scholarly journals Gamma Interferon Blocks Gammaherpesvirus Reactivation from Latency

2006 ◽  
Vol 80 (1) ◽  
pp. 192-200 ◽  
Author(s):  
Ashley L. Steed ◽  
Erik S. Barton ◽  
Scott A. Tibbetts ◽  
Daniel L. Popkin ◽  
Mary L. Lutzke ◽  
...  
Keyword(s):  
Immune Surveillance ◽  
Viral Gene Expression ◽  
Gamma Interferon ◽  
Viral Gene ◽  
Herpesvirus Infection ◽  
Murine Gammaherpesvirus ◽  
Ifn Γ ◽  
Gammaherpesvirus 68 ◽  
Novel Strategy

ABSTRACT Establishment of latent infection and reactivation from latency are critical aspects of herpesvirus infection and pathogenesis. Interfering with either of these steps in the herpesvirus life cycle may offer a novel strategy for controlling herpesvirus infection and associated disease pathogenesis. Prior studies show that mice deficient in gamma interferon (IFN-γ) or the IFN-γ receptor have elevated numbers of cells reactivating from murine gammaherpesvirus 68 (γHV68) latency, produce infectious virus after the establishment of latency, and develop large-vessel vasculitis. Here, we demonstrate that IFN-γ is a powerful inhibitor of reactivation of γHV68 from latency in tissue culture. In vivo, IFN-γ controls viral gene expression during latency. Importantly, depletion of IFN-γ in latently infected mice results in an increased frequency of cells reactivating virus. This demonstrates that IFN-γ is important for immune surveillance that limits reactivation of γHV68 from latency.

scholarly journals Murine Gammaherpesvirus 68 Has Evolved Gamma Interferon and Stat1-Repressible Promoters for the Lytic Switch Gene 50

2010 ◽  
Vol 84 (7) ◽  
pp. 3711-3717 ◽  
Author(s):  
Megan M. Goodwin ◽  
Susan Canny ◽  
Ashley Steed ◽  
Herbert W. Virgin
Keyword(s):  
Viral Gene Expression ◽  
Gamma Interferon ◽  
Lytic Replication ◽  
Lytic Cycle ◽  
Viral Gene ◽  
Murine Gammaherpesvirus ◽  
Replication Gene ◽  
Ifn Γ ◽  
Gammaherpesvirus 68 ◽  
Murine Gammaherpesvirus 68

ABSTRACT Cytokines regulate viral gene expression with important consequences for viral replication and pathogenesis. Gamma interferon (IFN-γ) is a key regulator of chronic murine gammaherpesvirus 68 (γHV68) infection and a potent inhibitor of γHV68 reactivation from latency. Macrophages are the cell type that is responsive to the IFN-γ-mediated control of γHV68 reactivation; however, the molecular mechanism of this IFN-γ action is undefined. Here we report that IFN-γ inhibits lytic replication of γHV68 in primary bone marrow-derived macrophages and decreases transcript levels for the essential lytic switch gene 50. Interestingly, IFN-γ suppresses the activity of the two known gene 50 promoters, demonstrating that an inflammatory cytokine can directly regulate the promoters for the γHV68 lytic switch gene. Stat1, but not IFN-α/β signaling, is required for IFN-γ action. Moreover, Stat1 deficiency increases basal γHV68 replication, gene 50 expression, and promoter activity. Together, these data identify IFN-γ and Stat1 as being negative regulators of the γHV68 lytic cycle and raise the possibility that γHV68 maintains IFN-γ/Stat1-responsive gene 50 promoters to facilitate cell-extrinsic control over the interchange between the lytic and latent cycles.

scholarly journals Kinetics of Murine Gammaherpesvirus 68 Gene Expression following Infection of Murine Cells in Culture and in Mice

2001 ◽  
Vol 75 (11) ◽  
pp. 4955-4963 ◽  
Author(s):  
Rosemary Rochford ◽  
Mary L. Lutzke ◽  
Rosiane S. Alfinito ◽  
Anaira Clavo ◽  
Rhonda D. Cardin
Keyword(s):  
Gene Expression ◽  
Rnase Protection Assay ◽  
Viral Gene ◽  
3T3 Cells ◽  
Rnase Protection ◽  
Murine Gammaherpesvirus ◽  
Gammaherpesvirus 68 ◽  
Murine Gammaherpesvirus 68 ◽  
Kinetics Of

ABSTRACT A model system to study the pathogenesis of gammaherpesvirus infections is the infection of mice with murine gammaherpesvirus 68 (MHV-68). To define the kinetics of infection, we developed an RNase protection assay to quantitate gene expression from lytic (K3, Rta, M8, DNA polymerase [DNA pol], and gB) and candidate latency (M2, M3, M9, M11, ORF73, and ORF74) genes. All candidate latency genes were expressed during lytic infection of 3T3 cells. Four kinetic classes of transcripts were observed following infection of 3T3 cells: immediate-early (K3, Rta, M8, and ORF73), early (DNA pol), early-late (M3, M11, and ORF74), and late (M2, M9, and gB). To assess the kinetics of viral gene expression in vivo, lungs, spleens, and mediastinal lymph nodes (MLN) were harvested from MHV-68-infected mice. All transcripts were expressed between 3 and 6 days postinfection (dpi) in the lungs. In the spleen, K3, M3, M8, and M9 transcripts were expressed between 10 and 16 dpi when latency is established. The K3, M3, M8, M9, and M11 transcripts were detected in the MLN from 2 through 16 dpi. This is the first demonstration of MHV-68 gene expression in the MLN. Importantly, our data showed that MHV-68 has different kinetics of gene expression at different sites of infection. Furthermore, we demonstrated that K3, a gene recently shown to encode a protein that downregulates major histocompatibility complex class I on the surface of cells, is expressed during latency, which argues for a role of K3 in immune evasion during latent infection.

scholarly journals Elevated Chemokine Responses Are Maintained in Lungs after Clearance of Viral Infection

2002 ◽  
Vol 76 (20) ◽  
pp. 10518-10523 ◽  
Author(s):  
Jason B. Weinberg ◽  
Mary L. Lutzke ◽  
Stacey Efstathiou ◽  
Steven L. Kunkel ◽  
Rosemary Rochford
Keyword(s):  
Gene Expression ◽  
Viral Infection ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Murine Gammaherpesvirus ◽  
Chemokine Expression ◽  
Gammaherpesvirus 68 ◽  
Murine Gammaherpesvirus 68

ABSTRACT We observed two patterns of chemokine expression in the lungs of mice infected with murine gammaherpesvirus 68: peaks of chemokine expression correlated with or occurred after the peak of viral gene expression. Chemokine expression remained elevated through 29 days postinfection.

scholarly journals RNA-guided gene editing of the murine gammaherpesvirus 68 genome reduces infectious virus production

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252313
Author(s):  
Hui-Chen Chang Foreman ◽  
Varvara Kirillov ◽  
Gabrielle Paniccia ◽  
Demetra Catalano ◽  
Trevor Andrunik ◽  
...  
Keyword(s):  
Gene Editing ◽  
Particle Production ◽  
De Novo ◽  
Model Systems ◽  
Viral Gene ◽  
Gene Target ◽  
Murine Gammaherpesvirus ◽  
Gammaherpesvirus 68 ◽  
Murine Gammaherpesvirus 68

Epstein-Barr virus (EBV) and Kaposi sarcoma herpesvirus (KSHV) are cancer-causing viruses that establish lifelong infections in humans. Gene editing using the Cas9-guideRNA (gRNA) CRISPR system has been applied to decrease the latent load of EBV in human Burkitt lymphoma cells. Validating the efficacy of Cas9-gRNA system in eradicating infection in vivo without off-target effects to the host genome will require animal model systems. To this end, we evaluated a series of gRNAs against individual genes and functional genomic elements of murine gammaherpesvirus 68 (MHV68) that are both conserved with KSHV and important for the establishment of latency or reactivation from latency in the host. gRNA sequences against ORF50, ORF72 and ORF73 led to insertion, deletion and substitution mutations in these target regions of the genome in cell culture. Murine NIH3T3 fibroblast cells that stably express Cas9 and gRNAs to ORF50 were most resistant to replication upon de novo infection. Latent murine A20 B cell lines that stably express Cas9 and gRNAs against MHV68 were reduced in their reactivation by approximately 50%, regardless of the viral gene target. Lastly, co-transfection of HEK293T cells with the vector expressing the Cas9-MHV68 gRNA components along with the viral genome provided a rapid read-out of gene editing and biological impact. Combinatorial, multiplex MHV68 gRNA transfections in HEK293T cells led to near complete ablation of infectious particle production. Our findings indicate that Cas9-gRNA editing of the murine gammaherpesvirus genome has a deleterious impact on productive replication in three independent infection systems.

scholarly journals Lytic infection with murine gammaherpesvirus 68 activates host and viral RNA polymerase III promoters and enhances non-coding RNA expression

2021 ◽  
Author(s):  
Ashley N. Knox ◽  
Alice Mueller ◽  
Eva M. Medina ◽  
Eric T. Clambey ◽  
Linda F. van Dyk
Keyword(s):  
Gene Expression ◽  
Flow Cytometry ◽  
Rna Polymerase ◽  
Rna Polymerase Iii ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Murine Gammaherpesvirus ◽  
Polymerase Iii ◽  
Gammaherpesvirus 68 ◽  
Pol Iii

RNA polymerase III (pol III) transcribes multiple non-coding (nc) RNAs that are essential for cellular function. Pol III-dependent transcription is also engaged during certain viral infections, including the gammaherpesviruses (γHVs), where pol III-dependent viral ncRNAs promote pathogenesis. Additionally, several host ncRNAs are upregulated during γHV infection and play integral roles in pathogenesis by facilitating viral establishment and gene expression. Here, we sought to investigate how pol III promoters and transcripts are regulated during gammaherpesvirus infection using the murine gammaherpesvirus 68 (γHV68) system. To compare the transcription of host and viral pol III-dependent ncRNAs, we analyzed a series of pol III promoters for host and viral ncRNAs using a luciferase reporter optimized to measure pol III activity. We measured promoter activity from the reporter gene at the translation level via luciferase activity and at the transcription level via RT-qPCR. We further measured endogenous ncRNA expression at single cell-resolution by flow cytometry. These studies demonstrated that lytic infection with γHV68 increased the transcription from multiple host and viral pol III promoters, and further identified the ability of accessory sequences to influence both baseline and inducible promoter activity after infection. RNA flow cytometry revealed the induction of endogenous pol III-derived ncRNAs that tightly correlated with viral gene expression. These studies highlight how lytic gammaherpesvirus infection alters the transcriptional landscape of host cells to increase pol III-derived RNAs, a process that may further modify cellular function and enhance viral gene expression and pathogenesis. IMPORTANCE Gammaherpesviruses are a prime example of how viruses can alter the host transcriptional landscape to establish infection. Despite major insights into how these viruses modify RNA polymerase II-dependent generation of messenger RNAs, how these viruses influence the activity of host RNA polymerase III remains much less clear. Small non-coding RNAs produced by RNA polymerase III are increasingly recognized to play critical regulatory roles in cell biology and virus infection. Studies of RNA polymerase III dependent transcription are complicated by multiple promoter types and diverse RNAs with variable stability and processing requirements. Here, we characterized a reporter system to directly study RNA polymerase III-dependent responses during gammaherpesvirus infection and utilized single-cell flow cytometry-based methods to reveal that gammaherpesvirus lytic replication broadly induces pol III activity to enhance host and viral non-coding RNA expression within the infected cell.

scholarly journals Modulation of B-cell tolerance by Murine Gammaherpesvirus 68 infection: requirement for Orf73 viral gene expression and follicular helper T cells

Immunology ◽  
2013 ◽  
Vol 139 (2) ◽  
pp. 197-204 ◽  
Author(s):  
Stephen B. Gauld ◽  
Jessica L. De Santis ◽  
Joseph M. Kulinski ◽  
Jennifer A. McGraw ◽  
Steven M. Leonardo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Viral Gene Expression ◽  
Helper T Cells ◽  
Viral Gene ◽  
Cell Tolerance ◽  
B Cell Tolerance ◽  
Murine Gammaherpesvirus ◽  
Follicular Helper ◽  
Gammaherpesvirus 68 ◽  
Murine Gammaherpesvirus 68

scholarly journals ORF73-Null Murine Gammaherpesvirus 68 Reveals Roles for mLANA and p53 in Virus Replication

2007 ◽  
Vol 81 (21) ◽  
pp. 11957-11971 ◽  
Author(s):  
J. Craig Forrest ◽  
Clinton R. Paden ◽  
Robert D. Allen ◽  
Julie Collins ◽  
Samuel H. Speck
Keyword(s):  
Gene Expression ◽  
Cell Death ◽  
Virus Replication ◽  
Stress Responses ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Murine Gammaherpesvirus ◽  
Murine Fibroblasts ◽  
Gammaherpesvirus 68 ◽  
Murine Gammaherpesvirus 68

ABSTRACT Gammaherpesviruses establish lifelong, latent infections in host lymphocytes, during which a limited subset of viral gene products facilitates maintenance of the viral episome. Among the gamma-2-herpesvirus (rhadinovirus) subfamily, this includes expression of the conserved ORF73-encoded LANA proteins. We previously demonstrated by loss-of-function mutagenesis that the murine gammaherpesvirus 68 (MHV68) ORF73 gene product, mLANA, is required for the establishment of latency following intranasal inoculation of mice (N. J. Moorman, D. O. Willer, and S. H. Speck, J. Virol. 77:10295-10303, 2003). mLANA-deficient viruses also exhibited a defect in acute virus replication in the lungs of infected mice. The latter observation led us to examine the role of mLANA in productive viral replication. We assessed the capacity of mLANA-deficient virus (73.Stop) to replicate in cell culture at low multiplicities of infection (MOIs) and found that 73.Stop growth was impaired in murine fibroblasts but not in Vero cells. A recombinant virus expressing an mLANA-green fluorescent protein (GFP) fusion revealed that mLANA is expressed throughout the virus replication cycle. In addition, 73.Stop infection of murine fibroblasts at high MOIs was substantially more cytotoxic than infection with a genetically repaired marker rescue virus (73.MR), a phenotype that correlated with enhanced kinetics of viral gene expression and increased activation of p53. Notably, augmented cell death, viral gene expression, and p53 induction were independent of viral DNA replication. Expression of a mLANA-GFP fusion protein in fibroblasts correlated with both reduced p53 stabilization and reduced cell death following treatment with p53-inducing agonists. In agreement, accentuated cell death associated with 73.Stop infection was reduced in p53-deficient murine embryonic fibroblasts. Additionally, replication of 73.Stop in p53-deficient cells was restored to levels comparable to those of 73.MR. More remarkably, the absence of p53 led to an overall delay in replication for both 73.Stop and 73.MR viruses, which correlated with delayed viral gene expression, indicating a role for p53 in MHV68 replication. Consistent with these findings, the expression of replication-promoting viral genes was positively influenced by p53 overexpression or treatment with the p53 agonist etoposide. Overall, these data demonstrate the importance of mLANA in MHV68 replication and suggest that LANA proteins limit the induction of cellular stress responses to regulate the viral gene expression cascade and limit host cell injury.

scholarly journals Murine Gammaherpesvirus 68 Infection of Gamma Interferon-Deficient Mice on a BALB/c Background Results in Acute Lethal Pneumonia That Is Dependent on Specific Viral Genes

2009 ◽  
Vol 83 (21) ◽  
pp. 11397-11401 ◽  
Author(s):  
Katherine S. Lee ◽  
Carlyne D. Cool ◽  
Linda F. van Dyk
Keyword(s):  
Chronic Infection ◽  
Early Death ◽  
Current Data ◽  
Gamma Interferon ◽  
Murine Gammaherpesvirus ◽  
Viral Genes ◽  
Ifn Γ ◽  
Gammaherpesvirus 68 ◽  
Murine Gammaherpesvirus 68 ◽  
Deficient Mice

ABSTRACT Gamma interferon (IFN-γ) is critical for the control of chronic infection with murine gammaherpesvirus 68 (γHV68). Current data indicate that IFN-γ has a lesser role in the control of acute replication of γHV68. Here, we show that IFN-γ-deficient mice on the BALB/c genetic background poorly control acute viral replication and succumb to early death by acute pneumonia. Notably, this acute, lethal pneumonia was dependent not only on the viral dose, but also on specific viral genes including the viral cyclin gene, previously identified to be important in promoting optimal chronic infection and reactivation from latency.

scholarly journals Resistance to Acute Babesiosis Is Associated with Interleukin-12- and Gamma Interferon-Mediated Responses and Requires Macrophages and Natural Killer Cells

2003 ◽  
Vol 71 (4) ◽  
pp. 2002-2008 ◽  
Author(s):  
Irma Aguilar-Delfin ◽  
Peter J. Wettstein ◽  
David H. Persing
Keyword(s):  
Nk Cells ◽  
Gamma Interferon ◽  
Interleukin 12 ◽  
No Production ◽  
Cytokine Responses ◽  
Early Production ◽  
Ifn Γ ◽  
Crucial Part

ABSTRACT We examined the role of the cytokines gamma interferon (IFN-γ) and interleukin-12 (IL-12) in the model of acute babesiosis with the WA1 Babesia. Mice genetically deficient in IFN-γ-mediated responses (IFNGR2KO mice) and IL-12-mediated responses (Stat4KO mice) were infected with the WA1 Babesia, and observations were made on the course of infection and cytokine responses. Levels of IFN-γ and IL-12 in serum increased 24 h after parasite inoculation. The augmented susceptibility observed in IFNGR2KO and Stat-4KO mice suggests that the early IL-12- and IFN-γ-mediated responses are involved in protection against acute babesiosis. Resistance appears to correlate with an increase in nitric oxide (NO) production. In order to assess the contribution of different cell subsets to resistance against the parasite, we also studied mice lacking B cells, CD4+ T cells, NK cells, and macrophages. Mice genetically deficient in B lymphocytes or CD4+ T lymphocytes were able to mount protective responses comparable to those of immunosufficient mice. In contrast, in vivo depletion of macrophages or NK cells resulted in elevated susceptibility to the infection. Our observations suggest that a crucial part of the response that protects from the pathogenic Babesia WA1 is mediated by macrophages and NK cells, probably through early production of IL-12 and IFN-γ, and induction of macrophage-derived effector molecules like NO.

scholarly journals Viral-Mediated mRNA Degradation for Pathogenesis

Biomedicines ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 111
Author(s):  
Shujuan Du ◽  
Xiaoqing Liu ◽  
Qiliang Cai
Keyword(s):  
Gene Expression ◽  
Current Knowledge ◽  
Immune Surveillance ◽  
Viral Gene Expression ◽  
Mrna Degradation ◽  
Vital Role ◽  
Viral Gene ◽  
Antiviral Immune Response ◽  
Successful Infection ◽  
The Stability

Cellular RNA decay machinery plays a vital role in regulating gene expression by altering the stability of mRNAs in response to external stresses, including viral infection. In the primary infection, viruses often conquer the host cell’s antiviral immune response by controlling the inherently cellular mRNA degradation machinery to facilitate viral gene expression and establish a successful infection. This review summarizes the current knowledge about the diverse strategies of viral-mediated regulatory RNA shutoff for pathogenesis, and particularly sheds a light on the mechanisms that viruses evolve to elude immune surveillance during infection.

Sign in / Sign up

Export Citation Format

Share Document