irradiation dégâts

Coucke, Philippe; Rutz; Mirimanoff

We assessed the dose-dependence of repair of potentially lethal damage in Chinese hamster ovary cells x-irradiated in vitro. The recovery ratio (RR) by which survival (SF) of the irradiated cells was enhanced increased exponentially with a linear and a quadratic component, namely xi and psi: RR = e ...

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A Role for DNA Mismatch Repair Protein Msh2 in Error-Prone Double-Strand-Break Repair in Mammalian Chromosomes

Smith, Jason A.; Waldman, Alan S.; Waldman, Barbara Criscuolo

We examined error-prone nonhomologous end joining (NHEJ) in Msh2-deficient and wild-type Chinese hamster ovary cell lines. A DNA substrate containing a thymidine kinase (tk) gene fused to a neomycin-resistance (neo) gene was stably integrated into cells. The fusion gene was rendered nonfunctional du...

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Zhang, Wei; 張惟

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Feuchtwang, Stephan

The essays in this volume present contemporary anthropological perspectives on Chinese kinship, its historical complexity and its modern metamorphoses. The collection draws particular attention to the reverberations of larger socio-cultural and politico-economic processes in the formation of sociali...

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5-bromodeoxyuridine-DNA strand symmetry and the repair of photolytic breaks in Chinese hamster cell chromosomes.

Roufa, D J

Experiments described in this report quantiate the black light sensitivities of Chinese hamster lung (CHL) cells containing BrdUrd-DNA of defined composition. Cesium chloride equilibrium gradient centrifugation provides estimates both of the percent thymidine replacement by BrdUrd and of the symmetr...

DRIVER (Chinese)