scholarly journals The split Renilla luciferase complementation assay is useful for identifying the interaction of Epstein-Barr virus protein kinase BGLF4 and a heat shock protein Hsp90

2016 ◽  
Vol 60 (01) ◽  
pp. 62-70 ◽  
Author(s):  
J. Wang ◽  
W. Guo ◽  
C. Long ◽  
H. Zhou ◽  
H. Wang ◽  
...  
Keyword(s):  
Heat Shock ◽  
Protein Kinase ◽  
Heat Shock Protein ◽  
Epstein Barr Virus ◽  
Renilla Luciferase ◽  
Virus Protein ◽  
Complementation Assay ◽  
Barr Virus ◽  
Epstein Barr

scholarly journals The Epstein-Barr Virus Protein Kinase BGLF4 and the Exonuclease BGLF5 Have Opposite Effects on the Regulation of Viral Protein Production

2009 ◽  
Vol 83 (21) ◽  
pp. 10877-10891 ◽  
Author(s):  
Regina Feederle ◽  
Anja M. Mehl-Lautscham ◽  
Helmut Bannert ◽  
Henri-Jacques Delecluse
Keyword(s):  
Protein Kinase ◽  
Viral Protein ◽  
Epstein Barr Virus ◽  
Protein Production ◽  
Opposite Effect ◽  
Viral Gene ◽  
Virus Protein ◽  
Barr Virus ◽  
Viral Genes ◽  
Epstein Barr

ABSTRACT The Epstein-Barr virus BGLF4 and BGLF5 genes encode a protein kinase and an alkaline exonuclease, respectively. Both proteins were previously found to regulate multiple steps of virus replication, including lytic DNA replication and primary egress. However, while inactivation of BGLF4 led to the downregulation of several viral proteins, the absence of BGLF5 had the opposite effect. Using recombinant viruses that lack both viral enzymes, we confirm and extend these initial observations, e.g., by showing that both BGLF4 and BGLF5 are required for proper phosphorylation of the DNA polymerase processivity factor BMRF1. We further found that neither BGLF4 nor BGLF5 is required for baseline viral protein production. Complementation with BGLF5 downregulated mRNA levels and translation of numerous viral genes, though to various degrees, whereas BGLF4 had the opposite effect. BGLF4 and BGLF5 influences on viral expression were most pronounced for BFRF1 and BFLF2, two proteins essential for nuclear egress. For most viral genes studied, cotransfection of BGLF4 and BGLF5 had only a marginal influence on their expression patterns, showing that BGLF4 antagonizes BGLF5-mediated viral gene shutoff. To be able to exert its functions on viral gene expression, BGLF4 must be able to escape BGLF5's shutoff activities. Indeed, we found that BGLF5 stimulated the BGLF4 gene's transcription through an as yet uncharacterized molecular mechanism. The BGLF4/BGLF5 enzyme pair builds a regulatory loop that allows fine-tuning of virus protein production, which is required for efficient viral replication.

scholarly journals Epstein-Barr Virus Protein Kinase BGLF4 Is a Virion Tegument Protein That Dissociates from Virions in a Phosphorylation-Dependent Process and Phosphorylates the Viral Immediate-Early Protein BZLF1

2006 ◽  
Vol 80 (11) ◽  
pp. 5125-5134 ◽  
Author(s):  
Risa Asai ◽  
Ai Kato ◽  
Kentaro Kato ◽  
Mikiko Kanamori-Koyama ◽  
Ken Sugimoto ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Epstein Barr Virus ◽  
Tegument Protein ◽  
Virus Protein ◽  
Barr Virus ◽  
Early Protein ◽  
Dependent Process ◽  
Epstein Barr

ABSTRACT Epstein-Barr virus (EBV) BGLF4 is a viral protein kinase that is expressed in the lytic phase of infection and is packaged in virions. We report here that BGLF4 is a tegument protein that dissociates from the virion in a phosphorylation-dependent process. We also present evidence that BGLF4 interacts with and phosphorylates BZLF1, a key viral regulator of lytic infection. These conclusions are based on the following observations. (i) In in vitro tegument release assays, a significant fraction of BGLF4 was released from virions in the presence of physiological NaCl concentrations. (ii) Addition of physiological concentrations of ATP and MgCl2 to virions enhanced BGLF4 release, but phosphatase treatment of virions significantly reduced BGLF4 release. (iii) A recombinant protein containing a domain of BZLF1 was specifically phosphorylated by purified recombinant BGLF4 in vitro, and BGLF4 altered BZLF1 posttranslational modification in vivo. (iv) BZLF1 was specifically coimmunoprecipitated with BGLF4 in 12-O-tetradecanoylphorbol-13-acetate-treated B95-8 cells and in COS-1 cells transiently expressing both of these viral proteins. (v) BGLF4 and BZLF1 were colocalized in intranuclear globular structures, resembling the viral replication compartment, in Akata cells treated with anti-human immunoglobulin G. Our results suggest that BGLF4 functions not only in lytically infected cells by phosphorylating viral and cellular targets but also immediately after viral penetration like other herpesvirus tegument proteins.

scholarly journals Hyperphosphorylation of EBNA2 by Epstein-Barr Virus Protein Kinase Suppresses Transactivation of the LMP1 Promoter

2005 ◽  
Vol 79 (9) ◽  
pp. 5880-5885 ◽  
Author(s):  
Wei Yue ◽  
Edward Gershburg ◽  
Joseph S. Pagano
Keyword(s):  
Protein Kinase ◽  
B Lymphocytes ◽  
Epstein Barr Virus ◽  
Lytic Cycle ◽  
Nuclear Antigen ◽  
Virus Protein ◽  
Protein Levels ◽  
Barr Virus ◽  
Latently Infected ◽  
Epstein Barr

ABSTRACT The Epstein-Barr virus (EBV) BGLF4 gene encodes a serine/threonine protein kinase (PK) that is expressed in the cytolytic cycle. EBV nuclear antigen 2 (EBNA2) is a key latency gene essential for immortalization of B lymphocytes and transactivation of viral and cellular promoters. Here we report that EBV PK phosphorylates EBNA2 at Ser-243 and that these two proteins physically associate. PK suppresses EBNA2's ability to transactivate the LMP1 promoter, and Ser-243 of EBNA2 is involved in this suppression. Moreover, EBNA2 is hyperphosphorylated during EBV reactivation in latently infected B cells, which is associated with decreased LMP1 protein levels. This is the first report about the effect of EBV PK on the function of one of its target proteins and regulation of EBNA2 phosphorylation during the EBV lytic cycle.

scholarly journals Effects of Maribavir and Selected Indolocarbazoles on Epstein-Barr Virus Protein Kinase BGLF4 and on Viral Lytic Replication

2004 ◽  
Vol 48 (5) ◽  
pp. 1900-1903 ◽  
Author(s):  
Edward Gershburg ◽  
Ke Hong ◽  
Joseph S. Pagano
Keyword(s):  
Protein Kinase ◽  
Dna Synthesis ◽  
Human Cytomegalovirus ◽  
Epstein Barr Virus ◽  
Lytic Replication ◽  
Virus Protein ◽  
Barr Virus ◽  
Ebv Dna ◽  
Epstein Barr

ABSTRACT The human cytomegalovirus (HCMV) homolog of the Epstein-Barr virus (EBV) protein kinase (PK), UL97, is inhibited by maribavir (1263W94) and selected indolocarbazoles. Here we show that only one of these indolocarbazoles (K252a), but not maribavir, inhibits autophosphorylation of the EBV PK, BGLF4. However, maribavir and another indolocarbazole, NGIC-I, do inhibit EBV DNA synthesis, suggesting that although these last compounds inhibit both HCMV and EBV, they seem to operate through differ-ent pathways.

scholarly journals Protein Array Identification of Substrates of the Epstein-Barr Virus Protein Kinase BGLF4

2009 ◽  
Vol 83 (10) ◽  
pp. 5219-5231 ◽  
Author(s):  
Jian Zhu ◽  
Gangling Liao ◽  
Liang Shan ◽  
Jun Zhang ◽  
Mei-Ru Chen ◽  
...  
Keyword(s):  
Dna Replication ◽  
Protein Kinase ◽  
Epstein Barr Virus ◽  
Protein Array ◽  
Lytic Cycle ◽  
Virus Protein ◽  
Barr Virus ◽  
Epstein Barr ◽  
Lytic Dna Replication ◽  
In Cells

ABSTRACT A conserved family of herpesvirus protein kinases plays a crucial role in herpesvirus DNA replication and virion production. However, despite the fact that these kinases are potential therapeutic targets, no systematic studies have been performed to identify their substrates. We generated an Epstein-Barr virus (EBV) protein array to evaluate the targets of the EBV protein kinase BGLF4. Multiple proteins involved in EBV lytic DNA replication and virion assembly were identified as previously unrecognized substrates for BGLF4, illustrating the broad role played by this protein kinase. Approximately half of the BGLF4 targets were also in vitro substrates for the cellular kinase CDK1/cyclin B. Unexpectedly, EBNA1 was identified as a substrate and binding partner of BGLF4. EBNA1 is essential for replication and maintenance of the episomal EBV genome during latency. BGLF4 did not prevent EBNA1 binding to sites in the EBV latency origin of replication, oriP. Rather, we found that BGLF4 was recruited by EBNA1 to oriP in cells transfected with an oriP vector and BGLF4 and in lytically induced EBV-positive Akata cells. In cells transfected with an oriP vector, the presence of BGLF4 led to more rapid loss of the episomal DNA, and this was dependent on BGLF4 kinase activity. Similarly, expression of doxycycline-inducible BGLF4 in Akata cells led to a reduction in episomal EBV genomes. We propose that BGLF4 contributes to effective EBV lytic cycle progression, not only through phosphorylation of EBV lytic DNA replication and virion proteins, but also by interfering with the EBNA1 replication function.

scholarly journals Efficient production of infectious viruses requires enzymatic activity of Epstein-Barr virus protein kinase

Virology ◽  
2009 ◽  
Vol 389 (1-2) ◽  
pp. 75-81 ◽  
Author(s):  
Takayuki Murata ◽  
Hiroki Isomura ◽  
Yoriko Yamashita ◽  
Shigenori Toyama ◽  
Yoshitaka Sato ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Enzymatic Activity ◽  
Epstein Barr Virus ◽  
Virus Protein ◽  
Efficient Production ◽  
Barr Virus ◽  
Epstein Barr

scholarly journals Phosphorylation of p27Kip1by Epstein-Barr Virus Protein Kinase Induces Its Degradation through SCFSkp2Ubiquitin Ligase Actions during Viral Lytic Replication

2009 ◽  
Vol 284 (28) ◽  
pp. 18923-18931 ◽  
Author(s):  
Satoko Iwahori ◽  
Takayuki Murata ◽  
Ayumi Kudoh ◽  
Yoshitaka Sato ◽  
Sanae Nakayama ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Epstein Barr Virus ◽  
Lytic Replication ◽  
Virus Protein ◽  
Barr Virus ◽  
Epstein Barr

scholarly journals SUMO Binding by the Epstein-Barr Virus Protein Kinase BGLF4 Is Crucial for BGLF4 Function

2012 ◽  
Vol 86 (10) ◽  
pp. 5412-5421 ◽  
Author(s):  
R. Li ◽  
L. Wang ◽  
G. Liao ◽  
C. M. Guzzo ◽  
M. J. Matunis ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Epstein Barr Virus ◽  
Virus Protein ◽  
Barr Virus ◽  
Epstein Barr
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