Viral proteins associated with the Epstein-Barr virus transactivator, ZEBRA.

Katz, David A.; Baumann, Raymond P.; Sun, Ren; Kolman, J L; Taylor, Naomi; Miller, George

doi:10.1073/pnas.89.1.378

Cited by 19 publications

(21 citation statements)

References 21 publications

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“…2A). After autoradiography of 35 S-labeled immunoprecipitates it was found that ZEBRA mutants that carried an alanine substitution at S186 were expressed to higher levels than wild-type ZEBRA (compare lanes 7 and 8 with lane 6). However, 32 P labeling indicated that mutations of S167 and S173 to alanine reduced but did not abolish the overall level of phosphorylation (compare lane 4 with lane 3).…”

Section: Ck2mentioning

confidence: 99%

“…As no lysine or arginine residues are present between S167 and S173, the two residues are located on the same tryptic peptide. This tryptic peptide can be detected in a peptide map of 35 Slabeled ZEBRA due to the presence of a cysteine residue at position 171. We compared the migration of 35 S-labeled tryptic peptides of Z(S186A) and Z(C171A/S186A) with phosphopeptides A and D, the phosphopeptides that disappeared when S167 and S173 were mutated to alanine (Fig.…”

Section: Ck2mentioning

confidence: 99%

“…The separated proteins were transferred to a nitrocellulose membrane. Rabbit polyclonal antibodies were used to detect ZEBRA (63), Rta (47), and BLRF2 (35). The SJ human serum was used to detect BFRF3 and EBNA1 (55).…”

Section: Eukaryotic Expression Vectors and Transient Transfectionsmentioning

confidence: 99%

“…Mutation of C171 to alanine resulted in the disappearance of a major 35 S spot that corresponds to the S167/C171/S173 tryptic peptide (Fig. 3B).…”

mentioning

confidence: 99%

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Phosphorylation of Epstein-Barr Virus ZEBRA Protein at Its Casein Kinase 2 Sites Mediates Its Ability To Repress Activation of a Viral Lytic Cycle Late Gene by Rta

El-Guindy¹,

Miller

2004

J Virol

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ZEBRA, a member of the bZIP family, serves as a master switch between latent and lytic cycle Epstein-Barr virus (EBV) gene expression. ZEBRA influences the activity of another viral transactivator, Rta, in a genespecific manner. Some early lytic cycle genes, such as BMRF1, are activated in synergy by ZEBRA and Rta. However, ZEBRA suppresses Rta's ability to activate a late gene, BLRF2. Here we show that this repressive activity is dependent on the phosphorylation state of ZEBRA. We find that two residues of ZEBRA, S167 and S173, that are phosphorylated by casein kinase 2 (CK2) in vitro are also phosphorylated in vivo. Inhibition of ZEBRA phosphorylation at the CK2 substrate motif, either by serine-to-alanine substitutions or by use of a specific inhibitor of CK2, abolished ZEBRA's capacity to repress Rta activation of the BLRF2 gene, but did not alter its ability to initiate the lytic cycle or to synergize with Rta in activation of the BMRF1 early-lytic-cycle gene. These studies illustrate how the phosphorylation state of a transcriptional activator can modulate its behavior as an activator or repressor of gene expression. Phosphorylation of ZEBRA at its CK2 sites is likely to play an essential role in proper temporal control of the EBV lytic life cycle.

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Section: Ck2mentioning

confidence: 99%

Section: Ck2mentioning

confidence: 99%

Section: Eukaryotic Expression Vectors and Transient Transfectionsmentioning

confidence: 99%

“…Mutation of C171 to alanine resulted in the disappearance of a major 35 S spot that corresponds to the S167/C171/S173 tryptic peptide (Fig. 3B).…”

mentioning

confidence: 99%

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Phosphorylation of Epstein-Barr Virus ZEBRA Protein at Its Casein Kinase 2 Sites Mediates Its Ability To Repress Activation of a Viral Lytic Cycle Late Gene by Rta

El-Guindy¹,

Miller

2004

J Virol

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“…Transcriptional activation of recombinant ori Lyt was utilized to drive a reporter construct in Raji cells underlying inducing culture conditions. BZLF 1 plays the key role in the transmission of inducing signals from the host cell towards the replicative activation of the viral genome [15,17,26]. Besides up-regulation of viral regulatory genes in a cascade-like manner, direct trans-activation of oriLyt by the BZLF 1 product was reported [7,13].…”

Section: Introductionmentioning

confidence: 99%

The lytic transition of Epstein-Barr virus is imitated by recombinant B-cells

Marschall

Alliger

Schwarzmann

et al. 1993

Archives of Virology

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Summary. Lytic transition of Epstein-Barr virus (EBV) is initiated by distinctimmediate early regulators of the viral cycle, in synchronization to temporary, permissive conditions during host cell differentiation. We developed eukaryotic vectors suitable to imitate the processes involved in lyric transition in cell culture systems. Two stable B cell lines were established: R59Z activator cells were used to induce lytic EBV expression in a constitutive manner by the production of the BZLF 1 trans-activator (Zta). R7-57 reporter cells, on the other hand, signaled induced activity of the lyric origin of EBV replication (ori Lyt). Different modes, like chemical induction, lyric superinfection with EBV and single gene trans-activation converted the recombinant ori Lyt element in R7-57 reporter cells. BZLF 1, transiently expressed in R7-57 reporter cells, was the only EBV trans-activator found, sufficient in inducing the viral lytic cycle. Basing on these experiments, trans-cellular activation of EBV was tested by cocultivation of BZLF 1-expressing R59Z activator cells with the R7-57 reporter line. No lyric effect on the reporter cells could be measured, neither by cocultivation of activator cells nor by coincubation of BZLF 1-containing cell lysates. Latency breaking activity, however, was transferred from activator to reporter cells when active, exogenous virus was added. The cell system described in these experiments provides a tool for the detection of EBV reactivation and demonstrates the potential of the lytic regulatory gene BZLF 1.

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Latency of Epstein-Barr virus is stabilized by antisense-mediated control of the viral immediate-early gene BZLF-1

Prang¹,

Wolf

Schwarzmann

1999

J. Med. Virol.

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The ability of the Epstein-Barr virus (EBV) to avoid lytic replication and to establish a latent infection in B-lymphocytes is fundamental for its lifelong persistence and the pathogenesis of various EBV-associated diseases. The viral immediate-early gene BZLF-1 plays a key role for the induction of lytic replication and its activity is strictly regulated on different levels of gene expression. Recently, it was demonstrated that BZLF-1 is also controlled by a posttranscriptional mechanism. Transient synthesis of a mutated competitor RNA saturated this mechanism and caused both expression of the BZLF-1 protein and the induction of lytic viral replication. Using short overlapping fragments of the competitor, it is shown that this control acts on the unspliced primary transcript. RT-PCR demonstrated unspliced BZLF-1 RNA in latently infected B-lymphocytes in the absence of BZLF-1 protein. Due to the complementarity of the gene BZLF-1 and the latency-associated gene EBNA-1 on the opposite strand of the genome, we propose an antisense-mediated mechanism. RNase protection assays demonstrated transcripts in antisense orientation to the BZLF-1 transcript during latency, which comprise a comparable constellation to other herpesviruses. A combined RNAse protection/RT-PCR assay detected the double-stranded hybrid RNA, consisting of the unspliced BZLF-1 transcript and a noncoding intron of the EBNA-1 gene. Binding of BZLF-1 transcripts is suggested to be an important backup control mechanism in addition to transcriptional regulation, stabilizing latency and preventing inappropriate lytic viral replication in vivo.

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Viral proteins associated with the Epstein-Barr virus transactivator, ZEBRA.

Cited by 19 publications

References 21 publications

Phosphorylation of Epstein-Barr Virus ZEBRA Protein at Its Casein Kinase 2 Sites Mediates Its Ability To Repress Activation of a Viral Lytic Cycle Late Gene by Rta

Phosphorylation of Epstein-Barr Virus ZEBRA Protein at Its Casein Kinase 2 Sites Mediates Its Ability To Repress Activation of a Viral Lytic Cycle Late Gene by Rta

The lytic transition of Epstein-Barr virus is imitated by recombinant B-cells

Latency of Epstein-Barr virus is stabilized by antisense-mediated control of the viral immediate-early gene BZLF-1

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