Abstract
In Arabidopsis, FT is one of the genes which are located most downstream in regulatory cascade of flowering. FT encodes a protein of the PEBP/RKIP family and functions interdependently with another flowering-time gene FD. FD encodes a bZIP transcription factor and is expressed in shoot apex. FT and FD proteins interact in vitro and in yeast cells. FT is expressed in vascular tissues of cotyledons and leaves. However, when expressed in shoot apex, FT can complement ft loss-of-function mutant phenotype. These facts suggest that FT acts with FD in shoot apex. Fluorescence from functional FT:EGFP fusion protein was observed in both nucleus and cytoplasm, and EYFP:FD fluorescence was observed only in nucleus.
We analyzed protein interaction in planta by BiFC and observed 35S::FT:GR plant phenotype. These results suggest that FT functions in the nucleus with FD to regulate expression of downstream genes.
