Structural insights into the multivalent binding of the Arabidopsis FLOWERING LOCUS T promoter by the CO-NF-Y master transcription factor complex.
Lv, X., Zeng, X., Hu, H., Chen, L., Zhang, F., Liu, R., Liu, Y., Zhou, X., Wang, C., Wu, Z., Kim, C., He, Y., Du, J.(2021) Plant Cell 33: 1182-1195
- PubMed: 33693873 
- DOI: https://doi.org/10.1093/plcell/koab016
- Primary Citation of Related Structures:  
7CVO, 7CVQ - PubMed Abstract: 
Flowering plants sense various environmental and endogenous signals to trigger the floral transition and start the reproductive growth cycle. CONSTANS (CO) is a master transcription factor in the photoperiod floral pathway that integrates upstream signals and activates the florigen gene FLOWERING LOCUS T (FT). Here, we performed comprehensive structural and biochemical analyses to study the molecular mechanism underlying the regulation of FT by CO in Arabidopsis thaliana. We show that the four previously characterized cis-elements in the FT promoter proximal region, CORE1, CORE2, P1, and P2, are all direct CO binding sites. Structural analysis of CO in complex with NUCLEAR FACTOR-YB/YC (NF-YB/YC) and the CORE2 or CORE1 elements revealed the molecular basis for the specific recognition of the shared TGTG motifs. Biochemical analysis suggested that CO might form a homomultimeric assembly via its N-terminal B-Box domain and simultaneously occupy multiple cis-elements within the FT promoter. We suggest that this multivalent binding gives the CO-NF-Y complex high affinity and specificity for FT promoter binding. Overall, our data provide a detailed molecular model for the regulation of FT by the master transcription factor complex CO-NF-Y during the floral transition.
Organizational Affiliation: 
National Key Laboratory of Plant Molecular Genetics and Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 201602, China.