Functional Analysis of Amino-Terminal Domains of the Photoreceptor Phytochrome B1[C][W]
Functional Analysis of Amino-Terminal Domains of the Photoreceptor Phytochrome B1[C][W]
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DOI：
10.1104/pp.110.153031
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发表时间：
2010-06
期刊：
影响因子：
7.4
通讯作者：
Andrea Palágyi;Kata Terecskei;É. Ádám;E. Kevei;S. Kircher;Zsuzsanna Mérai;Eberhard Schäfer;F. Nagy;László Kozma-Bognár
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文献类型：
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作者：
Andrea Palágyi;Kata Terecskei;É. Ádám;E. Kevei;S. Kircher;Zsuzsanna Mérai;Eberhard Schäfer;F. Nagy;László Kozma-Bognár
在拟南芥（Arabidopsis thaliana）的昼夜节律网络的核心，时钟基因/蛋白质形成多个转录/翻译负反馈环，并产生一个基本的约24小时的振荡，这提供了广泛的过程的日常调节。这种时间组织只有在与自然的昼夜循环相对应的情况下才能增强植物的适应性。光被光感受器吸收，是使振荡器与环境周期同步的最有效信号。光敏色素B（Phytochrome B，PHYB）是光生植物中主要的红光/远红光光敏色素受体。除了调节生物钟的节奏和相位外，PHYB还控制光形态建成和延迟开花。已经证明，核定位的PHYB的氨基末端结构域是能够控制光形态建成，部分，开花。在这里，我们表明（1）PHYB衍生物含有651或450个氨基酸残基的氨基末端结构域的功能，在介导红光信号的时钟，（2）昼夜节律的夹带是一个核功能的PHYB，和（3），410个氨基酸的氨基末端片段不具有任何功能的PHYB由于受损的发色团结合。然而，我们提供的证据表明，羧基末端结构域需要介导夹带在白色光，这表明该域的作用，在整合红色和蓝色光信号的时钟。此外，仔细分析phyB-9的昼夜节律表型表明，PHYB以不同的方式为昼夜节律振荡器的不同调节环提供光信号，这导致在特定光条件下，在没有PHYB的情况下，环的明显解耦。
At the core of the circadian network in Arabidopsis (Arabidopsis thaliana), clock genes/proteins form multiple transcriptional/translational negative feedback loops and generate a basic approximately 24-h oscillation, which provides daily regulation for a wide range of processes. This temporal organization enhances the fitness of plants only if it corresponds to the natural day/night cycles. Light, absorbed by photoreceptors, is the most effective signal in synchronizing the oscillator to environmental cycles. Phytochrome B (PHYB) is the major red/far-red light-absorbing phytochrome receptor in light-grown plants. Besides modulating the pace and phase of the circadian clock, PHYB controls photomorphogenesis and delays flowering. It has been demonstrated that the nuclear-localized amino-terminal domain of PHYB is capable of controlling photomorphogenesis and, partly, flowering. Here, we show (1) that PHYB derivatives containing 651 or 450 amino acid residues of the amino-terminal domains are functional in mediating red light signaling to the clock, (2) that circadian entrainment is a nuclear function of PHYB, and (3) that a 410-amino acid amino-terminal fragment does not possess any functions of PHYB due to impaired chromophore binding. However, we provide evidence that the carboxyl-terminal domain is required to mediate entrainment in white light, suggesting a role for this domain in integrating red and blue light signaling to the clock. Moreover, careful analysis of the circadian phenotype of phyB-9 indicates that PHYB provides light signaling for different regulatory loops of the circadian oscillator in a different manner, which results in an apparent decoupling of the loops in the absence of PHYB under specific light conditions.