Kircher S, Kozma-Bognar L, Kim L, Adam E, Harter K, Schafer E, Nagy F
Institut fur Biologie II/Botanik, Universitat Freiburg, Schanzlestrasse 1, D-79104 Freiburg, Germany.
Plant Cell. 1999 Aug;11(8):1445-56. doi: 10.1105/tpc.11.8.1445.
The phytochrome (phy) family of plant photoreceptors controls various aspects of photomorphogenesis. Overexpression of rice phyA-green fluorescent protein (GFP) and tobacco phyB-GFP fusion proteins in tobacco results in functional photoreceptors. phyA-GFP and phyB-GFP are localized in the cytosol of dark-adapted plants. In our experiments, red light treatment led to nuclear translocation of phyA-GFP and phyB-GFP, albeit with different kinetics. Red light-induced nuclear import of phyB-GFP, but not that of phyA-GFP, was inhibited by far-red light. Far-red light alone only induced nuclear translocation of phyA-GFP. These observations indicate that nuclear import of phyA-GFP is controlled by a very low fluence response, whereas translocation of phyB-GFP is regulated by a low fluence response of phytochrome. Thus, light-regulated nucleocytoplasmic partitioning of phyA and phyB is a major step in phytochrome signaling.
植物光受体的光敏色素（phy）家族控制着光形态建成的各个方面。在烟草中过表达水稻phyA-绿色荧光蛋白（GFP）和烟草phyB-GFP融合蛋白可产生功能性光受体。phyA-GFP和phyB-GFP定位于暗适应植物的细胞质中。在我们的实验中，红光处理导致phyA-GFP和phyB-GFP发生核转位，尽管动力学不同。远红光抑制了红光诱导的phyB-GFP核输入，但不抑制phyA-GFP的核输入。单独的远红光仅诱导phyA-GFP的核转位。这些观察结果表明，phyA-GFP的核输入受极低光通量反应的控制，而phyB-GFP的转位受光敏色素的低光通量反应调节。因此，光调节的phyA和phyB在核质间的分配是光敏色素信号传导的一个主要步骤。
