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Expression and localization of the Epstein-Barr virus-encoded protein kinase.
Gershburg, E; Marschall, M; Hong, K; Pagano, J S.
Affiliation
  • Gershburg E; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, CB no. 7295, Chapel Hill, NC 27599-7295, USA.
J Virol ; 78(22): 12140-6, 2004 Nov.
Article in En | MEDLINE | ID: mdl-15507600
ABSTRACT
The protein kinase (PK) encoded by the Epstein-Barr Virus (EBV) BGLF4 gene is the only EBV protein kinase. The expression pattern of EBV PK during the reactivation of the viral lytic cycle and the subcellular localization of the protein were analyzed with a polyclonal antiserum raised against a peptide corresponding to the N terminus of EBV PK. Based on previously published data (E. Gershburg and J. S. Pagano, J. Virol. 76998-1003, 2002) and the expression pattern described here, we conclude that EBV PK is an early protein that requires viral-DNA replication for maximum expression. By biochemical fractionation, the protein could be detected mainly in the nuclear fraction 4 h after viral reactivation in Akata cells. Nuclear localization could be visualized by indirect immunofluorescence in HeLa cells transiently expressing EBV BGLF4 in the absence of other viral products. Transient expression of 3'-terminal deletion mutants of EBV BGLF4 resulted in cytoplasmic localization, confirming the presence of a nuclear localization site in the C-terminal region of the protein. In contrast to the wild-type EBV PK, all of the mutants were unable to hyperphosphorylate EA-D during coexpression or to phosphorylate ganciclovir, as measured by an in-cell activity assay. Thus, the results demonstrate that the nuclear localization, as well as the kinase activity, of BGFL4 is dependent on an intact C-terminal region.
Subject(s)

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Viral Proteins / Protein Serine-Threonine Kinases / Herpesvirus 4, Human Limits: Humans Language: En Journal: J Virol Year: 2004 Document type: Article Affiliation country: Estados Unidos

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Viral Proteins / Protein Serine-Threonine Kinases / Herpesvirus 4, Human Limits: Humans Language: En Journal: J Virol Year: 2004 Document type: Article Affiliation country: Estados Unidos
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