The Binding of Multiple Nuclear Receptors to a Single Regulatory Region Is Important for the Proper Expression of EDG84A in Drosophila melanogaster
The Binding of Multiple Nuclear Receptors to a Single Regulatory Region Is Important for the Proper Expression of EDG84A in Drosophila melanogaster
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DOI：
10.1016/j.jmb.2012.10.020
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发表时间：
2013-01-09
影响因子：
5.6
通讯作者：
Ueda, Hitoshi
中科院分区：
文献类型：
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作者：
Akagi, Kazutaka;Kageyama, Yuji;Ueda, Hitoshi
核受体转录因子家族成员具有靶序列相似性；然而，人们对这些因素如何发挥其具体的监管控制作用知之甚少。在这里，我们研究了调节果蝇 EDG84A 基因（孤儿核受体 β FTZ-F1 的靶基因）表达的机制，作为研究核受体之间合作行为的模型。我们发现三种核受体 β FTZ-F1、DHR3 和 DHR39 与 EDG84A 启动子中的共同元件结合。 EDG84A 启动子-lacZ 报告基因在 DHR39 诱导动物和突变动物中的表达水平分别表明 DHR39 作为阻遏物。携带阻止 DHR3 结合的突变的报告基因的活性在 ftz-f1 突变体中降低，并通过 β FTZ-F1 的诱导表达而恢复，表明 DHR3 和 β FTZ-F1 以冗余方式激活 EDG84A 基因。携带废除DHR39和FTZ-F1结合的突变的报告基因过早表达，并且携带阻止DHR3结合的突变的报告基因的表达水平降低。这些发现表明该基因的时间表达主要受 β FTZ-F1 控制，但 DHR3 的结合也很重要。果蝇物种间结合位点序列的比较表明，DHR3结合能力是在黑腹果蝇亚群进化后获得的，这种能力可能有助于该基因的稳健表达。这些结果显示了多个核受体利用复杂的调节机制通过单个靶位点正确调节其靶基因的表达。 (C) 2012 Elsevier Ltd. 保留所有权利。
Nuclear receptor transcription factor family members share target sequence similarity; however, little is known about how these factors exert their specific regulatory control. Here, we examine the mechanism regulating the expression of the Drosophila EDG84A gene, a target gene of the orphan nuclear receptor beta FTZ-F1, as a model to study the cooperative behavior among nuclear receptors. We show that the three nuclear receptors beta FTZ-F1, DHR3, and DHR39 bind to a common element in the EDG84A promoter. The expression level of the EDG84A promoter-lacZ reporter genes in DHR39-induced and mutant animals, respectively, suggests that DHR39 works as a repressor. The activity of a reporter gene carrying a mutation preventing DHR3 binding was reduced in ftz-f1 mutants and rescued by the induced expression of beta FTZ-F1, suggesting that DHR3 and beta FTZ-F1 activate the EDG84A gene in a redundant manner. A reporter gene carrying a mutation that abolishes DHR39 and FTZ-F1 binding was prematurely expressed, and the expression level of the reporter gene carrying a mutation preventing DHR3 binding was reduced. These findings suggest that the temporal expression of this gene is mainly controlled by beta FTZ-F1 but that the binding of DHR3 is also important. Comparison of the binding site sequence among Drosophila species suggests that DHR3 binding ability was gained after the melanogastersubgroup evolved, and this ability may contribute to the robust expression of this gene. These results show the complicated regulatory mechanisms utilized by multiple nuclear receptors to properly regulate the expression of their target gene through a single target site. (C) 2012 Elsevier Ltd. All rights reserved.