File Download

There are no files associated with this item.

  Links for fulltext
     (May Require Subscription)
Supplementary

Article: A positive autoregulatory loop of LMP1 expression and STAT activation in epithelial cells latently infected with Epstein-Barr virus

TitleA positive autoregulatory loop of LMP1 expression and STAT activation in epithelial cells latently infected with Epstein-Barr virus
Authors
Issue Date2003
PublisherAmerican Society for Microbiology. The Journal's web site is located at http://jvi.asm.org/
Citation
Journal Of Virology, 2003, v. 77 n. 7, p. 4139-4148 How to Cite?
AbstractSTAT3 and STAT5 are constitutively activated and nuclear in nasopharyngeal carcinoma (NPC) cells. In normal signaling, STATs are only transiently activated. To investigate whether Epstein-Barr virus (EBV), and in particular the protein LMP1, contributes to sustained STAT phosphorylation and activation in epithelial cells, we examined STAT activity in two sets of paired cell lines, HeLa, an EBV-converted HeLa cell line, HeLa-Bx1, the NPC-derived cell line CNE2-LNSX, and an LMP1-expressing derivative, CNE2-LMP1. EBV infection was associated with a significant increase in the tyrosine-phosphorylated forms of STAT3 and STAT5 in HeLa-Bx1 cells. This effect correlated with LMP1 expression, since phosphorylated STAT3 and STAT5 levels were also increased in CNE2-LMP1 cells relative to the control CNE2-LNSX cells. No change was observed in STAT1 or STAT6 phosphorylation in these cell lines, nor was there a significant change in the levels of total STAT3, STAT5, STAT1, or STAT6 protein. Tyrosine phosphorylation allows the normally cytoplasmic STAT proteins to enter the nucleus and bind to their recognition sequences in responsive promoters. The ability of LMP1 to activate STAT3 was further established by immunofluorescence assays in which coexpression of LMP1 in transfected cells was sufficient to mediate nuclear relocalization of Flag-STAT3 and by an electrophoretic mobility shift assay which showed that LMP1 expression in CNE2-LNSX cells was associated with increased endogenous STAT3 DNA binding activity. In addition, the activity of a downstream target of STAT3, c-Myc, was upregulated in HeLa-Bx1 and CNE2-LMP1 cells. A linkage was established between interleukin-6 (IL-6)- and LMP1-mediated STAT3 activation. Treatment with IL-6 increased phosphorylated STAT3 levels in CNE2-LNSX cells, and conversely, treatment of CNE2-LMP1 cells with IL-6 neutralizing antibody ablated STAT3 activation and c-Myc upregulation. The previous observation that STAT3 activated the LMP1 terminal repeat promoter in reporter assays was extended to show upregulated expression of endogenous LMP1 mRNA and protein in HeLa-Bx1 cells transfected with a constitutively activated STAT3. A model is proposed in which EBV infection of an epithelial cell containing activated STATs would permit LMP1 expression. This in turn would establish a positive feedback loop of IL-6-induced STAT activation, LMP1 and Qp-EBNA1 expression, and viral genome persistence.
Persistent Identifierhttp://hdl.handle.net/10722/157353
ISSN
2015 Impact Factor: 4.606
2015 SCImago Journal Rankings: 3.347
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorChen, Hen_US
dc.contributor.authorHuttFletcher, Len_US
dc.contributor.authorCao, Len_US
dc.contributor.authorHayward, SDen_US
dc.date.accessioned2012-08-08T08:49:09Z-
dc.date.available2012-08-08T08:49:09Z-
dc.date.issued2003en_US
dc.identifier.citationJournal Of Virology, 2003, v. 77 n. 7, p. 4139-4148en_US
dc.identifier.issn0022-538Xen_US
dc.identifier.urihttp://hdl.handle.net/10722/157353-
dc.description.abstractSTAT3 and STAT5 are constitutively activated and nuclear in nasopharyngeal carcinoma (NPC) cells. In normal signaling, STATs are only transiently activated. To investigate whether Epstein-Barr virus (EBV), and in particular the protein LMP1, contributes to sustained STAT phosphorylation and activation in epithelial cells, we examined STAT activity in two sets of paired cell lines, HeLa, an EBV-converted HeLa cell line, HeLa-Bx1, the NPC-derived cell line CNE2-LNSX, and an LMP1-expressing derivative, CNE2-LMP1. EBV infection was associated with a significant increase in the tyrosine-phosphorylated forms of STAT3 and STAT5 in HeLa-Bx1 cells. This effect correlated with LMP1 expression, since phosphorylated STAT3 and STAT5 levels were also increased in CNE2-LMP1 cells relative to the control CNE2-LNSX cells. No change was observed in STAT1 or STAT6 phosphorylation in these cell lines, nor was there a significant change in the levels of total STAT3, STAT5, STAT1, or STAT6 protein. Tyrosine phosphorylation allows the normally cytoplasmic STAT proteins to enter the nucleus and bind to their recognition sequences in responsive promoters. The ability of LMP1 to activate STAT3 was further established by immunofluorescence assays in which coexpression of LMP1 in transfected cells was sufficient to mediate nuclear relocalization of Flag-STAT3 and by an electrophoretic mobility shift assay which showed that LMP1 expression in CNE2-LNSX cells was associated with increased endogenous STAT3 DNA binding activity. In addition, the activity of a downstream target of STAT3, c-Myc, was upregulated in HeLa-Bx1 and CNE2-LMP1 cells. A linkage was established between interleukin-6 (IL-6)- and LMP1-mediated STAT3 activation. Treatment with IL-6 increased phosphorylated STAT3 levels in CNE2-LNSX cells, and conversely, treatment of CNE2-LMP1 cells with IL-6 neutralizing antibody ablated STAT3 activation and c-Myc upregulation. The previous observation that STAT3 activated the LMP1 terminal repeat promoter in reporter assays was extended to show upregulated expression of endogenous LMP1 mRNA and protein in HeLa-Bx1 cells transfected with a constitutively activated STAT3. A model is proposed in which EBV infection of an epithelial cell containing activated STATs would permit LMP1 expression. This in turn would establish a positive feedback loop of IL-6-induced STAT activation, LMP1 and Qp-EBNA1 expression, and viral genome persistence.en_US
dc.languageengen_US
dc.publisherAmerican Society for Microbiology. The Journal's web site is located at http://jvi.asm.org/en_US
dc.relation.ispartofJournal of Virologyen_US
dc.subject.meshActive Transport, Cell Nucleusen_US
dc.subject.meshCell Lineen_US
dc.subject.meshDna-Binding Proteins - Genetics - Metabolismen_US
dc.subject.meshEpithelial Cells - Metabolism - Virologyen_US
dc.subject.meshFeedbacken_US
dc.subject.meshGene Expression Regulation, Viralen_US
dc.subject.meshGenes, Viralen_US
dc.subject.meshHela Cellsen_US
dc.subject.meshHerpesvirus 4, Human - Genetics - Metabolism - Pathogenicityen_US
dc.subject.meshHomeostasisen_US
dc.subject.meshHumansen_US
dc.subject.meshInterleukin-6 - Antagonists & Inhibitors - Metabolismen_US
dc.subject.meshMilk Proteinsen_US
dc.subject.meshModels, Biologicalen_US
dc.subject.meshPhosphorylationen_US
dc.subject.meshRecombinant Proteins - Metabolismen_US
dc.subject.meshStat3 Transcription Factoren_US
dc.subject.meshStat5 Transcription Factoren_US
dc.subject.meshSignal Transductionen_US
dc.subject.meshTrans-Activators - Genetics - Metabolismen_US
dc.subject.meshTransfectionen_US
dc.subject.meshViral Matrix Proteins - Genetics - Metabolismen_US
dc.titleA positive autoregulatory loop of LMP1 expression and STAT activation in epithelial cells latently infected with Epstein-Barr virusen_US
dc.typeArticleen_US
dc.identifier.emailChen, H:hlchen@hkucc.hku.hken_US
dc.identifier.authorityChen, H=rp00383en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1128/JVI.77.7.4139-4148.2003en_US
dc.identifier.pmid12634372-
dc.identifier.scopuseid_2-s2.0-0037378534en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0037378534&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume77en_US
dc.identifier.issue7en_US
dc.identifier.spage4139en_US
dc.identifier.epage4148en_US
dc.identifier.isiWOS:000181677900024-
dc.publisher.placeUnited Statesen_US
dc.identifier.scopusauthoridChen, H=26643315400en_US
dc.identifier.scopusauthoridHuttFletcher, L=7004909823en_US
dc.identifier.scopusauthoridCao, L=7401637818en_US
dc.identifier.scopusauthoridHayward, SD=7102776214en_US

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats