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Transcriptional activation of Epstein-Barr virus BRLF1 by USF1 and Rta.
- Source :
-
The Journal of general virology [J Gen Virol] 2015 Sep; Vol. 96 (9), pp. 2855-2866. Date of Electronic Publication: 2015 Jun 30. - Publication Year :
- 2015
-
Abstract
- During its lytic cycle, Epstein-Barr virus (EBV) expresses Rta, a factor encoded by BRLF1 that activates the transcription of viral lytic genes. We found that upstream stimulating factor (USF) binds to E1, one of the five E boxes located at - 79 in the BRLF1 promoter (Rp), to activate BRLF1 transcription. Furthermore, Rta was shown to interact with USF1 in coimmunoprecipitation and glutathione S-transferase (GST)-pulldown assays, and confocal laser-scanning microscopy further confirmed that these two proteins colocalize in the nucleus. Rta was also found to bind with the E1 sequence in a biotin-labelled E1 probe, but only in the presence of USF1, suggesting that these two proteins likely form a complex on E1. We subsequently constructed p188mSZ, a reporter plasmid that contained the sequence from - 188 to +5 in Rp, within which the Sp1 site and Zta response element were mutated. In EBV-negative Akata cells cotransfected with p188mSZ and plasmids expressing USF1 and Rta, synergistic activation of Rp transcription was observed. However, after mutating the E1 sequence in p188mSZ, USF1 and Rta were no longer able to transactivate Rp, indicating that Rta autoregulates BRLF1 transcription via its interaction with USF1 on E1. This study showed that pUSF1 transfection after EBV lytic induction in P3HR1 cells increases Rta expression, indicating that USF1 activates Rta expression after the virus enters the lytic cycle. Together, these results reveal a novel mechanism by which USF interacts with Rta to promote viral lytic development, and provide additional insight into the viral-host interactions of EBV.
- Subjects :
- Base Sequence
Binding Sites
Epstein-Barr Virus Infections genetics
Epstein-Barr Virus Infections virology
Gene Expression Regulation, Viral
Herpesvirus 4, Human chemistry
Herpesvirus 4, Human metabolism
Host-Pathogen Interactions
Humans
Immediate-Early Proteins chemistry
Immediate-Early Proteins metabolism
Molecular Sequence Data
Promoter Regions, Genetic
Protein Binding
Trans-Activators chemistry
Upstream Stimulatory Factors genetics
Epstein-Barr Virus Infections metabolism
Herpesvirus 4, Human genetics
Immediate-Early Proteins genetics
Trans-Activators genetics
Trans-Activators metabolism
Transcriptional Activation
Upstream Stimulatory Factors metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1465-2099
- Volume :
- 96
- Issue :
- 9
- Database :
- MEDLINE
- Journal :
- The Journal of general virology
- Publication Type :
- Academic Journal
- Accession number :
- 26297580
- Full Text :
- https://doi.org/10.1099/jgv.0.000230