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Cavazzana A, Prayer-Galetti T, Tirabosco R, Macciomei M, Stella M, Lania L, Cannada-Bartoli P, Passerini-Glazel L, Pagano F. Bellini Duct Carcinoma. Eur Urol 2017. [DOI: 10.1159/000474193] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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2
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Abstract
A significant amount of experimental evidence has demonstrated that progression of the cell cycle in mammalian cells is associated with periodic transcriptional activation/ repression of growth-regulatory genes. We summarize our current knowledge and views on the role of the critical cell cycle regulators such as the retinoblastoma proteins in transcription repression and their functional connections with various different transcription factors. In addition, we discuss the role of oncogenes such as TIF1 alpha, PML and RFL which belong to a characteristic subgroup of RING finger proteins that contain the RING finger (C3HC4 zinc finger) the B-boxes and a putative coiled-coil (RBCC configuration) as mediators of transcription repression.
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Affiliation(s)
- L Lania
- CNR,INT INST GENET & BIOPHYS,I-80125 NAPLES,ITALY
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3
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Fraldi A, Licciardo P, Majello B, Giordano A, Lania L. Distinct regions of cyclinT1 are required for binding to CDK9 and for recruitment to the HIV-1 Tat/TAR complex. J Cell Biochem Suppl 2001; Suppl 36:247-53. [PMID: 11455589 DOI: 10.1002/jcb.1149] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Tat-mediated activation of the HIV-1 promoter activity requires Tat-dependent recruitment of the cyclinT1/CDK9 complex (P-TEFb) to the transacting element (TAR) RNA. Tat interaction with the cyclinT1, the regulatory partner of CDK9, results in a specific recruitment of the heterodimer CycT1/CDK9 complex to TAR, whereby it promotes transcription elongation of the HIV-1 LTR-mediated transcription. Using the yeast two-hybrid protein interaction assay we analyzed the binding between cyclinT1 and CDK9. Moreover, using a modified three-hybrid yeast interaction system, we analyzed the recruitment of CycT1 to the Tat/TAR complex. The data presented here demonstrated that distinct domains of cyclinT1 interact with CDK9 and Tat/TAR in vivo. These findings will be instrumental for the designing of proper dominant-negative P-TEFb components capable to interfere with Tat function. J. Cell. Biochem. Suppl. 36: 247-253, 2001.
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Affiliation(s)
- A Fraldi
- Department of Genetics, Molecular and General Biology, University Federico II, Via Mezzocannone 8, 80134 Naples, Italy
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Licciardo P, Ruggiero L, Lania L, Majello B. Transcription activation by targeted recruitment of the RNA polymerase II CTD phosphatase FCP1. Nucleic Acids Res 2001; 29:3539-45. [PMID: 11522823 PMCID: PMC55871 DOI: 10.1093/nar/29.17.3539] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human FCP1 in association with RNAP II reconstitutes a highly specific CTD phosphatase activity and is required for recycling RNA polymerase II (RNAP II) in vitro. Here we demonstrate that targeted recruitment of FCP1 to promoter templates, through fusion to a DNA-binding domain, stimulates transcription. We demonstrate that a short region at the C-terminus of the FCP1 protein is required and sufficient for activation, indicating that neither the N-terminal phosphatase domain nor the BRCT domains are required for transcription activity of DNA-bound FCP1. In addition, we demonstrate that the C-terminus region of FCP1 suffices for efficient binding in vivo to the RAP74 subunit of TFIIF and is also required for the exclusive nuclear localization of the protein. These findings suggest a role for FCP1 as a positive regulator of RNAP II transcription.
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Affiliation(s)
- P Licciardo
- Department of Genetics, General and Molecular Biology, University of Naples 'Federico II' and IIGB, CNR, Naples, Italy
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5
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Abstract
OBJECTIVES To asses the role of the RNAPII carboxy-terminal domain (CTD) phosphatase FCP1 on HIV-1 Tat-mediated transactivation. DESIGN Construction of expression vectors encoding FCP1 phosphatase and analysis of their functions on Tat activity. METHODS Basal and Tat-mediated transactivation of HIV-1 long terminal repeat (LTR)-driven transcription was compared, by transient transfections, in the presence of FCP1 phosphatase. Protein interactions were analysed by in vitro binding assays. RESULTS FCP1 specifically and effectively represses Tat transactivation but not HIV-1 LTR-basal transcription. Protein interaction assays demonstrated that FCP1 specifically and directly binds Tat in vitro. CONCLUSION The specific and efficient inhibitory function of FCP1 highlights the important role of this CTD-phosphatase in Tat-mediated transactivation, and it suggests that FCP1 might represent a specific target for modulation of Tat activity in infected cells.
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Affiliation(s)
- P Licciardo
- Department of Genetics, Molecular and General Biology, University of Naples Federico II and the International Institute of Genetics and Biophysics, Italy
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Napolitano G, Majello B, Licciardo P, Giordano A, Lania L. Transcriptional activity of positive transcription elongation factor b kinase in vivo requires the C-terminal domain of RNA polymerase II. Gene 2000; 254:139-45. [PMID: 10974544 DOI: 10.1016/s0378-1119(00)00278-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phosphorylation of the carboxyl-terminal domain (CTD) of RNA polymerase II (RNAPII) is an important step in transcription and the positive transcription elongation factor b (P-TEFb) has been proposed to facilitate elongation at many genes. The P-TEFb contains a catalytic subunit (Cdk9) that, in association with a cyclin subunit (cyclinT1), has the ability to phosphorylate the CTD substrate in vitro. Here, we demonstrate that cyclinT1/Cdk9-mediated transcription requires CTD-containing RNAPII, suggesting that the CTD is the major target of the cyclinT1/Cdk9 complex in vivo. Unlike Cdk7 and Cdk8, two other cyclin-dependent kinases that are capable of phosphorylating the CTD in vitro, we found that only the Cdk9 activates gene expression in a catalysis-dependent manner. Finally, unlike cyclinT1 and T2, we found that the targeted recruitment to promoter DNA of cyclinK (a recently described alternative partner of Cdk9) does not stimulate transcription in vivo. Collectively, our data strongly indicate that the P-TEFb kinase subunits cyclinT/Cdk9 are specifically involved in transcription and the CTD domain of RNAPII is the major functional target of this complex in vivo.
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Affiliation(s)
- G Napolitano
- Department of Genetics, Molecular and General Biology, University of Naples 'Federico II' and International Institute of Genetics and Biophysics, CNR, Via Mezzocannone 8, 80134, Naples, Italy
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Pagliuca A, Gallo P, Lania L. Differential role for Sp1/Sp3 transcription factors in the regulation of the promoter activity of multiple cyclin-dependent kinase inhibitor genes. J Cell Biochem 2000. [PMID: 10649433 DOI: 10.1002/(sici)1097-4644(20000301)76:3<360::aid-jcb3>3.0.co;2-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Cyclin-dependent kinase inhibitors play a significant role in cell cycle progression and in cellular differentiation and their expression is regulated in different cellular settings. GC-rich regions in the promoter sequences of the cyclin-dependent kinase inhibitor genes p15INK4B and p21CIP1/WAF1 mediate the transcriptional response of these genes to extracellular stimuli. Similar GC-rich sequences in the promoter of the p15INK4A and p16INK4B gene can be targeted for transcriptional inactivation by methylation of cytosine residues. GC-rich regions represent putative target sites for binding of the ubiquitously expressed Sp1 and Sp3 transcription factors. Using a combination of functional and biochemical studies, we analyzed the potential role of the Sp1 and Sp3 factors in the regulation of CDKI p15, p16, and p21 promoter activities. Using transient reporter gene assays, we determined that Sp1 is a strong activator of these promoters, whereas Sp3 functions as a weak transactivator. We have identified multiple protein-binding sites in the proximal promoter sequences of these genes by footprinting analysis. Some of these sites are bound by Sp1 and Sp3, as demonstrated by gel-shift experiments using Sp1/Sp3-specific antibodies, permitting the demonstration that a differential role exists for Sp1 and Sp3 in the regulation of the activity of these promoters.
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Affiliation(s)
- A Pagliuca
- Department of Genetics, Molecular and General Biology, University of Naples "Federico II," 80134 Naples, Italy
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Fedele M, Benvenuto G, Pero R, Majello B, Battista S, Lembo F, Vollono E, Day PM, Santoro M, Lania L, Bruni CB, Fusco A, Chiariotti L. A novel member of the BTB/POZ family, PATZ, associates with the RNF4 RING finger protein and acts as a transcriptional repressor. J Biol Chem 2000; 275:7894-901. [PMID: 10713105 DOI: 10.1074/jbc.275.11.7894] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have identified a novel human gene encoding a 59-kDa POZ-AT hook-zinc finger protein (PATZ) that interacts with RNF4, a mediator of androgen receptor activity, and acts as a transcriptional repressor. PATZ cDNA was isolated through a two-hybrid interaction screening using the RING finger protein RNF4 as a bait. In vitro and in vivo interaction between RNF4 and PATZ was demonstrated by protein-protein affinity chromatography and coimmunoprecipitation experiments. Such interaction occurred through a small region of PATZ containing an AT-hook DNA binding domain. Immunofluorescence staining and confocal microscopy showed that PATZ localizes in distinct punctate nuclear regions and colocalizes with RNF4. Functional analysis was performed by cotransfection assays: PATZ acted as a transcriptional repressor, whereas its partner RNF4 behaved as a transcriptional activator. When both proteins were overexpressed a strong repression of the basal transcription was observed, indicating that the association of PATZ with RNF4 switches activation to repression. In addition, RNF4 was also found to associate with HMGI(Y), a chromatin-modeling factor containing AT-hook domains.
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Affiliation(s)
- M Fedele
- Centro di Endocrinologia ed Oncologia Sperimentale del CNR "G. Salvatore" Dipartimento di Biologia e Patologia Cellulare e Molecolare "L. Califano" Università degli Studi di Napoli "Federico II" via S. Pansini, 5, 80131 Napoli, Italy
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Pagliuca A, Gallo P, De Luca P, Lania L. Class A helix-loop-helix proteins are positive regulators of several cyclin-dependent kinase inhibitors' promoter activity and negatively affect cell growth. Cancer Res 2000; 60:1376-82. [PMID: 10728702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
The class A of basic helix-loop-helix (bHLH) proteins are ubiquitously expressed transcription factors playing a pivotal role in the regulation of cell growth and differentiation. We determined that enforced expression of all four different mammalian members of this family, E12, E47, E2-2, and HEB, suppresses the cell colony-forming efficiency of several cell lines. To gain insights into the mechanisms by which class A bHLH factors affect cell growth, we have investigated their role in the transcriptional regulation of cyclin-dependent kinase inhibitors. We found that p21CIP1/ WAF1, p15INK4B, and p16INK4B promoter sequences contain E-boxes that render these genes competent for class A bHLH-mediated transcriptional activation and Id-mediated repression. The mechanism underlying the class A bHLH-mediated inhibition of cell growth does not involve an arrest of G1 progression in 293T cells. In fact, contrary to what has been found in 3T3 NIH fibroblasts, we found that enhanced expression of class A bHLH proteins led to a decreased proliferation rate by promoting cell death associated with the induction of apoptosis. These findings highlight the role of the class A bHLH proteins as general negative regulators of cell proliferation through a mechanism(s) that involves both enhancement of several cyclin-dependent kinase inhibitor genes expression and promotion of cell death.
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Affiliation(s)
- A Pagliuca
- Department of Genetics, Molecular and General Biology, University of Naples Federico II, Italy
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10
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Abstract
Cyclin-dependent kinase inhibitors play a significant role in cell cycle progression and in cellular differentiation and their expression is regulated in different cellular settings. GC-rich regions in the promoter sequences of the cyclin-dependent kinase inhibitor genes p15INK4B and p21CIP1/WAF1 mediate the transcriptional response of these genes to extracellular stimuli. Similar GC-rich sequences in the promoter of the p15INK4A and p16INK4B gene can be targeted for transcriptional inactivation by methylation of cytosine residues. GC-rich regions represent putative target sites for binding of the ubiquitously expressed Sp1 and Sp3 transcription factors. Using a combination of functional and biochemical studies, we analyzed the potential role of the Sp1 and Sp3 factors in the regulation of CDKI p15, p16, and p21 promoter activities. Using transient reporter gene assays, we determined that Sp1 is a strong activator of these promoters, whereas Sp3 functions as a weak transactivator. We have identified multiple protein-binding sites in the proximal promoter sequences of these genes by footprinting analysis. Some of these sites are bound by Sp1 and Sp3, as demonstrated by gel-shift experiments using Sp1/Sp3-specific antibodies, permitting the demonstration that a differential role exists for Sp1 and Sp3 in the regulation of the activity of these promoters.
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Affiliation(s)
- A Pagliuca
- Department of Genetics, Molecular and General Biology, University of Naples "Federico II," 80134 Naples, Italy
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11
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Abstract
OBJECTIVES To examine the functional interaction between HIV-1 Tat protein and the cyclin T1 and T2 proteins which, in association with cyclin dependent kinase (CDK)9, are the regulatory subunits of the TAK/P-TEFb cellular complex strictly required for Tat transactivation. DESIGN HIV-1 long terminal repeat (LTR) reporter plasmid was co-transfected into human and rodent cells with expression vectors encoding Tat and vectors encoding the cyclins T1, T2a and T2b, respectively. METHODS Tat-mediated transactivation of HIV-1 LTR-driven transcription was compared in the presence or absence of different cyclins T (T1, T2a and T2b), upon co-transfections into human and rodent cell lines. Protein interactions were analysed by in vitro binding assays. RESULTS It was found that Tat function in rodent cells is enhanced by co-expression of cyclin T1 but not cyclin T2. The N-terminal region (amino acids 1-290) of cyclin T1 is sufficient for this function and for binding to Tat and CDK9. Cyclin T2 binds to CDK9 but not to Tat. Moreover, enforced expression of cyclin T2 inhibits cyclin T1-mediated enhancement of Tat in rodent cells and it represses Tat activity in human cells. CONCLUSION Efficient Tat transactivation in rodent cells occurs in the presence of human cyclin T1 but not in the presence of cyclin T2; overexpression of cyclin T2 inhibits Tat function in both rodent and human cells.
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Affiliation(s)
- G Napolitano
- Department of Genetics, University of Naples Federico II, and International Institute of Genetics and Biophysics, Italy
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12
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Abstract
The CDK9 kinase in association with Cyclin T is a component of the transcription positive-acting complex pTEFb which facilitates the transition from abortive to productive transcription elongation by phosphorylating the carboxyl-terminal domain of RNA polymerase II. The Cyclin T1/CDK9 complex is implicated in Tat transactivation, and it has been suggested that Tat functions by recruiting this complex to RNAPII through cooperative binding to RNA. Here, we demonstrate that targeted recruitment of Cyclin T1/CDK9 kinase complex to specific promoters, through fusion to a DNA-binding domain of either Cyclin T1 or CDK9 kinase, stimulates transcription in vivo. Transcriptional enhancement was dependent on active CDK9, as a catalytically inactive form had no transcriptional effect. We determined that, unlike conventional activators, DNA-bound CDK9 does not activate enhancerless TATA-promoters unless TBP is overexpressed, suggesting that CDK9 acts in vivo at a step subsequent to TFIID recruitment DNA-bound. Finally, we determined that CDK9-mediated transcriptional activation is mediated by preferentially stimulating productive transcription elongation.
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Affiliation(s)
- B Majello
- Department of Genetics, Molecular and General Biology, University of Naples 'Federico II' and International Institute of Genetics and Biophysics, CNR, Naples, Italy
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13
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Rossi C, Gibellini D, Barbanti-Brodano G, Betti M, Boarini C, Pengue G, Lania L, Caputo A. Transiently transfected and stably integrated HIV-1 LTR responds differentially to the silencing activity of the Krüppel-associated box (KRAB) transcriptional repressor domain. J Med Virol 1999; 58:264-72. [PMID: 10447422 DOI: 10.1002/(sici)1096-9071(199907)58:3<264::aid-jmv12>3.0.co;2-v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
It has been demonstrated previously that the transcriptional repressor domain called the Krüppel-associated box (KRAB), conserved in a large number of Krüppel-type zinc finger proteins, fused to Tat transdominant negative mutants, is able to silence HIV-1 long terminal repeat (LTR)-driven gene expression in transient transfection assays. In the present study chimeric Tat mutant-KRAB retroviral expression vectors were used to control HIV-1 replication in acutely infected cells. It was found that while transient and stable expression of Tat mutant-KRAB chimeric proteins represses HIV-1 LTR-driven gene transcription in transient assays, stable expression of Tat mutant-KRAB chimeric molecules does not confer resistance to HIV-1 infection in Jurkat T lymphocytic cell lines. The results provide further evidence that transient transfection may underestimate the role of chromosomal structure in transcriptional regulation and highlight the caveat of direct extrapolation of transient results for designing gene therapy strategies for efficient control of HIV-1 infection.
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Affiliation(s)
- C Rossi
- Department of Experimental and Diagnostic Medicine, University of Ferrara, Italy
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14
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Abstract
In eukaryotes, progression of the cell cycle is associated with periodic transcription activation/repression of growth-regulatory genes. We summarize here current knowledge and views on the role of critical cell-cycle regulators such as the retinoblastoma pocket family members and cyclin-dependent kinases in the regulation of gene transcription. In particular, we discuss here the role of specific cyclin-dependent kinase complexes in the regulation of basal transcription. Although the functional connections between transcription and cell-cycle regulators is far from being understood, recent progress has been made in connecting cell-cycle progression to dedicated components of the RNA polymerase II transcription apparatus complex.
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Affiliation(s)
- L Lania
- Department of Genetics, Molecular and General Biology, University of Naples Federico II, Italy.
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15
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Abstract
OBJECTIVES To examine the functional interaction between HIV-1 Tat protein and the TATA-binding protein (TBP). DESIGN HIV long terminal repeat reporter plasmids were cotransfected into mammalian and Drosophila insect cells with expression vectors encoding Tat and vectors encoding TBP either alone or linked to an heterologous DNA-binding domain. METHODS The activity of the different reporters was compared in the presence or absence of Tat or TBP, or both, upon cotransfections into human and Drosophila insect cell lines. RESULTS Tat protein is unable to transactivate enhancerless HIV-1 minimal promoter bearing only the TATA box and TAR. Artificial recruitment of human TBP (hTBP) to the enhancerless HIV minimal promoter was found to trigger gene expression and coexpression of Tat resulted in a marked synergy. Tat protein cooperated with DNA-bound hTBP by inducing high levels of processive viral transcripts. Synergy between Tat and hTBP was also observed when both factors were targeted to a promoter DNA template. The functional cooperation between TBP and Tat was further demonstrated using the Drosophila Schneider SL2 cells. In these cells Tat protein alone was ineffective; however, coexpression of Drosophila TBP and Tat resulted in a trans-activating response region-dependent synergistic transactivation of basal transcription. CONCLUSION The strong synergy between TBP and Tat in the absence of any DNA-bound activator suggests that Tat stimulates transcription in an activator-independent manner most likely by a functional interaction with general transcription factors that occurs after TBP recruitment. Thus, efficient recruitment of TBP represents a limiting step for Tat transactivation.
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Affiliation(s)
- B Majello
- Department of Genetics, Molecular and General Biology, University of Naples Federico II, Italy
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16
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Abstract
The retinoblastoma (RB) tumour suppressor protein negatively regulates cell proliferation by modulating transcription of growth-regulatory genes. Recruitment of Rb to promoters, by association with E2F complex or by fusion with heterologous DNA-binding domains, demonstrated that Rb represses directly transcription. Recent studies also suggest that the RB protein is able to repress gene transcription mediated by the RNA polymerase I and III. Since the TATA-binding protein (TBP) is an important component for transcription mediated by all three RNA polymerases, we have analysed the functional interaction between Rb and TBP in vivo in the context of RNA pol II-driven transcription. We demonstrated that in mammalian cells Rb tethered to promoter represses TBP-mediated activation in vivo, and Rb-mediated repression is reversed in the presence of the inhibition of histone deacetylase activity by trichostatin A (TSA).
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Affiliation(s)
- P De Luca
- Department of Genetics, Molecular and General Biology, University of Naples Federico II, Italy
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17
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Abstract
An increasing body of evidence suggests that eukaryotic activators stimulate polymerase II transcription by facilitating the assembly of the functional basal machinery at the promoter. Here we describe experiments that provide added support for the idea that recruitment of TATA-binding protein (TBP) is a rate-limiting step for transcription activation in mammalian cells. We found that, in human cell lines, recruitment of TBP to a promoter, as a GAL4-TBP fusion protein, can provide a substantial activation of transcription. Activation mediated by the hTBP, tethered to promoter DNA, is strictly dependent upon the presence of a functional TATA element, and it directs faithful transcription initiation. Interestingly, GAL4-hTBP activation was not observed from initiator (Inr) -dependent TATA-less promoters. These results suggest that TBP binding to DNA is not a rate-limiting step for the initial stages of TFIID recruitment to initiator-dependent TATA-less promoters. Finally, we provide evidence that synergy between GAL4-hTBP and defined transcription domains is restricted to activators, such as VP16 and Tat, which are likely to function at steps subsequent to the TFIID recruitment. These findings strengthen the idea that recruitment of TBP represents an important mechanism of activation of TATA-dependent promoters, and on the other hand, they suggest that TBP-DNA interactions are largely dispensable for specific transcription of initiator dependent TATA-less promoters.
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Affiliation(s)
- B Majello
- Department of Genetics, Molecular and General Biology, University of Naples "Federico II," via Mezzocannone 8, 80134 Naples, Italy
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Pagliuca A, Cannada-Bartoli P, Lania L. A role for Sp and helix-loop-helix transcription factors in the regulation of the human Id4 gene promoter activity. J Biol Chem 1998; 273:7668-74. [PMID: 9516472 DOI: 10.1074/jbc.273.13.7668] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Id family helix-loop-helix (HLH) proteins are involved in the regulation of proliferation and differentiation of several cell types. To identify cis- and trans-acting factors that regulate Id4 gene expression, we have analyzed the promoter regulatory sequences of the human Id4 gene in transient transfections and gel mobility shift assays. We have identified two functional elements, both located downstream from the TATA motif, that control Id4 promoter activity. One element contains a consensus E-box, and we demonstrated that the protein complex binding to the E-box contains the bHLH-zip upstream stimulatory factor (USF) transcription factor. Enforced expression of USF1 leads to E-box-mediated stimulation of promoter activity. The E-box also mediated stimulatory effects of several bHLH transcription factors, and co-expression of Id4 blocked the stimulatory effect mediated by the bHLH factors. A second element is a GA motif, located downstream from the transcriptional start sites, mutation of which resulted in a 20-fold increase in transcriptional activity. Gel-shift analysis and transfections into Drosophila Schneider SL2 cells showed that the repressor element is recognized by both Sp1 and Sp3 factors. These data suggest that Id4 transcription control is highly complex, involving both negative and positive regulatory elements, including a novel inhibitory function exerted by Sp1 and Sp3 transcription factors.
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Affiliation(s)
- A Pagliuca
- Department of Genetics, Molecular and General Biology, University of Naples "Federico II," via Mezzocannone 8, 80134 Naples, Italy
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19
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Abstract
Sp1 is one of the very first cellular transcription factors to be identified and cloned in virtue of its binding to a G-rich motif in the SV40 early promoter. Sp1 protein binds to the G-rich sequences present in a variety of cellular and viral promoters and stimulates their transcriptional activity. Recently, a number of other GC and/or GT box-binding factors homologous to Sp1 have been isolated, namely Sp2, Sp3 and Sp4, and the two more distantly related factors, BTEB and BTEB2. The discovery of this family highlights a previously unknown level of complexity of transcriptional regulation of promoters containing GC and/or GT box motifs. This review focuses primarily on strategies aimed to elucidate the transcription properties of the Sp1-like factors and discusses the experimental problems inherent in the attempt to define their respective functions.
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Affiliation(s)
- L Lania
- Department of Genetics, Molecular and General Biology, University of Naples, Federico II, Italy
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20
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Abstract
Sp3 is a member of the Sp family of transcription factors and binds to DNA with affinity and specificity comparable to that of Sp1. We demonstrate that Sp3 is a bifunctional transcription factor that can both activate and repress transcription. Gene fusion experiments in mammalian cells demonstrate that the Sp3 activation potential is distributed over an extensive glutamine-rich N-terminal region, whereas the repressor activity has been mapped in a 72-amino acid region located at the 5' of the zinc finger DNA-binding domain. We demonstrated that the repression activity is strictly dependent on the context of the DNA-binding sites bound by Sp3. We found that Sp3 represses transcription of promoters bearing multiple GAL4 DNA-binding sites, whereas it activates isogenic reporters containing a single GAL4-binding site. Transfection experiments in Drosophila cells that lack endogenous Sp activity demonstrated that Sp3 does not possess an active repression domain that can function in insect cells, rather it is a weak transcriptional activator of the c-myc promoter. Our results strongly suggest that Sp3 is a dual-function regulator whose activity is dependent upon both the promoter and the cellular context.
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Affiliation(s)
- B Majello
- Department of Genetics, Molecular and General Biology, University of Naples "Federico II," via Mezzocannone 8, 80134 Naples 10, Italy
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21
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Abstract
OBJECTIVES To examine the interaction of the HIV Tat protein and the inhibitory domain of the cellular transcription factor Oct-2. DESIGN HIV reporter plasmids were co-transfected with expression vectors encoding wild-type and mutant Tat proteins and vectors encoding the inhibitory domain either alone or linked to a DNA-binding domain. METHODS The activity of the different reporters was compared in the presence or absence of Tat or the inhibitory domain, or both. RESULTS In the presence of the Tat protein, the Oct-2 inhibitory domain enhances the activation of Tat-responsive promoters by Tat. This effect is not observed when either the inhibitory domain or Tat cannot bind to the target gene, but is observed when one or both of the factors can bind. No activation is observed when the Oct-2 domain is co-transfected with Tat mutants that lack the Tat activation domain, indicating that the Oct-2 domain cannot substitute for the Tat activation domain. CONCLUSION These data indicate that the Oct-2 inhibitory domain can functionally interact with Tat to form a complex with enhanced transactivating ability.
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Affiliation(s)
- Y Z Liu
- Department of Molecular Pathology, University College London Medical School, UK
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22
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Liu YZ, Dawson SJ, Gerster T, Friedl E, Pengue G, Matthias P, Lania L, Latchman DS. The ability of the inhibitory domain of the POU family transcription factor Oct-2 to interfere with promoter activation by different classes of activation domains is dependent upon the nature of the basal promoter elements. J Biol Chem 1996; 271:20853-60. [PMID: 8702841 DOI: 10.1074/jbc.271.34.20853] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The Oct-2 transcription factor contains an inhibitory domain which is able to repress transcription following DNA binding. Here we show that within the neuronally expressed Oct-2.5 form, the inhibitory domain can strongly inhibit activation by transcription factor activation domains which are either composed predominantly of acidic residues or contain the HOB motif, whereas it has a weaker effect or no effect on proline-rich activation domains and on a glutamine-rich domain. In contrast, the isolated inhibitory domain of Oct-2 can efficiently repress all types of activation domains. This effect is observed however, only on TATA box-containing promoters and not on promoters containing an initiator motif. This widespread inhibition of different activation domains and its dependence on the nature of the basal promoter elements indicate that the inhibitory domain is likely to act by contacting a common downstream target of activation domains within the basal transcriptional complex bound at the TATA box rather than quenching specific activation domains by direct interaction. These effects are discussed in terms of the functional role of the inhibitory domain within Oct-2.5 and the mechanism by which it acts.
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Affiliation(s)
- Y Z Liu
- Department of Molecular Pathology, University College London Medical School, London W1P 6DB, United Kingdom
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23
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Abstract
The p16INK4 tumor-suppressor gene (also known as CDKN2, CDK41 and MTS1) encodes a negative regulator of the cell cycle. This gene, located in 9p21, is mutated or homozygously deleted in a high percentage of tumor cell lines and specific types of primary tumors. We have examined the status of the p16INK4 gene in 31 thyroid tumors and 7 thyroid cell lines. No DNA abnormalities were found in primary tumors. Conversely, p16INK4 gene structural alterations, deletions and point mutations were found in 4 thyroid cell lines. The expression of the 2 different p16INK4 mRNAs, the p16alpha and p16beta transcripts, was determined by RNA-PCR experiments. All the primary thyroid tumors expressed the beta transcript, while the p16alpha was barely detectable. The thyroid cell lines always expressed the p16beta transcript, while the alpha transcript was absent or, whenever present, coded for a mutated form of the p16INK4 gene product. Taken together, our results suggest that loss of p16INK4 function is not directly involved in the process of thyroid-tumor development, but it probably gives cells in tissue culture a selective growth advantage.
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Affiliation(s)
- V Calabrò
- Dipartimento di Genetica, Biologia Generale e Molecolare, Università Federico II, Naples, Italy
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24
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Abstract
Sp3 is a member of the Sp family of transcription factors, and it binds to the GC box with an affinity and specificity comparable with that of Sp1. Previous studies have shown that Sp3 repressed Sp1-mediated transcriptional activation, suggesting that Sp3 is an inhibitory member of the Sp family. The experiments described here demonstrate that Sp3 contains a portable repression domain that can function independently from the zinc finger DNA-binding domain. We found that the amino-terminal region of Sp3 tethered to a promoter DNA by connecting to a heterologous DNA-binding protein domain represses transcriptional activation by different positive regulators. Moreover, we determined that Sp3 targeted to a promoter-proximal RNA sequence acts as a transcriptional repressor. Taken together, our results suggest that Sp3 functions as a repressor by protein-protein interaction with components of the general transcription complex.
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Affiliation(s)
- P De Luca
- Department of Genetics, Molecular and General Biology, University of Naples "Federico II," via Mezzocannone 8, 80134 Naples, Italy. 10
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25
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Pengue G, Lania L. Krüppel-associated box-mediated repression of RNA polymerase II promoters is influenced by the arrangement of basal promoter elements. Proc Natl Acad Sci U S A 1996; 93:1015-20. [PMID: 8577706 PMCID: PMC40022 DOI: 10.1073/pnas.93.3.1015] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The evolutionarily conserved Krüppel-associated box (KRAB) is present in the N-terminal regions of more than one-third of all Krüppel-class zinc finger proteins. Recent experiments have demonstrated that the KRAB-A domain tethered to a promoter DNA by connecting to heterologous DNA-binding protein domain or targeted to a promoter-proximal RNA sequence acts as a transcriptional silencing of RNA polymerase II promoters. Here we show that expression of KRAB domain suppresses in vivo the activating function of various defined activating transcription factors, and we demonstrate that the KRAB domain specifically silences the activity of promoters whose initiation is dependent on the presence of a TATA box. Promoters whose accurate transcription initiation is directed by a pyrimidine-rich initiator element, however, are relatively unaffected. We also report in vitro transcription experiments indicating that the KRAB domain is able to repress both activated and basal promoter activity. Thus, the KRAB domain appears to repress the activity of certain promoters through direct communication with TATA box-dependent basal transcription machinery.
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Affiliation(s)
- G Pengue
- Department of Genetics, Molecular and General Biology, University of Naples, Federico II, Italy
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26
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Pengue G, Caputo A, Rossi C, Barbanti-Brodano G, Lania L. Transcriptional silencing of human immunodeficiency virus type 1 long terminal repeat-driven gene expression by the Krüppel-associated box repressor domain targeted to the transactivating response element. J Virol 1995; 69:6577-80. [PMID: 7666562 PMCID: PMC189563 DOI: 10.1128/jvi.69.10.6577-6580.1995] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The evolutionarily conserved protein domain, called the Krüppel-associated box (KRAB), present in the amino termini of a large number of Krüppel-type zinc finger proteins is a strong repressor domain. In order to develop novel strategies to control human immunodeficiency virus type 1 (HIV-1) gene expression, we constructed a series of expression vectors expressing the wild-type Tat or Tat transdominant negative mutants fused to the KRAB repressor domain. We found that the KRAB domain tethered to the transactivating response element is able to suppress both basal and Tat-mediated activity of HIV-1 long terminal repeat-driven gene expression. These results suggest that the KRAB repressor domain fused to the Tat transdominant negative mutants can be successfully employed to control HIV-1 gene expression.
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Affiliation(s)
- G Pengue
- Department of Genetics, Molecular and General Biology, University of Naples, Federico II, Italy
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27
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Majello B, De Luca P, Suske G, Lania L. Differential transcriptional regulation of c-myc promoter through the same DNA binding sites targeted by Sp1-like proteins. Oncogene 1995; 10:1841-8. [PMID: 7753559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Sp1 and Sp3 are closely related members of a gene family encoding proteins with very similar structural features. The zinc finger DNA binding domains of Sp1 and Sp3 are highly conserved and they bind to GC and GT box with comparable affinities. To begin to delineate the specific roles of these two members of the Sp1-like gene family, here we have analysed the DNA binding specificity and their effects on activation of human c-myc promoter. We found that both proteins bind to the same sites of c-myc promoter, upstream to both the P1 and P2 initiation sites. Cotransfection experiments, in mammalian and insect cells, indicated that Sp1 trans-activate c-myc promoter, whereas Sp3 did not. In addition, enforced expression of Sp3 repressed Sp1-mediated activation of c-myc. Finally, we found that Sp1 and E2F-1/DP-1 cooperatively trans-activate c-myc promoter. In contrast enforced expression of Sp3 fails to repress E2F-1/DP-1-mediated activation.
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Affiliation(s)
- B Majello
- Dipartimento di Genetica, Biologia Generale e Molecolare, Università Federico II, Naples, Italy
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28
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Pagliuca A, Bartoli PC, Saccone S, Della Valle G, Lania L. Molecular cloning of ID4, a novel dominant negative helix-loop-helix human gene on chromosome 6p21.3-p22. Genomics 1995; 27:200-3. [PMID: 7665172 DOI: 10.1006/geno.1995.1026] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Transcription factors containing a basic helix-loop-helix (bHLH) motif regulate the expression of tissue-specific genes in a number of mammalian and insect systems. DNA-binding activity of the bHLH proteins is dependent upon formation of homo- and/or heterodimers. Dominant negative HLH proteins (Id-related genes) also contain the HLH-dimerization domain but lack the DNA-binding basic domain. Consequently, Id proteins inhibit binding to DNA and transcriptional transactivation by heterodimerization with bHLH proteins. We report here the cDNA sequence of a novel human HLH gene (HGMW-approved symbol ID4) that lacks the basic domain. ID4 is differentially expressed in adult organs in four mRNA molecules, which are presumably a result of differential splicing and/or alternative usage of the polyadenylation sites. Transfection experiments indicated that enforced expression of Id-4H protein inhibits the trans-activation of the muscle creatine kinase E-box enhancer by MyoD. Finally, we localized the ID4 gene to the chromosome 6p21-p22 region.
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Affiliation(s)
- A Pagliuca
- Dipartimento di Genetica, Biologia Generale e Molecolare, Università Federico II, Via Mezzocannone 8, Naples, Italy
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29
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Calabrò V, Pengue G, Bartoli PC, Pagliuca A, Featherstone T, Lania L. Positional cloning of cDNAs from the human chromosome 3p21-22 region identifies a clustered organization of zinc-finger genes. Hum Genet 1995; 95:18-21. [PMID: 7814019 DOI: 10.1007/bf00225067] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The human 3p21-22 region is frequently involved in karyotype rearrangements associated with malignancies. The high frequency of allelic loss in this region has been associated with virtually all small cell lung carcinomas and many renal carcinomas. These findings suggest that at least one tumor-suppressor gene might be located in 3p21-22. We have recently reported the isolation of a 750-kb yeast artificial chromosome (YAC) contig from 3p21-22. Here, we describe three new genes isolated from the 3p YAC contig by using a cDNA hybridization selection. Remarkably, the three new genes encode zinc-finger proteins, indicating the presence of a cluster of zinc-finger genes in human chromosome 3p21.
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Affiliation(s)
- V Calabrò
- Dipartimento di Genetica, Università Federico II, Naples, Italy
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30
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Majello B, De Luca P, Hagen G, Suske G, Lania L. Different members of the Sp1 multigene family exert opposite transcriptional regulation of the long terminal repeat of HIV-1. Nucleic Acids Res 1994; 22:4914-21. [PMID: 7800480 PMCID: PMC523756 DOI: 10.1093/nar/22.23.4914] [Citation(s) in RCA: 197] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Recently, a family of transcription factors structurally related to Sp1 has been described; thus, more than one activator may bind to the GC boxes present in a number of viral and cellular promoters. We have compared the transactivation potentials of Sp1, Sp3 and Sp4 proteins on the human immunodeficiency virus type 1 (HIV-1) promoter. The long terminal repeat (LTR) of HIV-1 contains three binding sites for the transcription factor Sp1 (GC boxes) which are involved in both basal and Tat-mediated transcriptional activation. Moreover, a cooperative interaction between NF-kappa B and Sp1 is required for HIV enhancer activation. We now demonstrate that Sp4 is an activator, while the Sp3 protein represses basal expression of HIV promoter. Remarkably, we found that over-expression of the transcription factor Sp3 was able to suppress Tat-mediated transactivation. These inhibitory effects of Sp3 correlate with its DNA binding activity, suggesting that Sp3 inhibition involves competition with Sp1 for occupancy of the GC boxes. Next, we have analyzed the role of different Sp1-related proteins in the stimulation of HIV-1 promoter in response to mitogens. We found that the binding of NF-kappa B is not by itself sufficient to induce HIV gene expression. Instead, an interaction between NF-kappa B and the trans-acting domain (A domain) of Sp1 bound to an adjacent site must occur. We found that the cooperative interaction between NF-kappa B and Sp1 is highly specific, since neither Sp3 nor Sp4 is capable of cooperating with NF-kappa B.
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Affiliation(s)
- B Majello
- Dipartimento di Genetica, Biologia Generale e Molecolare, Università Federico II, Naples, Italy
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31
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Pengue G, Calabrò V, Bartoli PC, Pagliuca A, Lania L. Repression of transcriptional activity at a distance by the evolutionarily conserved KRAB domain present in a subfamily of zinc finger proteins. Nucleic Acids Res 1994; 22:2908-14. [PMID: 8065901 PMCID: PMC310254 DOI: 10.1093/nar/22.15.2908] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Sub-families of related zinc finger protein genes have been defined on the basis of evolutionarily conserved structural features found outside the C2-H2 finger repeats. Such elements include the FAX domain found in a large number of Xenopus ZFPs, the evolutionarily conserved KRAB (Krüppel-associated box) and the ZiN (zinc finger N-terminal) domains. Here we describe a new evolutionarily conserved motif within zinc finger proteins which we have named the leucine rich region (LeR). Since conserved modules in regulatory proteins may specify properties relevant to their action we have determined the functional capabilities of LeR and the KRAB domains in the regulation of gene transcription by fusing relevant regions to a heterologous DNA-binding domain (GAL4 DNA-binding domain). We found that the KRAB-A domain tethered to RNA polymerase II promoters by a GAL4 DNA-binding domain actively represses transcription in a distance-independent manner. KRAB-mediated repression is dependent on the dose of the GAL4-KRAB-A fusion protein and on the presence of GAL4 binding sites on the DNA. Conversely, the LeR domain did not modulate significantly the transcription. Our results indicate that the KRAB domain present in the non-finger region of many ZFP genes quenches transcription possibly due to specific protein-protein interactions between the KRAB-A domain and components of the proximal transcriptional apparatus.
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Affiliation(s)
- G Pengue
- Dipartimento di Genetica, Biologia Generale e Molecolare, Università Feredico II, Naples, Italy
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32
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Abstract
ERV9 is a low repeated family of human endogenous retroviral elements whose expression is mainly detectable in undifferentiated embryonal carcinoma NT2/D1 cells. To define all the elements required for the correct transcription activity of the ERV9 promoter and to establish a precise correlation between the elements important for basal transcription, we have systematically analyzed the in vivo and in vitro transcriptional activity of many different ERV9 promoter mutants, including a series of linker-scanning mutations across the promoter region. We report here that the ERV9 promoter contains two elements controlling the selection of the correct start sites, a TATA box and an Inr-like region; the concerted action of both elements is necessary for faithful transcription. Finally, using a series of GAL4 protein fusion constructs in cotransfection experiments, we demonstrated that various transcription factors can synergistically induce a high level of transcription when bound to an ERV9 DNA promoter.
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Affiliation(s)
- M Strazzullo
- Department of Genetics, General and Molecular Biology, University of Naples, Italy
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33
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Abstract
We developed a rapid method to determine DNA-binding sites for putative DNA-binding proteins. This procedure has been successfully used to define a specific consensus site for the human ZNF35 zinc finger gene. ZNF35 encodes a 58-kDA polypeptide containing 11 consecutive finger motifs located at the amino terminus, and an acidic domain located at the carboxy terminus. These features suggest that ZNF35 is a site-specific DNA-binding protein involved in the regulation of gene expression. We have expressed the ZNF35 protein from E. coli and have employed a Southwestern-polymerase chain reaction method using random oligonucleotides to identify its high-affinity binding site. The core sequence for the ZNF35 protein-binding site is 5'-C/GC/GAAG/TA-3'.
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Affiliation(s)
- G Pengue
- Dipartimento di Genetica, Biologia Generale e Molecolare, University of Naples, Italy
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34
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Lania L, Di Cristofano A, Strazzullo M, Pengue G, Majello B, La Mantia G. Structural and functional organization of the human endogenous retroviral ERV9 sequences. Virology 1992; 191:464-8. [PMID: 1413518 DOI: 10.1016/0042-6822(92)90211-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The human genome contains a variety of genetic elements similar in structure to retroviruses and retrotransposons. We report here the structural and functional organization of a novel human endogenous retroviral family (ERV9). Three polyadenylated RNAs, 8, 2, and 1.5 kb long, are detected by Northern blot in undifferentiated embryonal carcinoma NT2/D1 cells. Upon genomic cloning of an expressed ERV9 locus, we demonstrated that the three polyadenylated RNAs are originated by a single ERV9 locus by alternative usage of splicing and polyadenylation signals. DNA sequence analysis of different ERV9 LTRs have revealed that they are heterogeneous in length and that the length variability is due to the number of tandemly repeated subelements present in both U3 and U5 regions; moreover, the ERV9 LTRs are capable to drive expression of a reporter gene in transient expression assays. Finally, analysis of the ERV9 5' transcription start site has allowed us to define the U3-R-U5 organization of the ERV9 LTR.
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Affiliation(s)
- L Lania
- Dipartimento di Genetica, Biologia Generale e Molecolare University of Naples, Italy
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35
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La Mantia G, Majello B, Di Cristofano A, Strazzullo M, Minchiotti G, Lania L. Identification of regulatory elements within the minimal promoter region of the human endogenous ERV9 proviruses: accurate transcription initiation is controlled by an Inr-like element. Nucleic Acids Res 1992; 20:4129-36. [PMID: 1508707 PMCID: PMC334116 DOI: 10.1093/nar/20.16.4129] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
ERV9 is a low repeated family of human endogenous retroviral elements whose expression is mainly detectable in undifferentiated embryonal carcinoma NT2/D1 cells. In this report we have analyzed the minimal promoter region located within the ERV9 LTR. Using the transient CAT expression assay we have identified the minimal promoter region, which includes sequences spanning from -70 to +6 relative to the major transcription start site. Deletion analysis, primer extension mapping of the transcription start sites and DNA-protein interactions assays have allowed us to define two important regions within the ERV9 minimal promoter. One region located between -70 to -39 acts as a transcriptional activating sequence and contains an Sp 1 binding site. The second region from -7 to +6, which resembles an initiator element (Inr), was necessary for the correct transcription start site utilization, and binds to a regulatory protein. Cross-competition experiments using various Inr elements have indicated that the protein that binds to the ERV9 Inr element can be competed by the HIV-1 and TdT Inr sequences.
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Affiliation(s)
- G La Mantia
- Department of Genetics, University of Naples, Italy
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36
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La Mantia G, Maglione D, Pengue G, Di Cristofano A, Simeone A, Lanfrancone L, Lania L. Identification and characterization of novel human endogenous retroviral sequences prefentially expressed in undifferentiated embryonal carcinoma cells. Nucleic Acids Res 1991; 19:1513-20. [PMID: 2027759 PMCID: PMC333909 DOI: 10.1093/nar/19.7.1513] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A novel endogenous retroviral sequence (ERV-9) has been isolated from a human embryonal carcinoma cDNA library by hybridization to a probe containing a recently described human repetitive element. DNA sequence analysis of the 4kb cDNA insert (pHE.1) revealed the presence of ORFs potentially coding for putative retrovirus-related gag, pol and env proteins. Northern blot and RNase protection experiments showed that RNA homologous to the pHE.1 insert is detected only in embryonal carcinoma cells as a 8 kb mRNA, and its expression is negatively regulated during retinoic acid induced differentiation of the human teratocarcinoma cell line NT2/D1. Using a pol specific probe we have isolated a genomic locus containing the ERV-9 sequences. Characterization by restriction enzyme analysis and DNA sequencing allowed us to define LTR-like sequences, that are composed by a complex array of subrepetitive elements. In addition we show that ERV-9 LTR sequences are capable to drive expression of linked CAT gene in a cell specific manner as LTR promoter activity has been detected only in NT2/D1 cells.
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MESH Headings
- Amino Acid Sequence
- Base Sequence
- Blotting, Southern
- DNA, Neoplasm/analysis
- DNA, Neoplasm/genetics
- DNA, Viral/analysis
- DNA, Viral/genetics
- Embryonal Carcinoma Stem Cells
- Genes, Viral
- Humans
- Molecular Sequence Data
- Neoplastic Stem Cells/metabolism
- Open Reading Frames
- Plasmids
- Promoter Regions, Genetic
- RNA, Neoplasm/analysis
- RNA, Neoplasm/genetics
- RNA, Viral/analysis
- RNA, Viral/genetics
- Restriction Mapping
- Retroviridae/genetics
- Sequence Alignment
- Tumor Cells, Cultured
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Affiliation(s)
- G La Mantia
- Department of Genetics, General and Molecular Biology, University of Naples, Italy
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37
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Donti E, Lanfrancone L, Huebner K, Pascucci A, Venti G, Pengue G, Grignani F, Croce CM, Lania L, Pelicci PG. Localization of the human HF.10 finger gene on a chromosome region (3p21-22) frequently deleted in human cancers. Hum Genet 1990; 84:391-5. [PMID: 2108922 DOI: 10.1007/bf00195806] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The finger motif is a tandemly repeated DNA-binding domain recently identified in the primary structure of several eukaryotic transcriptional regulatory proteins. It has been proposed that some members of the finger-gene family are implicated in both normal cell proliferation and differentiation. We isolated several human finger genes by means of hybridization with a finger motif-containing DNA probe. One of these finger genes, HF.10, is expressed at low levels in a variety of human tissues and is down-regulated during the in vitro terminal differentiation of human leukemic myeloid cell lines. By in situ hybridization experiments and analysis of interspecific somatic cell hybrids we mapped the HF.10 gene to 3p21-22, a chromosome region frequently involved in karyotypic rearrangements associated with lung and renal cancer.
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Affiliation(s)
- E Donti
- Istituto di Clinica Medica I, Policlinico Monteluce, Università di Perugia, Italy
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38
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Lania L, Donti E, Pannuti A, Pascucci A, Pengue G, Feliciello I, La Mantia G, Lanfrancone L, Pelicci PG. cDNA isolation, expression analysis, and chromosomal localization of two human zinc finger genes. Genomics 1990; 6:333-40. [PMID: 2106481 DOI: 10.1016/0888-7543(90)90574-e] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
On the basis of sequence similarity in the repeated zinc finger domain, we have identified and characterized two human cDNA clones (ZNF7 and ZNF8), both encoding proteins containing potential finger-like nucleic acid binding motifs. Northern blot analysis indicates that both genes are expressed as multiple transcripts and they are ubiquitously present in many human cell lines of different embryological derivation. Moreover, their expression is modulated during in vitro induced terminal differentiation of human myeloid cell line HL-60. By in situ hybridization experiments, we have localized the ZNF7 gene to chromosome 8 (region q24) and the ZNF8 gene to the terminal band of the long arm of chromosome 20 (20q13).
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Affiliation(s)
- L Lania
- Department of Genetics, University of Naples, Italy
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39
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La Mantia G, Pengue G, Maglione D, Pannuti A, Pascucci A, Lania L. Identification of new human repetitive sequences: characterization of the corresponding cDNAs and their expression in embryonal carcinoma cells. Nucleic Acids Res 1989; 17:5913-22. [PMID: 2475853 PMCID: PMC318249 DOI: 10.1093/nar/17.15.5913] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We have identified new repeated interspersed DNA sequences by analysis of homologous RNA transcripts from a human teratocarcinoma cell line (NTERA-2 clone D1). The abundance of transcripts varies upon retinoic acid induced differentiation of NTERA-2/D1 cells, and it is highest when the cells display the embryonal carcinoma phenotype. The expression of these novel repeated sequences appears to be tissue specific as no detectable expression was found in various cell lines of different embryological derivation. Characterization of the RNA transcripts by analysis of recombinant cDNA clones indicated that transcripts of different genomic units are present in undifferentiated embryonal teratocarcinoma cells. Nucleotide sequencing of the cloned cDNAs reveals a complex structure composed by unique and tandemly repeated sub-elements.
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Affiliation(s)
- G La Mantia
- Dipartimento di Genetica, Biologia Generale e Molecolare, University of Naples, Italy
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40
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Pannuti A, Lanfrancone L, Pascucci A, Pelicci PG, La Mantia G, Lania L. Isolation of cDNAs encoding finger proteins and measurement of the corresponding mRNA levels during myeloid terminal differentiation. Nucleic Acids Res 1988; 16:4227-37. [PMID: 3380682 PMCID: PMC336626 DOI: 10.1093/nar/16.10.4227] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The finger motif is a tandemly repeated DNA-binding domain recently identified in the primary structure of several eukaryotic transcriptional regulatory proteins. It was first described for Xenopus TFIIIA, a factor required for transcription of 5S ribosomal genes and subsequently identified in regulatory proteins from other eukaryotic organisms including yeast, Drosophila and mammals. In this paper we report the isolation and characterization of two human cDNA clones both encoding for multifingered protein products. Transcriptional studies indicate that the two finger genes are expressed in a variety of human tissues. Moreover, upon in vitro induced terminal differentiation of human HL-60 and THP-1 myeloid cell lines the expression of both genes is drastically reduced. These data provide support for the existence of a human multigene family coding for regulatory finger proteins which are likely involved in the processes of cell differentiation and/or proliferation.
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Affiliation(s)
- A Pannuti
- Dipartimento di Genetica, Biologia Generale e Molecolare, University of Naples, Italy
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41
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Pascucci A, Pannuti A, La Mantia G, Lania L. Sequences both 5' and 3' to the transcription initiation site contribute to the ability of a mouse H-2 gene to respond to type I interferon. FEBS Lett 1988; 226:297-302. [PMID: 3338560 DOI: 10.1016/0014-5793(88)81443-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
To investigate the cis-acting DNA elements that are involved in the regulation of class I major histocompatibility complex genes by interferon, several promoter fragments of the H-2Kk gene were linked to the reporter chloramphenicol acetyl transferase (CAT) gene, and the CAT expression was analyzed in stable transfected cell lines. The functional activities of progressive deletions of the 5'-flanking region of the H-2Kk gene linked to the CAT gene have allowed us to define a discrete cis-acting DNA region necessary for interferon-mediated stimulation. Moreover, the H-2Kk gene transcribed by the nonregulated SV40 early promoter was also found to be under interferon regulation. Thus interferon enhancement of the H-2Kk gene expression appears to be mediated by two cis-acting elements, one located in the 5'-flanking region and the other by sequences downstream from the transcription initiation site.
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Affiliation(s)
- A Pascucci
- Dipartimento di Genetica, Biologia Generale e Molecolare, University of Naples, Italy
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Ruley HE, Chaudry F, Read M, Lania L, Fried M. The structure and function of the integrated polyoma virus DNA in 82-rat and 53-rat transformed cells. J Gen Virol 1988; 69 ( Pt 1):197-207. [PMID: 2826666 DOI: 10.1099/0022-1317-69-1-197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Integrated viral sequences and adjacent cellular sequences from the polyoma virus (Py)-transformed 53-Rat and 82-Rat cell lines which contain two and three partial early regions respectively, each in a single viral insert, have been molecularly cloned. Each of the cloned partial early regions have been subcloned and assessed with regard to their transcription, translation products (T antigens, T Ags) and biological activity including their transforming ability. The 53-Rat 5.3 kb EcoRI fragment is an intact Py EcoRI linear genome (derived from within the tandem duplicated sequences) which transforms rat cells with high efficiency and produces infectious virus when circularized and transfected into mouse cells. The 82-Rat cell line expresses three novel T Ag species of 63K, 40K and 32K in addition to the Py middle and small T Ags. The 63K protein was found to be a truncated form of large T Ag produced as the result of an addition/deletion in early region B sequences unique to large T Ag. The 40K and 32K proteins are hybrid viral-cellular middle and large T Ags respectively, which are expressed from early region A that has been truncated by recombination with rat cellular DNA. Differences in the nuclear and cytoplasmic location of the different 82-Rat early region RNAs are due to RNA stability and/or transport from the nucleus to the cytoplasm most likely as a result of different cellular sequences at their 3' ends. Finally no common structural feature or sequence specificity was observed at the virus-host DNA joins of the two cell lines.
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Affiliation(s)
- H E Ruley
- Department of Tumour Genetics, Imperial Cancer Research Fund, Lincoln's Inn Fields, London, U.K
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Lania L, Pannuti A, La Mantia G, Basilico C. The transcription of B2 repeated sequences is regulated during the transition from quiescent to proliferative state in cultured rodent cells. FEBS Lett 1987; 219:400-4. [PMID: 3609298 DOI: 10.1016/0014-5793(87)80260-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The RNA polymerase III-dependent transcription of B2 repeated sequences has been monitored during the transition from the quiescent to proliferative state in cultured rodent cells and after polyomavirus-induced transformation. The level of RNAs containing B2 sequences was found to be higher in both the proliferative state of normal cells and in polyomavirus-transformed cells. In both systems, nuclear run-off transcription assays indicated that high levels of B2 RNAs are due to an enhanced transcription rate. These results suggest the presence of a B2-specific RNA pol III transcription factor(s) whose activity is sensitive to cell cycle progression and oncogenic transformation.
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Pannuti A, Pascucci A, La Mantia G, Fisher-Fantuzzi L, Vesco C, Lania L. trans-activation of cellular and viral promoters by a transforming nonkaryophilic simian virus 40 large T antigen. J Virol 1987; 61:1296-9. [PMID: 3029428 PMCID: PMC254098 DOI: 10.1128/jvi.61.4.1296-1299.1987] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We used the chloramphenicol acetyl transferase (CAT) transient expression system to study the transactivating ability of a simian virus 40 (SV40) mutant that was unable to transport and localize large T antigen into the nucleus and which retained the competence to transform established cell lines. The effect of the SV40 wild type and the SV40 mutant for the large T antigen was tested in both mouse and simian cells on a series of plasmids in which the CAT gene was regulated by one of the following promoters: SV40 early and late, herpes simplex virus thymidine kinase, chicken alpha 2(I) collagen, mouse H-2Kk. Our results indicated that both the SV40 wild type and the cytoplasmic mutant for the large T antigen regulated transcription from any promoter tested, suggesting that the trans-activation by SV40 does not require the nuclear localization of the 100,000-molecular-weight large T-antigen protein.
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MESH Headings
- Animals
- Antigens, Polyomavirus Transforming
- Antigens, Viral, Tumor/genetics
- Antigens, Viral, Tumor/metabolism
- Cell Line
- Cell Transformation, Viral
- Cells, Cultured
- Genes, Viral
- Mutation
- Oncogene Proteins, Viral/genetics
- Oncogene Proteins, Viral/metabolism
- Promoter Regions, Genetic
- Protein Kinases/metabolism
- Simian virus 40/genetics
- Virus Activation
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Abstract
The chloramphenicol-acetyl-transferase (CAT) expression system has been utilized to study the ability of the polyomavirus (Py) early proteins, the 100K large T, the 55K middle T and 22K small T-antigens, to activate a variety of eukaryotic promoters (the SV40 early, the alpha 2(1) collagen, the rabbit beta-globin, the polyomavirus early and the H-2 class I) in both transient and stable expression assays. We have found that either the complete polyomavirus early region or a plasmid expressing only the 55K middle T-antigen are capable of stimulating the expression of all the promoter-CAT plasmids in transient co-transfection experiments in both NIH-3T3 and Rat-2 cells. Conversely, the Py early proteins do not stimulate the transcription of most of the promoter-CAT genes stably introduced in the cell chromosomes, with the exception of H-2 class I promoter, when stimulation of transcription has been observed upon infection with recombinant retrovirus encoding the Py middle T-antigen.
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Abstract
The structural and biological properties of a polyomavirus mutant selected in Friend erythroleukemic cells were investigated. The growth efficiency of this mutant (PyFL78) was compared with that of the parental PyA2 strain by a growth competition assay in Friend erythroleukemic and 3T3 (or 3T6) cell lines. The results reveal that PyFL78 displays a cis-acting growth advantage over the PyA2 parental strain in Friend erythroleukemic cells but not in 3T3 or 3T6 cells. This cell-specific cis advantage is shown to be due to modifications within the polyomavirus noncoding regulatory region.
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Majello B, La Mantia G, Simeone A, Boncinelli E, Lania L. Activation of major histocompatibility complex class I mRNA containing an Alu-like repeat in polyoma virus-transformed rat cells. Nature 1985; 314:457-9. [PMID: 2984576 DOI: 10.1038/314457a0] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Class I genes of the major histocompatibility complex (MHC) appear to be activated in mouse cells transformed by the DNA tumour virus simian virus 40 (SV40). Conversely, suppression of MHC class I genes has been reported in adenovirus-12-transformed baby kidney rat cells. We have now investigated the expression of genes encoded by the rat MHC locus in rat fibroblast cells transformed by polyoma virus (Py). Using a mouse genomic H-2 clone as a probe in Northern transfer hybridization analysis, we have observed a high level of expression of rat MHC class I messenger RNA in all the transformed rat cell lines analysed. The class I 1.6-kilobase (kb) mRNA activated in Py-transformed rat cells appears to contain an Alu-like type II repeat element, as the same 1.6-kb mRNA is detected using either the H-2 class I sequence or a repetitive Alu-like type II element as a probe. High levels of heterogeneous poly(A)+ transcripts of 0.5-0.8 kb are also observed in Py-transformed rat cells using probes containing an Alu-like type II repetitive element.
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Abstract
Human fibroblasts (HF) were transformed in vitro with origin-defective SV40 DNA (ori-) using the calcium phosphate co-precipitation technique. The SV40 ori- transformed human cells (HSF) were able to replicate efficiently a recombinant DNA molecule containing the ori sequence of SV40 DNA. Transfection of HFS with pTBC1, a recombinant pi vx plasmid containing the herpes simplex virus thymidine kinase (HSV-TK) gene and the ori SV40 sequences, results in high levels of TK mRNA of correct size. The pTBC1 plasmid does not appear to contain 'poison' sequences and can be efficiently re-established in Escherichia coli after replication in human cells. This host vector system may be of great usefulness in studying the expression of human genes in human cells.
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Fried M, Griffiths M, Davies B, Bjursell G, La Mantia G, Lania L. Isolation of cellular DNA sequences that allow expression of adjacent genes. Proc Natl Acad Sci U S A 1983; 80:2117-21. [PMID: 6300895 PMCID: PMC393768 DOI: 10.1073/pnas.80.8.2117] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We have employed a strategy for the isolation and identification of cellular control (expression) sequences dependent on their ability to confer expression on a selectable gene devoid of its own expression sequences. The polyoma virus (Py) Hae II-BamHI DNA fragment, which comprises 84% of the intact viral DNA and contains the Py transforming region but lacks Py 5' expression sequences, was decreased markedly in its transformation of rat cells. Hae II-cleaved mouse cellular DNA was ligated to the Py Hae II-BamHI fragment. A transformed colony (H1) isolated after transfection of the ligated DNA onto rat cells was found to contain multiple inserts of Py DNA, most of which were biologically inactive. A transformed colony (H2) isolated after transfection of rat cells with total H1 DNA was found to contain a single insert of Py DNA. The H2 cells are highly tumorigenic and synthesize the three Py tumor antigens. Initiation of transcription of the Py early mRNAs in H2 cells occurs at the same Py nucleotides as in complete Py DNA. The viral and adjacent cellular DNA sequences were cloned from H2 cellular DNA. The transforming efficiency of the cloned Py transforming region and adjacent H2 cellular DNA was 20-40% of that of the viral DNA containing Py expression sequences. By BAL-31 deletion mapping it was observed that the first 58 base pairs of H2 cellular DNA were sufficient for the expression of the Py-transforming region. The sequence of the first 149 base pairs of the H2 cellular DNA was determined and does not show any striking similarities to upstream 5' sequences of a number of viral and host structural genes. Features of the H2 cellular sequence are discussed.
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Ruley HE, Lania L, Chaudry F, Fried M. Use of a cellular polyadenylation signal by viral transcripts in polyoma virus transformed cells. Nucleic Acids Res 1982; 10:4515-24. [PMID: 6290990 PMCID: PMC321108 DOI: 10.1093/nar/10.15.4515] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The DNA sequences at and around the junctions between viral and cellular DNA in the polyoma virus transformed mouse cell line, TS-A-3T3, have been determined. No common sequence specificity or structural features at the joins have been observed. The sequence indicates that the 94K truncated large T antigen found in TS-A-3T3 cells is a hybrid protein in which the carboxy-terminal 19 amino acids are encoded by adjacent host sequences. Moreover, the three early region transcripts initiated in viral sequences are also hybrid in nature and appear to utilize a host polyadenylation signal associated with the hexanucleotide, AATAAA, found 100 bp beyond a viral-host join.
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