Suhr S T, Gil E B, Senut M C, Gage F H
Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
Proc Natl Acad Sci U S A. 1998 Jul 7;95(14):7999-8004. doi: 10.1073/pnas.95.14.7999.
Our studies of the Bombyx mori ecdysone receptor (BE) revealed that, unlike the Drosophila melanogaster ecdysone receptor (DE), treatment of BE with the ecdysone agonist tebufenozide stimulated high level transactivation in mammalian cells without adding an exogenous heterodimer partner. Gel mobility shift and transfection assays with both the ultraspiracle gene product (Usp) and retinoid X receptor heterodimer partners indicated that this property of BE stems from significantly augmented heterodimer complex formation and concomitant DNA binding. We have mapped this "gain of function" to determinants within the D and E domains of BE and demonstrated that, although the D domain determinant is sufficient for high affinity heterodimerization with Usp, both determinants are necessary for high affinity interaction with retinoid X receptor. Modified BE receptors alone used as replication-defective retroviruses potently stimulated separate "reporter" viruses in all cell types examined, suggesting that BE has potentially broad utility in the modulation of transgene expression in mammalian cells.
我们对家蚕蜕皮激素受体（BE）的研究表明，与黑腹果蝇蜕皮激素受体（DE）不同，用蜕皮激素激动剂虫酰肼处理BE时，无需添加外源性异二聚体伴侣，就能在哺乳动物细胞中刺激高水平的反式激活。对超气门基因产物（Usp）和视黄酸X受体异二聚体伴侣进行凝胶迁移率变动分析和转染分析表明，BE的这一特性源于异二聚体复合物形成显著增加以及随之而来的DNA结合。我们已将这种“功能获得”定位到BE的D和E结构域内的决定因素，并证明，虽然D结构域决定因素足以与Usp进行高亲和力异二聚化，但两个决定因素对于与视黄酸X受体进行高亲和力相互作用都是必需的。单独用作复制缺陷型逆转录病毒的修饰BE受体在所有检测的细胞类型中均能有效刺激单独的“报告”病毒，这表明BE在调节哺乳动物细胞中的转基因表达方面具有潜在的广泛用途。
