1
|
Lu J, Xing H, Wang C, Tang M, Wu C, Ye F, Yin L, Yang Y, Tan W, Shen L. Mpox (formerly monkeypox): pathogenesis, prevention, and treatment. Signal Transduct Target Ther 2023; 8:458. [PMID: 38148355 PMCID: PMC10751291 DOI: 10.1038/s41392-023-01675-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/14/2023] [Accepted: 09/21/2023] [Indexed: 12/28/2023] Open
Abstract
In 2022, a global outbreak of Mpox (formerly monkeypox) occurred in various countries across Europe and America and rapidly spread to more than 100 countries and regions. The World Health Organization declared the outbreak to be a public health emergency of international concern due to the rapid spread of the Mpox virus. Consequently, nations intensified their efforts to explore treatment strategies aimed at combating the infection and its dissemination. Nevertheless, the available therapeutic options for Mpox virus infection remain limited. So far, only a few numbers of antiviral compounds have been approved by regulatory authorities. Given the high mutability of the Mpox virus, certain mutant strains have shown resistance to existing pharmaceutical interventions. This highlights the urgent need to develop novel antiviral drugs that can combat both drug resistance and the potential threat of bioterrorism. Currently, there is a lack of comprehensive literature on the pathophysiology and treatment of Mpox. To address this issue, we conducted a review covering the physiological and pathological processes of Mpox infection, summarizing the latest progress of anti-Mpox drugs. Our analysis encompasses approved drugs currently employed in clinical settings, as well as newly identified small-molecule compounds and antibody drugs displaying potential antiviral efficacy against Mpox. Furthermore, we have gained valuable insights from the process of Mpox drug development, including strategies for repurposing drugs, the discovery of drug targets driven by artificial intelligence, and preclinical drug development. The purpose of this review is to provide readers with a comprehensive overview of the current knowledge on Mpox.
Collapse
Affiliation(s)
- Junjie Lu
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei Province, Xiangyang, 441021, China
| | - Hui Xing
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei Province, Xiangyang, 441021, China
| | - Chunhua Wang
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei Province, Xiangyang, 441021, China
| | - Mengjun Tang
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei Province, Xiangyang, 441021, China
| | - Changcheng Wu
- NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China
| | - Fan Ye
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei Province, Xiangyang, 441021, China
| | - Lijuan Yin
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Yang Yang
- Shenzhen Key Laboratory of Pathogen and Immunity, National Clinical Research Center for infectious disease, State Key Discipline of Infectious Disease, Shenzhen Third People's Hospital, Second Hospital Affiliated to Southern University of Science and Technology, Shenzhen, 518112, China.
| | - Wenjie Tan
- NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, China.
| | - Liang Shen
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Hubei Province, Xiangyang, 441021, China.
| |
Collapse
|
2
|
Time-Course Transcriptome Profiling of a Poxvirus Using Long-Read Full-Length Assay. Pathogens 2021; 10:pathogens10080919. [PMID: 34451383 PMCID: PMC8398953 DOI: 10.3390/pathogens10080919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/29/2021] [Accepted: 07/12/2021] [Indexed: 11/16/2022] Open
Abstract
Viral transcriptomes that are determined using first- and second-generation sequencing techniques are incomplete. Due to the short read length, these methods are inefficient or fail to distinguish between transcript isoforms, polycistronic RNAs, and transcriptional overlaps and readthroughs. Additionally, these approaches are insensitive for the identification of splice and transcriptional start sites (TSSs) and, in most cases, transcriptional end sites (TESs), especially in transcript isoforms with varying transcript ends, and in multi-spliced transcripts. Long-read sequencing is able to read full-length nucleic acids and can therefore be used to assemble complete transcriptome atlases. Although vaccinia virus (VACV) does not produce spliced RNAs, its transcriptome has a high diversity of TSSs and TESs, and a high degree of polycistronism that leads to enormous complexity. We applied single-molecule, real-time, and nanopore-based sequencing methods to investigate the time-lapse transcriptome patterns of VACV gene expression.
Collapse
|
3
|
Long-read assays shed new light on the transcriptome complexity of a viral pathogen. Sci Rep 2020; 10:13822. [PMID: 32796917 PMCID: PMC7427789 DOI: 10.1038/s41598-020-70794-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 08/03/2020] [Indexed: 12/21/2022] Open
Abstract
Characterization of global transcriptomes using conventional short-read sequencing is challenging due to the insensitivity of these platforms to transcripts isoforms, multigenic RNA molecules, and transcriptional overlaps. Long-read sequencing (LRS) can overcome these limitations by reading full-length transcripts. Employment of these technologies has led to the redefinition of transcriptional complexities in reported organisms. In this study, we applied LRS platforms from Pacific Biosciences and Oxford Nanopore Technologies to profile the vaccinia virus (VACV) transcriptome. We performed cDNA and direct RNA sequencing analyses and revealed an extremely complex transcriptional landscape of this virus. In particular, VACV genes produce large numbers of transcript isoforms that vary in their start and termination sites. A significant fraction of VACV transcripts start or end within coding regions of neighbouring genes. This study provides new insights into the transcriptomic profile of this viral pathogen.
Collapse
|
4
|
Vopálenský V, Sýkora M, Mašek T, Pospíšek M. Messenger RNAs of Yeast Virus-Like Elements Contain Non-templated 5' Poly(A) Leaders, and Their Expression Is Independent of eIF4E and Pab1. Front Microbiol 2019; 10:2366. [PMID: 31736885 PMCID: PMC6831550 DOI: 10.3389/fmicb.2019.02366] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 09/30/2019] [Indexed: 02/01/2023] Open
Abstract
We employed virus-like elements (VLEs) pGKL1,2 from Kluyveromyces lactis as a model to investigate the previously neglected transcriptome of the broader group of yeast cytoplasmic linear dsDNA VLEs. We performed 5′ and 3′ RACE analyses of all pGKL1,2 mRNAs and found them not 3′ polyadenylated and containing frequently uncapped 5′ poly(A) leaders that are not complementary to VLE genomic DNA. The degree of 5′ capping and/or 5′ mRNA polyadenylation is specific to each gene and is controlled by the corresponding promoter region. The expression of pGKL1,2 transcripts is independent of eIF4E and Pab1 and is enhanced in lsm1Δ and pab1Δ strains. We suggest a model of primitive pGKL1,2 gene expression regulation in which the degree of 5′ mRNA capping and 5′ non-template polyadenylation, together with the presence of negative regulators such as Pab1 and Lsm1, play important roles. Our data also support a hypothesis of a close relationship between yeast linear VLEs and poxviruses.
Collapse
Affiliation(s)
- Václav Vopálenský
- Laboratory of RNA Biochemistry, Department of Genetics and Microbiology, Faculty of Science, Charles University, Prague, Czechia
| | - Michal Sýkora
- Laboratory of RNA Biochemistry, Department of Genetics and Microbiology, Faculty of Science, Charles University, Prague, Czechia
| | - Tomáš Mašek
- Laboratory of RNA Biochemistry, Department of Genetics and Microbiology, Faculty of Science, Charles University, Prague, Czechia
| | - Martin Pospíšek
- Laboratory of RNA Biochemistry, Department of Genetics and Microbiology, Faculty of Science, Charles University, Prague, Czechia
| |
Collapse
|
5
|
Moussatche N, Condit RC. Fine structure of the vaccinia virion determined by controlled degradation and immunolocalization. Virology 2014; 475:204-18. [PMID: 25486587 DOI: 10.1016/j.virol.2014.11.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 11/18/2014] [Indexed: 10/24/2022]
Abstract
The vaccinia virion is a membraned, slightly flattened, barrel-shaped particle, with a complex internal structure featuring a biconcave core flanked by lateral bodies. Although the architecture of the purified mature virion has been intensely characterized by electron microscopy, the distribution of the proteins within the virion has been examined primarily using biochemical procedures. Thus, it has been shown that non-ionic and ionic detergents combined or not with a sulfhydryl reagent can be used to disrupt virions and, to a limited degree, separate the constituent proteins in different fractions. Applying a controlled degradation technique to virions adsorbed on EM grids, we were able to immuno-localize viral proteins within the virion particle. Our results show after NP40 and DTT treatment, membrane proteins are removed from the virion surface revealing proteins that are associated with the lateral bodies and the outer layer of the core wall. Combined treatment using high salt and high DTT removed lateral body proteins and exposed proteins of the internal core wall. Cores treated with proteases could be disrupted and the internal components were exposed. Cts8, a mutant in the A3 protein, produces aberrant virus that, when treated with NP-40 and DTT, releases to the exterior the virus DNA associated with other internal core proteins. With these results, we are able to propose a model for the structure the vaccinia virion.
Collapse
Affiliation(s)
- Nissin Moussatche
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32610, USA.
| | - Richard C Condit
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32610, USA
| |
Collapse
|
6
|
Matson J, Chou W, Ngo T, Gershon PD. Static and dynamic protein phosphorylation in the Vaccinia virion. Virology 2014; 452-453:310-23. [PMID: 24606709 DOI: 10.1016/j.virol.2014.01.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 12/02/2013] [Accepted: 01/17/2014] [Indexed: 11/19/2022]
Abstract
To the best of our knowledge, two phosphorylation sites have been reported previously, among 11 known Vaccinia virus phosphoproteins. Here, via phosphopeptide mass spectrometry, up to 189 phosphorylation sites were identified among 48 proteins in preparations of purified Vaccinia mature virus (MV). 8.5% of phospho-residues were pTyr. Viral phosphoproteins were found in diverse functional classes, including structural proteins, membrane proteins and RNA polymerase subunits. Among the nine identified membrane phosphoproteins, the sites in just one, namely A14L, were deduced to be internal with respect to the accompanying membrane. Examination of sites in known substrates of the Vaccinia-encoded protein kinase VPK2, indicated VPK2 to be a proline-dependent kinase. The MV phosphoproteome was enriched in potential substrates of cellular kinases belonging to the CDK2/CDK3, CK2, and p38 groups. Quantitative mass spectrometry identified several sites that became phosphorylated during intravirion kinase activation in vitro, each showing one of two distinct pH-dependency profiles.
Collapse
Affiliation(s)
- J Matson
- University of North Carolina, Chapel Hill, NC, United States
| | - W Chou
- Department of Molecular Biology and Biochemistry, UC-Irvine, Irvine, CA 92697, United States
| | - T Ngo
- Department of Molecular Biology and Biochemistry, UC-Irvine, Irvine, CA 92697, United States
| | - P D Gershon
- Department of Molecular Biology and Biochemistry, UC-Irvine, Irvine, CA 92697, United States.
| |
Collapse
|
7
|
RNAi Screening Reveals Proteasome- and Cullin3-Dependent Stages in Vaccinia Virus Infection. Cell Rep 2012; 2:1036-47. [DOI: 10.1016/j.celrep.2012.09.003] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 08/30/2012] [Accepted: 09/07/2012] [Indexed: 11/19/2022] Open
|
8
|
Identification of a pyridopyrimidinone inhibitor of orthopoxviruses from a diversity-oriented synthesis library. J Virol 2011; 86:2632-40. [PMID: 22205744 DOI: 10.1128/jvi.05416-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Orthopoxviruses include the prototypical vaccinia virus, the emerging infectious agent monkeypox virus, and the potential biothreat variola virus (the causative agent of smallpox). There is currently no FDA-approved drug for humans infected with orthopoxviruses. We screened a diversity-oriented synthesis library for new scaffolds with activity against vaccinia virus. This screen identified a nonnucleoside analog that blocked postreplicative intermediate and late gene expression. Viral genome replication was unaffected, and inhibition could be elicited late in infection and persisted upon drug removal. Sequencing of drug-resistant viruses revealed mutations predicted to be on the periphery of the highly conserved viral RNA polymerase large subunit. Consistent with this, the compound had broad-spectrum activity against orthopoxviruses in vitro. These findings indicate that novel chemical synthesis approaches are a potential source for new infectious disease therapeutics and identify a potentially promising candidate for development to treat orthopoxvirus-infected individuals.
Collapse
|
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
|
Vermeer PD, McHugh J, Rokhlina T, Vermeer DW, Zabner J, Welsh MJ. Vaccinia virus entry, exit, and interaction with differentiated human airway epithelia. J Virol 2007; 81:9891-9. [PMID: 17581984 PMCID: PMC2045410 DOI: 10.1128/jvi.00601-07] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Variola virus, the causative agent of smallpox, enters and exits the host via the respiratory route. To better understand the pathogenesis of poxvirus infection and its interaction with respiratory epithelia, we used vaccinia virus and examined its interaction with primary cultures of well-differentiated human airway epithelia. We found that vaccinia virus preferentially infected the epithelia through the basolateral membrane and released viral progeny across the apical membrane. Despite infection and virus production, epithelia retained tight junctions, transepithelial electrical conductance, and a steep transepithelial concentration gradient of virus, indicating integrity of the epithelial barrier. In fact, during the first four days of infection, epithelial height and cell number increased. These morphological changes and maintenance of epithelial integrity required vaccinia virus growth factor, which was released basolaterally, where it activated epidermal growth factor 1 receptors. These data suggest a complex interaction between the virus and differentiated airway epithelia; the virus preferentially enters the cells basolaterally, exits apically, and maintains epithelial integrity by stimulating growth factor receptors.
Collapse
Affiliation(s)
- Paola D Vermeer
- Howard Hughes Medical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 500 EMRB, Iowa City, IA 52242, USA
| | | | | | | | | | | |
Collapse
|
11
|
Abstract
Poxviruses, a family of large DNA viruses, are unique among DNA viruses, because they carry out DNA replication in the cytoplasm rather than the nucleus. This process does not occur randomly, but instead, these viruses create cytoplasmic 'mini-nuclei', distinct sites that are surrounded by membranes derived from the rough endoplasmic reticulum (ER) that support viral replication. This review summarizes how distinct steps preceding cytoplasmic DNA replication, as well as replication itself, operate in the host cell. The collective data point to an important role for both the rough ER and the microtubules and indicate that these cellular structures help to co-ordinate the virus life cycle to ensure that individual steps occur at the right time and place. In a broader sense, they emphasize how viruses have evolved sophisticated ways to use host cells to optimize their life cycles to ensure efficient production of infectious progeny.
Collapse
Affiliation(s)
- Birgit Schramm
- European Molecular Biology Laboratory, Cell Biology and Biophysics Programme, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | | |
Collapse
|
12
|
Cyrklaff M, Risco C, Fernández JJ, Jiménez MV, Estéban M, Baumeister W, Carrascosa JL. Cryo-electron tomography of vaccinia virus. Proc Natl Acad Sci U S A 2005; 102:2772-7. [PMID: 15699328 PMCID: PMC549483 DOI: 10.1073/pnas.0409825102] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The combination of cryo-microscopy and electron tomographic reconstruction has allowed us to determine the structure of one of the more complex viruses, intracellular mature vaccinia virus, at a resolution of 4-6 nm. The tomographic reconstruction allows us to dissect the different structural components of the viral particle, avoiding projection artifacts derived from previous microscopic observations. A surface-rendering representation revealed brick-shaped viral particles with slightly rounded edges and dimensions of approximately 360 x 270 x 250 nm. The outer layer was consistent with a lipid membrane (5-6 nm thick), below which usually two lateral bodies were found, built up by a heterogeneous material without apparent ordering or repetitive features. The internal core presented an inner cavity with electron dense coils of presumptive DNA-protein complexes, together with areas of very low density. The core was surrounded by two layers comprising an overall thickness of approximately 18-19 nm; the inner layer was consistent with a lipid membrane. The outer layer was discontinuous, formed by a periodic palisade built by the side interaction of T-shaped protein spikes that were anchored in the lower membrane and were arranged into small hexagonal crystallites. It was possible to detect a few pore-like structures that communicated the inner side of the core with the region outside the layer built by the T-shaped spike palisade.
Collapse
Affiliation(s)
- Marek Cyrklaff
- Max Planck Institute of Biochemistry, Am Klopferspitz 18a, D-82152 Martinsried, Germany
| | | | | | | | | | | | | |
Collapse
|
13
|
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
|
14
|
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
|
15
|
Abstract
Vaccinia virus (VV), the virus smallpox vaccine, replicates in the cytoplasm of infected cells. The intracellular movement of this large virus would be inefficient without specific transport mechanisms; therefore, VV uses microtubules for movement during both entry and egress. In addition, the dissemination of virus from infected cells to adjacent cells is promoted by the polymerization of actin beneath cell surface virions to drive virus particles away from the cell. Last, the roles of different VV particles in virus movement within and between hosts are discussed.
Collapse
Affiliation(s)
- Geoffrey L Smith
- Department of Virology, The Wright-Fleming Institute, Faculty of Medicine, Imperial College London, St. Mary's Campus, Norfolk Place, London W2 1PG, United Kingdom.
| | | | | |
Collapse
|
16
|
Malkin AJ, McPherson A, Gershon PD. Structure of intracellular mature vaccinia virus visualized by in situ atomic force microscopy. J Virol 2003; 77:6332-40. [PMID: 12743290 PMCID: PMC155008 DOI: 10.1128/jvi.77.11.6332-6340.2003] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2002] [Accepted: 03/04/2003] [Indexed: 11/20/2022] Open
Abstract
Vaccinia virus, the basis of the smallpox vaccine, is one of the largest viruses to replicate in humans. We have used in situ atomic force microscopy (AFM) to directly visualize fully hydrated, intact intracellular mature vaccinia virus (IMV) virions and chemical and enzymatic treatment products thereof. The latter included virion cores, core-enveloping coats, and core substructures. The isolated coats appeared to be composed of a highly cross-linked protein array. AFM imaging of core substructures indicated association of the linear viral DNA genome with a segmented protein sheath forming an extended approximately 16-nm-diameter filament with helical surface topography; enclosure of this filament within a 30- to 40-nm-diameter tubule which also shows helical topography; and enclosure of the folded, condensed 30- to 40-nm-diameter tubule within the core by a wall covered with peg-like projections. Proteins observed attached to the 30- to 40-nm-diameter tubules may mediate folding and/or compaction of the tubules and/or represent vestiges of the core wall and/or pegs. An accessory "satellite domain" was observed protruding from the intact core. This corresponded in size to isolated 70- to 100-nm-diameter particles that were imaged independently and might represent detached accessory domains. AFM imaging of intact virions indicated that IMV underwent a reversible shrinkage upon dehydration (as much as 2.2- to 2.5-fold in the height dimension), accompanied by topological and topographical changes, including protrusion of the satellite domain. As shown here, the chemical and enzymatic dissection of large, asymmetrical virus particles in combination with in situ AFM provides an informative complement to other structure determination techniques.
Collapse
Affiliation(s)
- A J Malkin
- BioSecurity and NanoSciences Laboratory, Department of Chemistry and Materials Science, Lawrence Livermore National Laboratory, California 94551, USA.
| | | | | |
Collapse
|
17
|
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
|
18
|
Mallardo M, Leithe E, Schleich S, Roos N, Doglio L, Krijnse Locker J. Relationship between vaccinia virus intracellular cores, early mRNAs, and DNA replication sites. J Virol 2002; 76:5167-83. [PMID: 11967332 PMCID: PMC136133 DOI: 10.1128/jvi.76.10.5167-5183.2002] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Virus assembly, a late event in the life cycle of vaccinia virus (VV), is preceded by a number of steps that all occur in the cytoplasm of the infected host cell: virion entry, delivery of the viral core into the cytoplasm, and transcription from these cores of early mRNAs, followed by the process of DNA replication. In the present study the quantitative and structural relationships between these distinct steps of VV morphogenesis were investigated. We show that viral RNA and DNA synthesis increases linearly with increasing amounts of incoming cores. Moreover, at multiplicities of infection that result in 10 to 40 cores per cell, an approximately 1:1 ratio between cores and sites of DNA replication exists, suggesting that each core is infectious. We have shown previously that VV early mRNAs collect in distinct granular structures that recruit components of the host cell translation machinery. Strikingly, these structures appeared to form some distance away from intracellular cores (M. Mallardo, S. Schleich, and J. Krijnse Locker, Mol. Biol. Cell 12:3875-3891, 2001). In the present study the intracellular locations of the sites of early mRNA accumulation and those of the subsequent process of DNA replication were compared. We show that these are distinct structures that have different intracellular locations. Finally, we study the fate of the parental DNA after core uncoating. By electron microscopy, cores were found close to membranes of the endoplasmic reticulum (ER) and the parental DNA, once it had left the core, appeared to associate preferentially with the cytosolic side of those membranes. Since we have previously shown that the process of DNA replication occurs in an ER-enclosed cytosolic "subcompartment" (N. Tolonen, L. Doglio, S. Schleich, and J. Krijnse Locker, Mol. Biol. Cell 12:2031-2046, 2001), the present data suggest that the parental DNA is released into the cytosol and associates with the same membranes where DNA replication is subsequently initiated. The combined data are discussed with respect to the cytosolic organization of VV morphogenesis.
Collapse
Affiliation(s)
- Massimo Mallardo
- Cell Biology and Biophysics Programme, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | | | | | | | | | | |
Collapse
|
19
|
Mallardo M, Schleich S, Krijnse Locker J. Microtubule-dependent organization of vaccinia virus core-derived early mRNAs into distinct cytoplasmic structures. Mol Biol Cell 2001; 12:3875-91. [PMID: 11739787 PMCID: PMC60762 DOI: 10.1091/mbc.12.12.3875] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Vaccinia virus (vv) early transcription can be reconstituted in vitro from purified virions; in this assay mRNAs are made inside the viral core and subsequently extruded. Although the in vitro process has been extensively characterized, relatively little is known about vv early transcription in vivo. In the present study the fate of vv early mRNAs in infected HeLa cells was followed by BrUTP transfection and confocal and electron microscopy. The extruded vv early mRNAs were found to be organized into unique granular cytoplasmic structures that reached a size up to 1 microm. By EM these structures appeared as amorphous electron-dense cytoplasmic aggregates that were surrounded by ribosomes. Confocal images showed that the RNA structures were located some distance away from intracellular cores and that both structures appeared to be aligned on microtubules (MTs), implying that MT tracks connected mRNAs and cores. Accordingly, intact MTs were found to be required for the typical punctate organization of viral mRNAs. Biochemical evidence supported the notion that vv mRNAs were MT associated and that MT depletion severely affected viral (but not cellular) mRNA synthesis and stability. By confocal microscopy the viral mRNA structures appeared to be surrounded by molecules of the translation machinery, showing that they were active in protein synthesis. Finally, our data suggest a role for a MT and RNA-binding viral protein of 25 kDa (gene L4R), in mRNA targeting away from intracellular cores to their sites of cytoplasmic accumulation.
Collapse
Affiliation(s)
- M Mallardo
- EMBL, Cell Biology and Biophysics Programme, 69117 Heidelberg, Germany.
| | | | | |
Collapse
|
20
|
Locker JK, Griffiths G. An unconventional role for cytoplasmic disulfide bonds in vaccinia virus proteins. J Cell Biol 1999; 144:267-79. [PMID: 9922453 PMCID: PMC2132897 DOI: 10.1083/jcb.144.2.267] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/1998] [Revised: 12/02/1998] [Indexed: 01/20/2023] Open
Abstract
Previous data have shown that reducing agents disrupt the structure of vaccinia virus (vv). Here, we have analyzed the disulfide bonding of vv proteins in detail. In vv-infected cells cytoplasmically synthesized vv core proteins became disulfide bonded in the newly assembled intracellular mature viruses (IMVs). vv membrane proteins also assembled disulfide bonds, but independent of IMV formation and to a large extent on their cytoplasmic domains. If disulfide bonding was prevented, virus assembly was only partially impaired as shown by electron microscopy as well as a biochemical assay of IMV formation. Under these conditions, however, the membranes around the isolated particles appeared less stable and detached from the underlying core. During the viral infection process the membrane proteins remained disulfide bonded, whereas the core proteins were reduced, concomitant with delivery of the cores into the cytoplasm. Our data show that vv has evolved an unique system for the assembly of cytoplasmic disulfide bonds that are localized both on the exterior and interior parts of the IMV.
Collapse
Affiliation(s)
- J K Locker
- European Molecular Biology Laboratory, Cell Biology Programme, 69117 Heidelberg, Germany.
| | | |
Collapse
|
21
|
Gross CH, Shuman S. Vaccinia virions lacking the RNA helicase nucleoside triphosphate phosphohydrolase II are defective in early transcription. J Virol 1996; 70:8549-57. [PMID: 8970979 PMCID: PMC190947 DOI: 10.1128/jvi.70.12.8549-8557.1996] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Temperature-sensitive mutations (ts10, ts18, and ts39) of the vaccinia virus RNA helicase nucleoside triphosphate phosphohydrolase II (NPH-II) result in the production of noninfectious progeny virions at the restrictive temperature. The noninfectious mutant particles contain the wild-type complement of virion core and envelope polypeptides, as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The results of Western blot (immunoblot) analysis indicate that these particles lack NPH-II, whereas other enzymatic components of the virus core are present. These components include the following: DNA-dependent RNA polymerase subunits rpo147, rpo132, rpo94, rpo35, rpo30, rpo22, and rpo18; early transcription initiation factor subunits A8 and D6; mRNA capping enzyme subunits D1 and D12; RNA cap 2'-O-methyltransferase; A18 DNA helicase; DNA-dependent ATPase NPH-I; and DNA topoisomerase. Although RNA polymerase is encapsidated by the mutant viruses, mRNA synthesis in vitro by permeabilized mutant virions is only 5 to 20% that of the wild-type virus, as judged by nucleoside monophosphate incorporation into acid-insoluble material. Moreover, the transcripts synthesized by the mutant particles are longer than normal and remain virion associated. Transcription initiation by mutant virions occurs accurately at an endogenous genomic promoter, albeit at reduced levels (1 to 7%) compared with that of wild-type virions. In contrast, extracts of the mutant virions catalyze the wild-type level of transcription from an exogenous template containing an early promoter. We conclude that NPH-II is required for early mRNA synthesis uniquely in the context of the virus particle. Possible roles in transcription termination and RNA transport are discussed.
Collapse
Affiliation(s)
- C H Gross
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10021, USA
| | | |
Collapse
|
22
|
Deng L, Shuman S. An ATPase component of the transcription elongation complex is required for factor-dependent transcription termination by vaccinia RNA polymerase. J Biol Chem 1996; 271:29386-92. [PMID: 8910603 DOI: 10.1074/jbc.271.46.29386] [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: 02/03/2023] Open
Abstract
Vaccinia virus RNA polymerase terminates transcription in response to a specific signal UUUUUNU in the nascent transcript. Transduction of this signal to the elongating polymerase requires a virus-encoded termination factor, VTF. The existence of a second termination factor was suggested by the finding that transient exposure of purified elongation complexes to heparin rendered them refractory to VTF-induced termination. Loss of termination competence correlated with the removal of several polypeptide components of the elongation complex. We present the identification of factor X, an activity that restored VTF responsiveness to heparin-stripped ternary complexes. We propose that factor X, which has an associated DNA-dependent ATPase activity, mediates the requirement for ATP hydrolysis during transcription termination.
Collapse
Affiliation(s)
- L Deng
- Molecular Biology Program, Sloan-Kettering Institute, New York, New York 10021, USA.
| | | |
Collapse
|
23
|
Abstract
When synthesis of the 25-kDa vaccinia virus core protein VP8 is repressed, mature virus particles of normal appearance are produced to approximately 80% of wild-type levels but these particles are over 100-fold less infectious than wild-type particles (D. Wilcock and G. L. Smith, Virology 202:294-304, 1994). Here we show that virions which lack VP8 can bind to and enter cells but the levels of steady-state RNA are greatly reduced in comparison with those for wild-type infections. In vitro assays using permeabilized virions demonstrated that VP8-deficient virions had drastically reduced rates of transcription (RNA synthesis was decreased by 80 to 96%) and that the extrusion of RNA transcripts from these virions was also decreased. Low concentrations of sodium deoxycholate extracted proteins more efficiently from VP8-deficient virions than from wild-type virions. The increased fragility of VP8-deficient virions and their slower RNA extrusion rates suggest that VP8 may be required for the correct formation of the core. Virions which lack VP8 were shown to contain a full complement of transcription enzymes, and soluble extracts from these virions were active in transcription assays using either single-stranded M13 DNA or exogenous plasmid template containing a vaccinia virus early promoter. Thus, the defect in transcription is due not to a lack of specific transcriptional enzymes within virions but rather to the inability of these enzymes to efficiently transcribe the DNA genome packaged within VP8-deficient virions. These results suggest that VP8 is required for the correct packaging of the viral DNA genome and/or for the efficient transcription of packaged virion DNA, which has a higher degree of structural complexity than plasmid templates. Possible roles for VP8 in these processes are discussed.
Collapse
Affiliation(s)
- D Wilcock
- Sir William Dunn School of Pathology, University of Oxford, United Kingdom
| | | |
Collapse
|
24
|
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
|
25
|
Zhang Y, Ahn BY, Moss B. Targeting of a multicomponent transcription apparatus into assembling vaccinia virus particles requires RAP94, an RNA polymerase-associated protein. J Virol 1994; 68:1360-70. [PMID: 8107201 PMCID: PMC236590 DOI: 10.1128/jvi.68.3.1360-1370.1994] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
When expression of the vaccinia virus gene encoding RAP94 (a protein that is associated with the viral multisubunit RNA polymerase and confers transcriptional specificity for early promoters) was repressed, the infectious virus yield was reduced by more than 99%. Nevertheless, intermediate- and late-stage viral gene expression and formation of ultrastructurally mature, membrane-enveloped virions occurred under the nonpermissive conditions. The RAP94-deficient particles contained the viral genome, structural proteins, early transcription factor, and certain enzymes but, unlike normal virions, had low or undetectable amounts of the viral RNA polymerase, capping enzyme/termination factor, poly(A) polymerase, DNA-dependent ATPase, RNA helicase, and topoisomerase. The presence of these viral enzymes in the cytoplasm indicated that RAP94 is required for targeting a complex of functionally related proteins involved in the biosynthesis of mRNA.
Collapse
Affiliation(s)
- Y Zhang
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892
| | | | | |
Collapse
|
26
|
Abstract
This chapter focuses on the contributions that studies with viruses have made to current concepts in cell biology. Among the important advantages that viruses provide in such studies is their structural and genetic simplicity. The chapter describes the methods for growth, assay, and purification of viruses and infection of cells by several viruses that have been widely utilized for studies of cellular processes. Most investigations of virus replication at the cellular level are carried out using animal cells in culture. For the events in individual cells to occur with a high level of synchrony, single cycle growth conditions are used. Cells are infected using a high multiplicity of infectious virus particles in a low volume of medium to enhance the efficiency of virus adsorption to cell surfaces. After the adsorption period, the residual inoculum is removed and replaced with an appropriate culture medium. During further incubation, each individual cell in the culture is at a similar temporal stage in the viral replication process. Therefore, experimental procedures carried out on the entire culture reflect the replicative events occurring within an individual cell. The length of a single cycle of virus growth can range from a few hours to several days, depending on the virus type.
Collapse
Affiliation(s)
- R W Compans
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322
| | | |
Collapse
|
27
|
MESH Headings
- Animals
- Base Sequence
- Cell Line
- DNA Replication
- DNA, Recombinant/metabolism
- Gene Products, env/biosynthesis
- Gene Products, env/genetics
- Gene Products, env/isolation & purification
- Genetic Vectors
- HIV Envelope Protein gp120/biosynthesis
- HIV Envelope Protein gp120/genetics
- HIV Envelope Protein gp120/isolation & purification
- HIV Envelope Protein gp160
- HIV-1/genetics
- Humans
- Plasmids
- Promoter Regions, Genetic
- Protein Precursors/biosynthesis
- Protein Precursors/genetics
- Protein Precursors/isolation & purification
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Recombination, Genetic
- Restriction Mapping
- Terminator Regions, Genetic
- Transcription, Genetic
- Transfection/methods
- Vaccinia virus/genetics
- Vaccinia virus/growth & development
Collapse
Affiliation(s)
- G P Mazzara
- Therion Biologics Corporation, Cambridge, Massachusetts 02142
| | | | | |
Collapse
|
28
|
Shuman S. Vaccinia virus RNA helicase: an essential enzyme related to the DE-H family of RNA-dependent NTPases. Proc Natl Acad Sci U S A 1992; 89:10935-9. [PMID: 1332061 PMCID: PMC50457 DOI: 10.1073/pnas.89.22.10935] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Three distinct nucleic acid-dependent ATPases are packaged within infectious vaccinia virus particles; one of these enzymes (nucleoside triphosphate phosphohydrolase II or NPH-II) is activated by single-stranded RNA. Purified NPH-II is now shown to be an NTP-dependent RNA helicase. RNA unwinding requires a divalent cation and any one of the eight common ribo- or deoxyribonucleoside triphosphates. The enzyme acts catalytically to displace an estimated 10-fold molar excess of duplex RNA under in vitro reaction conditions. NPH-II binds to single-stranded RNA. Turnover of the bound enzyme is stimulated by and coupled to hydrolysis of NTP. Photocrosslinking of radiolabeled RNA to NPH-II results in label transfer to a single 73-kDa polypeptide. The sedimentation properties of the helicase are consistent with NPH-II being a monomer of this protein. Immunoblotting experiments identify NPH-II as the product of the vaccinia virus I8 gene. The I8-encoded protein displays extensive sequence similarity to members of the DE-H family of RNA-dependent NTPases. Mutations in the NPH-II gene [Fathi, Z. & Condit, R.C. (1991) Virology 181, 258-272] define the vaccinia helicase as essential for virus replication in vivo. Encapsidation of NPH-II in the virus particle suggests a role for the enzyme in synthesis of early messenger RNAs by the virion-associated transcription machinery.
Collapse
Affiliation(s)
- S Shuman
- Program in Molecular Biology, Sloan-Kettering Institute, New York, NY 10021
| |
Collapse
|
29
|
Kumagai H, Kon R, Hoshino T, Aramaki T, Nishikawa M, Hirose S, Igarashi K. Purification and properties of a decapping enzyme from rat liver cytosol. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1119:45-51. [PMID: 1540634 DOI: 10.1016/0167-4838(92)90232-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A decapping enzyme has been purified about 2400-fold from rat liver cytosol. The decapping enzyme was shown to be fairly homogeneous by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The enzyme had an apparent molecular weight of 110,000 and consisted of two equal subunits. The enzyme hydrolyzed m7Guo5'PPP5'Ado to m7GMP and ADP. Analysis of the products produced from radioactively capped oligonucleotides and intact mRNA having 3H-cap suggests that the enzyme can hydrolyze capped mono- to pentanucleotides (m7Guo5'PPP5'N (where N = 1-5 nucleotides)) but not intact mRNA. The existence of methyl group at the N7 position of guanosine moiety of cap structure was necessary for the action of the decapping enzyme. This was confirmed by the comparison of the rates of hydrolysis of m7Guo5'PPP5'Ado by the enzyme in the presence of various nucleotides. The activity of enzyme was slightly stimulated by Na+, K+, NH4+, Ca2+ and polyamines. Mg2+ and Mn2+ were without effect on the enzyme activity.
Collapse
Affiliation(s)
- H Kumagai
- Faculty of Pharmaceutical Sciences, Chiba University, Japan
| | | | | | | | | | | | | |
Collapse
|
30
|
Katiyar SK, Agarwal R, Wang ZY, Bhatia AK, Mukhtar H. (-)-Epigallocatechin-3-gallate in Camellia sinensis leaves from Himalayan region of Sikkim: inhibitory effects against biochemical events and tumor initiation in Sencar mouse skin. Nutr Cancer 1992; 18:73-83. [PMID: 1408948 DOI: 10.1080/01635589209514207] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Recently, we and others showed that the components of green tea may be useful cancer chemopreventive agents. It has been suggested that (-)-epigallocatechin-3-gallate (EGCG), the major constituent in green tea, may possess antitumor-promoting and/or anticarcinogenic effects in rodent tumor bioassay systems. During the chemical analysis of various green tea products, we found a traditionally preserved preparation of green tea used by tribes in the Himalayan region of Sikkim, India that was rich in EGCG. EGCG was isolated from this tea product, and its inhibitory effects were evaluated against the binding of topically applied 3H-labeled polycyclic aromatic hydrocarbons (PAHs) to epidermal DNA and 12-O-tetradecanoylphorbol-13-acetate (TPA) caused induction of epidermal ornithine decarboxylase (ODC) activity in Sencar mice, the short-term markers of tumor initiation and tumor promotion, respectively. Preapplication of EGCG resulted in significant inhibition (p less than 0.05) in the binding of [3H]PAH to epidermal DNA. Similarly, the topical application of EGCG resulted in significant inhibition (p less than 0.005) in TPA-caused induction of epidermal ODC activity. In further studies, we assessed the anti-skin tumor-initiating effect of EGCG in Sencar mice in an initiation-promotion protocol. The application of EGCG before challenge with 7,12-dimethylbenz[a]anthracene as tumor initiator resulted in significant reduction both in percentage of mice with tumors and number of tumors per mouse compared with a non-EGCG-pretreated group of animals. The results of the present study suggest that the green tea preparation from Sikkim may be a good source for the isolation of EGCG and that this compound may have significant potential as a cancer chemopreventive agent.
Collapse
Affiliation(s)
- S K Katiyar
- Department of Dermatology, University Hospitals of Cleveland, Case Western Reserve University, OH
| | | | | | | | | |
Collapse
|
31
|
Wang ZY, Agarwal R, Zhou ZC, Bickers DR, Mukhtar H. Antimutagenic and antitumorigenic activities of nordihydroguaiaretic acid. Mutat Res 1991; 261:153-62. [PMID: 1719406 DOI: 10.1016/0165-1218(91)90062-q] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Nordihydroguaiaretic acid (NDGA), which occurs in the resinous exudates of many plants is used as an antioxidant in fats and oils. In this study we show that NDGA inhibited the mutagenicity of methyl methanesulfonate, benzo[a]pyrene (BP), 2-aminofluorene, and aflatoxin B1 in Salmonella typhimurium strain TA100 or TA98 in the absence and presence of rat hepatic microsomal activation system. The addition of NDGA during and after nitrosation of methylurea (MU) resulted in a dose-dependent inhibition of mutagenicity induced by nitrosation products of MU. In a two-stage skin tumorigenesis protocol using 7,12-dimethylbenz[a]anthracene (DMBA) as the initiating agent followed by twice weekly applications of 12-O-tetradecanoylphorbol-13-acetate (TPA) as tumor promoter, pretreatment of animals with NDGA prior to DMBA application, afforded significant protection against skin tumorigenicity in female SENCAR mice. In additional studies, skin application of NDGA also inhibited the binding of topically applied [3H]BP and [3H]DMBA to epidermal DNA. When assessed in the anti-tumor promotion protocol, pretreatment of animals with NDGA before each application of TPA in DMBA-initiated mouse skin, resulted in 72% decrease in the total number of tumors when compared to non-NDGA pretreated animals. The possible mechanism(s) of the antimutagenic and anti-tumorigenic activities may be due to the multiple effects of NDGA as inhibitor of the carcinogen metabolism and DNA-adduct formation, scavenger of carcinogen free radicals, and as inhibitor of TPA-induced ornithine decarboxylase activity.
Collapse
Affiliation(s)
- Z Y Wang
- Department of Dermatology, Skin Diseases Research Center, University Hospitals of Cleveland, Case Western Reserve University, OH
| | | | | | | | | |
Collapse
|
32
|
Bablanian R, Goswami SK, Esteban M, Banerjee AK, Merrick WC. Mechanism of selective translation of vaccinia virus mRNAs: differential role of poly(A) and initiation factors in the translation of viral and cellular mRNAs. J Virol 1991; 65:4449-60. [PMID: 2072458 PMCID: PMC248885 DOI: 10.1128/jvi.65.8.4449-4460.1991] [Citation(s) in RCA: 29] [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
We have recently demonstrated that the poly(A) moieties of short RNAs obtained from both in vitro transcription and from vaccinia virus (VV)-infected cells exhibit dissimilar effects on the in vitro translation of cellular and VV mRNAs (R. Bablanian, G. Coppola, P. Masters, and A. K. Banerjee, Virology 148:375-380, 1986; M. J. Su and R. Bablanian, Virology 179:679-693, 1990). In the present study, we have investigated the roles of poly(A), m7GTP, and initiation factors in the mechanism of selective translation of VV mRNAs. The effects of unfractionated poly(A) [termed poly(A)un, with various chain lengths up to 3,000 nucleotides] and a 150- to 300-nucleotide fraction of synthetic poly(A) [termed poly(A)150-300] on the translation of HeLa cell mRNAs and early and late VV mRNAs were studied. Both the poly(A)un and the poly(A)150-300 completely inhibited the translation of HeLa cell mRNAs obtained from total cytoplasmic RNA in the nuclease-treated reticulocyte lysates. Viral mRNAs from total cytoplasmic RNA also were slightly inhibited (15 to 38%) by the poly(A)un, whereas the poly(A)150-300 had no significant effect on their translation. The translation of oligo(dT)-cellulose-selected HeLa mRNAs was as sensitive to inhibition by poly(A)150-300 as the mRNAs found in total cytoplasmic RNA. However, the translations of oligo(dT)-cellulose-selected viral mRNAs become more sensitive to the inhibitory effect of poly(A)150-300 than the translations of viral mRNAs found in the total cytoplasmic RNA. Both HeLa and VV mRNAs became more resistant to the poly(A)-mediated inhibition when these mRNAs were deadenylated, but the relative resistance to inhibition by poly(A)150-300 of deadenylated VV mRNAs was much greater than that of HeLa cell mRNAs. The translation of VV mRNAs was significantly less inhibited than the translation of HeLa mRNAs when the cap analog, m7GTP, was added to the cell-free system. The inhibition of HeLa cell mRNA translation by both poly(A)un and poly(A)150-300 was completely restored when poly(A)-binding protein (PAB) was added to the cell-free translational system. The addition of eukaryotic initiation factor 4A (eIF-4A) did not restore translation when poly(A)un was used to inhibit translation; however, inhibition by poly(A)150-300 was significantly reversed by this initiation factor. The reversal of poly (A)-mediated inhibition of HeLa cell mRNA translation was additive when PAB was used together with eIF-4A. Early VV mRNA translation was only slightly inhibited by poly(A)un (15%), and this inhibition was completely reversed by either PAB or eIF-4A.(ABSTRACT TRUNCATED AT 400 WORDS)
Collapse
Affiliation(s)
- R Bablanian
- Department of Microbiology and Immunology, SUNY Health Science Center, Brooklyn 11203
| | | | | | | | | |
Collapse
|
33
|
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
|
34
|
Agarwal R, Wang ZY, Mukhtar H. Inhibition of mouse skin tumor-initiating activity of DMBA by chronic oral feeding of glycyrrhizin in drinking water. Nutr Cancer 1991; 15:187-93. [PMID: 1907733 DOI: 10.1080/01635589109514126] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Licorice (Glycyrrhiza glabra), a Mediterranean plant, has been used as an antidote, demulcent, and elixir folk medicine for generations in China. The main water-soluble constituent of licorice is glycyrrhizin (GL), which has been shown to possess several pharmacological properties. In this study, we show that oral feeding of GL to Sencar mice resulted in substantial protection against skin tumorigenesis caused by 7,12-dimethyl-benz [a]anthracene (DMBA) initiation and 12-O-tetradecanoylphorbol-13-acetate (TPA) promotion. The latent period prior to the onset of tumor development was considerably prolonged in GL-fed animals compared with animals not fed GL and resulted in significant decrease in the number of tumors per mouse, during and at the termination of the experiment. Oral feeding of GL in drinking water also resulted in inhibition in the binding of topically applied [3H]benzo[a]pyrene and [3H]DMBA to epidermal DNA. The possible mechanism(s) of the antitumor-initiating activity may be due to the involvement of GL as inhibitor of the carcinogen metabolism followed by DNA adduct formation. Our results suggest that GL possesses considerable antitumorigenic activity and could prove useful in protecting some forms of human cancer.
Collapse
Affiliation(s)
- R Agarwal
- Department of Dermatology, University Hospitals of Cleveland, OH
| | | | | |
Collapse
|
35
|
Su MJ, Bablanian R. Polyadenylated RNA sequences from vaccinia virus-infected cells selectively inhibit translation in a cell-free system: structural properties and mechanism of inhibition. Virology 1990; 179:679-93. [PMID: 1700540 DOI: 10.1016/0042-6822(90)90135-e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The mechanism of vaccinia virus-induced selective inhibition of host cell protein synthesis was studied in a nonpermissive (Chinese hamster ovary, CHO) and in a permissive mouse cell line ( L cells). Small polyadenylated RNAs obtained from uninfected and infected cells were fractionated into six size classes by polyacrylamide gel electrophoresis. The RNAs from the first two largest fractions (greater than 500 nucleotide, nt) were translated into some low-molecular-weight polypeptides, whereas, the RNAs from the remaining fractions (400-500, 300-400, 200-300, and 100-200 nt) had no translational activity in reticulocyte lysates. When these nontranslating polyadenylated short sequences (POLADS) were added to the cell-free system together with HeLa cell mRNAs, translation was inhibited from 70%, by the 400- to 500-nt fraction, to about 20%, by the 100- to 200-nt fraction. The degree of inhibition of protein synthesis was clearly dependent on the size of POLADS. The translation of vaccinia virus mRNAs in the cell-free system was inhibited by about 25% with the 400- to 500-nt fraction, by 5% with the 300- to 400-nt fraction, while the smaller size POLADS had no inhibitory effect. The inhibition of HeLa cell and vaccinia virus mRNA translation by POLADS was reversed by the simultaneous addition of oligo(dT) to the cell-free system. POLADS were also obtained from uninfected cells, but they inhibited the translation of HeLa cell and vaccinia virus mRNAs to a much lesser extent. The removal of the poly(A) moiety from POLADS by treatment with ribonuclease H and oligo(dT) abolished their inhibitory effect on HeLa cell mRNA translation. The average length of the poly(A) tails of POLADS obtained from infected cells was longer than that of POLADS from normal cells. Inhibition of HeLa cell mRNA translation mediated by POLADS in the cell-free system was reversed (approximately 70%) by addition of crude initiation factors (ribosomal salt wash, RSW). Significantly, inhibition of translation of POLADS was reversed (greater than 90%) by addition of purified poly(A) binding protein (PAB). Purified initiation factor 4A (eIF-4A) also reversed this inhibition, but to a lesser extent than RSW and PAB. Our results show that the translation of vaccinia virus mRNAs is resistant to POLADS, suggesting that POLADS, by virtue of their long poly(A) tails, may sequester PAB and thus, play a role in selective inhibition.
Collapse
Affiliation(s)
- M J Su
- Department of Microbiology and Immunology, SUNY, Brooklyn 11203
| | | |
Collapse
|
36
|
Affiliation(s)
- B Moss
- Laboratory of Viral Diseases, National Institutes of Health, Bethesda, MD 20892
| |
Collapse
|
37
|
Shuman S, Moss B. Bromouridine Triphosphate Inhibits Transcription Termination and mRNA Release by Vaccinia Virions. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(19)30087-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
38
|
Wang ZY, Cheng SJ, Zhou ZC, Athar M, Khan WA, Bickers DR, Mukhtar H. Antimutagenic activity of green tea polyphenols. Mutat Res 1989; 223:273-85. [PMID: 2500594 DOI: 10.1016/0165-1218(89)90120-1] [Citation(s) in RCA: 182] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
For centuries green tea has been a widely consumed beverage throughout the world. It is known to contain a number of pharmacologically active compounds. In this study water extracts of green tea (WEGT) and their major constituents, green tea polyphenols (GTP), were examined for antimutagenic activity. WEGT and GTP were found to significantly inhibit the reverse mutation induced by benzo[alpha]pyrene (BP), aflatoxin B1 (AFB1), 2-aminofluorene, and methanol extracts of coal tar pitch in Salmonella typhimurium TA100 and/or TA98 in the presence of a rat-liver microsomal activation system. GTP also inhibited gene forward mutation in V79 cells treated with AFB1 and BP, and also decreased the frequency of sister-chromatid exchanges and chromosomal aberrations in V79 cells treated with AFB1. The addition of GTP during and after nitrosation of methylurea resulted in a dose-dependent inhibition of mutagenicity. Studies to define the mechanism of the antimutagenic activity of GTP suggest that it may affect carcinogen metabolism, DNA adduct formation, the interaction of ultimate carcinogen or the scavenging of free radicals.
Collapse
Affiliation(s)
- Z Y Wang
- Department of Dermatology, Case Western Reserve University, Cleveland, OH 44106
| | | | | | | | | | | | | |
Collapse
|
39
|
Bablanian R, Goswami SK, Esteban M, Banerjee AK. Selective inhibition of protein synthesis by synthetic and vaccinia virus-core synthesized poly(riboadenylic acids). Virology 1987; 161:366-73. [PMID: 2825410 DOI: 10.1016/0042-6822(87)90129-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Studies were undertaken to compare the effect of poly(A)s from various sources on selective inhibition of protein synthesis in the reticulocyte lysate system programmed with viral and cellular mRNAs. RNA synthesized in vitro by vaccinia virus cores in the presence of only ATP inhibited overall HeLa cell polypeptide synthesis by over 80% with a minimal effect on translation of vaccinia virus mRNAs. Hybridization of the [alpha-32P]AMP-labeled RNA made in vitro by vaccinia virus cores in the presence of only ATP, showed no complementary to HindIII restriction fragments of vaccinia virus DNA indicating that the in vitro product was poly(A). Fractionation of synthetic and core-synthesized poly(A) into three size classes showed that the larger the size of poly(A), the greater its inhibitory activity of protein synthesis in the cell-free system. Inhibition of translation of mRNAs from vaccinia virus-infected HeLa cells was also observed in the presence of poly(A). However, virus-induced polypeptide synthesis was more resistant to the effect of poly(A) than were cellular polypeptides. Oligo(dT) when added to the reticulocyte lysate system was capable of reversing the inhibition of protein synthesis caused by both core-synthesized poly(A) and core-transcribed RNAs. These results indicate that poly(A) synthesized by the virion-associated enzyme has inhibitory properties similar to those of synthetic poly(A).
Collapse
Affiliation(s)
- R Bablanian
- Department of Microbiology and Immunology, SUNY, Health Sciences Center at Brooklyn 11203
| | | | | | | |
Collapse
|
40
|
Mukhtar H, Asokan P, Das M, Santella RM, Bickers DR. Benzo(a)pyrene diol epoxide-I-DNA adduct formation in the epidermis and lung of SENCAR mice following topical application of crude coal tar. Cancer Lett 1986; 33:287-94. [PMID: 3100019 DOI: 10.1016/0304-3835(86)90068-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The levels of benzo[a]pyrene diol epoxide-I-deoxyguanosine (BPDE-I-dG) adduct formation in epidermis and lung of SENCAR mice following the topical application of benzo[a]pyrene (BP) alone, crude coal tar (CCT) alone, and the two combined were determined in an enzyme linked immunosorbent (ELISA) assay using monoclonal antibodies. Topical application of two doses of BP (20 micrograms) at 72-h intervals, with sacrifice 24 h later resulted in the formation of 197 fmol and 205 fmol BPDE-I-dG adducts per mg DNA in epidermis and lung, respectively. Topical application of 0.5 ml CCT alone resulted in the formation of 278 fmol and 410 fmol BPDE-I-dG adducts per mg DNA in epidermis and lung, respectively. Simultaneous topical application of 20 micrograms BP and CCT (0.1-0.5 ml) resulted in substantially lower BPDE-I-dG adducts in the epidermis as well as in the lung. Our results suggest that CCT may contain inhibitors of carcinogen-DNA adduct formation and that topical application of CCT produces greater effects on DNA-adduct formation in lung than in epidermis. Thus the cancer-causing potency of the polycyclic aromatic hydrocarbons (PAHs) in CCT may be reduced by other anticarcinogenic constituents present in CCT and systemic absorption of carcinogenic PAHs in CCT applied to skin might have tumorigenic effects in other tissues.
Collapse
|
41
|
Das M, Mukhtar H, DelTito BJ, Marcelo CL, Bickers DR. Clotrimazole, an inhibitor of benzo[a]pyrene metabolism and its subsequent glucuronidation, sulfation, and macromolecular binding in BALB/c mouse cultured keratinocytes. J Invest Dermatol 1986; 87:4-10. [PMID: 3755152 DOI: 10.1111/1523-1747.ep12523369] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The effect of the antifungal imidazole compound, clotrimazole, on the metabolism of benzo[a]pyrene (BP) was studied in cultured keratinocytes prepared from BALB/c mouse epidermis. Varying concentrations of clotrimazole added to the cultured keratinocytes resulted in a dose-dependent inhibition of the activities of the microsomal cytochrome P-450-dependent monooxygenases aryl hydrocarbon hydroxylase and 7-ethoxycoumarin O-deethylase. The major organic solvent-soluble metabolites of BP identified in the cultured cells were trans-7,8-dihydro-7,8-dihydroxybenzo[a]pyrene (BP-7,8-diol), 9-hydroxybenzo[a]pyrene (9-OH-BP), and 3-hydroxybenzo[a]pyrene (3-OH-BP), although small amounts of trans-4,5-dihydro-4,5-dihydroxybenzo[a]pyrene, BP-quinones, and trans-9,10-dihydroxybenzo[a]pyrene were also present. The major organic solvent-extractable metabolites of BP found in the extracellular culture medium were primarily the diols with smaller quantities of phenols and quinones. The major water-soluble metabolites of BP present both intracellularly and extracellularly were glucuronide conjugates of 3-OH-BP, 9-OH-BP, and benzo[a]pyrene-3,6-dione and to a lesser extent sulfate conjugates (primarily of the BP-7,8-diol). Clotrimazole inhibited the generation of organic solvent-soluble and water-soluble conjugates in a dose-dependent manner. The in vitro metabolism of BP by microsomes prepared from control and benz[a]anthracene (BA)-induced cultured keratinocytes was also inhibited by clotrimazole with greater inhibitory effect on BA-induced keratinocytes especially with respect to the formation of diols and quinones. The enzyme-mediated covalent binding of BP to mouse keratinocyte DNA and protein was also substantially diminished by clotrimazole in a dose-dependent fashion. These results indicate that clotrimazole, a widely used drug for the management of a variety of superficial dermatophyte infections of the skin, is a potent inhibitor of cytochrome P-450-dependent transformation of polycyclic aromatic hydrocarbons in cultured murine keratinocytes. This system offers a convenient approach for studies as inhibitors of carcinogen metabolism in the epidermis.
Collapse
|
42
|
Moussatché N. Polyamines stimulate DNA-dependent RNA synthesis catalyzed by vaccinia virus. BIOCHIMICA ET BIOPHYSICA ACTA 1985; 826:113-20. [PMID: 4052428 DOI: 10.1016/0167-4781(85)90116-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The RNA synthesis in purified vaccinia virus can occur in the presence of either Mg2+ or Mn2+ if polyamine (spermidine or spermine) is present in the assay system. Under our assay conditions transcription was linear up to 30 min and the RNAs synthesized had a sedimentation coefficient of about 8 to 12 S. We also prepared a virus extract from purified vaccinia virus and tested for in vitro transcription. The soluble transcription system was dependent on the addition of exogenous DNA and single-stranded DNA was a more effective template than double-stranded. In the presence of polyamine and Mg2+ or Mn2+ the viral RNA polymerase was active in the transcription of total native vaccinia DNA and a small fragment cloned in pBR322.
Collapse
|
43
|
Esteban M, Cabrera CV, Holowczak JA. Biochemical and electron microscopic studies of the transcription of vaccinia DNA by RNA polymerase from Escherichia coli: localization and characterization of transcriptional complexes. J Virol Methods 1985; 12:111-33. [PMID: 3908465 DOI: 10.1016/0166-0934(85)90013-8] [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] [Indexed: 01/07/2023]
Abstract
We used the prokaryotic Escherichia coli RNA polymerase to determine if vaccinia DNA might provide recognition sites for the bacterial binding and initiation. Electron microscopic studies of the interaction of E. coli RNA polymerase with vaccinia DNA and molecular hybridization analysis of the transcription products formed after 3 or 5 min of in vitro incubation showed that: there were 30-40 sites on the template where the polymerase could bind and initiate cRNA synthesis; the entire coding capacity of the genome was utilized for cRNA synthesis; transcription was asymmetric; cRNA molecules were similar in size to the transcripts synthesized by the vaccinia virus RNA polymerase in vitro and in vivo; cRNA contains sequences in common with 'pre-early', 'early', and 'late' in vivo RNA; 'self-annealing' of cRNA in the presence or absence of RNA synthesized in vitro by the virion associated RNA polymerase showed that less than 1% dsRNA product could be detected suggesting that initially the same strand(s) was copied by the viral and bacterial enzymes; no differences in the frequency with which sequences represented in the Hind III fragments of vaccinia DNA were transcripted with time of in vitro incubation could be detected. These findings strongly suggest that the bacterial enzyme might recognize truly viral promotors. With extended in vitro incubations of the E. coli RNA polymerase with vaccinia DNA the control of transcription was found to diminish. This was correlated with an increase in the size of the transcripts and the synthesis of significant amounts of self-complementary RNA, indicating that symmetrical transcription was occurring. The dsRNA species recovered after self-annealing the cRNA from a 30 min in vitro reaction mixture were found to contain sequences which hybridized to some portion of all the Hind III restriction fragments of vaccinia DNA. The methods described here might be useful for the localization and characterization of promotor sequences in the genome of vaccinia virus, as well as for studies on sequence conservation between members of the Poxvirus genus.
Collapse
|
44
|
Das M, Bickers DR, Santella RM, Mukhtar H. Altered patterns of cutaneous xenobiotic metabolism in UVB-induced squamous cell carcinoma in SKH-1 hairless mice. J Invest Dermatol 1985; 84:532-6. [PMID: 3998503 DOI: 10.1111/1523-1747.ep12273527] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cutaneous xenobiotic metabolizing enzymes including aryl hydrocarbon hydroxylase (AHH), 7-ethoxycoumarin O-deethylase (ECD), epoxide hydrolase (EH) and glutathione S-transferase (GST) activities were examined in SKH hairless mice chronically irradiated with UVB to induce squamous cell carcinoma (SCC). Enzyme activities in irradiated tumor-bearing skin were compared to those present in the skin of nonirradiated control animals as well as in unirradiated non-tumor bearing skin sites of the SCC-bearing mice. The inducibility of skin AHH and ECD in each set of animals was assessed following a single topical application of coal tar (1 ml/100 g). Enzyme-mediated binding of [3H]benzo(a)pyrene (BP) and its metabolite 7 beta,8 alpha-dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (BPDE-I) to epidermal DNA was also evaluated. Basal AHH and ECD activities in microsomes from UVB-irradiated SCC-bearing dorsal skin were 4.6- and 4.8-fold lower than those in dorsal skin of nonirradiated control animals. Enzyme activities in non-tumor bearing ventral skin from the UVB-irradiated SCC-bearing mice also were 2.2 to 2.8-fold lower as compared to activities in the nonirradiated control animals. The reduction in AHH activity paralleled the levels of enzyme-mediated binding of radiolabeled BP metabolites and of BPDE-I to epidermal DNA. GST activity was found to be increased (173%) in non-tumor bearing ventral skin of UVB-irradiated mice whereas no difference in activity between SCC-bearing dorsal skin and dorsal skin of control animals could be detected. EH activity was unchanged in each group of animals. Treatment with topically applied coal tar resulted in higher inducibility of AHH and ECD in both SCC-bearing (13-fold) as well as in non-tumor skin sites (6-fold) of UVB-irradiated mice than in skin of control animals (3-fold). Coal tar application also increased the covalent binding of [3H]BP and of the metabolite BPDE-I to skin DNA. This was greater in SCC-bearing dorsal skin (119-129%) than in nonirradiated skin of control animals (48-62%). Our studies suggest that the metabolism of BP by cutaneous cytochrome P-450 dependent monooxygenases is impaired in skin of mice irradiated chronically with UVB. The higher inducibility of these monooxygenases by topically applied coal tar and the enhancement of the associated enzyme-mediated covalent binding of BP metabolites and BPDE-I to epidermal DNA indicate that repetitive exposure of mammalian skin to UVB radiation can profoundly alter the activity and the inducibility of drug and carcinogen metabolizing enzymes.(ABSTRACT TRUNCATED AT 400 WORDS)
Collapse
|
45
|
Mukhtar H, Das M, Del Tito BJ, Bickers DR. Epidermal benzo[a]pyrene metabolism and DNA-binding in Balb/C mice: inhibition by ellagic acid. Xenobiotica 1984; 14:527-31. [PMID: 6506765 DOI: 10.3109/00498258409151442] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Topical application of ellagic acid, a common plant phenol, to control or to 3-methylcholanthrene (3-MC) pretreated Balb/C mice, resulted in significant inhibition of hepatic and epidermal microsomal aryl hydrogen hydroxylase activity, and of benzo[a]pyrene (BP) binding to epidermal and hepatic DNA in vivo. In vitro addition of ellagic acid (0.25 mM) to epidermal microsomal incubation systems from either control or 3-MC-treated animals resulted in 62-75% inhibition of BP binding to calf thymus DNA. These studies suggest that ellagic acid could prove useful in understanding and/or modulating polyaromatic hydrocarbon carcinogenesis.
Collapse
|
46
|
Huvos P. Transcription in vaccinia virus cores. The RNA produced during the first round of transcription does not differ from RNA transcribed in subsequent rounds. BIOCHIMICA ET BIOPHYSICA ACTA 1984; 782:34-40. [PMID: 6722157 DOI: 10.1016/0167-4781(84)90103-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
RNA was synthesized in vitro in vaccinia virus cores for times sufficiently short that only the first round of transcription took place. This RNA was compared to RNA synthesized for longer times (which is mainly comprised of reinitiated RNA) by hybridization to fragments of vaccinia virus DNA obtained with several different restriction endonucleases. Under the conditions studied, the composition of mRNA produced during the first round of transcription was the same as that produced in subsequent (reinitiated) rounds. Thus, there is no special arrangement of polymerase molecules within the cores that would allow, in the first round of transcription, for the synthesis of mRNAs distinct from those made in subsequent rounds of transcription. Thus, attachment of polymerase molecules to DNA is likely to occur during preincubation in a way similar to that during reinitiation.
Collapse
|
47
|
Mukhtar H, Das M, Del Tito BJ, Bickers DR. Protection against 3-methylcholanthrene-induced skin tumorigenesis in Balb/C mice by ellagic acid. Biochem Biophys Res Commun 1984; 119:751-7. [PMID: 6324772 DOI: 10.1016/s0006-291x(84)80314-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Topical application of ellagic acid, a naturally occurring dietary plant phenol, to Balb/C mice resulted in significant protection against 3-methylcholanthrene (MCA)-induced skin tumorigenesis. Ellagic acid was found to be an effective inhibitor of tumor formation whether the tumor data are considered as percent mice with tumors, cumulative number of tumors, tumors per mouse or tumors per tumor bearing animal as a function of the number of weeks on test. By 8, 10, 12, 14, and 16 weeks of testing, the number of tumors per mouse in the group receiving MCA alone was 2.0, 3.4, 4.0, 4.9 and 5.3, respectively, whereas the corresponding numbers in the group receiving MCA plus 2 mumol ellagic acid were 0, 0.3, 0.4, 0.6 and 1.2, respectively. At the termination of the experiment (16 weeks) aryl hydrocarbon hydroxylase (AHH) activity in skin and liver and the extent of 3H-BP-binding to skin, liver and lung DNA were determined and both of these parameters were found to be significantly inhibited in the animals treated with ellagic acid. These results indicate that ellagic acid can inhibit the metabolism of polyaromatic hydrocarbons and modulate skin carcinogenesis induced by these chemicals.
Collapse
|
48
|
Esteban M, Cabrera CV, Holowczak JA. Electron microscopic studies of transcriptional complexes released from vaccinia cores during RNA-synthesis in vitro: methods for fractionation of transcriptional complexes. J Virol Methods 1983; 7:73-92. [PMID: 6313727 DOI: 10.1016/0166-0934(83)90094-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Electron microscopic (EM) and biochemical methods were employed to study the transcriptional complexes present in detergent lysates of vaccinia virus cores actively synthesizing RNA in vitro. When processed and examined in the EM, 14 'transcriptional sites' could be observed on full-length DNA templates. Fractionation of lysates by equilibrium density centrifugation in CsSO4, chromatography on hydroxyapatite columns or by sedimentation in sucrose gradients, allowed isolation of DNA templates associated with transcripts but these manipulations often resulted in fragmentation of the DNA template or promoted the release of transcripts from the template. It is suggested that RNA transcripts remain associated with the template in regions of supercoiling. These regions, in turn, may be maintained by DNA-protein interactions which are compromised as the transcriptional complexes are fractionated and purified.
Collapse
|
49
|
Del Tito BJ, Mukhtar H, Bickers DR. Inhibition of epidermal metabolism and DNA-binding of benzo[a]pyrene by ellagic acid. Biochem Biophys Res Commun 1983; 114:388-94. [PMID: 6309171 DOI: 10.1016/0006-291x(83)91639-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Ellagic acid, a common plant phenol, was shown to be a potent inhibitor of epidermal microsomal aryl hydrocarbon hydroxylase (AHH) activity in vitro, and of benzo[a]pyrene (BP)-binding to both calf thymus DNA in vitro and to epidermal DNA in vivo. The in vitro addition of ellagic acid (0.25-2.0 microM) resulted in a dose-dependent inhibition of AHH activity in epidermal microsomes prepared from control or carcinogen-treated animals. The I50 of ellagic acid for epidermal AHH was 1.0 microM making it the most potent inhibitor of epidermal AHH yet identified. In vitro addition of ellagic acid to microsomal suspensions prepared from control or coal tar-treated animals resulted in 90% inhibition of BP-binding to calf thymus DNA. Application of ellagic acid to the skin (0.5-10.0 mumol/10 gm body wt) caused a dose-dependent inhibition of BP-binding to epidermal DNA. Our results suggest that phenolic compounds such as ellagic acid may prove useful in modulating the risk of cutaneous cancer from environmental chemicals.
Collapse
|
50
|
Abstract
Purified virions of milker's nodule virus, a parapoxvirus, were shown to contain an RNA polymerase, a nucleotide phosphohydrolase, and a protein kinase associated with or encapsulated within the DNA-containing core of the virus. In vitro, the activated viral RNA polymerase transcribed only 7 to 8% of the genome, in the form of 8S to 14S polyadenylated RNA molecules which were complementary to sequences present in milker's nodule virus DNA but not vaccinia virus DNA or DNA prepared from the host cells in which the virus was propagated. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis showed that in vitro, the activated viral protein kinase phosphorylated viral polypeptides of 95, 60, 33.5, 15, and 13.8 kilodaltons.
Collapse
|