The equine herpesvirus 1 immediate-early protein interacts with EAP, a nucleolar-ribosomal protein.
Abstract: The equine herpesvirus 1 (EHV-1) immediate-early (IE) phosphoprotein is essential for the activation of transcription from viral early and late promoters and regulates transcription from its own promoter. The IE protein of 1487 amino acids contains a serine-rich tract (SRT) between residues 181 and 220. Deletion of the SRT decreased transactivation activity of the IE protein. Previous results from investigation of the ICP4 protein, the IE homolog of herpes simplex virus 1 (HSV-1), revealed that a domain containing a serine-rich tract interacts with EAP (Epstein-Barr virus-encoded small nuclear RNA-associated protein), a 15-kDa nucleolar-ribosomal protein (R. Leopardi, and B. Roizman, Proc. Natl. Acad. Sci. USA 93, 4572-4576, 1996). DNA binding assays revealed that (i) glutathione S-transferase (GST)-EAP disrupted the binding of HSV-1 ICP4 to its cognate DNA in a dose-dependent manner, (ii) GST-EAP interacted with the EHV-1 IE protein, but did not disrupt its binding to its cognate site in viral DNA. GST-pulldown assays indicated that the SRT of the IE protein is required for physical interaction with EAP. The IE protein and EAP colocalized in the cytoplasm of the infected equine ETCC cells at late times of the infection cycle. This latter finding may be important in EHV-1 gene regulation since late viral gene expression is greatly influenced by the EICP0 trans-activator protein whose function is antagonized by the IE protein.
Copyright 2001 Academic Press.
Publication Date: 2001-01-09 PubMed ID: 11145900DOI: 10.1006/viro.2000.0725Google Scholar: Lookup
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- Journal Article
- Research Support
- U.S. Gov't
- P.H.S.
Summary
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The research paper describes how the Immediate-Early (IE) protein of Equine Herpesvirus 1 (EHV-1) interacts with a cellular protein called EAP, which may be important in regulating virus gene expression.
Background and Purpose of the Study
- The equine herpesvirus 1 (EHV-1) is a common horse virus that can cause respiratory disease, neurological disorders, and abortions.
- In this study, the researchers focused on an essential early-stage protein produced during the EHV-1’s lifecycle called the immediate-early (IE) protein.
- The IE protein activates the transcription stage of the EHV-1 DNA to enable replication and subsequent stages. It is made up of 1487 amino acids, among which there is a serine-rich tract (SRT) located between residues 181 and 220.
- Research on the counterpart of this protein in the herpes simplex virus (HSV-1) shows that it interacts with Epstein-Barr virus-encoded small nuclear RNA-associated protein (EAP), a nucleolar-ribosomal protein. So, the research aims to understand if a similar interaction occurs with EHV-1’s IE protein.
Study Methodology and Findings
- The study examined how the EHV-1 IE protein interacts with the EAP.
- DNA binding tests revealed that:
- Using a mechanism of protein disruption, the combination of Glutathione S-transferase (GST) and EAP was found to break HSV-1’s IE protein-DNA bonding, wherein GST-EAP was dose-dependent.
- However, GST-EAP interacted with the EHV-1’s IE protein but didn’t disrupt its binding with its DNA.
- Pulldown assay experiments were done to identify physical interactions between proteins. Here, it was found that the SRT of the EHV-1’s IE protein is a prerequisite for a physical interaction with the EAP.
- The EHV-1’s IE protein and EAP were found to colocalize in the cytoplasm of infected ETCC cells at later stages of the infection cycle, suggesting a role in EHV-1 genetic regulation.
Significance of the Study
- These findings clarified the critical role of the IE protein’s SRT in interacting with the EAP, and its potential effect on viral gene expression regulation through the latter stages of infection, especially by inhibiting the function of EICP0 trans-activator protein.
- This research could help future studies better understand the viral replication process and potentially identify new targets for treating EHV-1 infections.
Cite This Article
APA
Kim SK, Buczynski KA, Caughman GB, O'Callaghan DJ.
(2001).
The equine herpesvirus 1 immediate-early protein interacts with EAP, a nucleolar-ribosomal protein.
Virology, 279(1), 173-184.
https://doi.org/10.1006/viro.2000.0725 Publication
Researcher Affiliations
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, 71130-3932, USA.
MeSH Terms
- Animals
- Cell Line
- Chloramphenicol O-Acetyltransferase / metabolism
- Cytoplasm / metabolism
- DNA, Viral / metabolism
- Gene Deletion
- Glutathione Transferase / genetics
- Glutathione Transferase / metabolism
- Herpesviridae Infections / virology
- Herpesvirus 1, Equid / genetics
- Herpesvirus 1, Equid / metabolism
- Immediate-Early Proteins / chemistry
- Immediate-Early Proteins / genetics
- Immediate-Early Proteins / metabolism
- Mice
- RNA-Binding Proteins / metabolism
- Recombinant Fusion Proteins / metabolism
- Serine / chemistry
- Serine / genetics
- Transcriptional Activation
Grant Funding
- R01 AI022001 / NIAID NIH HHS
- AI-22001 / NIAID NIH HHS
Citations
This article has been cited 14 times.- Kim SK, Shakya AK, O'Callaghan DJ. Full trans-activation mediated by the immediate-early protein of equine herpesvirus 1 requires a consensus TATA box, but not its cognate binding sequence. Virus Res 2016 Jan 4;211:222-32.
- Kim SK, Shakya AK, Kim S, O'Callaghan DJ. Functional Characterization of the Serine-Rich Tract of Varicella-Zoster Virus IE62. J Virol 2016 Jan 15;90(2):959-71.
- Dai G, Kim S, O'Callaghan DJ, Kim SK. Development of a bacterial artificial chromosome (BAC) recombineering procedure using galK-untranslated region (UTR) for the mutation of diploid genes. J Virol Methods 2012 Jun;182(1-2):18-26.
- Kim SK, Kim S, Dai G, Zhang Y, Ahn BC, O'Callaghan DJ. Identification of functional domains of the IR2 protein of equine herpesvirus 1 required for inhibition of viral gene expression and replication. Virology 2011 Sep 1;417(2):430-42.
- Gregorovic G, Bosshard R, Karstegl CE, White RE, Pattle S, Chiang AK, Dittrich-Breiholz O, Kracht M, Russ R, Farrell PJ. Cellular gene expression that correlates with EBER expression in Epstein-Barr Virus-infected lymphoblastoid cell lines. J Virol 2011 Apr;85(7):3535-45.
- Houmani JL, Davis CI, Ruf IK. Growth-promoting properties of Epstein-Barr virus EBER-1 RNA correlate with ribosomal protein L22 binding. J Virol 2009 Oct;83(19):9844-53.
- Breitenbach JE, Ebner PD, O'Callaghan DJ. The IR4 auxiliary regulatory protein expands the in vitro host range of equine herpesvirus 1 and is essential for pathogenesis in the murine model. Virology 2009 Jan 20;383(2):188-94.
- Ahn BC, Breitenbach JE, Kim SK, O'Callaghan DJ. The equine herpesvirus-1 IR3 gene that lies antisense to the sole immediate-early (IE) gene is trans-activated by the IE protein, and is poorly expressed to a protein. Virology 2007 Jun 20;363(1):15-25.
- Kim SK, Ahn BC, Albrecht RA, O'Callaghan DJ. The unique IR2 protein of equine herpesvirus 1 negatively regulates viral gene expression. J Virol 2006 May;80(10):5041-9.
- Buczynski KA, Kim SK, O'Callaghan DJ. Initial characterization of 17 viruses harboring mutant forms of the immediate-early gene of equine herpesvirus 1. Virus Genes 2005 Oct;31(2):229-39.
- Kim SK, Albrecht RA, O'Callaghan DJ. A negative regulatory element (base pairs -204 to -177) of the EICP0 promoter of equine herpesvirus 1 abolishes the EICP0 protein's trans-activation of its own promoter. J Virol 2004 Nov;78(21):11696-706.
- Ou CJ, Wong ML, Chang TJ. A TEF-1-element is required for activation of the promoter of pseudorabies virus glycoprotein X gene by IE180. Virus Genes 2002 Dec;25(3):241-53.
- Ou CJ, Wong ML, Huang C, Chang TJ. Suppression of promoter activity of the LAT gene by IE180 of pseudorabies virus. Virus Genes 2002 Dec;25(3):227-39.
- Jang HK, Albrecht RA, Buczynski KA, Kim SK, Derbigny WA, O'Callaghan DJ. Mapping the sequences that mediate interaction of the equine herpesvirus 1 immediate-early protein and human TFIIB. J Virol 2001 Nov;75(21):10219-30.
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