scholarly journals The Antiapoptotic Herpes Simplex Virus Glycoprotein J Localizes to Multiple Cellular Organelles and Induces Reactive Oxygen Species Formation

2007 ◽  
Vol 82 (2) ◽  
pp. 617-629 ◽  
Author(s):  
Martine Aubert ◽  
Zheng Chen ◽  
Robin Lang ◽  
Chung H. Dang ◽  
Carla Fowler ◽  
...  

ABSTRACT The Us5 gene of herpes simplex virus (HSV) encodes glycoprotein J (gJ). The only previously reported function of gJ was its ability to inhibit apoptosis. However, the mechanism by which gJ prevents apoptosis is not understood, and it is not known whether gJ mediates additional cellular effects. In this study, we evaluated the expression, localization, and cellular effects of Us5/gJ. Us5 was first expressed 4 h after infection. gJ was detectable at 6 h and was expressed in glycosylated and unglycosylated forms. Us5 was regulated as a late gene, with partial dependency on DNA replication for expression. Us5 expression was delayed in the absence of ICP22; furthermore, expression of Us5 in trans protected cells from apoptosis induced by an HSV mutant with deletion of ICP27, suggesting that the antiapoptotic effects of ICP22 and ICP27 are mediated in part through effects on gJ expression. Within HSV-infected or Us5-transfected cells, gJ was distributed widely, especially to the endoplasmic reticulum, trans-Golgi network, and early endosomes. gJ interacted with FoF1 ATP synthase subunit 6 by a yeast two-hybrid screen and had strong antiapoptotic effects, which were mediated by protein rather than mRNA. Antiapoptotic activity required the extracellular and transmembrane domains of gJ, but not the intracellular domain. Consistent with inhibition of FoF1 ATP synthase function, Us5 was required for HSV-induced reactive oxygen species (ROS) formation, and gJ was sufficient to induce ROS in Us5-transfected cells. Thus, HSV gJ is a multifunctional protein, modulating other cellular processes in addition to inhibition of apoptosis.

Author(s):  
Tae In Kim ◽  
Eun-Bin Kwon ◽  
You-Chang Oh ◽  
Younghoon Go ◽  
Jang-Gi Choi

Herpes simplex virus type 1 (HSV-1) is ubiquitous in many populations despite the use of acyclovir or related nucleoside analogs for treating infection. Drug resistance impairs the treatment of HSV-infected individuals who have immune deficits, underscoring the need for new safe and effective antiviral agents. Mori ramulus (the young twig of Morus alba L.) has long been used to treat diseases in Korea, Japan, and China. Recent studies have reported multiple pharmacological activities of Mori ramulus and its constituent morusin, but their effects on HSV-1 remain unknown. Here, we found that treatment with Mori ramulus ethanol extract (MRE) significantly reduced the replication of fluorescently labeled HSV-1 in Vero cells and inhibited the expression of HSV-1 envelope glycoprotein D (gD) and tegument protein VP16. MRE, furthermore, blocked HSV-1-induced production of reactive oxygen species (ROS), and this mediated the inhibition of viral replication. We identified morusin as the active antiviral component of MRE and found that morusin post-treatment was sufficient to inhibit viral gD and VP16 in addition to HSV-1-induced ROS production. Therefore, the inhibition of HSV-1-induced ROS may explain the antiviral activity of MRE against HSV-1. MRE or its component morusin may be potentially developed for anti-HSV-1 agents.


2004 ◽  
Vol 78 (13) ◽  
pp. 6744-6757 ◽  
Author(s):  
Patrick Lomonte ◽  
Joëlle Thomas ◽  
Pascale Texier ◽  
Cécile Caron ◽  
Saadi Khochbin ◽  
...  

ABSTRACT This study describes the physical and functional interactions between ICP0 of herpes simplex virus type 1 and class II histone deacetylases (HDACs) 4, 5, and 7. Class II HDACs are mainly known for their participation in the control of cell differentiation through the regulation of the activity of the transcription factor MEF2 (myocyte enhancer factor 2), implicated in muscle development and neuronal survival. Immunofluorescence experiments performed on transfected cells showed that ICP0 colocalizes with and reorganizes the nuclear distribution of ectopically expressed class I and II HDACs. In addition, endogenous HDAC4 and at least one of its binding partners, the corepressor protein SMRT (for silencing mediator of retinoid and thyroid receptor), undergo changes in their nuclear distribution in ICP0-transfected cells. As a result, during infection endogenous HDAC4 colocalizes with ICP0. Coimmunoprecipitation and glutathione S-transferase pull-down assays confirmed that class II but not class I HDACs specifically interacted with ICP0 through their amino-terminal regions. This region, which is not conserved in class I HDACs but homologous to the MITR (MEF2-interacting transcription repressor) protein, is responsible for the repression, in a deacetylase-independent manner, of MEF2 by sequestering it under an inactive form in the nucleus. Consequently, we show that ICP0 is able to overcome the HDAC5 amino-terminal- and MITR-induced MEF2A repression in gene reporter assays. This is the first report of a viral protein interacting with and controlling the repressor activity of class II HDACs. We discuss the putative consequences of such an interaction for the biology of the virus both during lytic infection and reactivation from latency.


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