Kardish N, Magal N, Aviv D, Galun E
Department of Plant Genetics, Weizmann Institute of Science, Rehovot, Israel.
Plant Mol Biol. 1994 Aug;25(5):887-97. doi: 10.1007/BF00028883.
The chloroplastic Cu,Zn superoxide dismutase (SOD) has an important role in the defense against damage by oxygen radicals in the chloroplasts. Here, for the first time, we report on the isolation of a genomic DNA clone from tomato that contains all the coding sequence for the chloroplastic Cu,Zn SOD as well as a 442 bp DNA fragment upstream of the translational initiation site. The latter upstream sequence has a putative TATA box and a 285 bp promoter region, 5' of the apparent transcriptional initiation and a 157 bp leader region. The coding sequence is composed of 8 exons that are interspaced by 7 introns; we termed this gene SODCp;Le:1. The 442 bp fragment was cloned into a pBI101 vector, upstream of the uidA (GUS) gene, via transcriptional fusion. Agrobacterium-mediated transformation resulted in transgenic tobacco plants. The progeny (after self-pollination) of 14 transformed plants, which expressed GUS above a threshold of 1 nmol/min per mg protein, were found to fall into two distinct groups. In the seedlings of 10 lines (group A) GUS expression was enhanced by exposure to light. In 4 lines of this group maintenance for 3 days in the dark eliminated GUS activity. The seedlings of group B expressed GUS regardless of the light/dark regime. In plants of group A, GUS expression was also developmentally regulated: high GUS activity in young leaves, low activity in mature leaves and no activity in the roots. The results suggest that this short chloroplastic Cu,Zn SOD promoter contains motifs for developmental (spatial) regulation as well as motifs responsive to light (or to oxygen radicals resulting from light-driven photosynthesis).
叶绿体铜锌超氧化物歧化酶（SOD）在抵御叶绿体中氧自由基造成的损伤方面发挥着重要作用。在此，我们首次报道从番茄中分离出一个基因组DNA克隆，它包含叶绿体铜锌SOD的所有编码序列以及翻译起始位点上游442 bp的DNA片段。后者的上游序列有一个推定的TATA框和一个285 bp的启动子区域，位于明显转录起始位点的5'端以及一个157 bp的前导区域。编码序列由8个外显子组成，中间间隔7个内含子；我们将这个基因命名为SODCp;Le:1。通过转录融合将442 bp的片段克隆到pBI101载体中，位于uidA（GUS）基因的上游。农杆菌介导的转化产生了转基因烟草植株。14株转化植株（自花授粉后）的后代中，GUS表达量高于每毫克蛋白质1 nmol/分钟阈值的植株被发现分为两个不同的组。在10个株系（A组）的幼苗中，光照可增强GUS表达。在该组的4个株系中，黑暗中培养3天会消除GUS活性。B组的幼苗无论光照/黑暗条件如何均表达GUS。在A组植株中，GUS表达也受到发育调控：幼叶中GUS活性高，成熟叶中活性低，根中无活性。结果表明，这个短的叶绿体铜锌SOD启动子包含发育（空间）调控基序以及对光（或光驱动光合作用产生的氧自由基）响应的基序。
