• Biomolecules & Therapeutics
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• v.3 no.2
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• pp.122-131
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• 1995

Five human cancer cell lines (HeLa S3, Hep 3B, KATO III, Hs 683, HeLa MR) and one human normal cell line (WI-38) were examined cell viability, northern blot analysis, western blot analysis, and in situ hybridization for the expression $O_{6}$ -methylguanine-DNAmethyltransferase (MGMT), which can repair $O_{6}$ -methylguanine produced in DNA by alkylating agents. In cell viability test, the lethal sensitivities of each strain against anti-tumor drug N,N-bis(2-chloroethyl)- N-nitrosourea (BCNU) were counted, and both BCNU treated and untreated cell extracts were examined for their MGMT inducibility by RNA dot blot analysis. Cell lines did not show MGMT induction by BCNU pretreatment. Tlle MGMT activity was assayed by measuring the $^3$H radioactivity transferred from the substrate DNA containing [methyl-$^3$H)-O$_{6}$ -methylguanine to acceptor molecules in the cell extracts. Extracts from the majority of tumor strains and normal cells contained substantial MGMT activity of varying degree, while the known Mer$^{[-10]}$ cell (lacked or severely depleted in MGMT activity) Hela MR, and Hs 683 (proved to be Mer$^{[-10]}$ ) were much more sensitive to BCNU than the rest of tumor strains, as measured by cell viability test. Overall results above, KATO III showed the highest expression level of MGMT among the strains examined. Furthermore, with all the tumor and normal strains tested, a good correlation was observed between MGMT expression and cellular resistance to BCNU. The varying levels of expression of MGMT in human cancer cells found in this study should provide a molecular basis for MGMT expression among tumor strains from different tissue origin, the information of antitumor agents selection for chemotherapy of cancers.

• Radiation Oncology Journal
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• v.19 no.3
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• pp.245-251
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• 2001

Prupose : The genes involved on the suppression or radiation-induced apoptosis by genistein in K562 leukemia cell line was investigated. Materials and methods : K562 cells in exponential growth phase were irradiated with a linear accelerator at room temperature. For X-ray irradiation and drug treatment, cultures were prepared at $2\times10^5\;cells/mL$. The cells were irradiated with 10 Gy (Clinac 1800C, Varian, USA), Stock solutions of herbimycin A (HMA, Calbiochem, UK) and genistein (Calbiochem, UK) were prepared in dimethylsulfoxide (DMSO, Sigma, UK). After incubation at $37^{\circ}C$ for 24 h, PCR-select cDNA subtractive hybridization, dot hybridization, DNA sequencing and Northern hybridization were examined. Results : Smad6 gene was identified from the differentially expressed genes in K562 cells incubated with genistein which had been selected by PCR-select cDNA subtractive hybridization. The mRNA expression of Smad6 in K562 cells incubated with genistein was also higher than control group by Northern hybridization analysis. Conclusion : We have shown that Smad6 involved on the suppression of radiation-induced apoptosis by genistein in K562 leukemia cell line. It is plausible that the relationship between Smad6 and the suppression of radiation-induced apoptosis is essential for treatment development based on molecular targeting designed to modify radiation-induced apoptosis.

• Microbiology and Biotechnology Letters
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• v.30 no.1
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• pp.15-20
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• 2002

Diacylglycerol kinase (DGK) phosphorylates the second messenger diacylglycerol (DAG) to phosphatidic acid and it may play a role in signal transduction in Escherichia coli as well as in eukaryotic cells. In addition, DGK is important for microorganisms to adapt to several physiological stimuli. In Bacillus subtilis, the effect of stress on dgk transcription was examined by northern hybridization. The high level of dgk transcription was induced against high osmolarity, low pH value and low temperature. Transcriptional analysis revealed that the dgk gene and dgk upstream locus (ORF2, ORF3 and ORF4) were transcribed as a polycistronic mRNA to form an approximately 2.5 kb transcript.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1684-1690
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• 2005

Using mRNA differential display technique, we investigated differential gene expression in hybrids relative to their parents in a diallel cross involving four chicken breeds in order to provide an insight into the molecular basis of heterosis in chicken. The results indicated that there was extensive differential gene expression between chicken F1 hybrids and their parents which was classified into four kinds of patterns as following: (1) bands only detected in hybrid F1; (2) bands only absent in hybrid F1; (3) bands only detected in parent P1 or P2; (4) bands absent in parent P1 or P2. Forty-two differentially expressed cDNAs were cloned and sequenced, and their expression patterns were confirmed by Reverse-Northern dot blot. Sequence analysis and database searches revealed that genes showed differential expression between hybrid and parents were regulatory and functional genes involved in metabolism, mRNA splicing, transcriptional regulation, cell cycles and protein modification. These results indicated that hybridization between two parents can cause changes in expression of a variety of genes. In conclusion, that the altered pattern of gene expression in hybrids may be responsible for heterosis in chickens.

• Korean Journal of Biological Psychiatry
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• v.1 no.1
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• pp.79-87
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• 1994

For the purpose of evaluating the human leukocyte antigen(HLA) disease-association with bipolar disorder, HLA class I and class II allelic frequencies were assessed in 37 bipolar patients and were compared to the data from normal population. HLA class 1 typing was performed with microlymphocytotoxicity method while class II(DRB1) genotyping with reverse dot blot hybridization and sandwich method. Statistical analysis consisted of relative risk, Haldane's modified relative risk, Fisher's exact test and Bonferoni's corrected P. The results were as follows : 1) Bipolar patients showed increased allelic frequency of HLA A3 which has statistical significance. 2) Allelic frequencies of HLA B7, B14 and B54 were higher, while those of B51 and B55 were lower in bipolar patients, but they were not statistically significant. 3) Both of increased frequencies of DR2 in bipolar patients and DR15 in normal controls had statistical significance. The results of the present study suggested that some of HLA allelic types might be associated with bipolar disorder. To clarify the genetic influence of HLA to bipolar disorder, we should do consecutive study of bipolar disorder with new information about HLA system including alleles.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.1
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• pp.61-64
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• 2001

Ubiquitin can be covalently attached to cellular proteins as a post-translational modification rind is involved in metabolic stresses, such as bent shock and immune response. We have isolated and sequenced a cDNA encoding ubiquitin from the silkworm, Bombyx mori. The insert in the clone is 533 nucleotide long with an open reading frame of 387 nucleotides that encodes a protein of 129 amino acids with a molecular weight of 14.8 kDa. The amino acid sequence shared high homology with the ubiquitins known so far, The result of dot blot hybridization showed that the B. mori ubiquitin gene is up-regulated upon f. rofi infection, suggesting that the B. mori ubiquitin plays an immune-related role.

• Microbiology and Biotechnology Letters
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• v.25 no.5
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• pp.483-489
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• 1997

Sulforhodamine B (SRB) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, RNA dot blot and Northern hybridization analysis were performed to screen microorganisms for the production of anticancer agent. Among microorganisms tested, strain YP-1 was selected for its cytotoxicity and ability to reduce the level of c-myc RNA. Strain YP-1 was identified as Streptomyces endus. The anticancer material produced by Streptomyces endus YP-1 was sequentially purified by solvent extraction, silica gel column chromatograpby, preparative TLC and preparative HPLC. The cancer material identified as azalomycin B by the instrumental analyses such as $^{1}$H-NMR, $^{13}$C-NMR, Mass, IR and UV absorption. It was colorless amorphous powder and its molecular weight was 1025.278. Azalomycin B, produced by Streptomyces endus YP-1, showed anticancer activity against several human cancer cell lines and reduction of c-Myc protein level in Colo320 DM cells which was determined by Western blot analysis.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.177-177
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• 2003

Methylmercury (MeHg) is a well-known neurotoxicant that causes severe damage to the central nervous system in humans. Many reports have shown that MeHg is poisonous to human body through contaminated foods and has released into the environment. Despite many studies on the pathogenesis of MeHg-induced central neuropathy, no useful mechanism of toxicity has been established so far. In this study, suppressive subtractive hybridization (SSH) was performed to identify differentially expressed genes on human neuroblastoma cell line, SH-SY5Y treated with DMSO and MeHg (6.25 uM) for 6 hr. Differentially expressed cDNA clones were sequenced and were screened by dot blot to eliminate false positive clones. 13 of 35 screened genes were confirmed using real time RT-PCR. These genes include EB1,90-kDa heat-shock protein, chromosome condensation-related SMC-associated protein and brain peptide Al, etc. Analysis of these genes may provide an insight into the neurotoxic effects of MeHg in human neuronal cells and a possibility to develop more efficient and exact monitoring system of heavy metals as ubiquitous environmental pollutants.

• The Plant Pathology Journal
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• v.17 no.3
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• pp.164-168
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• 2001

Rice black-streaked dwarf virus (RBSDV) and Maize rough dwarf virus (MRDV) are closely related viruses. Since the two viruses produce identical symptoms on maize, barley, and wheat, diagnosis of infected plants is difficult. Previously, we reported that partial cDNA clones of RBSDV S5 and S6 from the Japanese isolate (RBSDV-H) have lower sequence homology to MRDV than do cDNA clones from other genomic segments. In order to test whether cDNA clones of RBSDV-H S5 and S6 can be used for molecular diagnosis, RBSDV field isolates from Korea and from Hokkaido, Japan were tested in dot blot hybridizations probed with RBSDV-H S5 and S6 cDNA colnes. Hybridization with these probes was more intense against the RBSDV genome than against the MRDV genome. Therefore, RBSDV-H S5 and S6 cDNA clones can be used to differentiate between the two viruses. Furthermore, RBSDV-H S5 and S6 clones reacted more strongly against the viruses from stunted maize plants from Korean fields than to MRDV, indicating that RBSDV may be the causal disease agent in maize plants in Korea.

• Molecules and Cells
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• v.26 no.4
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• pp.387-395
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• 2008

A novel Tc1-like transposable element has been identified as a new DNA transposon in the mud loach, Misgurnus mizolepis. The M. mizolepis Tc1-like transposon (MMTS) is comprised of inverted terminal repeats and a single gene that codes Tc1-like transposase. The deduced amino acid sequence of the transposase-encoding region of MMTS transposon contains motifs including DDE motif, which was previously recognized in other Tc1-like transposons. However, putative MMTS transposase has only 34-37% identity with well-known Tc1, PPTN, and S elements at the amino acid level. In dot-hybridization analysis used to measure the copy numbers of the MMTS transposon in genomes of the mud loach, it was shown that the MMTS transposon is present at about $3.36{\times}10^4$ copies per $2{\times}10^9$ bp, and accounts for approximately 0.027% of the mud loach genome. Here, we also describe novel MMTS-like transposons from the genomes of carp-like fishes, flatfish species, and cichlid fishes, which bear conserved inverted repeats flanking an apparently intact transposase gene. Additionally, BLAST searches and phylogenetic analysis indicated that MMTS-like transposons evolved uniquely in fishes, and comprise a new subfamily of Tc1-like transposons, with only modest similarity to Drosophila melanogaster (foldback element FB4, HB2, HB1), Xenopus laevis, Xenopus tropicalis, and Anopheles gambiae (Frisky).