Fig. 7. Model for the antagonistic regulation of SOC1 expression by CO and FLC. The horizontal line represents a 234 bp region of the SOC1 promoter with the indicated nucleotide endpoints. Arrows indicate promotion and T-bars indicate repression of SOC1 expression. We propose that FLC binds directly to a CArG box motif at nt –400 of the SOC1 promoter and may recruit a global repression complex (R) to DNA to repress transcription. CO is proposed to be recruited by a sequence-specific DNA-binding factor (X) to an adjacent motif located between nt –372 and –248 in the SOC1 promoter to mediate activation. Deletion of the CArG box does not abolish FLC-mediated repression, suggesting that FLC also represses SOC1 expression by other more indirect mechanisms.