Abstract

Epstein-Barr virus nuclear antigen 2 (EBNA2), a protein involved in cell transformation, interferes with the cellular response to type I interferons (IFN-α/β). We investigated the function of conditionally expressed EBNA2 in the context of the IFN response in Burkitt's lymphoma cell lines. Expression of EBNA2 led to the transcriptional activation of both endogenous or transfected IFN-stimulated genes (ISGs), genes which contain within their promoters either the interferon-stimulated response element (ISRE) or the gamma interferon activation site (GAS). In search of a molecular mechanism for the transcriptional induction of ISGs, we observed an EBNA2-dependent synthesis of IFN-β mRNA at low levels and the secretion of low amounts of IFN. A transfected IFN-β promoter responded to EBNA2 activation, and a sequence closely resembling a RBP-Jκ binding site was pinpointed as a potential target of EBNA2 activity. EBNA2-dependent transcriptional induction of the IFN-β promoter occurred in EBV-negative Burkitt's lymphoma cells, indicating that other EBV genes were not required for the induction of IFN-β synthesis.