Article ID Journal Published Year Pages File Type
3424791 Virology 2011 13 Pages PDF
Abstract

The equine herpesvirus 1 (EHV-1) negative regulatory IR2 protein (IR2P), an early 1,165-amino acid (aa) truncated form of the 1487-aa immediate-early protein (IEP), lacks the trans-activation domain essential for IEP activation functions but retains domains for binding DNA, TFIIB, and TBP and the nuclear localization signal. IR2P mutants of the N-terminal region which lack either DNA-binding activity or TFIIB-binding activity were unable to down-regulate EHV-1 promoters. In EHV-1-infected cells expressing full-length IR2P, transcription and protein expression of viral regulatory IE, early EICP0, IR4, and UL5, and late ETIF genes were dramatically inhibited. Viral DNA levels were reduced to 2.1% of control infected cells, but were vey weakly affected in cells that express the N-terminal 706 residues of IR2P. These results suggest that IR2P function requires the two N-terminal domains for binding DNA and TFIIB as well as the C-terminal residues 707 to 1116 containing the TBP-binding domain.

► We examine the functional domains of IR2P that mediates negative regulation. ► IR2P inhibits at the transcriptional level. ► DNA-binding mutant or TFIIB-binding mutant fails to inhibit. ► C-terminal aa 707 to 1116 are required for full inhibition. ► Inhibition requires the DNA-binding domain, TFIIB-binding domain, and C-terminus.

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Life Sciences Immunology and Microbiology Virology
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