TY - JOUR
T1 - The equine herpesvirus 1 immediate-early protein interacts with EAP, a nucleolar-ribosomal protein
AU - Kim, Seong K.
AU - Buczynski, Kimberly A.
AU - Caughman, Gretchen B.
AU - O'Callaghan, Dennis J.
N1 - Funding Information:
We thank Stephen R. Jennings for providing the anti-ICP4 monoclonal antibody 58s and Mrs. Suzanne Zavecz for excellent technical assistance. Support for this investigation was obtained from Public Health Service research Grant AI-22001 from the National Institutes of Health.
PY - 2001/1/20
Y1 - 2001/1/20
N2 - 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.
AB - 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.
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U2 - 10.1006/viro.2000.0725
DO - 10.1006/viro.2000.0725
M3 - Article
C2 - 11145900
AN - SCOPUS:0035916009
SN - 0042-6822
VL - 279
SP - 173
EP - 184
JO - Virology
JF - Virology
IS - 1
ER -