scholarly journals Herpes Simplex Virus Type 1 Primary Envelopment: UL34 Protein Modification and the US3-UL34 Catalytic Relationship

2004 ◽  
Vol 78 (1) ◽  
pp. 399-412 ◽  
Author(s):  
Brent J. Ryckman ◽  
Richard J. Roller

ABSTRACT The herpes simplex virus type 1 (HSV-1) US3 kinase is likely important for primary envelopment of progeny nucleocapsids since it localizes to the nuclear envelope of infected cells and largely determines the phosphorylation state and localization of the necessary primary envelopment factor, the UL34 protein. In HEp-2 cells, the production of infectious US3 null progeny is delayed and decreased relative to that of the parental strain, HSV-1(F). Furthermore, the US3 kinase affects the morphology of primary envelopment such that in its absence, UL34 protein-containing enveloped virions accumulate within membrane-bound vesicles. These vesicles are most often found along the interior periphery of the nucleus and may be derived from the inner nuclear membrane. Since the US3 and UL34 proteins comprise a kinase-substrate pair, a reasonable hypothesis is that the US3 kinase influences these replication parameters by direct phosphorylation of the UL34 protein. For this report, recombinant viruses were constructed to determine the significance of UL34 protein phosphorylation and US3 catalytic activity on UL34 protein localization, single-step growth, and envelopment morphology in both HEp-2 and Vero cells. The data presented suggest that the significance of UL34 phosphorylation is cell type dependent and that efficient viral morphogenesis requires US3-mediated phosphorylation of an infected cell protein other than UL34.

2006 ◽  
Vol 80 (21) ◽  
pp. 10565-10578 ◽  
Author(s):  
Danna Hargett ◽  
Stephen Rice ◽  
Steven L. Bachenheimer

ABSTRACT The ability of herpes simplex virus type 1 (HSV-1) to activate NF-κB has been well documented. Beginning at 3 to 5 h postinfection, HSV-1 induces a robust and persistent nuclear translocation of an NF-κB-dependent (p50/p65 heterodimer) DNA binding activity, as measured by electrophoretic mobility shift assay. Activation requires virus binding and entry, as well as de novo infected-cell protein synthesis, and is accompanied by loss of both IκBα and IκBβ. In this study, we identified loss of IκBα as a marker of NF-κB activation, and infection with mutants with individual immediate-early (IE) regulatory proteins deleted indicated that ICP27 was necessary for IκBα loss. Analysis of both N-terminal and C-terminal mutants of ICP27 identified the region from amino acids 21 to 63 as being necessary for IκBα loss. Additional experiments with mutant viruses with combinations of IE genes deleted revealed that the ICP27-dependent mechanism of NF-κB activation may be augmented by functional ICP4. We also analyzed two additional markers for NF-κB activation, phosphorylation of the p65 subunit on Ser276 and Ser536. Phosphorylation of both serines was induced upon HSV infection and required functional ICP4 and ICP27. Pharmacological inhibitor studies revealed that both IκBα and Ser276 phosphorylation were dependent on Jun N-terminal protein kinase activity, while Ser536 phosphorylation was not affected during inhibitor treatment. These results demonstrate that there are several layers of regulation of NF-κB activation during HSV infection, highlighting the important role that NF-κB may play in infection.


2002 ◽  
Vol 76 (18) ◽  
pp. 9232-9241 ◽  
Author(s):  
John M. Lubinski ◽  
Ming Jiang ◽  
Lauren Hook ◽  
Yueh Chang ◽  
Chad Sarver ◽  
...  

ABSTRACT Herpes simplex virus type 1 (HSV-1) encodes a complement-interacting glycoprotein, gC, and an immunoglobulin G (IgG) Fc binding glycoprotein, gE, that mediate immune evasion by affecting multiple aspects of innate and acquired immunity, including interfering with complement components C1q, C3, C5, and properdin and blocking antibody-dependent cellular cytotoxicity. Previous studies evaluated the individual contributions of gC and gE to immune evasion. Experiments in a murine model that examines the combined effects of gC and gE immune evasion on pathogenesis are now reported. Virulence of wild-type HSV-1 is compared with mutant viruses defective in gC-mediated C3 binding, gE-mediated IgG Fc binding, or both immune evasion activities. Eliminating both activities greatly increased susceptibility of HSV-1 to antibody and complement neutralization in vitro and markedly reduced virulence in vivo as measured by disease scores, virus titers, and mortality. Studies with C3 knockout mice indicated that other activities attributed to these glycoproteins, such as gC-mediated virus attachment to heparan sulfate or gE-mediated cell-to-cell spread, do not account for the reduced virulence of mutant viruses. The results support the importance of gC and gE immune evasion in vivo and suggest potential new targets for prevention and treatment of HSV disease.


2004 ◽  
Vol 78 (9) ◽  
pp. 4599-4608 ◽  
Author(s):  
Nina Bacher Reuven ◽  
Susumu Antoku ◽  
Sandra K. Weller

ABSTRACT The herpes simplex virus type 1 (HSV-1) alkaline nuclease, encoded by the UL12 gene, plays an important role in HSV-1 replication, as a null mutant of UL12 displays a severe growth defect. Although the precise in vivo role of UL12 has not yet been determined, several in vitro activities have been identified for the protein, including endo- and exonuclease activities, interaction with the HSV-1 single-stranded DNA binding protein ICP8, and an ability to promote strand exchange in conjunction with ICP8. In this study, we examined a naturally occurring N-terminally truncated version of UL12 called UL12.5. Previous studies showing that UL12.5 exhibits nuclease activity but is unable to complement a UL12 null virus posed a dilemma and suggested that UL12.5 may lack a critical activity possessed by the full-length protein, UL12. We constructed a recombinant baculovirus capable of expressing UL12.5 and purified soluble UL12.5 from infected insect cells. The purified UL12.5 exhibited both endo- and exonuclease activities but was less active than UL12. Like UL12, UL12.5 could mediate strand exchange with ICP8 and could also be coimmunoprecipitated with ICP8. The primary difference between the two proteins was in their intracellular localization, with UL12 localizing to the nucleus and UL12.5 remaining in the cytoplasm. We mapped a nuclear localization signal to the N terminus of UL12, the domain absent from UL12.5. In addition, when UL12.5 was overexpressed so that some of the enzyme leaked into the nucleus, it was able to partially complement the UL12 null mutant.


2003 ◽  
Vol 77 (5) ◽  
pp. 3307-3311 ◽  
Author(s):  
Sarah M. Richart ◽  
Scott A. Simpson ◽  
Claude Krummenacher ◽  
J. Charles Whitbeck ◽  
Lewis I. Pizer ◽  
...  

ABSTRACT Primary cultures of rat and mouse sensory neurons were used to study the entry of herpes simplex virus type 1 (HSV-1). Soluble, truncated nectin-1 but not HveA prevented viral entry. Antibodies against nectin-1 also blocked infection of rat neurons. These results indicate that nectin-1 is the primary receptor for HSV-1 infection of sensory neurons.


Author(s):  
Т.З. Керимов ◽  
В.П. Соболев ◽  
М.А. Соболева ◽  
Н.А. Гаврилова ◽  
С.А. Борзенок

В обзоре представлено описание патофизиологических механизмов герпесвирусной инфекции. Согласно данным медицинской статистики, вирусом простого герпеса 1 типа инфицировано большинство населения планеты. В развивающихся странах данный вирус является ведущей инфекционной причиной поражения роговицы. Также вирусу простого герпеса 1 типа отводится роль одного из факторов, приводящих к отторжению трансплантата роговицы. Вышеописанные патологические явления сопряжены с перестройкой клеточных систем в ответ на вирусное воздействие. Недавние открытия в данной области обнаружили значительный вклад трансмембранных и эндосомальных Toll-подобных рецепторов во врожденный противовирусный клеточный ответ. Показано, что эндосомальные Toll-подобные рецепторы 3 типа экспрессируются в кератоцитах только после их фенотипического перехода в фибробласты. Данная трансформация обычно происходит в результате механических и патогенных воздействий на роговицу. Изменение рецепторного состава клеток в ответ на герпесвирусную инвазию вызывает выработку интерферонов 1 типа - интерферона-альфа, интерферона-бета, и синтезу провоспалительных цитокинов, что приводит к вирусной деконтаминации. This review describes pathophysiological mechanisms of herpes virus infection in cornea cells. It has been previously reported that herpes simplex virus type 1 (HSV-1) infects most of the world’s population. In developing countries, HSV-1 is the leading infectious cause of corneal damage. Also, herpes simplex virus type 1 was assigned the role of one of the factors leading to rejection of the corneal transplant. These pathological phenomena are associated with restructuring of cellular systems in response to viral exposure. Recent discoveries have revealed a significant contribution of transmembrane and endosomal Toll-like receptors to the innate antiviral cell response. It is well known that endosomal Toll-like receptors-3 are expressed in keratocytes only after their phenotypic transformation to fibroblasts. This transformation usually occurs as a result of mechanical or infectious impact on the cornea. Changes in the receptor composition of cells as a response to herpes virus invasion is the main cause of type 1 interferons (interferon-alpha and interferon-beta) production and expression of proinflammatory cytokines, which leads to viral decontamination.


2007 ◽  
Vol 82 (6) ◽  
pp. 2661-2672 ◽  
Author(s):  
Roger D. Everett ◽  
Carlos Parada ◽  
Philippe Gripon ◽  
Hüseyin Sirma ◽  
Anne Orr

ABSTRACT Herpes simplex virus type 1 (HSV-1) mutants that fail to express the viral immediate-early protein ICP0 have a pronounced defect in viral gene expression and plaque formation in limited-passage human fibroblasts. ICP0 is a RING finger E3 ubiquitin ligase that induces the degradation of several cellular proteins. PML, the organizer of cellular nuclear substructures known as PML nuclear bodies or ND10, is one of the most notable proteins that is targeted by ICP0. Depletion of PML from human fibroblasts increases ICP0-null mutant HSV-1 gene expression, but not to wild-type levels. In this study, we report that depletion of Sp100, another major ND10 protein, results in a similar increase in ICP0-null mutant gene expression and that simultaneous depletion of both proteins complements the mutant virus to a greater degree. Although chromatin assembly and modification undoubtedly play major roles in the regulation of HSV-1 infection, we found that inhibition of histone deacetylase activity with trichostatin A was unable to complement the defect of ICP0-null mutant HSV-1 in either normal or PML-depleted human fibroblasts. These data lend further weight to the hypothesis that ND10 play an important role in the regulation of HSV-1 gene expression.


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