Abstract
Accumulating evidence supports a role for members of the plant Nuclear Factor Y (NF-Y) family of CCAAT-box binding transcription factors in the regulation of flowering time. In this study we have used a genetic approach to show that the homologous proteins NF-YB3 and NF-YB2 have comparable activities and play additive roles in the promotion of flowering, specifically under inductive photoperiodic conditions. We demonstrate that NF-YB2 and NF-YB3 are both essential for the normal induction of flowering by long-days and act through regulation of the expression of FLOWERING LOCUS T (FT). Using an ELISA-based in-vitro assay, we provide a novel demonstration that plant NF-YB subunits are capable of directly binding to a CCAAT-box containing region of the FLOWERING LOCUS T promoter as part of an NF-Y trimer in combination with the yeast HAP2 and HAP5 subunits. These results support an emerging model in which NF-Y complexes provide a component of the DNA target specificity for transcriptional regulators such as CONSTANS.
MeSH terms
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Amino Acid Sequence
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Arabidopsis / genetics
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Arabidopsis / metabolism
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Arabidopsis / physiology*
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism
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Arabidopsis Proteins / physiology*
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CCAAT-Binding Factor / genetics
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CCAAT-Binding Factor / metabolism
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CCAAT-Binding Factor / physiology*
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DNA, Bacterial
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Enzyme-Linked Immunosorbent Assay
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Flowers / genetics
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Flowers / metabolism
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Flowers / physiology*
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Gene Expression Regulation, Plant
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Genotype
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Molecular Sequence Data
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Mutagenesis, Insertional
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Photoperiod*
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Plants, Genetically Modified / genetics
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Plants, Genetically Modified / metabolism
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Plants, Genetically Modified / physiology
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Protein Binding
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Reverse Transcriptase Polymerase Chain Reaction
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Sequence Homology, Amino Acid
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Transcription Factors / genetics
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Transcription Factors / metabolism
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Transcription Factors / physiology
Substances
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Arabidopsis Proteins
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CCAAT-Binding Factor
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DNA, Bacterial
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FT protein, Arabidopsis
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NF-YB1 protein, Arabidopsis
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NF-YB2 protein, Arabidopsis
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T-DNA
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Transcription Factors
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nuclear factor Y