scholarly journals Peptide transport activity of the transporter associated with antigen processing (TAP) is inhibited by an early protein of equine herpesvirus-1

2004 ◽  
Vol 85 (2) ◽  
pp. 349-353 ◽  
Author(s):  
Aruna P. N. Ambagala ◽  
Raju S. Gopinath ◽  
S. Srikumaran
Keyword(s):  
Antigen Processing ◽  
Protein S ◽  
Class I ◽  
Peptide Transport ◽  
Equine Herpesvirus ◽  
Equine Herpesvirus 1 ◽  
Early Protein ◽  
Infected Cells ◽  
Herpesvirus 1

Equine herpesvirus-1 (EHV-1) downregulates surface expression of major histocompatibility complex (MHC) class I molecules on infected cells. The objective of this study was to investigate whether EHV-1 interferes with peptide translocation by the transporter associated with antigen processing (TAP) and to identify the proteins responsible. Using an in vitro transport assay, we showed that EHV-1 inhibited transport of peptides by TAP as early as 2 h post-infection (p.i). Complete shutdown of peptide transport was observed by 8 h p.i. Furthermore, pulse–chase experiments revealed that maturation of class I molecules in the endoplasmic reticulum (ER) was delayed in EHV-1-infected cells, which may be due to reduced availability of peptides in the ER as a result of TAP inhibition. Metabolic inhibition studies indicated that an early protein(s) of EHV-1 is responsible for this effect.

scholarly journals Mapping the Sequences That Mediate Interaction of the Equine Herpesvirus 1 Immediate-Early Protein and Human TFIIB

2001 ◽  
Vol 75 (21) ◽  
pp. 10219-10230 ◽  
Author(s):  
Hyung K. Jang ◽  
Randy A. Albrecht ◽  
Kimberly A. Buczynski ◽  
Seong K. Kim ◽  
Wilbert A. Derbigny ◽  
...  
Keyword(s):  
Binding Domain ◽  
Immediate Early ◽  
Equine Herpesvirus ◽  
Binding Assays ◽  
Kinase Gene ◽  
Equine Herpesvirus 1 ◽  
Physiological Importance ◽  
Early Protein ◽  
Herpesvirus 1

ABSTRACT The sole immediate-early (IE) gene of equine herpesvirus 1 encodes a 1,487-amino-acid (aa) regulatory phosphoprotein that independently activates expression of early viral genes. Coimmunoprecipitation assays demonstrated that the IE protein physically interacts with the general transcription factor TFIIB. Using a variety of protein-binding assays that employed a panel of IE truncation and deletion mutants expressed as in vitro-synthesized or glutathione S-transferase fusion proteins, we mapped a TFIIB-binding domain to aa 407 to 757 of the IE protein. IE mutants carrying internal deletions of aa 426 to 578 and 621 to 757 were partially defective for TFIIB binding, indicating that aa 407 to 757 may harbor more than one TFIIB-binding domain. The interaction between the IE protein and TFIIB is of physiological importance, as evidenced by transient-cotransfection assays. Partial deletion of the TFIIB-binding domain within the IE protein inhibited its ability to activate expression of the viral thymidine kinase gene, a representative early promoter, and of the IR5 gene, a representative late promoter, by greater than 20 and 50%, respectively. These results indicate that the interaction of the IE protein with TFIIB is necessary for its full transactivation function and that the IE-TFIIB interaction may be part of the mechanism by which the IE protein activates transcription.

scholarly journals Exogenous Expression of Equine MHC Class I Molecules in Mice Increases Susceptibility to Equine Herpesvirus 1 Pulmonary Infection

2019 ◽  
Vol 56 (5) ◽  
pp. 703-710 ◽  
Author(s):  
Erina Minato ◽  
Keisuke Aoshima ◽  
Atsushi Kobayashi ◽  
Naomi Ohnishi ◽  
Nobuya Sasaki ◽  
...  
Keyword(s):  
Mhc Class I ◽  
Virus Antigen ◽  
Class I ◽  
Equine Herpesvirus ◽  
Class I Mhc ◽  
Equine Herpesvirus 1 ◽  
Exogenous Expression ◽  
Herpesvirus 1 ◽  
Entry Receptor

Equine herpesvirus 1 (EHV-1) uses equine major histocompatibility complex class I (MHC class I) as an entry receptor. Exogenous expression of equine MHC class I genes in murine cell lines confers susceptibility to EHV-1 infection. To examine the in vivo role of equine MHC class I as an entry receptor for EHV-1, we generated transgenic (Tg) mice expressing equine MHC class I under the control of the CAG promoter. Equine MHC class I protein was expressed in the liver, spleen, lung, and brain of Tg mice, which was confirmed by Western blot. However, equine MHC class I antigen was only detected in bronchiolar epithelium and not in other tissues, using the immunofluorescence method employed in this study. Both Tg and wild-type (WT) mice developed pneumonia 3 days after intranasal infection with EHV-1. The bronchiolar epithelial cells of Tg mice showed more severe necrosis, compared with those in WT mice. In addition, the number of virus antigen-positive cells in the lungs was higher in Tg mice than in WT mice. These results suggest that exogenous expression of equine MHC class I renders mice more susceptible to EHV-1 infection.

scholarly journals The Equine Herpesvirus 1 US2 Homolog Encodes a Nonessential Membrane-Associated Virion Component

1999 ◽  
Vol 73 (4) ◽  
pp. 3430-3437 ◽  
Author(s):  
Alexandra Meindl ◽  
Nikolaus Osterrieder
Keyword(s):  
Amino Acids ◽  
Plasma Membrane ◽  
Secretory Pathway ◽  
Fluorescent Protein ◽  
Viral Envelope ◽  
Equine Herpesvirus ◽  
Equine Herpesvirus 1 ◽  
Amino Terminal ◽  
Infected Cells ◽  
Herpesvirus 1

ABSTRACT Experiments were conducted to analyze the equine herpesvirus 1 (EHV-1) gene 68 product which is encoded by the EHV-1 US2 homolog. An antiserum directed against the amino-terminal 206 amino acids of the EHV-1 US2 protein specifically detected a protein with an M r of 34,000 in cells infected with EHV-1 strain RacL11. EHV-1 strain Ab4 encodes a 44,000-M r Us2 protein, whereas vaccine strain RacH, a high-passage derivative of RacL11, encodes a 31,000-M r Us2 polypeptide. Irrespective of its size, the US2 protein was incorporated into virions. The EHV-1 US2 protein localized to membrane and nuclear fractions of RacL11-infected cells and to the envelope fraction of purified virions. To monitor intracellular trafficking of the protein, the green fluorescent protein (GFP) was fused to the carboxy terminus of the EHV-1 US2 protein or to a truncated US2 protein lacking a stretch of 16 hydrophobic amino acids at the extreme amino terminus. Both fusion proteins were detected at the plasma membrane and accumulated in the vicinity of nuclei of transfected cells. However, trafficking of either GFP fusion protein through the secretory pathway could not be demonstrated, and the EHV-1 US2 protein lacked detectable N- and O-linked carbohydrates. Consistent with the presence of the US2 protein in the viral envelope and plasma membrane of infected cells, a US2-negative RacL11 mutant (L11ΔUS2) exhibited delayed penetration kinetics and produced smaller plaques compared with either wild-type RacL11 or a US2-repaired virus. After infection of BALB/c mice with L11ΔUS2, reduced pathogenicity compared with the parental RacL11 virus and the repaired virus was observed. It is concluded that the EHV-1 US2 protein modulates virus entry and cell-to-cell spread and appears to support sustained EHV-1 replication in vivo.

scholarly journals In vitro susceptibility of six isolates of equine herpesvirus 1 to acyclovir, ganciclovir, cidofovir, adefovir, PMEDAP and foscarnet

2007 ◽  
Vol 122 (1-2) ◽  
pp. 43-51 ◽  
Author(s):  
B GARRE ◽  
K VANDERMEULEN ◽  
J NUGENT ◽  
J NEYTS ◽  
S CROUBELS ◽  
...  
Keyword(s):  
Equine Herpesvirus ◽  
In Vitro Susceptibility ◽  
Equine Herpesvirus 1 ◽  
Herpesvirus 1

scholarly journals The EICP22 Protein of Equine Herpesvirus 1 Physically Interacts with the Immediate-Early Protein and with Itself To Form Dimers and Higher-Order Complexes

2000 ◽  
Vol 74 (3) ◽  
pp. 1425-1435 ◽  
Author(s):  
Wilbert A. Derbigny ◽  
Seong K. Kim ◽  
Gretchen B. Caughman ◽  
Dennis J. O'Callaghan
Keyword(s):  
Amino Acids ◽  
Regulatory Proteins ◽  
Deletion Mutants ◽  
Yeast Two Hybrid ◽  
Equine Herpesvirus 1 ◽  
Early Protein ◽  
Herpesvirus 1 ◽  
Order Complexes ◽  
Two Hybrid

ABSTRACT The EICP22 protein (EICP22P) of Equine herpesvirus 1(EHV-1) is an early protein that functions synergistically with other EHV-1 regulatory proteins to transactivate the expression of early and late viral genes. We have previously identified EICP22P as an accessory regulatory protein that has the ability to enhance the transactivating properties and the sequence-specific DNA-binding activity of the EHV-1 immediate-early protein (IEP). In the present study, we identify EICP22P as a self-associating protein able to form dimers and higher-order complexes during infection. Studies with the yeast two-hybrid system also indicate that physical interactions occur between EICP22P and IEP and that EICP22P self-aggregates. Results from in vitro and in vivo coimmunoprecipitation experiments and glutathioneS-transferase (GST) pull-down studies confirmed a direct protein-protein interaction between EICP22P and IEP as well as self-interactions of EICP22P. Analyses of infected cells by laser-scanning confocal microscopy with antibodies specific for IEP and EICP22P revealed that these viral regulatory proteins colocalize in the nucleus at early times postinfection and form aggregates of dense nuclear structures within the nucleoplasm. Mutational analyses with a battery of EICP22P deletion mutants in both yeast two-hybrid and GST pull-down experiments implicated amino acids between positions 124 and 143 as the critical domain mediating the EICP22P self-interactions. Additional in vitro protein-binding assays with a library of GST-EICP22P deletion mutants identified amino acids mapping within region 2 (amino acids [aa] 65 to 196) and region 3 (aa 197 to 268) of EICP22P as residues that mediate its interaction with IEP.

scholarly journals Mitogen stimulation favours replication of equine herpesvirus-1 in equine blood mononuclear cells by inducing cell proliferation and formation of close intercellular contacts

2001 ◽  
Vol 82 (8) ◽  
pp. 1951-1957 ◽  
Author(s):  
Karen M. van der Meulen ◽  
Hans J. Nauwynck ◽  
Maurice B. Pensaert
Keyword(s):  
Cell Cycle ◽  
Mononuclear Cells ◽  
Equine Herpesvirus ◽  
Equine Herpesvirus 1 ◽  
Mitogen Stimulation ◽  
Blood Mononuclear Cells ◽  
Intercellular Contacts ◽  
M Phase ◽  
Infected Cells ◽  
Herpesvirus 1

In the present study, equine herpesvirus-1 (EHV-1)-infected cells were identified in ionomycin/phorbol dibutyrate (IONO/PDB)-stimulated peripheral blood mononuclear cells (PBMC) and the mechanism by which stimulation increases the percentage of infected cells was examined. In the population of viral antigen-positive PBMC, 38·4±4·5% were CD5+ T-lymphocytes (18·1±3·2% CD4+ 13·6±1·8% CD8+), 18·1±5·4% were B-lymphocytes, 8·5±3·9% were monocytes and 35% remained unidentified. The role of the cell cycle in the increased susceptibility to EHV-1 upon stimulation was examined by stimulating PBMC for 0, 12, 24 or 36 h prior to inoculation. A high correlation was found between the increase of cells in the S- (r=0·974) and G2/M-phase (r=0·927) at the moment of inoculation and the increase of infected cells at 12 h post-inoculation (p.i.). This suggests that a specific stage of the S-phase or S- and G2/M-phase facilitates virus replication. At 24 h p.i. lower correlations were found, suggesting that other effects are involved. From 12 h after addition of IONO/PDB, formation of clusters of PBMC became manifest. We examined whether close intercellular contacts in these clusters facilitated cell-to-cell transmission of EHV-1. Between 8 and 17 h p.i., the percentage of clusters containing adjacent infected cells increased from 1·6 to 13·4% and the maximal number of adjacent infected cells increased from two to four. Confocal microscopy visualized close intercellular contacts between adjacent infected cells. It can be concluded that mitogen stimulation favours EHV-1 infection of PBMC (i) by initiating specific cell cycle events and (ii) by inducing formation of clusters, thereby facilitating transmission of virus between cells.

scholarly journals The Equine Herpesvirus 1 Immediate-Early Protein Interacts with EAP, a Nucleolar-Ribosomal Protein

Virology ◽  
2001 ◽  
Vol 279 (1) ◽  
pp. 173-184 ◽  
Author(s):  
Seong K. Kim ◽  
Kimberly A. Buczynski ◽  
Gretchen B. Caughman ◽  
Dennis J. O'Callaghan
Keyword(s):  
Ribosomal Protein ◽  
Immediate Early ◽  
Equine Herpesvirus ◽  
Equine Herpesvirus 1 ◽  
Early Protein ◽  
Herpesvirus 1
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