MEDIATION OF EPSTEIN-BARR-VIRUS EBNA2 TRANSACTIVATION BY RECOMBINATION SIGNAL-BINDING PROTEIN J(K)

The Epstein-Barr virus (EBV) transactivator protein, termed Epstein-Ba rr virus nuclear antigen 2 (EBNA2), plays a critical role in the regul ation of latent viral transcription and in the immortalization of EBV- infected B cells. Unlike most transcription factors, EBNA2 does not bi nd directly to its cis-responsive DNA element but requires a cellular factor, termed C-promoter binding factor 1 (CBF1). Here, CBF1 was puri fied and was found to directly interact with EBNA2. CBF1 is identical to a protein thought to be involved in immunoglobulin gene rearrangeme nt, RBPJ(k)appa. Contrary to previous reports, CBF1-RBPJ(k)appa did no t bind to the recombination signal sequences but instead bound to site s in the EBV C-promoter and in the CD23 promoter.