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Lan S, Östberg S, Punga T, Akusjärvi G. A suppressive effect of Sp1 recruitment to the first leader 5' splice site region on L4-22K-mediated activation of the adenovirus major late promoter. Virus Res 2015; 210:133-40. [PMID: 26247419 DOI: 10.1016/j.virusres.2015.07.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 07/23/2015] [Accepted: 07/28/2015] [Indexed: 11/16/2022]
Abstract
Transcription from the adenovirus major late promoter (MLP) requires binding of late phase-specific factors to the so-called DE element located approximately 100 base pairs downstream of the MLP transcriptional start site. The adenovirus L4-22K protein binds to the DE element and stimulates transcription from the MLP via a DE sequence-dependent mechanism. Here we use a transient expression approach to show that L4-22K binds to an additional site downstream of the MLP start site, the so-called R1 region, which includes the major late first leader 5' splice site. Binding of L4-22K to R1 has a suppressive effect on MLP transcription. L4-22K binds to the distal part of R1 and stimulates the recruitment of Sp1 and other cellular factors to a site overlapping the first leader 5' splice site. Binding of Sp1 to the 5' splice site region had an inhibitory effect on L4-22K-activated MLP transcription.
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Affiliation(s)
- Susan Lan
- Department of Medical Biochemistry and Microbiology, Uppsala Biomedical Center, Uppsala University, S-751 23 Uppsala, Sweden.
| | - Sara Östberg
- Department of Medical Biochemistry and Microbiology, Uppsala Biomedical Center, Uppsala University, S-751 23 Uppsala, Sweden.
| | - Tanel Punga
- Department of Medical Biochemistry and Microbiology, Uppsala Biomedical Center, Uppsala University, S-751 23 Uppsala, Sweden.
| | - Göran Akusjärvi
- Department of Medical Biochemistry and Microbiology, Uppsala Biomedical Center, Uppsala University, S-751 23 Uppsala, Sweden.
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2
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Cherubini G, Naim V, Caruso P, Burla R, Bogliolo M, Cundari E, Benihoud K, Saggio I, Rosselli F. The FANC pathway is activated by adenovirus infection and promotes viral replication-dependent recombination. Nucleic Acids Res 2011; 39:5459-73. [PMID: 21421559 PMCID: PMC3141233 DOI: 10.1093/nar/gkr084] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Deciphering the crosstalk between a host cell and a virus during infection is important not only to better define viral biology but also to improve our understanding of cellular processes. We identified the FANC pathway as a helper of viral replication and recombination by searching for cellular targets that are modified by adenovirus (Ad) infection and are involved in its outcome. This pathway, which is involved in the DNA damage response and checkpoint control, is altered in Fanconi anaemia, a rare cancer predisposition syndrome. We show here that Ad5 infection activates the FANC pathway independent of the classical DNA damage response. Infection with a non-replicating Ad shows that the presence of viral DNA is not sufficient to induce the monoubiquitination of FANCD2 but still activates the DNA damage response coordinated by phospho-NBS1 and phospho-CHK1. E1A expression alone fails to induce FANCD2 monoubiquitination, indicating that a productive viral infection and/or replication is required for FANC pathway activation. Our data indicate that Ad5 infection induces FANCD2 activation to promote its own replication. Specifically, we show that FANCD2 is involved in the recombination process that accompanies viral DNA replication. This study provides evidence of a DNA damage-independent function of the FANC pathway and identifies a cellular system involved in Ad5 recombination.
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Affiliation(s)
- Gioia Cherubini
- University Paris-Sud, UMR8200 CNRS, Institute Gustave Roussy, Villejuif, France
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3
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Ali H, LeRoy G, Bridge G, Flint SJ. The adenovirus L4 33-kilodalton protein binds to intragenic sequences of the major late promoter required for late phase-specific stimulation of transcription. J Virol 2006; 81:1327-38. [PMID: 17093188 PMCID: PMC1797539 DOI: 10.1128/jvi.01584-06] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The adenovirus late IVa2 protein is required for maximally efficient transcription from the viral major late (ML) promoter, and hence, the synthesis of the majority of viral late proteins. This protein is a sequence-specific DNA-binding protein that also promotes the assembly of progeny virus particles. Previous studies have established that a IVa2 protein dimer (DEF-B) binds specifically to an intragenic ML promoter sequence necessary for late phase-specific stimulation of ML transcription. However, activation of transcription from the ML promoter correlates with binding of at least one additional infected-cell-specific protein, termed DEF-A, to the promoter. Using an assay for the DNA-binding activity of DEF-A, we identified the unknown protein by using conventional purification methods, purification of FLAG-tagged IVa2-protein-containing complexes, and transient synthesis of viral late proteins. The results of these experiments established that the viral L4 33-kDa protein is the only component of DEF-A: the IVa2 and L4 33-kDa proteins are necessary and sufficient for formation of all previously described complexes in the intragenic control region of the ML promoter. Furthermore, the L4 33-kDa protein binds to the promoter with the specificity characteristic of DEF-A and stimulates transcription from the ML promoter in transient-expression assays.
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Affiliation(s)
- Humayra Ali
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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4
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Pardo-Mateos A, Young CSH. Adenovirus IVa2 protein plays an important role in transcription from the major late promoter in vivo. Virology 2004; 327:50-9. [PMID: 15327897 DOI: 10.1016/j.virol.2004.06.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Revised: 04/01/2004] [Accepted: 06/01/2004] [Indexed: 10/26/2022]
Abstract
Adenovirus IVa2 protein is essential and multifunctional, with roles in encapsidation and transcriptional activation of the Major Late Promoter (MLP), but the importance of the transcriptional function to viability has not been assessed. To address this question, viral genomes with multiple nonbinding mutations in the MLP downstream elements DE1 and DE2, alone or in combination with nonbinding mutations in the UPE (USF0), were constructed. The results show that DE1/2 and the UPE are functionally redundant, suggesting an important role of IVa2 protein in the activation of the MLP in vivo. Previously, a virus (vIVa2) expressing a 40-kDa IVa2 isoform was created. Neither the DE1/2 mutations nor the USF0 mutations could be recovered in this genetic background. These results suggest that this 40-kDa isoform can play a role in transcription.
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Affiliation(s)
- Almudena Pardo-Mateos
- Department of Microbiology, College of Physicians and Surgeons, Hammer Health Sciences Center, Columbia University, New York, NY 10032, USA
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5
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Abstract
The adenovirus major late promoter (MLP) has played a pre-eminent role in the analysis of transcription initiation in mammalian cells, and is an outstanding example of the ways in which the study of adenovirus has led to fundamental insights into general cellular processes. The aim of this chapter is to give a comprehensive review of the structure and function of this model mammalian promoter. After a brief description of late transcription in the adenovirus replication cycle, the experimental evidence for the current consensus on the genetic structure of the MLP, including a consideration of non-primate adenovirus MLPs, will be reviewed. Next, the functions of the MLP in the viral life cycle will be examined, and some of the problems that remain to be resolved will be addressed. The review ends with some ideas on how the knowledge of the structure and function of the MLP can be used in designing virus vectors for specific experimental purposes.
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Affiliation(s)
- C S H Young
- Columbia University, College of Physicians and Surgeons, Department of Microbiology, 701W 168th Street, New York, NY 10032, USA.
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6
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Okuwaki M, Nagata K. Template activating factor-I remodels the chromatin structure and stimulates transcription from the chromatin template. J Biol Chem 1998; 273:34511-8. [PMID: 9852120 DOI: 10.1074/jbc.273.51.34511] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To study the mechanisms of replication and transcription on chromatin, we have been using the adenovirus DNA complexed with viral basic core proteins, called Ad core. We have identified template activating factor (TAF)-I from uninfected HeLa cells as the factor that stimulates replication and transcription from the Ad core. The nuclease sensitivity assays have revealed that TAF-I remodels the Ad core, thereby making transcription and replication apparatus accessible to the template DNA. To examine whether TAF-I remodels the chromatin consisting of histones, the chromatin structure was reconstituted on the DNA fragment with core histones by the salt dialysis method. The transcription from the reconstituted chromatin was completely repressed, while TAF-I remodeled the chromatin and stimulated the transcription. TAF-I was found to interact with histones. Furthermore, it was shown that TAF-I is capable not only of disrupting the chromatin structure but also of preventing the formation of DNA-histone aggregation and transferring histones to naked DNA. The possible function of TAF-I in conjunction with a histone chaperone activity is discussed.
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Affiliation(s)
- M Okuwaki
- Department of Biomolecular Engineering, Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
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7
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Abstract
Previous work demonstrated that the adenovirus L1 52/55-kDa protein is required for assembly of viral particles, although its exact role in the assembly process is unclear. The 52/55-kDa protein's early expression, however, suggests that it might have other roles at earlier times during infection. To uncover any role the 52/55-kDa protein might have at early times and to better characterize its role in assembly, a mutant adenovirus incapable of expressing the 52/55-kDa protein was constructed (H5pm8001). Analysis of the onset and extent of DNA replication and late protein synthesis revealed that H5pm8001-infected 293 cells entered the late stage of infection at the same time as did adenovirus type 5 (Ad5)-infected cells. Interestingly, H5pm8001-infected cells displayed slightly lower levels of replicated viral DNA and late proteins, suggesting that although not required, the 52/55-kDa protein does augment these activities during infection. Analysis of transcripts produced from the major late and IVa2 promoters indicated a slight reduction in H5pm8001-infected compared to Ad5-infected cells at 18 h postinfection that was not apparent at later times. Analysis of particles formed in H5pm8001 cells revealed that empty capsids could form, suggesting that the 52/55-kDa protein does not function as a scaffolding protein. Subsequent characterization of these particles demonstrated that they lacked any associated viral DNA. These findings indicate that the 52/55 kDa-protein is required to mediate stable association between the viral DNA and empty capsid and suggest that it functions in the DNA encapsidation process.
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Affiliation(s)
- K E Gustin
- Department of Microbiology and Immunology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan 48109-0942, USA
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8
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Lutz P, Rosa-Calatrava M, Kedinger C. The product of the adenovirus intermediate gene IX is a transcriptional activator. J Virol 1997; 71:5102-9. [PMID: 9188576 PMCID: PMC191744 DOI: 10.1128/jvi.71.7.5102-5109.1997] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We have investigated the functional properties of the product of the adenovirus type 5 gene IX. This gene, which is expressed at intermediate times postinfection, encodes a small polypeptide (pIX) of 140 residues that has previously been shown to be incorporated into the viral capsid. Here, we show that pIX, in addition to its structural contribution, exhibits transcriptional properties. In transient transfection experiments, expression of pIX stimulated adenovirus major late promoter activity. The effect was independent of other viral proteins, but the level of promoter activation appeared strongly pIX dose dependent; similar levels of induction were observed with other cellular or viral TATA-containing (but not with TATA-less) promoters. This promoter specificity could be reproduced in a cell-free transcription system by the addition of purified recombinant pIX, further stressing the transcriptional nature of the phenomenon. A preliminary structural analysis of pIX indicated that the integrity of a putative leucine zipper at the carboxy-terminal end of the molecule, as well as elements within the amino-terminal half, was critical for pIX transcriptional activity. The relevance of these findings in adenovirus infection is discussed.
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Affiliation(s)
- P Lutz
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (CNRS/INSERM/ULP), Illkirch, C.U. de Strasbourg, France
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9
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Lutz P, Puvion-Dutilleul F, Lutz Y, Kedinger C. Nucleoplasmic and nucleolar distribution of the adenovirus IVa2 gene product. J Virol 1996; 70:3449-60. [PMID: 8648677 PMCID: PMC190218 DOI: 10.1128/jvi.70.6.3449-3460.1996] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Sequence elements (DE) located downstream of the adenovirus major late promoter start site have previously been shown to be essential for the activation of this promoter after the onset of viral DNA replication. Two proteins (DEF-A and DEF-B) bind to these elements in a late-phase-dependent manner and contribute to this activation. DEF-B corresponds to a dimer of the adenovirus IVa2 gene product (pIVa2, 449 residues), while DEF-A is a heteromeric protein also comprising pIVa2. As revealed by specific immunofluorescence staining of infected cells, pIVa2 is targeted to the nucleus, where it distributes to both nucleoplasmic and nucleolar structures. We have identified the pIVa2 nuclear localization signal (NLS) as a basic peptide element at the C terminus of the protein (residues 432 to 449). An element essential for nucleolar localization (NuLS) has been mapped in the N-terminal part of pIVa2 (between residues 50 and 136). While NuLS activity is dependent upon an intact NLS, we show that both NLS and NuLS functions are independent of specific DNA-binding activity. As visualized by immunoelectron microscopy, pIVa2 is detected in the nucleoplasm at the level of the fibrillogranular network which is active in viral transcription. More surprisingly, pIVa2 accumulates within electron-dense amorphous inclusions found both in the nucleoplasm and in the nucleolus. Altogether, these results suggest that, besides controlling major late promoter transcription, pIVa2 serves additional, as yet unknown functions.
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Affiliation(s)
- P Lutz
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université Louis Pasteur, C.U.de Strasbourg, France
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10
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Lutz P, Kedinger C. Properties of the adenovirus IVa2 gene product, an effector of late-phase-dependent activation of the major late promoter. J Virol 1996; 70:1396-405. [PMID: 8627656 PMCID: PMC189959 DOI: 10.1128/jvi.70.3.1396-1405.1996] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The adenovirus major late promoter is strongly activated after the onset of viral DNA replication. Sequence elements located downstream of the major later promoter start site have previously been shown to be essential for this activation. Two proteins (DEF-A and DEF-B) bind to these elements in a late-phase-dependent manner. DEF-B has been identified as the product of adenovirus intermediate gene IVa2 (pIVa2) (C. Tribouley, P. Lutz, A. Staub, and C. Kedinger, J. Virol. 68:4450-4457, 1994). Here we show that pIVa2, while monomeric in solution, binds to its recognition sequence as a dimer and that two 20-residue amphipathic alpha helices play an essential role in this DNA-binding activity. Attempts to purify DEF-A have failed, but its chromatographic behavior, together with its immunological properties, established that pIVa2 is also a component of this heteromeric protein. In addition, the time course of pIVa2 synthesis during infection correlated with simultaneous detection of the binding of both DEF-A and DEF-B complexes to the downstream elements. Finally, as revealed by immunomicroscopy, pIVa2 is targeted to the nucleus, where it distributes to restricted locations in the nucleoplasm, as well as to the nucleoli. Altogether, these results demonstrate that pIVa2 plays a critical role in the transition from the early to the late phase of the lytic cycle. Furthermore, pIVa2 may serve additional functions yet to be uncovered, as suggested by its presence within the cell nucleolus.
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Affiliation(s)
- P Lutz
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université Louis Pasteur, C.U. de Strasbourg, France
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11
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Massie B, Dionne J, Lamarche N, Fleurent J, Langelier Y. Improved adenovirus vector provides herpes simplex virus ribonucleotide reductase R1 and R2 subunits very efficiently. BIO/TECHNOLOGY (NATURE PUBLISHING COMPANY) 1995; 13:602-8. [PMID: 9634800 DOI: 10.1038/nbt0695-602] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We have constructed a new adenovirus (Ad) expression vector, pAdBM5, that allows for the production of unprecedented levels of recombinant protein in the human 293 cell line using the Ad expression system. The main feature of this vector is a combination of enhancer sequences that increases the activity of the ectopic major late promoter (MLP) in recombinant Ad. In 293 cells infected with helper-free Ad recombinants generated with the pAdBM5 transfer vector, both herpes simplex virus (HSV) ribonucleotide reductase R1 and R2 subunits represent the most abundant polypeptides, accounting for as much as 15-20% of total cellular proteins. Our data suggest that this level of expression is probably very close to the upper limit of the system. Furthermore, when compared to the widely utilized baculovirus (Bac)/Sf9 expression system, the improved Ad vector showed a better performance for the production and purification of active HSV-2 ribonucleotide reductase R1 and R2 subunits. The R2 subunit was about 5-fold more abundant in recombinant Ad-infected 293 cells than in Bac-infected Sf9 cells while the R1 subunit was produced at roughly similar levels with either system. However, the amount of active soluble R1 obtained from recombinant Ad-infected 293 cells was at least 5 times higher because most of the R1 produced in Sf9 cells was insoluble.
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Affiliation(s)
- B Massie
- Institut de Recherches en Biotechnologie, Montréal, Québec, Canada.
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12
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Wagner EK, Guzowski JF, Singh J. Transcription of the herpes simplex virus genome during productive and latent infection. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1995; 51:123-65. [PMID: 7659774 DOI: 10.1016/s0079-6603(08)60878-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- E K Wagner
- Department of Molecular Biology and Biochemistry, University of California, Irvine 92717, USA
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13
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Huang CJ, Wagner EK. The herpes simplex virus type 1 major capsid protein (VP5-UL19) promoter contains two cis-acting elements influencing late expression. J Virol 1994; 68:5738-47. [PMID: 8057455 PMCID: PMC236977 DOI: 10.1128/jvi.68.9.5738-5747.1994] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The herpes simplex virus type 1 (HSV-1) major capsid protein VP5 gene (UL19) is expressed with beta gamma (gamma 1 [leaky late]) kinetics. We have previously described the construction of recombinant HSV-1 in which the VP5 promoter was engineered to control the expression of the bacterial beta-galactosidase gene as a reporter (C.-J. Huang, S. A. Goodart, M. K. Rice, J. F. Guzowski, and E. K. Wagner, J. Virol. 67:5109-5116, 1993). Here we describe further mutational analysis in recombinant viruses. We have precisely defined the boundaries of the VP5 promoter and identified two regions important for both the level and the kinetics of expression. The 5' boundary was located at -48 relative to the initiation site of transcription by analyzing a series of nested deletions in the upstream sequence, and although a number of cis-acting sites influencing transient expression have been identified upstream of this point, these sites have no role in promoter activity during productive infection. Deletion of an Sp1-binding site located between -48 and the TATA box at -30 greatly reduced VP5 promoter activity late but not early after infection. A cis-acting element whose sequence resembles the human immunodeficiency virus type 1 initiator was located between -2 and +10 in the VP5 sequence by characterizing a series of deletions and site-directed block mutations downstream the TATA box. This element defines the 3' limit of the VP5 promoter, and like the upstream element, disruption of this element also inhibited promoter activity late in the productive cycle.
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Affiliation(s)
- C J Huang
- Department of Molecular Biology and Biochemistry, University of California, Irvine 92717
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14
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Tribouley C, Lutz P, Staub A, Kedinger C. The product of the adenovirus intermediate gene IVa2 is a transcriptional activator of the major late promoter. J Virol 1994; 68:4450-7. [PMID: 8207818 PMCID: PMC236370 DOI: 10.1128/jvi.68.7.4450-4457.1994] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
During the course of lytic infection, the adenovirus major late promoter (MLP) is induced to high levels after replication of viral DNA has started. We had previously shown that sequence elements located downstream of the MLP start site were implicated in this late-specific transcriptional activation (DE1, between +85 and +98; DE2, between +100 and +120). Two positive transcription factors involved in this activation have been detected. DEF-A, which specifically binds to DE1 and also to the 3' portion of DE2 (DE2a), and DEF-B, which interacts with the 5' part of DE2 (DE2b). When present together, these two proteins cooperatively assemble onto the DE2 element. We now report the purification of DEF-B and show that it is identical to the product of the adenovirus IVa2 gene product. This conclusion is based on microsequence analysis of DEF-B as well as on the inhibitory effect of antibodies against IVa2 on the DNA-binding activity of DEF-B and also on DE-dependent in vitro transcription. In addition, we show that bacterially synthesized IVa2 protein binds to the DE sequences with the same specificity as DEF-B. Finally, in transfected cells, a recombinant IVa2 protein stimulates MLP activity in a DE-dependent fashion. The physiological implications of these findings are discussed.
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Affiliation(s)
- C Tribouley
- Laboratoire de Génétique Moléculaire des Eucaryotes (CNRS), Unité 184 (INSERM), Institut de Chimie Biologique, Strasbourg, France
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15
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Toth M, Doerfler W, Shenk T. Adenovirus DNA replication facilitates binding of the MLTF/USF transcription factor to the viral major late promoter within infected cells. Nucleic Acids Res 1992; 20:5143-8. [PMID: 1408829 PMCID: PMC334297 DOI: 10.1093/nar/20.19.5143] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The activity of the adenovirus major late promoter is substantially increased as the infection proceeds from the early to late phase. To gain insight into the regulation of this promoter, we analyzed protein-DNA interactions by in vivo DMS and DNasel footprinting during the course of adenovirus infection. Little or no protein interaction at promoter sequences was detected early (5 hr) after infection but strong interactions at the major late transcription factor (MLTF/USF) binding site and at the TATA box were evident late (12 hr) after infection. Comparison of in vivo and in vitro footprints revealed that the in vivo interaction late after infection results from binding of the cellular transcription factor MLTF/USF. Nuclear extracts prepared from uninfected cells as well as cells harvested at 5 and 12 hr after infection contained similar levels of MLTF/USF footprint activity, therefore the lack of a detectable interaction early after infection is not due to reduced levels of the factor early in the viral growth cycle. Viral DNA replication was required for MLTF/USF binding at the major late promoter. These results indicate that DNA replication participates in the regulation of adenovirus late gene expression by facilitating the binding of a transcription factor to the major late promoter.
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Affiliation(s)
- M Toth
- Howard Hughes Medical Institute, Department of Molecular Biology, Princeton University, NJ 08544-1014
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16
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Mondesert G, Tribouley C, Kedinger C. Identification of a novel downstream binding protein implicated in late-phase-specific activation of the adenovirus major late promotor. Nucleic Acids Res 1992; 20:3881-9. [PMID: 1508674 PMCID: PMC334062 DOI: 10.1093/nar/20.15.3881] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The adenovirus major late promotor (MLP) is induced to very high levels after the onset of the viral DNA replication. Previous studies have identified sequence elements located downstream of the MLP startsite (DE1, between +85 and +98; DE2, between +100 and +120) implicated, together with the upstream promoter element, in this late-phase-specific transcriptional activation. One protein (DEF, now renamed DEF-A), induced during the late phase of viral infection, has been identified and shown to bind to the DE1 element (Jansen-Durr et al., 1989, J. Virol. 63, 5124-5132). Here we report about a distinct late-phase-specific protein (DEF-B) and its interactions with DEF-A. DNA-binding studies reveal that DEF-B interacts with the 5' part of DE2 (DE2b), whereas DEF-A, besides its interaction with DE1, also binds to the 3' portion of DE2 (DE2a), but with a lower affinity than for DE1. Furthermore, when added together, DEF-A and DEF-B cooperatively assemble onto the DE2 element as a heteromeric complex which is substantially more stable than the complexes formed by each protein alone. Using an in vivo transcriptional assay of the MLP, we show that DEF-A and DEF-B both have intrinsic transactivating properties.
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Affiliation(s)
- G Mondesert
- Laboratoire de Génétique Moléculaire des Eucaryotes (CNRS), Unité 184 (INSERM), Laboratoire de Chimie Biologique, Faculté de Médecine, Strasbourg, France
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17
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Evidence that USF can interact with only a single general transcription complex at one time. Mol Cell Biol 1992. [PMID: 1549117 DOI: 10.1128/mcb.12.4.1630] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
By in vitro analysis, the major late promoter (MLP) of adenovirus has been shown to be a simple promoter requiring two elements for efficient transcription: a minimal promoter element (MPE), where the general transcription factor-polymerase II complex binds, and a single functional upstream promoter element (UPE) which interacts with USF. Two hundred bases upstream of the MLP cap site and divergently oriented is the IVa2 promoter. This promoter has its own MPE but shares the MLP UPE, suggesting the possibility that these promoters are coordinately regulated. To determine mechanistically how this might function, we replaced the weak IVa2 minimal promoter with a strong MPE (from the viral E1A gene) and observed mutual inhibition of both promoters and unstable transcription factor binding. Only by duplication of the UPE could this inhibition be relieved. When tested independently, both promoters were shown to require the USF site for maximal activity. These results are compatible with a model in which USF can stably interact with only one transcription complex at a time. When two divergently oriented general transcription complexes compete efficiently for binding of USF, transcription is reduced to the same levels as if the USF site were absent.
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18
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Adami G, Babiss LE. Evidence that USF can interact with only a single general transcription complex at one time. Mol Cell Biol 1992; 12:1630-8. [PMID: 1549117 PMCID: PMC369606 DOI: 10.1128/mcb.12.4.1630-1638.1992] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
By in vitro analysis, the major late promoter (MLP) of adenovirus has been shown to be a simple promoter requiring two elements for efficient transcription: a minimal promoter element (MPE), where the general transcription factor-polymerase II complex binds, and a single functional upstream promoter element (UPE) which interacts with USF. Two hundred bases upstream of the MLP cap site and divergently oriented is the IVa2 promoter. This promoter has its own MPE but shares the MLP UPE, suggesting the possibility that these promoters are coordinately regulated. To determine mechanistically how this might function, we replaced the weak IVa2 minimal promoter with a strong MPE (from the viral E1A gene) and observed mutual inhibition of both promoters and unstable transcription factor binding. Only by duplication of the UPE could this inhibition be relieved. When tested independently, both promoters were shown to require the USF site for maximal activity. These results are compatible with a model in which USF can stably interact with only one transcription complex at a time. When two divergently oriented general transcription complexes compete efficiently for binding of USF, transcription is reduced to the same levels as if the USF site were absent.
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Affiliation(s)
- G Adami
- Laboratory of Molecular Cell Biology, Rockefeller University, New York, New York 10021
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