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 DRTF1/E2F complex functions in the control of cell-cycle progression from G1 to S phase. E2F3 binds specifically to RB1 in a cell-cycle dependent manner. Inhibits adipogenesis, probably through the repression of CEBPA binding to its target gene promoters (By similarity). Component of the DRTF1/E2F transcription factor complex. Binds cooperatively with TFDP1/Dp-1 to E2F sites. Interacts with retinoblastoma protein RB1 and related proteins (such as RBL1) that inhibit the E2F transactivation domain. Binds EAPP. Belongs to the E2F/DP family.