D'Avino P P, Crispi S, Cherbas L, Cherbas P, Furia M
Dipartimento di Genetica, Biologia Generale e Molecolare, Università di Napoli, Italy.
Mol Cell Endocrinol. 1995 Aug 30;113(1):1-9. doi: 10.1016/0303-7207(95)03584-t.
In Drosophila melanogaster, three temporally distinct ecdysone-responsive puff sets, the so-called intermoult, early and late puffs, have been described on the salivary gland polytene chromosomes. We have analyzed in detail a DNA segment of the 3C polytene region, from which the originates one of the most prominent intermoult puffs, with the aim of identifying ecdysone response elements (EcREs). Here we report that two putative EcREs of identical sequence are located at this puff site. Interestingly, these elements display a novel structural feature, being composed of directly repeated half-sites. Our results show that the EcR/USP heterodimer known to constitute the ecdysone functional receptor complex is able to bind to and transactivate through target elements composed of directly repeated half-sites. In addition, we show that these elements are also able to bind efficiently USP alone, suggesting that USP and EcR/USP could compete for their binding to DNA.
在黑腹果蝇的唾液腺多线染色体上，已描述了三种在时间上不同的蜕皮激素反应性胀泡组，即所谓的蜕皮间期、早期和晚期胀泡。我们详细分析了3C多线区域的一个DNA片段，最显著的蜕皮间期胀泡之一由此产生，目的是鉴定蜕皮激素反应元件（EcREs）。在此我们报告，两个序列相同的假定EcREs位于这个胀泡位点。有趣的是，这些元件呈现出一种新的结构特征，由直接重复的半位点组成。我们的结果表明，已知构成蜕皮激素功能受体复合物的EcR/USP异二聚体能够与由直接重复半位点组成的靶元件结合并通过其进行反式激活。此外，我们表明这些元件也能够单独有效地结合USP，这表明USP和EcR/USP可能会竞争与DNA的结合。
