Transcription activator that binds DNA cooperatively with DP proteins through the E2 recognition site, 5'-TTTC[CG]CGC-3' found in the promoter region of a number of genes whose products are involved in cell cycle regulation or in DNA replication. The binding of retinoblastoma-related proteins represses transactivation. Regulates gene expression both positively and negatively. Activates the expression of E2FB. Involved in the control of cell-cycle progression from G1 to S phase. Stimulates cell proliferation and delays differentiation. Heterodimer with DP proteins. Interacts (via dimerization domain) preferentially with DPA, but also with DPB. Interacts with maize retinoblastoma-related protein RBR1. No interaction with E2FD. Interaction with DPA induces an exclusive nuclear localization, but an interaction with DPB has no effect. Highly expressed in the shoot apical meristem, emerging leaf primordia, and vascular tissues of young leaf primordia. Expressed in flowers, in epidermis and cortex of hypocotyls, and at lower levels in leaves. Expressed in a cell cycle-dependent manner. Most abundant in early S phase. Decreased expression during the passage into G2. The C-terminal region (366-485) is required for transactivational activity. The N-terminal region (92-128) is important for nuclear localization. Belongs to the E2F/DP family.