Viral gene expression during the establishment of human cytomegalovirus latent infection in myeloid progenitor cells

Blood ◽  
2006 ◽  
Vol 108 (12) ◽  
pp. 3691-3699 ◽  
Author(s):  
Allen K. L. Cheung ◽  
Allison Abendroth ◽  
Anthony L. Cunningham ◽  
Barry Slobedman
Keyword(s):  
Gene Expression ◽  
Viral Genome ◽  
Latent Infection ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Time Points ◽  
Myeloid Progenitor ◽  
Viral Genes ◽  
Myeloid Progenitor Cells ◽  
Establishment Phase

AbstractHuman cytomegalovirus (HCMV) establishes and maintains a latent infection in myeloid cells and can reactivate to cause serious disease in allograft recipients. To better understand the molecular events associated with the establishment of latency, we tracked the virus following infection of primary human myeloid progenitor cells at days 1, 2, 3, 5, and 11. At all time points, the viral genome was maintained in most cells at approximately 10 copies. Infectious virus was not detected, but virus could be reactivated by extended fibroblast coculture. In contrast to wild-type HCMV, the viral genome was rapidly lost from myeloid progenitors infected with ultraviolet (UV)–inactivated virus, suggesting viral gene expression was required for efficient establishment of latency. To identify viral genes associated with the establishment phase, RNA from each time point was interrogated using custom-made HCMV gene microarrays. Using this approach, we detected expression of viral RNAs at all time points. The pattern of expression differed from that which occurs during productive infection, and decreased over time. This study provides evidence that a molecular pathway into latency is associated with expression of a unique subset of viral transcripts. Viral genes expressed during the establishment phase may serve as targets for therapies to interrupt this process.

scholarly journals Nuclear Lamina binds the EBV genome during latency and regulates viral gene expression

2021 ◽  
Author(s):  
Lisa Beatrice Caruso ◽  
Rui Guo ◽  
Sarah Boyle ◽  
Kelsey Keith ◽  
Jozef Madzo ◽  
...  
Keyword(s):  
Gene Expression ◽  
B Cells ◽  
Latent Infection ◽  
Viral Gene Expression ◽  
Nuclear Lamina ◽  
Viral Gene ◽  
Lamin A ◽  
Knock Out ◽  
Ebv Infection ◽  
Viral Genes

The Epstein Barr virus (EBV) establishes a persistent latent infection in almost 90% of the population worldwide. EBV latent infection is associated with several malignancies of epithelial and lymphoid origin. In latently infected cells, the EBV genome persists as a chromatinized episome that expresses a limited set of viral genes. Latent genes are expressed in different patterns that are referred to as latency types. Latency types coincide with varying stages of EBV infection and various malignancies. Our previous work demonstrated that latency types correlate with differences in the composition and structure of the EBV episome. Several cellular factors, including nuclear lamina, regulate chromatin composition and chromatin architecture. The interaction with nuclear lamina has already been studied in the context of EBV lytic reactivation. Still, the role of nuclear lamina in controlling EBV latency has not been investigated. Here, we reported that nuclear lamina is also another essential epigenetic regulator of the EBV episome. First, we observed that in B cells, EBV infection affects the composition of nuclear lamina by inducing the expression of Lamin A/C, and Lamin A/C is present only in EBV+ B cells expressing the Type III latency program. By ChIP-seq, we determined that lamins, Lamin B1 and Lamin A/C, bind the EBV genome, and their binding correlates with deposition of the histone repressive mark H3K9me2. By RNA-seq, we observed that the knock-out of Lamin A/C alters EBV gene expression in B cells and decreases H3K9me2 levels across the viral genome. Our data indicate that the interaction between lamins and the EBV episome contributes to the epigenetic control of viral genes expression during latency, suggesting a restrictive function of the nuclear lamina in the host response against the intrusion of viral DNA into the nucleus.

scholarly journals Tumor Necrosis Factor Alpha Induces Reactivation of Human Cytomegalovirus Independently of Myeloid Cell Differentiation following Posttranscriptional Establishment of Latency

mBio ◽  
2018 ◽  
Vol 9 (5) ◽  
Author(s):  
Eleonora Forte ◽  
Suchitra Swaminathan ◽  
Mark W. Schroeder ◽  
Jeong Yeon Kim ◽  
Scott S. Terhune ◽  
...  
Keyword(s):  
Gene Expression ◽  
Viral Gene Expression ◽  
Myeloid Cell ◽  
Viral Gene ◽  
Necrosis Factor Alpha ◽  
Myeloid Progenitor ◽  
Tnf Α ◽  
Myeloid Progenitor Cells ◽  
Factor Alpha ◽  
Lytic Genes

ABSTRACTWe used the Kasumi-3 model to study human cytomegalovirus (HCMV) latency and reactivation in myeloid progenitor cells. Kasumi-3 cells were infected with HCMV strain TB40/Ewt-GFP, flow sorted for green fluorescent protein-positive (GFP+) cells, and cultured for various times to monitor establishment of latency, as judged by repression of viral gene expression (RNA/DNA ratio) and loss of virus production. We found that, in the vast majority of cells, latency was established posttranscriptionally in the GFP+infected cells: transcription was initially turned on and then turned off. We also found that some of the GFP−cells were infected, suggesting that latency might be established in these cells at the outset of infection. We were not able to test this hypothesis because some GFP−cells expressed lytic genes and thus it was not possible to separate them from GFP−quiescent cells. In addition, we found that the pattern of expression of lytic genes that have been associated with latency, including UL138, US28, and RNA2.7, was the same as that of other lytic genes, indicating that there was no preferential expression of these genes once latency was established. We confirmed previous studies showing that tumor necrosis factor alpha (TNF-α) induced reactivation of infectious virus, and by analyzing expression of the progenitor cell marker CD34 as well as myeloid cell differentiation markers in IE+cells after treatment with TNF-α, we showed that TNF-α induced transcriptional reactivation of IE gene expression independently of differentiation. TNF-α-mediated reactivation in Kasumi-3 cells was correlated with activation of NF-κB, KAP-1, and ATM.IMPORTANCEHCMV is an important human pathogen that establishes lifelong latent infection in myeloid progenitor cells and reactivates frequently to cause significant disease in immunocompromised people. Our observation that viral gene expression is first turned on and then turned off to establish latency suggests that there is a host defense, which may be myeloid cell specific, responsible for transcriptional silencing of viral gene expression. Our observation that TNF-α induces reactivation independently of differentiation provides insight into molecular mechanisms that control reactivation.

scholarly journals Temporal Dynamics of HCMV Gene Expression in Lytic and Latent Infections

2021 ◽  
Author(s):  
Batsheva Rozman ◽  
Yaarit Kitsberg ◽  
Aharon Nachshon ◽  
Michal Schwartz ◽  
Noam Stern-Ginossar
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Dna Replication ◽  
Latent Infection ◽  
Viral Gene Expression ◽  
Productive Infection ◽  
Viral Gene ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Viral Genes

Primary infection with Human cytomegalovirus (HCMV) results in a persistent lifelong infection due to its ability to establish latent infection. During productive HCMV infection, viral genes are expressed in a coordinated cascade that is characteristic of all herpesviruses and traditionally relies on the dependencies of viral genes on protein synthesis and viral DNA replication. In contrast, the transcriptional landscape associated with HCMV latency is still disputed and poorly understood. Here, we examine viral transcriptomic dynamics during the establishment of both productive and latent HCMV infections. These temporal measurements reveal that viral gene expression dynamics along productive infection and their dependencies on protein synthesis and viral DNA replication, do not fully align. This illustrates that the regulation of herpesvirus genes does not represent a simple sequential transcriptional cascade and surprisingly many viral genes are regulated by multiple independent modules. Using our improved classification of viral gene expression kinetics in conjunction with transcriptome-wide measurements of the effects of a wide array of chromatin modifiers, we unbiasedly show that a defining characteristic of latent cells is the unique repression of immediate early (IE) genes. In particular, we demonstrate that IE1 (a central IE protein) expression is the principal barrier for achieving a full productive cycle. Altogether, our findings provide an unbiased and elaborate definition of HCMV gene expression in lytic and latent infection states.

scholarly journals TNF-α induces reactivation of human cytomegalovirus independently of myeloid cell differentiation following post-transcriptional establishment of latency

2018 ◽  
Author(s):  
Eleonora Forte ◽  
Suchitra Swaminathan ◽  
Mark W. Schroeder ◽  
Jeong Yeon Kim ◽  
Scott S. Terhune ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Differentiation ◽  
Progenitor Cells ◽  
Viral Gene Expression ◽  
Myeloid Cell ◽  
Viral Gene ◽  
Myeloid Progenitor ◽  
Tnf Α ◽  
Myeloid Progenitor Cells ◽  
Lytic Genes

ABSTRACTWe used the Kasumi-3 model to study HCMV latency and reactivation in myeloid progenitor cells. Kasumi-3 cells were infected with HCMV strain TB40/Ewt-GFP, flow sorted for GFP+ cells, and cultured for various times to monitor establishment of latency, as judged by repression of viral gene expression (RNA/DNA ratio) and loss of virus production. We found that, in the vast majority of cells, latency was established post-transcriptionally in the GFP+ infected cells: transcription was initially turned on, and then turned off. We also found that some of the GFP-cells were infected, suggesting that latency might be established in these cells at the outset of infection. We were not able to test this hypothesis because some GFP-cells expressed lytic genes, and thus, it was not possible to separate them from GFP-quiescent cells. In addition, we found that the pattern of expression of lytic genes that have been associated with latency, including UL138, US28, and RNA2.7, was the same as that of other lytic genes, indicating that there was no preferential expression of these genes once latency is established. We confirmed previous studies showing that TNF-α induced reactivation of infectious virus, and by analyzing expression of the progenitor cell marker CD34 as well as myeloid cell differentiation markers in IE+ cells after treatment with TNF-α, we showed that TNF-α induced transcriptional reactivation of IE gene expression independently of differentiation. TNF-α-mediated reactivation in Kasumi-3 cells was correlated with activation of NF-κB, KAP-1 and ATM.IMPORTANCEHCMV is an important human pathogen that establishes lifelong latent infection in myeloid progenitor cells, and reactivates frequently to cause significant disease in immunocompromised people. Our observation that viral gene expression is first turned on, and then turned off to establish latency suggests that there is a host defense, which may be myeloid-specific, responsible for transcriptional silencing of viral gene expression. Our observation that TNF-α induces reactivation independently of differentiation provides insight into molecular mechanisms that control reactivation.

scholarly journals Herpes Simplex Virus Latency Is Noisier the Closer We Look

2019 ◽  
Vol 94 (4) ◽  
Author(s):  
Navneet Singh ◽  
David C. Tscharke
Keyword(s):  
Gene Expression ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Viral Genome ◽  
Infectious Virus ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Peripheral Neurons ◽  
Virus Latency ◽  
Simplex Virus

ABSTRACT During herpes simplex virus (HSV) latency, the viral genome is harbored in peripheral neurons in the absence of infectious virus but with the potential to restart infection. Advances in epigenetics have helped explain how viral gene expression is largely inhibited during latency. Paradoxically, at the same time, the view that latency is entirely silent has been eroding. This low-level noise has implications for our understanding of HSV latency and should not be ignored.

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 Global Analysis of Baculovirus Autographa californica Multiple Nucleopolyhedrovirus Gene Expression in the Midgut of the Lepidopteran HostTrichoplusia ni

2018 ◽  
Vol 92 (23) ◽  
Author(s):  
Anita Shrestha ◽  
Kan Bao ◽  
Yun-Ru Chen ◽  
Wenbo Chen ◽  
Ping Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Line ◽  
Trichoplusia Ni ◽  
Cultured Cells ◽  
Expression Profiles ◽  
Secondary Infection ◽  
Expression Patterns ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Viral Genes

ABSTRACTThe baculovirusAutographa californica multiple nucleopolyhedrovirus(AcMNPV) is a large double-stranded DNA (dsDNA) virus that encodes approximately 156 genes and is highly pathogenic to a variety of larval lepidopteran insects in nature. Oral infection of larval midgut cells is initiated by the occlusion-derived virus (ODV), while secondary infection of other tissues is mediated by the budded virus (BV). Global viral gene expression has been studied in detail in BV-infected cell cultures, but studies of ODV infection in the larval midgut are limited. In this study, we examined expression of the ∼156 AcMNPV genes inTrichoplusia nimidgut tissue using a transcriptomic approach. We analyzed expression profiles of viral genes in the midgut and compared them with profiles from aT. nicell line (Tnms42). Several viral genes (p6.9,orf76,orf75,pp31,Ac-bro,odv-e25, andodv-ec27) had high expression levels in the midgut throughout the infection. Also, the expression of genes associated with occlusion bodies (polhandp10) appeared to be delayed in the midgut in comparison with the cell line. Comparisons of viral gene expression profiles revealed remarkable similarities between the midgut and cell line for most genes, although substantial differences were observed for some viral genes. These included genes associated with high level BV production (fp-25k), acceleration of systemic infection (v-fgf), and enhancement of viral movement (arif-1/orf20). These differential expression patterns appear to represent specific adaptations for virus infection and transmission through the polarized cells of the lepidopteran midgut.IMPORTANCEBaculoviruses such as AcMNPV are pathogens that are natural regulators of certain insect populations. Baculovirus infections are biphasic, with a primary phase initiated by oral infection of midgut epithelial cells by occlusion-derived virus (ODV) virions and a secondary phase in which other tissues are infected by budded-virus (BV) virions. While AcMNPV infections in cultured cells have been studied extensively, comparatively little is known regarding primary infection in the midgut. In these studies, we identified gene expression patterns associated with ODV-mediated infection of the midgut inTrichoplusia niand compared those results with prior results from BV-infected cultured cells, which simulate secondary infection. These studies provide a detailed analysis of viral gene expression patterns in the midgut, which likely represent specific viral strategies to (i) overcome or avoid host defenses in the gut and (ii) rapidly move infection from the midgut, into the hemocoel to facilitate systemic infection.

scholarly journals The Ends Dictate the Means: Promoter Switching in Herpesvirus Gene Expression

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Andrew E. Hale ◽  
Nathaniel J. Moorman
Keyword(s):  
Gene Expression ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Annual Review ◽  
Publication Date ◽  
Alternative Promoters ◽  
Contextual Cues ◽  
Viral Genes ◽  
Functional Consequences ◽  
Post Transcriptional Regulation

Herpesvirus gene expression is dynamic and complex, with distinct complements of viral genes expressed at specific times in different infection contexts. These complex patterns of viral gene expression arise in part from the integration of multiple cellular and viral signals that affect the transcription of viral genes. The use of alternative promoters provides an increased level of control, allowing different promoters to direct the transcription of the same gene in response to distinct temporal and contextual cues. While once considered rare, herpesvirus alternative promoter usage was recently found to be far more pervasive and impactful than previously thought. Here we review several examples of promoter switching in herpesviruses and discuss the functional consequences on the transcriptional and post-transcriptional regulation of viral gene expression. Expected final online publication date for the Annual Review of Virology, Volume 8 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Mechanisms of pathogenesis of emerging adenoviruses

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 90 ◽  
Author(s):  
James Cook ◽  
Jay Radke
Keyword(s):  
Gene Expression ◽  
Human Population ◽  
Viral Gene Expression ◽  
Critical Threshold ◽  
Severe Illness ◽  
Viral Gene ◽  
Altered Expression ◽  
Biological Studies ◽  
Viral Genes

Periodic outbreaks of human adenovirus infections can cause severe illness in people with no known predisposing conditions. The reasons for this increased viral pathogenicity are uncertain. Adenoviruses are constantly undergoing mutation during circulation in the human population, but related phenotypic changes of the viruses are rarely detected because of the infrequency of such outbreaks and the limited biological studies of the emergent strains. Mutations and genetic recombinations have been identified in these new strains. However, the linkage between these genetic changes and increased pathogenicity is poorly understood. It has been observed recently that differences in virus-induced immunopathogenesis can be associated with altered expression of non-mutant viral genes associated with changes in viral modulation of the host innate immune response. Initial small animal studies indicate that these changes in viral gene expression can be associated with enhanced immunopathogenesisin vivo. Available evidence suggests the hypothesis that there is a critical threshold of expression of certain viral genes that determines both the sustainability of viral transmission in the human population and the enhancement of immunopathogenesis. Studies of this possibility will require extension of the analysis of outbreak viral strains from a sequencing-based focus to biological studies of relationships between viral gene expression and pathogenic responses. Advances in this area will require increased coordination among public health organizations, diagnostic microbiology laboratories, and research laboratories to identify, catalog, and systematically study differences between prototype and emergent viral strains that explain the increased pathogenicity that can occur during clinical outbreaks.

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