Abstract
In higher plants, Z,E-mixed polyisoprenoids, including dolichol and polyprenol, are biosynthesized, showing two different distribution patterns in the chain length, C50-60 and C70-120. However, physiological role of Z,E-mixed polyisoprenoids in higher plants is hardly elucidated. To understand the physiological functions of Z,E-mixed polyisoprenoids, we have cloned and characterized 6 cDNAs encoding cis-prenyltransferase (CPT), which catalyzes formation of the structural backbone of Z,E-mixed polyisoprenoids, in Arabidopsis thaliana.
Crude proteins prepared from yeast strains harboring each AtCPT except AtrCPT4 showed CPT activity in vitro, catalyzing the formation of C80-100 polyprenyl products. In contrast, AtCPT4 showed CPT activity, catalyzing the formation of C50-60 polyprenyl products. Transposon Ds-inserted mutant of AtCPT4 showed increased elongation of petioles and hypocotyls under long-day condition, while no significant difference between mutant and wild-type grown in the dark. Moreover, expression of AtCPT4 was repressed in the seedling grown in the dark, but rapidly induced by irradiation of white light.
