Huang Bo, Jin Longguo, Liu Jin-Yuan
Laboratory of Molecular Biology and MOE Laboratory of Protein Science, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China.
J Plant Physiol. 2008 Feb;165(2):214-23. doi: 10.1016/j.jplph.2006.11.003. Epub 2007 Jan 16.
A cDNA encoding one novel DRE-binding protein, GhDBP2, was isolated from cotton seedlings. It is classified into the A-6 group of DREB subfamily based on multiple sequence alignment and phylogenetic characterization. Using semi-quantitative RT-PCR, we found that the GhDBP2 transcripts were greatly induced by drought, NaCl, low temperature and ABA treatments in cotton cotyledons. The DNA-binding properties of GhDBP2 were analyzed by electrophoretic mobility shift assay (EMSA), showing that GhDBP2 successfully binds to the previously characterized DRE cis-element as well as the promoter region of the LEA D113 gene. Consistent with its role as a DNA-binding protein, GhDBP2 is preferentially localized to the nucleus of onion epidermal cells. In addition, when GhDBP2 is transiently expressed in tobacco cells, it activates reporter gene expression driven by the LEA D113 promoter. Taken together, our results indicate that GhDBP2 is a DRE-binding transcriptional activator involved in activation of down-stream genes such as LEA D113 expression through interaction with the DRE element, in response to environmental stresses as well as ABA treatment.
从棉花幼苗中分离出一个编码新型DRE结合蛋白GhDBP2的cDNA。基于多序列比对和系统发育特征分析，它被归类为DREB亚家族的A-6组。通过半定量RT-PCR，我们发现GhDBP2转录本在棉花子叶中受到干旱、NaCl、低温和ABA处理的强烈诱导。通过电泳迁移率变动分析（EMSA）分析了GhDBP2的DNA结合特性，结果表明GhDBP2能够成功结合先前鉴定的DRE顺式元件以及LEA D113基因的启动子区域。与其作为DNA结合蛋白的作用一致，GhDBP2优先定位于洋葱表皮细胞的细胞核。此外，当GhDBP2在烟草细胞中瞬时表达时，它可激活由LEA D113启动子驱动的报告基因表达。综上所述，我们的结果表明，GhDBP2是一种DRE结合转录激活因子，通过与DRE元件相互作用，参与激活下游基因如LEA D113的表达，以响应环境胁迫和ABA处理。
