The Epstein-Barr virus nuclear antigen 2 interacts with an EBNA2 responsive cis-element of the terminal protein 1 gene promoter.

Abstract

The Epstein‐Barr virus protein EBNA2 acts as a transcriptional activator of cellular and viral genes and plays a crucial role in the immortalization of human primary B‐cells by EBV. We have shown previously that EBNA2 transactivates the promoters of the latent membrane antigens LMP, TP1 and TP2. The promoter of the TP1 gene was chosen as a model system to study the molecular mechanism of EBNA2 mediated transactivation. To identify an EBNA2 dependent cis‐acting element, various TP1 promoter‐reporter gene constructs were transfected in the absence and presence of an EBNA2 expression vector into the established B‐cell line BL41‐P3HR1. We were able to delineate an 81 bp EBNA2 responsive region between −258 and −177 relative to the TP1 RNA start site. The element worked in either orientation and could mediate EBNA2 dependent transactivation on a heterologous promoter. Electrophoretic mobility shift assays revealed three specific protein‐DNA complexes formed with sequences of the EBNA2 responsive element. Two of these were not cell type specific, but the third was detected only in EBNA2 positive cell extracts. Gel‐shift analysis in the presence of EBNA2 specific monoclonal antibodies revealed that EBNA2 is a component of the third complex. Thus, these experiments demonstrate that EBNA2 interacts with an EBNA2 responsive cis‐element of the TP1 promoter.

Epstein--Barr virus nuclear antigen 2 (EBNA2)-oestrogen receptor fusion proteins complement the EBNA2-deficient Epstein--Barr virus strain P3HR1 in transformation of primary B cells but suppress growth of human B cell lymphoma lines

“…For construction of 294-6/C and 294-6/N pM780-28 (Polack et al, 1984) was used as a vector regenerating EBV coordinates 39018 54364. The LMP1 and TP1 and TP2 promoter luciferase indicator plasmids have been described before Zimber-Strobl et al, 1993).…”

“…ER/EBNA2 expression plasmid (p554-4) was transfected in B lymphoma cell lines by electroporation as described before (Zimber-Strobl et al, 1993). Two days after transfection G418 (BRL) was added to a final concentration of 12501ag/ml (HH514 cells, BL41/P3HRI and BJAB/P3HR1 convertants) or 800 lag/ml (BL41 and BJAB) to the culture medium.…”

IL-21 imposes a type II EBV gene expression on type III and type I B cells by the repression of C- and activation of LMP-1-promoter

“…The molecular mechanisms responsible for the expression of LMP-1 in type II latency (EBNA-2-independent LMP-1 expression) are only partially known. EBNA-2 is also instrumental in the activation of C-and LMP-2-promoters in type III latent cells (13). LMP-1 can be expressed from two alternative promoters: the EBNA-2-responsive ED-L1 or the promoter located in the first terminal repeat (TR-promoter) (14).…”

Epstein-barr virus immortalization and latency

“…EBNA2-responsive elements in the promoters of the cellular CD23 gene, the viral EBNA Cp promoter and the viral promoter for the LMP1 gene have been mapped. (71,76,89,129,241,260). EBNA2 does not, however, directly interact with DNA.…”