The Arabidopsis Mediator Subunit MED25 Differentially Regulates Jasmonate and Abscisic Acid Signaling through Interacting with the MYC2 and ABI5 Transcription Factors
The Arabidopsis Mediator Subunit MED25 Differentially Regulates Jasmonate and Abscisic Acid Signaling through Interacting with the MYC2 and ABI5 Transcription Factors
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拟南芥介导亚基 MED25 通过与 MYC2 和 ABI5 转录因子相互作用差异调节茉莉酸和脱落酸信号传导
DOI：
10.1105/tpc.112.098277
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发表时间：
2012-07-01
期刊：
影响因子：
11.6
通讯作者：
Li, Chuanyou
中科院分区：
文献类型：
--
作者：
Chen, Rong;Jiang, Hongling;Li, Chuanyou
转录调控在植物激素信号传导中起着核心作用。转录调控的核心是中介体，这是一种进化上保守的多亚基复合物，它是基因特异性转录因子和RNA聚合酶机制之间的桥梁，以调节转录。在这里，我们报道了拟南芥介质的MEDIATOR25 （MED25）亚基在调节茉莉酸和脱落酸（ABA）触发的基因转录中的作用机制。我们发现，在茉莉酸信号传导过程中，MED25在MYC2靶基因的启动子区域与基本螺旋-环螺旋转录因子MYC2物理结合，并对MYC2调控的基因转录产生积极影响。我们还发现MED25在ABI5靶基因的启动子区域与碱性亮氨酸拉链转录因子ABA-INSENSITIVE5 （ABI5）物理结合，并对ABI5调控的基因转录显示负作用。我们的研究结果表明，在MED25对茉莉酸和ABA信号传导的不同作用的基础上，MED25与MYC2和ABI5的相互作用机制是不同的。这些结果表明，拟南芥介质的MED25亚基通过选择性地与特定转录因子相互作用来调节广泛的信号通路。
Transcriptional regulation plays a central role in plant hormone signaling. At the core of transcriptional regulation is the Mediator, an evolutionarily conserved, multisubunit complex that serves as a bridge between gene-specific transcription factors and the RNA polymerase machinery to regulate transcription. Here, we report the action mechanisms of the MEDIATOR25 (MED25) subunit of the Arabidopsis thaliana Mediator in regulating jasmonate- and abscisic acid (ABA)-triggered gene transcription. We show that during jasmonate signaling, MED25 physically associates with the basic helix-loophelix transcription factor MYC2 in promoter regions of MYC2 target genes and exerts a positive effect on MYC2-regulated gene transcription. We also show that MED25 physically associates with the basic Leu zipper transcription factor ABA-INSENSITIVE5 (ABI5) in promoter regions of ABI5 target genes and shows a negative effect on ABI5-regulated gene transcription. Our results reveal that underlying the distinct effects of MED25 on jasmonate and ABA signaling, the interaction mechanisms of MED25 with MYC2 and ABI5 are different. These results highlight that the MED25 subunit of the Arabidopsis Mediator regulates a wide range of signaling pathways through selectively interacting with specific transcription factors.