Abstract
Plants utilize specific photoreceptors such as phytochrome to survive. Phytochrome consists of three sub-families, phyA-C. Among them, phyA has specific functions. For instance, strong physiological responses by phyA is observed not under continuous red but under far-red light. We have been studying the structural basis for the phyA-specific properties using phyA/phyB chimera. Recently, we have shown that the phyA sequence in the N-PAS domain sufficiently confers the nuclear accumulation activity under continuous FR (Ono et al., JSPS Annual Meeting, 2009). In contrast, PHY domain is additionally important for the signaling. In the present study, we first narrowed down the phyA sequence required for the nuclear localization For this purpose, the phyA N-PAS sequence was further divided into three parts and respective chimeric sequences were prepared. Preliminary analysis suggested that the phyA sequence in the N-terminal extension sufficiently conferred the nuclear localization activity. In addition, a chimeric phyB molecule, in which the PHY domain was replaced with that of phyA, was fused to a NLS and expressed in Arabidopsis. Detailed analysis of those lines is in progress.
