• Development and Reproduction
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• v.16 no.1
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• pp.59-67
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• 2012

Previously, we found that $Zap70$ (Zeta-chain-associated protein kinase) expressed in the mouse oocytes and played significant role in completion of meiosis specifically at MI-MII (metaphase I-II) transition. Microinjection of $Zap70$ dsRNA into the cytoplasm of germinal vesicle oocyte resulted in MI arrest, and exhibited abnormalities in their spindles and chromosome configurations. The purpose of this study was to determine the mechanisms of action of $Zap70$ in oocyte maturation by evaluating downstream signal networking after $Zap70$ RNAi (RNA interference). The probe hybridization and data analysis were used by Affymetrix Gene Chip Mouse Genome 430 2.0 array and GenPlex 3.0 (ISTECH, Korea) software, respectively. Total 1,152 genes were up (n=366) and down (n=786) regulated after $Zap70$ RNAi. Among those genes changed, we confirmed the expressional changes of the genes involved in the regulation of actin cytoskeleton and MAPK (mitogen-activated protein kinase) signaling pathway, since the phenotypes of $Zap70$ RNAi in oocytes were found in the changes in the chromosome separation and spindle structures. We confirmed the changes in gene expression in the actin skeletal system as well as in the MAPK signaling pathway, and concluded that these changes are main cause of the aberrant chromosome arrangement and abnormal spindles after $Zap70$ RNAi.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.166-171
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• 2013

While high-dose ionizing radiation results in long term cellular cytotoxicity, chronic low-dose (<0.2 Gy) of X- or ${\gamma}$-ray irradiation can be beneficial to living organisms by inducing radiation hormesis, stimulating immune function, and adaptive responses. During chronic low-dose-rate radiation (LDR) exposure, whole body of mice is exposed to radiation, however, it remains unclear if LDR causes changes in gene expression of the whole brain. Therefore, we aim to investigate expressed genes (EGs) and signaling pathways specifically regulated by LDR-irradiation ($^{137}Cs$, a cumulative dose of 1.7 Gy for total 100 days) in the whole brain. Using microarray analysis of whole brain RNA extracts harvested from ICR and AKR/J mice after LDR-irradiation, we discovered that two mice strains displayed distinct gene regulation patterns upon LDR-irradiation. In ICR mice, genes involved in ion transport, transition metal ion transport, and developmental cell growth were turned on while, in AKR/J mice, genes involved in sensory perception, cognition, olfactory transduction, G-protein coupled receptor pathways, inflammatory response, proteolysis, and base excision repair were found to be affected by LDR. We validated LDR-sensitive EGs by qPCR and confirmed specific upregulation of S100a7a, Olfr624, and Gm4868 genes in AKR/J mice whole brain. Therefore, our data provide the first report of genetic changes regulated by LDR in the mouse whole brain, which may affect several aspects of brain function.

• Animal cells and systems
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• v.13 no.4
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• pp.371-379
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• 2009

The endocannabinoid system (ECS) plays a key role in the regulation of appetite, body weight and metabolism. We undertook the present study to further clarify the regulation of the cannabinoid CB1 receptor (CB1, CNR1) in human adipose tissue in obesity. CB1 receptor mRNA expression was ~1.6-fold (p<0.004) and 1.9-fold higher (P<0.05) in subcutaneous adipocytes from obese compared to non-obese subjects in microarray and quantitative real-time PCR studies, respectively. Higher CB1 receptor mRNA expression levels in both adipose tissue (~1.2 fold, P<0.05) and adipocytes (~2 fold, P<0.01) were observed in samples from visceral compared to subcutaneous depots collected from 22 obese individuals. Immunofluorescence confocal microscopy demonstrated the presence of CB1 receptor on adipocytes and also adipose tissue macrophages. These data indicate that adipocyte CB1 receptor is up-regulated in human obesity and visceral adipose tissue and also suggest a potential role for the ECS in modulating immune/inflammation as well as fat metabolism in adipose tissue.

• Molecules and Cells
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• v.25 no.3
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• pp.368-375
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• 2008

Approximately 120 UDP-glycosyltransferases (UGTs), which are classified into 14 distinct groups (A to N), have been annotated in the Arabidopsis genome. UGTs catalyze the transfer of sugars to various acceptor molecules including flavonoids. Previously, UGT71C1 was shown to glycosylate the 3-OH of hydroxycinnamates and flavonoids in vitro. Such secondary metabolites are known to play important roles in plant growth and development. To help define the role of UGT71C1 in planta, we investigated its expression patterns, and isolated and characterized a loss-of-function mutation in the UGT71C1 gene (named ugt71c1-1). Our analyses by quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR), microarray data mining, and histochemical detection of GUS activity driven by the UGT71C1 promoter region, revealed the tissue-specific expression patterns of UGT71C1 with highest expression in roots. Interestingly, upon treatment with methyl viologen (MV, paraquat), ugt71c1-1 plants displayed enhanced resistance to oxidative stress, and ROS scavenging activity was higher than normal. Metabolite profiling revealed that the levels of two major glycosides of quercetin and kaempferol were reduced in ugt71c1-1 plants. In addition, when exposed to MV-induced oxidative stress, eight representative ROS response genes were expressed at lower levels in ugt71c1-1 plants, indicating that ugt71c1-1 probably has higher non-enzymatic antioxidant activity. Taken together, our results indicate that ugt71c1-1 has increased resistance to oxidative stress, suggesting that UGT71C1 plays a role in some glycosylation pathways affecting secondary metabolites such as flavonoids in response to oxidative stress.

• Journal of Microbiology and Biotechnology
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• v.23 no.4
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• pp.451-458
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• 2013

The human gastric pathogen Helicobacter pylori (Hp) has been considered a microaerophile. However, we recently reported that, when supplied with 10% $CO_2$, Hp growth is stimulated by an atmospheric level of $O_2$, suggesting that Hp is a capnophilic aerobe. In this study, we investigated the effects of aerobic $O_2$ tension on Hp cells by comparing gene expression profiles of cultures grown under microaerobic and aerobic conditions in the presence of 10% $CO_2$. The results showed that overall differences in gene expression in Hp cells grown under the two $O_2$ conditions were predominantly growth-phase-dependent. At 6 h, numerous genes were down-regulated under the aerobic condition, accounting for our previous observation that Hp growth was retarded under this condition. At 36 h, however, diverse groups of genes involved in energy metabolism, cellular processes, transport, and cell envelope synthesis were highly up- or down-regulated under the aerobic condition, indicating a progression of the cultures from the log phase to the stationary phase. The expression of several oxidative stress-associated genes including tagD, katA, and rocF was induced in response to aerobic $O_2$ level, whereas trxA, trxB, and ahpC remained unchanged. Altogether, these data demonstrate that aerobic $O_2$ tension is not detrimental to Hp cells but stimulates Hp growth, supporting our previous finding that Hp may be an aerobic bacterium that requires a high $CO_2$ level for its growth.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.409-414
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• 2013

Naive Bayesian classifiers are a powerful and well-known type of classifiers that can be easily induced from a dataset of sample cases. However, the strong conditional independence assumptions can sometimes lead to weak classification performance. Normally, naive Bayesian classifiers use Gaussian distributions to handle continuous attributes and to represent the likelihood of the features conditioned on the classes. The probability density of attributes, however, is not always well fitted by a Gaussian distribution. Another eminent type of classifier is the neuro-fuzzy classifier, which can learn fuzzy rules and fuzzy sets using supervised learning. Since there are specific structural similarities between a neuro-fuzzy classifier and a naive Bayesian classifier, the purpose of this study is to apply learning distribution graphs constructed by a neuro-fuzzy network to naive Bayesian classifiers. We compare the Gaussian distribution graphs with the fuzzy distribution graphs for the naive Bayesian classifier. We applied these two types of distribution graphs to classify leukemia and colon DNA microarray data sets. The results demonstrate that a naive Bayesian classifier with fuzzy distribution graphs is more reliable than that with Gaussian distribution graphs.

• International Journal of Oral Biology
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• v.36 no.4
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• pp.179-185
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• 2011

MicroRNAs (miRNAs) are small non-coding RNAs that mediate gene expression at the post-transcriptional level by degrading or repressing targeted mRNAs. These molecules are about 21-25 nucleotides in length and exert their effects by binding to partially complementary sites in mRNAs, predominantly in the 3'-untranslated region (3'-UTR). Recent evidence has demonstrated that miRNAs can function as oncogenes or tumor suppressors through the modulation of multiple oncogenic cellular processes in cancer development, including initiation, cell proliferation, apoptosis, invasion and metastasis. In our present study, we examined the expression profile of miRNAs related to oral cancer cell growth inhibition using normal human oral keratinocytes (NHOK) and YD-38 human oral cancer cells. By miRNA microassay analysis, 40 and 31 miRNAs among the 1,769 examined were found to be up- and down-regulated in YD-38 cells compared with NHOK cells, respectively. Using qRT-PCR analysis, the expression levels of miR-30a and miR-1246 were found to be increased in YD-38 cells compared with NHOK cells, whereas miR-203 and miR-125a were observed to be decreased. Importantly, the overexpression of miR-203 and miR-125a significantly inhibited the growth of YD-38 cells. This finding and the microarray data indicate the involvement of specific miRNAs in the development and progression of oral cancer.

• Clinical and Experimental Reproductive Medicine
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• v.38 no.2
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• pp.68-74
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• 2011

Objective: Previously, we found that oocyte specific homeobox (Obox) 4 plays significant role in completion of meiosis specifically at meiosis I-meiosis II (MI-MII) transition. The purpose of this study was to determine the mechanism of action of $Obox4$ in oocyte maturation by evaluating downstream signal networking. Methods: The $Obox4$ dsRNA was prepared by $in$ $vitro$ transcription and microinjected into the cytoplasm of germinal vesicle oocytes followed by $in$ $vitro$ maturation in the presence or absence of 0.2 mM 3-isobutyl-1-metyl-xanthine. Total RNA was extracted from 200 oocytes of each group using a PicoPure RNA isolation kit then amplified two-rounds. The probe hybridization and data analysis were used by Affymetrix Gene-Chip$^{(R)}$ Mouse Genome 430 2.0 array and GenPlex 3.0 (ISTECH, Korea) software, respectively. Results: Total 424 genes were up (n=80) and down (n=344) regulated after $Obox4$ RNA interference (RNAi). Genes mainly related to metabolic pathways and mitogen-activated protein kinase (MAPK) signaling pathway was changed. Among the protein kinase C (PKC) isoforms, PKC-alpha, beta, gamma were down-regulated and especially the MAPK signaling pathway PKC-gamma was dramatically decreased by $Obox4$ RNAi. In the cell cycle pathway, we evaluated the expression of genes involved in regulation of chromosome separation, and found that these genes were down-regulated. It may cause the aberrant chromosome segregation during MI-MII transition. Conclusion: From the results of this study, it is concluded that $Obox4$ is important upstream regulator of the PKC and anaphase-promoting complex action for maintaining intact germinal vesicle.

• Journal of Life Science
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• v.22 no.10
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• pp.1415-1419
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• 2012

Thymosin ${\beta}4$ ($T{\beta}4$) has been reported to be overexpressed in CD133-positive colorectal cancer stem cells. We analyzed the relationship between $T{\beta}4$ and CD133-positive stem cells in normal stomach by examining the expression patterns of $T{\beta}4$ and CD133 in normal stomach tissues by immunohistochemical staining; co-localization of $T{\beta}4$ and CD133 was studied by immunofluorescence and confocal laser-scanning microscopy. Both $T{\beta}4$ and CD133 were expressed in stomach glands and showed similar expression patterns. Immunofluorescence staining of $T{\beta}4$ and CD133 showed that the expression of $T{\beta}4$ and CD133 was co-localized. In summary, both $T{\beta}4$ and CD133 were expressed in glands of normal stomachs and expression patterns were co-localized. These data suggest that $T{\beta}4$ expression is strongly related to CD133 expression.

• Environmental Mutagens and Carcinogens
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• v.25 no.1
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• pp.40-46
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• 2005

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) displays high toxicity in animals and has been implicated in human carcinogenesis. Although the mechanism of carcinogenesis by TCDD is unclear, it is considered to be a non-genotoxic compound and tumor promoter. In our experiment, we investigated the effects of TCDD on gene expression in mouse skin carcinogenesis. We used cDNA microarray to detect the differential gene expression in tumors induced in hairless mouse skin by MNNG plus TCDD protocol. We found that erb-2, c-ets2 and p27$^{kip1}$ were significantly up-regulated, but TNFR2, AKT-l, integrin $\beta$l, maspin, IGF-l, c-raf-l, Rb were significantly down-regulated, in tumor region, respectively. We also found that the expression of 53 genes involved in cen cycle, signal transduction, apoptosis, adhesion molecule, angiogenesis, and invasion, were changed two fold more, in tumor surrounding region. These data suggest that TCDD alters the expression of a large array of genes involved in apoptosis, cytokine production and angiogenesis in mouse skin carcinogenesis.