Zhang B, Chen W, Foley R C, Büttner M, Singh K B
Department of Molecular, Cell, and Developmental Biology, University of California-Los Angeles 90095-1606, USA.
Plant Cell. 1995 Dec;7(12):2241-52. doi: 10.1105/tpc.7.12.2241.
Octopine synthase (ocs) elements are a group of promoter elements that have been exploited by plant pathogens to express genes in plants. ocs elements are components of the promoters of certain plant glutathione S-transferase genes and may function as oxidative stress response elements. Genes for ocs element binding factors (OBFs), which belong to a specific class of highly conserved, plant basic domain-leucine zipper transcription factors, have been isolated and include the Arabidopsis OBF4 and OBF5 genes. To characterize proteins that modulate the activity of the OBF proteins, we screened an Arabidopsis cDNA library with the labeled OBF4 protein and isolated OBP1 (for OBF binding protein). OBP1 contains a 51-amino acid domain that is highly conserved with two plant DNA binding proteins, which we refer to as the MOA domain. OBP1 is also a DNA binding protein and binds to the cauliflower mosaic virus 35S promoter at a site distinct from the ocs element in the 35S promoter. OBP1 specifically increased the binding of the OBF proteins to ocs element sequences, raising the possibility that interactions between these proteins are important for the activity of the 35S promoter.
章鱼碱合酶（ocs）元件是一类启动子元件，已被植物病原体利用来在植物中表达基因。ocs元件是某些植物谷胱甘肽S-转移酶基因启动子的组成部分，可能作为氧化应激反应元件发挥作用。属于一类高度保守的植物碱性结构域-亮氨酸拉链转录因子的ocs元件结合因子（OBF）基因已被分离出来，包括拟南芥OBF4和OBF5基因。为了鉴定调节OBF蛋白活性的蛋白质，我们用标记的OBF4蛋白筛选了拟南芥cDNA文库，并分离出OBP1（OBF结合蛋白）。OBP1包含一个51个氨基酸的结构域，该结构域与两种植物DNA结合蛋白高度保守，我们将其称为MOA结构域。OBP1也是一种DNA结合蛋白，它在与35S启动子中ocs元件不同的位点与花椰菜花叶病毒35S启动子结合。OBP1特异性地增加了OBF蛋白与ocs元件序列的结合，这增加了这些蛋白之间的相互作用对35S启动子活性很重要的可能性。
