Transcriptional activator that binds to E2f sites. Required for wild-type growth in mitotic and polytene tissues, Contributes to the expression of replication genes at the G1-S transition and Cyclin E. Activates cell proliferation in wing imaginal disk, which requires expression of vg. Heterodimer of E2f and Dp. Cooperates to give sequence-specific DNA binding and optimal trans-activation. Interacts with PCNA. Segmentally repeated expression throughout early embryos is restricted to the ventral nerve cord in later embryos. Throughout embryonic development. The PIP-box K+4 motif mediates both the interaction with PCNA and the recruitment of the DCX(DTL) complex: while the PIP-box interacts with PCNA, the presence of the K+4 submotif, recruits the DCX(DTL) complex, leading to its ubiquitination. Ubiquitinated by the DCX(DTL) complex, also named CRL4(CDT2) complex, leading to its degradation during S phase. Ubiquitination by the DCX(DTL) complex is essential for cell cycle control and is PCNA-dependent: interacts with PCNA via its PIP-box, while the presence of the containing the 'K+4' motif in the PIP box, recruit the DCX(DTL) complex, leading to its degradation. Belongs to the E2F/DP family.