Atypical E2F transcription factor that participates in various processes such as angiogenesis and polyploidization of specialized cells. Mainly acts as a transcription repressor that binds DNA independently of DP proteins and specifically recognizes the E2 recognition site 5'-TTTC[CG]CGC-3'. Directly represses transcription of classical E2F transcription factors such as e2f1. Acts as a regulator of S-phase by recognizing and binding the E2-related site 5'-TTCCCGCC-3' and mediating repression of G1/S-regulated genes. Acts as a promoter of sprouting angiogenesis, possibly by acting as a transcription activator (By similarity). Homodimer and heterodimer: mainly forms homodimers and, to a lesser extent, heterodimers with e2f7. In contrast to classical members of the E2F transcription factor, atypical members contain 2 DNA-binding domains and regulate transcription in a DP-independent manner. Both DNA-binding domains are required for DNA-binding and are proposed to form an intramolecular structure that is similar to the winged helix structure of the E2F-DP heterodimer (By similarity). Belongs to the E2F/DP family.