• Title/Summary/Keyword: Transcriptional Activity

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Antioxidant Activity and Its Mechanism of Paeonia lactiflora Pall Extract

  • Heo, Jee-In;Kim, Jeong-Hyeon;Lee, Jeong-Min;Kim, Sung-Chan;Park, Jae-Bong;Kim, Jaebong;Lee, Jae-Yong
    • Natural Product Sciences
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    • v.19 no.1
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    • pp.49-53
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    • 2013
  • Paeonia lactiflora Pall (PL) has been used as a traditional herbal medicine in China, Korea, and Japan for more 1,200 years. PL has reported to have antioxidant activity and protective effect of cells from oxidative stress, although the mechanism has not been verified. FOXO3a is a transcription factor that binds to its target gene's consensus FOXO binding site. FOXO3a protein modulates the various biological functions including cell cycle control, apoptosis, DNA repair, and ROS detoxification. Therefore, FOXO3a activity is associated with cancer, aging, diabetes, infertility, neurodegeneration, and immune system dysfunction. Here we found that FOXO3a was activated by PL extract. Transcriptional target genes such as MnSOD, p27, and GADD45 were activated by PL extract. Protein levels of MnSOD and catalase were increased, consequently, ROS level was reduced in HEF cells by PL extract. These findings suggest that PL extract has an antioxidant activity through FOXO activation and thereby activation of FOXO target genes, MnSOD and catalase.

Role of Disulfide Bond of Arylsulfate Sulfotransferase in the Catalytic Activity

  • Kwon, Ae-Ran;Choi, Eung-Chil
    • Archives of Pharmacal Research
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    • v.28 no.5
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    • pp.561-565
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    • 2005
  • Bacterial arylsulfate sulfotransferase (ASST) catalyzes the transfer of sulfate group from a phenyl sulfate ester to a phenolic acceptor. The promoter region and the transcripti on start sites of Enterobacter amnigenus astA have been determined by primer extension analysis. Northern blot analysis resolved two mRNA species with lengths of 3.3 and 2.0 kb, which correspond to the distances between the transcriptional initiation sites and the two inverted repeat sequences (IRSs). By length, the 3.3 kb RNA could comprise the three-gene (astA with dsbA and dsbB) operon. ASST has three highly conserved cysteine residues. Reducing and non-reducing SDS-PAGE and activity staining showed that disulfide bond is needed for the activity of the enzyme. To identify the cysteine residues responsible for the disulfide bond formation, a series of Cys to Ser mutants has been constructed and the enzymatic activity was measured. Based on the results, we assumed that the first cysteine (Cys349) might be involved in disulfide bond mainly with the second cysteine (Cys445) and result in active conformation.

Molecular Biological Study of Anti-cancer Effects of Bee Venom Aqua-acupuncture (봉독약침(蜂毒藥鍼)의 항암효과(抗癌效果)에 대한 분자생물학적(分子生物學的) 연구(硏究))

  • Park, Chan-Yol;Seo, Jung-Chul;Choi, Do-Young;Ahn, Byoung-Choul
    • Journal of Pharmacopuncture
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    • v.3 no.1
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    • pp.1-19
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    • 2000
  • To study anti-cancer effect and molecular biological mechanism of bee venom for aqua-acupuncture, the effects of bee venom on cell viability and apoptosis were analyzed using MTT assay, tryphan blue assay, $[^3H]$thymidine release assay, flow cytometric analysis, and activity of caspase-3 protease activity assay. To explore whether anti-cancer effects of bee venom are associated with the transcriptional control of gene expression, quantitative RT-PCR analysis of apoptosis-related genes was performed. The obtained results are summarized as follows: 1. The MTT assay demonstrated that cell viability was decreased by bee venom in a dose-dependant manner. 2. Significant induction of apoptosis was identified using tryphan blue assay, $[^3H]$thymidine release assay, and flow cytomet1 ric analysis of sub $G_1$ fraction. 3. In analysis of caspase-3 protease activity, the activity had increased significantly, in a dose-dependant manner. 4. Quantitative RT-PCR analysis of the apoptosis-related genes showed that Bcl-2 and Bcl-$X_L$ were down-regulated whereas Bax was up-regulated by bee venom treatment.

Anti-melanogenic property of ginsenoside Rf from Panax ginseng via inhibition of CREB/MITF pathway in melanocytes and ex vivo human skin

  • Lee, Ha-Ri;Jung, Joon Min;Seo, Ji-Yeon;Chang, Sung Eun;Song, Youngsup
    • Journal of Ginseng Research
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    • v.45 no.5
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    • pp.555-564
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    • 2021
  • Background: Ginsenosides of Panax ginseng are used to enhance skin health and beauty. The present study aimed to investigate the potential use of ginsenoside Rf (Rf) from Panax ginseng as a new anti-pigmentation agent. Methods: The anti-melanogenic effects of Rf were explored. The transcriptional activity of the cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) and the expression levels of tyrosinase, microphthalmia-associated transcription factor (MITF), and tyrosinase-related proteins (Tyrps) were evaluated in melanocytes and UV-irradiated ex vivo human skin. Results: Rf significantly inhibited Forskolin (FSK) or UV-stimulated melanogenesis. Consistently, cellular tyrosinase activity and levels of MITF, tyrosinase, and Tyrps were downregulated. Furthermore, Rf suppressed MITF promoter activity, which was stimulated by FSK or CREB-regulated transcription coactivator 3 (CRTC3) overexpression. Increased CREB phosphorylation and protein kinase A (PKA) activity induced by FSK were also mitigated in the presence of Rf. Conclusion: Rf can be used as a reliable anti-pigmentation agent, which has a scientifically confirmed and reproducible action mechanism, via inhibition of CREB/MITF pathway.

Identification of a Novel Human Zinc Finger Gene, ZNF438, with Transcription Inhibition Activity

  • Zhong, Zhaomin;Wan, Bo;Qiu, Yun;Ni, Jun;Tang, Wenwen;Chen, Xinya;Yang, Yun;Shen, Suqin;Wang, Ying;Bai, Meirong;Lang, Qingyu;Yu, Long
    • BMB Reports
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    • v.40 no.4
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    • pp.517-524
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    • 2007
  • There were many different families of zinc finger proteins that contained multiple cysteine and/or histidine residues and used zinc to stabilize their folds. The classical C2H2 zinc finger proteins were the founding members of this superfamily and were among the most abundant proteins in eukaryotic genomes. C2H2 proteins typically contained several C2H2 fingers that made tandem contacts along the DNA. Here we reported a novel C2H2 type zinc finger gene, ZNF438, which encoded 828 amino acids that formed five zinc finger domains. Bioinformatics analysis revealed that the ZNF438 was mapped to human chromosome 10p11.2 and shared 62% identity with rat and mouse homologues. RT-PCR analysis indicated that it was ubiquitously expressed in 18 human adult tissues. With immunofluorescence assay, it was shown that the exogenous Flag-tagged ZNF438 was located in nucleus of COS-7 cells. To further explore the function of ZNF438, we examined the transcriptional activity of ZNF438 protein by transfecting recombinant pM-ZNF438 into mammalian cells. The subsequent analysis based on the duel luciferase assay system showed that ZNF438 was a transcriptional repressor.

Characterization of the porcine Nanog 5'-flanking region

  • Memon, Azra;Song, Ki-Duk;Lee, Woon Kyu
    • Asian-Australasian Journal of Animal Sciences
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    • v.31 no.3
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    • pp.449-456
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    • 2018
  • Objective: Nanog, a homeodomain protein, has been investigated in humans and mice using embryonic stem cells (ESCs). Because of the limited availability of ESCs, few studies have reported the function and role of Nanog in porcine ESCs. Therefore, in this study, we investigated the location of the porcine Nanog chromosome and its basal promoter activity, which might have potential applications in development of ESCs specific marker as well as understanding its operating systems in the porcine. Methods: To characterize the porcine Nanog promoter, the 5'-flanking region of Nanog was isolated from cells of mini-pig ears. BLAST database search showed that there are two porcine Nanog genomic loci, chromosome 1 and 5, both of which contain an exon with a start codon. Deletion mutants from the 5'-flanking region of both loci were measured using the Dual-Luciferase Reporter Assay System, and a fluorescence marker, green fluorescence protein. Results: Promoter activity was detected in the sequences of chromosome 5, but not in those of chromosome 1. We identified the sequences from -99 to +194 that possessed promoter activity and contained transcription factor binding sites from deletion fragment analysis. Among the transcription factor binding sites, a Sp1 was found to play a crucial role in basal promoter activity, and point mutation of this site abolished its activity, confirming its role in promoter activity. Furthermore, gel shift analysis and chromatin immunoprecipitation analysis confirmed that Sp1 transcription factor binds to the Sp1 binding site in the porcine Nanog promoter. Taken together, these results show that Sp1 transcription factor is an essential element for porcine Nanog basal activity the same as in human and mouse. Conclusion: We showed that the porcine Nanog gene is located on porcine chromosome 5 and its basal transcriptional activity is controlled by Sp1 transcription factor.

Knockdown of GCF2/LRRFIP1 by RNAi Causes Cell Growth Inhibition and Increased Apoptosis in Human Hepatoma HepG2 Cells

  • Li, Jing-Ping;Cao, Nai-Xia;Jiang, Ri-Ting;He, Shao-Jian;Huang, Tian-Ming;Wu, Bo;Chen, De-Feng;Ma, Ping;Chen, Li;Zhou, Su-Fang;Xie, Xiao-Xun;Luo, Guo-Rong
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.6
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    • pp.2753-2758
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    • 2014
  • Background: GC-binding factor 2 (GCF2) is a transcriptional regulator that represses transcriptional activity of the epidermal growth factor receptor (EGFR) by binding to a specific GC-rich sequence in the EGFR gene promoter. In addition to this function, GCF2 has also been identified as a tumor-associated antigen and regarded as a potentially valuable serum biomarker for early human hepatocellular carcinoma (HCC) diagnosis. GCF2 is high expressed in most HCC tissues and cell lines including HepG2. This study focused on the influence of GCF2 on cell proliferation and apoptosis in HepG2 cells. Materials and Methods: GCF2 expression at both mRNA and protein levels in HepG2 cells was detected with reverse transcription (RT) PCR and Western blotting, respectively. RNA interference (RNAi) technology was used to knock down GCF2 mRNA and protein expression. Afterwards, cell viability was analyzed with a Cell Counting Kit-8 (CCK-8), and cell apoptosis and caspase 3 activity by flow cytometry and with a Caspase 3 Activity Kit, respectively. Results: Specific down-regulation of GCF2 expression caused cell growth inhibition, and increased apoptosis and caspase 3 activity in HepG2 cells. Conclusions: These primary results suggest that GCF2 may influence cell proliferation and apoptosis in HepG2 cells, and also provides a molecular basis for further investigation into the possible mechanism at proliferation and apoptosis in HCC.

Mechanism for Antioxidant Activity of Nardostachys chinensis root Extract

  • Heo, Jee-In;Kim, Jeong-Hyeon;Lee, Jeong-Min;Kim, Sung Chan;Park, Jae-Bong;Kim, Jaebong;Lee, Jae-Yong
    • Journal of Applied Biological Chemistry
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    • v.57 no.1
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    • pp.17-22
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    • 2014
  • Nardostachys chinensis (N. chinensis) has been used in traditional medicine as a sedative and analgesic. It has been reported that N. chinensis extract has an antioxidant activity. However, the mechanism has not been elucidated. In this study, we showed that FOXO3a was activated by N. chinensis extract. FOXO3a is a transcriptional factor that involved in cell cycle arrest, DNA repair, apoptosis, and detoxification of reactive oxygen spices (ROS). Protein level of FOXO3a was increased by N. chinensis extract whereas phospho-FOXO3a (Thr 32) was not changed. Promoter activities of target genes of FOXO3a such as MnSOD, p27, and GADD45 were increased by N. chinensis extract. Among target genes, protein level of MnSOD was increased by N. chinensis extract, and this leads to removal of ROS level in human embryonic fibroblast (HEF) cells. These results suggested that N. chinensis extract has an antioxidant activity by upregulation of MnSOD through FOXO3a activation.

Cytochrome P-450 3A4 proximal promoter activity by histone deacetylase inhibitor in HepG2 cell.

  • Kim, Ja-Young;Ahn, Mee-Ryung;Sheen, Yhun-Yhong
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 2003.11a
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    • pp.88-88
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    • 2003
  • Cytochrome P-450 3A4 (CYP3A4) is major enzyme in human liver, the role of this is detoxification and metabolizing more than 50% clinical drugs in use. Expression of CYP3A4 is transciptionally regulated by the Pregnenolone X receptor (PXR), of which human form is Steroid and Xenobiotics receptor (SXR). SXR is activated by wide range of endogenous and exogenous compounds, and then induces CYP3A4 gene expression. In the previous study, it has been known that proximal promoter (-864 to +64) does not response to chemical inducers such as pregnenolone 16a-carbonitrile (PCN), Rifampicin, Estrogen in terms of transcription of CYP 3A4 in cultured cells. Here, we developed luciferase reporter gene assay system to detect SXR-based CYP 3A4 transcriptional activity. We have used CYP3A4-Luc plasmid that contains proximal promoter of human CYP3A4 gene upstream of the luciferase gene. We did transient transfection of 3A4-luciferase gene and SXR. In the HepG2 cells transfected with CYP3A4-Luc, when rifampicin treatment was combined with histone deacetylase inhibitor (HDAC Inhibitor), such as Trichostatin A, Hc-toxin and IN 2001 of the luciferase activity was induced 10-20 fold over control.

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Phospholipase D and Its Essential Role in Cancer

  • Cho, Ju Hwan;Han, Joong-Soo
    • Molecules and Cells
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    • v.40 no.11
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    • pp.805-813
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    • 2017
  • The role of phospholipase D (PLD) in cancer development and management has been a major area of interest for researchers. The purpose of this mini-review is to explore PLD and its distinct role during chemotherapy including anti-apoptotic function. PLD is an enzyme that belongs to the phospholipase super family and is found in a broad range of organisms such as viruses, yeast, bacteria, animals, and plants. The function and activity of PLD are widely dependent on and regulated by neurotransmitters, hormones, small monomeric GTPases, and lipids. A growing body of research has shown that PLD activity is significantly increased in cancer tissues and cells, indicating that it plays a critical role in signal transduction, cell proliferation, and anti-apoptotic processes. In addition, recent studies show that PLD is a downstream transcriptional target of proteins that contribute to inflammation and carcinogenesis such as Sp1, $NF{\kappa}B$, TCF4, ATF-2, NFATc2, and EWS-Fli. Thus, compounds that inhibit expression or activity of PLD in cells can be potentially useful in reducing inflammation and sensitizing resistant cancers during chemotherapy.