Norre Frédéric, Peyrot Corinne, Garcia Christian, Rancé Iann, Drevet Joel, Theisen Manfred, Gruber Véronique
MERISTEM Therapeutics, Clermont-Ferrand, France.
Plant Mol Biol. 2002 Nov;50(4-5):699-712. doi: 10.1023/a:1019953914467.
The proximal region of the high-molecular-weight glutenin promoter of the Dx5 gene (PrHMWG-Dx5) carries an atypical bifactorial endosperm box containing two cis-acting elements, namely a G-box like motif followed by a prolamin-box motif (Pb1). Transient expression assays in maize endosperm indicate that a promoter fragment containing at least the G-box like element is necessary and sufficient for maximal expression of the HMWG-Dx5 promoter. In transformed maize, we have shown that a 89 bp sequence bearing the bifactorial endosperm box behaves like a functional cis-acting unit. Its repetition in tandem confers a strong specific additive effect specifically in endosperm tissue. In contrast, the fusion of the activation sequences 1 (as-1) and 2 (as-2) of the cauliflower mosaic virus (CaMV) 35S promoter with HMWG-Dx5 derived promoter sequences deregulates its activity in transformed maize. By gel mobility shift assays we have demonstrated that the G-box like motif may alternatively bind two protein groups which have the same DNA-binding affinities as the transcription factors of either the Opaque2 (O2) family and/or the ASF-1 family.
Dx5基因高分子量谷蛋白启动子（PrHMWG-Dx5）的近端区域带有一个非典型双因子胚乳盒，其中包含两个顺式作用元件，即一个类似G盒的基序，后面跟着一个醇溶蛋白盒基序（Pb1）。在玉米胚乳中的瞬时表达分析表明，一个至少包含类似G盒元件的启动子片段对于HMWG-Dx5启动子的最大表达是必要且充分的。在转基因玉米中，我们已经表明，带有双因子胚乳盒的89 bp序列表现为一个功能性顺式作用单元。其串联重复在胚乳组织中赋予强烈的特异性加性效应。相反，花椰菜花叶病毒（CaMV）35S启动子的激活序列1（as-1）和2（as-2）与HMWG-Dx5衍生的启动子序列融合会使其在转基因玉米中的活性失调。通过凝胶迁移率变动分析，我们已经证明类似G盒的基序可能交替结合两个蛋白质组，它们与不透明2（O2）家族和/或ASF-1家族的转录因子具有相同的DNA结合亲和力。
