Biotechnology Research Institute, Chinese Academy Agricultural Sciences, MOA Key Laboratory on Safety Assessment (Molecular) of Agri-GMO, Beijing 100081, China.
Inner Mongolia Key Laboratory of Herbage & Endemic Crop Biotechnology/College of Life Sciences, Inner Mongolia University, Hohhot 010021, China.
Int J Mol Sci. 2018 Oct 23;19(11):3291. doi: 10.3390/ijms19113291.
Stacked traits have become an important trend in the current development of genomically modified crops. The bidirectional promoter can not only prevent the co-suppression of multigene expression, but also increase the efficiency of the cultivation of transgenic plants with multigenes. In , and are head-to-head gene pairs located on chromosome D09. We cloned the 1429-bp intergenic region between the and genes from . The cloned DNA fragment GhZU had the characteristics of a bidirectional promoter, with 38.7% G+C content, three CpG islands and no TATA-box. Using and as reporter genes, a series of expression vectors were constructed into young leaves of tobacco. The histochemical GUS (Beta-glucuronidase) assay and GFP (green fluorescence protein) detection results indicated that GhZU could drive the expression of the reporter genes and simultaneously in both orientations. Furthermore, we transformed the expression vectors into and found that GUS was concentrated at vigorous growth sites, such as the leaf tip, the base of the leaves and pod, and the stigma. GFP was also mainly expressed in the epidermis of young leaves. In summary, we determined that the intergenic region GhZU was an orientation-dependent bidirectional promoter, and this is the first report on the bidirectional promoter from . Our findings in this study are likely to enhance understanding on the regulatory mechanisms of plant bidirectional promoters.
堆叠性状已成为当前转基因作物基因组学发展的一个重要趋势。双向启动子不仅可以防止多基因表达的共抑制，还可以提高多基因转基因植物的培养效率。在 、 和 中， 是位于染色体 D09 上的头对头基因对。我们从 中克隆了 基因对之间的 1429bp 基因间区。克隆的 DNA 片段 GhZU 具有双向启动子的特征，G+C 含量为 38.7%，有三个 CpG 岛但没有 TATA 盒。使用 和 作为报告基因，我们将一系列表达载体构建到烟草的幼叶中。组织化学 GUS（β-葡萄糖醛酸酶）分析和 GFP（绿色荧光蛋白）检测结果表明，GhZU 可以同时以两个方向驱动报告基因 和 的表达。此外，我们将表达载体转化到 中，发现 GUS 集中在生长旺盛的部位，如叶尖、叶片基部和豆荚，以及柱头。GFP 也主要在幼叶的表皮中表达。总之，我们确定基因间区 GhZU 是一个具有方向性的双向启动子，这是首次从 中报道的双向启动子。我们在这项研究中的发现可能有助于增强对植物双向启动子调控机制的理解。
