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Novel thalidomide analogs: Anti-angiogenic and apoptotic effects on Hep-G2 and MCF-7 cancer cell lines. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.biomag.2014.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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2
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Pallai R, Simpkins H, Chen J, Parekh HK. The CCAAT box binding transcription factor, nuclear factor-Y (NF-Y) regulates transcription of human aldo-keto reductase 1C1 (AKR1C1) gene. Gene 2010; 459:11-23. [PMID: 20338228 DOI: 10.1016/j.gene.2010.03.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 03/09/2010] [Accepted: 03/10/2010] [Indexed: 01/01/2023]
Abstract
Dihydrodiol dehydrogenases are a family of aldo-keto reductases (AKR1Cs) involved in the metabolism of steroid hormones and xenobiotics. Herein, we have cloned and characterized the proximal promoter region of the human AKR1C1 gene. The 5' flanking proximal promoter region of the AKR1C1 gene consists of a TATA box and an inverted CCAAT binding site. Deletion analysis of the 5' flanking, approximately 3.0 kb region of the human AKR1C1 gene identified the region between -128 and -88 as the minimal proximal promoter essential for basal transcription of AKR1C1 in human ovarian (2008 and 2008/C13*), lung (H23 and A549) and liver carcinoma (HepG2) cells. Site-directed mutagenesis studies indicated that the transcription factor binding sites for NF-Y/CEBP were involved in controlling the basal transcription of AKR1C1 in all the cancer cells studied. Electrophoretic mobility shift (EMSAs) and gel-supershift assays demonstrated that the transcription factor NF-Y preferentially binds to the inverted CCAAT box at (-109)ATTGG(-105) of the AKR1C1 gene. Chromatin immunoprecipitation (ChIP) analysis confirmed the in vivo association between NF-Y and human AKR1C1 gene promoter in human ovarian, lung and liver carcinoma cells. Ectopic expression of NF-Ys increased the AKR1C1 gene transcription, whereas expression of a dominant-negative NF-YA or suppression of NF-YA decreased the AKR1C1 gene transcription. A 2-fold increase in AKR1C1 transcription was observed specifically in cisplatin-treated 2008 cells that were CCAAT box-dependent. These results indicate that the NF-Y regulates the basal transcription of AKR1C1 in human ovarian, lung and liver carcinoma cells and the cisplatin-induced transcription in human ovarian carcinoma cells.
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Affiliation(s)
- Rajash Pallai
- Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
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3
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Bernadt CT, Nowling T, Rizzino A. Transcription factor Sox-2 inhibits co-activator stimulated transcription. Mol Reprod Dev 2005; 69:260-7. [PMID: 15349837 DOI: 10.1002/mrd.20168] [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] [Indexed: 11/10/2022]
Abstract
Previous studies have shown that transcription of the fibroblast growth factor-4 (FGF-4) gene by early embryonic cells is dependent upon a powerful distal enhancer located 3 kb downstream of the transcription start site within the untranslated region of the last exon. The transcription factors Sox-2 and Oct-3 cooperatively bind to critical cis-regulatory elements within the enhancer to synergistically activate transcription. Moreover, the co-activator p300 can mediate the synergistic activity of Sox-2 and Oct-3, and p300 associates with the FGF-4 enhancer in vivo. Embryonal carcinoma (EC) cells have been used extensively as a model system to study the regulation of the FGF-4 gene during early development. Recently, it has been suggested that suboptimal levels of Sox-2 expression in F9 EC cells limit the transcription of the FGF-4 gene. The studies presented in this report argue that Sox-2 levels are not limiting in F9 EC cells. Moreover, overexpression of Sox-2 in F9 EC cells decreases FGF-4 promoter activity. In addition, overexpression of Sox-2 in these cells inhibits activation by the co-activators p300, CBP, and OCA-B in a manner that requires the transactivation domain of Sox-2. These findings suggest that Sox-2 levels in F9 EC cells are regulated carefully to avoid interference with the transcription of critical genes.
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Affiliation(s)
- Cory T Bernadt
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA
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4
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Bernadt CT, Nowling T, Wiebe MS, Rizzino A. NF-Y behaves as a bifunctional transcription factor that can stimulate or repress the FGF-4 promoter in an enhancer-dependent manner. Gene Expr 2005; 12:193-212. [PMID: 16128003 PMCID: PMC6009113 DOI: 10.3727/000000005783992052] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
NF-Y is a bifunctional transcription factor capable of activating or repressing transcription. NF-Y specifically recognizes CCAAT box motifs present in many eukaryotic promoters. The mechanisms involved in regulating its activity are poorly understood. Previous studies have shown that the FGF-4 promoter is regulated positively by its CCAAT box and NF-Y in embryonal carcinoma (EC) cells where the distal enhancer of the FGF-4 gene is active. Here, we demonstrate that the CCAAT box functions as a negative cis-regulatory element when cis-regulatory elements of the FGF-4 enhancer are disrupted, or after EC cells differentiate and the FGF-4 enhancer is inactivated. We also demonstrate that NF-Y mediates the repression of the CCAAT box and that NF-Y associates with the endogenous FGF-4 gene in both EC cells and EC-differentiated cells. Importantly, we also determined that the orientation and the position of the CCAAT box are critical for its role in regulating the FGF-4 promoter. Together, these studies demonstrate that the distal enhancer of the FGF-4 gene determines whether the CCAAT box of the FGF-4 promoter functions as a positive or a negative cis-regulatory element. In addition, these studies are consistent with NF-Y playing an architectural role in its regulation of the FGF-4 promoter.
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Affiliation(s)
- Cory T. Bernadt
- *Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198-6805
- †Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198-6805
| | - Tamara Nowling
- *Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198-6805
| | - Matthew S. Wiebe
- *Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198-6805
- †Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198-6805
| | - Angie Rizzino
- *Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198-6805
- †Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198-6805
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Nowling T, Bernadt C, Johnson L, Desler M, Rizzino A. The co-activator p300 associates physically with and can mediate the action of the distal enhancer of the FGF-4 gene. J Biol Chem 2003; 278:13696-705. [PMID: 12488456 DOI: 10.1074/jbc.m207567200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Distal enhancers commonly regulate gene expression. However, the mechanisms of transcriptional mediation by distal enhancers remain largely unknown. To better understand distal enhancer-mediated transcription, we examined the regulation of the FGF-4 gene. The FGF-4 gene is regulated during early development by a powerful distal enhancer located downstream of the promoter in exon 3. Sox-2 and Oct-3 bind to the enhancer and are required for the activation of the FGF-4 gene. Previously, we implicated the co-activator p300 as a mediator of Sox-2/Oct-3 synergistic activation of a heterologous promoter, suggesting that p300 may play a role in mediating enhancer activation of the FGF-4 gene. In this study, we provide both functional and physical evidence that p300 plays an important role in the action of the FGF-4 enhancer. Specifically, we show that E1a, but not a mutant form of E1a that is unable to bind p300, inhibits enhancer activation of the FGF-4 promoter. We also demonstrate that Gal4/p300 fusion proteins can stimulate the FGF-4 promoter when bound to the FGF-4 enhancer. Additionally, we present evidence that p300 mediation of the FGF-4 enhancer requires acetyltransferase activity. Importantly, we also show that Sox-2 and p300 are physically associated with the endogenous FGF-4 enhancer but weakly associated with the endogenous FGF-4 promoter. These results are consistent with a model of transitory interaction between the distal enhancer and the FGF-4 promoter. Our results also suggest that intragenic distal enhancers may use mechanisms that differ from extragenic distal enhancers.
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Affiliation(s)
- Tamara Nowling
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha 68198, USA
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6
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Abstract
Embryonic stem (ES) cells are pluripotent stem cells that differentiate both in vitro and in vivo into cell types derived from each of the three embryonic germ layers. ES cells and their close relatives, embryonal carcinoma (EC) cells and embryonic germ (EG) cells, have been used extensively as model systems for studying early mammalian development. This work has led to important insights into the mechanisms that control embryogenesis at the molecular and cellular levels. This chapter focuses on the use of ES cells as an in vitro model system for studying cellular differentiation and reviews several areas where important progress has been made. Impressive progress has been made in the isolation and characterization of ES cells from many species, including humans. Significant progress has also been made in the development of culture conditions that help direct the differentiation of ES cells to specific cell types that form during myogenesis, angiogenesis, hematopoiesis, neurogenesis, and cardiogenesis. The ability to inactivate virtually any gene in ES cells by gene targeting has vastly improved our understanding of the roles played by specific genes at the cellular and organismic levels. Moreover, ES cells and EC cells have been used widely to investigate how specific genes are turned on and turned off in the course of differentiation. In this connection, DNA array technology has been used to identify genes regulated when ES cells differentiate. The final section of this chapter discusses how work with ES cells is shaping our understanding of stem cells, mammalian development, and cell replacement therapy.
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Affiliation(s)
- Angie Rizzino
- Eppley Institute for Cancer Research and Allied Diseases, University of Nebraska Medical Center, 986805 Nebraska Medical Center, Omaha, Nebraska 68198-6805, USA
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7
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Johnson LR, Johnson TK, Desler M, Luster TA, Nowling T, Lewis RE, Rizzino A. Effects of B-Myb on gene transcription: phosphorylation-dependent activity ans acetylation by p300. J Biol Chem 2002; 277:4088-97. [PMID: 11733503 DOI: 10.1074/jbc.m105112200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The transcription factor B-Myb is a cell-cycle regulated phosphoprotein involved in cell cycle progression through the transcriptional regulation of many genes. In this study, we show that the promoter of the fibroblast growth factor-4 (FGF-4) gene is strongly activated by B-Myb in HeLa cells and it can serve as a novel diagnostic tool for assessing B-Myb activity. Specifically, B-Myb deletion mutants were examined and domains of B-Myb required for activation of the FGF-4 promoter were identified. Using phosphorylation-deficient mutant forms of B-Myb, we also show that phosphorylation is essential for B-Myb activity. Moreover, a mutant form of B-Myb, which lacks all identified phosphorylation sites and which has little activity, can function as a dominant-negative and suppress wild-type B-Myb activity. Acetylation is another post-translational modification known to affect the activity of other Myb family members. We show that B-Myb is acetylated by the co-activator p300. We also show that the bromo and histone acetyltransferase domains of p300 are sufficient to interact with and acetylate B-Myb. These data indicate that phosphorylation of B-Myb is an essential modification for activity and that acetylation of B-Myb may play a role in B-Myb activity.
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Affiliation(s)
- Lance R Johnson
- Eppley Institute for Research in Cancer and Allied Diseases, Department of Pathology University of Nebraska Medical Center, Omaha, Nebraska 68198-6805, USA
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Luster TA, Johnson LR, Nowling TK, Lamb KA, Philipsen S, Rizzino A. Effects of three Sp1 motifs on the transcription of the FGF-4 gene. Mol Reprod Dev 2000; 57:4-15. [PMID: 10954851 DOI: 10.1002/1098-2795(200009)57:1<4::aid-mrd3>3.0.co;2-i] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Previous studies have shown that the transcription of the fibroblast growth factor-4 (FGF-4) gene is regulated by a powerful enhancer located approximately three kilobases downstream of the transcription start site. Several conserved cis-regulatory elements in the promoter and the enhancer have been identified, including two Sp1 motifs located in the promoter and one Sp1 motif located in the enhancer. Each of these Sp1 motifs has been shown previously to bind the transcription factors Sp1 and Sp3 in vitro. The main objective of this study was to examine the potential interaction of the FGF-4 promoter and enhancer Sp1 motifs. Using site-directed mutagenesis, we demonstrate that disruption of these sites, individually or in combination, reduce the expression of FGF-4 promoter/reporter gene constructs in embryonal carcinoma cells. Importantly, we demonstrate that disruption of the enhancer Sp1 motif exerts a more pronounced effect on the expression of these constructs than disruption of the promoter Sp1 motifs. We also demonstrate that changing the spacing and the stereo-alignment of the enhancer Sp1 motif, relative to the other cis-regulatory elements of the enhancer, has little effect on the ability of the enhancer to stimulate transcription. Furthermore, embryonic stem cells that contain two disrupted Sp1 alleles were used to demonstrate that the transcription factor Sp1 is not necessary for expression of the endogenous FGF-4 gene. Finally, the significance of these findings relative to a looping model for the transcriptional activation of the FGF-4 gene is discussed.
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Affiliation(s)
- T A Luster
- Eppley Institute for the Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska 68198-6805, USA
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9
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Abstract
In this commentary, we describe a model to explain the mechanism of the embryopathy of thalidomide. We propose that thalidomide affects the following pathway during development: insulin-like growth factor I (IGF-I) and fibroblast growth factor 2 (FGF-2) stimulation of the transcription of alphav and beta3 integrin subunit genes. The resulting alphavbeta3 integrin dimer stimulates angiogenesis in the developing limb bud, which promotes outgrowth of the bud. The promoters of the IGF-I and FGF-2 genes, the genes for their binding proteins and receptors, as well as the alphav and beta3 genes, lack typical TATA boxes, but instead contain multiple GC boxes (GGGCGG). Thalidomide, or a breakdown product of thalidomide, specifically binds to these GC promoter sites, decreasing transcription efficiency of the associated genes. A cumulative decrease interferes with normal angiogenesis, which results in truncation of the limb. Intercalation into G-rich promoter regions of DNA may explain why certain thalidomide analogs are not teratogenic while retaining their anti-tumor necrosis factor-alpha (TNF-alpha) activity, and suggests that we look elsewhere to explain the action of thalidomide on TNF-alpha. On the other hand, the anti-cancer action of thalidomide may be based on its antiangiogenic action, resulting from specific DNA intercalation. The tissue specificity of thalidomide and its effect against only certain neoplasias may be explained by the fact that various developing tissues and neoplasias depend on different angiogenesis or vasculogenesis pathways, only some of which are thalidomide-sensitive.
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Affiliation(s)
- T D Stephens
- Department of Biological Sciences, Idaho State University, Pocatello, ID, USA.
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Wiebe MS, Wilder PJ, Kelly D, Rizzino A. Isolation, characterization, and differential expression of the murine Sox-2 promoter. Gene 2000; 246:383-93. [PMID: 10767561 DOI: 10.1016/s0378-1119(00)00086-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Sox proteins are expressed at many stages of development and in numerous tissues. The transcription factor Sox-2 is first expressed throughout the inner cell mass and subsequently becomes localized to the primitive ectoderm, developing central nervous system, and the lens. Sox-2 is also highly expressed in F9 embryonal carcinoma cells, but becomes undetectable following differentiation of these cells. In this study, we have isolated, sequenced, and performed the first characterization of the Sox-2 promoter of any species. Approximately 2kb of the Sox-2 5'-flanking region has been sequenced and the primary transcription start site mapped by primer extension analysis. Additionally, two positive regulatory regions within the promoter region have been identified. We also show that expression of Sox-2 promoter/reporter gene constructs is reduced in differentiated EC cells as compared to their undifferentiated counterparts. Furthermore, we have identified a consensus inverted CCAAT box motif present in the Sox-2 promoter. Mutagenesis of this site significantly reduces the expression of Sox-2 promoter/reporter constructs. We also demonstrate that this CCAAT box motif can bind the trimeric transcription factor NF-Y.
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Affiliation(s)
- M S Wiebe
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198-6805, USA
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11
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Abstract
We propose that thalidomide affects the following pathway during limb development: Growth factors (FGF-2 and IGF-I) attach to receptors on limb bud mesenchymal cells and initiate some second messenger system (perhaps SP-1), which activates alphav and beta3 integrin subunit genes. The resulting alphav beta3 integrin proteins stimulate angiogenesis in the developing limb bud. Several steps in this pathway depend on the activation of genes with primarily GC promoters (GGGCGG). Thalidomide, or a hydrolysis or metabolic breakdown product, specifically binds to GC promoter sites and inhibits the transcription of those genes. Inhibition of the genes interferes with normal angiogenesis, which results in truncation of the limb.
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Affiliation(s)
- T D Stephens
- Department of Biological Sciences, Idaho State University, Pocatello, Idaho 83209, USA.
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12
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Park GT, Morasso MI. Regulation of the Dlx3 homeobox gene upon differentiation of mouse keratinocytes. J Biol Chem 1999; 274:26599-608. [PMID: 10473625 PMCID: PMC1317293 DOI: 10.1074/jbc.274.37.26599] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Distal-less Dlx3 homeodomain gene is expressed in terminally differentiated murine epidermal cells, and there is evidence to support an essential role as a transcriptional regulator of the terminal differentiation process in these cells. In an attempt to determine the factors that induce Dlx3 gene expression, we have cloned the 1.2-kilobase pair proximal region of murine gene and analyzed its cis-regulatory elements and potential trans-acting factors. The proximal region of the Dlx3 gene has a canonical TATA box and CCAAT box, and the transcription start site was located 205 base pairs upstream from the initiation of translation site. Serial deletion analysis showed that the region between -84 and -34 confers the maximal promoter activity both in undifferentiated and differentiated primary mouse keratinocytes. Gel retardation assays and mutational analysis demonstrated that the transcriptional regulator NF-Y (also referred to as CBF) binds to a CCAAT box motif within this region and is responsible for the majority of the Dlx3 promoter activity. In addition, an Sp1-binding site was located immediately upstream of transcription start site that acts as a positive regulatory element of the Dlx3 promoter, independent of the CCAAT box motif. Importantly, elements residing between +30 to +60 of the Dlx3 gene are responsible for the Ca(2+)-dependent induction of Dlx3 during keratinocyte differentiation.
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Affiliation(s)
- Geon Tae Park
- From the Laboratory of Skin Biology, NIAMS, National Institutes of Health, Bethesda, Maryland 20892
| | - Maria I. Morasso
- From the Laboratory of Skin Biology, NIAMS, National Institutes of Health, Bethesda, Maryland 20892
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Lamb KA, Rizzino A. Effects of differentiation on the transcriptional regulation of the FGF-4 gene: critical roles played by a distal enhancer. Mol Reprod Dev 1998; 51:218-24. [PMID: 9740330 DOI: 10.1002/(sici)1098-2795(199810)51:2<218::aid-mrd12>3.0.co;2-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Embryonal carcinoma (EC) cells are used widely as a model system for studying the expression of developmentally regulated genes, in particular genes that are regulated at the transcriptional level when EC cells differentiate. This review focuses on the molecular mechanisms that govern the transcription of the fibroblast growth factor-4 (FGF-4) gene, which appears to be the first FGF expressed during mammalian development. Interest in this gene has increased considerably with the finding that FGF-4 is essential for mammalian embryogenesis. The FGF-4 gene has also generated considerable interest because it is inhibited at the transcriptional level when EC cells undergo differentiation and because this gene is regulated by a powerful distal enhancer located 3 kb downstream of the transcription start site in the last exon of the gene. Hence, study of the FGF-4 gene is likely to shed light on the molecular mechanisms by which distal enhancers regulate gene expression. In addition to being regulated by the downstream enhancer, the expression of this gene is influenced by a regulatory region located just upstream of the transcription start site, which contains two Sp1 motifs and a CCAAT box motif. Examination of the downstream enhancer has identified three functional cis-regulatory elements: a high mobility group (HMG) protein binding motif, an octamer binding motif, and an Sp1 motif, which are likely to bind Sox-2, Oct-3, and Sp1/Sp3, respectively, in vivo. Interestingly, Sox-2 and Oct-3 expression, like FGF-4 expression, decreases when EC cells differentiate, which suggests that the loss of these transcription factors is responsible, at least in part, for the transcriptional turn-off of the FGF-4 gene. In view of these and other findings, we present a model for the differential expression of the FGF-4 gene that includes not only the contributions of specific transcription factors, but also the contribution of chromatin structure before and after differentiation.
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Affiliation(s)
- K A Lamb
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha 68198-6805, USA
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14
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Kelly D, Kim SJ, Rizzino A. Transcriptional activation of the type II transforming growth factor-beta receptor gene upon differentiation of embryonal carcinoma cells. J Biol Chem 1998; 273:21115-24. [PMID: 9694866 DOI: 10.1074/jbc.273.33.21115] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Previously, it has been shown that differentiation of embryonal carcinoma (EC) cells turns on the expression of functional transforming growth factor type-beta receptors. Here, we show that the type II receptor (TbetaR-II) gene is activated at the transcriptional level when EC cells differentiate. We show that the differentiated cells, but not the parental EC cells, express transcripts for TbetaR-II. In addition, the expression of TbetaR-II promoter/reporter gene constructs are elevated dramatically when EC cells differentiate and we identify at least two positive and two negative regulatory regions in the 5' flanking region of the TbetaR-II gene. Moreover, we identify a cAMP response element/activating transcription factor site that acts as a positive cis-regulatory element in the TbetaR-II promoter, and we demonstrate that the transcription factor ATF-1 binds to this site and strongly stimulates the expression of the TbetaR-II promoter/reporter gene constructs when ATF-1 is overexpressed in EC-derived differentiated cells. Equally important, we identify a negative regulatory element in a 53-base pair region that had previously been shown to inhibit strongly the expression of TbetaR-II promoter/reporter gene constructs. Specifically, we demonstrate that this region, which contains an inverted CCAAT box motif, binds the transcription factor complex NF-Y (also referred to as CBF) in vitro. Furthermore, expression of a dominant-negative NF-YA mutant protein, which prevents DNA binding by NF-Y, enhances TbetaR-II promoter expression. Together, these studies suggest that the transcription factors ATF-1 and NF-Y play important roles in the regulation of the TbetaR-II gene.
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MESH Headings
- Activating Transcription Factor 1
- Animals
- Base Sequence
- CCAAT-Enhancer-Binding Proteins
- Carcinoma, Embryonal/genetics
- Carcinoma, Embryonal/metabolism
- Carcinoma, Embryonal/pathology
- Cell Differentiation
- Cell Line
- DNA
- DNA-Binding Proteins/metabolism
- Gene Expression Regulation, Neoplastic
- Mice
- Nuclear Proteins/metabolism
- Promoter Regions, Genetic
- Protein Binding
- Protein Serine-Threonine Kinases
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptor, Transforming Growth Factor-beta Type II
- Receptors, Transforming Growth Factor beta/genetics
- Receptors, Transforming Growth Factor beta/metabolism
- Regulatory Sequences, Nucleic Acid
- Transcription Factors/metabolism
- Transcriptional Activation
- Transforming Growth Factor beta/metabolism
- Tumor Cells, Cultured
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Affiliation(s)
- D Kelly
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA
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15
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Johnson LR, Lamb KA, Gao Q, Nowling TK, Rizzino A. Role of the transcription factor Sox-2 in the expression of the FGF-4 gene in embryonal carcinoma cells. Mol Reprod Dev 1998; 50:377-86. [PMID: 9669521 DOI: 10.1002/(sici)1098-2795(199808)50:4<377::aid-mrd1>3.0.co;2-f] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
It has been shown previously that the FGF-4 gene is regulated by a powerful downstream enhancer in embryonal carcinoma (EC) cells. This enhancer contains an essential HMG motif; however, the transcription factor that binds to the HMG motif in EC cells has not been determined definitively. In earlier studies, this HMG motif was shown to bind a heat-stable, redox-insensitive factor expressed by F9 EC cells. Others have proposed that the transcription factor Sox-2 binds to the FGF-4 enhancer HMG motif. In this study, we demonstrate that the N-terminal half of Sox-2, which contains the DNA binding domain, binds to the FGF-4 enhancer HMG motif and we show that this binding is unaffected by heat and oxidation. In addition, we employed two experimental approaches to demonstrate that Sox-2 regulates the transcription of the FGF-4 gene in EC cells. As part of these studies, an expression plasmid that codes for a dominant-negative form of Sox-2 was used in transient expression assays. In other experiments, a Sox-2 antisense expression plasmid was used. When co-transfected into F9 EC cells along with an FGF-4 promoter/reporter gene construct, each expression plasmid caused a significant reduction in reporter activity. Our studies also demonstrate that Sox-2 affects the expression of the FGF-4 gene in the multipotent EC cell line, P19. Taken together, these studies argue strongly that Sox-2 plays an important role in the expression of the FGF-4 gene in vivo.
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Affiliation(s)
- L R Johnson
- Eppley Institute for Cancer Research and Allied Diseases, University of Nebraska Medical Center, Omaha 68198-6805, USA
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