Transcription factor that binds specifically to a 5'-AA[AG]G-3' consensus core sequence. A flanking TGT sequence contributes to the specificity of binding. Regulates a photoperiodic flowering response. Transcriptional repressor of 'CONSTANS' expression. The DNA-binding ability is not modulated by 'GIGANTEA' but the stability of CDF1 is controlled by the proteasome-dependent pathway. Ubiquitinated by the SCF(ADO3) E3 ubiquitin ligase complex. Binds to the FT promoter in the morning. Interacts with ADO2 (via kelch repeats), ADO3 (via kelch repeats) and GI (via N-terminus). Expressed in the vascular tissues of cotyledons, leaves and hypocotyls and in stomata. Not detected in roots. Circadian-regulation at the protein level, but not at the mRNA level. Strongly decreased expression during the dark phase. Accumulates at high levels at the beginning of the day. Ubiquitinated.