• Journal of Microbiology and Biotechnology
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• v.32 no.9
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• pp.1134-1145
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• 2022

SCO6993 (606 amino acids) in Streptomyces coelicolor belongs to the large ATP-binding regulators of the LuxR family regulators having one DNA-binding motif. Our previous findings predicted that SCO6993 may suppress the production of pigmented antibiotics, actinorhodin, and undecylprodigiosin, in S. coelicolor, resulting in the characterization of its properties at the molecular level. SCO6993-disruptant, S. coelicolor ΔSCO6993 produced excess pigments in R2YE plates as early as the third day of culture and showed 9.0-fold and 1.8-fold increased production of actinorhodin and undecylprodigiosin in R2YE broth, respectively, compared with that by the wild strain and S. coelicolor ΔSCO6993/SCO6993⁺. Real-time polymerase chain reaction analysis showed that the transcription of actA and actII-ORF4 in the actinorhodin biosynthetic gene cluster and that of redD and redQ in the undecylprodigiosin biosynthetic gene cluster were significantly increased by SCO6993-disruptant. Electrophoretic mobility shift assay and DNase footprinting analysis confirmed that SCO6993 protein could bind only to the promoters of pathway-specific transcriptional activator genes, actII-ORF4 and redD, and a specific palindromic sequence is essential for SCO6993 binding. Moreover, SCO6993 bound to two palindromic sequences on its promoter region. These results indicate that SCO6993 suppresses the expression of other biosynthetic genes in the cluster by repressing the transcription of actII-ORF4 and redD and consequently negatively regulating antibiotic production.

• Biomolecules & Therapeutics
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• v.18 no.2
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• pp.178-183
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• 2010

Costunolide is an active compound isolated from the stem bark of Magnolia sieboldii, and is considered a potential therapeutic for the treatment of various cancers. In this study, we investigated the underlying mechanism whereby costunolide induces the apoptosis of human leukemia cells. Using apoptosis analysis and quantitative reverse transcription-polymerase chain reaction (RT-PCR) results obtained during this study show that costunolide is a potent inducer of apoptosis and that it is triggered due to the premature activation of Cdc2. $G_1$-synchronized cells, which cannot undergo mitosis, were found to be more sensitive to costunolide, and Cdc2 mRNA levels were increased by costunolide treatment. Furthermore, the Cdk inhibitors, olomucine and butyrolactone I, were found to suppress costunolide-induced apoptosis. In addition, the PKC activator TPA rescued cells from cell death by costunolide, and this was prevented by the PKC inhibitor staurosporin. The present study suggests that costunolide induces the apoptosis of HL-60 leukemic cells by modulating cyclin-dependent kinase Cdc2.

• Journal of Ginseng Research
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• v.39 no.3
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• pp.189-198
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• 2015

Background: Antiallergic effect of 20(S)-protopanaxatriol (PPT), an intestinal metabolite of ginseng saponins, was investigated in guinea pig lung mast cells and mouse bone marrow-derived mast cells activated by a specific antigen/antibody reaction. Methods: Increasing concentrations of PPT were pretreated 5 min prior to antigen stimulation, and various inflammatory mediator releases and their relevant cellular signaling events were measured in those cells. Results: PPT dose-dependently reduced the release of histamine and leukotrienes in both types of mast cells. Especially, in activated bone marrow-derived mast cells, PPT inhibited the expression of Syk protein, cytokine mRNA, cyclooxygenase-1/2, and phospholipase $A_2$ ($PLA_2$), as well as the activities of various protein kinase C isoforms, mitogen-activated protein kinases, $PLA_2$, and transcription factors (nuclear factor-${\kappa}B$ and activator protein-1). Conclusion: PPT reduces the release of inflammatory mediators via inhibiting multiple cellular signaling pathways comprising the $Ca^{2+}$ influx, protein kinase C, and $PLA_2$, which are propagated by Syk activation upon allergic stimulation of mast cells.

• BMB Reports
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• v.49 no.11
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• pp.587-589
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• 2016

The circadian clock system enables organisms to anticipate the rhythmic environmental changes and to manifest behavior and physiology at advantageous times of the day. Transcriptional/translational feedback loop (TTFL) is the basic feature of the eukaryotic circadian clock and is based on the rhythmic association of circadian transcriptional activator and repressor. In Drosophila, repression of dCLOCK/CYCLE (dCLK/CYC) mediated transcription by PERIOD (PER) is critical for inducing circadian rhythms of gene expression. Pacemaker neurons in the brain control specific circadian behaviors upon environmental timing cues such as light and temperature cycle. We show that amino acids 657-707 of dCLK are important for the transcriptional activation and the association with PER both in vitro and in vivo. Flies expressing dCLK lacking AA657-707 in $Clk^{out}$ genetic background, homologous to the mouse Clock allele where exon 19 region is deleted, display pacemaker-neuron-dependent perturbation of the molecular clockwork. The molecular rhythms in light-cycle-sensitive pacemaker neurons such as ventral lateral neurons ($LN_vs$) were significantly disrupted, but those in temperature-cycle-sensitive pacemaker neurons such as dorsal neurons (DNs) were robust. Our results suggest that the dCLK-controlled TTFL diversify in a pacemaker-neuron-dependent manner which may contribute to specific functions such as different sensitivities to entraining cues.

• BMB Reports
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• v.51 no.9
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• pp.425-426
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• 2018

As highly conserved signaling cascades of multicellular organisms, Wnt and Hippo pathways control a wide range of cellular activities, including cell adhesion, fate determination, cell cycle, motility, polarity, and metabolism. Dysregulation of those pathways are implicated in many human diseases, including cancer. Similarly to ${\beta}-catenin$ in the Wnt pathway, the YAP transcription co-activator is a major player in Hippo. Although the intracellular dynamics of YAP are well-known to largely depend on phosphorylation by LATS and AMPK kinases, the molecular effector of YAP cytosolic translocation remains unidentified. Recently, we reported that the Dishevelled (DVL), a key scaffolding protein between canonical and non-canonical Wnt pathway, is responsible for nuclear export of phosphorylated YAP. The DVL is also required for YAP intracellular trafficking induced by E-cadherin, ${\alpha}-catenin$, or metabolic stress. Note that the p53/LATS2 and LKB1/AMPK tumor suppressor axes, commonly inactivated in human cancer, govern the reciprocal inhibition between DVL and YAP. Conversely, loss of the tumor suppressor allows co-activation of YAP and Wnt independent of epithelial polarity or contact inhibition in human cancer. These observations provide novel mechanistic insight into (1) a tight molecular connection merging the Wnt and Hippo pathways, and (2) the importance of tumor suppressor contexts with respect to controlled proliferation and epithelial polarity regulated by cell adhesion.

• BMB Reports
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• v.36 no.1
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• pp.120-127
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• 2003

The formation of new blood vessels, angiogenesis, is an essential process during development and disease. Angiogenesis is well known as a crucial step in tumor growth and progression. Angiogenesis is induced by hypoxic conditions and regulated by the hypoxia-inducible factor 1 (HIF-1). The expression of HIF-1 correlates with hypoxia-induced angiogenesis as a result of the induction of the major HIF-1 target gene, vascular endothelial cell growth factor (VEGF). In this review, a brief overview of the mechanism of angiogenesis is discussed, focusing on the regulatory processes of the HIF-1 transcription factor. HIF-1 consists of a constitutively expressed HIF-1 beta(HIF-1β) subunit and an oxygen-regulated HIF-1 alpha(HIF-1α) subunit. The stability and activity of HIF-1α are regulated by the interaction with various proteins, such as pVHL, p53, and p300/CBP as well as by post-translational modifications, hydroxylation, acetylation, and phosphorylation. It was recently reported that HIF-1α binds a co-activator of the AP-1 transciption factor, Jab-1, which inhibits the p53-dependent degradation of HIF-1 and enhances the transcriptional activity of HIF-1 and the subsequent VEGF expression under hypoxic conditions. ARD1 acetylates HIF-1α and stimulates pVHL-mediated ubiquitination of HIF-1α. With a growing knowledge of the molecular mechanisms in this field, novel strategies to prevent tumor angiogenesis can be developed, and form these, new anticancer therapies may arise.

• BMB Reports
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• v.37 no.3
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• pp.320-334
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• 2004

StMBF1 (Solanum tuberosum multiprotein bridging factor 1) is a plant member of the MBF1 family of transcriptional co-activators. In an attempt to understand the role of StMBF1, we analyzed its interaction with plant transcription factors of the homeodomain-leucine zipper (Hd-Zip) family, a group of proteins with a typical leucine zipper motif adjacent to a homeodomain. StMBF1 is able to interact in vitro with the Hd-Zip protein Hahb-4 both in the presence and absence of DNA. Upon binding, StMBF1 increases the DNA binding affinity of Hahb-4, and of another plant homeodomain containing protein from the GL2/Hd-Zip IV family, HAHR-1. The biological role of interactions is discussed in this paper.

• The Journal of Internal Korean Medicine
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• v.38 no.6
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• pp.1035-1048
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• 2017

Objectives: This study was performed to investigate the effects of Gardenia jasminoides extract (GJ) on osteoclast differentiation and bone resorption in vitro. Methods: To investigate the effect of GJ on osteoclast differentiation, the mouse leukemic myeloid cell line RAW 264.7 was stimulated by RANKL (receptor activator of nuclear factor kB ligand). Osteoclast differentiation was measured by counting TRAP (+) MNC in the presence of RANKL. To elucidate the mechanism of the inhibitory effect of GJ on osteoclast differentiation, gene expression of TRAP, Cathepsin K, MMP-9, NFATc1, c-Fos, MITF, DC-STAMP, CTR, OC-STAMP and Atp6v0d2 was measured using reverse transcription-PCR (RT-PCR). Bone resorption was measured using the bone pit formation assay. Results: GJ decreased the number of TRAP (+) MNCs in the presence of RANKL. GJ inhibited the expression of cathepsin K, MMP-9, TRAP, MITF, NFATc1, c-Fos, iNON, OC-STAMP, Atp6v0d2, and DC-STAMP in the osteoclast, and inhibited bone pit formation in vitro. Conclusions: The results suggest that GJ has inhibitory effects on bone resorption resulting from inhibition of osteoclast differentiation and gene expression.

• Journal of Microbiology and Biotechnology
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• v.19 no.2
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• pp.121-127
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• 2009

Sequencing analysis of a 5-kb DNA fragment from Streptomyces venezuelae ATCC 15439 revealed the presence of one 3.1-kb open reading frame(ORF), designated as afsR-sv. The deduced product of afsR-sv(1,056 aa) was found to have high homology with the global regulatory protein AfsR. Homology-based analysis showed that aftR-sv represents a transcriptional activator belonging to the Streptomyces antibiotic regulatory protein(SARP) family that includes an N-terminal SARP domain containing a bacterial transcriptional activation domain(BTAD), an NB-ARC domain, and a C-terminal tetratricopeptide repeat domain. Gene expression analysis by reverse transcriptase PCR(RT-PCR) demonstrated the activation of transcription of genes belonging to pikromycin production, when aftR-sv was overexpressed in S. venezuelae. Heterologous expression of the aftR-sv in different Streptomyces strains resulted in increased production of the respective antibiotics, suggesting that afsR-sv is a positive regulator of antibiotics biosynthesis.

• Nutrition Research and Practice
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• v.14 no.5
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• pp.453-462
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• 2020

BACKGROUND/OBJECTIVES: Platycodon grandiflorum (PG), an oriental herbal medicine, has been known to improve liver function, and has both anti-inflammatory and antimicrobial properties. However, little is known about the immune-enhancing effects of PG and its mechanism. In this study, we aimed to investigate whether fermented PG extract (FPGE), which has increased platycodin D content, activates the immune response in a murine macrophage cell line, RAW 264.7. MATERIALS/METHODS: Cell viability was determined by Cell Counting Kit-8 assay and the nitric oxide (NO) levels were measured using Griess reagent. Cytokine messenger RNA levels of were monitored by quantitative reverse transcription polymerase chain reaction. To investigate the molecular mechanisms underlying immunomodulatory actions of FPGE in RAW 264.7 cells, we have conducted luciferase reporter gene assay and western blotting. RESULTS: We found that FPGE treatment induced macrophage cell proliferation in a dose-dependent manner. FPGE also modulated the expression of NO and pro-inflammatory cytokines, such as tumor necrosis factor-α, interleukin (IL)-1β, and IL-6. The activation and phosphorylation levels of nuclear factor kappa B (NF-κB) were increased by FPGE treatment. Moreover, 5-aminoimidazole-4-carboxamide ribonucleotide, an activator of AMP-activated kinase (AMPK), significantly reduced both lipopolysaccharides- and FPGE-induced NF-κB reporter gene activity. CONCLUSIONS: Taken together, our findings suggest that FPGE may be a novel immune-enhancing agent acting via AMPK-NF-κB signaling pathway.