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Bailer SM, Funk C, Riedl A, Ruzsics Z. Herpesviral vectors and their application in oncolytic therapy, vaccination, and gene transfer. Virus Genes 2017. [PMID: 28634751 DOI: 10.1007/s11262-017-1482-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Herpesviruses are enveloped DNA viruses that infect vertebrate cells. Their high potential cloning capacity and the lifelong persistence of their genomes in various host cells make them attractive platforms for vector-based therapy. In this review, we would like to highlight recent advances of three major areas of herpesvirus vector development and application: (i) oncolytic therapy, (ii) recombinant vaccines, and (iii) large capacity gene transfer vehicles.
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Affiliation(s)
- Susanne M Bailer
- Institute for Interfacial Engineering and Plasma Technology IGVP, University of Stuttgart, Nobelstrasse 12, 70569, Stuttgart, Germany. .,Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB, Nobelstrasse 12, 70569, Stuttgart, Germany.
| | - Christina Funk
- Institute for Interfacial Engineering and Plasma Technology IGVP, University of Stuttgart, Nobelstrasse 12, 70569, Stuttgart, Germany.,Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB, Nobelstrasse 12, 70569, Stuttgart, Germany
| | - André Riedl
- Department for Medical Microbiology and Hygiene, Institute of Virology, University Medical Center Freiburg, Hermann-Herder-Strasse 11, 79104, Freiburg, Germany.,German Center for Infection Research - DZIF, Freiburg, Germany
| | - Zsolt Ruzsics
- Department for Medical Microbiology and Hygiene, Institute of Virology, University Medical Center Freiburg, Hermann-Herder-Strasse 11, 79104, Freiburg, Germany. .,German Center for Infection Research - DZIF, Freiburg, Germany.
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Pogoda M, Bosse JB, Conzelmann KK, Koszinowski UH, Ruzsics Z. A modified screening system for loss-of-function and dominant negative alleles of essential MCMV genes. PLoS One 2014; 9:e94918. [PMID: 24733555 PMCID: PMC3986410 DOI: 10.1371/journal.pone.0094918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 03/21/2014] [Indexed: 11/30/2022] Open
Abstract
Inactivation of gene products by dominant negative mutants is a valuable tool to assign functions to yet uncharacterized proteins, to map protein-protein interactions or to dissect physiological pathways. Detailed functional and structural knowledge about the target protein would allow the construction of inhibitory mutants by targeted mutagenesis. Yet, such data are limited for the majority of viral proteins, so that the target gene needs to be subjected to random mutagenesis to identify suitable mutants. However, for cytomegaloviruses this requires a two-step screening approach, which is time-consuming and labor-intensive. Here, we report the establishment of a high-throughput suitable screening system for the identification of inhibitory alleles of essential genes of the murine cytomegalovirus (MCMV). In this screen, the site-specific recombination of a specifically modified MCMV genome was transferred from the bacterial background to permissive host cells, thereby combining the genetic engineering and the rescue test in one step. Using a reference set of characterized pM53 mutants it was shown that the novel system is applicable to identify non-complementing as well as inhibitory mutants in a high-throughput suitable setup. The new cis-complementation assay was also applied to a basic genetic characterization of pM99, which was identified as essential for MCMV growth. We believe that the here described novel genetic screening approach can be adapted for the genetic characterization of essential genes of any large DNA viruses.
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Affiliation(s)
- Madlen Pogoda
- Max von Pettenkofer-Institut, Ludwig-Maximilians-Universität, Munich, Germany
- DZIF - German Center for Infection Research, Munich, Germany
| | - Jens B. Bosse
- Max von Pettenkofer-Institut, Ludwig-Maximilians-Universität, Munich, Germany
| | | | | | - Zsolt Ruzsics
- Max von Pettenkofer-Institut, Ludwig-Maximilians-Universität, Munich, Germany
- DZIF - German Center for Infection Research, Munich, Germany
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Abstract
Bacterial artificial chromosomes (BACs) are recombinant DNA molecules designed for propagation of large and instable foreign DNA fragment in Escherichia coli. BACs are used in genetics of large DNA viruses such as herpes and baculoviruses for propagation and manipulation of complex genomic regions or even entire viral genomes in one piece. Viral genomes in BACs are ready for the advanced tools of E. coli genetics. These techniques based on homologous or site-specific recombination allow engineering of virtually any kind of genetic changes. In the recent years, BAC technology was also adapted to manipulation of adenovirus genomes and became an effective alternative to traditional genetic engineering of recombinant adenoviruses.
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Cytomegalovirus impairs antiviral CD8+ T cell immunity by recruiting inflammatory monocytes. Immunity 2012; 37:122-33. [PMID: 22840843 DOI: 10.1016/j.immuni.2012.04.014] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Revised: 04/06/2012] [Accepted: 04/19/2012] [Indexed: 12/24/2022]
Abstract
Inflammatory monocytes are key early responders to infection that contribute to pathogen-host interactions in diverse ways. Here, we report that the murine cytomegalovirus-encoded CC chemokine, MCK2, enhanced CCR2-dependent recruitment of these cells to modulate antiviral immunity, impairing virus-specific CD8(+) T cell expansion and differentiation into effector cytotoxic T lymphocytes, thus reducing the capacity to eliminate viral antigen-bearing cells and slowing viral clearance. Adoptive transfer of inflammatory monocytes into Ccr2(-/-)Ccl2(-/-) mice impaired virus antigen-specific clearance. Cytomegalovirus therefore enhances a natural CCR2-dependent immune regulatory network to modulate adaptive immunity via nitric oxide production, reminiscent of the monocytic subtype of myeloid-derived suppressor cells primarily implicated in cancer immunomodulation.
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Handke W, Krause E, Brune W. Live or let die: manipulation of cellular suicide programs by murine cytomegalovirus. Med Microbiol Immunol 2012; 201:475-86. [PMID: 22965170 DOI: 10.1007/s00430-012-0264-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 08/24/2012] [Indexed: 11/30/2022]
Abstract
Cytomegaloviruses (CMVs) are large double-stranded DNA viruses that replicate slowly and cause life-long persisting infections in their hosts. To achieve this, the CMVs had to evolve numerous countermeasures against innate and adaptive immune responses. Induction of programmed cell death is one important host defense mechanism against intracellular pathogens such as viruses. For a multicellular organism, it is advantageous to let infected cells die in order to thwart viral replication and dissemination. For a virus, by contrast, it is better to inhibit cell death and keep infected cells alive until the viral replication cycle has been completed. As a matter of fact, the CMVs encode a number of proteins devoted to interfering with different forms of programmed cell death: apoptosis and necroptosis. In this review, we summarize the known functions of the four best characterized cell death inhibitors of murine cytomegalovirus (MCMV), which are encoded by open reading frames, M36, m38.5, m41.1, and M45. The viral proteins interact with key molecules within different cell death pathways, namely caspase-8, Bax, Bak, and RIP1/RIP3. In addition, we discuss which events during MCMV infection might trigger apoptosis or necrosis and how MCMV's countermeasures compare to those of other herpesviruses. Since both, MCMV and its natural host, are amenable to genetic manipulation, the mouse model for CMV infection provides a particularly suitable system to study mechanisms of cell death induction and inhibition.
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Affiliation(s)
- Wiebke Handke
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Martinistr. 52, 20251 Hamburg, Germany
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Abstract
The gene M94 of murine cytomegalovirus (MCMV) as well as its homologues UL16 in alphaherpesviruses is involved in viral morphogenesis. For a better understanding of its role in the viral life cycle, a library of random M94 mutants was generated by modified transposon-based linker scanning mutagenesis. A comprehensive set of M94 mutants was reinserted into the MCMV genome and tested for their capacity to complement the M94 null mutant. Thereby, 34 loss-of-function mutants of M94 were identified, which were tested in a second screen for their capacity to inhibit virus replication. This analysis identified two N-terminal insertion mutants of M94 with a dominant negative effect. We compared phenotypes induced by the conditional expression of these dominant negative M94 alleles with the null phenotype of the M94 deletion. The viral gene expression cascade and the nuclear morphogenesis steps were not affected in either setting. In both cases, however, secondary envelopment did not proceed in the absence of functional M94, and capsids subsequently accumulated in the center of the cytoplasmic assembly complex. In addition, deletion of M94 resulted in a block of cell-to-cell spread. Moreover, the dominant negative mutant of M94 demonstrated a defect in interacting with M99, the UL11 homologue of MCMV.
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Autoexcision of bacterial artificial chromosome facilitated by terminal repeat-mediated homologous recombination: a novel approach for generating traceless genetic mutants of herpesviruses. J Virol 2010; 84:2871-80. [PMID: 20071577 DOI: 10.1128/jvi.01734-09] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Infectious bacterial artificial chromosomes (BACs) of herpesviruses are powerful tools for genetic manipulation. However, the presence of BAC vector sequence in the viral genomes often causes genetic and phenotypic alterations. While the excision of the BAC vector cassette can be achieved by homologous recombination between extra duplicate viral sequences or loxP site-mediated recombination, these methods either are inefficient or leave a loxP site mark in the viral genome. Here we describe the use of viral intrinsic repeat sequences, which are commonly present in herpesviral genomes, to excise the BAC vector cassette. Using a newly developed in vitro transposon-based cloning approach, we obtained an infectious BAC of rhesus rhadinovirus (RRV) strain RRV26-95 with the BAC vector cassette inserted in the terminal repeat (TR) region. We showed that the BAC vector cassette was rapidly excised upon reconstitution in cells predominantly through TR-mediated homologous recombination. Genetic and phenotypic analysis showed that the BAC-excised virus was reversed to wild-type RRV. Using this autoexcisable BAC clone, we successfully generated an RRV mutant with a deletion of Orf50, which encodes a replication and transcription activator (RTA) protein. Together, these results illustrate the usefulness of TR for genetic manipulation of herpesviruses when combined with the novel transposon-based cloning approach.
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Lemmermann NA, Podlech J, Seckert CK, Kropp KA, Grzimek NK, Reddehase MJ, Holtappels R. CD8 T-Cell Immunotherapy of Cytomegalovirus Disease in the Murine Model. IMMUNOLOGY OF INFECTION 2010. [DOI: 10.1016/s0580-9517(10)37016-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Abstract
SUMMARY Human cytomegalovirus (HCMV) is a common, medically relevant human herpesvirus. The tegument layer of herpesvirus virions lies between the genome-containing capsids and the viral envelope. Proteins within the tegument layer of herpesviruses are released into the cell upon entry when the viral envelope fuses with the cell membrane. These proteins are fully formed and active and control viral entry, gene expression, and immune evasion. Most tegument proteins accumulate to high levels during later stages of infection, when they direct the assembly and egress of progeny virions. Thus, viral tegument proteins play critical roles at the very earliest and very last steps of the HCMV lytic replication cycle. This review summarizes HCMV tegument composition and structure as well as the known and speculated functions of viral tegument proteins. Important directions for future investigation and the challenges that lie ahead are identified and discussed.
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