Abstract
Arabidopsis TERMINAL FLOWER 1 (TFL1) and FLOWERING LOCUS T (FT) are phosphatidylethanolamine-binding protein homologues with 59% amino residues identity, and both play important roles in flowering and inflorescence development, with antagonistic functions; while FT promotes flowering, TFL1 represses it. These proteins are believed to be regulators of bZIP transcription factors, FD and FD PALALOG (FDP). However, little is known about molecular mechanisms underlying the FD/FDP-dependent transcription controlled by TFL1. To investigate the mechanisms, we made transgenic plants over-expressing TFL1 proteins fused with transcriptional activator or repressor domains. Over-expressions of the activator fused TFL1 caused early flowering phenotype with terminal flowers, mimicking the tfl1 mutants. On the other hand, late flowering phenotype was conferred by the repressor fused TFL1 as well as by the non-fused TFL1. It is suggested from these data that TFL1 function was perturbed by the fusion of activator domain. We will discuss about the target gene expressions in these transgenic plants.
