• Title/Summary/Keyword: positive regulator

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Cation Flux-Mediated Activation of P-Type ATPase in Helicobacter pylori

  • Yun, Soon-Kyu;Ki, Mi-Ran;Park, Jeong-Kyu;Lim, Wang-Jin;Hwang, Se-Young
    • Journal of Microbiology and Biotechnology
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    • v.10 no.4
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    • pp.441-448
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    • 2000
  • The production and cation flux-mediated activation of the P-type ATPase in Helicobacter pylori was investigated. Using the polymerase chain reaction (PCR), the proton pump genotype of H. pylori was found to be positive for both F-type and P-type ATPases. Yet, their production in terms of enzyme specific activity varied substantially depending on H. pylori strains, ranging over 3-fold. Its main constituent appeared to be the P-type ATPase pool, in contrast to other common bacterial compositions. Interestingly, the F-type ATPase was observed only when intact H. pyloricells were exposed to pH 4.5 or above (37$^{\circ}C$ for 1 h). In contrast, significant amounts of the P-type ATPase still remained after 1 h of cell treatment even at pH below 4.5. By enriching the acidic medium with RPMI(pH 3.0), the P-type ATPase was stabilized, accompained by inactivation of the F-type ATPase. Using H. pylori membrane vesicles, it was found that ammionia-mediated cation flux increased the rate of ATP hydrolysis by the P-type ATPase. Accordingly, these data strongly suggest that the P-type ATPase is involved or functions as an effective regulator for the cation flux across the H. pylori membrane, thereby reducing the risk of excess proton influx.

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Identification and Functional Characterization of an afsR Homolog Regulatory Gene from Streptomyces venezuelae ATCC 15439

  • Maharjan, Sushila;Oh, Tae-Jin;Lee, Hei-Chan;Sohng, Jae-Kyung
    • 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.

Lentivirus-mediated Silencing of Rhomboid Domain Containing 1 Suppresses Tumor Growth and Induces Apoptosis in Hepatoma HepG2 Cells

  • Liu, Xue-Ni;Tang, Zheng-Hao;Zhang, Yi;Pan, Qing-Chun;Chen, Xiao-Hua;Yu, Yong-Sheng;Zang, Guo-Qing
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.1
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    • pp.5-9
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    • 2013
  • Rhomboids were identified as the first intramembrane serine proteases about 10 years ago. Since then, the study of the rhomboid protease family has blossomed. Rhomboid domain containing 1 (RHBDD1), highly-expressed in human testis, contains a rhomboid domain with unknown function. In the present study, we tested the hypothesis that RHBDD1 was associated with proliferation and apoptosis in hepatocellular carcinoma using recombinant lentivirus-mediated silencing of RHBDD1 in HepG2 cells. Our results showed that down-regulation of RHBDD1 mRNA levels markedly suppressed proliferation and colony formation capacity of HepG2 human hepatoma cancer cells in vitro, and induced cell cycle arrest. We also found that RHBDD1 silencing could obviously trigger HepG2 cell apoptosis. In summary, it was demonstrated that RHBDD1 might be a positive regulator for proliferative and apoptotic characteristics of hepatocellular carcinoma.

Tusc2/Fus1 regulates osteoclast differentiation through NF-κB and NFATc1

  • Kim, Inyoung;Kim, Jung Ha;Kim, Kabsun;Seong, Semun;Kim, Nacksung
    • BMB Reports
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    • v.50 no.9
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    • pp.454-459
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    • 2017
  • Tumor suppressor candidate 2 (Tusc2, also known as Fus1) regulates calcium signaling, and $Ca^{2+}$-dependent nuclear factor of activated T-cells (NFAT) and nuclear factor kappa B ($NF-{\kappa}B$) pathways, which play roles in osteoclast differentiation. However, the role of Tusc2 in osteoclasts remains unknown. Here, we report that Tusc2 positively regulates the differentiation of osteoclasts. Overexpression of Tusc2 in osteoclast precursor cells enhanced receptor activator of nuclear factor ${\kappa}B$ ligand (RANKL)-induced osteoclast differentiation. In contrast, small interfering RNA-mediated knockdown of Tusc2 strongly inhibited osteoclast differentiation. In addition, Tusc2 induced the activation of RANKL-mediated $NF-{\kappa}B$ and calcium/calmodulin-dependent kinase IV (CaMKIV)/cAMP-response element (CRE)-binding protein CREB signaling cascades. Taken together, these results suggest that Tusc2 acts as a positive regulator of RANKL-mediated osteoclast differentiation.

Tunicamycin negatively regulates BMP2-induced osteoblast differentiation through CREBH expression in MC3T3E1 cells

  • Jang, Won-Gu;Kim, Eun-Jung;Koh, Jeong-Tae
    • BMB Reports
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    • v.44 no.11
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    • pp.735-740
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    • 2011
  • Tunicamycin, an endoplasmic reticulum (ER) stress inducer, specifically inhibits N-glycosylation. The cyclic AMP (cAMP) response element-binding protein H (CREBH) was previously shown to be regulated by UPR-dependent proteolytic cleavage in the liver. On the other hand, the role of CREBH in other tissues is unknown. In the present study, tunicamycin increased the level of CREBH activation (cleavage) as well as mRNA expression in osteoblast cells. Adenoviral (Ad) overexpression of CREBH suppressed BMP2-induced expression of alkaline phosphatase (ALP) and osteocalcin (OC). Interestingly, the BMP2-induced OASIS (structurally similar to CREBH, a positive regulator of osteoblast differentiation) expression was also inhibited by CREBH overexpression. In addition, inhibition of CREBH expression using siRNA reversed the tunicamycin-suppressed ALP and OC expression. These results suggest that CREBH inhibited osteoblast differentiation via suppressing BMP2-induced ALP, OC and OASIS expression in mouse calvarial derived osteoblasts.

Promotion of Asexual Development and Inhibition of Sexual Development of Aspergillus nidulans by Short-Chain Primary Amines

  • Song, Myung-Hoon;Kuppusamy Selvam;Park, Chang-Jun;Jahng, Kwang-Yeop;Han, Dong-Min;Chae, Keon-Sang
    • Journal of Microbiology
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    • v.40 no.3
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    • pp.230-233
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    • 2002
  • Effects of short-chain primary amines on Aspergillus nidulans development were analyzed. Propylamine induced asexual development and inhibited sexual development. Even on medium containing lactose as the sole carbon source, on which little conidial heads are formed and sexual structures are formed preferentially, or when sexual development was induced, propylamine induced asexual development and inhibited sexual development. These effects of propylamine seemed to be due to accumulation of mRNA of the brlA gene, which has been identified as a positive regulator of asexual development, and due to the reduction of the veA mRNA level. The veA gene has been identified as an activator of sexual development and also as an inhibitor of asexual development. Other primary amines, methylamine and ethylamine, showed identical effects on development where short-chain primary amino also promoted asexual development and inhibited sexual development.

The Effect of Jazf1 Overexpression in Zebrafish Cardiac Development

  • Shin, Mi-Jung;Yuh, Hyung-Soo;Seo, Byoung-Boo;Park, Hum-Dai;Yoon, Du-Hak;Ryoo, Zae-Young
    • Reproductive and Developmental Biology
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    • v.35 no.4
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    • pp.457-461
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    • 2011
  • JAZF1 (Juxtaposed with Another Zinc Finger gene 1) transcription factor are Zn-finger proteins that bind to the nuclear orphan receptor TAK/TR4 (Nakajima et al., 2004). The nuclear orphan receptor TAK1/TR4 functions as a positive as well as a negative regulator of transcription. It was recently reported that congenital cardiovascular malformations are significantly more frequent in Neurofibromatosis 1 (NF1) patients with microdeletion syndrome than in those with classical NF1. JAZF1 was expressed in adult heart of patients with microdeletion syndrome. JAZF1 is highly conserved among various species include zebrafish. We hypothesized that the expression of zebrafish Jazf1 may lead to severe forms of congenital heart disease that allow the survival of newborns and adults. In this study, we created Jazf1 transgenic zebrafish which over-express zebrafish Jazf1 cDNA under control of the CMV promoter. Our results suggested that Jazf1 expression may play an important role in zebrafish cardiac development.

Regulation of DREAM Expression by Group I mGluR

  • Lee, Jin-U;Kim, In-Sook;Oh, So-Ra;Ko, Suk-Jin;Lim, Mi-Kyung;Kim, Dong-Goo;Kim, Chul-Hoon
    • The Korean Journal of Physiology and Pharmacology
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    • v.15 no.2
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    • pp.95-100
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    • 2011
  • DREAM (downstream regulatory element antagonistic modulator) is a calcium-binding protein that regulates dynorphin expression, promotes potassium channel surface expression, and enhances presenilin processing in an expression level-dependent manner. However, no molecular mechanism has yet explained how protein levels of DREAM are regulated. Here we identified group I mGluR (mGluR1/5) as a positive regulator of DREAM protein expression. Overexpression of mGluR1/5 increased the cellular level of DREAM. Up-regulation of DREAM resulted in increased DREAM protein in both the nucleus and cytoplasm, where the protein acts as a transcriptional repressor and a modulator of its interacting proteins, respectively. DHPG (3,5-dihydroxyphenylglycine), a group I mGluR agonist, also up-regulated DREAM expression in cortical neurons. These results suggest that group I mGluR is the first identified receptor that may regulate DREAM activity in neurons.

Estrogen Receptor α Regulates Dlx3-Mediated Osteoblast Differentiation

  • Lee, Sung Ho;Oh, Kyo-Nyeo;Han, Younho;Choi, You Hee;Lee, Kwang-Youl
    • Molecules and Cells
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    • v.39 no.2
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    • pp.156-162
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    • 2016
  • Estrogen receptor ${\alpha}$ (ER-${\alpha}$), which is involved in bone metabolism and breast cancer, has been shown to have transcriptional targets. Dlx3 is essential for the skeletal development and plays an important role in osteoblast differentiation. Various osteogenic stimulators and transcription factors can induce the protein expression of Dlx3. However, the regulatory function of ER-${\alpha}$ in the Dlx3 mediated osteogenic process remains unknown. Therefore, we investigated the regulation of Dlx3 and found that ER-${\alpha}$ is a positive regulator of Dlx3 transcription in BMP2-induced osteoblast differentiation. We also found that ER-${\alpha}$ interacts with Dlx3 and increases its transcriptional activity and DNA binding affinity. Furthermore, we demonstrated that the regulation of Dlx3 activity by ER-${\alpha}$ is independent of the ligand (estradiol) binding domain. These results indicate that Dlx3 is a novel target of ER-${\alpha}$, and that ER-${\alpha}$ regulates the osteoblast differentiation through modulation of Dlx3 expression and/or interaction with Dlx3.

Lonicera Japonica Inhibits Atopy Dermatitis in NC/Nga Mouse through Regulation of iNOS by NF-${\kappa}B$ Suppression (금은화의 NF-${\kappa}B$ 활성 억제를 통한 iNOS 조절이 NC/Nga 생쥐의 아토피 피부염에 미치는 영향)

  • Ahn, Sang-Hyun;Kim, Ho-Hyun
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.24 no.2
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    • pp.278-283
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    • 2010
  • Inducible nitric oxide synthase (iNOS) are important inflammation enzyme and severe up-nitric oxide (NO) production by this enzyme has been intricate with pathogenesis of atopy dermatitis. The present study was designed in order to determine whether Lonicera japonica could inhibit atopy dermatitis through modulation of iNOS by NF-${\kappa}B$ suppression. We found that IKK mRNA and iNOS mRNA expression in RAW 264.7 macrophages stimulated with lipopolysaccharide dose-dependantly decreased by Lonicera japonica (0.4 - 1.0 mg/$m{\ell}$) and NO production decreased. The distribution of NF-${\kappa}B$ p65 and iNOS positive reacted cell in NC/Nga mice with atopy dermatitis were decreased by Lonicera japonica (45 mg/kg/day) and apoptosis were increased. These data likely indicate that Lonicera japonica may act as inflammatory regulator for atopy dermatitis through iNOS modulation by NF-${\kappa}B$B suppression and may be possible to develop useful agent for chemoprevention of NO intricate inflammatory diseases.