The EC night-time repressor plays a crucial role in modulating circadian clock transcriptional circuitry by conservatively double-checking both warm-night and night-time-light signals in a synergistic manner in Arabidopsis thaliana.
The EC night-time repressor plays a crucial role in modulating circadian clock transcriptional circuitry by conservatively double-checking both warm-night and night-time-light signals in a synergistic manner in Arabidopsis thaliana.
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DOI：
10.1093/pcp/pcu144
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发表时间：
2014-12
影响因子：
4.9
通讯作者：
T. Mizuno;Miki Kitayama;Haruka Oka;Mayuka Tsubouchi;Chieko Takayama;Yuji Nomoto;T. Yamashino
中科院分区：
文献类型：
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作者：
T. Mizuno;Miki Kitayama;Haruka Oka;Mayuka Tsubouchi;Chieko Takayama;Yuji Nomoto;T. Yamashino
在过去的十年中，拟南芥在确定植物生物钟背后的分子机制方面取得了重大研究进展。生物钟必须能够将外部光和环境温度信号集成到其转录电路中，以正确调节其功能。我们之前表明，包括 LUX (LUX ARRHYTHMO)、GI (GIGANTEA)、LNK1（夜光诱导和时钟调节基因 1）、PRR9（伪响应调节器 9）和 PRR7 在内的一组时钟基因的转录通常通过夜间复合物 (EC) 夜间抑制子进行调节，以响应温度的适度变化 (Δ6°C) 和温度的差异。稳态 适合生长的温度（16-28°C）。在这里，我们进一步表明，夜间光信号也通过 EC 夜间抑制子馈入生物钟转录电路，因此同一组 EC 靶基因响应夜间光脉冲而上调。这种光诱导的事件依赖于光敏色素，但不依赖于隐花色素。有趣的是，暖夜和夜间光信号都以协同方式负向调节 EC 夜间抑制子的活性。换句话说，只有当这些信号同时输入阻遏蛋白时，才能观察到 EC 靶基因转录的指数爆发。综上所述，我们认为 EC 夜间抑制子在调节时钟转录电路中发挥着至关重要的作用，通过保守地双重检查外部光和环境温度信号来正确跟踪光和热循环的季节变化。
During the last decade, significant research progress has been made in Arabidopsis thaliana in defining the molecular mechanisms behind the plant circadian clock. The circadian clock must have the ability to integrate both external light and ambient temperature signals into its transcriptional circuitry to regulate its function properly. We previously showed that transcription of a set of clock genes including LUX (LUX ARRHYTHMO), GI (GIGANTEA), LNK1 (NIGHT LIGHT-INDUCIBLE AND CLOCK-REGULATED GENE 1), PRR9 (PSEUDO-RESPONSE REGULATOR 9) and PRR7 is commonly regulated through the evening complex (EC) night-time repressor in response to both moderate changes in temperature (Δ6°C) and differences in steady-state growth-compatible temperature (16-28°C). Here, we further show that a night-time-light signal also feeds into the circadian clock transcriptional circuitry through the EC night-time repressor, so that the same set of EC target genes is up-regulated in response to a night-time-light pulse. This light-induced event is dependent on phytochromes, but not cryptochromes. Interestingly, both the warm-night and night-time-light signals negatively modulate the activity of the EC night-time repressor in a synergistic manner. In other words, an exponential burst of transcription of the EC target genes is observed only when these signals are simultaneously fed into the repressor. Taken together, we propose that the EC night-time repressor plays a crucial role in modulating the clock transcriptional circuitry to keep track properly of seasonal changes in photo- and thermal cycles by conservatively double-checking the external light and ambient temperature signals.