PLoS ONE (Jan 2012)

Interactions and CCAAT-binding of Arabidopsis thaliana NF-Y subunits.

  • Valentina Calvenzani,
  • Barbara Testoni,
  • Giuliana Gusmaroli,
  • Mariangela Lorenzo,
  • Nerina Gnesutta,
  • Katia Petroni,
  • Roberto Mantovani,
  • Chiara Tonelli

DOI
https://doi.org/10.1371/journal.pone.0042902
Journal volume & issue
Vol. 7, no. 8
p. e42902

Abstract

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BackgroundNF-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.MethodsWe 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.ResultsConsistent 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.ConclusionsOur 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.