Figure 7.

Combinatorial Circuitry Controlling Production of and Response to Florigenic Proteins in Rice.

In leaves, Hd3a and RFT1 can promote expression of Ehd1 by forming a canonical FAC with OsFD1 and Gf14c, and they can repress it by interacting with HBFs. Hd3a can interact directly with HBFs, whereas RFT1 might interact indirectly with HBFs through GF14c. Binding of HBF1 to the Ehd1 promoter is direct. Upon translocation to the meristem, Hd3a and RFT1 proteins can promote transcription of OsMADS target genes by forming a canonical FAC. HBF1 at least can repress transcription of the same targets by forming a repressive FAC. Gray arrows and flat-end arrows indicate transcriptional activation and repression, respectively. Connectors indicate protein-protein interactions. Thick, black flat-end arrows indicate direct repression by protein-DNA binding. Dashed arrows indicate protein movement.