E2F1 AND E1A(12S) HAVE A HOMOLOGOUS ACTIVATION DOMAIN REGULATED BY RBAND CBP

The E2F1 transcription factor has a well-characterized activation doma in at its C terminus and the E1A protein has a recently defined activa tion domain at its N terminus. Here we show that these activation doma ins are highly related in sequence. The sequence homology reflects, at least partly, the conservation of common binding sites for the RE and CBP/p300 proteins, which are preserved in the same relative order alo ng F2F1 and E1A, Furthermore, the interaction of RE and CBP with these two activation domains results in the same functional consequences: R E represses both activation domains, whereas CBP stimulates them. We c onclude that the activation domains of E1A(12S) and E2F1 belong to a n ovel functional class, characterized by specific protein binding sites . The implication of this conservation with respect to E1A-induced sti mulation of E2F activity is discussed.