1
|
Pilotto S, Sýkora M, Cackett G, Dulson C, Werner F. Structure of the recombinant RNA polymerase from African Swine Fever Virus. Nat Commun 2024; 15:1606. [PMID: 38383525 PMCID: PMC10881513 DOI: 10.1038/s41467-024-45842-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 02/06/2024] [Indexed: 02/23/2024] Open
Abstract
African Swine Fever Virus is a Nucleo-Cytoplasmic Large DNA Virus that causes an incurable haemorrhagic fever in pigs with a high impact on global food security. ASFV replicates in the cytoplasm of the infected cell and encodes its own transcription machinery that is independent of cellular factors, however, not much is known about how this system works at a molecular level. Here, we present methods to produce recombinant ASFV RNA polymerase, functional assays to screen for inhibitors, and high-resolution cryo-electron microscopy structures of the ASFV RNAP in different conformational states. The ASFV RNAP bears a striking resemblance to RNAPII with bona fide homologues of nine of its twelve subunits. Key differences include the fusion of the ASFV assembly platform subunits RPB3 and RPB11, and an unusual C-terminal domain of the stalk subunit vRPB7 that is related to the eukaryotic mRNA cap 2´-O-methyltransferase 1. Despite the high degree of structural conservation with cellular RNA polymerases, the ASFV RNAP is resistant to the inhibitors rifampicin and alpha-amanitin. The cryo-EM structures and fully recombinant RNAP system together provide an important tool for the design, development, and screening of antiviral drugs in a low biosafety containment environment.
Collapse
Affiliation(s)
- Simona Pilotto
- Institute for Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Michal Sýkora
- Institute for Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Gwenny Cackett
- Institute for Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Christopher Dulson
- Institute for Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Finn Werner
- Institute for Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
| |
Collapse
|
2
|
Mirzakhanyan Y, Gershon P. The Vaccinia virion: Filling the gap between atomic and ultrastructure. PLoS Pathog 2019; 15:e1007508. [PMID: 30615658 PMCID: PMC6336343 DOI: 10.1371/journal.ppat.1007508] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 01/17/2019] [Accepted: 12/06/2018] [Indexed: 01/19/2023] Open
Abstract
We have investigated the molecular-level structure of the Vaccinia virion in situ by protein-protein chemical crosslinking, identifying 4609 unique-mass crosslink ions at an effective FDR of 0.33%, covering 2534 unique pairs of crosslinked protein positions, 625 of which were inter-protein. The data were statistically non-random and rational in the context of known structures, and showed biological rationality. Crosslink density strongly tracked the individual proteolytic maturation products of p4a and p4b, the two major virion structural proteins, and supported the prediction of transmembrane domains within membrane proteins. A clear sub-network of four virion structural proteins provided structural insights into the virion core wall, and proteins VP8 and A12 formed a strongly-detected crosslinked pair with an apparent structural role. A strongly-detected sub-network of membrane proteins A17, H3, A27 and A26 represented an apparent interface of the early-forming virion envelope with structures added later during virion morphogenesis. Protein H3 seemed to be the central hub not only for this sub-network but also for an 'attachment protein' sub-network comprising membrane proteins H3, ATI, CAHH(D8), A26, A27 and G9. Crosslinking data lent support to a number of known interactions and interactions within known complexes. Evidence is provided for the membrane targeting of genome telomeres. In covering several orders of magnitude in protein abundance, this study may have come close to the bottom of the protein-protein crosslinkome of an intact organism, namely a complex animal virus.
Collapse
Affiliation(s)
- Yeva Mirzakhanyan
- Department of Molecular Biology & Biochemistry, UC-Irvine, Irvine, California, United States of America
| | - Paul Gershon
- Department of Molecular Biology & Biochemistry, UC-Irvine, Irvine, California, United States of America
| |
Collapse
|
3
|
Identification of Vaccinia Virus Replisome and Transcriptome Proteins by Isolation of Proteins on Nascent DNA Coupled with Mass Spectrometry. J Virol 2017; 91:JVI.01015-17. [PMID: 28747503 DOI: 10.1128/jvi.01015-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 07/19/2017] [Indexed: 12/22/2022] Open
Abstract
Poxviruses replicate within the cytoplasm and encode proteins for DNA and mRNA synthesis. To investigate poxvirus replication and transcription from a new perspective, we incorporated 5-ethynyl-2'-deoxyuridine (EdU) into nascent DNA in cells infected with vaccinia virus (VACV). The EdU-labeled DNA was conjugated to fluor- or biotin-azide and visualized by confocal, superresolution, and transmission electron microscopy. Nuclear labeling decreased dramatically after infection, accompanied by intense labeling of cytoplasmic foci. The nascent DNA colocalized with the VACV single-stranded DNA binding protein I3 in multiple puncta throughout the interior of factories, which were surrounded by endoplasmic reticulum. Complexes containing EdU-biotin-labeled DNA cross-linked to proteins were captured on streptavidin beads. After elution and proteolysis, the peptides were analyzed by mass spectrometry to identify proteins associated with nascent DNA. The known viral replication proteins, a telomere binding protein, and a protein kinase were associated with nascent DNA, as were the DNA-dependent RNA polymerase and intermediate- and late-stage transcription initiation and elongation factors, plus the capping and methylating enzymes. These results suggested that the replicating pool of DNA is transcribed and that few if any additional viral proteins directly engaged in replication and transcription remain to be discovered. Among the host proteins identified by mass spectrometry, topoisomerases IIα and IIβ and PCNA were noteworthy. The association of the topoisomerases with nascent DNA was dependent on expression of the viral DNA ligase, in accord with previous proteomic studies. Further investigations are needed to determine possible roles for PCNA and other host proteins detected.IMPORTANCE Poxviruses, unlike many well-characterized animal DNA viruses, replicate entirely within the cytoplasm of animal cells, raising questions regarding the relative roles of viral and host proteins. We adapted newly developed procedures for click chemistry and iPOND (Isolation of proteins on nascent DNA) to investigate vaccinia virus (VACV), the prototype poxvirus. Nuclear DNA synthesis ceased almost immediately following VACV infection, followed swiftly by the synthesis of viral DNA within discrete cytoplasmic foci. All viral proteins known from genetic and proteomic studies to be required for poxvirus DNA replication were identified in the complexes containing nascent DNA. The additional detection of the viral DNA-dependent RNA polymerase and intermediate and late transcription factors provided evidence for a temporal coupling of replication and transcription. Further studies are needed to assess the potential roles of host proteins, including topoisomerases IIα and IIβ and PCNA, which were found associated with nascent DNA.
Collapse
|
4
|
Multisubunit DNA-Dependent RNA Polymerases from Vaccinia Virus and Other Nucleocytoplasmic Large-DNA Viruses: Impressions from the Age of Structure. Microbiol Mol Biol Rev 2017; 81:81/3/e00010-17. [PMID: 28701329 DOI: 10.1128/mmbr.00010-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The past 17 years have been marked by a revolution in our understanding of cellular multisubunit DNA-dependent RNA polymerases (MSDDRPs) at the structural level. A parallel development over the past 15 years has been the emerging story of the giant viruses, which encode MSDDRPs. Here we link the two in an attempt to understand the specialization of multisubunit RNA polymerases in the domain of life encompassing the large nucleocytoplasmic DNA viruses (NCLDV), a superclade that includes the giant viruses and the biochemically well-characterized poxvirus vaccinia virus. The first half of this review surveys the recently determined structural biology of cellular RNA polymerases for a microbiology readership. The second half discusses a reannotation of MSDDRP subunits from NCLDV families and the apparent specialization of these enzymes by virus family and by subunit with regard to subunit or domain loss, subunit dissociability, endogenous control of polymerase arrest, and the elimination/customization of regulatory interactions that would confer higher-order cellular control. Some themes are apparent in linking subunit function to structure in the viral world: as with cellular RNA polymerases I and III and unlike cellular RNA polymerase II, the viral enzymes seem to opt for speed and processivity and seem to have eliminated domains associated with higher-order regulation. The adoption/loss of viral RNA polymerase proofreading functions may have played a part in matching intrinsic mutability to genome size.
Collapse
|
5
|
Abstract
This Reflections article describes my early work on viral enzymes and the discovery of mRNA capping, how my training in medicine and biochemistry merged as I evolved into a virologist, the development of viruses as vaccine vectors, and how scientific and technological developments during the 1970s and beyond set the stage for the interrogation of nearly every step in the reproductive cycle of vaccinia virus (VACV), a large DNA virus with about 200 genes. The reader may view this article as a work in progress, because I remain actively engaged in research at the National Institutes of Health (NIH) notwithstanding 50 memorable years there.
Collapse
Affiliation(s)
- Bernard Moss
- From the Laboratory of Viral Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892
| |
Collapse
|
6
|
Oliveira GP, Andrade ACDSP, Rodrigues RAL, Arantes TS, Boratto PVM, Silva LKDS, Dornas FP, Trindade GDS, Drumond BP, La Scola B, Kroon EG, Abrahão JS. Promoter Motifs in NCLDVs: An Evolutionary Perspective. Viruses 2017; 9:v9010016. [PMID: 28117683 PMCID: PMC5294985 DOI: 10.3390/v9010016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/30/2016] [Accepted: 01/05/2017] [Indexed: 01/18/2023] Open
Abstract
For many years, gene expression in the three cellular domains has been studied in an attempt to discover sequences associated with the regulation of the transcription process. Some specific transcriptional features were described in viruses, although few studies have been devoted to understanding the evolutionary aspects related to the spread of promoter motifs through related viral families. The discovery of giant viruses and the proposition of the new viral order Megavirales that comprise a monophyletic group, named nucleo-cytoplasmic large DNA viruses (NCLDV), raised new questions in the field. Some putative promoter sequences have already been described for some NCLDV members, bringing new insights into the evolutionary history of these complex microorganisms. In this review, we summarize the main aspects of the transcription regulation process in the three domains of life, followed by a systematic description of what is currently known about promoter regions in several NCLDVs. We also discuss how the analysis of the promoter sequences could bring new ideas about the giant viruses’ evolution. Finally, considering a possible common ancestor for the NCLDV group, we discussed possible promoters’ evolutionary scenarios and propose the term “MEGA-box” to designate an ancestor promoter motif (‘TATATAAAATTGA’) that could be evolved gradually by nucleotides’ gain and loss and point mutations.
Collapse
Affiliation(s)
- Graziele Pereira Oliveira
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil.
| | - Ana Cláudia Dos Santos Pereira Andrade
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil.
| | - Rodrigo Araújo Lima Rodrigues
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil.
| | - Thalita Souza Arantes
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil.
| | - Paulo Victor Miranda Boratto
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil.
| | - Ludmila Karen Dos Santos Silva
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil.
| | - Fábio Pio Dornas
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil.
| | - Giliane de Souza Trindade
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil.
| | - Betânia Paiva Drumond
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil.
| | - Bernard La Scola
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes (URMITE) UM63 CNRS 7278 IRD 198 INSERM U1095, Aix-Marseille Université., 27 Boulevard Jean Moulin, Faculté de Médecine, 13385 Marseille Cedex 05, France.
| | - Erna Geessien Kroon
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil.
| | - Jônatas Santos Abrahão
- Laboratório de Vírus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Minas Gerais, Brazil.
| |
Collapse
|
7
|
Priet S, Lartigue A, Debart F, Claverie JM, Abergel C. mRNA maturation in giant viruses: variation on a theme. Nucleic Acids Res 2015; 43:3776-88. [PMID: 25779049 PMCID: PMC4402537 DOI: 10.1093/nar/gkv224] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 03/03/2015] [Accepted: 03/04/2015] [Indexed: 12/02/2022] Open
Abstract
Giant viruses from the Mimiviridae family replicate entirely in their host cytoplasm where their genes are transcribed by a viral transcription apparatus. mRNA polyadenylation uniquely occurs at hairpin-forming palindromic sequences terminating viral transcripts. Here we show that a conserved gene cluster both encode the enzyme responsible for the hairpin cleavage and the viral polyA polymerases (vPAP). Unexpectedly, the vPAPs are homodimeric and uniquely self-processive. The vPAP backbone structures exhibit a symmetrical architecture with two subdomains sharing a nucleotidyltransferase topology, suggesting that vPAPs originate from an ancestral duplication. A Poxvirus processivity factor homologue encoded by Megavirus chilensis displays a conserved 5'-GpppA 2'O methyltransferase activity but is also able to internally methylate the mRNAs' polyA tails. These findings elucidate how the arm wrestling between hosts and their viruses to access the translation machinery is taking place in Mimiviridae.
Collapse
Affiliation(s)
- Stéphane Priet
- Architecture et Fonction des Macromolécules Biologiques, CNRS UMR 7257, Aix-Marseille Université, 163 Avenue de Luminy, Case 932, 13288 Marseille cedex 9, France
| | - Audrey Lartigue
- Structural and Genomic Information Laboratory, UMR 7256 (IMM FR 3479) CNRS Aix-Marseille Université, 163 Avenue de Luminy, Case 934, 13288 Marseille cedex 9, France
| | - Françoise Debart
- IBMM, UMR 5247, CNRS-UM1-UM2, Université Montpellier 2, Place Eugène Bataillon, 34095 Montpellier, France
| | - Jean-Michel Claverie
- Structural and Genomic Information Laboratory, UMR 7256 (IMM FR 3479) CNRS Aix-Marseille Université, 163 Avenue de Luminy, Case 934, 13288 Marseille cedex 9, France APHM, FR-13385 Marseille, France
| | - Chantal Abergel
- Structural and Genomic Information Laboratory, UMR 7256 (IMM FR 3479) CNRS Aix-Marseille Université, 163 Avenue de Luminy, Case 934, 13288 Marseille cedex 9, France
| |
Collapse
|
8
|
|
9
|
Genome-wide analysis of the 5' and 3' ends of vaccinia virus early mRNAs delineates regulatory sequences of annotated and anomalous transcripts. J Virol 2011; 85:5897-909. [PMID: 21490097 DOI: 10.1128/jvi.00428-11] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Poxviruses are large DNA viruses that encode a multisubunit RNA polymerase, stage-specific transcription factors, and enzymes that cap and polyadenylate mRNAs within the cytoplasm of infected animal cells. Genome-wide microarray and RNA-seq technologies have been used to profile the transcriptome of vaccinia virus (VACV), the prototype member of the family. Here, we adapted tag-based methods in conjunction with SOLiD and Illumina deep sequencing platforms to determine the precise 5' and 3' ends of VACV early mRNAs and map the putative transcription start sites (TSSs) and polyadenylation sites (PASs). Individual and clustered TSSs were found preceding 104 annotated open reading frames (ORFs), excluding pseudogenes. In the majority of cases, a 15-nucleotide consensus core motif was present upstream of the ORF. This motif, however, was also present at numerous other locations, indicating that it was insufficient for transcription initiation. Further analysis revealed a 10-nucleotide AT-rich spacer following functional core motifs that may facilitate DNA unwinding. Additional putative TSSs occurred in anomalous locations that may expand the functional repertoire of the VACV genome. However, many of the anomalous TSSs lacked an upstream core motif, raising the possibility that they arose by a processing mechanism as has been proposed for eukaryotic systems. Discrete and clustered PASs occurred about 40 nucleotides after an UUUUUNU termination signal. However, a large number of PASs were not preceded by this motif, suggesting alternative polyadenylation mechanisms. Pyrimidine-rich coding strand sequences were found immediately upstream of both types of PASs, signifying an additional feature of VACV 3'-end formation and polyadenylation.
Collapse
|
10
|
Transcriptional and structural analyses of Amsacta moorei entomopoxvirus protein kinase gene (AMV197, pk). ANN MICROBIOL 2010. [DOI: 10.1007/s13213-010-0082-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
|
11
|
Christen LA, Piacente S, Mohamed MR, Niles EG. Vaccinia virus early gene transcription termination factors VTF and Rap94 interact with the U9 termination motif in the nascent RNA in a transcription ternary complex. Virology 2008; 376:225-35. [PMID: 18455214 DOI: 10.1016/j.virol.2008.03.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 03/06/2008] [Accepted: 03/26/2008] [Indexed: 10/22/2022]
Abstract
The vaccinia virus core contains a 195 kb double stranded DNA genome, a multi-subunit RNA polymerase, transcription initiation and termination factors and mRNA processing enzymes. Upon infection, vaccinia virus early gene transcription takes place in the virus core. Transcription initiates at early promoters and terminates in response to a termination motif, UUUUUNU, in the nascent mRNA. Early gene transcription termination requires the vaccinia virus termination factor, VTF, a single stranded DNA-dependent ATPase, and NPH I, the Rap94 subunit of the virion RNA polymerase, as well as the presence of the UUUUUNU motif in the nascent RNA. The position of UUUUUNU in the ternary complex suggests that it serves as a site of interaction with one or more components of the transcription termination complex. In order to identify the factor(s) that interact with UUUUUNU a series of direct UV photo crosslinking and ribonuclease A protection studies were undertaken. Through these analyses both VTF and Rap94 were shown to interact with UUUUUNU in the isolated ternary complex. Evidence indicates that the interaction is not mutually exclusive. VTF was shown to bind to UUUUUNU through the N-terminal domain of the large D1 subunit. Furthermore, VTF protects from RNAse A digestion both the 5' region of the nascent transcript as well as a large central component containing UUUUUNU. The addition of an oligonucleotide containing the (5Br)U9 sequence both directly inhibits transcription termination, in vitro and inhibits UV photo crosslinking of VTF to the nascent RNA in the ternary complex. These results support a model in which the availability of the UUUUUNU motif outside of the transcribing RNA polymerase permits binding of both transcription termination factors, VTF and Rap94, to UUUUUNU. The assembly of this termination complex initiates the transcription termination sequence.
Collapse
Affiliation(s)
- Linda A Christen
- Department of Microbiology and Immunology, SUNY School of Medicine, Buffalo, NY 14214, USA
| | | | | | | |
Collapse
|
12
|
Piacente S, Christen L, Dickerman B, Mohamed MR, Niles EG. Determinants of vaccinia virus early gene transcription termination. Virology 2008; 376:211-24. [PMID: 18433825 DOI: 10.1016/j.virol.2008.03.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 03/06/2008] [Accepted: 03/13/2008] [Indexed: 02/07/2023]
Abstract
Vaccinia virus early gene transcription requires the vaccinia termination factor, VTF, nucleoside triphosphate phosphohydrolase I, NPH I, ATP, the virion RNA polymerase, and the motif, UUUUUNU, in the nascent RNA, found within 30 to 50 bases from the poly A addition site, in vivo. In this study, the relationships among the vaccinia early gene transcription termination efficiency, termination motif specificity, and the elongation rate were investigated. A low transcription elongation rate maximizes termination efficiency and minimizes specificity for the UUUUUNU motif. Positioning the termination motif over a 63 base area upstream from the RNA polymerase allowed efficient transcript release, demonstrating a remarkable plasticity in the transcription termination complex. Efficient transcript release was observed during ongoing transcription, independent of VTF or UUUUUNU, but requiring both NPH I and either ATP or dATP. This argues for a two step model: the specifying step, requiring both VTF and UUUUUNU, and the energy-dependent step employing NPH I and ATP. Evaluation of NPH I mutants for the ability to stimulate transcription elongation demonstrated that ATPase activity and a stable interaction between NPH I and the Rap94 subunit of the viral RNA polymerase are required. These observations demonstrate that NPH I is a component of the elongating RNA polymerase, which is catalytically active during transcription elongation.
Collapse
Affiliation(s)
- Sarah Piacente
- Department of Microbiology and Immunology, SUNY School of Medicine and Biomedical Sciences, Buffalo, NY, 14214-3200, USA
| | | | | | | | | |
Collapse
|
13
|
Silva P, Soares J, Brasil B, Nogueira S, Andrade A, de Magalhães J, Bonjardim M, Ferreira P, Kroon E, Bruna-Romero O, Bonjardim C. Differential role played by the MEK/ERK/EGR-1 pathway in orthopoxviruses vaccinia and cowpox biology. Biochem J 2006; 398:83-95. [PMID: 16686604 PMCID: PMC1525012 DOI: 10.1042/bj20060509] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Appropriation of signalling pathways facilitates poxvirus replication. Poxviruses, as do most viruses, try to modify the host cell environment to achieve favourable replication conditions. In the present study, we show that the early growth response 1 gene (egr-1) is one of the host cell factors intensely modulated by the orthopoxviruses VV (vaccinia virus) and CPV (cowpox virus). These viruses stimulated the generation of both egr-1 mRNA and its gene product, throughout their entire replication cycles, via the requirement of MEK [mitogen-activated protein kinase/ERK (extracellular-signal-regulated kinase) kinase]/ERK pathway. We showed that, upon VV infection, EGR-1 translocates into the nucleus where it binds to the EBS (egr-1-binding site) positioned at the 5' region of EGR-1-regulated genes. In spite of both viruses belonging to the same genus, several lines of evidence, however, revealed a remarkable contrast between them as far as the roles played by the MEK/ERK/EGR-1 pathway in their biological cycles are concerned. Hence (i) the knocking-down of egr-1 by siRNA (small interfering RNA) proved that this transcription factor is of critical relevance for VV biology, since a decrease of about one log cycle in virus yield was verified, along with a small virus plaque phenotype, whereas the gene silencing did not have a detrimental effect on either CPV multiplication or viral plaque size; (ii) while both pharmacological and genetic inhibition of MEK/ERK resulted in a significant decrease in VV yield, both approaches had no impact on CPV multiplication; and (iii) CPV DNA replication was unaffected by pharmacological inhibition of MEK/ERK, but phosphorylation of MEK/ERK was dependent on CPV DNA replication, contrasting with a significant VV DNA inhibition and VV DNA replication-independence to maintain ERK1/2 phosphorylation, observed under the same conditions.
Collapse
Affiliation(s)
- Patrícia N. G. Silva
- *Grupo de Transdução de Sinal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Jamária A. P. Soares
- *Grupo de Transdução de Sinal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Bruno S. A. F. Brasil
- *Grupo de Transdução de Sinal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Sarah V. Nogueira
- *Grupo de Transdução de Sinal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Anderson A. Andrade
- *Grupo de Transdução de Sinal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - José C. de Magalhães
- *Grupo de Transdução de Sinal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Marisa B. Bonjardim
- ‡Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Paulo C. P. Ferreira
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Erna G. Kroon
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Oscar Bruna-Romero
- §Laboratório de Agentes Recombinantes, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
| | - Cláudio A. Bonjardim
- *Grupo de Transdução de Sinal, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- †Laboratório de Vírus, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
- To whom correspondence should be addressed (email )
| |
Collapse
|
14
|
Mohamed MR, Piacente SC, Dickerman B, Niles EG. Effect of UTP sugar and base modifications on vaccinia virus early gene transcription. Virology 2006; 349:359-70. [PMID: 16460779 DOI: 10.1016/j.virol.2006.01.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Revised: 12/03/2005] [Accepted: 01/03/2006] [Indexed: 11/23/2022]
Abstract
Prior efforts demonstrated that RNA oligonucleotides containing the transcription termination signal UUUUUNU stimulate premature termination of vaccinia virus early gene transcription, in vitro. This observation suggests that viral transcription termination may be an attractive target for the development of anti-poxvirus agents. Since short RNA molecules are readily susceptible to nuclease digestion, their use would require stabilizing modifications. In order to evaluate the effect of both ribose and uracil modifications of the U5NU signal on early gene transcription termination, UTP derivatives harboring modifications to the uracil base, the 2' position of the ribose sugar and the phosphodiester bond were examined in an in vitro vaccinia virus early gene transcription termination system. Incorporation of 4-S-U, 5-methyl-U, 2-S-U, pseudo U and 2'-F-dU into the nascent transcript inhibited transcription termination. 6-aza-U, 2'-amino-U, 2'-azido-U and 2'-O methyl-U inhibited transcription elongation resulting in the accumulation of short transcripts. The majority of the short transcripts remained in the ternary complex and could be chased into full-length transcripts. Initially, derivatives of all uridines in the termination signal were tested. Partial modification of the termination signal reduced termination activity, as well. Introduction of 2'-O methyl ribose to the first three uridines of the U9 termination signal reduced the ability of U9 containing oligonucleotides to stimulate in vitro transcription termination, in trans. Further modifications eliminated this activity. Thus, viral early gene transcription termination demonstrates a rigorous requirement for a U5NU signal that is unable to tolerate modification to the base or sugar. Additionally, VTF was shown to enhance transcription elongation through the T9 sequence in the template. These results suggest that VTF may play a subtle role in early gene transcription elongation in addition to its known function in mRNA cap formation, early gene transcription termination and intermediate gene transcription initiation.
Collapse
Affiliation(s)
- Mohamed Ragaa Mohamed
- Department of Biochemistry, Witebsky Center for Microbial Pathogenesis and Immunology, State University of New York, School of Medicine and Biomedical Sciences, Buffalo, NY 14214, USA
| | | | | | | |
Collapse
|
15
|
Prins C, Cresawn SG, Condit RC. An isatin-beta-thiosemicarbazone-resistant vaccinia virus containing a mutation in the second largest subunit of the viral RNA polymerase is defective in transcription elongation. J Biol Chem 2004; 279:44858-71. [PMID: 15294890 DOI: 10.1074/jbc.m408167200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The vaccinia virus RNA polymerase is a multi-subunit enzyme that contains eight subunits in the postreplicative form. A prior study of a virus called IBT(r90), which contains a mutation in the A24 gene encoding the RPO132 subunit of the RNA polymerase, demonstrated that the mutation results in resistance to the anti-poxvirus drug isatin-beta-thiosemicarbazone (IBT). In this study, we utilized an in vitro transcription elongation assay to determine the effect of this mutation on transcription elongation. Both wild type and IBT(r90) polymerase complexes were studied with regard to their ability to pause during elongation, their stability in a paused state, their ability to release transcripts, and their elongation rate. We have determined that the IBT(r90) complex is specifically defective in elongation compared with the WT complex, pausing longer and more frequently than the WT complex. We have built a homology model of the RPO132 subunit with the yeast pol II rpb2 subunit to propose a structural mechanism for this elongation defect.
Collapse
Affiliation(s)
- Cindy Prins
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32610-0266, USA
| | | | | |
Collapse
|
16
|
Mohamed MR, Niles EG. UUUUUNU oligonucleotide inhibition of RNA synthesis in vaccinia virus cores. Virology 2004; 324:493-500. [PMID: 15207634 DOI: 10.1016/j.virol.2004.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2004] [Revised: 03/24/2004] [Accepted: 04/01/2004] [Indexed: 11/15/2022]
Abstract
Recent results from this laboratory demonstrated the ability of U5NU-containing oligonucleotides to stimulate premature termination of early gene transcription in vitro. Further studies on the oligonucleotide sequence and structural requirements for stimulating premature termination demonstrated that only oligonucleotides possessing ribouracil U9 with a phosphodiester linkage are active. Because an oligonucleotide as short as 9 bases serves as an effective stimulator of premature transcription termination, we reasoned that short U5NU-containing oligonucleotides might serve as efficacious anti-poxvirus agents because they would prevent the synthesis of full-sized early mRNA. To be useful in vivo, the oligonucleotides must not only be taken up by the infected cells, but also be able to enter the virus core, the site of early gene transcription, and retain their ability to stimulate premature termination. The ability of U9-containing oligonucleotides to inhibit virus core RNA synthesis was evaluated. The U5NU oligonucleotides exhibited a dramatic sequence-specific inhibition of core RNA synthesis, consistent with their ability to stimulate premature termination of early gene transcription. Moreover, the concentration of U5NU oligonucleotide required to exhibit half maximal inhibition of RNA synthesis was found to be less for a 9 mer RNA than it was for a 17 or 22 mer RNA. This suggests the possibility that the smaller oligonucleotides may have easier access to the core. This observation lends support to the notion that such oligonucleotides might serve as effective anti-poxvirus therapeutic agents.
Collapse
Affiliation(s)
- Mohamed Ragaa Mohamed
- Department of Biochemistry, School of Medicine and Biomedical Sciences, State University of New York, Buffalo, NY 14214, USA
| | | |
Collapse
|
17
|
Nalçacioğlu R, Marks H, Vlak JM, Demirbaĝ Z, van Oers MM. Promoter analysis of the Chilo iridescent virus DNA polymerase and major capsid protein genes. Virology 2003; 317:321-9. [PMID: 14698670 DOI: 10.1016/j.virol.2003.08.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The DNA polymerase (DNApol) and major capsid protein (MCP) genes were used as models to study promoter activity in Chilo iridescent virus (CIV). Infection of Bombyx mori SPC-BM-36 cells in the presence of inhibitors of DNA or protein synthesis showed that DNApol, as well as helicase, is an immediate-early gene and confirmed that the major capsid protein (MCP) is a late gene. Transcription of DNApol initiated 35 nt upstream and that of MCP 14 nt upstream of the translational start site. In a luciferase reporter gene assay both promoters were active only when cells were infected with CIV. For DNApol sequences between position -27 and -6, relative to the transcriptional start site, were essential for promoter activity. Furthermore, mutation of a G within the sequence TTGTTTT located just upstream of the DNApol transcription initiation site reduced the promoter activity by 25%. Sequences crucial for MCP promoter activity are located between positions -53 and -29.
Collapse
Affiliation(s)
- Remziye Nalçacioğlu
- Laboratory of Virology, Wageningen University, Binnenhaven 11, 6709 PD, Wageningen, The Netherlands
| | | | | | | | | |
Collapse
|
18
|
Mohamed MR, Niles EG. UUUUUNU oligonucleotide stimulation of vaccinia virus early gene transcription termination, in trans. J Biol Chem 2003; 278:11794-801. [PMID: 12556520 DOI: 10.1074/jbc.m213263200] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Vaccinia virus early gene transcription termination requires the vaccinia termination factor (VTF), NPH I, a single stranded DNA-dependent ATPase, the virion form of RNA polymerase containing the Rap 94 subunit, and the signal UUUUUNU, which resides in the nascent mRNA, located 30 to 50 bases upstream from the poly(A) addition site. Evidence indicates that a required termination factor acts through binding to the UUUUUNU signal. To further investigate the function of UUUUUNU, the ability of UUUUUNU containing oligonucleotides to inhibit transcription termination was tested. A 22-mer RNA oligonucleotide containing a central U9 sequence exhibited sequence and concentration-dependent stimulation of premature transcription termination and transcript release, in trans. Activation of premature termination required VTF, NPH I, Rap 94, and ATP, demonstrating that the normal termination machinery was employed. Premature termination was not stimulated by RNA harboring a mutant UUUUUNU, demonstrating specificity. These data are consistent with a model in which a required termination factor is converted from an inactive to an active form by binding to a UUUUUNU containing oligonucleotide. The active termination factor then interacts with the ternary complex stimulating transcription termination through the normal mechanism, independent of the nascent mRNA sequence.
Collapse
Affiliation(s)
- Mohamed Ragaa Mohamed
- Department of Microbiology, State University of New York, School of Medicine and Biomedical Sciences, Buffalo, New York 14214, USA
| | | |
Collapse
|
19
|
Condit RC, Niles EG. Regulation of viral transcription elongation and termination during vaccinia virus infection. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1577:325-36. [PMID: 12213661 DOI: 10.1016/s0167-4781(02)00461-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Vaccinia virus provides a useful genetic and biochemical tool for studies of the basic mechanisms of eukaryotic transcription. Vaccinia genes are transcribed in three successive gene classes during infection, early, intermediate, and late. Vaccinia transcription is regulated primarily by virus gene products not only during initiation, but also during elongation and termination. The factors and mechanisms regulating early elongation and termination differ from those regulating intermediate and late gene expression. Control of transcription elongation and termination in vaccinia virus bears some similarity to the same process in other prokaryotic and eukaryotic systems, yet features some novel mechanisms as well.
Collapse
Affiliation(s)
- Richard C Condit
- Department of Molecular Genetics and Microbiology, P.O. Box 100266, University of Florida, Gainesville, FL 32610, USA.
| | | |
Collapse
|
20
|
Srinivasan V, Schnitzlein WM, Tripathy DN. Fowlpox virus encodes a novel DNA repair enzyme, CPD-photolyase, that restores infectivity of UV light-damaged virus. J Virol 2001; 75:1681-8. [PMID: 11160666 PMCID: PMC114077 DOI: 10.1128/jvi.75.4.1681-1688.2001] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fowlpox virus (FPV), a pathogen of poultry, can persist in desiccated scabs shed from infected hosts. Although the mechanisms which ensure virus survival are unknown, it is likely that some type of remedial action against environmentally induced damage is required. In this regard, we have identified an open reading frame (ORF) coding for a putative class II cyclobutane pyrimidine dimer (CPD)-photolyase in the genome of FPV. This enzyme repairs the UV light-induced formation of CPDs in DNA by using blue light as an energy source and thus could enhance the viability of FPV during its exposure to sunlight. Based on transcriptional analyses, the photolyase gene was found to be expressed late during the FPV replicative cycle. That the resultant protein retained DNA repair activity was demonstrated by the ability of the corresponding FPV ORF to complement functionally a photolyase-deficient Escherichia coli strain. Interestingly, insertional inactivation of the FPV photolyase gene did not impair the replication of such a genetically altered virus in cultured cells. However, greater sensitivity of this mutant than of the parental virus to UV light irradiation was evident when both were subsequently photoreactivated in the absence of host participation. Therefore, FPV appears to incorporate its photolyase into mature virions where the enzyme can promote their survival in the environment. Although expression of a homologous protein has been predicted for some chordopoxviruses, this report is the first to demonstrate that a poxvirus can utilize light to repair damage to its genome.
Collapse
Affiliation(s)
- V Srinivasan
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Illinois, Urbana, Illinois 61802, USA
| | | | | |
Collapse
|
21
|
Mohamed MR, Latner DR, Condit RC, Niles EG. Interaction between the J3R subunit of vaccinia virus poly(A) polymerase and the H4L subunit of the viral RNA polymerase. Virology 2001; 280:143-52. [PMID: 11162828 DOI: 10.1006/viro.2000.0749] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
J3R, the 39-kDa subunit of vaccinia virus poly(A) polymerase, is a multifunctional protein that catalyzes (nucleoside-2'-O-)-methyltransferase activity, serves as a poly(A) polymerase stimulatory factor, and acts as a postreplicative positive transcription elongation factor. Prior results support an association between poly(A) polymerase and the virion RNA polymerase. A possible direct interaction between J3R and H4L subunit of virion RNA polymerase was evaluated. J3R was shown to specifically bind to H4L amino acids 235-256, C terminal to NPH I binding site on H4L. H4L binds to the C-terminal region of J3R between amino acids 169 and 333. The presence of a J3R binding site near to the NPH I binding region on H4L led us to evaluate a physical interaction between NPH I and J3R. The NPH I binding site was located on J3R between amino acids 169 and 249, and J3R was shown to bind to NPH I between amino acids 457 and 524. To evaluate a role for J3R in early gene mRNA synthesis, transcription termination, and/or release, a transcription-competent extract prepared from cells infected with mutant virus lacking J3R, J3-7. Analysis of transcription activity demonstrated that J3R is not required for early mRNA synthesis and is not an essential factor in early gene transcription termination or transcript release in vitro. J3R interaction with NPH I and H4L may serve as a docking site for J3R on the virion RNA polymerase, linking transcription to mRNA cap formation and poly(A) addition.
Collapse
Affiliation(s)
- M R Mohamed
- Department of Biochemistry, SUNY School of Medicine and Biomedical Science at Buffalo, Buffalo, New York 14214, USA
| | | | | | | |
Collapse
|
22
|
Hayakawa T, Kojima K, Nonaka K, Nakagaki M, Sahara K, Asano SI, Iizuka T, Bando H. Analysis of proteins encoded in the bipartite genome of a new type of parvo-like virus isolated from silkworm - structural protein with DNA polymerase motif. Virus Res 2000; 66:101-8. [PMID: 10653921 DOI: 10.1016/s0168-1702(99)00129-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Bombyx mori densonucleosis virus type 2 (BmDNV-2) is a small, spherical virus containing two complementary single-stranded linear DNA molecules (VD1, VD2). BmDNV-2 is a new type of virus with a unique, yet unspecified replication mechanism which is different from that of parvoviruses (Bando, H., Choi, H., Ito, Y., Nakagaki, M. , Kawase, S., 1992. Structural analysis on the single-stranded genomic DNAs of the virus newly isolated from silkworm: the DNA molecules share a common terminal sequence, Arch. Virol. 124, 187-193; Bando, H., Hayakawa, T., Asano, S., Sahara, K., Nakagaki, M. , Iizuka, T., 1995. Analysis of the genetic information of a DNA segment of a new virus from silkworm, Arch. Virol., 140, 1147-1155; Hayakawa, T., Asano, S., Sahara, K., Iizuka, T., Bando, H., 1997. Detection of replicative intermediate with closed terminus of Bombyx densonucleosis virus. Arch. Virol. 142, 1-7). Recent analyses on the genomic information of BmDNV-2 identified open reading frames which code for three tentative nonstructural proteins and four (VP1 to 4) of the six known structural proteins (Bando, H., Hayakawa, T., Asano, S., Sahara, K., Nakagaki, M., Iizuka, T., 1995. Analysis of the genetic information of a DNA segment of a new virus from silkworm, Arch. Virol., 140, 1147-1155; Nakagaki et al., in preparation). In this report we demonstrate that the two largest ORFs, VD1-ORF1 and VD2-ORF1, code for the two remaining structural proteins. In addition, computer-assisted analysis revealed that the structural protein encoded in VD1-ORF1 contains sequences conserved among various DNA polymerases, and showed an evolutionary relationship with the DNA polymerases involved in protein-primed replication.
Collapse
Affiliation(s)
- T Hayakawa
- Division of Applied Bioscience, Faculty of Agriculture, Hokkaido University, Sapporo 060, Hokkaido, Japan
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Katsafanas GC, Moss B. Histidine codons appended to the gene encoding the RPO22 subunit of vaccinia virus RNA polymerase facilitate the isolation and purification of functional enzyme and associated proteins from virus-infected cells. Virology 1999; 258:469-79. [PMID: 10366585 DOI: 10.1006/viro.1999.9744] [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: 11/22/2022]
Abstract
Vaccinia virus encodes a eukaryotic-like RNA polymerase composed of two large and six small subunit protein species. A replication-competent virus with 10 histidine codons added to the single endogenous J4R open reading frame was constructed. The altered migration of the 22-kDa subunit of RNA polymerase on SDS-polyacrylamide gel electrophoresis confirmed that J4R encoded the RPO22 subunit and that the mutant virus was genetically stable. The histidine-tagged RNA polymerase bound quantitatively to metal-affinity resins and was eluted in an active form upon addition of imidazole. Glycerol gradient sedimentation of the eluted fraction indicated that most of the RPO22 in infected cells is associated with RNA polymerase. Using stringent washing conditions, metal-affinity chromatography resulted in a several hundred-fold increase in RNA-polymerase-specific activity, and substantially pure enzyme was obtained with an additional conventional chromatography step. When mild conditions were used for washing the metal-affinity resin, the vaccinia virus-encoded capping enzyme, early transcription factor, and nucleoside triphosphate phosphohydrolase I specifically co-eluted with the tagged RNA polymerase, consistent with their physical association. The ability to selectively bind RNA polymerase to an affinity column provided a simple and rapid method of concentrating and purifying active enzyme and protein complexes.
Collapse
Affiliation(s)
- G C Katsafanas
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, 20892-0445, USA
| | | |
Collapse
|
24
|
Engleka KA, Lewis EW, Howard BH. Mechanisms of replication-deficient vaccinia virus/T7 RNA polymerase hybrid expression: effect of T7 RNA polymerase levels and alpha-amanitin. Virology 1998; 243:331-9. [PMID: 9568032 DOI: 10.1006/viro.1998.9070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Components of the eukaryotic vaccinia virus/T7 RNA polymerase hybrid expression system were assessed using recombinant and nonrecombinant forms of modified vaccinia Ankara (MVA), a replication-deficient vaccinia virus strain. Recombinant MVA virus expressing T7 RNA polymerase (Wyatt, L. S., Moss, B., and Rozenblatt, S. (1995). Virology 210, 202-205) stimulated high levels of expression from a T7 promoter-chloramphenicol acetyltransferase (CAT) reporter. Most, but not all, of the virally induced expression was T7 RNA polymerase and T7 promoter dependent, with no viral enhancement of translation of T7 transcripts. The efficacy of supplying T7 RNA polymerase expression from nonviral sources was evaluated using a self-amplifying T7 RNA polymerase autogene or an inducible T7 RNA polymerase expression vector. The latter modes yielded CAT activity dependent on T7 RNA polymerase expression; however, expression required viral factors independent of T7 RNA polymerase and did not reach that attained using the recombinant virus. In further experiments, MVA-induced T7 RNA polymerase expression was upregulated by alpha-amanitin, an inhibitor of eukaryotic polymerases. This indicates that MVA/T7 RNA polymerase hybrid expression may be rendered still more efficient by ameliorating transcriptional interference due to an alpha-amanitin-sensitive eukaryotic factor(s).
Collapse
Affiliation(s)
- K A Engleka
- Laboratory of Molecular Growth Regulation, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-2753, USA.
| | | | | |
Collapse
|
25
|
Hassett DE, Lewis JI, Xing X, DeLange L, Condit RC. Analysis of a temperature-sensitive vaccinia virus mutant in the viral mRNA capping enzyme isolated by clustered charge-to-alanine mutagenesis and transient dominant selection. Virology 1997; 238:391-409. [PMID: 9400612 DOI: 10.1006/viro.1997.8820] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have previously reported the successful development of a targeted genetic method for the creation of temperature-sensitive vaccinia virus mutants [D. E. Hassett and R. C. Condit (1994) Proc. Natl. Acad. Sci. USA 91, 4554-4558]. This method has now been applied to the large subunit of the multifunctional vaccinia virus capping enzyme, encoded by gene D1R. Ten clustered charge-to-alanine mutations were created in a cloned copy of D1R. Four of these mutations were successfully transferred into the viral genome using transient dominant selection, and each of these four mutations yielded viruses with plaque phenotypes different from that of wild-type virus. Two of the mutant viruses, 516 and 793, were temperature sensitive in a plaque assay. Mutant 793 was also temperature sensitive in a one-step growth experiment. Phenotypic characterization of the 793 virus under both permissive and nonpermissive conditions revealed nearly normal patterns of viral protein and mRNA synthesis. Under nonpermissive conditions the 793 virus was defective in telomere resolution and blocked at an intermediate stage of viral morphogenesis. In vitro assays of various capping enzyme activities revealed that in permeabilized virions, enzyme guanylylate intermediate formation was reduced and methyltransferase activity was thermolabile, while in solubilized virion extracts enzyme guanylylate activity was reduced and both guanylyltransferase and methyltransferase activities were absent. Thus, the 793 mutation affects at least two separate enzymatic activities of the capping enzyme, guanylyltransferase and methyltransferase, and when incorporated into the virus genome, the mutation yields a virus that is temperature sensitive for growth, telomere resolution, and virion morphogenesis.
Collapse
Affiliation(s)
- D E Hassett
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville 32610, USA
| | | | | | | | | |
Collapse
|
26
|
Hu X, Carroll LJ, Wolffe EJ, Moss B. De novo synthesis of the early transcription factor 70-kilodalton subunit is required for morphogenesis of vaccinia virions. J Virol 1996; 70:7669-77. [PMID: 8892887 PMCID: PMC190836 DOI: 10.1128/jvi.70.11.7669-7677.1996] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Vaccinia virus early transcription factor (VETF) is a heterodimeric protein that is packaged in virus particles for expression of early genes during the next round of infection. To investigate additional roles of VETF, we constructed a conditionally lethal recombinant vaccinia virus in which the D6R gene, encoding the 70-kDa subunit of VETF, is under stringent Escherichia coli lac operator control. When cells were infected with the recombinant virus in the absence of an inducer, synthesis of the 70-kDa protein was undetectable and the yield of infectious virus was severely reduced. Under these nonpermissive conditions, DNA replication and synthesis of viral proteins other than the one encoded by D6R occurred, suggesting that de novo synthesis of VETF is not required for expression of early or late genes during the virus growth cycle. Electron microscopy, however, revealed that immature virus particles and masses of electron-dense material accumulated in the absence of an inducer. We concluded that VETF has a direct role in virion morphogenesis or is required for expression of a novel subset of genes that have such a role.
Collapse
Affiliation(s)
- X Hu
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892-0445, USA
| | | | | | | |
Collapse
|
27
|
Kovacs GR, Moss B. The vaccinia virus H5R gene encodes late gene transcription factor 4: purification, cloning, and overexpression. J Virol 1996; 70:6796-802. [PMID: 8794318 PMCID: PMC190724 DOI: 10.1128/jvi.70.10.6796-6802.1996] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The vaccinia virus late stage-specific transcription factor P3 was purified to homogeneity from HeLa cells that were infected in the presence of an inhibitor of viral DNA replication. The purified 36-kDa protein was digested with trypsin, and the peptides were analyzed by mass spectroscopy and amino-terminal sequencing. The purified factor was identified as the product of the vaccinia virus H5R open reading frame by both methods. A recombinant baculovirus was engineered to express the H5R open reading frame. The partially purified recombinant protein could replace the vaccinia virus P3 factor in transcription assays. On the basis of these findings, we assigned the H5R gene product the name viral late gene transcription factor 4 (VLTF-4). Unlike VLTF-1, -2, and -3, which are synthesized exclusively after viral DNA replication, VLTF-4 is synthesized before and after viral DNA synthesis. Indirect immunofluorescence of infected cells with anti-H5R protein antiserum demonstrated that VLTF-4 is diffusely distributed in the cytoplasm when DNA replication is blocked but is localized to discrete viral DNA-containing factories during a productive infection. Its expression pattern and subcellular distribution suggest that the H5R gene product may have multiple roles in the viral life cycle.
Collapse
Affiliation(s)
- G R Kovacs
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892, USA
| | | |
Collapse
|
28
|
Passarelli AL, Kovacs GR, Moss B. Transcription of a vaccinia virus late promoter template: requirement for the product of the A2L intermediate-stage gene. J Virol 1996; 70:4444-50. [PMID: 8676468 PMCID: PMC190378 DOI: 10.1128/jvi.70.7.4444-4450.1996] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Evidence is presented that a 26-kDa protein encoded by the vaccinia virus A2L open reading frame, originally shown to be one of three intermediate-stage genes that together can transactivate late-stage gene expression in transfection assays (J. G. Keck, C. J. Baldick, and B. Moss, Cell 61:801-809, 1990), is required for in vitro transcription of a template with a late promoter. The critical step in this analysis was the preparation of an extract containing all the required factors except for the A2L protein. This extract was prepared from cells infected with a recombinant vaccinia virus expressing the bacteriophage T7 RNA polymerase in the presence of the DNA synthesis inhibitor cytosine arabinoside and transfected with plasmids containing the two other known transactivator genes, A1L and G8R, under T7 promoter control. Reaction mixtures made with extracts of these cells had background levels of late transcription activity, unless they were supplemented with extracts of cells transfected with the A2L gene. Active transcription mixtures were also made by mixing extracts from three sets of cells, each transfected with a gene (A1L, A2L, or G8R) encoding a separate factor, indicating the absence of any requirement for their coexpression. To minimize the possibility that the A2L protein functions indirectly by activating another viral or cellular protein, this gene was expressed in insect cells by using a baculovirus vector. The partially purified recombinant protein complemented the activity of A2L-deficient cell extracts. Recombinant A1L, A2L, and G8R proteins, all produced in insect cells, together complemented extracts from mammalian cells containing only viral early proteins, concordant with previous in vivo transfection data.
Collapse
Affiliation(s)
- A L Passarelli
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892, USA
| | | | | |
Collapse
|
29
|
Gershon P, Moss B. Expression, purification, and characterization of vaccinia virus-encoded RNA and poly(A) polymerases. Methods Enzymol 1996; 275:208-27. [PMID: 9026640 DOI: 10.1016/s0076-6879(96)75014-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- P Gershon
- Department of Biochemistry and Biophysics, Institute of Biosciences and Technology, Texas A&M University, College Station 77843, USA
| | | |
Collapse
|
30
|
Kane EM, Shuman S. Adenosine N1-oxide inhibits vaccinia virus replication by blocking translation of viral early mRNAs. J Virol 1995; 69:6352-8. [PMID: 7666536 PMCID: PMC189534 DOI: 10.1128/jvi.69.10.6352-6358.1995] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Adenosine N1-oxide (ANO) is a potent and highly selective inhibitor of vaccinia virus replication. We examined the impact of ANO on vaccinia virus macromolecular synthesis during synchronous infection of BSC40 cells. Viral DNA replication and viral late protein synthesis were blocked completely by ANO, effects that were attributable to a defect in the expression of viral early genes. Vaccinia virus early proteins were not synthesized in the presence of ANO, even though vaccinia virus early mRNAs were produced. Cellular protein synthesis was unaffected by ANO, and virus infection in the presence of the drug did not elicit the normal shutoff of host protein synthesis. Adenosine N1-oxide triphosphate (ANO-TP), the predominant metabolite of the drug in vivo, could substitute for ATP in RNA synthesis by purified vaccinia virus RNA polymerase. ANO-TP could support early transcription by purified virions if dATP was provided as an energy source. ANO-TP did not inhibit early transcription in the presence of ATP. These findings suggest a novel antiviral mechanism whereby incorporation of a modified nucleotide into viral mRNAs might selectively block viral gene expression at the level of translation. We believe that ANO merits consideration as an antipoxvirus drug for topical treatment of molluscum contagiosum in humans.
Collapse
Affiliation(s)
- E M Kane
- Program in Molecular Biology, Sloan-Kettering Institute, New York, New York 10021, USA
| | | |
Collapse
|
31
|
Simpson DA, Condit RC. The vaccinia virus A18R protein plays a role in viral transcription during both the early and the late phases of infection. J Virol 1994; 68:3642-9. [PMID: 8189502 PMCID: PMC236868 DOI: 10.1128/jvi.68.6.3642-3649.1994] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The vaccinia virus gene A18R is essential for virus infection. The loss of A18R protein function results in unregulated transcription late during virus infection from regions of the viral genome which are normally transcriptionally quiescent. We have characterized A18R protein expression in cells infected with wild-type virus and the A18R temperature-sensitive mutant Cts23. The A18R protein is expressed during early and late phases of infection. The A18R protein expressed by Cts23 virus at permissive and nonpermissive temperatures is significantly less stable than the wild-type A18R protein. The A18R protein was identified as a virion component and localized by detergent extraction to the virion core. Virions purified from cells infected with the A18R temperature-sensitive mutants Cts4, Cts22, and Cts23 are defective in early viral transcription in vitro. The mutant transcription defect is not attributable to gross defects in virion structure or virion DNA-dependent RNA polymerase activity. We conclude that the A18R protein plays a role in viral transcription during the early phase of infection as well as during the late phase.
Collapse
Affiliation(s)
- D A Simpson
- Department of Immunology and Medical Microbiology, University of Florida, Gainesville 32610-0266
| | | |
Collapse
|
32
|
Rosales R, Harris N, Ahn B, Moss B. Purification and identification of a vaccinia virus-encoded intermediate stage promoter-specific transcription factor that has homology to eukaryotic transcription factor SII (TFIIS) and an additional role as a viral RNA polymerase subunit. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36783-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
33
|
The mRNA (guanine-7-)methyltransferase domain of the vaccinia virus mRNA capping enzyme. Expression in Escherichia coli and structural and kinetic comparison to the intact capping enzyme. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36562-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
34
|
Hagler J, Luo Y, Shuman S. Factor-dependent transcription termination by vaccinia RNA polymerase. Kinetic coupling and requirement for ATP hydrolysis. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36989-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
35
|
Ahn B, Gershon P, Moss B. RNA polymerase-associated protein Rap94 confers promoter specificity for initiating transcription of vaccinia virus early stage genes. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37322-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
36
|
The vaccinia virus mRNA (guanine-N7-)-methyltransferase requires both subunits of the mRNA capping enzyme for activity. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42021-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
37
|
Hagler J, Shuman S. Ternary complex formation by vaccinia virus RNA polymerase at an early viral promoter: analysis by native gel electrophoresis. J Virol 1992; 66:2982-9. [PMID: 1373199 PMCID: PMC241057 DOI: 10.1128/jvi.66.5.2982-2989.1992] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have resolved, by native gel electrophoresis, two intermediates in the transcription of a vaccinia virus early gene by the virus-encoded RNA polymerase. Polymerase holoenzyme containing the vaccinia virus early transcription factor (VETF) forms a complex of VETF bound to the promoter as the first step in a pathway leading to establishment of a committed ternary elongation complex. Formation of the VETF-DNA complex is stimulated by magnesium but is uninfluenced by nucleoside triphosphates. A stable binary complex of RNA polymerase bound to DNA is not detected. Assembly of a gel-stable polymerase-DNA complex depends on conditions permissive for RNA synthesis. Nucleotide omission experiments suggest that at least a tetrameric RNA must be made before a ternary complex is stabilized. RNA analysis indicates that complexes containing nascent transcripts 20 nucleotides long are stable and active. Ternary complex formation requires hydrolyzable ATP. This is consistent with an essential role for the ATPase activity of VETF at a step subsequent to DNA binding, as proposed by Broyles (S. S. Broyles, J. Biol. Chem. 266:15545-15548, 1991). The ternary complex, once formed, is resistant to dissociation by competitor DNA, as well as by salt, Sarkosyl, and heparin. The effects of these inhibitory agents on transcription complex formation suggest that they target different steps in the assembly pathway.
Collapse
Affiliation(s)
- J Hagler
- Program in Molecular Biology, Sloan-Kettering Institute, New York, New York 10021
| | | |
Collapse
|
38
|
Broyles S. A role for ATP hydrolysis in vaccinia virus early gene transcription. Dissociation of the early transcription factor-promoter complex. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)98651-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
39
|
Broyles S, Li J, Moss B. Promoter DNA contacts made by the vaccinia virus early transcription factor. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)98650-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
40
|
Discrete functional stages of vaccinia virus early transcription during a single round of RNA synthesis in vitro. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)98839-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
41
|
Dyster LM, Niles EG. Genetic and biochemical characterization of vaccinia virus genes D2L and D3R which encode virion structural proteins. Virology 1991; 182:455-67. [PMID: 2024484 DOI: 10.1016/0042-6822(91)90586-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Polyclonal antisera raised against fusion proteins containing portions of the vaccinia virus D2L and D3R proteins were prepared. Immunoprecipitation of pulse-labeled infected cell extracts and Western blot analysis demonstrated that genes D2L and D3R encode 16.9- and 27-kDa proteins, respectively. Both are synthesized late during infection and there is no evidence for proteolytic processing of either protein. Western blots of purified virus and subvirion fractions showed that D2L and D3R are virion components, residing in a detergent-insoluble fraction, containing viral core structural proteins. Trypsin sensitivity experiments suggest that each is found in an equivalent position within the virus core. Pulse-chase analysis showed that both proteins exhibit biphasic stability in which an unstable nascent component is replaced by a stable form. This observation suggests that the stable component results from the insertion of D2L and D3R into an immature core structure. The DNA sequence of four ts mutants previously mapped to genes D2L and D3R is reported. Analysis of the ability of each mutant to synthesize and process viral proteins showed that protein synthetic patterns were indistinguishable from wild type, however, three of the four mutants were defective in the processing of the major virion structural precursor, p4a. Unlike the biphasic stability observed in wild-type infected cells, D2L and D3R were totally degraded in cells infected at 40 degrees with any of the four ts mutants. Stability of the D2L and D3R proteins, in cells treated with rifampicin, is unaffected which demonstrates that a block in morphogenesis is not directly responsible for the observed instability of the mutant proteins.
Collapse
Affiliation(s)
- L M Dyster
- Department of Biochemistry, School of Medicine and Biomedical Sciences, State University of New York, Buffalo 14214
| | | |
Collapse
|
42
|
Moussatche N, Keller SJ. Phosphorylation of vaccinia virus core proteins during transcription in vitro. J Virol 1991; 65:2555-61. [PMID: 2016772 PMCID: PMC240612 DOI: 10.1128/jvi.65.5.2555-2561.1991] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The phosphorylation of vaccinia virus core proteins has been studied in vitro during viral transcription. The incorporation of [gamma-32P]ATP into protein is linear for the first 2 min of the reaction, whereas incorporation of [3H]UTP into RNA lags for 1 to 2 min before linear synthesis. At least 12 different proteins are phosphorylated on autoradiograms of acrylamide gels, and the majority of label is associated with low-molecular-weight proteins. If the transcription reaction is reduced by dropping the pH to 7 from its optimal of 8.5, two proteins (70 and 80 kDa) are no longer phosphorylated. RNA isolated from the pH 7 transcription reaction hybridized primarily to the vaccinia virus HindIII DNA fragments D to F, whereas the transcripts synthesized at pH 8.5 hybridized to almost all of the HindIII-digested vaccinia virus DNA fragments. The differences between the pH 7.0 and 8.5 transcription reactions in phosphorylation and transcription could be eliminated by preincubating the viral cores with 2 mM ATP. In sum, the results suggest that the phosphorylation of the 70- and 80-kDa peptides may contribute to the regulation of early transcription.
Collapse
Affiliation(s)
- N Moussatche
- Instituto de Biofisica Carlos Chagas Filho, Rio de Janeiro, Brazil
| | | |
Collapse
|
43
|
Vos JC, Sasker M, Stunnenberg HG. Promoter melting by a stage-specific vaccinia virus transcription factor is independent of the presence of RNA polymerase. Cell 1991; 65:105-13. [PMID: 2013091 DOI: 10.1016/0092-8674(91)90412-r] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Fractionation of an extract prepared from HeLa cells infected with vaccinia virus resulted in the separation of factors involved in vaccinia virus intermediate transcription. Two activities, VITF-A and VITF-B, in addition to the viral RNA polymerase are necessary and sufficient to direct intermediate transcription in vitro. VITF-B confers intermediate promoter specificity to an early-specific extract prepared from virus particles. A committed complex between VITF-B and the template can sequester VITF-A and RNA polymerase into a pre-initiation complex. VITF-B is further able to melt the promoter at the start site of transcription. Open complex formation is stimulated by ATP. In contrast to prokaryotic and eukaryotic pol III transcription, promoter melting is independent of the presence of RNA polymerase.
Collapse
Affiliation(s)
- J C Vos
- European Molecular Biology Laboratory, Heidelberg, Federal Republic of Germany
| | | | | |
Collapse
|
44
|
Abstract
Bacteriophage lambda and plasmid clones containing African swine fever virus (ASFV) DNA inserts, which together covered more than 90% of the genome of a Malawi ASFV isolate (LIL 20/1), were transfected into vaccinia virus (VV)-infected cells. Expression of ASFV-encoded proteins was assayed at late times after VV infection by immunoprecipitation of [35S]methionine-labeled proteins with hyperimmune serum from ASFV-infected pigs, separation of immunoprecipitated proteins by denaturing polyacrylamide gel electrophoresis, and detection by autoradiography. Synthesis of eight additional proteins not observed in control experiments was detected. Seven VV recombinants were constructed, each containing an ASFV DNA insert from a separate bacteriophage lambda clone ranging in size from 9 to 15 kb. BSC40 cells were infected with recombinant viruses and expression of ASFV-encoded proteins assayed at early and late times postinfection. Synthesis of additional proteins, not observed in control experiments, was detected by immunoprecipitation with ASFV antiserum both early and late postinfection with two of these recombinants. In these experiments VV promoters were not included upstream of individual ASFV genes.
Collapse
Affiliation(s)
- J M Hammond
- Institute for Animal Health, Pirbright Laboratory, Surrey, United Kingdom
| | | |
Collapse
|
45
|
Fathi Z, Condit RC. Phenotypic characterization of a vaccinia virus temperature-sensitive complementation group affecting a virion component. Virology 1991; 181:273-6. [PMID: 1994577 DOI: 10.1016/0042-6822(91)90492-t] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Genetic and biochemical evidence is presented which shows that the product of the vaccinia virus gene 18R is a virion protein. Western blot analysis of virion proteins using anti-18R serum detects a 78,000-Da protein, localized in the virus core. Of five ts mutants which map to gene 18R, two mutants, ts 10 and ts 44, possess thermolabile virions. Temperature shifts performed during single-step growth of ts 44 suggest that precursors required for virion maturation accumulate during nonpermissive infections with ORF 18R mutants and that protein synthesis is required for recovery from nonpermissive condition.
Collapse
Affiliation(s)
- Z Fathi
- Department of Biochemistry, State University of New York, Buffalo 14214
| | | |
Collapse
|
46
|
Moss B, Ahn BY, Amegadzie B, Gershon PD, Keck JG. Cytoplasmic transcription system encoded by vaccinia virus. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)52298-5] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
47
|
Amegadzie BY, Holmes MH, Cole NB, Jones EV, Earl PL, Moss B. Identification, sequence, and expression of the gene encoding the second-largest subunit of the vaccinia virus DNA-dependent RNA polymerase. Virology 1991; 180:88-98. [PMID: 1824607 DOI: 10.1016/0042-6822(91)90012-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The gene, rpo 132, encoding the second-largest subunit of the vaccinia virus DNA-dependent RNA polymerase was identified and sequenced. Two complementary approaches, involving antiserum to purified vaccinia virus RNA polymerase, were used to locate the rpo 132 gene. One method involved the screening of a lambda gt11 library of vaccinia virus genome fragments and the other was based on the immunoprecipitation and polyacrylamide gel electrophoresis of the in vitro translation products of mRNA that hybridized to immobilized vaccinia virus DNA. The deduced open reading frame of the rpo 132 gene predicted a polypeptide of 1164 amino acid residues with sequence similarities to the second-largest RNA polymerase subunits of eubacteria, archaebacteria, and eukaryotes as well as to other poxviruses. Transcriptional analyses indicated that rpo 132 has both early and late RNA start sites and is expressed throughout infection.
Collapse
MESH Headings
- Amino Acid Sequence
- Bacteriophage lambda
- Base Sequence
- Blotting, Northern
- Blotting, Southern
- Cloning, Molecular
- DNA, Viral
- DNA-Directed RNA Polymerases/biosynthesis
- DNA-Directed RNA Polymerases/genetics
- Electrophoresis, Polyacrylamide Gel
- Gene Expression/genetics
- Gene Library
- Genes, Viral
- Molecular Sequence Data
- Peptide Mapping
- Plasmids
- Poxviridae/genetics
- Precipitin Tests
- RNA, Messenger
- RNA, Viral
- Sequence Homology, Nucleic Acid
- Transcription, Genetic/genetics
- Vaccinia virus/enzymology
- Vaccinia virus/genetics
Collapse
Affiliation(s)
- B Y Amegadzie
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | | | | | | | | | | |
Collapse
|
48
|
Broyles SS, Pennington MJ. Vaccinia virus gene encoding a 30-kilodalton subunit of the viral DNA-dependent RNA polymerase. J Virol 1990; 64:5376-82. [PMID: 2214020 PMCID: PMC248587 DOI: 10.1128/jvi.64.11.5376-5382.1990] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Antibody was raised against purified vaccinia virus RNA polymerase and used to screen a recombinant vaccinia virus-lambda gt11 library. The DNA from several immunopositive clones was shown by Southern hybridization to originate from the vaccinia virus HindIII E fragment. The nucleotide sequence of the RNA polymerase subunit gene predicts a polypeptide 287 amino acids in length and 30,000 daltons in mass. An early transcript with a 5' terminus just upstream of the putative initiation codon was identified by S1 nuclease protection and primer extension analyses, demonstrating that this RNA polymerase subunit is expressed as an early viral gene product. The RNA polymerase subunit was synthesized by a bacterial expression vector to demonstrate that it corresponds to the previously described 37,000-dalton RNA polymerase subunit.
Collapse
Affiliation(s)
- S S Broyles
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907-6799
| | | |
Collapse
|
49
|
Abstract
A novel bidirectional promoter element of fowlpox virus (FPV) was characterized by transcription analysis, transient expression assays, and recombinant virus construction. This promoter element contained an early/late and a late function in opposite orientation, all within 42 bp of the DNA sequence. The 42-bp sequence was sufficient to express two reporter genes simultaneously in a temporally regulated manner. Both early and late mRNA from the early/late promoter originated at the same TAAAT motif and lacked a long 5'poly(A) leader sequence. Late mRNA, initiated from a TAAAT motif of the oppositely oriented late promoter strand, had a leader sequence of approximately 26 bases. Sequence alignment of two strands of the bidirectional element showed that 28 of 42 bases matched. Because of its small and defined size as well as unique structure, this bidirectional promoter should prove to be an important tool in defining the sequences required for the temporal regulation of poxvirus genes.
Collapse
Affiliation(s)
- S Kumar
- Commonwealth Scientific Industrial Research Organisation, Australia Animal Health Laboratory, Geelong, Victoria
| | | |
Collapse
|
50
|
Quick SD, Broyles SS. Vaccinia virus gene D7R encodes a 20,000-dalton subunit of the viral DNA-dependent RNA polymerase. Virology 1990; 178:603-5. [PMID: 2219712 DOI: 10.1016/0042-6822(90)90362-u] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The polypeptide encoded by the vaccinia virus open reading frame D7R was synthesized in bacteria. Immunization of rabbits with the polypeptide resulted in antibodies that specifically recognized a virion polypeptide of 20,000 daltons. The immunoreactivity with the 20,000-dalton polypeptide was found to coincide with the virion-associated DNA-dependent RNA polymerase through DEAE-cellulose chromatography and glycerol gradient sedimentation. These results argue that the product of the vaccinia open reading frame D7R is a subunit of the viral RNA polymerase.
Collapse
Affiliation(s)
- S D Quick
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
| | | |
Collapse
|