Interactions and CCAAT-binding of Arabidopsis thaliana NF-Y subunits.
BACKGROUND
NF-Y is a transcription factor that recognizes with high specificity and affinity the widespread CCAAT box promoter element. It is formed by three subunits: NF-YA and the NF-YB/NF-YC- heterodimer containing histone fold domains (HFDs). We previously identified a large NF-Y gene family in Arabidopsis thaliana, composed of 29 members, and characterized their expression patterns in various plant tissues.


METHODS
We used yeast Two-hybrids assays (Y2H), pull-down and Electrophoretic Mobility Shift Assay (EMSA) in vitro experiments with recombinant proteins to dissect AtNF-YB/AtNF-YC interactions and DNA-binding with different AtNF-YAs.


RESULTS
Consistent with robust conservation within HFDs, we show that heterodimerization is possible among all histone-like subunits, including the divergent and related LEC1/AtNF-YB9 and L1L/AtNF-YB6 required for embryo development. DNA-binding to a consensus CCAAT box was investigated with specific AtNF-YB/AtNF-YC combinations and observed with some, but not all AtNF-YA subunits.


CONCLUSIONS
Our results highlight (i) the conserved heterodimerization capacity of AtNF-Y histone-like subunits, and (ii) the different affinities of AtNF-YAs for the CCAAT sequence. Because of the general expansion of NF-Y genes in plants, these results most likely apply to other species.
Dipartimento di Bioscienze, Università degli Studi di Milano, Milano, Italy.
Valentina
V
Calvenzani
Barbara
B
Testoni
Giuliana
G
Gusmaroli
Mariangela
M
Lorenzo
Nerina
N
Gnesutta
Katia
K
Petroni
Roberto
R
Mantovani
Chiara
C
Tonelli
D000818:Animals; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D023081:CCAAT-Binding Factor / Q000235:genetics* / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D019281:Dimerization; D024202:Electrophoretic Mobility Shift Assay; D006657:Histones / Q000378:metabolism; D051379:Mice; D005810:Multigene Family / Q000235:genetics*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D023081:CCAAT-Binding Factor; D017931:DNA Primers; D006657:Histones; D021122:Protein Subunits