Abstract
Late-flowering mutant fwa is a dominant epigenetic mutant that ectopically expresses a GL2-type HD-ZIP gene due to promoter hypomethylation (Soppe et al. 2000). In wild type, however, FWA is not expressed during vegetative phase, and loss-of-function mutants of FWA are indistinguishable from wild type in flowering time. These facts suggest that FWA per se is not a component of the regulatory mechanisms of flowering. Recent findings that over-expression of other GL2-type HD-ZIP genes, ANL2 and PDF2, also resulted in late-flowering phenotype (Weigel et al. 2000; Abe et al. in press) prompted us to hypothesize that ectopically-expressed GL2-type HD-ZIP proteins somehow interfere 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 unique tools to dissect pathway from FT to flowering. We are currently investigating FWA-interacting proteins using yeast two-hybrid system. Results will be presented.
