• Molecules and Cells
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• 제42권4호
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• pp.301-312
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• 2019

Post-transcriptional regulation underlies the circadian control of gene expression and animal behaviors. However, the role of mRNA surveillance via the nonsense-mediated mRNA decay (NMD) pathway in circadian rhythms remains elusive. Here, we report that Drosophila NMD pathway acts in a subset of circadian pacemaker neurons to maintain robust 24 h rhythms of free-running locomotor activity. RNA interference-mediated depletion of key NMD factors in timeless-expressing clock cells decreased the amplitude of circadian locomotor behaviors. Transgenic manipulation of the NMD pathway in clock neurons expressing a neuropeptide PIGMENT-DISPERSING FACTOR (PDF) was sufficient to dampen or lengthen free-running locomotor rhythms. Confocal imaging of a transgenic NMD reporter revealed that arrhythmic Clock mutants exhibited stronger NMD activity in PDF-expressing neurons than wild-type. We further found that hypomorphic mutations in Suppressor with morphogenetic effect on genitalia 5 (Smg5) or Smg6 impaired circadian behaviors. These NMD mutants normally developed PDF-expressing clock neurons and displayed daily oscillations in the transcript levels of core clock genes. By contrast, the loss of Smg5 or Smg6 function affected the relative transcript levels of cAMP response element-binding protein B (CrebB) in an isoform-specific manner. Moreover, the overexpression of a transcriptional repressor form of CrebB rescued free-running locomotor rhythms in Smg5-depleted flies. These data demonstrate that CrebB is a rate-limiting substrate of the genetic NMD pathway important for the behavioral output of circadian clocks in Drosophila.

• BMB Reports
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• 제55권7호
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• pp.348-353
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• 2022

Gastrointestinal cancer is associated with a high mortality rate. Here, we report that the splice variant of NRP/B contributes to tumorigenic activity in highly malignant gastric cancer through dissociation from the tumor repressor, HDAC5. NRP/B mRNA expression is significantly higher in the human gastric cancer tissues than in the normal tissues. Further, high levels of both the NRP/B splice variant and Lgr5, but not the full-length protein, are found in highly tumorigenic gastric tumor cells, but not in non-tumorigenic cells. The loss of NRP/B markedly inhibits cell migration and invasion, which reduces tumor formation in vivo. Importantly, the inhibition of alternative splicing increases the levels of NRP/B-1 mRNA and protein in AGS cells. The ectopic expression of full-length NRP/B exhibits tumor-suppressive activity, whereas NRP/B-2 induces the noninvasive human gastric cancer cells tumorigenesis. The splice variant NRP/B-2 which loses the capacity to interact with tumor repressors promoted oncogenic activity, suggesting that the BTB/POZ domain in the N-terminus has a crucial role in the suppression of gastric cancer. Therefore, the regulation of alternative splicing of the NRP/B gene is a potential novel target for the treatment of gastrointestinal cancer.

• Mycobiology
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• 제51권5호
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• pp.372-378
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• 2023

Lkh1, a LAMMER kinase homolog in the fission yeast Schizosaccharomyces pombe, acts as a negative regulator of filamentous growth and flocculation. It is also involved in the response to oxidative stress. The lkh1-deletion mutant displays slower cell growth, shorter cell size, and abnormal DNA content compared to the wild type. These phenotypes suggest that Lkh1 controls cell size and cell cycle progression. When we performed microarray analysis using the lkh1-deletion mutant, we found that only four of the up-regulated genes in the lkh1-deletion were associated with the cell cycle. Interestingly, all of these genes are regulated by the Mlu1 cell cycle box binding factor (MBF), which is a transcription complex responsible for regulating the expression of cell cycle genes during the G1/S phase. Transcription analyses of the MBF-dependent cell-cycle genes, including negative feedback regulators, confirmed the up-regulation of these genes by the deletion of lkh1. Pull-down assay confirmed the interaction between Lkh1 and Yox1, which is a negative feedback regulator of MBF. This result supports the involvement of LAMMER kinase in cell cycle regulation by modulating MBF activity. In vitro kinase assay and NetPhosK 2.0 analysis with the Yox1T40,41A mutant allele revealed that T40 and T41 residues are the phosphorylation sites mediated by Lkh1. These sites affect the G1/S cell cycle progression of fission yeast by modulating the activity of the MBF complex.

• Tuberculosis and Respiratory Diseases
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• 제41권5호
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• pp.462-474
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• 1994

연구배경 : 급성 폐손상에서는 호중구가 조직손상에 중요한 역할을 하는데 호중구는 외부자극에 의해 단핵식세포에서 분비되는 여러 화학주화인자에 인하여 국소염증부위로 이동하며, 이중 대표적인 물질이 호중구에 비교적 특이적으로 작용하는 IL-8이다. IL-8은 호중구에 대한 주화작용외에 호중구 표면에 유착성 분자의 발현을 증가시키고 호중구 자체를 활성화 시키는 등 직,간접적으로 염증반응에 관여한다. 그러나 아직까지 급성폐손상의 표본인 성인성 호흡곤란증후군의 가장 흔한 원인인 내독소에 의한 단핵식세포에서 IL-8의 분자생물학적 조절기전에 대한 연구는 많지 않은 설정이다. 방법 : 정상인의 페포대식세포와 말초혈액 단핵세포를 분리하여 내독소에 의한 IL-8 mRNA 발현양상을 관찰하기 위하여 내독소의 여러 농도와 배양시간에 따라 IL-8 mRNA에 대한 Northern blot analysis를 시행하였다. 내독소에 의한 IL-8 유전자 발현의 분자생물학적 조절기전을 규명하기 위해 actinomycin D와 cycloheximide로 전처치한 후 내독소에 의한 IL-8 mRNA와 배양액에서 면역반응성 IL-8을 측정하기위해 각각 Northern blot analysis와 ELISA를 시행하였다. 결과: 1) 폐포대식세포와 말초혈액 단핵세포 모두에서 내독소에 의한 IL-8 mRNA의 발현은 내독소 1 ng/ml의 농도에서부터 증가되었으며 내독소 농도의 증가에 따라 증가되었다. 또한 내독소에 의한 IL-8 mRNA의 발현은 내독소 투여 2시간후부터 증가되기 시작하여 24시간까지 지속되었으며 폐포대식세포에서는 8시간, 말초혈액 단핵세포에서는 4시간에 각각 정점을 이루었다. 2) actinomycin D는 페포대식세포와 말초혈액 단핵세포 모두에서 IL-8 유전자 발현을 mRNA와 단백질 수준에서 억제시켰다. 3) cycloheximide는 폐포대식세포와 말초혈액 단핵세포 모두에서 IL-8 유전자 발현을 단백질 수준에서는 억제시켰으나 mRNA발현은 폐포대식세포에서는 약간 증가 시켰고 말초혈액 단핵세포에서는 약간 억제시켰다. 결론 : 폐포대식세포와 말초혈액 단핵세포 모두에서 내독소에 의해 IL-8 mRNA의 발현과 IL-8 단백의 분비가 증가되었는데 이는 일부 전사이전 수준에서 (pretranslational level) 조절되며 폐포대식세포에서는 de novo 단백합성과는 관계가 없고 불안정한 억제인자 (labile repressor)의 조절을 받고 있고 말초혈액 단핵세포에서는 지속적인 de novo 단백합성이 중요할 것으로 생각된다.

• BMB Reports
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• 제40권5호
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• pp.757-764
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• 2007

Marbling of cattle meat is dependent on the coordinated expression of multiple genes. Cattle dramatically increase their intramuscular fat content in the longissimus dorsi muscle between 12 and 27 months of age. We used the annealing control primer (ACP)-differential display RT-PCR method to identify differentially expressed genes (DEGs) that may participate in the development of intramuscular fat between early (12 months old) and late fattening stages (27 months old). Using 20 arbitrary ACP primers, we identified and sequenced 14 DEGs. BLAST searches revealed that expression of the MDH, PI4-K, ferritin, ICER, NID-2, WDNMI, telethonin, filamin, and desmin (DES) genes increased while that of GAPD, COP VII, ACTA1, CamK II, and nebulin decreased during the late fattening stage. The results of functional categorization using the Gene Ontology database for 14 known genes indicated that MDH, GAPD, and COP VII are involved in metabolic pathways such as glycolysis and the TCA cycle, whereas telethonin, filamin, nebulin, desmin, and ACTA1 contribute to the muscle contractile apparatus, and PI4-K, CamK II, and ICER have roles in signal transduction pathways regulated by growth factor or hormones. The final three genes, NID-2, WDNMI, and ferritin, are involved in iron transport and extracellular protein inhibition. The expression patterns were confirmed for seven genes (MDH, PI4-K, ferritin, ICER, nebulin, WDNMI, and telethonin) using real-time PCR. We found that the novel transcription repressor ICER gene was highly expressed in the late fattening stage and during bovine preadipocyte differentiation. This information may be helpful in selecting candidate genes that participate in intramuscular fat development in cattle.

• 한국식품과학회지
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• 제31권1호
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• pp.246-251
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• 1999

다양한 유전형질을 갖고 있는 E. coli WP series, E. coli TK series 및 E. coli GW series 변이주들을 이용하여 chloropropanol의 변이원성 기구를 해석하였다. 3종류의 chloropropanol 모두 E. coli WP2s와 WP67에서는 돌연변이활성이 나타났으나 E. coli WP2와 CM611에서는 변이원성이 거의 나타나지 않았으며 2,3-DCP>3-MCPD>1,3-DCP 순으로 돌연변이 활성을 나타내었다. E. coli WP2s와 비교하여 E. coli WP2 $(WP2s\;uvrA^+)$에서 돌연변이활성이 크게 감소한 반면 균 생존율이 상당히 증가한 결과로부터 절제수복에 의해 쉽게 제거되는 DNA 손상임을 확인할 수 있었으며, E. coli CM611(WP2s lexA102)에서 돌연변이활성 및 균 생존율 모두 상당히 감소된 결과로부터 이들 물질에 의한 주요 DNA 손상이 SOS 수복 의존성임이 시사되었다. 또한 E. coli TK610 (umuC)에서의 돌연변이율과 균 생존율은 그 대조 균주인 E. coli TK603 $(umuC^+)$에 비하여 상당히 감소하여 chloropropanol에 의한 돌연변이 유발은 umuC가 관여하는 SOS 수복을 통하여 일어나는 것으로 확인되었다. E. coli GW1105 [lexA3 (Ind)]와 GW1107 [lexA51 (Def)] 두 균주에서 ${\beta}-galactosidase$의 활성이 chloropropnaol 첨가에 의해 변화하지 않았기 때문에 SOS 반응의 repressor로 작용하는 LexA에 대하여 chloropropnol이 직접적으로 영향을 미치지 않는 것으로 나타났다. 따라서 chloropropanol에 의한 DNA 손상은 가장 기본적인 수복계라 할 수 있는 절제수복에 의하여 제거될 수 있으며, 돌연변이의 발생은 주로 SOS 수복계를 통하여 일어남을 확인할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.496-510
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• 2007

This paper describes the use of a discrete mathematical model to represent the basic mechanisms of regulation of the bacteria E. coli in batch fermentation. The specific phenomena studied were the changes in metabolism and genetic regulation when the bacteria use three different carbon substrates (glucose, glycerol, and acetate). The model correctly predicts the behavior of E. coli vis-a-vis substrate mixtures. In a mixture of glucose, glycerol, and acetate, it prefers glucose, then glycerol, and finally acetate. The model included 67 nodes; 28 were genes, 20 enzymes, and 19 regulators/biochemical compounds. The model represents both the genetic regulation and metabolic networks in an integrated form, which is how they function biologically. This is one of the first attempts to include both of these networks in one model. Previously, discrete mathematical models were used only to describe genetic regulation networks. The study of the network dynamics generated 8 $(2^3)$ fixed points, one for each nutrient configuration (substrate mixture) in the medium. The fixed points of the discrete model reflect the phenotypes described. Gene expression and the patterns of the metabolic fluxes generated are described accurately. The activation of the gene regulation network depends basically on the presence of glucose and glycerol. The model predicts the behavior when mixed carbon sources are utilized as well as when there is no carbon source present. Fictitious jokers (Joker1, Joker2, and Repressor SdhC) had to be created to control 12 genes whose regulation mechanism is unknown, since glycerol and glucose do not act directly on the genes. The approach presented in this paper is particularly useful to investigate potential unknown gene regulation mechanisms; such a novel approach can also be used to describe other gene regulation situations such as the comparison between non-recombinant and recombinant yeast strain, producing recombinant proteins, presently under investigation in our group.

• 한국약용작물학회지
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• 제20권5호
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• pp.359-364
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• 2012

This study were carried out to find bolting response of cultivation in different regions and to isolate FLC (FLOWERING LOCUS C) homologs in Angelica gigas Nakai. The mean temperature of different regions, ordering in altitude, were as follows: 100 m > 350 m > 530 m > 700 m. The largest amount of rainfall was occurred in the region of 350 m while the longest time of sunshine was occurred in the region of 100 m. The content of soil chemical properties in regions showed pH 6.2 ~ 7.4, T-N 0.17 ~ 26, organic mater $1{\sim}32gkg^{-1}$, $P_2O_5$ ${151{\sim}664_{mgkg}}^{-1}$, exchangeable potassium and calcium and magnesium were 0.78 ~ 1.15, 3.9 ~ 10.0, ${0.7{\sim}3.2_{cmol}}^{+kg-1}$. L5 line of A. gigas was occurred in bolting at all regions, but the bolting ratio was 60.0% in 700 m region with non-mulching treatment. Manchu of A. gigas was not occurred in bolting at all regions. The accumulation bolting ratio of L5 line by non-mulching was higher than that of mulching as 90.4% and 72.8% in 100 m region. The MADS-box transcription factor FLC is one of the well-known examples as a strong floral repressor. We decided to isolate FLC homologs from A. gigas as a starting point of flowering mechanism research of this plant. We have isolated two RT-PCR products which showed very high amino acid sequence homology to Arabidopsis FLC.

• Molecules and Cells
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• 제38권3호
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• pp.259-266
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• 2015

The regulation of flowering time has crucial implications for plant fitness. MicroRNA156 (miR156) represses the floral transition in Arabidopsis thaliana, but the mechanisms regulating its transcription remain unclear. Here, we show that two AGAMOUS-like proteins, AGL15 and AGL18, act as positive regulators of the expression of MIR156. Small RNA northern blot analysis revealed a significant decrease in the levels of mature miR156 in agl15 agl18 double mutants, but not in the single mutants, suggesting that AGL15 and AGL18 co-regulate miR156 expression. Histochemical analysis further indicated that the double mutants showed a reduction in MIR156 promoter strength. The double mutants also showed reduced abundance of pri-miR156a and pri-miR156c, two of the primary transcripts from MIR156 genes. Electrophoretic mobility shift assays demonstrated that AGL15 directly associated with the CArG motifs in the MIR156a/c promoters. AGL18 did not show binding affinity to the CArG motifs, but pull-down and yeast two-hybrid assays showed that AGL18 forms a heterodimer with AGL15. GFP reporter assays and bimolecular fluorescence complementation (BiFC) showed that AGL15 and AGL18 co-localize in the nucleus and confirmed their in vivo interaction. Overexpression of miR156 did not affect the levels of AGL15 and AGL18 transcripts. Taking these data together, we present a model for the transcriptional regulation of MIR156. In this model, AGL15 and AGL18 may form a complex along with other proteins, and bind to the CArG motifs of the promoters of MIR156 to activate the MIR156 expression.

• Asian Pacific Journal of Cancer Prevention
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• 제16권9호
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• pp.3811-3816
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• 2015

Background: Hairy and enhancer of split 1 (Hes-1) protein is a downstream target of Notch signaling and is a basic helix-loop-helix transcriptional repressor. However, definitive evidence for a role in hepatocellular carcinoma (HCC) cells has not been reported. Here, Hes-1 was revealed to an important component of the Notch signaling cascade in HCC cell lines possessing different potential for lung metastasis. Materials and Methods: RNAi mediated by plasmid constructs was used to analyze the role of Hes-1 in MHCC-97L HCC cells by assessing proliferation, apoptosis, cell migration and matrigel invasion following transfection. Hes-1 protein expression analysis in HCC tissue was also conducted by immunohistochemistry. Results: Our studies revealed that Hes-1 was decreased in HCC cell lines with higher lung metastasis potential at both the mRNA and protein levels. Down-regulation of the Hes-1 gene in MHCC-97L cells resulted in increased cell proliferation, reduced apoptosis and increased migration and invasion. Conclusions: Hes-1 has potential prognostic value in post-surgical HCC patients and may be an independent prognostic indicator for overall survival and tumor recurrence. These findings have important implications for understanding the mechanisms by which Hes-1 participates in tumor proliferation and invasion.