Tang Mingjuan, Sun Jingwen, Liu Yun, Chen Fan, Shen Shihua
Key Laboratory of Photosynthesis & Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, P.R. China.
Plant Mol Biol. 2007 Feb;63(3):419-28. doi: 10.1007/s11103-006-9098-7. Epub 2006 Nov 11.
A cDNA clone, named JcERF, was isolated from Jatropha curcas seedlings (a woody oil plant). It was classified as an ERF subfamily member based on multiple sequence alignment and phylogenetic characterization. The deduced amino acid sequences of the JcERF clone showed no significant sequence similarity with other known ERF proteins except for the conserved AP2/EREBP DNA-binding domain. Expression of the JcERF gene was rapidly induced upon salinity, drought, ethylene and mechanical wounding treatments. No significant changes in the JcERF expression were observed under ABA stress. Gel retardation assay revealed that the JcERF protein could bind specifically to the GCC box as well as to the C/DRE motif. Also it can be inferred from the gel-shift that there is a possibility that the near sequence of the GCC box has an important effect on the DNA-binding activity. In yeast, the JcERF protein specifically bound to the DRE sequence and activated the transcription of two reporter genes His3 and LacZ driven by the DRE sequence. When fused to the LexA DNA-binding domain, the full-length JcERF functioned effectively as a trans-activator in the yeast one-hybrid assay. Overexpression of JcERF cDNA in transgenic Arabidopsis enhanced the salt and freezing tolerance. Meanwhile the seed germination of JcERF transgenic plants was not affected by various concentrations ABA in MS medium. Taken together, the results showed that JcERF functioned as a novel transcription factor and it exhibited a mechanism of plant response to environmental factors like the other AP2/EREBP regulons that also exist in tropical woody plants.
从麻疯树（一种木本油料植物）幼苗中分离出一个名为JcERF的cDNA克隆。基于多序列比对和系统发育特征分析，它被归类为ERF亚家族成员。JcERF克隆推导的氨基酸序列，除了保守的AP2/EREBP DNA结合域外，与其他已知的ERF蛋白没有显著的序列相似性。在盐胁迫、干旱、乙烯和机械损伤处理后，JcERF基因的表达迅速被诱导。在ABA胁迫下，未观察到JcERF表达的显著变化。凝胶阻滞分析表明，JcERF蛋白可以特异性地结合GCC盒以及C/DRE基序。从凝胶迁移实验还可以推断，GCC盒的近序列可能对DNA结合活性有重要影响。在酵母中，JcERF蛋白特异性地结合DRE序列，并激活由DRE序列驱动的两个报告基因His3和LacZ的转录。当与LexA DNA结合域融合时，全长JcERF在酵母单杂交实验中有效地作为反式激活因子发挥作用。在转基因拟南芥中过表达JcERF cDNA增强了其耐盐性和抗冻性。同时，JcERF转基因植物的种子萌发不受MS培养基中不同浓度ABA的影响。综上所述，结果表明JcERF作为一种新型转录因子发挥作用，并且它表现出一种植物对环境因子的响应机制，类似于热带木本植物中也存在的其他AP2/EREBP调控子。
