The EICP27 protein of equine herpesvirus 1 is recruited to viral promoters by its interaction with the immediate-early protein.
Abstract: The equine herpesvirus 1 (EHV-1) EICP27 protein cooperates with either the immediate-early (IE) or the EICP0 protein to synergistically trans-activate viral promoters. GST-pulldown and co-immunoprecipitation assays revealed that the EICP27 protein's cooperation with the IE or the EICP0 protein involves its physical interaction with these viral proteins. In the case of the IE-EICP27 protein interaction, IE residues 424 to 826 and EICP27 residues 41 to 206 harbor the interactive domains. Electrophoretic mobility shift assays (EMSA) suggested that the EICP27 protein is not a sequence-specific DNA-binding protein as it fails to directly bind to the IE promoter, the early EICP27, EICP0, and TK promoters, or the late gD and IR5 promoters. However, EMSA studies also showed that the interaction of the IE and EICP27 proteins results in the recruitment of the EICP27 protein to representative early promoters. These results support our hypothesis that the EICP27 protein participates in the trans-activation of EHV-1 promoters, and suggest its presence within RNA polymerase II preinitiation complexes that assemble at viral promoters.
Publication Date: 2005-02-15 PubMed ID: 15708594DOI: 10.1016/j.virol.2004.12.014Google Scholar: Lookup
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- Journal Article
- Research Support
- U.S. Gov't
- P.H.S.
Summary
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This research paper discusses the role of the EICP27 protein from equine herpesvirus 1 (EHV-1) in triggering the activation of viral promoters through its interaction with certain other viral proteins.
Key Findings of the Research
- The study primarily focused on the EICP27 protein of EHV-1 and its collaboration with either the immediate-early (IE) or the EICP0 protein. The research found that these interactions lead to the synergistic trans-activation of viral promoters, which are regions of DNA that initiate transcription of a particular gene.
- Researchers applied GST-pulldown and co-immunoprecipitation methods. These widely used techniques in molecular biology helped them confirm that the cooperation of EICP27 with the IE or the EICP0 protein is based on its physical interaction with these viral proteins.
- The study mapped out exact portions of the IE and EICP27 proteins that interact, specifically IE’s residues 424 to 826 and EICP27’s residues 41 to 206. These identified areas are key to facilitating the interaction between the two proteins.
Role of EICP27 in DNA Binding
- The research used Electrophoretic Mobility Shift Assays (EMSA) to better understand the role of EICP27 in DNA binding. The assays indicated that EICP27 can’t directly bind to the promoter regions of several key EHV-1 genes on its own, meaning that it is not a sequence-specific DNA-binding protein.
- However, EMSA also showed that when the EICP27 protein interacts with the IE protein, it is brought to early promoters. This process is known as recruitment and is crucial in gene transcription as it brings necessary proteins to the site of action.
Implications and Further Possibilities
- Collectively, these findings validate the researchers’ initial hypothesis that the EICP27 protein is implicated in the trans-activation of EHV-1 promoters. This means that EICP27 plays an important role in initiating the process where an information from a gene is used to build a functional product like a protein.
- The results also suggest that EICP27 may be part of the RNA polymerase II preinitiation complexes that assemble at viral promoters. This complex is responsible for kicking off transcription, so EICP27’s presence would suggest a significant role in the transcription process of EHV-1.
Cite This Article
APA
Albrecht RA, Kim SK, O'Callaghan DJ.
(2005).
The EICP27 protein of equine herpesvirus 1 is recruited to viral promoters by its interaction with the immediate-early protein.
Virology, 333(1), 74-87.
https://doi.org/10.1016/j.virol.2004.12.014 Publication
Researcher Affiliations
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130-3932, USA.
MeSH Terms
- Animals
- Base Sequence
- Cell Line
- Gene Expression Regulation, Viral
- Herpesvirus 1, Equid / physiology
- Immediate-Early Proteins / physiology
- Mice
- Promoter Regions, Genetic / physiology
- Protein Binding
- Protein Interaction Mapping
- Viral Proteins / physiology
- Virus Replication / physiology
Grant Funding
- P20 RR018724 / NCRR NIH HHS
- R01 AI022001 / NIAID NIH HHS
- 1P20-RR18724 / NCRR NIH HHS
- AI-22001 / NIAID NIH HHS
Citations
This article has been cited 10 times.- Liu C, Cheng A, Wang M, Chen S, Jia R, Zhu D, Liu M, Sun K, Yang Q, Chen X. Duck enteritis virus UL54 is an IE protein primarily located in the nucleus.. Virol J 2015 Nov 25;12:198.
- 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.
- Ahn BC, Zhang Y, O'Callaghan DJ. The equine herpesvirus-1 (EHV-1) IR3 transcript downregulates expression of the IE gene and the absence of IR3 gene expression alters EHV-1 biological properties and virulence.. Virology 2010 Jul 5;402(2):327-37.
- 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.
- Ebner PD, Kim SK, O'Callaghan DJ. Biological and genotypic properties of defective interfering particles of equine herpesvirus 1 that mediate persistent infection.. Virology 2008 Nov 10;381(1):98-105.
- Palmeri D, Spadavecchia S, Carroll KD, Lukac DM. Promoter- and cell-specific transcriptional transactivation by the Kaposi's sarcoma-associated herpesvirus ORF57/Mta protein.. J Virol 2007 Dec;81(24):13299-314.
- 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.
- Ebner PD, O'Callaghan DJ. Genetic complexity of EHV-1 defective interfering particles and identification of novel IR4/UL5 hybrid proteins produced during persistent infection.. Virus Genes 2006 Jun;32(3):313-20.
- 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.
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