Mapping the Core of the Arabidopsis Circadian Clock Defines the Network Structure of the Oscillator
Mapping the Core of the Arabidopsis Circadian Clock Defines the Network Structure of the Oscillator
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DOI：
10.1126/science.1219075
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发表时间：
2012-04-06
期刊：
影响因子：
56.9
通讯作者：
Mas, P.
中科院分区：
文献类型：
--
作者：
Huang, W.;Perez-Garcia, P.;Mas, P.
在许多生物体中，生物钟由功能上耦合的早晨和晚上振荡器组成。在拟南芥中，振荡器耦合依赖于一个核心环，其中晚上振荡器组件CAB表达的时间1（TOC1）被提议激活早晨表达的振荡器基因的一个子集。在这里，我们表明，TOC1不作为一个激活剂，而是作为一个一般的抑制振荡基因的表达。抑制通过TOC1与振荡基因的启动子的节律性关联而发生。TOC1的激素依赖性诱导和RNA干扰植物的分析表明，TOC1阻止在夜间激活早晨表达的基因。我们的研究推翻了拟南芥昼夜节律钟的流行模型，表明早晨和晚上的振荡器回路是通过TOC1的抑制活性连接的。
In many organisms, the circadian clock is composed of functionally coupled morning and evening oscillators. In Arabidopsis, oscillator coupling relies on a core loop in which the evening oscillator component TIMING OF CAB EXPRESSION 1 (TOC1) was proposed to activate a subset of morning-expressed oscillator genes. Here, we show that TOC1 does not function as an activator but rather as a general repressor of oscillator gene expression. Repression occurs through TOC1 rhythmic association to the promoters of the oscillator genes. Hormone-dependent induction of TOC1 and analysis of RNA interference plants show that TOC1 prevents the activation of morning-expressed genes at night. Our study overturns the prevailing model of the Arabidopsis circadian clock, showing that the morning and evening oscillator loops are connected through the repressing activity of TOC1.