Cell-cycle-dependent localization of human cytomegalovirus UL83 phosphoprotein in the nucleolus and modulation of viral gene expression in human embryo fibroblasts in vitro

2011 ◽  
Vol 112 (1) ◽  
pp. 307-317 ◽  
Author(s):  
Maria-Cristina Arcangeletti ◽  
Isabella Rodighiero ◽  
Prisco Mirandola ◽  
Flora De Conto ◽  
Silvia Covan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Human Cytomegalovirus ◽  
Human Embryo ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Embryo Fibroblasts ◽  
Cycle Dependent

scholarly journals MicroRNA miR-21 Attenuates Human Cytomegalovirus Replication in Neural Cells by Targeting Cdc25a

2014 ◽  
Vol 89 (2) ◽  
pp. 1070-1082 ◽  
Author(s):  
Ya-Ru Fu ◽  
Xi-Juan Liu ◽  
Xiao-Jun Li ◽  
Zhang-zhou Shen ◽  
Bo Yang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Stem Cells ◽  
Birth Defects ◽  
Human Cytomegalovirus ◽  
Hcmv Infection ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Gene Products ◽  
Hcmv Replication

ABSTRACTCongenital human cytomegalovirus (HCMV) infection is a leading cause of birth defects, primarily manifesting as neurological disorders. HCMV infection alters expression of cellular microRNAs (miRs) and induces cell cycle arrest, which in turn modifies the cellular environment to favor virus replication. Previous observations found that HCMV infection reduces miR-21 expression in neural progenitor/stem cells (NPCs). Here, we show that infection of NPCs and U-251MG cells represses miR-21 while increasing the levels of Cdc25a, a cell cycle regulator and known target of miR-21. These opposing responses to infection prompted an investigation of the relationship between miR-21, Cdc25a, and viral replication. Overexpression of miR-21 in NPCs and U-251MG cells inhibited viral gene expression, genome replication, and production of infectious progeny, while shRNA-knockdown of miR-21 in U-251MG cells increased viral gene expression. In contrast, overexpression of Cdc25a in U-251MG cells increased viral gene expression and production of infectious progeny and overcame the inhibitory effects of miR-21 overexpression. Three viral gene products—IE1, pp71, and UL26—were shown to inhibit miR-21 expression at the transcriptional level. These results suggest that Cdc25a promotes HCMV replication and elevation of Cdc25a levels after HCMV infection are due in part to HCMV-mediated repression of miR-21. Thus, miR-21 is an intrinsic antiviral factor that is modulated by HCMV infection. This suggests a role for miR-21 downregulation in the neuropathogenesis of HCMV infection of the developing CNS.IMPORTANCEHuman cytomegalovirus (HCMV) is a ubiquitous pathogen and has very high prevalence among population, especially in China, and congenital HCMV infection is a major cause for birth defects. Elucidating virus-host interactions that govern HCMV replication in neuronal cells is critical to understanding the neuropathogenesis of birth defects resulting from congenital infection. In this study, we confirm that HCMV infection downregulates miR-21 but upregulates Cdc25a. Further determined the negative effects of cellular miRNA miR-21 on HCMV replication in neural progenitor/stem cells and U-251MG glioblastoma/astrocytoma cells. More importantly, our results provide the first evidence that miR-21 negatively regulates HCMV replication by targeting Cdc25a, a vital cell cycle regulator. We further found that viral gene products of IE1, pp71, and UL26 play roles in inhibiting miR-21 expression, which in turn causes increases in Cdc25a and benefits HCMV replication. Thus, miR-21 appears to be an intrinsic antiviral factor that represents a potential target for therapeutic intervention.

scholarly journals Human Cytomegalovirus 86-Kilodalton IE2 Protein Blocks Cell Cycle Progression in G1

1999 ◽  
Vol 73 (11) ◽  
pp. 9274-9283 ◽  
Author(s):  
Lüder Wiebusch ◽  
Christian Hagemeier
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Human Cytomegalovirus ◽  
Transcriptional Activation ◽  
Cell Cycle Progression ◽  
Biological Activities ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Proliferating Cells ◽  
Activation Domains

ABSTRACT The 86-kDa IE2 protein of human cytomegalovirus (HCMV) is an important regulator of viral and host cell gene expression. Still, besides its function as a transcription factor, little is known about the biological activities of IE2. Here, we show that IE2 can induce a G1 arrest in several different cell lines, including HCMV-permissive U-373 cells. The known transcriptional activation domains of IE2 are dispensable for G1 arrest, favoring a posttranscriptional mechanism mediating this cell cycle effect. We show that like human primary fibroblasts U-373 cells arrest in G1 upon infection with HCMV. This G1 arrest occurs within 24 h after infection and in proliferating cells depends on viral gene expression. Our data therefore suggest that IE2 is at least partially responsible for blocking the transition from G1 to S phase, which is induced when cells are infected with HCMV.

scholarly journals Human Cytomegalovirus Subverts the Functions of Monocytes, Impairing Chemokine-Mediated Migration and Leukocyte Recruitment

2006 ◽  
Vol 80 (15) ◽  
pp. 7578-7589 ◽  
Author(s):  
Giada Frascaroli ◽  
Stefania Varani ◽  
Barbara Moepps ◽  
Christian Sinzger ◽  
Maria Paola Landini ◽  
...  
Keyword(s):  
Gene Expression ◽  
Human Cytomegalovirus ◽  
Chemokine Receptors ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Host Immune System ◽  
Infected Cells ◽  
And Function ◽  
A Site

ABSTRACT Despite their role in innate and adaptive immunity, during human cytomegalovirus (HCMV) infection, monocytes are considered to be an important target of infection, a site of latency, and vehicles for virus dissemination. Since chemokine receptors play crucial roles in monocyte activation and trafficking, we investigated the effects of HCMV on their expression and function. By using endotheliotropic strains of HCMV, we obtained high rates (roughly 50%) of in vitro-infected monocytes but only restricted viral gene expression. At 24 h after infection, while the chemokine receptors CX3CR and CCR7 were unaffected, CCR1, CCR2, CCR5, and CXCR4 were downmodulated on the cell surface and retained intracellularly. Structural components of the viral particles, but not viral gene expression or soluble factors released from infected cells, accounted for the changed localization of the receptor molecules and for the block of chemokine-driven migration. HCMV-infected monocytes indeed became unresponsive to inflammatory and homeostatic chemokines, although the basal cell motility and responsiveness to N-formyl-Met-Leu-Phe were unaffected or slightly increased. The production of inflammatory mediators responsible for the recruitment of other immune cells was also hampered by HCMV. Whereas endothelial and fibroblast cells infected by HCMV efficiently recruited leukocytes, infected monocytes were unable to recruit lymphocytes, monocytes, and neutrophils. Our data further highlight the complex level of interference exerted by HCMV on the host immune system.

scholarly journals Human cytomegalovirus transcriptome activity differs during replication in human fibroblast, epithelial and astrocyte cell lines

2012 ◽  
Vol 93 (5) ◽  
pp. 1046-1058 ◽  
Author(s):  
James C. Towler ◽  
Bahram Ebrahimi ◽  
Brian Lane ◽  
Andrew J. Davison ◽  
Derrick J. Dargan
Keyword(s):  
Gene Expression ◽  
Human Cytomegalovirus ◽  
Growth Kinetics ◽  
Viral Gene Expression ◽  
Cell Types ◽  
Viral Gene ◽  
Genome Replication ◽  
Cell Type ◽  
Low Passage ◽  
Temporal Expression Pattern

Broad cell tropism contributes to the pathogenesis of human cytomegalovirus (HCMV), but the extent to which cell type influences HCMV gene expression is unclear. A bespoke HCMV DNA microarray was used to monitor the transcriptome activity of the low passage Merlin strain of HCMV at 12, 24, 48 and 72 h post-infection, during a single round of replication in human fetal foreskin fibroblast cells (HFFF-2s), human retinal pigmented epithelial cells (RPE-1s) and human astrocytoma cells (U373MGs). In order to correlate transcriptome activity with concurrent biological responses, viral cytopathic effect, growth kinetics and genomic loads were examined in the three cell types. The temporal expression pattern of viral genes was broadly similar in HFFF-2s and RPE-1s, but dramatically different in U373MGs. Of the 165 known HCMV protein-coding genes, 41 and 48 were differentially regulated in RPE-1s and U373MGs, respectively, compared with HFFF-2s, and 22 of these were differentially regulated in both RPE-1s and U373MGs. In RPE-1s, all differentially regulated genes were downregulated, but, in U373MGs, some were down- and others upregulated. Differentially regulated genes were identified among the immediate-early, early, early late and true-late viral gene classes. Grouping of downregulated genes according to function at landmark stages of the replication cycle led to the identification of potential bottleneck stages (genome replication, virion assembly, and virion maturation and release) that may account for cell type-dependent viral growth kinetics. The possibility that cell type-specific differences in expressed cellular factors are responsible for modulation of viral gene expression is discussed.

scholarly journals HCMV exploits STING signaling and counteracts IFN and ISG induction to facilitate dendritic cell infection

2022 ◽  
Author(s):  
Bibiana Costa ◽  
Jennifer Becker ◽  
Tobias Krammer ◽  
Felix Mulenge ◽  
Verónica Durán ◽  
...  
Keyword(s):  
Gene Expression ◽  
Viral Gene Expression ◽  
Productive Infection ◽  
Viral Gene ◽  
Human Pathogen ◽  
Cell Infection ◽  
Complex Interactions ◽  
Life Threatening ◽  
Immunocompromised Hosts

Abstract Human cytomegalovirus (HCMV) is a widespread obligatory human pathogen causing life-threatening disease in immunocompromised hosts. Myeloid cells such as monocyte-derived dendritic cells (moDCs) are targets of HCMV. Here, we performed single-cell RNA sequencing, which revealed infection of most moDCs upon in vitro HCMV exposure, whereas only a fraction of them initiated viral gene expression. We identified three moDC subsets, of which CD1a−/CD86− cells showed the highest susceptibility. Upon HCMV entry, STING activation not only induced IFN-β, but also promoted viral gene expression. Upon progression of infection, IFN-β but not IFN-λ1 expression was inhibited. Similarly, ISG expression was initially induced and then shut off and thus allowed productive infection. Increased viral gene expression was associated with the induction of several pro- (RHOB, HSP1A1, DNAJB1) and anti-viral (RNF213, TNFSF10, IFI16) genes. Thus, moDC permissiveness to HCMV depends on complex interactions between virus sensing, regulation of IFNs/ISGs and viral gene expression.

scholarly journals Kaposi's Sarcoma-Associated Herpesvirus Induces Sustained NF-κB Activation during De Novo Infection of Primary Human Dermal Microvascular Endothelial Cells That Is Essential for Viral Gene Expression

2007 ◽  
Vol 81 (8) ◽  
pp. 3949-3968 ◽  
Author(s):  
Sathish Sadagopan ◽  
Neelam Sharma-Walia ◽  
Mohanan Valiya Veettil ◽  
Hari Raghu ◽  
Ramu Sivakumar ◽  
...  
Keyword(s):  
Gene Expression ◽  
Growth Factors ◽  
De Novo ◽  
Viral Gene Expression ◽  
Angiogenic Factors ◽  
Viral Gene ◽  
Kshv Infection ◽  
Time Points ◽  
Lytic Genes

ABSTRACT In vitro Kaposi's sarcoma-associated herpesvirus (KSHV) infection of primary human dermal microvascular endothelial (HMVEC-d) cells and human foreskin fibroblast (HFF) cells is characterized by the induction of preexisting host signal cascades, sustained expression of latency-associated genes, transient expression of a limited number of lytic genes, and induction of several cytokines, growth factors, and angiogenic factors. Since NF-κB is a key molecule involved in the regulation of several of these factors, here, we examined NF-κB induction during de novo infection of HMVEC-d and HFF cells. Activation of NF-κB was observed as early as 5 to 15 min postinfection by KSHV, and translocation of p65-NF-κB into nuclei was detected by immunofluorescence assay, electrophoretic mobility shift assay, and p65 enzyme-linked immunosorbent assay. IκB phosphorylation inhibitor (Bay11-7082) reduced this activation significantly. A sustained moderate level of NF-κB induction was seen during the observed 72 h of in vitro KSHV latency. In contrast, high levels of ERK1/2 activation at earlier time points and a moderate level of activation at later times were observed. p38 mitogen-activated protein kinase was activated only at later time points, and AKT was activated in a cyclic manner. Studies with UV-inactivated KSHV suggested a role for virus entry stages in NF-κB induction and a requirement for KSHV viral gene expression in sustained induction. Inhibition of NF-κB did not affect target cell entry by KSHV but significantly reduced the expression of viral latent open reading frame 73 and lytic genes. KSHV infection induced the activation of several host transcription factors, including AP-1 family members, as well as several cytokines, growth factors, and angiogenic factors, which were significantly affected by NF-κB inhibition. These results suggest that during de novo infection, KSHV induces sustained levels of NF-κB to regulate viral and host cell genes and thus possibly regulates the establishment of latent infection.

scholarly journals Lytic infection of permissive cells with human cytomegalovirus is regulated by an intrinsic ‘pre-immediate-early’ repression of viral gene expression mediated by histone post-translational modification

2009 ◽  
Vol 90 (10) ◽  
pp. 2364-2374 ◽  
Author(s):  
Ian J. Groves ◽  
Matthew B. Reeves ◽  
John H. Sinclair
Keyword(s):  
Gene Expression ◽  
Human Cytomegalovirus ◽  
Chromatin Structure ◽  
Viral Gene Expression ◽  
Lytic Infection ◽  
Immediate Early ◽  
Late Gene ◽  
Viral Gene ◽  
Gene Promoters ◽  
Late Gene Expression

Human cytomegalovirus (HCMV) lytic gene expression occurs in a regulated cascade, initiated by expression of the viral major immediate-early (IE) proteins. Transcribed from the major IE promoter (MIEP), the major IE genes regulate viral early and late gene expression. This study found that a substantial proportion of infecting viral genomes became associated with histones immediately upon infection of permissive fibroblasts at low m.o.i. and these histones bore markers of repressed chromatin. As infection progressed, however, the viral MIEP became associated with histone marks, which correlate with the known transcriptional activity of the MIEP at IE time points. Interestingly, this chromatin-mediated repression of the MIEP at ‘pre-IE’ times of infection could be overcome by inhibition of histone deacetylases, as well as by infection at high m.o.i., and resulted in a temporal advance of the infection cycle by inducing premature viral early and late gene expression and DNA replication. As well as the MIEP, and consistent with previous observations, the viral early and late promoters were also initially associated with repressive chromatin. However, changes in histone modifications around these promoters also occurred as infection progressed, and this correlated with the known temporal regulation of the viral early and late gene expression cascade. These data argue that the chromatin structure of all classes of viral genes are initially repressed on infection of permissive cells and that the chromatin structure of HCMV gene promoters plays an important role in regulating the time course of viral gene expression during lytic infection.

scholarly journals Expression of varicella-zoster virus VLT-ORF63 fusion transcript induces broad viral gene expression during reactivation from neuronal latency

2020 ◽  
Author(s):  
Werner J. D. Ouwendijk ◽  
Daniel P. Depledge ◽  
Labchan Rajbhandari ◽  
Tihana Lenac Rovis ◽  
Stipan Jonjic ◽  
...  
Keyword(s):  
Gene Expression ◽  
Varicella Zoster Virus ◽  
Viral Gene Expression ◽  
Fusion Transcript ◽  
Viral Gene ◽  
Reading Frame ◽  
Varicella Zoster ◽  
Rapid Amplification

SummaryVaricella-zoster virus (VZV) establishes lifelong neuronal latency in most humans world-wide, reactivating in one-third to cause herpes zoster and occasionally chronic pain. How VZV establishes, maintains and reactivates from latency is largely unknown. Latent VZV gene expression is restricted to VZV latency-associated transcript (VLT) and open reading frame 63 (ORF63) in naturally VZV-infected human trigeminal ganglia (TG). Notably, these transcript levels positively correlated suggesting co-regulated transcription during latency. Here, we used direct RNA-sequencing to identify fusion transcripts that combine VLT and ORF63 loci (VLT-ORF63) and are expressed during both lytic and latent VZV infections. Furthermore, real-time PCR, RNA in situ hybridization and 5’ rapid amplification of cDNA ends (RACE) all confirmed VLT-ORF63, but not canonical ORF63, expression in human TG. During lytic infection, one of the two major VLT-ORF63 isoforms encodes a novel fusion protein combining VLT and ORF63 proteins (pVLT-ORF63). In vitro, VLT is transcribed in latently VZV-infected human sensory neurons, whereas VLT-ORF63 expression is induced by reactivation stimuli. Moreover, the pVLT-ORF63-encoding VLT-ORF63 isoform induced transcription of lytic VZV genes. Collectively, our findings show that VZV expresses a unique set of VLT-ORF63 transcripts, potentially involved in the transition from latency to lytic VZV infection.

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