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Charman M, Herrmann C, Weitzman MD. Viral and cellular interactions during adenovirus DNA replication. FEBS Lett 2019; 593:3531-3550. [PMID: 31764999 DOI: 10.1002/1873-3468.13695] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/14/2019] [Accepted: 11/15/2019] [Indexed: 12/30/2022]
Abstract
Adenoviruses represent ubiquitous and clinically significant human pathogens, gene-delivery vectors, and oncolytic agents. The study of adenovirus-infected cells has long been used as an excellent model to investigate fundamental aspects of both DNA virus infection and cellular biology. While many key details supporting a well-established model of adenovirus replication have been elucidated over a period spanning several decades, more recent findings suggest that we have only started to appreciate the complex interplay between viral genome replication and cellular processes. Here, we present a concise overview of adenovirus DNA replication, including the biochemical process of replication, the spatial organization of replication within the host cell nucleus, and insights into the complex plethora of virus-host interactions that influence viral genome replication. Finally, we identify emerging areas of research relating to the replication of adenovirus genomes.
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Affiliation(s)
- Matthew Charman
- Division of Protective Immunity and Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Christin Herrmann
- Division of Protective Immunity and Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Cell and Molecular Biology Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Matthew D Weitzman
- Division of Protective Immunity and Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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2
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Abstract
Adenoviruses have attracted much attention as probes to study biological processes such as DNA replication, transcription, splicing, and cellular transformation. More recently these viruses have been used as gene-transfer vectors and oncolytic agents. On the other hand, adenoviruses are notorious pathogens in people with compromised immune functions. This article will briefly summarize the basic replication strategy of adenoviruses and the key proteins involved and will deal with the new developments since 2006. In addition, we will cover the development of antivirals that interfere with human adenovirus (HAdV) replication and the impact of HAdV on human disease.
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Affiliation(s)
- Rob C Hoeben
- Department of Molecular Cell Biology, Leiden University Medical Centre, 2333 ZC Leiden, The Netherlands.
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3
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Joshi A, Tang J, Kuzma M, Wagner J, Mookerjee B, Filicko J, Carabasi M, Flomenberg N, Flomenberg P. Adenovirus DNA polymerase is recognized by human CD8+ T cells. J Gen Virol 2009; 90:84-94. [PMID: 19088277 DOI: 10.1099/vir.0.002493-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Donor lymphocytes have potential as a treatment for adenovirus (Ad) disease in haematopoietic stem cell transplant (SCT) recipients, but better understanding of Ad-specific T-cell responses is required. Most healthy adults exhibit memory T-cell responses to hexon, a capsid protein synthesized late after infection. However, since the Ad E3-19k downregulates major histocompatibility complex (MHC) class I molecules, cytotoxic T cells (CTLs) targeted to early viral proteins may be more effective in eliminating Ad-infected cells in vivo. Here we show that Ad-specific CTLs recognize the early region 2 proteins DNA polymerase (Pol) and DNA-binding protein (DBP). Firstly, memory Ad-specific CD8(+) T cells were amplified from healthy donors by in vitro stimulation with Ad-infected dendritic cells and found to exhibit MHC-restricted cytotoxicity to targets expressing Pol and DBP. Secondly, gamma interferon responses to HLA A2-binding motif peptides from Pol and DBP were directly detected in peripheral blood mononuclear cells (PBMCs) from a recently infected normal donor. Peptide-specific CTLs generated to Pol and DBP epitopes were confirmed to exhibit HLA A2-restricted killing of targets expressing Pol or DBP. Lastly, Pol-epitope-specific T cells were detected at similar or higher frequencies than hexon and DBP in three of three SCT recipients recovering from invasive Ad disease. Pol epitopes were well conserved among different Ad serotypes. Therefore, Pol is a promising target for immunotherapy of Ad disease.
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Affiliation(s)
- Amita Joshi
- Department of Microbiology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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4
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Abstract
Replication of the adenovirus genome is catalysed by adenovirus DNA polymerase in which the adenovirus preterminal protein acts as a protein primer. DNA polymerase and preterminal protein form a heterodimer which, in the presence of the cellular transcription factors NFI/CTFI and NFIII/Oct-1, binds to the origin of DNA replication. DNA replication is initiated by DNA polymerase mediated transfer of dCMP onto preterminal protein. Further DNA synthesis is catalysed by DNA polymerase in a strand displacement mechanism which also requires adenovirus DNA binding protein. Here, we discuss the role of individual proteins in this process as revealed by biochemical analysis, mutagenesis and molecular modelling.
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Affiliation(s)
- H Liu
- Centre for Biomolecular Science, Biomolecular Science Building, The University of St. Andrews, North Haugh, St. Andrews, KY16 9ST, UK
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5
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de Jong RN, van der Vliet PC, Brenkman AB. Adenovirus DNA replication: protein priming, jumping back and the role of the DNA binding protein DBP. Curr Top Microbiol Immunol 2003; 272:187-211. [PMID: 12747551 DOI: 10.1007/978-3-662-05597-7_7] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The adenovirus (Ad) genome is a linear double-stranded (ds) molecule containing about 36 kilobase pairs. At each end of the genome an approximately 100 base pair (bp) inverted terminal repeat (ITR) is found, the exact length depending on the serotype. To the 5'-end of each ITR, a 55-kDa terminal protein (TP) is covalently coupled. The Ad DNA replication system was one of the first replication systems that could be reconstituted in vitro (Challberg and Kelly 1979). The system requires three virally encoded proteins: precursor TP (pTP), DNA polymerase (Pol) and the DNA binding protein (DBP). In addition, three stimulating human cellular proteins have been identified. These are the transcription factors NFI (Nagata et al. 1982) and Oct-1 (Pruijn et al. 1986) and the type I topoisomerase NFII (Nagata et al. 1983). Ad DNA replication uses a protein primer for replication initiation. The transition from initiation to elongation is marked by a jumping back mechanism (King and van der Vliet 1994), followed by elongation. In order to elongate DBP is required. In this review we discuss the roles of DBP during initiation and elongation and we relate biochemical data on the jumping back mechanism used by Ad Pol to the recently solved crystal structure of a Pol alpha-like replication complex (Franklin et al. 2001). We comment on the conditions and possible functions of jumping back and propose a model to describe the jumping back mechanism.
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Affiliation(s)
- R N de Jong
- University Medical Center, Department of Physiological Chemistry and Center for Biomedical Genetics, Utrecht, The Netherlands.
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6
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de Jong RN, Meijer LAT, van der Vliet PC. DNA binding properties of the adenovirus DNA replication priming protein pTP. Nucleic Acids Res 2003; 31:3274-86. [PMID: 12799455 PMCID: PMC162239 DOI: 10.1093/nar/gkg405] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The precursor terminal protein pTP is the primer for the initiation of adenovirus (Ad) DNA replication and forms a heterodimer with Ad DNA polymerase (pol). Pol can couple dCTP to pTP directed by the fourth nucleotide of the viral genome template strand in the absence of other replication proteins, which suggests that pTP/pol binding destabilizes the origin or stabilizes an unwound state. We analyzed the contribution of pTP to pTP/pol origin binding using various DNA oligonucleotides. We show that two pTP molecules bind cooperatively to short DNA duplexes, while longer DNA fragments are bound by single pTP molecules as well. Cooperative binding to short duplexes is DNA sequence independent and most likely mediated by protein/protein contacts. Furthermore, we observed that pTP binds single-stranded (ss)DNA with a minimal length of approximately 35 nt and that random ssDNA competed 25-fold more efficiently than random duplex DNA for origin binding by pTP. Remarkably, short DNA fragments with two opposing single strands supported monomeric pTP binding. pTP did not stimulate, but inhibited strand displacement by the Ad DNA binding and unwinding protein DBP. These observations suggest a mechanism in which the ssDNA affinity of pTP stabilizes Ad pol on partially unwound origin DNA.
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Affiliation(s)
- R N de Jong
- Department of Physiological Chemistry, University Medical Center Utrecht and Center for Biomedical Genetics, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands
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7
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Brenkman AB, Breure EC, van der Vliet PC. Molecular architecture of adenovirus DNA polymerase and location of the protein primer. J Virol 2002; 76:8200-7. [PMID: 12134025 PMCID: PMC155156 DOI: 10.1128/jvi.76.16.8200-8207.2002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2002] [Accepted: 05/13/2002] [Indexed: 11/20/2022] Open
Abstract
Adenovirus (Ad) DNA polymerase (pol) belongs to the distinct subclass of the polalpha family of DNA pols that employs the precursor terminal protein (pTP) as primer. Ad pol forms a stable heterodimer with this primer, and together, they bind specifically to the core origin in order to start replication. After initiation of Ad replication, the resulting pTP-trinucleotide intermediate jumps back and pTP starts to dissociate. Compared to free Ad pol, the pTP-pol complex shows reduced polymerase and exonuclease activities, but the reason for this is not understood. Furthermore, the interaction domains between these proteins have not been defined and the contribution of each protein to origin binding is unclear. To address these questions, we used oligonucleotides with a translocation block and show here that pTP binds at the entrance of the primer binding groove of Ad pol, thereby explaining the decreased synthetic activities of the pTP-pol complex and providing insight into how pTP primes Ad replication. Employing an exonuclease-deficient mutant polymerase, we further show that the polymerase and exonuclease active sites of Ad pol are spatially distinct and that the exonuclease activity of Ad pol is located at the N-terminal part of the protein. In addition, by probing the distances between both active sites and the surface of Ad pol, we show that Ad pol binds a DNA region of 14 to 15 nucleotides. Based on these results, a model for binding of the pTP-pol complex at the origin of replication is proposed.
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Affiliation(s)
- Arjan B Brenkman
- University Medical Centre, Department of Physiological Chemistry and Centre for Biomedical Genetics, Utrecht, The Netherlands
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8
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Brenkman AB, Heideman MR, Truniger V, Salas M, van der Vliet PC. The (I/Y)XGG motif of adenovirus DNA polymerase affects template DNA binding and the transition from initiation to elongation. J Biol Chem 2001; 276:29846-53. [PMID: 11390396 DOI: 10.1074/jbc.m103159200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Adenovirus DNA polymerase (Ad pol) is a eukaryotic-type DNA polymerase involved in the catalysis of protein-primed initiation as well as DNA polymerization. The functional significance of the (I/Y)XGG motif, highly conserved among eukaryotic-type DNA polymerases, was analyzed in Ad pol by site-directed mutagenesis of four conserved amino acids. All mutant polymerases could bind primer-template DNA efficiently but were impaired in binding duplex DNA. Three mutant polymerases required higher nucleotide concentrations for effective polymerization and showed higher exonuclease activity on double-stranded DNA. These observations suggest a local destabilization of DNA substrate at the polymerase active site. In agreement with this, the mutant polymerases showed reduced initiation activity and increased K(m)(app) for the initiating nucleotide, dCMP. Interestingly, one mutant polymerase, while capable of elongating on the primer-template DNA, failed to elongate after protein priming. Further investigation of this mutant polymerase showed that polymerization activity decreased after each polymerization step and ceased completely after formation of the precursor terminal protein-trinucleotide (pTP-CAT) initiation intermediate. Our results suggest that residues in the conserved motif (I/Y)XGG in Ad pol are involved in binding the template strand in the polymerase active site and play an important role in the transition from initiation to elongation.
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Affiliation(s)
- A B Brenkman
- University Medical Center, Department of Physiological Chemistry and Center for Biomedical Genetics, Utrecht, The Netherlands
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9
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Liu H, Naismith JH, Hay RT. Identification of conserved residues contributing to the activities of adenovirus DNA polymerase. J Virol 2000; 74:11681-9. [PMID: 11090167 PMCID: PMC112450 DOI: 10.1128/jvi.74.24.11681-11689.2000] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Adenovirus codes for a DNA polymerase that is a member of the DNA polymerase alpha family and uses a protein primer for initiation of DNA synthesis. It contains motifs characteristic of a proofreading 3'-5'-exonuclease domain located in the N-terminal region and several polymerase motifs located in the C-terminal region. To determine the role of adenovirus DNA polymerase in DNA replication, 22 site-directed mutations were introduced into the conserved DNA polymerase motifs in the C-terminal region of adenovirus DNA polymerase and the mutant forms were expressed in insect cells using a baculovirus expression system. Each mutant enzyme was tested for DNA binding activity, the ability to interact with pTP, DNA polymerase catalytic activity, and the ability to participate in the initiation of adenovirus DNA replication. The mutant phenotypes identify functional domains within the adenovirus DNA polymerase and allow discrimination between the roles of conserved residues in the various activities carried out by the protein. Using the functional data in this study and the previously published structure of the bacteriophage RB69 DNA polymerase (J. Wang et al., Cell 89:1087-1099, 1997), it is possible to envisage how the conserved domains in the adenovirus DNA polymerase function.
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Affiliation(s)
- H Liu
- Centre for Biomolecular Science, The University of St. Andrews, North Haugh, St. Andrews KY16 9ST, United Kingdom
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10
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de Jong RN, van der Vliet PC. Mechanism of DNA replication in eukaryotic cells: cellular host factors stimulating adenovirus DNA replication. Gene 1999; 236:1-12. [PMID: 10433960 DOI: 10.1016/s0378-1119(99)00249-8] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Replication of adenovirus (Ad) DNA depends on interactions between three viral and three cellular proteins. Human transcription factors NFI and Oct-1 recruit the Ad DNA polymerase to the origin of DNA replication as a complex with the Ad protein primer pTP. High affinity and specificity DNA binding to recognition sites in this origin by the transcription factors stimulate and stabilize pre-initiation complex formation to compensate for the low binding specificity of the pTP/pol complex. In this review, we discuss the properties of NFI and Oct-1 and the mechanism by which they enhance initiation of DNA replication. We propose a model that describes the dynamics of initiation and elongation as well as the assembly and disassembly of the pre-initiation complex.
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Affiliation(s)
- R N de Jong
- Laboratory for Physiological Chemistry and Centre for Biomedical Genetics, Utrecht University, Utrecht, The Netherlands
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11
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Reddy PS, Idamakanti N, Song JY, Lee JB, Hyun BH, Park JH, Cha SH, Bae YT, Tikoo SK, Babiuk LA. Nucleotide sequence and transcription map of porcine adenovirus type 3. Virology 1998; 251:414-26. [PMID: 9837805 DOI: 10.1006/viro.1998.9418] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The complete nucleotide sequence of porcine adenovirus type 3 was determined and a transcriptional map for the genome was constructed. The size of the genome is 34094 bp in length with an unusually high G + C content (63.7%), the highest thus far reported for any adenovirus. Overall organization of the genome is similar to that for previously sequenced adenoviral DNAs, but there also were distinct differences. The late regions genes are organized into six families, instead of five as they are in human adenovirus type 2. In contrast to bovine adenovirus type 3 and ovine adenovirus, which lack virion-associated RNA genes, the nucleotide sequence analysis of the viral genome indicates that it encodes one short VA RNA species. With the exception of the fiber and a 33-kDa nonstructural protein, the predicted amino acid sequences of the open reading frames in the late regions and the E2 region and IVa2 exhibited a high level of homology, whereas the deduced amino acid sequences of ORFs in E1, E3, and E4 regions, and the pIX showed a lesser homology with the corresponding proteins of other adenoviruses. The proteins V, VII, and IX are unusually long, and the protein VII lacks the consensus protease cleavage site. Genomic and cDNA sequence analysis has identified promoters, cap sites, intron-exon boundaries, polyadenylation signals, and polyadenylation sites in the viral genome.
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Affiliation(s)
- P S Reddy
- Veterinary Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E3, Canada.
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12
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Barnes MH, Leo CJ, Brown NC. DNA polymerase III of Gram-positive eubacteria is a zinc metalloprotein conserving an essential finger-like domain. Biochemistry 1998; 37:15254-60. [PMID: 9799485 DOI: 10.1021/bi981113m] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
DNA polymerase III (pol III) of Gram-positive eubacteria is a catalytically bifunctional DNA polymerase:3'-5' exonuclease [Low, R. L., Rashbaum, S. A., and Cozzarelli, N. R. (1976) J. Biol.Chem. 251, 1311-1325]. The pol III protein conserves, between its exonuclease and dNTP binding sites, a 35-residue segment of primary structure with the potential to form a zinc finger-like structure [Berg, J. M. (1990) Ann. Rev. Biochem. 19, 405-421]. This paper describes results of experiments which probe the capacity of this segment to bind zinc and the role of this segment in enzyme function. The results of metal and mutational analysis of a model pol III derived from Bacillus subtilis indicate that (i) the Gram-positive pol III is a metalloprotein containing tightly bound zinc in a stoichiometry of 1, (ii) the zinc atom is bound within the 35-residue segment, likely in one of two probable finger-like structures, and (iii) the integrity of the zinc-bound structure is specifically critical to the formation and/or function of the enzyme's polymerase site.
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Affiliation(s)
- M H Barnes
- Department of Pharmacology and Molecular Toxicology, University of Massachusetts Medical School, Worcester 01655-0126, USA
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13
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Baxi MK, Reddy PS, Zakhartchouk AN, Idamakanti N, Pyne C, Babiuk LA, Tikoo SK. Characterization of bovine adenovirus type 3 early region 2B. Virus Genes 1998; 16:313-6. [PMID: 9654686 DOI: 10.1023/a:1008047225872] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We have determined the nucleotide sequence of a 6999 base pair region of bovine adenovirus-3 covering map units 9.0 to 29.17, which contained the adenovirus homologs of IVa2 protein and the DNA replication proteins, precursor of terminal protein and DNA polymerase proteins. Analysis of the sequence for cis-acting elements suggests that transcripts of DNA polymerase and precursor of terminal protein are 3' co-terminal. In addition, this region also contains major late promoter sequence. The sequence to the left of IVa2 contains the ORF of pIX with a potential TATA box immediately upstream and two polyadenylation consensus signals immediately downstream of the ORF.
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Affiliation(s)
- M K Baxi
- Veterinary Infectious Disease Organization, University of Saskatchewan, Saskatoon, Canada
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14
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Parker EJ, Botting CH, Webster A, Hay RT. Adenovirus DNA polymerase: domain organisation and interaction with preterminal protein. Nucleic Acids Res 1998; 26:1240-7. [PMID: 9469832 PMCID: PMC147410 DOI: 10.1093/nar/26.5.1240] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Adenovirus DNA polymerase is one of three viral proteins and two cellular proteins required for replication of the adenovirus genome. During initiation of viral DNA synthesis the viral DNA polymerase transfers dCMP onto the adenovirus preterminal protein, to which it is tightly bound. The domain structure of the 140 kDa DNA polymerase has been probed by partial proteolysis and the sites of proteolytic cleavage determined by N-terminal sequencing. At least four domains can be recognised within the DNA polymerase. Adenovirus preterminal protein interacts with three of the four proteolytically derived domains. This was confirmed by cloning and expression of each of the individual domains. These data indicate that, like other members of the pol alpha family of DNA polymerases, the adenovirus DNA polymerase has a multidomain structure and that interaction with preterminal protein takes place with non-contiguous regions of the polypeptide chain over a large surface area of the viral DNA polymerase.
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Affiliation(s)
- E J Parker
- School of Biomedical Science, Irvine Building, University of St Andrews, North Street, St Andrews, Fife KY16 9AL, UK
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15
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Vrati S, Brookes DE, Boyle DB, Both GW. Nucleotide sequence of ovine adenovirus tripartite leader sequence and homologues of the IVa2, DNA polymerase and terminal proteins. Gene 1996; 177:35-41. [PMID: 8921842 DOI: 10.1016/0378-1119(96)00266-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Ovine adenovirus OAV287 was previously isolated from sheep in Western Australia. Here we describe a portion of its genome between map units 10.3 and 31.7 which includes major ORFs for homologues of the IVa2 polypeptide and the DNA replication proteins, Terminal protein and DNA polymerase, as well as the N-terminal portion of the 52/55-kDa polypeptide. In addition, as a prelude to possible adaptation of this virus as a vector we have mapped the elements which make up the tripartite leader sequence of late mRNAs, thereby defining the probable location of the OAV major late promoter. In other human and animal adenovirus genomes, one or two VA RNA genes are encoded between the ORFs for Terminal protein and 52/55-kDa polypeptides. In OAV, these ORFs overlap, suggesting that if VA RNA genes are present, they may lie elsewhere in the OAV genome.
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Affiliation(s)
- S Vrati
- CSIRO Division of Biomolecular Engineering, North Ryde, N.S.W., Australia
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16
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Abstract
Pyridoxal phosphate modification of adenovirus DNA polymerase results in loss of DNA polymerase activity, whereas the 3' --> 5' exonuclease activity is unaffected. Inhibition by pyridoxal phosphate is time-dependent, displays saturation kinetics, and is reversible in the presence of excess primary amine unless the pyridoxal phosphate-enzyme adduct is first reduced with NaBH4. Thus, inhibition is the consequence of Schiff base formation between the aldehyde moiety of pyridoxal phosphate and primary amino groups on the enzyme. In addition to inhibiting DNA polymerase activity, pyridoxal phosphate also inhibited the ability of the enzyme to initiate viral DNA replication, by transfer of dCMP onto the preterminal protein. Neither template-primer nor dNTP protect against pyridoxal phosphate inhibition, but the combination of template-primer and complementary substrate dNTP protected both initiation and DNA polymerase activities. Thus, it is likely that both the dCMP transfer activity required for initiation and DNA polymerase activity are carried out at the same site of the enzyme.
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Affiliation(s)
- A Monaghan
- School of Biological and Medical Sciences, Irvine Building, University of St. Andrews, Fife KY16 9AL, Scotland, United Kingdom
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17
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Angeletti PC, Engler JA. Tyrosine kinase-dependent release of an adenovirus preterminal protein complex from the nuclear matrix. J Virol 1996; 70:3060-7. [PMID: 8627784 PMCID: PMC190167 DOI: 10.1128/jvi.70.5.3060-3067.1996] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Adenovirus (Ad) replicative complexes form at discrete sites on the nuclear matrix (NM) through the interaction of Ad preterminal protein (pTP). The NM is a highly salt-resistant fibrillar network which is known to anchor transcription, mRNA splicing, and DNA replication complexes. Incubation of rATP with NM to which pTP was bound caused the release of pTP as a pTP-NM complex with a size of 220 to 230 kDa; incubation with 5' adenylylimidodiphosphate (rAMP-PNP) showed no significant release, indicating that rATP hydrolysis was required. With NM extracts, it was shown that a pTP-NM complex which was capable of binding Ad origin DNA could be reconstituted in vitro. A number of high-molecular-weight NM proteins ranging in size from 120 to 200 kDa were identified on Far Western blots for their ability to bind pTP. rATP-dependent release of pTP from the NM was inhibited in a dose-dependent fashion by the addition of tyrosine kinase inhibitors, such as quercetin, methyl-2,5-dihydroxycinnamate, or genistein. NM-mediated phosphorylation of a poly(Glu, Tyr) substrate was also significantly abrogated by the addition of these compounds. rATP-dependent release of Ad DNA termini bound to the NM via pTP was also blocked by the addition of these inhibitors. These results indicate that a tyrosine kinase mechanism controls the release of pTP from its binding sites on the NM. These data support the concept that phosphorylation may play a key role in the modulation of pTP binding sites on the NM.
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Affiliation(s)
- P C Angeletti
- Department of Biochemistry and Molecular Genetics, Schools of Medicine and Dentistry, University of Alabama at Birmingham, 35294-0005, USA
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18
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Stanglmaier M, Winnacker EL. Cloning, sequence determination and functional expression of the genes encoding adenovirus type-4 polymerase and the terminal protein precursor. Gene 1996; 168:177-82. [PMID: 8654940 DOI: 10.1016/0378-1119(95)00801-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Sequences of the open reading frames encoding adenovirus type 4 (Ad4) DNA polymerase and the terminal protein precursor were determined. Sequence comparisons with the corresponding genes and proteins from Ad2 and Ad5 show high overall identity, but significant differences in those portions of the two proteins thought to be essential for their biological activities. Both Ad4 proteins were functionally expressed in insect cells from the corresponding cDNAs.
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Affiliation(s)
- M Stanglmaier
- Institut für Biochemie der Universität München, Germany
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19
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Harrington L, Hull C, Crittenden J, Greider C. Gel shift and UV cross-linking analysis of Tetrahymena telomerase. J Biol Chem 1995; 270:8893-901. [PMID: 7721797 DOI: 10.1074/jbc.270.15.8893] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Telomerase is an unusual ribonucleoprotein that synthesizes new telomeres onto chromosome ends. The enzyme has been most extensively characterized in ciliates, where the RNA component has been cloned from several species, and its elongation properties have been characterized in detail. To understand the substrate specificity and protein composition of telomerase, we have used gel shift and UV cross-linking to characterize the enzyme from the ciliate Tetrahymena thermophila. In a mobility shift assay, a complex was identified that contained telomerase RNA, co-purified with telomerase activity, and was sensitive to nuclease treatment. The mobility shift complexes specifically formed using several different single-stranded, telomeric sequences but not non-telomeric primers. These results suggest that the specificity of telomerase for G-rich primer sequences occurs at least in part at the level of primer binding. UV cross-linking analysis identified a 100-kDa cross-linked protein that may be a telomerase component.
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Affiliation(s)
- L Harrington
- Cold Spring Harbor Laboratory, New York 11724, USA
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20
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Affiliation(s)
- P C Van der Vliet
- Laboratory for Physiological Chemistry, University of Utrecht, The Netherlands
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Ramachandra M, Padmanabhan R. Expression, Nuclear Transport, and Phosphorylation of Adenovirus DNA Replication Proteins. Curr Top Microbiol Immunol 1995. [DOI: 10.1007/978-3-642-79499-5_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Hay RT, Freeman A, Leith I, Monaghan A, Webster A. Molecular interactions during adenovirus DNA replication. Curr Top Microbiol Immunol 1995; 199 ( Pt 2):31-48. [PMID: 7555069 DOI: 10.1007/978-3-642-79499-5_2] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- R T Hay
- School of Biological and Medical Sciences, University of St. Andrews, Scotland, UK
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Kusukawa J, Ramachandra M, Nakano R, Padmanabhan R. Phosphorylation-dependent interaction of adenovirus preterminal protein with the viral origin of DNA replication. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)42153-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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