scholarly journals Tumor Suppressor p53 Stimulates the Expression of Epstein-Barr Virus Latent Membrane Protein 1

2017 ◽  
Vol 91 (20) ◽  
Author(s):  
Qianli Wang ◽  
Amy Lingel ◽  
Vicki Geiser ◽  
Zachary Kwapnoski ◽  
Luwen Zhang
Keyword(s):  
Dna Damage ◽  
Tumor Suppressor ◽  
Epstein Barr Virus ◽  
Latent Membrane Protein ◽  
Latent Membrane Protein 1 ◽  
Tumor Suppressor P53 ◽  
Viral Oncogene ◽  
Barr Virus ◽  
Lmp1 Expression ◽  
Epstein Barr

ABSTRACT Epstein-Barr virus (EBV) is associated with multiple human malignancies. EBV latent membrane protein 1 (LMP1) is required for the efficient transformation of primary B lymphocytes in vitro and possibly in vivo. The tumor suppressor p53 plays a seminal role in cancer development. In some EBV-associated cancers, p53 tends to be wild type and overly expressed; however, the effects of p53 on LMP1 expression is not clear. We find LMP1 expression to be associated with p53 expression in EBV-transformed cells under physiological and DNA damaging conditions. DNA damage stimulates LMP1 expression, and p53 is required for the stimulation. Ectopic p53 stimulates endogenous LMP1 expression. Moreover, endogenous LMP1 blocks DNA damage-mediated apoptosis. Regarding the mechanism of p53-mediated LMP1 expression, we find that interferon regulatory factor 5 (IRF5), a direct target of p53, is associated with both p53 and LMP1. IRF5 binds to and activates a LMP1 promoter reporter construct. Ectopic IRF5 increases the expression of LMP1, while knockdown of IRF5 leads to reduction of LMP1. Furthermore, LMP1 blocks IRF5-mediated apoptosis in EBV-infected cells. All of the data suggest that cellular p53 stimulates viral LMP1 expression, and IRF5 may be one of the factors for p53-mediated LMP1 stimulation. LMP1 may subsequently block DNA damage- and IRF5-mediated apoptosis for the benefits of EBV. The mutual regulation between p53 and LMP1 may play an important role in EBV infection and latency and its related cancers. IMPORTANCE The tumor suppressor p53 is a critical cellular protein in response to various stresses and dictates cells for various responses, including apoptosis. This work suggests that an Epstein-Bar virus (EBV) principal viral oncogene is activated by cellular p53. The viral oncogene blocks p53-mediated adverse effects during viral infection and transformation. Therefore, the induction of the viral oncogene by p53 provides a means for the virus to cope with infection and DNA damage-mediated cellular stresses. This seems to be the first report that p53 activates a viral oncogene; therefore, the discovery would be interesting to a broad readership from the fields of oncology to virology.

scholarly journals Induction of Epstein-Barr Virus Latent Membrane Protein 1 by a Lytic Transactivator Rta

2004 ◽  
Vol 78 (23) ◽  
pp. 13028-13036 ◽  
Author(s):  
Yao Chang ◽  
Heng-Huan Lee ◽  
Shih-Shin Chang ◽  
Tsuey-Ying Hsu ◽  
Pei-Wen Wang ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Epstein Barr Virus ◽  
Latent Membrane Protein ◽  
Lytic Cycle ◽  
Immediate Early ◽  
Latent Membrane Protein 1 ◽  
Virus Reactivation ◽  
Barr Virus ◽  
Lmp1 Expression ◽  
Epstein Barr

ABSTRACT Latent membrane protein 1 (LMP1) of Epstein-Barr virus (EBV) is a transforming protein that affects multiple cell signaling pathways and contributes to EBV-associated oncogenesis. LMP1 can be expressed in some states of EBV latency, and significant induction of full-length LMP1 is also observed frequently during virus reactivation into the lytic cycle. It is still unknown how LMP1 expression is regulated during the lytic stage and whether any EBV lytic protein is involved in the induction of LMP1. In this study, we first identified that LMP1 expression is associated with the spontaneous virus reactivation in EBV-infected 293 cells and that its expression is a downstream event of the lytic cycle. We further found that LMP1 can be induced by ectopic expression of Rta, an EBV immediate-early lytic protein. The Rta-mediated LMP1 induction is independent of another immediate-early protein, Zta. Northern blotting and reverse transcription-PCR analysis revealed that Rta upregulates LMP1 at the RNA level. Reporter gene assays further demonstrated that Rta activates both the proximal and distal promoters of the LMP1 gene in EBV-negative cells. Both the amino and carboxyl termini of the Rta protein are required for the induction of LMP1. In addition, Rta transactivates LMP1 not only in epithelial cells but also in B-lymphoid cells. This study reveals a new mechanism to upregulate LMP1 expression, expanding the knowledge of LMP1 regulation in the EBV life cycle. Considering an equivalent case of Kaposi's sarcoma-associated herpesvirus, induction of a transforming membrane protein by a key lytic transactivator during virus reactivation is likely to be a conserved event for gammaherpesviruses.

scholarly journals Epstein-Barr Virus Selectively Deregulates DNA Damage Responses in Normal B Cells but Has No Detectable Effect on Regulation of the Tumor Suppressor p53

2006 ◽  
Vol 80 (24) ◽  
pp. 12408-12413 ◽  
Author(s):  
Jenny O'Nions ◽  
Abigail Turner ◽  
Richard Craig ◽  
Martin J. Allday
Keyword(s):  
Dna Damage ◽  
B Cells ◽  
Tumor Suppressor ◽  
Epstein Barr Virus ◽  
Detectable Effect ◽  
Tumor Suppressor P53 ◽  
Regulatory Pathways ◽  
Barr Virus ◽  
Dna Damage Responses ◽  
Epstein Barr

ABSTRACT To determine whether latent Epstein-Barr virus (EBV) modifies DNA damage responses in B lymphocytes, cells were treated with agents either producing DNA cross-links and adducts or generating double-strand breaks. The cyclin-dependent kinase inhibitor p21WAF1 accumulated in mitogen-stimulated primary B cells following exposure to all genotoxins tested. In contrast, when proliferation was EBV driven, p21WAF1 failed to accumulate after treatment with the DNA adduct-producing agents. The tumor suppressor p53 was stabilized and phosphorylated after all treatments, irrespective of whether latent EBV was present. This suggests that regulatory pathways upstream of p53 are unaffected by latent EBV but downstream effectors are altered if DNA adducts or distortions are involved.

scholarly journals Sequence Variations of Epstein-Barr Virus-Encoded Small Noncoding RNA and Latent Membrane Protein 1 in Hematologic Tumors in Northern China

Intervirology ◽  
2021 ◽  
Vol 64 (2) ◽  
pp. 69-80
Author(s):  
Hai-Yu Wang ◽  
Lingling Sun ◽  
Ping Li ◽  
Wen Liu ◽  
Zhong-Guang Zhang ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Nested Pcr ◽  
Noncoding Rna ◽  
Epstein Barr Virus ◽  
Northern China ◽  
Latent Membrane Protein ◽  
Latent Membrane Protein 1 ◽  
Small Noncoding Rna ◽  
Barr Virus ◽  
Epstein Barr

<b><i>Objective:</i></b> To investigate the relationship between hematologic tumors and Epstein-Barr virus (EBV)-encoded small noncoding RNA (EBER) variations as well as latent membrane protein 1 (LMP1) variations. <b><i>Methods:</i></b> Patients with leukemia and myelodysplastic syndrome (MDS) were selected as subjects. Genotypes 1/2 and genotypes F/f were analyzed using the nested PCR technology, while EBER and LMP1 subtypes were analyzed by the nested PCR and DNA sequencing. <b><i>Results:</i></b> Type 1 was more dominant than type 2, found in 59 out of 82 (72%) leukemia and in 31 out of 35 (88.6%) MDS, while type F was more prevalent than type f in leukemia (83/85, 97.6%) and MDS (29/31, 93.5%) samples. The distribution of EBV genotypes 1/2 was not significantly different among leukemia, MDS, and healthy donor groups, neither was that of EBV genotypes F/f. EB-6m prototype was the dominant subtype of EBER in leukemia and MDS (73.2% [30/41] and 83.3% [10/12], respectively). The frequency of EB-6m was lower than that of healthy people (96.7%, 89/92), and the difference was significant (<i>p</i> &#x3c; 0.05). China 1 subtype was the dominant subtype of LMP1 in leukemia and MDS (70% [28/40] and 90% [9/10], respectively), and there was no significant difference in the distribution of LMP1 subtypes among the 3 groups (<i>p</i> &#x3e; 0.05). <b><i>Conclusion:</i></b> The distribution of EBV 1/2, F/f, EBER, and LMP1 subtypes in leukemia and MDS was similar to that in the background population in Northern China, which means that these subtypes may be rather region-restricted but not associated with leukemia and MDS pathogenesis.

Epstein-Barr virus latent membrane protein 1 mRNA is expressed in a significant proportion of patients with chronic lymphocytic leukemia

Cancer ◽  
2010 ◽  
Vol 116 (4) ◽  
pp. 880-887 ◽  
Author(s):  
Jeffrey J. Tarrand ◽  
Michael J. Keating ◽  
Apostolia M. Tsimberidou ◽  
Susan O'Brien ◽  
Rocco P. LaSala ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Membrane Protein ◽  
Epstein Barr Virus ◽  
Significant Proportion ◽  
Latent Membrane Protein ◽  
Lymphocytic Leukemia ◽  
Latent Membrane Protein 1 ◽  
Barr Virus ◽  
Epstein Barr ◽  
Virus Latent Membrane Protein
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