FHY3 and FAR1 Act Downstream of Light Stable Phytochromes.
FHY3 and FAR1 Act Downstream of Light Stable Phytochromes.
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DOI：
10.3389/fpls.2016.00175
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发表时间：
2016
影响因子：
5.6
通讯作者：
Devlin PF
中科院分区：
文献类型：
--
作者：
Siddiqui H;Khan S;Rhodes BM;Devlin PF
FHY 3和FAR 1是拟南芥中直接调控许多靶基因表达的正性转录因子。在这里，我们研究了一个特定靶基因ELF 4的调控。我们证明了FHY 3和FAR 1在ELF 4上调中的作用是光依赖性的。此外，虽然FHY 3和FAR 1已被专门表征为光敏色素A信号通路的组成部分，因为它们在调节phyA核进口商的表达的重要性，我们表明，作为转录因子在自己的权利，FHY 3和FAR 1的光稳定光敏色素，phyB，phyD和phyE的下游行为。我们证明了光稳定光敏色素以红色/远红色可逆方式调节FHY 3蛋白的水平。我们还观察到ELF 4在晚上表现出特定的FHY 3和FAR 1介导的光诱导，并且我们表明此时光稳定光敏色素的调节很重要，因为它允许植物在黄昏之后维持正常的ELF 4表达，此时白天长度缩短，这是通过光不稳定光敏色素作用不可能实现的。在没有FHY 3和FAR 1的情况下，ELF 4表达福尔斯在黄昏时迅速下降，并且在短时间内，这导致ELF 4表达的早期下降，伴随着ELF 4靶基因在晚些时候的去抑制。因此，我们的研究结果表明FHY 3和FAR 1作为光稳定光敏色素信号传导的介质的重要作用。
FHY3 and FAR1 are positively acting transcription factors that directly regulate expression of a number of target genes in Arabidopsis thaliana. Here, we looked at the regulation of one specific target gene, ELF4. We demonstrate that the action of FHY3 and FAR1 in upregulation of ELF4 is light dependent. Furthermore, although FHY3 and FAR1 have been exclusively characterized as components of the phytochrome A signaling pathway because of their importance in regulating expression of phyA nuclear importers, we show that, as transcription factors in their own right, FHY3 and FAR1 act downstream of light stable phytochromes, phyB, phyD, and phyE. We demonstrate that light stable phytochrome acts in a red/far-red reversible manner to regulate the level of FHY3 protein. We also observed that ELF4 shows specific FHY3 and FAR1-mediated light induction in the evening and we show that regulation by light stable phytochromes at this time is important as it allows the plant to maintain normal ELF4 expression beyond dusk when the day length shortens, something which would not be possible through light labile phytochrome action. Without FHY3 and FAR1, ELF4 expression falls rapidly at dusk and in short days this results in an early drop in ELF4 expression, accompanied by a de-repression of an ELF4 target gene later in the night. Our results, therefore, demonstrate an important role for FHY3 and FAR1 as mediators of light stable phytochrome signaling.