National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi-110067, India.
Genomics. 2012 Oct;100(4):252-63. doi: 10.1016/j.ygeno.2012.06.012. Epub 2012 Jul 4.
A differentially expressed transcript, encoding a putative WD protein (Setaria italica WD40; SiWD40), was identified in foxtail millet. Tertiary structure modeling revealed that its C-terminus possesses eight blade β-propeller architecture. Its N-terminal has three α-helices and two 3(10)-helices and was highly induced by different abiotic stresses. The SiWD40:GFP fusion protein was nuclear localized. Promoter analysis showed the presence of many cis-acting elements, including two dehydration responsive elements (DRE). A stress-responsive SiAP2 domain containing protein could specifically bind to these elements in the SiWD40 promoter. Thus, for the first time, we report that DREs probably regulate expression of SiWD40 during environmental stress. Molecular docking analysis revealed that the circumference of the β-propeller structure was involved in an interaction with a SiCullin4 protein, supporting the adaptability of SiWD40 to act as a scaffold. Our study thus provides a vital clue for near future research on the stress-regulation of WD proteins.
在谷子中鉴定到一个差异表达的转录本，其编码一个假定的 WD 蛋白（Setaria italica WD40；SiWD40）。三级结构建模表明其 C 端具有八个叶片β-发夹结构。其 N 端有三个α-螺旋和两个 3（10）-螺旋，并且受到多种非生物胁迫的高度诱导。SiWD40:GFP 融合蛋白定位于核内。启动子分析表明存在许多顺式作用元件，包括两个脱水响应元件（DRE）。一个具有应激反应的 SiAP2 结构域包含蛋白可以特异性结合 SiWD40 启动子中的这些元件。因此，我们首次报道 DRE 可能在环境胁迫下调节 SiWD40 的表达。分子对接分析表明，β-发夹结构的圆周参与与一个 SiCullin4 蛋白的相互作用，支持 SiWD40 作为支架发挥作用的适应性。因此，我们的研究为未来 WD 蛋白的应激调节研究提供了重要线索。
