The circadian clock controls the expression pattern of the circadian input photoreceptor, phytochrome B
The circadian clock controls the expression pattern of the circadian input photoreceptor, phytochrome B
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DOI：
10.1073/pnas.96.25.14652
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发表时间：
1999-12-07
影响因子：
11.1
通讯作者：
Millar, AJ
中科院分区：
文献类型：
--
作者：
Bognár, LK;Hall, A;Millar, AJ
在高等植物的整个生命周期中，发育和生理反应都受到光的调节。为了感知光环境的变化，植物已经发展出各种光感受器，包括吸收红光/远红光的光敏色素和吸收蓝光的隐花色素。包括大多数光反应在内的各种生理反应也受到由内源性振荡器（昼夜节律钟）产生的昼夜节律的调节。为了提供关于当地时间的信息，生物钟被环境雾凇线索同步和引导，其中光是最重要的。光驱动的拟南芥生物钟的夹带已被证明是由光敏色素A（phyA），光敏色素B（phyB），和隐花色素1和2介导的，从而肯定了这些光感受器作为输入调节植物生物钟的作用。在这里，我们表明，PHYB：：LUC报告基因的表达包含烟草NtPHYB 1或拟南芥AtPHYB基因的启动子和5'非翻译区融合到荧光素酶（LUC）基因表现出强大的昼夜节律振荡转基因植物。我们证明，丰富的PHYB RNA保留这种昼夜调节，并使用PHYB：：Luc融合蛋白，以显示PHYB的合成速率也是有节奏的。然而，大量PHYB蛋白的丰度仅表现出较弱的昼夜节律性（如果有的话）。这些数据表明，光感受器基因的表达模式可能是显着的植物生理的日常调节，并表明在高等植物中的输入途径和假定的昼夜节律钟机制的组件之间的一个意想不到的亲密关系。
Developmental and physiological responses are regulated by light throughout the entire life cycle of higher plants. To sense changes in the light environment plants have developed various photoreceptors, including the red/far-red light-absorbing phytochromes and blue light-absorbing cryptochromes. A wide variety of physiological responses, including most light responses, also are modulated by circadian rhythms that are generated by an endogenous oscillator, the circadian clock. To provide information on local time, circadian clocks are synchronized and entrained by environmental rime cues, of which light is among the most important. Light-driven entrainment of the Arabidopsis circadian clock has been shown to be mediated by phytochrome A (phyA), phytochrome B (phyB), and cryptochromes 1 and 2, thus affirming the roles of these photoreceptors as input regulators to the plant circadian clock. Here we show that the expression of PHYB::LUC reporter genes containing the promoter and 5' untranslated region of the tobacco NtPHYB1 or Arabidopsis AtPHYB genes fused to the luciferase (LUC) gene exhibit robust circadian oscillations in transgenic plants. We demonstrate that the abundance of PHYB RNA retains this circadian regulation and use a PHYB::Luc fusion protein to show that the rate of PHYB synthesis is also rhythmic. The abundance of bulk PHYB protein, however, exhibits only weak circadian rhythmicity, if any. These data suggest that photoreceptor gene expression patterns may be significant in the daily regulation of plant physiology and indicate an unexpectedly intimate relationship between the components of the input pathway and the putative circadian clock mechanism in higher plants.