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. E2F-4 binds with high affinity 
to RBL1 and RBL2. In some instances, can also bind RB protein.