Promoter Sequences Required for Reactivation of Epstein-Barr Virus from Latency

Abstract

A luciferase reporter system with stably transfected oriP plasmids in Akata Burkitt's lymphoma cells provides a quantitative assay for the BZLF1 Zp promoter in response to B-cell receptor (BCR) activation by cross-linking with anti-immunoglobulin. In this system, detailed kinetic studies of promoter activity are possible. Previously reported promoter elements upstream of ؊221 from the transcription start and the ZIIR sequence had little effect on the Zp promoter, but the ZI and ZIIIA elements were essential for early activation. The ZIIIB element mediates autoactivation. Mutation of the ZV repressor sequence greatly increased the induction of the promoter but did not make it constitutively active. Zp transcription in response to BCR cross-linking declined after a few hours; this decline was reduced and delayed by acyclovir or phosphonoacetic acid, indicating that viral DNA replication or a late viral gene can play a role in the switch off of the Zp promoter. Late expression of the LMP1 protein may account for this.

Virally targeted therapies for EBV-associated malignancies

“…In the case of the BZLF1 promoter (Zp), full activation Toxin expression specific to EBV-containing cells Figure 2 Latent viral promoters that require EBV-encoded gene products in trans, or the oriP replication origin that requires EBNA-1 in trans, can be used to produce cellular toxins specifically in EBV-positive cells requires both a 'ZII' motif (which binds CREB, ATF1, and a c-jun/ATF-2 heterodimer) and several different 'ZI' binding sites, which bind MEF2D as well as Sp1 and Sp3 (Flemington and Speck, 1990;Daibata et al, 1994;Speck et al, 1997;Wang et al, 1997;Adamson et al, 2000;Binne et al, 2002;Bryant and Farrell, 2002;Gruffat et al, 2002). Calcium-induced activation of MEF2D (mediated by calcineurin) and CREB (mediated by CaMKIV/GR) appears to be important for BZLF1 promoter activation following ligation of the B-cell receptor Liu et al, 1997).…”

Impaired Transporter Associated with Antigen Processing-Dependent Peptide Transport during Productive EBV Infection

“…1A). To this end, the pHEBO-Zp-luciferase reporter (22), kindly provided by Prof. P. J. Farrell, Ludwig Institute (Imperial College, London, U.K.), was digested with HindIII and SalI to remove the luciferase and promoter sequences, to be replaced with a rat CD2-GFP cassette that was PCR amplified from the pCD2-EGFP plasmid with 5Ј HindIII and 3Ј SalI restriction sites. A HindIII fragment containing a 5Ј regulatory sequence (from Ϫ400 to ϩ1) of BMRF1, was then inserted upstream of the rat CD2-GFP gene.…”

The BRRF1 Early Gene of Epstein-Barr Virus Encodes a Transcription Factor That Enhances Induction of Lytic Infection by BRLF1

“…To determine if Na itself is a transcriptional activator, we performed reporter gene assays with HeLa cells, using constructs in which either the BZLF1 (Zp) or BMRF1 (EAp) promoter was positioned upstream of the CAT gene. The Zp-CAT construct contains the BZLF1 promoter sequence from Ϫ221 to ϩ12, which has been shown to be sufficient for the induction of Zp activity by a variety of stimuli (4,17). Although the expression of Na had no effect on the activity of the construct driven by the BMRF1 (EAp) promoter, it increased the activity of the construct driven by Zp sevenfold (Fig.…”