File Download
  Links for fulltext
     (May Require Subscription)
Supplementary

Article: CCAAT/Enhancer Binding Protein α Binds to the Epstein-Barr Virus (EBV) ZTA Protein through Oligomeric Interactions and Contributes to Cooperative Transcriptional Activation of the ZTA Promoter through Direct Binding to the ZII and ZIIIB Motifs during Induction of the EBV Lytic Cycle

TitleCCAAT/Enhancer Binding Protein α Binds to the Epstein-Barr Virus (EBV) ZTA Protein through Oligomeric Interactions and Contributes to Cooperative Transcriptional Activation of the ZTA Promoter through Direct Binding to the ZII and ZIIIB Motifs during Induction of the EBV Lytic Cycle
Authors
Issue Date2004
PublisherAmerican Society for Microbiology. The Journal's web site is located at http://jvi.asm.org/
Citation
Journal Of Virology, 2004, v. 78 n. 9, p. 4847-4865 How to Cite?
AbstractThe Epstein-Barr virus (EBV)-encoded ZTA protein interacts strongly with and stabilizes the cellular CCAAT/enhancer binding protein α (C/EBPα), leading to the induction of p21-mediated G1 cell cycle arrest. Despite the strong interaction between these two basic leucine zipper (bZIP) family proteins, the ZTA and C/EBPα subunits do not heterodimerize, as indicated by an in vitro cross-linking assay with in vitro-cotranslated 35S-labeled C/EBPα and 35S-labeled ZTA protein. Instead, they evidently form a higher-order oligomeric complex that competes with C/EBPα binding but not with ZTA binding in electrophoretic mobility shift assays (EMSAs). Glutathione S-transferase affinity assays with mutant ZTA proteins revealed that the basic DNA binding domain and the key leucine zipper residues required for homodimerization are all required for the interaction with C/EBPα. ZTA is known to bind to two ZRE sites within the ZTA promoter and to positively autoregulate its own expression in transient cotransfection assays, but there is conflicting evidence about whether it does so in vivo. Examination of the proximal ZTA upstream promoter region by in vitro EMSA analysis revealed two high-affinity C/EBP binding sites (C-2 and C-3), which overlap the ZII and ZIIIB motifs, implicated as playing a key role in lytic cycle induction. A chromatin immunoprecipitation assay confirmed the in vivo binding of both endogenous C/EBPα and ZTA protein to the ZTA promoter after lytic cycle induction but not during the latent state in EBV-infected Akata cells. Reporter assays revealed that cotransfected C/EBPα activated the ZTA promoter even more effectively than cotransfected ZTA. However, synergistic activation of the ZTA promoter was not observed when ZTA and C/EBPα were cotransfected together in either HeLa or DG75 cells. Mutagenesis of either the ZII or the ZIlIB sites in the ZTA promoter strongly reduced C/EBPα transactivation, suggesting that these sites act cooperatively. Furthermore, the introduction of exogenous C/EBPα into EBV-infected HeLa-BX1 cells induced endogenous ZTA mRNA and protein expression, as demonstrated by both reverse transcription-PCR and immunoblotting assays. Finally, double-label immunofluorescence assays suggested that EAD protein expression was activated even better than ZTA expression in latently infected C/EBPα-transfected Akata cells, perhaps because of the presence of a strong B-cell-specific repressed chromatin conformation on the ZTA promoter itself during EBV latency.
Persistent Identifierhttp://hdl.handle.net/10722/49251
ISSN
2015 Impact Factor: 4.606
2015 SCImago Journal Rankings: 3.347
PubMed Central ID
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorWu, FYen_HK
dc.contributor.authorWang, SEen_HK
dc.contributor.authorChen, Hen_HK
dc.contributor.authorWang, Len_HK
dc.contributor.authorHayward, SDen_HK
dc.contributor.authorHayward, GSen_HK
dc.date.accessioned2008-06-12T06:37:36Z-
dc.date.available2008-06-12T06:37:36Z-
dc.date.issued2004en_HK
dc.identifier.citationJournal Of Virology, 2004, v. 78 n. 9, p. 4847-4865en_HK
dc.identifier.issn0022-538Xen_HK
dc.identifier.urihttp://hdl.handle.net/10722/49251-
dc.description.abstractThe Epstein-Barr virus (EBV)-encoded ZTA protein interacts strongly with and stabilizes the cellular CCAAT/enhancer binding protein α (C/EBPα), leading to the induction of p21-mediated G1 cell cycle arrest. Despite the strong interaction between these two basic leucine zipper (bZIP) family proteins, the ZTA and C/EBPα subunits do not heterodimerize, as indicated by an in vitro cross-linking assay with in vitro-cotranslated 35S-labeled C/EBPα and 35S-labeled ZTA protein. Instead, they evidently form a higher-order oligomeric complex that competes with C/EBPα binding but not with ZTA binding in electrophoretic mobility shift assays (EMSAs). Glutathione S-transferase affinity assays with mutant ZTA proteins revealed that the basic DNA binding domain and the key leucine zipper residues required for homodimerization are all required for the interaction with C/EBPα. ZTA is known to bind to two ZRE sites within the ZTA promoter and to positively autoregulate its own expression in transient cotransfection assays, but there is conflicting evidence about whether it does so in vivo. Examination of the proximal ZTA upstream promoter region by in vitro EMSA analysis revealed two high-affinity C/EBP binding sites (C-2 and C-3), which overlap the ZII and ZIIIB motifs, implicated as playing a key role in lytic cycle induction. A chromatin immunoprecipitation assay confirmed the in vivo binding of both endogenous C/EBPα and ZTA protein to the ZTA promoter after lytic cycle induction but not during the latent state in EBV-infected Akata cells. Reporter assays revealed that cotransfected C/EBPα activated the ZTA promoter even more effectively than cotransfected ZTA. However, synergistic activation of the ZTA promoter was not observed when ZTA and C/EBPα were cotransfected together in either HeLa or DG75 cells. Mutagenesis of either the ZII or the ZIlIB sites in the ZTA promoter strongly reduced C/EBPα transactivation, suggesting that these sites act cooperatively. Furthermore, the introduction of exogenous C/EBPα into EBV-infected HeLa-BX1 cells induced endogenous ZTA mRNA and protein expression, as demonstrated by both reverse transcription-PCR and immunoblotting assays. Finally, double-label immunofluorescence assays suggested that EAD protein expression was activated even better than ZTA expression in latently infected C/EBPα-transfected Akata cells, perhaps because of the presence of a strong B-cell-specific repressed chromatin conformation on the ZTA promoter itself during EBV latency.en_HK
dc.format.extent386 bytes-
dc.format.mimetypetext/html-
dc.languageengen_HK
dc.publisherAmerican Society for Microbiology. The Journal's web site is located at http://jvi.asm.org/en_HK
dc.relation.ispartofJournal of Virologyen_HK
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.rightsJournal of Virology. Copyright © American Society for Microbiology.en_HK
dc.rightsCopyright © American Society for Microbiology, Journal of Virology, 2004, v. 78 n. 9, p. 4847-4865en_HK
dc.subject.meshCCAAT-Enhancer-Binding Protein-alpha - metabolismen_HK
dc.subject.meshDNA-Binding Proteins - chemistry - genetics - metabolismen_HK
dc.subject.meshPromoter Regions (Genetics) - physiologyen_HK
dc.subject.meshTrans-Activation (Genetics)en_HK
dc.subject.meshTrans-Activators - chemistry - genetics - metabolismen_HK
dc.titleCCAAT/Enhancer Binding Protein α Binds to the Epstein-Barr Virus (EBV) ZTA Protein through Oligomeric Interactions and Contributes to Cooperative Transcriptional Activation of the ZTA Promoter through Direct Binding to the ZII and ZIIIB Motifs during Induction of the EBV Lytic Cycleen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0022-538X&volume=78&issue=9&spage=4847&epage=4865&date=2004&atitle=CCAAT/enhancer+binding+protein+α+binds+to+the+Epstein-Barr+virus(EBV)+ZTA+protein+through+oligomeric+interactions+and+contributes+to+cooperative+transcriptional+activation+of+the+ZTA+promoter+through+direct+binding+to+the+ZII+and+ZIIIB+motifs+during+inducen_HK
dc.identifier.emailChen, H:hlchen@hkucc.hku.hken_HK
dc.identifier.authorityChen, H=rp00383en_HK
dc.description.naturepublished_or_final_versionen_HK
dc.identifier.doi10.1128/JVI.78.9.4847-4865.2004en_HK
dc.identifier.pmid15078966-
dc.identifier.pmcidPMC387681en_HK
dc.identifier.scopuseid_2-s2.0-4344575045en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-4344575045&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume78en_HK
dc.identifier.issue9en_HK
dc.identifier.spage4847en_HK
dc.identifier.epage4865en_HK
dc.identifier.isiWOS:000220880200048-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridWu, FY=36991458700en_HK
dc.identifier.scopusauthoridWang, SE=8765314100en_HK
dc.identifier.scopusauthoridChen, H=26643315400en_HK
dc.identifier.scopusauthoridWang, L=8435948100en_HK
dc.identifier.scopusauthoridHayward, SD=7102776214en_HK
dc.identifier.scopusauthoridHayward, GS=7101602499en_HK

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats