scholarly journals Rescue of Recombinant Marburg Virus from cDNA Is Dependent on Nucleocapsid Protein VP30

2006 ◽  
Vol 80 (2) ◽  
pp. 1038-1043 ◽  
Author(s):  
Sven Enterlein ◽  
Viktor Volchkov ◽  
Michael Weik ◽  
Larissa Kolesnikova ◽  
Valentina Volchkova ◽  
...  
Keyword(s):  
Nucleocapsid Protein ◽  
Ebola Virus ◽  
Marburg Virus ◽  
Wild Type Virus ◽  
Binding Motif ◽  
Wild Type ◽  
Virus Particles ◽  
Virus Recombinant ◽  
Infected Cells ◽  
Virus Recovery

ABSTRACT Here we report recovery of infectious Marburg virus (MARV) from a full-length cDNA clone. Compared to the wild-type virus, recombinant MARV showed no difference in terms of morphology of virus particles, intracellular distribution in infected cells, and growth kinetics. The nucleocapsid protein VP30 of MARV and Ebola virus (EBOV) contains a Zn-binding motif which is important for the function of VP30 as a transcriptional activator in EBOV, whereas its role for MARV is unclear. It has been reported previously that MARV VP30 is able to support transcription in an EBOV-specific minigenome system. When the Zn-binding motif was destroyed, MARV VP30 was shown to be inactive in the EBOV system. While it was not possible to rescue recombinant MARV when the VP30 plasmid was omitted from transfection, MARV VP30 with a destroyed Zn-binding motif and EBOV VP30 were able to mediate virus recovery. In contrast, rescue of recombinant EBOV was not supported by EBOV VP30 containing a mutated Zn-binding domain.

scholarly journals The Morphology and Composition of Influenza A Virus Particles Are Not Affected by Low Levels of M1 and M2 Proteins in Infected Cells

2005 ◽  
Vol 79 (12) ◽  
pp. 7926-7932 ◽  
Author(s):  
Svetlana V. Bourmakina ◽  
Adolfo García-Sastre
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Virus Particles ◽  
M1 Protein ◽  
Infected Cells ◽  
Low Levels ◽  
Viral Components

ABSTRACT We generated a recombinant influenza A virus (Mmut) that produced low levels of matrix (M1) and M2 proteins in infected cells. Mmut virus propagated to significantly lower titers than did wild-type virus in cells infected at low multiplicity. By contrast, virion morphology and incorporation of viral proteins and vRNAs into virus particles were similar to those of wild-type virus. We propose that a threshold amount of M1 protein is needed for the assembly of viral components into an infectious particle and that budding is delayed in Mmut virus-infected cells until sufficient levels of M1 protein accumulate at the plasma membrane.

scholarly journals Conserved Motifs within Ebola and Marburg Virus VP40 Proteins Are Important for Stability, Localization, and Subsequent Budding of Virus-Like Particles

2009 ◽  
Vol 84 (5) ◽  
pp. 2294-2303 ◽  
Author(s):  
Yuliang Liu ◽  
Luis Cocka ◽  
Atsushi Okumura ◽  
Yong-An Zhang ◽  
J. Oriol Sunyer ◽  
...  
Keyword(s):  
Self Assembly ◽  
Mammalian Cells ◽  
Ebola Virus ◽  
Intracellular Localization ◽  
Gel Filtration ◽  
Point Mutations ◽  
Marburg Virus ◽  
Structure Stability ◽  
Wild Type ◽  
Virus Like Particles

ABSTRACT The filovirus VP40 protein is capable of budding from mammalian cells in the form of virus-like particles (VLPs) that are morphologically indistinguishable from infectious virions. Ebola virus VP40 (eVP40) contains well-characterized overlapping L domains, which play a key role in mediating efficient virus egress. L domains represent only one component required for efficient budding and, therefore, there is a need to identify and characterize additional domains important for VP40 function. We demonstrate here that the 96LPLGVA101 sequence of eVP40 and the corresponding 84LPLGIM89 sequence of Marburg virus VP40 (mVP40) are critical for efficient release of VP40 VLPs. Indeed, deletion of these motifs essentially abolished the ability of eVP40 and mVP40 to bud as VLPs. To address the mechanism by which the 96LPLGVA101 motif of eVP40 contributes to egress, a series of point mutations were introduced into this motif. These mutants were then compared to the eVP40 wild type in a VLP budding assay to assess budding competency. Confocal microscopy and gel filtration analyses were performed to assess their pattern of intracellular localization and ability to oligomerize, respectively. Our results show that mutations disrupting the 96LPLGVA101 motif resulted in both altered patterns of intracellular localization and self-assembly compared to wild-type controls. Interestingly, coexpression of either Ebola virus GP-WT or mVP40-WT with eVP40-ΔLPLGVA failed to rescue the budding defective eVP40-ΔLPLGVA mutant into VLPs; however, coexpression of eVP40-WT with mVP40-ΔLPLGIM successfully rescued budding of mVP40-ΔLPLGIM into VLPs at mVP40-WT levels. In sum, our findings implicate the LPLGVA and LPLGIM motifs of eVP40 and mVP40, respectively, as being important for VP40 structure/stability and budding.

scholarly journals A live-cell imaging system for visualizing the transport of Marburg virus nucleocapsid-like structures

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Yuki Takamatsu ◽  
Olga Dolnik ◽  
Takeshi Noda ◽  
Stephan Becker
Keyword(s):  
Live Cell Imaging ◽  
Intracellular Transport ◽  
Actin Polymerization ◽  
Ebola Virus ◽  
Cell Imaging ◽  
Temporal Dynamics ◽  
Imaging System ◽  
Marburg Virus ◽  
Live Cell ◽  
Infected Cells

Abstract Background Live-cell imaging is a powerful tool for visualization of the spatio-temporal dynamics of moving signals in living cells. Although this technique can be utilized to visualize nucleocapsid transport in Marburg virus (MARV)- or Ebola virus-infected cells, the experiments require biosafety level-4 (BSL-4) laboratories, which are restricted to trained and authorized individuals. Methods To overcome this limitation, we developed a live-cell imaging system to visualize MARV nucleocapsid-like structures using fluorescence-conjugated viral proteins, which can be conducted outside BSL-4 laboratories. Results Our experiments revealed that nucleocapsid-like structures have similar transport characteristics to those of nucleocapsids observed in MARV-infected cells, both of which are mediated by actin polymerization. Conclusions We developed a non-infectious live cell imaging system to visualize intracellular transport of MARV nucleocapsid-like structures. This system provides a safe platform to evaluate antiviral drugs that inhibit MARV nucleocapsid transport.

scholarly journals Interwoven Roles of Cyclin D3 and cdk4 Recruited by ICP0 and ICP4 in the Expression of Herpes Simplex Virus Genes

2010 ◽  
Vol 84 (19) ◽  
pp. 9709-9717 ◽  
Author(s):  
Maria Kalamvoki ◽  
Bernard Roizman
Keyword(s):  
Cyclin D3 ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Nuclear Retention ◽  
Enhanced Expression ◽  
Infected Cells ◽  
Cytoplasmic Accumulation ◽  
Simplex Virus ◽  
Cdk4 Inhibitor

ABSTRACT Elsewhere this laboratory reported that (i) ICP0 interacts with cyclin D3 but not D1 or D2. The 3 cyclins independently partially rescue ΔICP0 mutants. (ii) Interaction with cyclin D3 is required for the switch from nuclear to cytoplasmic accumulation of ICP0. (iii) In infected cells cdk4 is activated whereas cdk2 is not. Inhibition of cdk4 results in nuclear retention of ICP0. Overexpression of cyclin D3 reverses the effect of the inhibitor. Here we report the following. (i) cdk4 interacts with ICP0, ICP4, and possibly with ICP8. This interaction is required to recruit cdk4 initially to ND10 and later to the viral replication compartments. (ii) cdk4 inhibitor I reduced or delayed the transcription and ultimately translation of mRNAs of ICP4, ICP27, or ICP8 and to a lesser extent that of the ICP0 gene in wild-type virus-infected cells. (iii) Overexpression of cyclin D3 resulted in a more rapid transcription of these genes. In the presence of inhibitor, the rates of accumulation of the products of these genes resemble those of wild-type virus in the absence of inhibitor. (iv) Overexpression of cyclin D3 also results in mobilization of cdk6 in nuclei of infected cells. We conclude that ICP0 encodes a function that enhances the recruitment of cyclin D3 to ND10 structures to activate cdk4 and that ICP0 along with other viral proteins recruits cdk4 to ND10 structures and ultimately to replication compartments for enhanced expression of viral genes and viral DNA synthesis.

scholarly journals Herpes Simplex Virus 1 Induces Cytoplasmic Accumulation of TIA-1/TIAR and both Synthesis and Cytoplasmic Accumulation of Tristetraprolin, Two Cellular Proteins That Bind and Destabilize AU-Rich RNAs

2004 ◽  
Vol 78 (16) ◽  
pp. 8582-8592 ◽  
Author(s):  
Audrey Esclatine ◽  
Brunella Taddeo ◽  
Bernard Roizman
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Mutant Virus ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Herpes Simplex Virus 1 ◽  
Infected Cells ◽  
Cytoplasmic Accumulation ◽  
Simplex Virus

ABSTRACT Herpes simplex virus 1 causes a shutoff of cellular protein synthesis through the degradation of RNA that is mediated by the virion host shutoff (Vhs) protein encoded by the UL41 gene. We reported elsewhere that the Vhs-dependent degradation of RNA is selective, and we identified RNAs containing AU-rich elements (AREs) that were upregulated after infection but degraded by deadenylation and progressive 3′-to-5′ degradation. We also identified upregulated RNAs that were not subject to Vhs-dependent degradation (A. Esclatine, B. Taddeo, L. Evans, and B. Roizman, Proc. Natl. Acad. Sci. USA 101:3603-3608, 2004). Among the latter was the RNA encoding tristetraprolin, a protein that binds AREs and is known to be associated with the degradation of RNAs containing AREs. Prompted by this observation, we examined the status of the ARE binding proteins tristetraprolin and TIA-1/TIAR in infected cells. We report that tristetraprolin was made and accumulated in the cytoplasm of wild-type virus-infected human foreskin fibroblasts as early as 2 h and in HEp-2 cells as early as 6 h after infection. The amounts of tristetraprolin that accumulated in the cytoplasm of cells infected with a mutant virus lacking UL41 were significantly lower than those in wild-type virus-infected cells. The localization of tristetraprolin was not modified in cells infected with a mutant lacking the gene encoding infected cell protein 4 (ICP4). TIA-1 and TIAR are two other proteins that are associated with the regulation of ARE-containing RNAs and that normally reside in nuclei. In infected cells, they started to accumulate in the cytoplasm after 6 h of infection. In cells infected with the mutant virus lacking UL41, TIA-1/TIAR accumulated in the cytoplasm in granular structures reminiscent of stress granules in a significant percentage of the cells. In addition, an antibody to tristetraprolin coprecipitated the Vhs protein from lysates of cells late in infection. The results indicate that the Vhs-dependent degradation of ARE-containing RNAs correlates with the transactivation, cytoplasmic accumulation, and persistence of tristetraprolin in infected cells.

scholarly journals NKG2D-mediated Natural Killer Cell Protection Against Cytomegalovirus Is Impaired by Viral gp40 Modulation of Retinoic Acid Early Inducible 1 Gene Molecules

2003 ◽  
Vol 197 (10) ◽  
pp. 1245-1253 ◽  
Author(s):  
Melissa Lodoen ◽  
Kouetsu Ogasawara ◽  
Jessica A. Hamerman ◽  
Hisashi Arase ◽  
Jeffrey P. Houchins ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Natural Killer ◽  
Nk Cell ◽  
Critical Role ◽  
Killer Cell ◽  
Cell Surface Expression ◽  
Wild Type Virus ◽  
Wild Type ◽  
Infected Cells

Natural killer (NK) cells play a critical role in the innate immune response against cytomegalovirus (CMV) infections. Although CMV encodes several gene products committed to evasion of adaptive immunity, viral modulation of NK cell activity is only beginning to be appreciated. A previous study demonstrated that the mouse CMV m152-encoded gp40 glycoprotein diminished expression of ligands for the activating NK cell receptor NKG2D on the surface of virus-infected cells. Here we have defined the precise ligands that are affected and have directly implicated NKG2D in immune responses to CMV infection in vitro and in vivo. Murine CMV (MCMV) infection potently induced transcription of all five known retinoic acid early inducible 1 (RAE-1) genes (RAE-1α, RAE-1β, RAE-1δ, RAE-1ε, and RAE-1γ), but not H-60. gp40 specifically down-regulated the cell surface expression of all RAE-1 proteins, but not H-60, and diminished NK cell interferon γ production against CMV-infected cells. Consistent with previous findings, a m152 deletion mutant virus (Δm152) was less virulent in vivo than the wild-type Smith strain of MCMV. Treatment of BALB/c mice with a neutralizing anti-NKG2D antibody before infection increased titers of Δm152 virus in the spleen and liver to levels seen with wild-type virus. These experiments demonstrate that gp40 impairs NK cell recognition of virus-infected cells through disrupting the RAE-1–NKG2D interaction.

scholarly journals Role of Herpes Simplex Virus ICP27 in the Degradation of mRNA by Virion Host Shutoff RNase

2010 ◽  
Vol 84 (19) ◽  
pp. 10182-10190 ◽  
Author(s):  
Brunella Taddeo ◽  
Weiran Zhang ◽  
Bernard Roizman
Keyword(s):  
Mutant Virus ◽  
Structural Proteins ◽  
Wild Type Virus ◽  
Tegument Protein ◽  
Wild Type ◽  
Virion Host Shutoff ◽  
Infected Cells ◽  
Host Shutoff ◽  
Simplex Virus

ABSTRACT The virion host shutoff (VHS) RNase tegument protein released into cells by infecting virus has two effects. Preexisting stable mRNAs (e.g., GAPDH [glyceraldehyde-3-phosphate dehydrogenase]) are rapidly degraded. Stress response RNAs containing AU-rich elements (AREs) in the 3′ untranslated region (3′UTR) are deadenylated and cleaved, but the cleavage products persist for hours, in contrast to the short half-lives of ARE-containing mRNAs in uninfected cells. At late times, the VHS RNase is neutralized by the viral structural proteins VP16 and VP22. A recent study (J. A. Corcoran, W. L. Hsu, and J. R. Smiley, J. Virol. 80:9720-9729, 2006) reported that, at relatively late times after infection, ARE RNAs are rapidly degraded in cells infected with ΔICP27 mutant virus and concluded that ICP27 “stabilizes” ARE mRNAs. We report the following. (i) The rates of degradation of ARE mRNA at early times (3 h) after infection with the wild type or the ΔICP27 mutant virus are virtually identical, and hence ICP27 plays no role in this process. (ii) In noncomplementing cells, VHS RNase or VP22 is not synthesized. Therefore, the only VHS that is active is brought into cells by the ΔICP27 mutant. (ii) The VHS RNase brought into the cells by the ΔICP27 virus is reduced in potency relative to that of wild-type virus. Hence the rapid degradation of ARE mRNAs noted in ΔICP27 mutant-infected cells at late times is similar to that taking place in mock-infected or in ΔVHS RNase mutant-virus-infected cells and does not by itself support the hypothesis that ICP27 stabilizes ARE mRNAs. (iii) Concurrently, we present the first evidence that VHS RNase interacts with ICP27 most likely when bound to cap- and poly(A)-binding proteins, respectively.

scholarly journals Replication-Competent Controlled Herpes Simplex Virus

2015 ◽  
Vol 89 (20) ◽  
pp. 10668-10679 ◽  
Author(s):  
David C. Bloom ◽  
Joyce Feller ◽  
Peterjon McAnany ◽  
Nuria Vilaboa ◽  
Richard Voellmy
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Traditional Approach ◽  
Wild Type Virus ◽  
Infection Model ◽  
Wild Type ◽  
Infected Cells ◽  
Simplex Virus ◽  
Gene Switch ◽  
Hsv 1

ABSTRACTWe present the development and characterization of a replication-competent controlled herpes simplex virus 1 (HSV-1). Replication-essential ICP4 and ICP8 genes of HSV-1 wild-type strain 17syn+ were brought under the control of a dually responsive gene switch. The gene switch comprises (i) a transactivator that is activated by a narrow class of antiprogestins, including mifepristone and ulipristal, and whose expression is mediated by a promoter cassette that comprises an HSP70B promoter and a transactivator-responsive promoter and (ii) transactivator-responsive promoters that drive the ICP4 and ICP8 genes. Single-step growth experiments in different cell lines demonstrated that replication of the recombinant virus, HSV-GS3, is strictly dependent on an activating treatment consisting of administration of a supraphysiological heat dose in the presence of an antiprogestin. The replication-competent controlled virus replicates with an efficiency approaching that of the wild-type virus from which it was derived. Essentially no replication occurs in the absence of activating treatment or if HSV-GS3-infected cells are exposed only to heat or antiprogestin. These findings were corroborated by measurements of amounts of viral DNA and transcripts of the regulated ICP4 gene and the glycoprotein C (gC) late gene, which was not regulated. Similar findings were made in experiments with a mouse footpad infection model.IMPORTANCEThe alphaherpesviruses have long been considered vectors for recombinant vaccines and oncolytic therapies. The traditional approach uses vector backbones containing attenuating mutations that restrict replication to ensure safety. The shortcoming of this approach is that the attenuating mutations tend to limit both the immune presentation and oncolytic properties of these vectors. HSV-GS3 represents a novel type of vector that, when activated, replicates with the efficiency of a nonattenuated virus and whose safety is derived from deliberate, stringent regulation of multiple replication-essential genes. By directing activating heat to the region of virus administration, replication is strictly confined to infected cells within this region. The requirement for antiprogestin provides an additional level of safety, ensuring that virus replication cannot be triggered inadvertently. Replication-competent controlled vectors such as HSV-GS3 may have the potential to be superior to conventional attenuated HSV vaccine and oncolytic vectors without sacrificing safety.

Evaluation of orf virus (ORFV) isolation in continuous lamb testis cells (OA3.Ts) and development of a co-culture method with infected cells to increase infectivity

2016 ◽  
Author(s):  
Nawab Nashirudddullah ◽  
Debesh Chandra Pathak ◽  
Nagendra Nath Barman ◽  
Jafrin Ara Ahmed ◽  
Gitika Rajbongshi ◽  
...  
Keyword(s):  
Culture Method ◽  
Vaccine Virus ◽  
Orf Virus ◽  
Wild Type Virus ◽  
Wild Type ◽  
Cytoplasmic Inclusions ◽  
Modified Method ◽  
Culture Cells ◽  
Infected Cells ◽  
Foetal Lamb

Continuous foetal lamb testis cells OA3.Ts was used to compare the isolation of a vaccine orf virus (ORFV) strain that had been adapted to primary lamb testes cells, with scab derived wild-type/field ORFV isolates. The wild type virus showed an accelerated and exaggerated cyto-pathic effect (CPE) than the vaccine virus as has been demonstrated by immunofluorescent detection of viral antigen using ORFV monoclonal antibodies. ORFV could be successfully isolated in OA3.Ts foetal lamb testes cells and can be used for direct isolation of the virus from clinical samples.Two different methods of cell culture infection were also compared during sub-culture, one using infected supernatant as the inoculum and the other using infected cells as a modified method for infecting healthy culture cells. The present study also indicates that a higher infection can probably be achieved with inoculating infected cells together with healthy ones as a co-culture method during propagation of ORFV. This has been revealed as visibly pronounced CPE and presence of larger and multiple aggregates of cytoplasmic inclusions than cells infected with infected supernatant alone.

scholarly journals The Influenza A Virus M2 Cytoplasmic Tail Is Required for Infectious Virus Production and Efficient Genome Packaging

2005 ◽  
Vol 79 (6) ◽  
pp. 3595-3605 ◽  
Author(s):  
Matthew F. McCown ◽  
Andrew Pekosz
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Infectious Virus ◽  
Virus Production ◽  
Cytoplasmic Tail ◽  
Host Cells ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Virus Particles

ABSTRACT The M2 integral membrane protein encoded by influenza A virus possesses an ion channel activity that is required for efficient virus entry into host cells. The role of the M2 protein cytoplasmic tail in virus replication was examined by generating influenza A viruses encoding M2 proteins with truncated C termini. Deletion of 28 amino acids (M2Stop70) resulted in a virus that produced fourfold-fewer particles but >1,000-fold-fewer infectious particles than wild-type virus. Expression of the full-length M2 protein in trans restored the replication of the M2 truncated virus. Although the M2Stop70 virus particles were similar to wild-type virus in morphology, the M2Stop70 virions contained reduced amounts of viral nucleoprotein and genomic RNA, indicating a defect in vRNP packaging. The data presented indicate the M2 cytoplasmic tail plays a role in infectious virus production by coordinating the efficient packaging of genome segments into influenza virus particles.

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