• Asian Pacific Journal of Cancer Prevention
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• 제16권15호
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• pp.6753-6759
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• 2015

Background: Loss of function of the p53 gene is implicated in defective apoptotic responses of tumors to chemotherapy. Although the pro-apoptotic roles of eugenol and capsaicin have been amply reported, their dependence on p53 for apoptosis induction in gastric cancer cells is not well elucidated. The aim of the study was to elucidate the role of p53 in the induction of apoptosis by eugenol and capsaicin in a human gastric cancer cell line, AGS. Materials and Methods: AGS cells were incubated with or without various concentrations of capsaicin and eugenol for 12 hrs, in the presence and absence of p53 siRNA. Cell cycling, annexin V and expression of apoptosis related proteins Bax, Bcl-2 ratio, p21, cyt c-caspase-9 association, caspase-3 and caspase-8 were studied. Results: In the presence of p53, capsaicin was a more potent pro-apoptotic agent than eugenol. However, silencing of p53 significantly abrogated apoptosis induced by capsaicin but not that by eugenol. Western blot analysis of pro-apoptotic markers revealed that as opposed to capsaicin, eugenol could induce caspase-8 and caspase-3 even in the absence of p53. Conclusions: Unlike capsaicin, eugenol could induce apoptosis both in presence and absence of functional p53. Agents which can induce apoptosis irrespective of the cellular p53 status have immense scope for development as potential anticancer agents.

• BMB Reports
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• 제51권1호
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• pp.21-26
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• 2018

Delta-like ligand 4 (DLL4) expression in endothelial cells is intimately associated with angiogenic sprouting and vascular remodeling, but the precise mechanism of transcriptional regulation of DLL4 remains incompletely understood. Here, we showed that LIM-domain binding protein 2 (LDB2) plays an important role in regulating basal DLL4 and VEGF-induced DLL4 expression. Knockdown of LDB2 using siRNA enhanced endothelial sprouting and tubular network formation in vitro. Injection of ldb2-morpholino resulted in defective development of intersegmental vessels in zebrafish. Reduction or over-expression of LDB2 in endothelial cells decreased or increased DLL4 expression. LDB2 regulated DLL4 promoter activity by binding to its promoter region and the same promoter region was occupied and regulated by the LMO2/TAL1/GATA2 complex. Interestingly, LDB2 also mediated VEGF-induced DLL4 expression in endothelial cells. The regulation of DLL4 by the LDB2 complex provides a novel mechanism of DLL4 transcriptional control that may be exploited to develop therapeutics for aberrant vascular remodeling.

• 한국동물생명공학회지
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• 제36권4호
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• pp.307-313
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• 2021

Traf4 (Tumor necrosis factor Receptor Associated Factor 4) is a member of the tumor necrosis factor receptor (TNFR) - associated factors (TRAFs) family. TRAF4 is overexpressed in tumor cells such as breast cancer and associated with cytoskeleton and membrane fraction. Interestingly, TRAF4 was localized with tight junctions (TJs) proteins including OCLN and TJP1 in mammary epithelial cells. However, the expression patterns and biological function of Traf4 were not examined in preimplantation mouse embryos although Traf4-deficient mouse showed embryonic lethality or various dramatic malformation. In this study, we examined the temporal and spatial expression patterns of mouse Traf4 during preimplantation development by qRT-PCR and immunostaining, and its biological function by using siRNA injection. We found upregulation of Traf4 from the 8-cell stage onwards and apical region of cell - cell contact sites at morula and blastocyst embryos. Moreover, Traf4 knockdown led to defective TJs without alteration of genes associated with TJ assembly but elevated p21 expression at the KD morula. Taken together, Traf4 is required for TJs assembly and cell proliferation during morula to blastocyst transition.

• Tuberculosis and Respiratory Diseases
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• 제47권1호
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• pp.13-25
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• 1999

연구배경: 결핵은 대식세포와 T 림프구가 주로 관여하는 세포성 면역에 의하여 발생되는 대표적인 질환이다. 특히 Th1 또는 Th2 림프구 가농에 의하여 이루어지는 면역반응의 결과에 따라 결핵균에 대한 감수성 또는 저항성이 결정된다. 본 연구는 치료실패 폐결핵환자의 말초혈액단핵구를 PPD 또는 수용성 TSP 항원으로 결핵의 보호면역과 관계가 있는 Th1 반응과 결핵의 감수성과 관계가 있다고 알려진 Th2 반응을 관찰하였다. 방법: 수용성 TSP 항원과 대조항원인 PPD 항원으로 건강인, 폐결핵으로 진단되어 단기치료지침에 의하여 균음 전화된 치료반응 환자 및 치료실패 환자의 말초혈액 단핵구를 대상으로 단핵구 증식반응과 Th1 반응 및 Th2 반응과 각각 관계가 있는 IFN-$\gamma$ 및 RANTES와 MCP-1 mRNA 발현 빈도를 역전사효소 중합효소연쇄반응으로 조사하였다. 결과: PPD 피부반응 양성 건강인 모두는 PPD 또는 TSP 항원에 의하여 자극지수 4 이상의 유의한 증식반응을 보였으나 PPD 음성 건강인 모두는 PPD 또는 TSP 항원에 의하여 자극지수 4 미만의 증식반응을 보였다. 치유된 환자는 80%의 증식반응을 보였으나 치료실패 환자는 PPD 에 의하여 30.8% 그리고 TSP 항원에 의하여 15.4% 만이 자극지수 4 이상의 유의한 증식반응을 보였다. 치유된 환자의 1FN-$\gamma$ mRNA 발현빈도는 90.0% 이었으나 치료실패 환자는 PPD 또는 TSP 항원에 의하여 23.1% 만이 유도되었다. PPD 양성 건강인의 말초혈액단핵구를 PPD, TSP 또는 PHA로 자극하면 RANTES가 모두 발현되었다. 치료실패 환자, PPD 피부반응 음성 및 치유된 환자를 PPD로 발현을 유도한 경우 각각 76.9%, 80.0%로 대상간에 차이가 없었다. 그러나 TSP 항원으로 유도하면 건강 대조군 및 치유된 환자에 비하여 치료실패 환자는 46.2%로 발현빈도가 유의하게 감소되었다. 또한 PHA로 자극한 경우에서도 치료실패 환자는 69.2%로 감소하여 IFN-$\gamma$ mRNA 발현율 감소 경향과 유사하였다. 치료실패 환자는 MCP-1의 발현빈도가 치유된 환자에 비하여 유의하게 증가되었다. 치료실패 환자에 있어서 PHA 자극의 53.8% 보다는 PPD 또는 TSP로 자극한 경우에 발현빈도가 각각 76.9%로 높았다. 그러나 PPD 양성 건강인 및 치유된 환자는 PPD 또는 TSP로 유도한 결과 40% 이었으며 PHA로 유도한 경우는 각각 80%와 90%로 결핵균 항원에서 낮은 발현 빈도를 보여 치료실패 환자와 상반되는 결과를 보였다. 결론: 치료실패 환자는 PPD 피부반응 양성 건강인 및 치유된 환자에 비하여 말초혈액단핵구의 증식능, 1FN-$\gamma$ 및 RANTES mRNA 발현빈도가 현저히 감소되어 Th1 반응이 억제되어 있었다. 반면에 MCP-1 mRNA의 발현빈도는 현저히 증가되어 Th2 반응의 증가로 결핵균 사균 능력이 치료실패 환자는 감소되어 있다고 생각된다.

• Molecules and Cells
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• 제22권3호
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• pp.343-352
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• 2006

Sialic acid is a sugar typically found at the N-glycan termini of glycoproteins in mammalian cells. Lec3 CHO cell mutants are deficient in epimerase activity, due to a defect in the gene that encodes a bifunctional UDP-GlcNAc 2-epimerase/ManNAc kinase (GNE). Sialic acid modification on the cell surface is partially affected in these cells. We have mutagenized Lec3 CHO cells and isolated six mutants (termed C2m) deficient in the cell surface expression of polysialic acid (PSA). Mutant C2m9 was partially defective in expression of cell-surface PSA and wheat germ agglutinin (WGA) binding, while in the other five mutants, both cell-surface PSA and WGA binding were undetectable. PSA expression was restored by complementation with the gene encoding the CMP-sialic acid transporter (CST), indicating that CST mutations were responsible for the phenotypes of the C2m cells. We characterized the CST mutations in these cells by Northern blotting and RT-PCR. C2m9 and C2m45 carried missense mutations resulting in glycine to glutamate substitutions at amino acids 217 (G217E) and 256 (G256E), respectively. C2m13, C2m39 and C2m31 had nonsense mutations that resulted in decreased CST mRNA stability, and C2m34 carried a putative splice site mutation. PSA and CD15s expression in CST-deficient Lec2 cells were partially rescued by G217E CST, but not by G256E CST, although both proteins were expressed at similar levels, and localized to the Golgi. These results indicate that the novel missense mutations isolated in this study affect CST activity.

• Molecules and Cells
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• 제40권6호
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• pp.401-409
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• 2017

The primary cilium is a non-motile microtubule-based organelle that protrudes from the surface of most human cells and works as a cellular antenna to accept extracellular signals. Primary cilia assemble from the basal body during the resting stage ($G_0$ phase) and simultaneously disassemble with cell cycle re-entry. Defective control of assembly or disassembly causes diverse human diseases including ciliopathy and cancer. To identify the effective compounds for studying primary cilium disassembly, we have screened 297 natural compounds and identified 18 and 17 primary cilium assembly and disassembly inhibitors, respectively. Among them, the application of KY-0120, identified as Brefeldin A, disturbed Dvl2-Plk1-mediated cilium disassembly via repression of the interaction of $CK1{\varepsilon}-Dvl2$ and the expression of Plk1 mRNA. Therefore, our study may suggest useful compounds for studying the cellular mechanism of primary cilium disassembly to prevent ciliopathy and cancer.

• 대한바이러스학회지
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• 제30권1호
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• pp.83-99
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• 2000

A defective HIV-1 helper virus DNA, pHyPC, was assembled by deleting the RNA packaging signal, env, nef and the 3'LTR sequences. HIV-1 like virus particles that carry the HIV-1 receptor, CD4 were generated by co expression of pHyPC and plasmid DNAs encoding different chimeric CD4 proteins. The CD4 particles, sharing the CD4 ectodomain, precisely fused to different membrane anchors. CD4(+) particles specifically bound to HIV-1 Env expressing cells, but any signs of infection into these cells were not detected. Binding was only partially blocked by either polyclonal anti-CD4 antibodies or by high concentrations of soluble CD4. Surprisingly, CD4(+) particles also adsorbed to HeLa, CHO, NIH3T3 and COS-7 cells in the absence of HIV-1 Env expression. Adsorption was comparable in strength and speed to the highly specific CD4-Env interaction. CD4(-) particles exhibited only background levels of binding. Cell binding was CD4. dependent, but it was independent of the cell type from which the CD4(+) particles originated. Interestingly, CD4-dependent/Env-independent binding was only found when CD4 was present on virus particles. This suggests that the micro-environment of CD4 on virus particles uniquely expose this new cell binding activity. Its high affinity could explain in part why infection of Env(+) cells by CD4(+) particles was not detected. Further experiments will be required to evaluate whether this strong membrane interaction could represent one step in the multiple-step viral entry process.

• The Korean Journal of Physiology and Pharmacology
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• 제20권4호
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• pp.387-397
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• 2016

Neurofibrillary tangles (NFTs) of microtubule-associated protein tau are a pathological hallmark of Alzheimer's disease (AD). Endoplasmic reticulum (ER) stress has been known to be involved in the pathogenesis of AD. However, the exact role of ER stress in tau pathology has not yet been clearly elucidated. In present study, the possible relationship between tau pathology and ER stress was examined in terms of sorcin, which is a calcium binding protein and plays an important role in calcium homeostasis. Our previous yeast two hybrid study showed that sorcin is a novel tau interacting protein. Caspase-3-cleaved tau (T4C3) showed significantly increased tau-sorcin interaction compared to wild type tau (T4). Thapsigargin-induced ER stress and co-expression of constitutively active $GSK3{\beta}$ ($GSK3{\beta}-S9A$) also exhibited significantly increased tau-sorcin interactions. T4C3-expressing cells showed potentiated thapsigargin -induced apoptosis and disruption of intracellular calcium homeostasis compared to T4-expressing cells. Overexpression of sorcin significantly attenuated thapsigargin-induced apoptosis and disruption of calcium homeostasis. In contrary, siRNA-mediated knock-down of sorcin showed significantly increased thapsigargin-induced apoptosis and disruption of calcium homeostasis. These data strongly suggest that sequestration of sorcin by aberrant forms of tau compromises the function of sorcin, such as calcium homeostasis and cellular resistance by ER stress, which may consequently result in the contribution to the progression of AD.

• 통합자연과학논문집
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• 제4권2호
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• pp.113-120
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• 2011

Brassinosteroids (BRs) are plant steroid hormones that play essential roles in growth and development. Mutations in BR-signaling pathways cause defective in growth and development like dwarfism, male sterility, abnormal vascular development and photomorphogenesis. Transition from vegetative to reproductive growth is a critical phase change in the development of a flowering plant. In a screen of activation-tagged Arabidopsis, we identified a mutant named abz126 that displayed longer hypocotyls when grown in the dark on MS media containing brassinazole (Brz), an inhibitor of BRs biosynthesis. We have cloned the mutant locus using adapter ligation PCR walking and identified that a single T-DNA had been integrated into the ninth exon of the GIGANTEA (GI) gene, involved in controling flowering time. This insertion resulted in loss-of-function of the GI gene and caused the following phenotypes: long petioles, tall plant height, many rosette leaves and late flowering. RT-PCR assays on abz126 mutant showed that the T-DNA insertion in GIGANTEA led to the loss of mRNA expression of the GI gene. In the hormone dose response assay, abz126 mutant showed: 1) an insensitivity to paclobutrazole (PAC), 2) an altered response with 6-benzylaminopurine (BAP) and 3) insensitive to Brassinolide (BL). Based on these results, we propose that the late flowering and tall phenotypes displayed by the abz126 mutant are caused by a loss-of-function of the GI gene associated with brassinosteroid hormone signaling.

• 미생물학회지
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• 제26권4호
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• pp.305-311
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• 1988

Slow growing R. japonicum R-l68 균주로부터 spectinomycin 내성 균주를 선발하고 이 Rhizobium내에 Tn-5를 도입시키기 위하여 Tn5가 함유된 E. coli WA 803/pGS9과의 conjugation을 통한 transposon mutagenesis를 실시하였다. 이때 C conjugation을 통한 Tn5 전이 빈도는 $1.0\times 10^{-5}-5.0\times 10^{-7}$ 범위 이였으며, 얻어진 transconjugant들은 spectinomycin (($100{\mu}$g/ml)과 kanamycin ($50{\mu}$g/ml)을 함유한 yeast extract-mannitol 배지에서 8-10일 배양후 colony를 형성하였다. 또한 transconjugant들은 genome상에 Tn-5를 함유하고 있음을 hybridization-을 통하여 확인하였다. 한편 nodule은 형성 하나 질소고정 활성이 없는 돌연변이주 R. japonicum RMa 75 $nod^{+}fix^{-}$ 균주를 선발하였는데 이 균주는 nodule내에 leghemoglobin이 결핍되어 있음이 확인되었다.