Saleh Abdelaty, Lumbreras Victoria, Lopez Cristina, Dominguez-Puigjaner Eva, Kizis Dimosthenis, Pagès Montserrat
Departamento de Genética Molecular, Instituto de Biología Molecular de Barcelona, IBMB, Consejo Superior de Investigaciones Científicas, CSIC, 18-26 Jordi Girona, 08034 Barcelona, Spain.
Plant J. 2006 Jun;46(5):747-57. doi: 10.1111/j.1365-313X.2006.02742.x.
The maize dehydration-responsive element (DRE)-binding factor, DBF1, is a member of the Apetala 2/Ethylene Response Factor transcription factors family and is involved in the regulation of the ABA-responsive gene rab17 through the DRE in an ABA-dependent pathway. In this study we analysed the functionality of DBF1 in abiotic stress responses and found that Arabidopsis plants over-expressing DBF1 were more tolerant to osmotic stress than control plants. In yeast two-hybrid analyses, DBF1 interacted with DBF1-interactor protein 1 (DIP1), a protein containing a conserved R3H single-strand DNA-binding domain. Subcellular localization of DIP1 showed that the protein fusion DIP1-Red Flourescent Protein (RFP) was mainly localized in the cytoplasm. However, after co-transformation of DBF1-GFP and DIP1-RFP, both proteins co-localized in the nucleus. Interestingly, when the N-terminal DBF1-GFP was co-expressed with DIP1-RFP, both proteins co-localized predominantly in the cytoplasmic speckles observed for N-terminal DBF1-GFP fusion protein. These results clearly show in vivo interaction of DBF1 with DIP1 in the cell and that this interaction is necessary for the nuclear localization of DIP1 protein. Analysis of the regulatory effect of the DBF1 and DIP1 interaction on the maize rab17 promoter activity indicated that co-transfection of DBF1 with DIP1 enhances promoter activity in the absence of ABA treatment. We suggest that the regulated association of DBF1 and DIP1 may control the levels of target gene expression during stress conditions.
玉米脱水响应元件（DRE）结合因子DBF1是AP2/乙烯响应因子转录因子家族的成员，通过依赖脱落酸（ABA）的途径，参与调控ABA响应基因rab17。在本研究中，我们分析了DBF1在非生物胁迫响应中的功能，发现过表达DBF1的拟南芥植株比对照植株更耐渗透胁迫。在酵母双杂交分析中，DBF1与DBF1相互作用蛋白1（DIP1）相互作用，DIP1是一种含有保守R3H单链DNA结合结构域的蛋白质。DIP1的亚细胞定位显示，蛋白质融合体DIP1-红色荧光蛋白（RFP）主要定位于细胞质中。然而，在共转化DBF1-GFP和DIP1-RFP后，两种蛋白共定位于细胞核中。有趣的是，当N端DBF1-GFP与DIP1-RFP共表达时，两种蛋白主要共定位于在N端DBF1-GFP融合蛋白中观察到的细胞质斑点中。这些结果清楚地表明DBF1与DIP1在细胞内存在体内相互作用，并且这种相互作用对于DIP1蛋白的核定位是必需的。对DBF1与DIP1相互作用对玉米rab17启动子活性的调控作用分析表明，在没有ABA处理的情况下，DBF1与DIP1共转染可增强启动子活性。我们认为，DBF1与DIP1的调控关联可能在胁迫条件下控制靶基因的表达水平。
