The Epstein-Barr Virus (EBV) gN Homolog BLRF1 Encodes a 15-Kilodalton Glycoprotein That Cannot Be Authentically Processed unless It Is Coexpressed with the EBV gM Homolog BBRF3

ABSTRACT The Epstein-Barr virus (EBV) homolog of the conserved herpesvirus glycoprotein gN is predicted to be encoded by the BLRF1 open reading frame (ORF). Antipeptide antibody to a sequence corresponding to residues in the predicted BLRF1 ORF immunoprecipitated a doublet of approximately 8 kDa from cells expressing the BLRF1 ORF as a recombinant protein. In addition, four glycosylated proteins of 113, 84, 48, and 15 kDa could be immunoprecipitated from virus-producing cells by the same antibody. The 15-kDa species was the mature form of gN, which carried α2,6-sialic acid residues. The remaining glycoproteins which associated with gN were products of the BBRF3 ORF of EBV, which encodes the EBV gM homolog. The 8-kDa doublet seen in cells expressing recombinant gN comprised precursors of the mature 15-kDa gN. Coexpression of EBV gM with EBV gN was required for authentic processing of the 8-kDa forms to the 15-kDa form.

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Unexpected Absence of the Epstein-Barr Virus (EBV) lyLMP-1 Open Reading Frame in Tumor Virus Isolates: Lack of Correlation between Met129 Status and EBV Strain Identity

Journal of Virology ◽

10.1128/jvi.77.7.4415-4422.2003 ◽

2003 ◽

Vol 77 (7) ◽

pp. 4415-4422 ◽

Cited By ~ 9

Author(s):

Kimberly D. Erickson ◽

Christoph Berger ◽

William F. Coffin ◽

Edwin Schiff ◽

Dennis M. Walling ◽

...

Keyword(s):

Cell Lines ◽

Epstein Barr Virus ◽

Open Reading Frame ◽

Lytic Cycle ◽

Reading Frame ◽

Barr Virus ◽

Tumor Virus ◽

Epstein Barr ◽

Virus Isolates ◽

Codon 129

ABSTRACT The lytic cycle-associated lytic latent membrane protein-1 (lyLMP-1) of Epstein-Barr virus (EBV) is an amino-terminally truncated form of the oncogenic LMP-1. Although lyLMP-1 shares none of LMP-1's transforming and signal transducing activities, we recently reported that lyLMP-1 can negatively regulate LMP-1-stimulated NF-κB activation. The lyLMP-1 protein encoded by the B95-8 strain of EBV initiates from methionine 129 (Met129) of the LMP-1 open reading frame (ORF). The recent report that Met129 in the B95-8 LMP-1 ORF is not conserved in the Akata strain of EBV prompted us to screen a panel of EBV-positive cell lines for conservation of Met129 and lyLMP-1 expression. We found that 15 out of 16 tumor-associated virus isolates sequenced encoded an ATT or ACC codon in place of ATG in the LMP-1 ORF at position 129, and tumor cell lines harboring isolates lacking an ATG at codon 129 did not express the lyLMP-1 protein. In contrast, we found that EBV DNA from 22 out of 37 healthy seropositive donors retained the Met129 codon. Finally, the lyLMP-1 initiator occurs variably within distinct EBV strains and its presence cannot be predicted by EBV strain identity. Thus, Met129 is not peculiar to the B95-8 strain of EBV, but rather can be found in the background of several evolutionarily distinct EBV strains. Its absence from EBV isolates from tumors raises the possibility of selective pressure on Met129 in EBV-dependent tumors.

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Epstein–Barr Virus BALF0 and BALF1 Modulate Autophagy

Viruses ◽

10.3390/v11121099 ◽

2019 ◽

Vol 11 (12) ◽

pp. 1099

Author(s):

Zhouwulin Shao ◽

Chloé Borde ◽

Frédérique Quignon ◽

Alexandre Escargueil ◽

Vincent Maréchal

Keyword(s):

Cell Survival ◽

Epstein Barr Virus ◽

Viral Proteins ◽

Open Reading Frame ◽

Lytic Cycle ◽

Reading Frame ◽

Barr Virus ◽

Viral Particles ◽

Epstein Barr ◽

Catabolic Process

Autophagy is an essential catabolic process that degrades cytoplasmic components within the lysosome, therefore ensuring cell survival and homeostasis. A growing number of viruses, including members of the Herpesviridae family, have been shown to manipulate autophagy to facilitate their persistence or optimize their replication. Previous works showed that the Epstein–Barr virus (EBV), a human transforming gammaherpesvirus, hijacked autophagy during the lytic phase of its cycle, possibly to favor the formation of viral particles. However, the viral proteins that are responsible for an EBV-mediated subversion of the autophagy pathways remain to be characterized. Here we provide the first evidence that the BALF0/1 open reading frame encodes for two conserved proteins of the Bcl-2 family, BALF0 and BALF1, that are expressed during the early phase of the lytic cycle and can modulate autophagy. A putative LC3-interacting region (LIR) has been identified that is required both for BALF1 colocalization with autophagosomes and for its ability to stimulate autophagy.

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Establishment of a monkey kidney epithelial cell line with the BARF1 open reading frame from Epstein-Barr Virus

Oncogene ◽

10.1038/sj.onc.1201128 ◽

1997 ◽

Vol 14 (25) ◽

pp. 3073-3081 ◽

Cited By ~ 47

Author(s):

Ming Xin Wei ◽

Mireille de Turenne-Tessier ◽

Gisèle Decaussin ◽

Gérard Benet ◽

Tadamasa Ooka

Keyword(s):

Epithelial Cell ◽

Cell Line ◽

Epstein Barr Virus ◽

Open Reading Frame ◽

Epithelial Cell Line ◽

Reading Frame ◽

Barr Virus ◽

Kidney Epithelial Cell ◽

Kidney Epithelial Cell Line ◽

Epstein Barr

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Epstein-Barr Virus BamHI-A Rightward Transcript-Encoded RPMS Protein Interacts with the CBF1-Associated Corepressor CIR To Negatively Regulate the Activity of EBNA2 and NotchIC

Journal of Virology ◽

10.1128/jvi.75.6.2946-2956.2001 ◽

2001 ◽

Vol 75 (6) ◽

pp. 2946-2956 ◽

Cited By ~ 44

Author(s):

Jinxia Zhang ◽

Honglin Chen ◽

Gerry Weinmaster ◽

S. Diane Hayward

Keyword(s):

Cell Lines ◽

Epstein Barr Virus ◽

Intracellular Localization ◽

Open Reading Frame ◽

Negative Regulator ◽

Reading Frame ◽

Barr Virus ◽

Corepressor Complex ◽

Epstein Barr ◽

Two Hybrid

ABSTRACT The Epstein-Barr virus (EBV) BamHI-A rightward transcripts (BARTs) are expressed in all EBV-associated tumors as well as in latently infected B cells in vivo and cultured B-cell lines. One of the BART family transcripts contains an open reading frame, RPMS1, that encodes a nuclear protein termed RPMS. Reverse transcription-PCR analysis revealed that BART transcripts with the splicing pattern that generates the RPMS1 open reading frame are commonly expressed in EBV-positive lymphoblastoid cell lines and are also detected in Hodgkin's disease tissues. Experiments undertaken to determine the function of RPMS revealed that RPMS interacts with both CBF1 and components of the CBF1-associated corepressor complex. RPMS interaction with CBF1 was demonstrated in a glutathione S-transferase (GST) affinity assay and by the ability of RPMS to alter the intracellular localization of a mutant CBF1. A Gal4-RPMS fusion protein mediated transcriptional repression, suggesting an additional interaction between RPMS and corepressor proteins. GST affinity assays revealed interaction between RPMS and the corepressor Sin3A and CIR. The RPMS-CIR interaction was further substantiated in mammalian two-hybrid, coimmunoprecipitation, and colocalization experiments. RPMS has been shown to interfere with NotchIC and EBNA2 activation of CBF1-containing promoters in reporter assays. Consistent with this function, immunofluorescence assays performed on cotransfected cells showed that there was colocalization of RPMS with NotchIC and with EBNA2 in intranuclear punctate speckles. The effect of RPMS on NotchIC function was further examined in a muscle cell differentiation assay where RPMS was found to partially reverse NotchIC-mediated inhibition of differentiation. The mechanism of RPMS action was examined in cotransfection and mammalian two-hybrid assays. The results revealed that RPMS blocked relief of CBF1-mediated repression and interfered with SKIP-CIR interactions. We conclude that RPMS acts as a negative regulator of EBNA2 and Notch activity through its interactions with the CBF1-associated corepressor complex.

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