1
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Functional characterization of promoter region polymorphisms of human CYP2C19 gene. Mol Biol Rep 2010; 38:4171-9. [DOI: 10.1007/s11033-010-0537-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Accepted: 11/15/2010] [Indexed: 10/18/2022]
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2
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Xu H, He JH, Xiao ZD, Zhang QQ, Chen YQ, Zhou H, Qu LH. Liver-enriched transcription factors regulate microRNA-122 that targets CUTL1 during liver development. Hepatology 2010; 52:1431-42. [PMID: 20842632 DOI: 10.1002/hep.23818] [Citation(s) in RCA: 217] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
UNLABELLED MicroRNA-122 (miR-122) is a liver-specific microRNA whose expression is specifically turned on in the mouse liver during embryogenesis, thus it is expected to be involved in liver development. However, the role of miR-122 in liver development and its potential underlying mechanism remain unclear. Here, we show that the expression of miR-122 is closely correlated with four liver-enriched transcription factors (LETFs)-hepatocyte nuclear factor (HNF) 1α, HNF3β, HNF4α, and CCAAT/enhancer-binding protein (C/EBP) α-in the livers of developing mouse embryos and in human hepatocellular carcinoma (HCC) cell lines. Correspondingly, promoter analysis revealed that these LETFs are coordinately involved in the transcriptional regulation of miR-122, and three HNFs directly bind to the miR-122 promoter as transcriptional activators. Using a luciferase reporter system, we identified a group of miR-122 targets involved in proliferation and differentiation regulation. Among these targets, the most prominently repressed target was CUTL1, a transcriptional repressor of genes specifying terminal differentiation in multiple cell lineages, including hepatocytes. We show that CUTL1 expression is gradually silenced at the posttranscriptional level during mouse liver development. Overexpression and knockdown studies both showed that miR-122 repressed CUTL1 protein expression in HCC cell lines. Finally, we show that the stable restoration of miR-122 in HepG2 cells suppresses cellular proliferation and activates the expression of three hepatocyte functional genes, including the cholesterol-7α hydroxylase gene (CYP7A1), a known target of CUTL1 in hepatocytes. CONCLUSION Our study provides a model in which miR-122 functions as an effector of LETFs and contributes to liver development by regulating the balance between proliferation and differentiation of hepatocytes, at least by targeting CUTL1.
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Affiliation(s)
- Hui Xu
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-Sen University, Guangzhou, People's Republic of China
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3
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Satyanarayana CRU, Devendran A, Jayaraman M, Mannu J, Mathur PP, Gopal SD, Rajagopal K, Chandrasekaran A. Influence of the genetic polymorphisms in the 5' flanking and exonic regions of CYP2C19 on proguanil oxidation. Drug Metab Pharmacokinet 2010; 24:537-48. [PMID: 20045989 DOI: 10.2133/dmpk.24.537] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
CYP2C19 is a polymorphic enzyme which metabolizes several clinically important drugs including proguanil. Variation in the 5' regulatory region may influence CYP2C19 activity. This study evaluates the relationship between proguanil metabolic ratio and genetic variations of CYP2C19 in a South Indian population. Fifty unrelated healthy subjects were genotyped for CYP2C19 (*)2 and (*)3 alleles and the 5' flanking region of CYP2C19 was sequenced. Plasma concentrations of proguanil and cycloguanil were estimated by reverse phase HPLC after single oral doses (200 mg) of proguanil. In silico docking analysis of transcription factors binding to its sites in CYP2C19 5' regulatory region was performed. The mean metabolic ratios (proguanil/cycloguanil) were highest in (*)1/(*)2 or (*)1/(*)3 subjects and in (*)2/(*)2 or (*)2/(*)3 as compared to (*)1/(*)1 subjects. Subjects with promoter region variation -98T>C showed decrease in the metabolic ratios irrespective of other variation, which may explain the deviation from the genotype-phenotype association of CYP2C19. In silico analysis predicted alteration in the interaction of transcription factors to their binding sites in the presence of variant alleles. The results of this study would be useful in predicting interindividual differences in the metabolism of substrates of CYP2C19.
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4
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Wallerman O, Motallebipour M, Enroth S, Patra K, Bysani MSR, Komorowski J, Wadelius C. Molecular interactions between HNF4a, FOXA2 and GABP identified at regulatory DNA elements through ChIP-sequencing. Nucleic Acids Res 2010; 37:7498-508. [PMID: 19822575 PMCID: PMC2794179 DOI: 10.1093/nar/gkp823] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Gene expression is regulated by combinations of transcription factors, which can be mapped to regulatory elements on a genome-wide scale using ChIP experiments. In a previous ChIP-chip study of USF1 and USF2 we found evidence also of binding of GABP, FOXA2 and HNF4a within the enriched regions. Here, we have applied ChIP-seq for these transcription factors and identified 3064 peaks of enrichment for GABP, 7266 for FOXA2 and 18783 for HNF4a. Distal elements with USF2 signal was frequently bound also by HNF4a and FOXA2. GABP peaks were found at transcription start sites, whereas 94% of FOXA2 and 90% of HNF4a peaks were located at other positions. We developed a method to accurately define TFBS within peaks, and found the predicted sites to have an elevated conservation level compared to peak centers; however the majority of bindings were not evolutionary conserved. An interaction between HNF4a and GABP was seen at TSS, with one-third of the HNF4a positive promoters being bound also by GABP, and this interaction was verified by co-immunoprecipitations.
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Affiliation(s)
- Ola Wallerman
- Department of Genetics and Pathology, Rudbeck Laboratory, SE-751 85 Uppsala, Sweden
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5
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Ueda Y, Su Y, Richmond A. CCAAT displacement protein regulates nuclear factor-kappa beta-mediated chemokine transcription in melanoma cells. Melanoma Res 2007; 17:91-103. [PMID: 17496784 PMCID: PMC2665270 DOI: 10.1097/cmr.0b013e3280a60888] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Members of the nuclear factor-kappa beta (NF-kappaB) family maintain cellular homeostasis by enhancing the transcription of genes involved in inflammation, immune response, cell proliferation, and apoptosis. Melanoma tumor cells often express inflammatory mediators through enhanced activation of NF-kappaB. The NF-kappaB activation appears to result from the enhancer formation including NF-kappaB and lysine acetyl transferases such as p300, CREB (cyclic AMP-responsive element binding protein)-binding protein (CBP), and/or p300/CBP associating factor (PCAF). We observed that proteins expressed by Hs294T metastatic melanoma cells are highly acetylated compared with normal melanocytes, and dominant-negative PCAF reduced the basal and tumor necrosis factor-alpha-stimulated transcriptional activity of NF-kappaB. The promoter activity of NF-kappaB-regulated chemokines was also reduced by the expression of dominant-negative PCAF. The promoters of these chemokines contain a CCAAT displacement protein (CDP)-binding site near the NF-kappaB element. compared with vector-transduced cells, in CDP-transduced Hs294T cells: (i) over-expressed CDP bound efficiently to PCAF, (ii) tumor necrosis factor-alpha-stimulated chemokine expression and NF-kappaB-mediated transcription were reduced, and (iii) the binding of CBP to Rel A was reduced. These data suggest that CDP inhibits cytokine-induced NF-kappaB-regulated chemokine transcription. This study contributes to our understanding of the role of CDP in an enhanceosome of NF-kappaB-mediated chemokine transcription in human melanoma cells.
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Affiliation(s)
- Yukiko Ueda
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Yingjun Su
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Ann Richmond
- Department of Veterans Affairs, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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6
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Staloch LJ, Divine JK, Witten JT, Simon TC. C/EBP and Cdx family factors regulate liver fatty acid binding protein transgene expression in the small intestinal epithelium. ACTA ACUST UNITED AC 2005; 1731:168-78. [PMID: 16321657 DOI: 10.1016/j.bbaexp.2005.08.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Revised: 08/09/2005] [Accepted: 08/25/2005] [Indexed: 11/23/2022]
Abstract
A transgene constructed from the rat liver fatty acid binding protein gene (Fabp1) promoter is active in all murine small intestinal crypt and villus epithelial cells. Coincident Cdx and C/EBP transcription factor binding sites were identified spanning Fabp1 nucleotides -90 to -78. CDX-1, CDX-2, C/EBPalpha, and C/EBPbeta activated the Fabp1 transgene in CaCo-2 cells, and mutagenizing the -78 site prevented activation by these factors. CDX but not C/EBP factors bound to the site in vitro, although C/EBP factors competed with CDX factors for transgene activation. The -78 site adjoins an HNF-1 site, and CDX and C/EBP family factors cooperated with HNF-1alpha but not HNF-1beta to activate the transgene. Furthermore, CDX-1, CDX-2, C/EBPalpha, and C/EBPbeta bound to HNF-1alpha and HNF-1beta. The transgene with a mutagenized -78 site was silenced in vivo specifically in small intestinal crypt epithelial cells but remained active in villus cells. These results demonstrate functional interactions between HNF-1, C/EBP, and CDX family factors and suggest that these interactions may contribute to differential transcriptional regulation in the small intestinal crypt and villus compartments.
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Affiliation(s)
- Lora J Staloch
- Department of Pediatrics, Washington University School of Medicine, Campus Box 8208, St. Louis, MO 63110, USA
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7
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Schrem H, Klempnauer J, Borlak J. Liver-enriched transcription factors in liver function and development. Part II: the C/EBPs and D site-binding protein in cell cycle control, carcinogenesis, circadian gene regulation, liver regeneration, apoptosis, and liver-specific gene regulation. Pharmacol Rev 2004; 56:291-330. [PMID: 15169930 DOI: 10.1124/pr.56.2.5] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In the first part of our review (see Pharmacol Rev 2002;54:129-158), we discussed the basic principles of gene transcription and the complex interactions within the network of hepatocyte nuclear factors, coactivators, ligands, and corepressors in targeted liver-specific gene expression. Now we summarize the role of basic region/leucine zipper protein family members and particularly the albumin D site-binding protein (DBP) and the CAAT/enhancer-binding proteins (C/EBPs) for their importance in liver-specific gene expression and their role in liver function and development. Specifically, regulatory networks and molecular interactions were examined in detail, and the experimental findings summarized in this review point to pivotal roles of DBP and C/EBPs in cell cycle control, carcinogenesis, circadian gene regulation, liver regeneration, apoptosis, and liver-specific gene regulation. These regulatory proteins are therefore of great importance in liver physiology, liver disease, and liver development. Furthermore, interpretation of the vast data generated by novel genomic platform technologies requires a thorough understanding of regulatory networks and particularly the hierarchies that govern transcription and translation of proteins as well as intracellular protein modifications. Thus, this review aims to stimulate discussions on directions of future research and particularly the identification of molecular targets for pharmacological intervention of liver disease.
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Affiliation(s)
- Harald Schrem
- Center for Drug Research and Medical Biotechnology, Fraunhofer Institut für Toxikologie und Experimentelle Medizin, Nicolai Fuchs Str. 1, 30625 Hannover, Germany
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8
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Kanaya E, Shiraki T, Jingami H. The nuclear bile acid receptor FXR is activated by PGC-1alpha in a ligand-dependent manner. Biochem J 2004; 382:913-21. [PMID: 15202934 PMCID: PMC1133967 DOI: 10.1042/bj20040432] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2004] [Revised: 06/03/2004] [Accepted: 06/17/2004] [Indexed: 11/17/2022]
Abstract
The nuclear bile acid receptor FXR (farnesoid X receptor) is one of the key factors that suppress bile acid biosynthesis in the liver. PGC-1alpha [PPARgamma (peroxisome-proliferator-activated receptor gamma) co-activator-1alpha] is known to control energy homoeostasis in adipose tissue, skeletal muscle and liver. We performed cell-based reporter assays using the expression system of a GAL4-FXR chimaera, the ligand-binding domain of FXR fused to the DNA-binding domain of yeast GAL4, to find the co-activators for FXR. We found that the transcriptional activation of a reporter plasmid by a GAL4-FXR chimaera was strongly enhanced by PGC-1alpha, in a ligand-dependent manner. Transcriptional activation of the SHP (small heterodimer partner) gene by the FXR-RXRalpha (retinoid X receptor alpha) heterodimer was also enhanced by PGC-1alpha in the presence of CDCA (chenodeoxycholic acid). Co-immunoprecipitation and pull-down studies using glutathione S-transferase-PGC-1alpha fusion proteins revealed that the ligand-binding domain of FXR binds PGC-1alpha in a ligand-influenced manner both in vivo and in vitro. Furthermore, our studies revealed that SHP represses its own transcription, and the addition of excess amounts of PGC-1alpha can overcome the inhibitory effect of SHP. These observations indicate that PGC-1alpha mediates the ligand-dependent activation of FXR and transcription of SHP gene.
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Key Words
- bile acid
- farnesoid x receptor (fxr)
- fasting
- nuclear receptor
- peroxisome-proliferator-activated receptor-γ co-activator-1α (pgc-1α)
- transcriptional co-activator
- cdca, chenodeoxycholic acid
- cyp7a1, cholesterol 7α-hydroxylase
- dbd, dna-binding domain
- dca, deoxycholic acid
- dmem, dulbecco's modified eagle's medium
- eyfp, enhanced yellow fluorescent protein
- fcs, foetal calf serum
- fxr, farnesoid x receptor
- gst, glutathione s-transferase
- hnf-4α, hepatocyte nuclear factor 4α
- hrp, horseradish peroxidase
- lbd, ligand-binding domain
- lca, lithocholic acid
- lrh-1, liver receptor homologue-1
- pepck, phosphoenolpyruvate carboxykinase
- pgc-1α, peroxisome-proliferator-activated receptor γ co-activator-1α
- pparγ, peroxisome-proliferator-activated receptor γ
- rxrα, retinoid x receptor α
- shp, small heterodimer partner
- src1, steroid receptor co-activator 1
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Affiliation(s)
- Eiko Kanaya
- Department of Molecular Biology, Biomolecular Engineering Research Institute (BERI), 6-2-3 Furuedai, Suita-City, Osaka 565-0874, Japan
| | - Takuma Shiraki
- Department of Molecular Biology, Biomolecular Engineering Research Institute (BERI), 6-2-3 Furuedai, Suita-City, Osaka 565-0874, Japan
| | - Hisato Jingami
- Department of Molecular Biology, Biomolecular Engineering Research Institute (BERI), 6-2-3 Furuedai, Suita-City, Osaka 565-0874, Japan
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9
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Hilgard P, Czaja MJ, Gerken G, Stockert RJ. Proapoptotic function of protein kinase CK2alpha" is mediated by a JNK signaling cascade. Am J Physiol Gastrointest Liver Physiol 2004; 287:G192-201. [PMID: 14962846 DOI: 10.1152/ajpgi.00507.2003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Protein kinase CK2 (formerly casein kinase II) is a tetrameric enzyme constitutively expressed in all eurakyotic tissues that plays a significant role in the regulation of cell proliferation, malignant transformation, and apoptosis. The catalytic alpha-subunit of the enzyme is known to exist in three isoforms CK2alpha, CK2alpha' and CK2alpha". CK2alpha" is highly expressed in liver compared with other tissues and is required for the normal trafficking of several hepatocellular membrane proteins. Initial studies of dengue virus infection indicated that the CK2alpha"-deficient membrane trafficking mutant cell line (Trf1) was resistant to virus-induced cell death compared with the parental human hepatoma (HuH)-7 hepatoma line. Expression of recombinant CK2alpha" in Trf1 was capable of reverting this resistant phenotype. This study was extended to TNF-alpha in addition to other stimuli of cell death in an attempt to uncover common death pathways that might be modulated by CK2alpha". Evaluation of different pathways involved in death signaling suggest that the regulation of a critical proapoptotic step in HuH-7 cells by CK2alpha" is mediated by a JNK signaling cascade.
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Affiliation(s)
- Philip Hilgard
- Department for Gastroenterology and Hepatology, University-Hospital Essen, 45133 Essen, Germany
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10
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Rudd S, Frisch M, Grote K, Meyers BC, Mayer K, Werner T. Genome-wide in silico mapping of scaffold/matrix attachment regions in Arabidopsis suggests correlation of intragenic scaffold/matrix attachment regions with gene expression. PLANT PHYSIOLOGY 2004; 135:715-22. [PMID: 15208419 PMCID: PMC514109 DOI: 10.1104/pp.103.037861] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Revised: 03/26/2004] [Accepted: 03/28/2004] [Indexed: 05/17/2023]
Abstract
We carried out a genome-wide prediction of scaffold/matrix attachment regions (S/MARs) in Arabidopsis. Results indicate no uneven distribution on the chromosomal level but a clear underrepresentation of S/MARs inside genes. In cases where S/MARs were predicted within genes, these intragenic S/MARs were preferentially located within the 5'-half, most prominently within introns 1 and 2. Using Arabidopsis whole-genome expression data generated by the massively parallel signature sequencing methodology, we found a negative correlation between S/MAR-containing genes and transcriptional abundance. Expressed sequence tag data correlated the same way with S/MAR-containing genes. Thus, intragenic S/MARs show a negative correlation with transcription level. For various genes it has been shown experimentally that S/MARs can function as transcriptional regulators and that they have an implication in stabilizing expression levels within transgenic plants. On the basis of a genome-wide in silico S/MAR analysis, we found a significant correlation between the presence of intragenic S/MARs and transcriptional down-regulation.
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Affiliation(s)
- Stephen Rudd
- Munich Information Center for Protein Sequences/Institute for Bioinformatics, GSF-National Research Center for Environment and Health, 85764 Neuherberg, Germany
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11
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Rankin EB, Xu W, Silberg DG, Suh E. Putative intestine-specific enhancers located in 5' sequence of the CDX1 gene regulate CDX1 expression in the intestine. Am J Physiol Gastrointest Liver Physiol 2004; 286:G872-80. [PMID: 14715525 DOI: 10.1152/ajpgi.00326.2003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
CDX1 is a homeobox transcription factor that plays a critical role in intestinal epithelial cell growth and differentiation. CDX1 gene expression is tightly regulated in a temporal and cell-type specific manner. However, very little is known about the regulatory mechanisms that direct CDX1 gene expression in the intestine. To elucidate these mechanisms, we employed a series of transgenic mouse studies using the 5' flanking sequences of the human CDX1 gene. Transgenic mice containing nucleotides between -5667 and +68 relative to the transcription start site of the CDX1 gene demonstrated ectopic expression of the transgene in the brain and gastric smooth muscle. However, transgenic expression of the nucleotides -15601 to +68 of the CDX1 gene was restricted to the intestinal epithelium, which was identical to endogenous CDX1 gene expression. Taken together, the upstream sequences between -15601 and -5667 contain regulatory elements that direct transgene expression specifically to the intestinal epithelium. Furthermore, DNase I hypersensitivity assays revealed two active chromatin regions in the CDX1 gene (hypertensive sites 1 and 2) located at approximately -5.8 and -6.8 kb upstream of the CDX1 gene, respectively, which may function as potential intestine-specific enhancers.
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Affiliation(s)
- Erinn B Rankin
- Gastroenterology Div., Dept. of Medicine, Univ. of Pennsylvania, Ste. 600, 415 Curie Blvd., Philadelphia, PA 19104, USA
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12
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Hansmannel F, Clémencet MC, Le Jossic-Corcos C, Osumi T, Latruffe N, Nicolas-Francés V. Functional characterization of a peroxisome proliferator response-element located in the intron 3 of rat peroxisomal thiolase B gene. Biochem Biophys Res Commun 2003; 311:149-55. [PMID: 14575706 DOI: 10.1016/j.bbrc.2003.09.185] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Expression of the rat peroxisomal 3-ketoacyl-CoA thiolase gene B is induced by peroxisome proliferators. Although a sequence element like a peroxisome proliferator-activated receptor (PPAR)-binding site is located in the promoter region of this gene, we previously found that this element is competent for the activation by hepatocyte nuclear factor-4, but not functional with PPARalpha. We describe here a new peroxisome proliferator-response element located in the intron 3 (+1422/+1434) that binds in vitro the PPARalpha/retinoid X receptor alpha heterodimer and confers the induction by PPARalpha in transfection assays. We propose a model of regulation of the rat thiolase B gene involving those elements in the promoter and intron 3.
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13
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Holt JA, Luo G, Billin AN, Bisi J, McNeill YY, Kozarsky KF, Donahee M, Wang DY, Mansfield TA, Kliewer SA, Goodwin B, Jones SA. Definition of a novel growth factor-dependent signal cascade for the suppression of bile acid biosynthesis. Genes Dev 2003; 17:1581-91. [PMID: 12815072 PMCID: PMC196131 DOI: 10.1101/gad.1083503] [Citation(s) in RCA: 524] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The nuclear bile acid receptor FXR has been proposed to play a central role in the feedback repression of the gene encoding cholesterol 7 alpha-hydroxylase (CYP7A1), the first and rate-limiting step in the biosynthesis of bile acids. We demonstrate that FXR directly regulates expression of fibroblast growth factor-19 (FGF-19), a secreted growth factor that signals through the FGFR4 cell-surface receptor tyrosine kinase. In turn, FGF-19 strongly suppresses expression of CYP7A1 in primary cultures of human hepatocytes and mouse liver through a c-Jun N-terminal kinase (JNK)-dependent pathway. This signaling cascade defines a novel mechanism for feedback repression of bile acid biosynthesis and underscores the vital role of FXR in the regulation of multiple pathways of cholesterol catabolism in the liver.
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Affiliation(s)
- Jason A Holt
- Nuclear Receptor Discovery Research, High Throughput Biology, Gene Interference, Transgenics, GlaxoSmithKline, Research Triangle Park, North Carolina 27709, USA
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14
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Amiri KI, Richmond A. Fine tuning the transcriptional regulation of the CXCL1 chemokine. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2003; 74:1-36. [PMID: 14510072 PMCID: PMC3140403 DOI: 10.1016/s0079-6603(03)01009-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Constitutive activation of the transcription factor nuclear factor-κB (NF-κB) plays a major role in inflammatory diseases as well as cancer by inducing the endogenous expression of many proinflammatory proteins such as chemokines, and facilitating escape from apoptosis. The constitutive expression of chemokines such as CXCL1 has been correlated with growth, angiogenesis, and metastasis of cancers such as melanoma. The transcription of CXCL1 is regulated through interactions of NF-κB with other transcriptional regulatory molecules such as poly(ADP-ribose) polymerase-1 (PARP-1) and cAMP response element binding protein (CREB)-binding protein (CBP). It has been proposed that these two proteins interact with NF-κB and other enhancers to form an enhanceosome at the promoter region of CXCL1 and modulate CXCL1 transcription. In addition to these positive cofactors, a negative regulator, CAAT displacement protein (CDP), may also be involved in the transcriptional regulation of CXCL1. It has been postulated that the elevated expression of CXCL1 in melanomas is due to altered interaction between these molecules. CDP interaction with the promoter down-regulates transcription, whereas PARP and/or CBP interactions enhance transcription. Thus, elucidation of the interplay between components of the enhanceosome of this gene is important in finding more efficient and new therapies for conditions such as cancer as well as acute and chronic inflammatory diseases.
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Affiliation(s)
- Katayoun Izadshenas Amiri
- Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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15
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Boudreau F, Rings EHHM, Swain GP, Sinclair AM, Suh ER, Silberg DG, Scheuermann RH, Traber PG. A novel colonic repressor element regulates intestinal gene expression by interacting with Cux/CDP. Mol Cell Biol 2002; 22:5467-78. [PMID: 12101240 PMCID: PMC133930 DOI: 10.1128/mcb.22.15.5467-5478.2002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2002] [Revised: 03/11/2002] [Accepted: 04/24/2002] [Indexed: 01/19/2023] Open
Abstract
Intestinal gene regulation involves mechanisms that direct temporal expression along the vertical and horizontal axes of the alimentary tract. Sucrase-isomaltase (SI), the product of an enterocyte-specific gene, exhibits a complex pattern of expression. Generation of transgenic mice with a mutated SI transgene showed involvement of an overlapping CDP (CCAAT displacement protein)-GATA element in colonic repression of SI throughout postnatal intestinal development. We define this element as CRESIP (colon-repressive element of the SI promoter). Cux/CDP interacts with SI and represses SI promoter activity in a CRESIP-dependent manner. Cux/CDP homozygous mutant mice displayed increased expression of SI mRNA during early postnatal development. Our results demonstrate that an intestinal gene can be repressed in the distal gut and identify Cux/CDP as a regulator of this repression during development.
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MESH Headings
- Aging/metabolism
- Animals
- COS Cells
- Caco-2 Cells
- Colon/cytology
- Colon/growth & development
- Colon/metabolism
- DNA-Binding Proteins/metabolism
- GATA4 Transcription Factor
- Gene Expression Regulation, Developmental/physiology
- Homeodomain Proteins
- Humans
- In Situ Hybridization
- Intestinal Mucosa/metabolism
- Intestine, Small/cytology
- Intestine, Small/growth & development
- Intestine, Small/metabolism
- Intestines/cytology
- Intestines/growth & development
- Mice
- Mice, Knockout
- Mice, Transgenic
- Mutagenesis, Site-Directed
- Nuclear Proteins/metabolism
- Promoter Regions, Genetic/physiology
- RNA, Messenger/metabolism
- Regulatory Sequences, Nucleic Acid/physiology
- Repressor Proteins/metabolism
- Sucrase-Isomaltase Complex/biosynthesis
- Sucrase-Isomaltase Complex/genetics
- Transcription Factors/metabolism
- Transgenes
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Affiliation(s)
- François Boudreau
- Division of Gastroenterology, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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16
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Snyder SR, Wang J, Waring JF, Ginder GD. Identification of CCAAT displacement protein (CDP/cut) as a locus-specific repressor of major histocompatibility complex gene expression in human tumor cells. J Biol Chem 2001; 276:5323-30. [PMID: 11084046 DOI: 10.1074/jbc.m009454200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Human major histocompatibility (MHC) class I antigen expression is important in controlling the metastatic growth of malignant tumors. Locus-specific down-regulation of MHC class I gene expression is frequently observed in human tumors, leading to decreased susceptibility to cytotoxic T-cell-mediated lysis. The mechanism of this down-regulation is incompletely understood. Here, we describe the identification of human CCAAT displacement protein (CDP/cut) as a locus-specific repressor of HLA-B and C gene expression. Transient and stable transfections in HeLa and K562 cells demonstrated the presence of a repressor element 650 base pairs upstream of the first exon of HLA-B7. A specific binding complex with the HLA-B7 and Cw2 repressor elements was demonstrated by EMSA. Formation of the EMSA complex was inhibited specifically with polyclonal antiserum to human CDP/cut, demonstrating that CDP/cut binds the HLA-B7 repressor element. The corresponding region of the HLA-A2 promoter neither repressed HLA-A2 gene expression nor bound CDP/cut. Overexpression of CDP/cut in cell lines deficient in CDP/cut resulted in a nearly 4-fold repression of reporter constructs containing the HLA-B7 repressor element but not the corresponding region of the HLA-A2 promoter. Repression of HLA-B and C gene expression by CDP/cut does not involve displacement of NF-Y, nor is CDP/cut associated with the histone deacetylase HDAC1 when bound to the HLA-B7 repressor element. To our knowledge, these results identify CDP/cut as the first example of a locus-specific repressor of MHC class I gene transcription in human tumor cells.
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Affiliation(s)
- S R Snyder
- Massey Cancer Center, Medical College of Virginia at Virginia Commonwealth University, Richmond, VA 23298, USA.
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