The molecular basis of temperature compensation in the Arabidopsis circadian clock
The molecular basis of temperature compensation in the Arabidopsis circadian clock
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DOI：
10.1105/tpc.105.039990
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发表时间：
2006-05-01
期刊：
影响因子：
11.6
通讯作者：
Hall, A
中科院分区：
文献类型：
--
作者：
Gould, PD;Locke, JCW;Hall, A
生理时钟在广泛的生理温度范围内保持稳健和准确的计时，这一特性被称为温度补偿。在拟南芥中，环境温度影响编码CAB表达1 （TOC1）、GIGANTEA （GI）以及部分冗余基因CIRCADIAN clock ASSOCIATED1 （CCA1）和LATE ELONGATED HYPOCOTYL （LHY）的时钟成分的转录本的节律性积累。随着温度的升高（从17℃到27℃），TOC1和GI RNA节律的振幅和峰值水平增加，而LHY则降低。然而，随着温度的降低（从17℃到12℃），CCA1和LHY RNA节律的振幅和峰值表达水平增加。在27℃时，GI和LHY之间的动态平衡允许野生型植物的温度补偿，但Ihy和GI突变植物的昼夜节律功能受损。然而，在12℃下，CCA1比LHY对缓冲机制的影响更大，因为CCA1和gi突变在较低温度下比Ihy更严重地损害了昼夜节律。在17℃时，虽然部分胃肠功能会影响昼夜节律，但胃肠功能对于自由运行的昼夜节律显然是不可或缺的。使用互锁环模型的数值模拟表明，平衡LHY/CCA1功能对抗GI和其他夜间表达基因可以在很大程度上解释野生型植物的温度补偿和GI突变体的温度特异性表型。
Circadian clocks maintain robust and accurate timing over a broad range of physiological temperatures, a characteristic termed temperature compensation. In Arabidopsis thaliana, ambient temperature affects the rhythmic accumulation of transcripts encoding the clock components TIMING OF CAB EXPRESSION1 (TOC1), GIGANTEA (GI), and the partially redundant genes CIRCADIAN CLOCK ASSOCIATED1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY). The amplitude and peak levels increase for TOC1 and GI RNA rhythms as the temperature increases (from 17 to 27 degrees C), whereas they decrease for LHY. However, as temperatures decrease ( from 17 to 12 degrees C), CCA1 and LHY RNA rhythms increase in amplitude and peak expression level. At 27 degrees C, a dynamic balance between GI and LHY allows temperature compensation in wild-type plants, but circadian function is impaired in Ihy and gi mutant plants. However, at 12 degrees C, CCA1 has more effect on the buffering mechanism than LHY, as the cca1 and gi mutations impair circadian rhythms more than Ihy at the lower temperature. At 17 degrees C, GI is apparently dispensable for free-running circadian rhythms, although partial GI function can affect circadian period. Numerical simulations using the interlocking-loop model show that balancing LHY/CCA1 function against GI and other evening-expressed genes can largely account for temperature compensation in wild-type plants and the temperature-specific phenotypes of gi mutants.