Mediation of Epstein-Barr virus EBNA2 transactivation by recombination signal-binding protein J kappa

The Epstein-Barr virus (EBV) transactivator protein, termed Epstein-Barr virus nuclear antigen 2 (EBNA2), plays a critical role in the regulation of latent viral transcription and in the immortalization of EBV-infected B cells. Unlike most transcription factors, EBNA2 does not bind directly to its cis-responsive DNA element but requires a cellular factor, termed C-promoter binding factor 1 (CBF1). Here, CBF1 was purified and was found to directly interact with EBNA2. CBF1 is identical to a protein thought to be involved in immunoglobulin gene rearrangement, RBPJ kappa. Contrary to previous reports, CBF1-RBPJ kappa did not bind to the recombination signal sequences but instead bound to sites in the EBV C-promoter and in the CD23 promoter.