• Proceedings of the PSK Conference
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• 2003.04a
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• pp.206.1-206.1
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• 2003

The immunomodulator Ginsan has been found previously by us to stimulate the secretion of high levels of IL -1. IL -6 and TNF-alpha in irradiated mice. These cytokines are known to induce proliferation and differentiation of hematopoietic progenitor cells from the spleen and bone marrow and to protect mice from DNA-damaging agents. The present studies were evaluated as a cytoprotective agent against toxicity of the alkylating drugs. (omitted)

• Journal of Life Science
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• v.16 no.4
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• pp.704-709
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• 2006

The present study intends to characterize the DNA damage-inducible responses in Caenorhabditis elegans. To study UV-inducible responses in C. elegans, two UV-inducible cDNA clones were isolated from C. elegans by using subtration hybridization method. To investigate the expression of isolated genes, UV100 and UV150, the cellular levels of the transcript were determined by Northern blot analysis after UV-irradiation. The transcripts of isolated gene increased rapidly and reached maximum accumulation after UV-irradiation. Compared to the message levels of control, the levels of maximal increase were approximately 2 folds to UV-irradiation. These results implied that the effects of damaging agents are complex and different regulatory pathways exist for the induction of these genes. To study the function of UV100 and UV150 gene in response to UV irradiation, we carried out a RNAi experiment and investigated the UV sensivity. This result indicated that UV100 gene involved in stage-specific repair pathway or regulated by development.

• Journal of Microbiology
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• v.41 no.1
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• pp.46-51
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• 2003

RAD6 in yeast mediates postreplication DNA repair and is responsible for DNA-damage induced mutations. RAD6 encodes ubiquitin-conjugating enzyme that is well conserved among eukaryotic organisms. However, the molecular targets and consequences of their ubiquitination by Rad6 have remained elusive. In Aspergillus nidulans, a RAD6 homolog has been isolated and shown to be an allele of uvs). We screened a CDNA library to isolate UVSJ-interacting proteins by the yeast two-hybrid system. JIPA was identified as an interactor of UVSJ. Their interaction was confirmed in vitro by a GST-pull down assay. JIPA was also able to interact with mutant UVSJ proteins, UVSJl and the active site cysteine mutant UVSJ-C88A. The N- and the C-terminal regions of UVSJ required for the interaction with UVSH, a RAD18 homolog of yeast which physically interacts with Rad6, were not necessary for the JIPA and UVSJ interactions. About 1.4 kb jipA transcript was detected in Northern analysis and its amount was not significantly increased in response to DNA-damaging agents. A genomic DNA clone of the jipA gene was isolated from a chromosome I specific genomic library by PCR-sib selection. Sequence determination of genomic and cDNA of jipA revealed an ORF of 893 bp interrupted by 2 introns, encoding a putative polypeptide of 262 amino acids. JIPA has 33% amino acid sequence identity to TIP41 of Saccharomyces cerevisiae which negatively regulates the TOR signaling pathway.

• Molecular & Cellular Toxicology
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• v.3 no.4
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• pp.231-237
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• 2007

Exposure to DNA-damaging agents can elicit a variety of stress-related responses that may alter the expression of genes associated with numerous biological pathways. We used 19 k whole human genome chip to detect gene expression profiles and potential signature genes in human normal hepatocytes (THLE-3) by treatment of five direct acting mutagens, furylfuramide (AF-2), N-nitroso-N-methylurea (MNU), methylmethanesulfonate (MMS), 4-nitroquinoline-N-oxide (4-NQO) and 2-nitrofluorene (2NF) of the $IC_{20}$ concentration for 3 h. Fifty one up-regulated common genes and 45 down-regulated common genes above 1.5-fold by five direct-acting mutagens were identified by clustering analysis. Many of these changed genes have some association with apoptosis, control of cell cycle, regulation of transcription and signal transduction. Genes related to these functions, as TP73L, E2F5, MST016, SOX5, MAFB, LIF, SII3, TFIIS, EMR1, CYTL1, CX3CR1 and RHOH are up-regulated. Down-regulated genes are ALOX15B, xs155, IFITM1, BATF, VAV2, CD79A, DCDC2, TNFSF8 and KOX8. We suggest that gene expression profiling on mutagens by toxicogenomic analysis affords promising opportunities to reveal potential new mechanistic markers of genotoxicity.

• Biomolecules & Therapeutics
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• v.15 no.4
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• pp.240-244
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• 2007

Cigarette smoking causes serious health problems in humans, especially if smoking habits are established during their adolescence. Nicotine is known to mutate DNA and interfere with apoptosis. Apoptosis is considered as a potent defense mechanism against cellular damaging agents. This study aims to investigate the effect of nicotine on the progression of apoptosis induced under ER stress conditions using four different established cell lines: HEK293, 3T3-L1, C2C12, and HepG2. When treated with nicotine, the progression of apoptosis was notably inhibited in the four cell lines according to the assays of caspase-3 activation and DNA fragmentation. In ER-stressed cells, nicotine appears to inhibit the progression of apoptosis in a concentration-dependent manner. When cells were treated with nicotine prior to ER stress, GRP94 level significantly increased compared to other ER stress markers of PDI and GRP78. This observation suggests that the inhibitory effect of nicotine may results from up-regulation of GRP94, an anti-apoptotic chaperone, under nicotine treatment. Taken together, the present study strongly implies that nicotine may inhibit apoptosis, caused by prolonged ER stress, based on promotion of GRP94 expression.

• Journal of Life Science
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• v.16 no.1
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• pp.126-130
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• 2006

The present study intends to characterize the DNA damage-inducible responses in yeast. The fission yeast, Schizosaccharomyces pombe was used in this study as a model system for higher eukaryotes. To study UV-inducible responses in S. pombe, five UV-inducible cDNA clones were isolated from S. pombe by using subtration hybridization method. To investigate the expression of isolated genes, UVI-155, the cellular levels of the transcripts were determined by Northern blot analysis after UV-irradiation. The transcripts of isolated gene (UVI-155) increased rapidly and reached maximum accumulation after UV-irradiation. Compared to the message levels of control, the levels of maximal increase were approximately 5 fold to UV-irradiation. In order to investigation whether the increase of UVI-l55 trascripts was a specific results of UV-irradiation, UVI-155 transcript levels were examined after treating the cells to mthylmethane sulfonate (MMS). The transcripts of UVI-155 were not induced by treatment of $0.25\%$ MMS. These results implied that the effects of damaging agents are complex and different regulatory pathways exist for the induction of these genes. To characterize the UVI-155 gene, gene deletion experiments were analyzed. The deleted strain was not well grown. This result indicated that the UVI-155 gene is essential for cell viability.

• Journal of Life Science
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• v.14 no.6 s.67
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• pp.1023-1027
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• 2004

The RAD3 gene of Saccharomyces cerevisiae is essential for the incision step of UV-induced excision repair. An yeast RAD3 gene has been previously isolated by functional complementation. In order to identify the RAD3 homologous gene from fungus Coprinus cinereus, we have constructed cosmid libraries from electrophoretically separated chromosomes of the C. cinereus. The 13 C. cinereus chromosomes were resolved by pulse-field gel electrophoresis, hybridized with S. cerevisiae RAD3 DNA, and then isolated RAD3 homologous DNA from C. cinereus chromosome. The RAD3 homolog DNA was contained in 3.2 kb DNA fragment. Here, we report the results of characterization of a fungus C. cinereus homolog to the yeast RAD3 gene. Southern blot analysis confirmed that the C. cinereus chromosome contains the RAD3 homolog gene and this gene exists as a single copy in C. cinereus genome. When total RNA isolated from the C. cinereus cells were hybridized with the 3.4 kb PvuII DNA fragment of the S. cerevisiae RAD3 gene, transcripts size of 2.8 kb were detected. In order to investigate whether the increase of the amount of transcripts by DNA damaging agent, transcript levels were examined after treating agents to the cells. The level of transcripts were not increased by untraviolet light (UV). This result indicated that the RAD3 homologous gene is not UV inducible gene. Gene deletion experiments indicate that the HRD3 gene is essential for viability of the cells and DNA repair function. These observations suggest an evolutionary conservation of other protein components with which HRD3 interacts in mediating its DNA repair and viability functions.

• Genomics & Informatics
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• v.15 no.4
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• pp.147-155
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• 2017

Apurinic/apyrimidinic endonuclease 1 (APE1) is an enzyme responsible for the initial step in the base excision repair pathway and is known to be a potential drug target for treating cancers, because its expression is associated with resistance to DNA-damaging anticancer agents. Although several inhibitors already have been identified, the identification of novel kinds of potential inhibitors of APE1 could provide a seed for the development of improved anticancer drugs. For this purpose, we first classified known inhibitors of APE1. According to the classification, we constructed two distinct pharmacophore models. We screened more than 3 million lead-like compounds using the pharmacophores. Hits that fulfilled the features of the pharmacophore models were identified. In addition to the pharmacophore screen, we carried out molecular docking to prioritize hits. Based on these processes, we ultimately identified 1,338 potential inhibitors of APE1 with predicted binding affinities to the enzyme.

• YAKHAK HOEJI
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• v.38 no.3
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• pp.332-337
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• 1994

Using germinal and somatic cell mutation assaying systems of Drosophila melanogaster, effects of Ginseng and Salvia miltiorrhiza extracts on the in vivo mutagenicity induced by N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) were investigated. For these purpose, the attached-X method and the mwh/flr spot test system which are an X-linked lethal mutation and a somatic chromosome mutation assaying system, respectively, were used. In the induction of X-linked lethal mutations during the spermatogenesis, MNNG showed more actions in the sperm and spermatid stages, in which Ginseng and Salvia miltiorrhiza extracts had remarkable inhibitory effects than other stages. Ginseng and Salvia miltiorrhiza extracts reduced the mutagenicity by MNNG in the mwh/flr system, which reveal that they can inhibit gene mutation, deletion and mitotic chromosomal recombination. These results seem to suggest that Ginseng and Salvia miltiorrhiza extracts may exert their inhibitory effects to in vivo mutagenic and/or carcinogenic properties of DNA-damaging agents.

• Journal of Environmental Science International
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• v.8 no.5
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• pp.569-574
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• 1999

This study was carried out to determine the antimutagenic effects of genistein on the somatic mutagenicity induced by aflatoxin B1 (${AFB}_1$), using Drosophila wing spot test system. Mutagen alone or mutagen with genistein were administered to the heterozygous(mwh/+) third instar larvae by feeding, and somatic cell mutations were detected in adult fly wing hairs. Genistein did not show any mutagenicity with the feeding concentrations of 5~15% in the test system. As the feeding concentrations of genistein increased, genistein inhibited the mutagenicity induced by AFB1 (14.6%~62.2% inhibition rate), while as the concentrations of AFB1 increased, small much spots that arise mostly from chromosome deletion and nondisjunction were more strongly suppressed by genistein than the large mwh spots from chromosomal recombination. In each group of different AFB1 concentrations, the rate of inhibition for total mwh spots was dependent on the dose of genistein. These results indicate that genistein have inhibitory effect on the mutagenicity induced by a mtagen, ${AFB}_1$. It seems to suggest that genistein may exert inhibitory effects to mutagenic and/or carcinogenic properties of DNA damaging agents.