scholarly journals Herpes Simplex Virus 1 DNA Polymerase RNase H Activity Acts in a 3′-to-5′ Direction and Is Dependent on the 3′-to-5′ Exonuclease Active Site

2017 ◽  
Vol 92 (5) ◽  
Author(s):  
Jessica L. Lawler ◽  
Purba Mukherjee ◽  
Donald M. Coen
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Dna Polymerase ◽  
Polymerase Activity ◽  
Rnase H ◽  
Exonuclease Activity ◽  
Wild Type ◽  
Herpes Simplex Virus 1 ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACTThe catalytic subunit (Pol) of herpes simplex virus 1 (HSV-1) DNA polymerase has been extensively studied both as a model for other family B DNA polymerases and for its differences from these enzymes as an antiviral target. Among the activities of HSV-1 Pol is an intrinsic RNase H activity that cleaves RNA from RNA-DNA hybrids. There has long been a controversy regarding whether this activity is due to the 3′-to-5′ exonuclease of Pol or whether it is a separate activity, possibly acting on 5′ RNA termini. To investigate this issue, we compared wild-type HSV-1 Pol and a 3′-to-5′ exonuclease-deficient mutant, D368A Pol, for DNA polymerase activity, 3′-to-5′ exonuclease activity, and RNase H activityin vitro. Additionally, we assessed the RNase H activity using differentially end-labeled templates with 5′ or 3′ RNA termini. The mutant enzyme was at most modestly impaired for DNA polymerase activity but was drastically impaired for 3′-to-5′ exonuclease activity, with no activity detected even at high enzyme-to-DNA substrate ratios. Importantly, the mutant showed no detectable ability to excise RNA with either a 3′ or 5′ terminus, while the wild-type HSV-1 Pol was able to cleave RNA from the annealed RNA-DNA hairpin template, but only detectably with a 3′ RNA terminus in a 3′-to-5′ direction and at a rate lower than that of the exonuclease activity. These results suggest that HSV-1 Pol does not have an RNase H separable from its 3′-to-5′ exonuclease activity and that this activity prefers DNA degradation over degradation of RNA from RNA-DNA hybrids.IMPORTANCEHerpes simplex virus 1 (HSV-1) is a member of theHerpesviridaefamily of DNA viruses, several of which cause morbidity and mortality in humans. Although the HSV-1 DNA polymerase has been studied for decades and is a crucial target for antivirals against HSV-1 infection, several of its functions remain to be elucidated. A hypothesis suggesting the existence of a 5′-to-3′ RNase H activity intrinsic to this enzyme that could remove RNA primers from Okazaki fragments has been particularly controversial. In this study, we were unable to identify RNase H activity of HSV-1 DNA polymerase on RNA-DNA hybrids with 5′ RNA termini. We detected RNase H activity on hybrids with 3′ termini, but this was due to the 3′-to-5′ exonuclease. Thus, HSV-1 is unlikely to use this method to remove RNA primers during DNA replication but may use pathways similar to those used in eukaryotic Okazaki fragment maturation.

scholarly journals Herpes Simplex Virus 1 UL34 Protein Regulates the Global Architecture of the Endoplasmic Reticulum in Infected Cells

2017 ◽  
Vol 91 (12) ◽  
Author(s):  
Fumio Maeda ◽  
Jun Arii ◽  
Yoshitaka Hirohata ◽  
Yuhei Maruzuru ◽  
Naoto Koyanagi ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Null Mutation ◽  
Wild Type ◽  
Herpes Simplex Virus 1 ◽  
Nuclear Egress ◽  
Infected Cells ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT Upon herpes simplex virus 1 (HSV-1) infection, the CD98 heavy chain (CD98hc) is redistributed around the nuclear membrane (NM), where it promotes viral de-envelopment during the nuclear egress of nucleocapsids. In this study, we attempted to identify the factor(s) involved in CD98hc accumulation and demonstrated the following: (i) the null mutation of HSV-1 UL34 caused specific dispersion throughout the cytoplasm of CD98hc and the HSV-1 de-envelopment regulators, glycoproteins B and H (gB and gH); (ii) as observed with CD98hc, gB, and gH, wild-type HSV-1 infection caused redistribution of the endoplasmic reticulum (ER) markers calnexin and ERp57 around the NM, whereas the UL34-null mutation caused cytoplasmic dispersion of these markers; (iii) the ER markers colocalized efficiently with CD98hc, gB, and gH in the presence and absence of UL34 in HSV-1-infected cells; (iv) at the ultrastructural level, wild-type HSV-1 infection caused ER compression around the NM, whereas the UL34-null mutation caused cytoplasmic dispersion of the ER; and (v) the UL34-null mutation significantly decreased the colocalization efficiency of lamin protein markers of the NM with CD98hc and gB. Collectively, these results indicate that HSV-1 infection causes redistribution of the ER around the NM, with resulting accumulation of ER-associated CD98hc, gB, and gH around the NM and that UL34 is required for ER redistribution, as well as for efficient recruitment to the NM of the ER-associated de-envelopment factors. Our study suggests that HSV-1 induces remodeling of the global ER architecture for recruitment of regulators mediating viral nuclear egress to the NM. IMPORTANCE The ER is an important cellular organelle that exists as a complex network extending throughout the cytoplasm. Although viruses often remodel the ER to facilitate viral replication, information on the effects of herpesvirus infections on ER morphological integrity is limited. Here, we showed that HSV-1 infection led to compression of the global ER architecture around the NM, resulting in accumulation of ER-associated regulators associated with nuclear egress of HSV-1 nucleocapsids. We also identified HSV-1 UL34 as a viral factor that mediated ER remodeling. Furthermore, we demonstrated that UL34 was required for efficient targeting of these regulators to the NM. To our knowledge, this is the first report showing that a herpesvirus remodels ER global architecture. Our study also provides insight into the mechanism by which the regulators for HSV-1 nuclear egress are recruited to the NM, where this viral event occurs.

scholarly journals Herpes Simplex Virus 1 Latency and the Kinetics of Reactivation Are Regulated by a Complex Network of Interactions between the Herpesvirus Entry Mediator, Its Ligands (gD, BTLA, LIGHT, and CD160), and the Latency-Associated Transcript

2018 ◽  
Vol 92 (24) ◽  
Author(s):  
Shaohui Wang ◽  
Alexander V. Ljubimov ◽  
Ling Jin ◽  
Klaus Pfeffer ◽  
Mitchell Kronenberg ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Trigeminal Ganglia ◽  
Wild Type ◽  
Herpes Simplex Virus 1 ◽  
Latently Infected ◽  
Simplex Virus ◽  
Kinetics Of ◽  
Herpesvirus Entry Mediator ◽  
Hsv 1

ABSTRACTRecently, we reported that the herpesvirus entry mediator (HVEM; also called TNFRSF14 or CD270) is upregulated by the latency-associated transcript (LAT) of herpes simplex virus 1 (HSV-1) and that the absence of HVEM affects latency reactivation but not primary infection in ocularly infected mice. gD has been shown to bind to HVEM. LIGHT (TNFSF14), CD160, and BTLA (B- and T-lymphocyte attenuator) also interact with HVEM and can interfere with HSV gD binding. It was not known if LIGHT, CD160, or BTLA affected the level of latency reactivation in the trigeminal ganglia (TG) of latently infected mice. To address this issue, we ocularly infected LIGHT−/−, CD160−/−, and BTLA−/−mice with LAT(+) and LAT(−) viruses, using similarly infected wild-type (WT) and HVEM−/−mice as controls. The amount of latency, as determined by the levels of gB DNA in the TG of the LIGHT−/−, CD160−/−, and BTLA−/−mice infected with either LAT(+) or LAT(−) viruses, was lower than that in WT mice infected with LAT(+) virus and was similar in WT mice infected with LAT(−) virus. The levels of LAT RNA in HVEM−/−, LIGHT−/−, CD160−/−, and BTLA−/−mice infected with LAT(+) virus were similar and were lower than the levels of LAT RNA in WT mice. However, LIGHT−/−, CD160−/−, and BTLA−/−mice, independent of the presence of LAT, had levels of reactivation similar to those of WT mice infected with LAT(+) virus. Faster reactivation correlated with the upregulation of HVEM transcript. The LIGHT−/−, CD160−/−, and BTLA−/−mice had higher levels of HVEM expression, and this, along with the absence of BTLA, LIGHT, or CD160, may contribute to faster reactivation, while the absence of each molecule, independent of LAT, may have contributed to lower latency. This study suggests that, in the absence of competition with gD for binding to HVEM, LAT RNA is important for WT levels of latency but not for WT levels of reactivation.IMPORTANCEThe effects of BTLA, LIGHT, and CD160 on latency reactivation are not known. We show here that in BTLA, LIGHT, or CD160 null mice, latency is reduced; however, HVEM expression is upregulated compared to that of WT mice, and this upregulation is associated with higher reactivation that is independent of LAT but dependent on gD expression. Thus, one of the mechanisms by which BTLA, LIGHT, and CD160 null mice enhance reactivation appears to be the increased expression of HVEM in the presence of gD. Thus, our results suggest that blockade of HVEM-LIGHT-BTLA-CD160 contributes to reduced HSV-1 latency and reactivation.

scholarly journals Contrasting Effects of W781V and W780V Mutations in Helix N of Herpes Simplex Virus 1 and Human Cytomegalovirus DNA Polymerases on Antiviral Drug Susceptibility

2015 ◽  
Vol 89 (8) ◽  
pp. 4636-4644 ◽  
Author(s):  
Jocelyne Piret ◽  
Nathalie Goyette ◽  
Brian E. Eckenroth ◽  
Emilien Drouot ◽  
Matthias Götte ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Antiviral Drug ◽  
Drug Susceptibility ◽  
Herpes Simplex Virus 1 ◽  
Simplex Virus ◽  
Antiviral Drug Susceptibility ◽  
Hsv 1

ABSTRACTDNA polymerases of theHerpesviridaeand bacteriophage RB69 belong to the α-like DNA polymerase family. In spite of similarities in structure and function, the RB69 enzyme is relatively resistant to foscarnet, requiring the mutation V478W in helix N to promote the closed conformation of the enzyme to make it susceptible to the antiviral. Here, we generated recombinant herpes simplex virus 1 (HSV-1) and human cytomegalovirus (HCMV) mutants harboring the revertant in UL30 (W781V) and UL54 (W780V) DNA polymerases, respectively, to further investigate the impact of this tryptophan on antiviral drug susceptibility and viral replicative capacity. The mutation W781V in HSV-1 induced resistance to foscarnet, acyclovir, and ganciclovir (3-, 14-, and 3-fold increases in the 50% effective concentrations [EC50s], respectively). The recombinant HCMV mutant harboring the W780V mutation was slightly resistant to foscarnet (a 1.9-fold increase in the EC50) and susceptible to ganciclovir. Recombinant HSV-1 and HCMV mutants had altered viral replication kinetics. The apparent inhibition constant values of foscarnet against mutant UL30 and UL54 DNA polymerases were 45- and 4.9-fold higher, respectively, than those against their wild-type counterparts. Structural evaluation of the tryptophan position in the UL54 DNA polymerase suggests that the bulkier phenylalanine (fingers domain) and isoleucine (N-terminal domain) could induce a tendency toward the closed conformation greater than that for UL30 and explains the modest effect of the W780V mutation on foscarnet susceptibility. Our results further suggest a role of the tryptophan in helix N in conferring HCMV and especially HSV-1 susceptibility to foscarnet and the possible contribution of other residues localized at the interface between the fingers and N-terminal domains.IMPORTANCEDNA polymerases of theHerpesviridaeand bacteriophage RB69 belong to the α-like DNA polymerase family. However, the RB69 DNA polymerase is relatively resistant to the broad-spectrum antiviral agent foscarnet. The mutation V478W in helix N of the fingers domain caused the enzyme to adopt a closed conformation and to become susceptible to the antiviral. We generated recombinant herpes simplex virus 1 (HSV-1) and human cytomegalovirus (HCMV) mutants harboring the revertant in UL30 (W781V) and UL54 (W780V) DNA polymerases, respectively, to further investigate the impact of this tryptophan on antiviral drug susceptibility. The W781V mutation in HSV-1 induced resistance to foscarnet, whereas the W780V mutation in HCMV slightly decreased drug susceptibility. This study suggests that the different profiles of susceptibility to foscarnet of the HSV-1 and HCMV mutants could be related to subtle conformational changes resulting from the interaction between residues specific to each enzyme that are located at the interface between the fingers and the N-terminal domains.

scholarly journals Phosphorylation of Herpes Simplex Virus 1 dUTPase Upregulated Viral dUTPase Activity To Compensate for Low Cellular dUTPase Activity for Efficient Viral Replication

2014 ◽  
Vol 88 (14) ◽  
pp. 7776-7785 ◽  
Author(s):  
Akihisa Kato ◽  
Yoshitaka Hirohata ◽  
Jun Arii ◽  
Yasushi Kawaguchi
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Viral Replication ◽  
Enzymatic Activity ◽  
Wild Type ◽  
Herpes Simplex Virus 1 ◽  
Wild Type Level ◽  
Simplex Virus ◽  
Efficient Viral Replication ◽  
Hsv 1

ABSTRACTWe recently reported that herpes simplex virus 1 (HSV-1) protein kinase Us3 phosphorylated viral dUTPase (vdUTPase) at serine 187 (Ser-187) to upregulate its enzymatic activity, which promoted HSV-1 replication in human neuroblastoma SK-N-SH cells but not in human carcinoma HEp-2 cells. In the present study, we showed that endogenous cellular dUTPase activity in SK-N-SH cells was significantly lower than that in HEp-2 cells and that overexpression of cellular dUTPase in SK-N-SH cells increased the replication of an HSV-1 mutant with an alanine substitution for Ser-187 (S187A) in vdUTPase to the wild-type level. In addition, we showed that knockdown of cellular dUTPase in HEp-2 cells significantly reduced replication of the mutant vdUTPase (S187A) virus but not that of wild-type HSV-1. Furthermore, the replacement of Ser-187 in vdUTPase with aspartic acid, which mimics constitutive phosphorylation, and overexpression of cellular dUTPase restored viral replication to the wild-type level in cellular dUTPase knockdown HEp-2 cells. These results indicated that sufficient dUTPase activity was required for efficient HSV-1 replication and supported the hypothesis that Us3 phosphorylation of vdUTPase Ser-187 upregulated vdUTPase activity in host cells with low cellular dUTPase activity to produce efficient viral replication.virus.IMPORTANCEIt has long been assumed that dUTPase activity is important for replication of viruses encoding a dUTPase and that the viral dUTPase (vdUTPase) activity was needed if host cell dUTPase activity was not sufficient for efficient viral replication. In the present study, we showed that the S187A mutation in HSV-1 vdUTPase, which impaired its enzymatic activity, reduced viral replication in SK-N-SH cells, which have low endogenous cellular dUTPase activity, and that overexpression of cellular dUTPase restored viral replication to the wild-type level. We also showed that knockdown of cellular dUTPase in HEp-2 cells, which have higher dUTPase activity than do SK-N-SH cells, reduced replication of HSV-1 with the vdUTPase mutation but had no effect on wild-type virus replication. This is the first report, to our knowledge, directly showing that dUTPase activity is critical for efficient viral replication and that vdUTPase compensates for low host cell dUTPase activity to produce efficient viral replication.

scholarly journals Sequence Analysis of Herpes Simplex Virus 1 Thymidine Kinase and DNA Polymerase Genes from over 300 Clinical Isolates from 1973 to 2014 Finds Novel Mutations That May Be Relevant for Development of Antiviral Resistance

2015 ◽  
Vol 59 (8) ◽  
pp. 4938-4945 ◽  
Author(s):  
Susanne Schmidt ◽  
Kathrin Bohn-Wippert ◽  
Peter Schlattmann ◽  
Roland Zell ◽  
Andreas Sauerbrei
Keyword(s):  
Herpes Simplex Virus ◽  
Amino Acid ◽  
Herpes Simplex ◽  
Thymidine Kinase ◽  
Dna Polymerase ◽  
Herpes Simplex Virus 1 ◽  
Immunosuppressed Patients ◽  
Resistant Strains ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACTA total of 302 clinical herpes simplex virus 1 (HSV-1) strains, collected over 4 decades from 1973 to 2014, were characterized retrospectively for drug resistance. All HSV-1 isolates were analyzed genotypically for nonsynonymous mutations in the thymidine kinase (TK) and DNA polymerase (Pol) genes. The resistance phenotype against acyclovir (ACV) and/or foscarnet (FOS) was examined in the case of novel, unclear, or resistance-related mutations. Twenty-six novel natural polymorphisms could be detected in the TK gene and 69 in the DNA Pol gene. Furthermore, three novel resistance-associated mutations (two in the TK gene and one in the DNA Pol gene) were analyzed, and eight known but hitherto unclear amino acid substitutions (two encoded in TK and six in the DNA Pol gene) could be clarified. Between 1973 and 2014, the distribution of amino acid changes related to the natural gene polymorphisms of TK and DNA Pol remained largely stable. Resistance to ACV was confirmed phenotypically for 16 isolates, and resistance to ACV plus FOS was confirmed for 1 isolate. Acyclovir-resistant strains were observed from the year 1995 onwards, predominantly in immunosuppressed patients, especially those with stem cell transplantation, and the number of ACV-resistant strains increased during the last 2 decades. The data confirm the strong genetic variability among HIV-1 isolates, which is more pronounced in the DNA Pol gene than in the TK gene, and will facilitate considerably the rapid genotypic diagnosis of HSV-1 resistance.

scholarly journals Complete Genome Sequence of Herpes Simplex Virus 1 Strain McKrae

2019 ◽  
Vol 8 (39) ◽  
Author(s):  
Xiaoli Jiao ◽  
Hongyan Sui ◽  
Christopher Lyons ◽  
Bao Tran ◽  
Brad T. Sherman ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Single Molecule ◽  
Complete Sequence ◽  
Wild Type ◽  
Genetic Determinants ◽  
Herpes Simplex Virus 1 ◽  
Simplex Virus ◽  
Highly Virulent ◽  
Hsv 1

Herpes simplex virus 1 (HSV-1) strain McKrae is highly virulent and relatively neuroinvasive in animal models compared with other wild-type HSV-1 strains. To identify the genetic determinants that lead to the unique phenotypes of the McKrae strain, we sequenced its genome with PacBio single-molecule real-time (SMRT) technology and resolved the complete sequence.

scholarly journals Roles of conserved residues within the pre-NH2-terminal domain of herpes simplex virus 1 DNA polymerase in replication and latency in mice

2014 ◽  
Vol 95 (4) ◽  
pp. 940-947 ◽  
Author(s):  
Shariya L. Terrell ◽  
Jean M. Pesola ◽  
Donald M. Coen
Keyword(s):  
Cell Culture ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Dna Synthesis ◽  
Dna Polymerase ◽  
Infectious Virus ◽  
Viral Dna ◽  
Herpes Simplex Virus 1 ◽  
Simplex Virus ◽  
Hsv 1

The catalytic subunit of the herpes simplex virus 1 DNA polymerase (HSV-1 Pol) is essential for viral DNA synthesis and production of infectious virus in cell culture. While mutations that affect 5′–3′ polymerase activity have been evaluated in animal models of HSV-1 infection, mutations that affect other functions of HSV-1 Pol have not. In a previous report, we utilized bacterial artificial chromosome technology to generate defined HSV-1 pol mutants with lesions in the previously uncharacterized pre-NH2-terminal domain. We found that the extreme N-terminal 42 residues (deletion mutant polΔN43) were dispensable for replication in cell culture, while residues 44–49 (alanine-substitution mutant polA6) were required for efficient viral DNA synthesis and production of infectious virus. In this study, we sought to address the importance of these conserved elements in viral replication in a mouse corneal infection model. Mutant virus polΔN43 exhibited no meaningful defect in acute or latent infection despite strong conservation of residues 1–42 with HSV-2 Pol. The polA6 mutation caused a modest defect in replication at the site of inoculation, and was severely impaired for ganglionic replication, even at high inocula that permitted efficient corneal replication. Additionally, the polA6 mutation resulted in reduced latency establishment and subsequent reactivation. Moreover, we found that the polA6 replication defect in cultured cells was exacerbated in resting cells as compared to dividing cells. These results reveal an important role for the conserved motif at residues 44–49 of HSV-1 Pol for ganglionic viral replication.

scholarly journals State and Role of Src Family Kinases in Replication of Herpes Simplex Virus 1

2006 ◽  
Vol 80 (7) ◽  
pp. 3349-3359 ◽  
Author(s):  
Yu Liang ◽  
Bernard Roizman
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Mutant Cell ◽  
Src Kinase ◽  
Src Family Kinases ◽  
Wild Type ◽  
Herpes Simplex Virus 1 ◽  
Kinase Family ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT An earlier report showed that infected cell protein no. 0 (ICP0) of herpes simplex virus 1 (HSV-1) interacts with the SH3 domains of a recently discovered adaptor protein, CIN85. Here, we report the following. (i) ICP0 also interacts with other SH3 domain-containing proteins and, in particular, with nonneuronal members of the Src kinase family. (ii) HSV-1 infection enhanced the activating phosphorylation of Tyr416 of the members of the Src kinase family, modestly enhanced the kinase activity of Src, and posttranslationally modified at least one additional member of the Src kinase family by phosphorylation in a manner dependent on the viral gene products ICP0, unique short 3 (US3), and unique long 13 (UL13). (iii) To define the roles of Src kinase family members, we examined the accumulation of viral proteins, DNA, and mRNA and virus yields from wild-type mouse embryo fibroblasts and sibling cells lacking Src, Fyn, and Yes (SYF−); a mutant cell line, +Src, in which Src was restored to SYF− cells; and the mutant cell line (CSK−) lacking the negative regulator Csk gene of the Src kinase family. Representative α, β, and γ2 proteins accumulated in the largest amounts in SYF− cells and the smallest amounts in +Src compared to wild-type cells. The CSK− cells yielded smaller amounts of the γ2 protein and at least 10-fold less virus than wild-type cells. We conclude that HSV-1 proteins regulate the activities of Src family kinases to achieve optimal viral yields in the course of viral replication.

scholarly journals HCFC1R1 Deficiency Blocks Herpes Simplex Virus-1 Infection by Inhibiting Nuclear Translocation of HCFC1 and VP16

2020 ◽  
Author(s):  
Yangkun Shen ◽  
Zhoujie Ye ◽  
Xiangqian Zhao ◽  
Zhihua Feng ◽  
Jinfeng Chen ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Host Cell ◽  
Host Cells ◽  
The Novel ◽  
Wild Type ◽  
Herpes Simplex Virus 1 ◽  
Novel Target ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACTUpon HSV-1 infection, viral protein 16 (VP16), supported by Host Cell Factor C1 (HCFC1), is rapidly transported into the nucleus, and help to express a series of HSV-1 immediate-early proteins to begin its lytic replication. However, no direct evidence has shown if the HCFC1 deficiency can affect the proliferation of HSV-1 so far. Here, we showed that the HCFC1 deficiency led to a strong resistance to HSV-1 infection. Moreover, we identified Host Cell Factor C1 Regulator 1 (HCFC1R1) as a new host factor acting early in HSV infection for the transport of the HSV-1 capsid to the nucleus. The HCFC1R1 deficiency also led to a strong resistance to HSV-1 infection. The HCFC1R1 deficiency did not affect the attachment of HSV-1 to host cells but act early in HSV-1 infection by perturbing the formation of HCFC1/VP16 complex. Remarkably, in addition to wild-type HSV-1 infection, the host cells in the absence of either HCFC1 or HCFC1R1 showed strong resistant to the infection of TK-deficient HSV-1, which strain can course severe symptoms and tolerate to the current anti-HSV drug Acyclovir. Our data suggest that HCFC1 or HCFC1R1 may be used as the novel target for developing anti-HSV-1 therapies.IMPORTANCEHerpes simplex virus-1 (HSV-1) is widely spread in the human population and can cause a variety of herpetic diseases. Acyclovir, a guanosine analogue that targets the TK protein of HSV-1, is the first specific and selective anti-HSV-1 drug. However, the rapid emergence of resistant HSV-1 strains is occurring worldwide, endangering the efficacy of Acyclovir. Alternatively, targeting host factors is another strategy to stop HSV-1 infection. Unfortunately, although the HSV-1’s receptor, Nectin-1, was discovered in 1998, no effective antiviral drug to date has been developed by targeting Nectin-1. Targeting multiple pathways is the ultimate choice to prevent HSV-1 infection. Here we demonstrated that the deletion of HCFC1 or HCFC1R1 exhibits a strong inhibitory effect on both wild-type and TK-deficient HSV-1. Overall, we present evidence that HCFC1 or HCFC1R1 may be used as the novel target for developing anti-HSV-1 therapies with a defined mechanism of action.

scholarly journals Protein Kinase B/Akt Is Present in Activated Form throughout the Entire Replicative Cycle of ΔUS3 Mutant Virus but Only at Early Times after Infection with Wild-Type Herpes Simplex Virus 1

2006 ◽  
Vol 80 (7) ◽  
pp. 3341-3348 ◽  
Author(s):  
Luca Benetti ◽  
Bernard Roizman
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Protein Kinase ◽  
Protein Kinase B ◽  
Mutant Virus ◽  
Wild Type ◽  
Herpes Simplex Virus 1 ◽  
Infected Cells ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT The product of the herpes simplex virus 1 (HSV-1) US3 gene is a multifunctional serine-threonine protein kinase that can block apoptosis induced by proapoptotic cellular proteins, exogenous agents, or replication-defective viruses. Earlier studies showed that the US3 kinase activates and functionally overlaps cellular protein kinase A (PKA). In this study we examined the status of phosphatidylinositol 3-kinase [PI(3)K] and of its effector, protein kinase B/Akt (PKB/Akt), a component of a major pathway of mammalian antiapoptotic signaling systems. We report the following. (i) Infection of target cells with HSV-1 induces transient phosphorylation of serine 473 of PKB/Akt early in infection, with a mechanism that is dependent on PI(3)K. Inhibition of PI(3)K induced apoptosis in mock-infected or ΔUS3 mutant-virus-infected but not in wild-type-virus-infected cells and reduced the accumulation of specific viral gene products, including the US3 protein kinase, but had a marginal effect on virus yields. (ii) At later times after infection, the total amounts of PKB/Akt decreased and phosphorylated PKB/Akt forms disappeared in a US3-dependent and protein phosphatase 2A-independent manner. (iii) Activation of PKA by forskolin did not mediate significant dephosphorylation of PKB/Akt. Our results are consistent with the model that PKB/Akt is activated early in infection and acts to block apoptosis in infected cells prior to the accumulation of US3 protein kinase and that it persists and continues to function as an antiapoptotic protein in the absence of US3 but becomes redundant or even inimical once US3 protein kinase accumulates in effective amounts.

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