Wheat Dof transcription factor WPBF interacts with TaQM and activates transcription of an alpha-gliadin gene during wheat seed development
Wheat Dof transcription factor WPBF interacts with TaQM and activates transcription of an alpha-gliadin gene during wheat seed development
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DOI：
10.1007/s11103-006-9073-3
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发表时间：
2007-01-01
影响因子：
5.1
通讯作者：
Sun, Qixin
中科院分区：
文献类型：
--
作者：
Dong, Guoqing;Ni, Zhongfu;Sun, Qixin
小麦醇溶谷蛋白盒结合因子（WPBF）是一种先前从小麦胚乳中分离到的DOF转录因子，在种子发育过程中可能是醇溶谷蛋白基因表达的激活因子。在这项研究中，我们表明，WPBF的表达在所有的小麦组织分析，和蛋白质，TaQM，确定从小麦根cDNA文库，与Dof域的WPBF。Pull-down实验和双分子荧光互补（BiFC）实验证实了WPBF与TaQM的特异性相互作用。TaQM基因的表达模式与WPBF相似。在细菌中表达的GST-WPBF结合醇溶谷蛋白盒（PB）5 ′-TGTAAAG-3 ′，其来源于编码贮藏蛋白的天然α-麦醇溶蛋白基因的启动子区。在共转染BY-2原生质体细胞中的瞬时表达实验表明，WPBF通过与完整的PB结合来反式激活天然α-麦醇溶蛋白启动子的转录。当WPBF和TaQM共转染时，α-麦醇溶蛋白基因的转录活性比WPBF单独转染时高6倍。此外，在转基因拟南芥的种子和维管系统中观察到WPBF基因的启动子活性，这与WPBF基因在小麦中的表达谱一致。因此，我们认为WPBF不仅在小麦种子发育过程中起作用，而且在其他生长发育过程中也起作用。
Wheat prolamin-box binding factor (WPBF), a DOF transcription factor previously was isolated from wheat endosperm and suggested to function as an activator of prolamin gene expression during seed development. In this study, we showed that WPBF is expressed in all wheat tissues analyzed, and a protein, TaQM, was identified from a wheat root cDNA library, to interact with the Dof domain of WPBF. The specific interaction between WPBF and TaQM was confirmed by pull-down assay and bimolecular fluorescence complementation (BiFC) experiment. The expression patterns of TaQM gene are similar with that of WPBF. The GST-WPBF expressed in bacteria binds the Prolamin box (PB) 5'-TGTAAAG-3', derived from the promoter region of a native alpha-gliadin gene encoding a storage protein. Transient expression experiments in co-transfected BY-2 protoplast cells demonstrated that WPBF trans-activated transcription from native alpha-gliadin promoter through binding to the intact PB. When WPBF and TaQM are co-transfected together the transcription activity of alpha-gliadin gene was six-fold higher than when WPBF was transfected alone. Furthermore, the promoter activities of WPBF gene were observed in the seeds and the vascular system of transgenic Arabidopsis, which was identical to the expression profiles of WPBF in wheat. Hence, we proposed that WPBF functions not only during wheat seed development but also during other growth and development processes.