Probable transcription factor active in inflorescence development and floral organogenesis. Functions with SEPALLATA1/AGL2 and SEPALLATA2/AGL4 to ensure proper development of petals, stamens and carpels and to prevent the indeterminate growth of the flower meristem. Interacts with APETALA1, AGAMOUS or APETALA3/PISTILLATA to form complexes, that could be involved in genes regulation during floral meristem development (PubMed:10821278, PubMed:11206550). Binds specifically to the CArG box DNA sequence 5'-CC (A/T)6 GG-3' (PubMed:16080001). Forms homodimers (PubMed:25228343). Heterodimer with AP1 or AG capable of binding to CArG-box sequences. Binds AP3/PI to form a ternary complex. Interacts with AGL16 (PubMed:15805477). Interacts with TT16/AGL32 (PubMed:16080001). Expressed early during flower development within petals, stamens, and carpels. Triple mutations in the SEP1, SEP2 and SEP3 genes result in the replacement of the stamens and petals by sepals and of the carpels by a new mutant flower with sepaloid organs. May be due to a competing acceptor splice site. Truncated N-terminus.