MASKING OF THE CBF1 RBPJ(KAPPA) TRANSCRIPTIONAL REPRESSION DOMAIN BY EPSTEIN-BARR-VIRUS EBNA2/

Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA2) is a transcriptiona l activator that is essential for EBV-driven B cell immortalization. E BNA2 is targeted to responsive promoters through interaction with a ce llular DNA binding protein, C promoter binding factor 1 (CBF1). A tran scriptional repression domain has been identified within CBF1. This do main also interacts with EBNA2, and repression is masked by EBNA2 bind ing. Thus, EBNA2 acts by countering transcriptional repression. Mutati on at amino acid 233 of CBF1 abolishes repression and correlates with a loss-of-function mutation in the Drosophila homolog Su(H).