Gil P, Kircher S, Adam E, Bury E, Kozma-Bognar L, Schäfer E, Nagy F
Institut für Biologie II, Universität Freiburg, Schänzlestr. 1, D-79104 Freiburg, Hungary.
Plant J. 2000 Apr;22(2):135-45. doi: 10.1046/j.1365-313x.2000.00730.x.
Photomorphogenesis of higher plants is regulated by photoreceptors including the red/far-red light-absorbing phytochromes, blue-UV/A sensing cryptochromes and as yet uncharacterized UV/B receptors. Specific phototransduction pathways that are controlled by either individual or interacting photoreceptors mediate regulation. Phytochrome B (phyB) is the major red light-sensing photoreceptor. Phototransduction mediated by this light sensor has been shown to include light-dependent nuclear import and interaction of phyB with transcription factor-like proteins in the nucleus. Here we report that nuclear import of phyB and physiological responses regulated by this photoreceptor exhibit very similar wavelength- and fluence rate-dependence. Nuclear import of phyB is insensitive to single red, blue and far-red light pulses. It is induced by continuous red light and to a lesser extent by continuous blue light, whereas far-red light is completely ineffective. The data presented indicate that light-dependent partitioning of phyB exhibits features characteristic of blue light responsiveness amplification, a phenomenon that is thought to be mediated by interaction of phyB with CRY1.
高等植物的光形态建成受光受体调控，这些光受体包括吸收红光/远红光的光敏色素、感应蓝光/紫外光A的隐花色素以及尚未明确的紫外光B受体。由单个或相互作用的光受体控制的特定光信号转导途径介导了这种调控。光敏色素B（phyB）是主要的红光感应光受体。由这种光传感器介导的光信号转导已被证明包括依赖光的核输入以及phyB与细胞核中类转录因子蛋白的相互作用。在此，我们报告phyB的核输入以及由该光受体调控的生理反应表现出非常相似的波长和光通量率依赖性。phyB的核输入对单个红光、蓝光和远红光脉冲不敏感。它由连续红光诱导，在较小程度上由连续蓝光诱导，而远红光则完全无效。所呈现的数据表明，phyB的光依赖分配表现出蓝光反应放大的特征，这种现象被认为是由phyB与CRY1的相互作用介导的。
