Abstract
Late-flowering mutant fwa is a dominant epigenetic mutant that ectopically expresses a GL2-type HD-ZIP gene due to promoter hypomethylation. In wild type, FWA is not expressed during vegetative phase. This suggests that ectopically-expressed FWA somehow interferes the regulatory mechanisms of flowering. Genetic analysis suggests that FWA blocks the pathway at FT and/or downstream of FT. We envisage that FWA may provide a unique tool to dissect pathway from FT to flowering. We examined protein-interaction of FWA with FT and a bZIP protein FD. Our results showed that FWA can strongly bind to FT, but not to FD. This suggests that ectopically-expressed FWA inhibits floral transition by interfering with the interaction between FT and FD through binding to FT. Since interference of FT function alone cannot fully explain fwa phenotype, we are investigating other proteins that interact with FWA using yeast two-hybrid screening. Results of these analyses will be presented.
