Inhibitor of E2F-dependent activation of gene expression. Binds specifically the E2 recognition site without interacting with DP proteins and prevents transcription activation by E2F/DP heterodimers. Does not bind retinoblastoma-related proteins. Acts as a growth regulator but is not associated with changes in the expression of cell cycle marker genes or in nuclear ploidy levels. Has no effect on cell proliferation, but may repress cell wall biosynthesis genes during cell elongation in differentiated cells. High expression in young cotyledons and leaves, hypocotyls, shoot apical meristem, roots and mature pollen grains, moderate in developing trichomes, flowers and at early stages of developing anthers, and barely detectable in mature leaves. Not detected in primary root meristem, emerging lateral roots, pistils, developing embryos and siliques. Expressed in a cell cycle-dependent manner. Most abundant in mid-S phase. Belongs to the E2F/DP family.