• Journal of Radiation Industry
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• v.2 no.3
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• pp.111-119
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• 2008

Microarrays can measure the expression of thousands of genes to identify the changes in expression between different biological states. To survey the change of whole Salmonella genes after a relatively high dose of gamma radiation (1 kGy), transcriptome dynamics were examined in the cells by using DNA microarrays. At least 75 genes were induced and 89 genes were reduced two-fold or more after irradiation. Several genes located in pSLT plasmid, cyo operon, and Gifsy prophage were induced along with many genes encoding uncharacterized proteins.While, the expression of genes involved in the virulence of Salmonella as well as metabolic functions were decreased. Although the radiation response as a whole could not be illustrated by using DNA microarrays, the data suggest that the response to high dose of irradiation might be more complex than the SOS response.

• Radiation Oncology Journal
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• v.23 no.1
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• pp.43-50
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• 2005

Purpose : A number of genes and their products are Induced early or late following exposure of cells to ionizing radiation. These radiation-Induced genes have various effects on irradiated cells and tissues. Suppression subtractive hybridization (SSH) based on PCR was used to Identify the differentially expressed genes by radiation in cervix carcinoma cells. Materials and Methods : Total RNA and poly $(A)^+$ mRNA were Isolated from Irradiated and non-irradiated HeLa cells. Forward- and reverse-subtracted cDNA libraries were constructed using SSH. Eighty-eight clones of each were used to randomly select differentially expressed genes using reverse Northern blotting (dot blot analysis). Northern blotting was used to verify the screened genes. Results : Of the 17t clones, 10 genes in the forward-subtracted library and 9 genes In the reverse-subtracted library were identified as differentially expressed radiation-induced genes by PCR-select differential screening. Three clones from the forward-subtracted library were confirmed by Northern blotting, and showed increased expression in a dose-dependent manner, including a telomerase catalytic subunit and sodium channel-like protein gene, and an ESTs (expressed sequence tags) gene. Conclusion : We Identified differentially expressed radiation-induced genes with low-abundance genes with SSH, but further characterization of theses genes are necessary to clarify the biological functions of them.

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.472-477
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• 2004

To study the radiation related gene expression in mutants of Bacillus lentimorbus WJ5 induced by gamm radiation, the simultaneous gene expression was analyzed by DNA micro array. We constructed DNA chips including two thousand randomly digested genome spots of B. lentimorbus WJ5 and compared its quantitative aspect with seven mutants induced by gamma radiation $(^{60}/Co)$. From the cluster analysis of gene expression pattern, totally 408 genes were expressed and 27 genes were significantly upregulated by the gamma radiation in all mutants. Especially, genes involved in repair (mutL, mutM), energy metabolism (acsA, sdhB, pgk, yhjB, citB), protease (npr), and reduction response to oxidative stress (HMM) were simultaneously upregulated. It seems that the induction of the direct and/or indirect repair related genes in mutants induced by gamma radiation could be remarkably different from the adaptive responses against acute exposure to radiation.

• Korean Journal of Environmental Biology
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• v.20 no.4
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• pp.316-324
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• 2002

To investigate the mutational spectrum of laccase (Lac) genes (lac -A and lac -B) involved in degrading lignin which is the recalcitrant cell wall polymer, the genes of the Pleurotus ostreatus mutants induced by gamma ray radiation were amplified by PCR and were cloned. All partial lac-A genes of 4 mutants (PO-6, -7, -14 and -15) consisted of 1763 base pairs due to the deletion of two bases (491-nt and 492-nt) and addition of one base (875-nt) in 1764 base pairs of lac -A gene of PO-1. Totally 36 mutational hot spots were detected and 32 positions were mutated in all of those 4 mutants simultaneously. These mutations were predominantly A : T -> G : C transitions (40%). Putative amino acid sequences of lac -A genes of mutants have one simultaneous mutated residue (from Thr-44 to Ala-44). The 1764 bp of partial lac -B gene was cloned only in PO -5 mutant and contained 19 mutated bases. These mutations were predominantly G : C->A : T transitions (45%). Lac-B protein of PO-5 has two mutated residues of Glu-290 and His-363 from Ala-290 and Phe-363, respectively. The hyper-mutational positions were concentrated in specific regions of between 50-nt and 900-nt in lac genes. These results suggested that the mutational hotspots responded to gamma radiation could be in some genes, at least lac -A and lac -B of p. ostreatus.

• The Korean Journal of Nuclear Medicine
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• v.34 no.2
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• pp.144-153
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• 2000

Purpose: The purpose of this study was to evaluate the relationship between radiation-induced activation of DNA repair genes and radiation induced apoptosis in A431 cell line. Materials and Methods: 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. Results: 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. Conclusion: 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.

• Environmental Mutagens and Carcinogens
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• v.22 no.3
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• pp.142-148
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• 2002

Although ionizing radiation (IR) has been used to treat the various human cancers, IR is cytotoxic not only to cancer cells but to the adjacent normal tissue. Since normal tissue complications are the limiting factor of cancer radiotherapy, one of the major concerns of IR therapy is to maximize the cancer cell killing and to minimize the toxic side effects on the adjacent normal tissue. As an attempt to develop a method to monitor the degree of radiation exposure to normal tissues during radiotherapy, we investigated the transcriptional responses of human peripheral blood lymphocytes (PBL) following IR using cDNA microarray chip containing 1,221 (1.2 K) known genes. Since conventional radiotherapy is delivered at about 24 h intervals at 180 to 300 cGy/day, we analyzed the transcriptional responses ex-vivo irradiated human PBL at 200 cGy for 24 h-period. We observed and report on 1) a group of genes transiently induced early after IR at 2 h, 2) of genes induced after IR at 6 h, 3) of genes induced after IR at 24 h and on 4) a group of genes whose expression patters were not changed after IR. Since Biological consequences of IR involve generation of various reactive oxygen species (ROS) and thus oxidative stress induced by the ROS is known to damage normal tissues during radiotherapy, we further tested the temporal expression profiles of genes involved in ROS modulation by RT-PCR. Specific changes of 6 antioxidant genes were identified in irradiated PBL among 9 genes tested. Our results suggest the potential of monitoring post-radiotherapy changes in temporal expression profiles of a specific set of genes as a measure of radiation effects on normal tissues. This type of approach should yield more useful information when validated in in vivo irradiated PBL from the cancer patients.

• Journal of Radiation Industry
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• v.4 no.4
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• pp.325-334
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• 2010

Transcriptional regulation in response to salt in mutant lines was investigated using oligonucleotide microarrays. In order to characterize the salt-responsive genes in rice, the expression profiles of transcripts that responded to salt-treatment were monitored using the microarrays. In the microarray analysis, among 37,299 reliable genes, 5,101, 2,758 and 2,277 genes were up-regulated by more than 2-fold using the salt treatment, while the numbers of down-regulated genes were 4,619, 3,234, and 1,878 in the WT, ST-495, and ST-532, respectively. From genotype changes induced by gamma ray mutagenesis, 3,345 and 2,397 genes were up-regulated, while 2,745 and 2,075 genes were down-regulated more than 2-fold in the two untreated mutants lines compared with untreated WT, respectively. A total of 3,108 and 2,731 genes were up-regulated more than 2-fold, while 3,987 and 3,660 genes were down-regulated by more than 2-fold in the salt treatment of the two mutants lines compared with the salt treated WT, respectively. The expressions of membrane transporter genes such as OsAKT1, OsKUP, and OsNAC increased more severely in ST-495 and ST-532 than in the WT. The expressions of the proline accumulation related genes such as OsP5CS and OsP5CR were also markedly increased in the salt tolerant mutants when compared to the WT plant.

• Journal of Applied Biological Chemistry
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• v.48 no.1
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• pp.1-6
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• 2005

Analysis of chlorophyll (Chl) fluorescence implicated treatment of 40 mM NaCl decreased maximal photochemical efficiency of photosystem II (PSII) (Fv/Fm), actual quantum yield of PSII (${\Phi}_{PSII}$), and photochemical quenching (qP) in rice, but increased non-photochemical quenching (NPQ). Decreases in Fv/Fm, ${\Phi}_{PSII}$, and qP were significantly alleviated by $30\;{\mu}M$ jasmonic acid (JA), while NPQ increase was enhanced. Transcription levels of antioxidant isoenzyme genes were differentially modulated by NaCl treatment. Expression of cCuZn-SOD2 gene increased, while those of cAPXb, CATb, and CATc genes decreased. JA prevented salt-induced decrease of pCuZn-SOD gene expression, but caused greater decrease in mRNA levels of cAPXa and Chl_tAPX genes. Investigation of vacuolar $Na^+/H^+$ exchanger (NHX2) and 1-pyrroline-5-carboxylate synthetase (P5CS) gene expressions revealed transcription level of NHX2 gene was increased by JA, regardless of NaCl presence, while that of P5CS gene slightly increased only in co-presence of JA and NaCl. Unlike JA, ${\gamma}$-radiation rarely affected expressions of antioxidant isoenzyme, NHX2, and P5CS genes, except for increase in mRNA level of Chl_tAPX and decrease in that of pCuZn-SOD. These results demonstrate enhanced salt-tolerance in JA-treated rice seedlings may be partly due to high transcription levels of pCuZn-SOD, NHX2, and P5CS genes under salt stress.

• Korean Journal of Environmental Biology
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• v.23 no.1
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• pp.21-26
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• 2005

Cell response to genotoxic agents is complex and involves the participation of different classes of genes including cell cycle control, DNA repair and apoptosis. In this report, we presented a approach to characterize the cellular functions associated with the altered transcript profiles of MCF-7 exposed to low-dose in vitro gamma-irradiation. We used the method of human 2.4 k cDNA microarrays containing apoptosis, cell cycle, chromatin, repair, stress and chromosome genes to analyze the differential gene expression characterization that were displayed by radiation-exposed cell, human breast carcinoma MCF-7 cell line, such as 4 Gy 4 hr, 8 Gy 4 hr, and 8 Gy 12 hr. Among these genes, 66 were up-regulated and 49 were down-regulated. Specific genes were concomitantly induced in the results. Cyclin dependent kinase 4 (Cdk4) is induced for starting the cell cycle. This regulation is required for a DNA damage­induced G1 arrest. In addition to, an apoptotic pathways gene Bcl-w was concomitantly induced. Mismatch repair protein homologue-l (hMLH1), a necessary component of DNA mismatch protein repair (MMR), in G2-M cell cycle checkpoint arrest. The present study provides new information on the molecular mechanism underlying the cell response to genotoxic stress, with relevance to basic and clinical research.

• BMB Reports
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• v.36 no.1
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• pp.144-148
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• 2003

During the past 2 decades, radiation tumorigenesis researchers have focused on cellular and molecular mechanisms. We reviewed some of these research fields, since they may specifically relate to the induction of cancer by ionizing radiation. First, radiation-mediated mutation was discussed. Then the initiating event in radiation carcinogenesis, as well as other genetic events that may by involved, is discussed in terms of the possible role of the activation of genes and the loss of cell-cycle checkpoints.