Human Cytomegalovirus Forms Phase-Separated Compartments at Viral Genomes to Facilitate Viral Replication

2021 ◽  
Author(s):  
Enrico Caragliano ◽  
Stefano Bonazza ◽  
Giada Frascaroli ◽  
Jiajia Tang ◽  
Timothy K. Soh ◽  
...  
Keyword(s):  
Viral Replication ◽  
Human Cytomegalovirus ◽  
Viral Genomes

scholarly journals Reactivation of the Human Cytomegalovirus Major Immediate-Early Regulatory Region and Viral Replication in Embryonal NTera2 Cells: Role of Trichostatin A, Retinoic Acid, and Deletion of the 21-Base-Pair Repeats and Modulator

2001 ◽  
Vol 75 (4) ◽  
pp. 1581-1593 ◽  
Author(s):  
Jeffery L. Meier
Keyword(s):  
Retinoic Acid ◽  
Viral Replication ◽  
Histone Deacetylase ◽  
Human Cytomegalovirus ◽  
Trichostatin A ◽  
Regulatory Region ◽  
Immediate Early ◽  
Unique Region ◽  
Viral Genomes ◽  
Nt2 Cells

ABSTRACT Inactivity of the human cytomegalovirus (HCMV) major immediate-early regulatory region (MIERR), which is composed of promoter, enhancer, unique region, and modulator, is linked to lack of HCMV replication in latently infected cells and in other nonpermissive cell types, including human embryonal NTera2 carcinoma (NT2) cells. I refined the embryonal NT2 cell model to enable characterization of the unknown mechanistic basis for silencing of HCMV MIERR-dependent transcription and viral replication in nonpermissive cells. These infected NT2 cells contain nonreplicating viral genomes with electrophoretic mobility equivalent to a supercoiled, bacterial artificial chromosome of comparable molecular weight. MIERR-dependent transcription is minimal to negligible. Increasing the availability of positive-acting transcription factors by retinoic acid (RA) treatment after infection is largely insufficient in reactivating the MIERR. In contrast, trichostatin A (TSA), a histone deacetylase inhibitor, reactivates MIERR-dependent transcription. Contrary to prior findings produced from transfected MIERR segments, deletion of the 21-bp repeats and modulator from the MIERR in the viral genome does not relieve MIERR silencing. To demonstrate that MIERR silencing likely results from enhancer inactivity, I examined an HCMV with a heterologous MIERR promoter that is enhancer dependent but exempt from IE2 p86-mediated negative autoregulation. This heterologous promoter, like its neighboring native MIERR promoter, exhibits immediate-early transcriptional kinetics in fibroblasts. In embryonal NT2 cells, the heterologous MIERR promoter is transcriptionally inactive. This silence is relieved by TSA but not by RA. Remarkably, TSA-induced reactivation of MIERR-dependent transcription from quiescent viral genomes is followed by release of infectious virus. I conclude that a mechanism of active repression imposes a block to MIERR-dependent transcription and viral replication in embryonal NT2 cells. Because TSA overcomes the block, viral gene silencing may involve histone deacetylase-based modification of viral chromatin, which might account for the covalently closed circular conformation of quiescent HCMV genomes.

scholarly journals Prolonged activation of NF-κB by human cytomegalovirus promotes efficient viral replication and late gene expression

Virology ◽  
2006 ◽  
Vol 346 (1) ◽  
pp. 15-31 ◽  
Author(s):  
Ian B. DeMeritt ◽  
Jagat P. Podduturi ◽  
A. Michael Tilley ◽  
Maciej T. Nogalski ◽  
Andrew D. Yurochko
Keyword(s):  
Gene Expression ◽  
Viral Replication ◽  
Human Cytomegalovirus ◽  
Late Gene ◽  
Late Gene Expression ◽  
Efficient Viral Replication

Viral replication in HeLa/fibroblast hybrid cells infected with human cytomegalovirus

1987 ◽  
Vol 95 (1-2) ◽  
pp. 29-40 ◽  
Author(s):  
Y. Tsutsui ◽  
S. Sonta ◽  
A. Kashiwai ◽  
T. Nogami ◽  
T. Furukawa
Keyword(s):  
Viral Replication ◽  
Human Cytomegalovirus ◽  
Hybrid Cells

scholarly journals A Domain of Herpes Simplex Virus pUL33 Required To Release Monomeric Viral Genomes from Cleaved Concatemeric DNA

2017 ◽  
Vol 91 (20) ◽  
Author(s):  
Kui Yang ◽  
Xiaoqun Dang ◽  
Joel D. Baines
Keyword(s):  
Amino Acids ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Viral Replication ◽  
Dna Cleavage ◽  
Artificial Chromosome ◽  
Viral Dna ◽  
Viral Genomes ◽  
C Terminus ◽  
Simplex Virus

ABSTRACT Monomeric herpesvirus DNA is cleaved from concatemers and inserted into preformed capsids through the actions of the viral terminase. The terminase of herpes simplex virus (HSV) is composed of three subunits encoded by UL15, UL28, and UL33. The UL33-encoded protein (pUL33) interacts with pUL28, but its precise role in the DNA cleavage and packaging reaction is unclear. To investigate the function of pUL33, we generated a panel of recombinant viruses with either deletions or substitutions in the most conserved regions of UL33 using a bacterial artificial chromosome system. Deletion of 11 amino acids (residues 50 to 60 or residues 110 to 120) precluded viral replication, whereas the truncation of the last 10 amino acids from the pUL33 C terminus did not affect viral replication or the interaction of pUL33 with pUL28. Mutations that replaced the lysine at codon 110 and the arginine at codon 111 with alanine codons failed to replicate, and the pUL33 mutant interacted with pUL28 less efficiently. Interestingly, genomic termini of the large (L) and small (S) components were detected readily in cells infected with these mutants, indicating that concatemeric DNA was cleaved efficiently. However, the release of monomeric genomes as assessed by pulsed-field gel electrophoresis was greatly diminished, and DNA-containing capsids were not observed. These results suggest that pUL33 is necessary for one of the two viral DNA cleavage events required to release individual genomes from concatemeric viral DNA. IMPORTANCE This paper shows a role for pUL33 in one of the two DNA cleavage events required to release monomeric genomes from concatemeric viral DNA. This is the first time that such a phenotype has been observed and is the first identification of a function of this protein relevant to DNA packaging other than its interaction with other terminase components.

scholarly journals Two Sp1/Sp3 Binding Sites in the Major Immediate-Early Proximal Enhancer of Human Cytomegalovirus Have a Significant Role in Viral Replication

2005 ◽  
Vol 79 (15) ◽  
pp. 9597-9607 ◽  
Author(s):  
Hiroki Isomura ◽  
Mark F. Stinski ◽  
Ayumi Kudoh ◽  
Tohru Daikoku ◽  
Noriko Shirata ◽  
...  
Keyword(s):  
Viral Replication ◽  
Human Cytomegalovirus ◽  
Significant Role ◽  
Binding Sites ◽  
Human Fibroblast ◽  
Immediate Early ◽  
Fibroblast Cells ◽  
Recombinant Viruses ◽  
Human Fibroblast Cells ◽  
Hcmv Replication

ABSTRACT We previously demonstrated that the major immediate early (MIE) proximal enhancer containing one GC box and the TATA box containing promoter are minimal elements required for transcription and viral replication in human fibroblast cells (H. Isomura, T. Tsurumi, M. F. Stinski, J. Virol. 78:12788-12799, 2004). After infection, the level of Sp1 increased while Sp3 remained constant. Here we report that either Sp1 or Sp3 transcription factors bind to the GC boxes located at approximately positions −55 and −75 relative to the transcription start site (+1). Both the Sp1 and Sp3 binding sites have a positive and synergistic effect on the human cytomegalovirus (HCMV) major immediate-early (MIE) promoter. There was little to no change in MIE transcription or viral replication for recombinant viruses with one or the other Sp1 or Sp3 binding site mutated. In contrast, mutation of both the Sp1 and Sp3 binding sites caused inefficient MIE transcription and viral replication. These data indicate that the Sp1 and Sp3 binding sites have a significant role in HCMV replication in human fibroblast cells.

scholarly journals Bacteriophage self-counting in the presence of viral replication

2021 ◽  
Vol 118 (51) ◽  
pp. e2104163118
Author(s):  
Tianyou Yao ◽  
Seth Coleman ◽  
Thu Vu Phuc Nguyen ◽  
Ido Golding ◽  
Oleg A. Igoshin
Keyword(s):  
Gene Expression ◽  
Viral Replication ◽  
Viral Gene Expression ◽  
Host Cells ◽  
Optimal Decision ◽  
Viral Gene ◽  
Viral Genomes ◽  
Viral Copy Number ◽  
Viral Copy ◽  
Type Phage

When host cells are in low abundance, temperate bacteriophages opt for dormant (lysogenic) infection. Phage lambda implements this strategy by increasing the frequency of lysogeny at higher multiplicity of infection (MOI). However, it remains unclear how the phage reliably counts infecting viral genomes even as their intracellular number increases because of replication. By combining theoretical modeling with single-cell measurements of viral copy number and gene expression, we find that instead of hindering lambda’s decision, replication facilitates it. In a nonreplicating mutant, viral gene expression simply scales with MOI rather than diverging into lytic (virulent) and lysogenic trajectories. A similar pattern is followed during early infection by wild-type phage. However, later in the infection, the modulation of viral replication by the decision genes amplifies the initially modest gene expression differences into divergent trajectories. Replication thus ensures the optimal decision—lysis upon single-phage infection and lysogeny at higher MOI.

scholarly journals Direct infection of CD34+ progenitor cells by human cytomegalovirus: evidence for inhibition of hematopoiesis and viral replication

Blood ◽  
1996 ◽  
Vol 88 (4) ◽  
pp. 1277-1283 ◽  
Author(s):  
M Movassagh ◽  
J Gozlan ◽  
B Senechal ◽  
C Baillou ◽  
JC Petit ◽  
...  
Keyword(s):  
Viral Replication ◽  
Human Cytomegalovirus ◽  
Laboratory Strain ◽  
Inhibitory Effect ◽  
Rt Pcr ◽  
Reverse Transcription Pcr ◽  
Differentiated Cells ◽  
Cd34 Antigen ◽  
Liquid Suspension ◽  
Infected Cells

We successfully infected fluorescence-activated cell-sorted CD34+ cells from normal cord blood by the human cytomegalovirus (HCMV) laboratory strain Towne. An inhibitory effect of HCMV on clonogenic myeloid progenitors was observed in primary methylcellulose cultures. After an initial 7-day liquid culture of CD34(+)-infected cells, this inhibition was further amplified in secondary methylcellulose cultures, then involving both the myeloid and erythroid lineages. Under these conditions, viral DNA was detected both in erythroid and myeloid colonies using the polymerase chain reaction (PCR), but reverse transcription PCR (RT-PCR) failed to detect viral RNA. In contrast, when CD34(+)-infected cells were maintained in liquid suspension, both immediate, early, and late transcripts were detected as soon as day 3. In addition, viral production was demonstrated in the culture supernatants, thus confirming that a complete viral cycle occurred under liquid conditions. Furthermore, by resorting cells into CD34+ and CD34- fractions, we showed by RT-PCR that viral replication took place in cells still expressing CD34 antigen, whereas no RNA was found in more differentiated cells that had subsequently lost their CD34 antigen. These findings suggest that HCMV replication can occur at the early steps of progenitor differentiation and may be involved in the viral-induced myelosuppression.

scholarly journals A cis Element between the TATA Box and the Transcription Start Site of the Major Immediate-Early Promoter of Human Cytomegalovirus Determines Efficiency of Viral Replication

2007 ◽  
Vol 82 (2) ◽  
pp. 849-858 ◽  
Author(s):  
Hiroki Isomura ◽  
Mark F. Stinski ◽  
Ayumi Kudoh ◽  
Sanae Nakayama ◽  
Takayuki Murata ◽  
...  
Keyword(s):  
Viral Replication ◽  
Transcription Start Site ◽  
Gene Transcription ◽  
Human Cytomegalovirus ◽  
Recombinant Virus ◽  
Tata Box ◽  
Immediate Early ◽  
Wild Type Virus ◽  
Start Site ◽  
Transcription Start

ABSTRACT The promoter of the major immediate-early (MIE) genes of human cytomegalovirus (HCMV), also referred to as the CMV promoter, possesses a cis-acting element positioned downstream of the TATA box between positions −14 and −1 relative to the transcription start site (+1). We determined the role of the cis-acting element in viral replication by comparing recombinant viruses with the cis-acting element replaced with other sequences. Recombinant virus with the simian CMV counterpart replicated efficiently in human foreskin fibroblasts, as well as wild-type virus. In contrast, replacement with the murine CMV counterpart caused inefficient MIE gene transcription, RNA splicing, MIE and early viral gene expression, and viral DNA replication. To determine which nucleotides in the cis-acting element are required for efficient MIE gene transcription and splicing, we constructed mutations within the cis-acting element in the context of a recombinant virus. While mutations in the cis-acting element have only a minor effect on in vitro transcription, the effects on viral replication are major. The nucleotides at −10 and −9 in the cis-acting element relative to the transcription start site (+1) affect efficient MIE gene transcription and splicing at early times after infection. The cis-acting element also acts as a cis-repression sequence when the viral IE86 protein accumulates in the infected cell. We demonstrate that the cis-acting element has an essential role in viral replication.

P2Y2 purinergic receptor is induced following human cytomegalovirus infection and its activity is required for efficient viral replication

2016 ◽  
Author(s):  
Saisai Chen ◽  
Thomas Shenk ◽  
Maciej T. Nogalski
Keyword(s):  
Viral Replication ◽  
Host Cell ◽  
Human Cytomegalovirus ◽  
Hcmv Infection ◽  
Purinergic Receptor ◽  
Purinergic Signaling ◽  
Receptor Expression ◽  
Receptor Activity ◽  
P2y2 Receptor ◽  
Infected Cells

AbstractHuman cytomegalovirus (HCMV) manipulates many aspects of host cell biology to create an intracellular milieu optimally supportive of its replication and spread. The current study reveals a role for purinergic signaling in HCMV infection. The levels of several components of the purinergic signaling system, including the P2Y2 receptor, were altered in HCMV-infected fibroblasts. P2Y2 receptor RNA and protein are strongly induced following infection. Pharmacological inhibition of receptor activity or knockdown of receptor expression markedly reduced the production of infectious HCMV progeny. When P2Y2 activity was inhibited, the accumulation of most viral RNAs tested and viral DNA was reduced. In addition, the level of cytosolic calcium within infected cells was reduced when P2Y2 signaling was blocked. The HCMV-coded UL37x1 protein was previously shown to induce calcium flux from the smooth endoplasmic reticulum to the cytosol, and the present study demonstrates that P2Y2 function is required for this mobilization. We conclude that P2Y2 supports the production of HCMV progeny, possibly at multiple points within the viral replication cycle that interface with signaling pathways induced by the purinergic receptor.ImportanceHCMV infection is ubiquitous and can cause life-threatening disease in immunocompromised patients, debilitating birth defects in newborns, and has been increasingly associated with a wide range of chronic conditions. Such broad clinical implications result from the modulation of multiple host cell processes. This study documents that cellular purinergic signaling is usurped in HCMV-infected cells and that the function of this signaling axis is critical for efficient HCMV infection. Therefore, we speculate that blocking P2Y2 receptor activity has the potential to become an attractive novel treatment option for HCMV infection.

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