scholarly journals Processing of α-Globin and ICP0 mRNA in Cells Infected with Herpes Simplex Virus Type 1 ICP27 Mutants

2000 ◽  
Vol 74 (16) ◽  
pp. 7307-7319 ◽  
Author(s):  
Kimberly S. Ellison ◽  
Stephen A. Rice ◽  
Robert Verity ◽  
James R. Smiley

ABSTRACT Herpes simplex virus (HSV) ICP27 is an essential and multifunctional regulator of viral gene expression that modulates RNA splicing, polyadenylation, and nuclear export. We have previously reported that ICP27 causes the cytoplasmic accumulation of unspliced α-globin pre-mRNA. Here we examined the effects of a series of ICP27 mutations that alter important functional regions of the protein on the processing and nuclear transport of α-globin and HSV ICP0 RNA. The results demonstrate that ICP27 mutants that are impaired for growth in noncomplementing cells, including mutants in the N- and C-terminal regions, are defective in the accumulation of α-globin pre-mRNA. Unexpectedly, several mutants that are competent to repress the expression of reporter genes in transient transfection assays failed to accumulate unspliced RNA, implying that different mechanisms are responsible for transrepression and pre-mRNA accumulation. Several mutants caused a marked increase in the length and heterogeneity of the α-globin mRNA poly(A) tail, suggesting that ICP27 may directly or indirectly affect the regulation of poly(A) polymerase. ICP27 was also required for the accumulation of multiple ICP0 intron-bearing transcripts, but this effect displayed a mutational sensitivity profile different from that of accumulation of unspliced α-globin RNA. Moreover, unlike spliced and unspliced α-globin RNAs, which were efficiently exported to the cytoplasm, spliced and intron-containing ICP0 transcripts were predominantly nuclear in localization, and ICP27 was not required for nuclear retention of the spliced message. We propose that these transcript- and ICP27 allele-specific differences may be explained by the presence of a strong cis-acting ICP27 response element in the α-globin transcript.

2014 ◽  
Vol 112 (1) ◽  
pp. E49-E55 ◽  
Author(s):  
Te Du ◽  
Zhiyuan Han ◽  
Guoying Zhou ◽  
Bernard Roizman

The key events in herpes simplex virus (HSV) infections are (i) replication at a portal of entry into the body modeled by infection of cultured cells; (ii) establishment of a latent state characterized by a sole latency-associated transcript and microRNAs (miRNAs) modeled in murine peripheral ganglia 30 d after inoculation; and (iii) reactivation from the latent state modeled by excision and incubation of ganglia in medium containing anti-NGF antibody for a timespan of a single viral replicative cycle. In this report, we examine the pattern of synthesis and accumulation of 18 HSV-1 miRNAs in the three models. We report the following: (i) H2-3P, H3-3P, H4-3P, H5-3P, H6-3P, and H7-5P accumulated in ganglia harboring latent virus. All but H4-3P were readily detected in productively infected cells, and most likely they originate from three transcriptional units. (ii) H8-5P, H15, H17, H18, H26, and H27 accumulated during reactivation. Of this group, only H26 and H27 could be detected in productively infected cells. (iii) Of the 18 we have examined, only 10 miRNAs were found to accumulate above background levels in productively infected cells. The disparity in the accumulation of miRNAs in cell culture and during reactivation may reflect differences in the patterns of regulation of viral gene expression during productive infection and during reactivation from the latent state.


2005 ◽  
Vol 79 (13) ◽  
pp. 8348-8360 ◽  
Author(s):  
Danna Hargett ◽  
Tim McLean ◽  
Steven L. Bachenheimer

ABSTRACT We previously reported that herpes simplex virus type 1 (HSV-1) can activate the stress-activated protein kinases (SAPKs) p38 and JNK. In the present study, we undertook a comprehensive and comparative analysis of the requirements for viral protein synthesis in the activation of JNK and p38. Infection with the UL36 mutant tsB7 or with UV-irradiated virus indicated that both JNK and p38 activation required viral gene expression. Cycloheximide reversal or phosphonoacetic acid treatment of wild-type virus-infected cells as well as infection with the ICP4 mutant vi13 indicated that only the immediate-early class of viral proteins were required for SAPK activation. Infection with ICP4, ICP27, or ICP0 mutant viruses indicated that only ICP27 was necessary. Additionally, we determined that in the context of virus infection ICP27 was sufficient for SAPK activation and activation of the p38 targets Mnk1 and MK2 by infecting with mutants deleted for various combinations of immediate-early proteins. Specifically, the d100 (0−/4−) and d103 (4−/22−/47−) mutants activated p38 and JNK, while the d106 (4−/22−/27−/47−) and d107 (4−/27−) mutants did not. Finally, infections with a series of ICP27 mutants demonstrated that the functional domain of ICP27 required for activation was located in the region encompassing amino acids 20 to 65 near the N terminus of the protein and that the C-terminal transactivation activity of ICP27 was not necessary.


2019 ◽  
Vol 94 (4) ◽  
Author(s):  
Navneet Singh ◽  
David C. Tscharke

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.


mBio ◽  
2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Jesse H. Arbuckle ◽  
Thomas M. Kristie

ABSTRACTUpon infection, the genome of herpes simplex virus is rapidly incorporated into nucleosomes displaying histone modifications characteristic of heterochromatic structures. The initiation of infection requires complex viral-cellular interactions that ultimately circumvent this repression by utilizing host cell enzymes to remove repressive histone marks and install those that promote viral gene expression. The reversion of repression and activation of viral gene expression is mediated by the cellular coactivator HCF-1 in association with histone demethylases and methyltransferases. However, the mechanisms and the components that are involved in the initial repression remain unclear. In this study, the chromatin remodeler chromodomain helicase DNA binding (CHD3) protein is identified as an important component of the initial repression of the herpesvirus genome. CHD3 localizes to early viral foci and suppresses viral gene expression. Depletion of CHD3 results in enhanced viral immediate early gene expression and an increase in the number of transcriptionally active viral genomes in the cell. Importantly, CHD3 can recognize the repressive histone marks that have been detected in the chromatin associated with the viral genome and this remodeler is important for ultimately reducing the levels of accessible viral genomes. A model is presented in which CHD3 represses viral infection in opposition to the actions of the HCF-1 coactivator complex. This dynamic, at least in part, determines the initiation of viral infection.IMPORTANCEChromatin modulation of herpesvirus infection is a dynamic process involving regulatory components that mediate suppression and those that promote viral gene expression and the progression of infection. The mechanisms by which the host cell employs the assembly and modulation of chromatin as an antiviral defense strategy against an invading herpesvirus remain unclear. This study defines a critical cellular component that mediates the initial repression of infecting HSV genomes and contributes to understanding the dynamics of this complex interplay between host cell and viral pathogen.


Virology ◽  
2016 ◽  
Vol 495 ◽  
pp. 148-160 ◽  
Author(s):  
Carolina Sanabria-Solano ◽  
Carmen Elena Gonzalez ◽  
Nicolas Richerioux ◽  
Luc Bertrand ◽  
Slimane Dridi ◽  
...  

2012 ◽  
Vol 87 (3) ◽  
pp. 1443-1453 ◽  
Author(s):  
Martha Stefanidou ◽  
Irene Ramos ◽  
Veronica Mas Casullo ◽  
Janie B. Trépanier ◽  
Sara Rosenbaum ◽  
...  

ABSTRACTHerpes simplex virus 2 (HSV-2) may cause frequent recurrences, highlighting its ability to evade host defense. This study tested the hypothesis that HSV-2 interferes with dendritic cell (DC) function as an escape mechanism, which may contribute to enhanced HIV replication in coinfected populations. Immature monocyte-derived human DCs were exposed to live or UV-inactivated HSV-2 or lipopolysaccharide. Little or no increase in the maturation marker CD83 was observed in response to HSV-2 and HSV-2 exposed DCs were impaired in their ability to present antigen (influenza) to T cells. Exposure to UV-inactivated virus stimulated a modest, but significant increase in CD83, suggesting that viral gene expression contributes to the block in DC maturation. The functional impairment of HSV-2-exposed DCs could be partially attributed to the induction of apoptosis. Live and inactivated HSV-2 triggered an increase in the number of early and late apoptotic cells in both the infected and bystander cell populations; apoptosis was associated with a decrease in cellular FLICE-inhibitory protein (c-FLIP). Paradoxically, HSV-2 induced Akt phosphorylation, which typically promotes DC maturation and survival. Despite these aberrant responses, live and inactivated HSV-2 induced the release of cytokines into culture supernatants, which were sufficient to activate HIV-1 replication in latently infected U1 cells. Together, these findings suggest that in the presence of overt or subclinical HSV-2, the function of mucosal DCs would be impaired. These responses may allow HSV to escape immune surveillance but may also promote HIV infection and contribute to the epidemiological link between HIV and HSV.


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