Interactions of ultraspiracle with ecdysone receptor in the transduction of ecdysone- and juvenile hormone-signaling
Interactions of ultraspiracle with ecdysone receptor in the transduction of ecdysone- and juvenile hormone-signaling
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DOI：
10.1111/j.1742-4658.2005.04578.x
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发表时间：
2005-04-01
期刊：
影响因子：
5.4
通讯作者：
Jones, G
中科院分区：
文献类型：
--
作者：
Fang, F;Xu, Y;Jones, G
通过脊椎动物核激素受体整合两种激素信号的分析，其中类维生素A X受体是一个伴侣，产生了许多机制模型，包括那些描述为“从属”模型，其中一个伴侣的配体激活从属于另一个伴侣的配体状态。然而，两种激素信号通过无脊椎动物的核膜结合受体整合的机制迄今尚未得到实验阐明。本报告调查的整合无脊椎动物保幼激素（JH）和20-OH蜕皮激素（20 OHE）的信号水平上确定的核受体（ultraspiracle和蜕皮激素受体），转录激活一个定义的模型核心启动子（JH酯酶基因），通过指定的激素反应元件（DR 1和IR 1）。将JH III或20 OHE应用于用DR 1 JHECoreLuciferase（或IR 1 JHECoreLuciferase）报告基因启动子转染的培养的Sf 9细胞，各自诱导报告基因的表达。共处理的转染细胞与两种激素产生了更大的加性效应的转录，特别是IR 1 JHECoreLuciferase报告。在Sf 9细胞中的重组果蝇超气门（dUSP）的过表达促进形成dUSP寡聚体（潜在的同源二聚体），通过共免疫沉淀试验和电泳迁移率测定（EMSA）的DR 1探针，也增加了转录水平响应JH III，但没有增加转录响应单独的20 OHE治疗或两种激素一起。不适当的，过表达重组D.转染细胞中的黑腹蜕皮激素受体（dEcR）产生dUSP/dEcR异源二聚体[通过DR 1探针上的EMSA（supershift）测量]并增加对单独20 OHE处理的转录应答，但不增加对单独JH III处理的转录应答。我们的研究提供的证据表明，在这个模型系统中，JH III-激活的报告启动子是通过USP寡聚体（同二聚体），不含EcR，而20 OHE-激活是通过USP/EcR异二聚体。这些结果还表明，JH III和20 OHE信号转导的整合是通过USP/EcR异源二聚体，但当EcR配偶体未配体化时，该系统中的USP配偶体不能抑制JH III-活化。
Analyses of integration of two-hormone signaling through the vertebrate nuclear hormone receptors, for which the retinoid X receptor is one partner, have generated a number of mechanistic models, including those described as 'subordination' models wherein ligand-activation of one partner is subordinate to the liganded state of the other partner. However, mechanisms by which two-hormone signaling is integrated through invertebrate nuclear hormone-binding receptors has not been heretofore experimentally elucidated. This report investigates the integration of signaling of invertebrate juvenile hormone (JH) and 20-OH ecdysone (20OHE) at the level of identified nuclear receptors (ultraspiracle and ecdysone receptor), which transcriptionally activate a defined model core promoter (JH esterase gene), through specified hormone response elements (DR1 and IR1). Application of JH III, or 20OHE, to cultured Sf9 cells transfected with a DR1JHECoreLuciferase (or IR1JHECoreLuciferase) reporter promoter each induced expression of the reporter. Cotreatment of transfected cells with both hormones yielded a greater than additive effect on transcription, for especially the IR1JHECoreLuciferase reporter. Overexpression in Sf9 cells of recombinant Drosophila melanogaster ultraspiracle (dUSP) fostered formation of dUSP oligomer (potentially homodimer), as measured by coimmunoprecipitation assay and electrophoretic mobility assay (EMSA) on a DR1 probe, and also increased the level of transcription in response to JH III, but did not increase the transcriptional response to either 20OHE treatment alone or to the two hormones together. Inapposite, overexpression of recombinant D. melanogaster ecdysone receptor (dEcR) in the transfected cells generated dUSP/dEcR heterodimer [as measured by EMSA (supershift) on a DR1 probe] and increased the transcriptional response to 20OHE-alone treatment, but did not increase the transcriptional response to the JH III-alone treatment. Our studies provide evidence that in this model system, JH III-activation of the reporter promoter is through USP oligomer (homodimer) that does not contain EcR, while the 20OHE-activation is through the USP/EcR heterodimer. These results also show that the integration of JH III and 20OHE signaling is through the USP/EcR heterodimer, but that when the EcR partner is unliganded, the USP partner in this system is unable to transduce the JH III-activation.