Abstract
Phytochrome is one of the major photoreceptor families in plants and regulates flowering mechanism. The VOZ (Vascular plant One-Zinc finger) protein, first identified as a transcription factor that binds to the cis-acting region of the Arabidopsis V-PPase gene, was isolated as a phytochrome-interacting factor by yeast-two hybrid screening, using a cDNA library derived from bolting Arabidopsis plant. The phytochrome-VOZ interaction was confirmed by in vitro pull-down assay. VOZ is conserved among various land plants, and Arabidopsis possesses two genes, AtVOZ1 and AtVOZ2. voz1/voz2 double mutant showed late-flowering phenotype under long-day condition, suggesting that VOZ functions in flowering regulation dependent on photoperiod. Analysis on phyB/voz1/voz2 triple mutant indicates that VOZ functions downstream of phyB. Compared with WT, the FT mRNA level was greatly reduced in the voz1/voz2 double mutant, whereas no difference was observed in the CO mRNA level.
