Sugar and ABA responsiveness of a minimal RBCS light-responsive unit is mediated by direct binding of ABI4
Sugar and ABA responsiveness of a minimal RBCS light-responsive unit is mediated by direct binding of ABI4
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DOI：
10.1111/j.1365-313x.2005.02468.x
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发表时间：
2005-08-01
期刊：
影响因子：
7.2
通讯作者：
Herrera-Estrella, LR
中科院分区：
文献类型：
--
作者：
Acevedo-Hernández, GJ;León, P;Herrera-Estrella, LR
与光合作用相关的核基因（Phangs）能够对多种环境和发育信号做出反应，包括光，糖和脱落酸（ABA）。 Phang在转录调控的水平上进行了广泛的研究，并且在其启动子序列中已经确定了一些对于光反应性重要的元素。但是，尚未完全表征与糖和ABA调节有关的调节元素。使用保守的模块化排列5（CMA5），这是一个先前表征的最小光响应单元，我们表明，在拟南芥中，这个单元不仅对光信号有积极反应，而且对糖和ABA也负面反应。发现后一种反应在ABI4突变体中受到损害，表明脱节酸不敏感-4（ABI4）是涉及糖的调节剂，并且抑制了该最小调节单元。此外，我们报告了一个名为S-box的几个RBC启动子中保存的新序列元件，这对于CMA5的糖和ABA响应非常重要。该序列对应于一个假定的ABI4结合位点，实际上，该位点在体外受拟南芥ABI4蛋白的约束。 S-box与CMA5中存在的G-box密切相关，并且该关联在几个RBCS基因的启动子中保守。这种系统发育保守的启动子特征可能反映了一种常见的调节机制，并识别出光线和糖信号途径之间的收敛点。
Photosynthesis-associated nuclear genes (PhANGs) are able to respond to multiple environmental and developmental signals, including light, sugars and abscisic acid (ABA). PhANGs have been extensively studied at the level of transcriptional regulation and several cis-acting elements important for light responsiveness have been identified in their promoter sequences. However, the regulatory elements involved in sugar and ABA regulation of PhANGs have not been completely characterized. Using conserved modular arrangement 5 (CMA5), a previously characterized minimal light-responsive unit, we show that in Arabidopsis thaliana this unit responds not only positively to light signals, but also negatively to sugars and ABA. The latter responses were found to be impaired in the abi4 mutant, indicating that ABSCISIC ACID INSENSITIVE-4 (ABI4) is a regulator involved in sugar and ABA repression of this minimal regulatory unit. Furthermore, we report a new sequence element conserved in several rbcS promoters, herewith named S-box, which is important for the sugar and ABA responsiveness of CMA5. This sequence corresponds to a putative ABI4-binding site, which is in fact bound by the Arabidopsis ABI4 protein in vitro. The S-box is closely associated with the G-box present in CMA5, and this association is conserved in the promoters of several RBCS genes. This phylogenetically conserved promoter feature probably reflects a common regulatory mechanism and identifies a point of convergence between light- and sugar-signaling pathways.