Nuclear Factor Y (NF-Y) is a heterotrimeric transcription factor that binds CCAAT elements. The NF-Y trimer is composed of a Histone Fold Domain (HFD) dimer (NF-YB/NF-YC) and NF-YA, which confers DNA sequence specificity. NF-YA shares a conserved domain with the CONSTANS, CONSTANS-LIKE, TOC1 (CCT) proteins. We show that CONSTANS (CO/B-BOX PROTEIN1 BBX1), a master flowering regulator, forms a trimer with Arabidopsis thaliana NF-YB2/NF-YC3 to efficiently bind the CORE element of the FLOWERING LOCUS T promoter. We term this complex NF-CO. Using saturation mutagenesis, electrophoretic mobility shift assays, and RNA-sequencing profiling of co, nf-yb, and nf-yc mutants, we identify CCACA elements as the core NF-CO binding site. CO physically interacts with the same HFD surface required for NF-YA association, as determined by mutations in NF-YB2 and NF-YC9, and tested in vitro and in vivo. The co-7 mutation in the CCT domain, corresponding to an NF-YA arginine directly involved in CCAAT recognition, abolishes NF-CO binding to DNA. In summary, a unifying molecular mechanism of CO function relates it to the NF-YA paradigm, as part of a trimeric complex imparting sequence specificity to HFD/DNA interactions. It is likely that members of the large CCT family participate in similar complexes with At-NF-YB and At-NF-YC, broadening HFD combinatorial possibilities in terms of trimerization, DNA binding specificities, and transcriptional regulation.
CONSTANS imparts DNA sequence specificity to the histone fold NF-YB/NF-YC dimer / N. Gnesutta, R.W. Kumimoto, S. Swain, M. Chiara, C. Siriwardana, D.S. Horner, B.F. Holt, R. Mantovani. - In: PLANT CELL. - ISSN 1040-4651. - 29:6(2017 Jun), pp. 1516-1532.
|Titolo:||CONSTANS imparts DNA sequence specificity to the histone fold NF-YB/NF-YC dimer|
GNESUTTA, NERINA BRUNA (Primo)
MANTOVANI, ROBERTO (Corresponding)
|Settore Scientifico Disciplinare:||Settore BIO/10 - Biochimica|
Settore BIO/11 - Biologia Molecolare
Settore BIO/18 - Genetica
|Data di pubblicazione:||giu-2017|
|Data ahead of print / Data di stampa:||19-mag-2017|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1105/tpc.16.00864|
|Appare nelle tipologie:||01 - Articolo su periodico|