Research resource: expression profiling reveals unexpected targets and functions of the human steroid receptor RNA activator (SRA) gene.
Research resource: expression profiling reveals unexpected targets and functions of the human steroid receptor RNA activator (SRA) gene.
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DOI：
10.1210/me.2009-0427
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发表时间：
2010-05-01
期刊：
影响因子：
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通讯作者：
O'Malley, Bert W
中科院分区：
文献类型：
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作者：
Foulds, Charles E;Tsimelzon, Anna;O'Malley, Bert W
人类类固醇受体RNA激活因子（SRA）基因编码非编码RNA （ncRNAs）和产生蛋白质的亚型。在报告基因试验中，SRA ncRNA增强核受体和MyoD介导的转录，但也参与特定的辅抑制因子复合物，作为一种独特的支架。据报道，SRA RNA水平可能影响一些生物学功能，如增殖、凋亡、类固醇生成和肌肉生成。然而，SRA rna可能调控的内源性靶基因的广度在很大程度上仍然未知。为了解决这个问题，我们用小干扰RNA在两种人类癌细胞系中耗尽SRA RNA，然后通过微阵列分析检测基因表达的变化。大多数显著改变的基因在SRA敲低后减少，这表明SRA rna是内源性共激活因子。出乎意料的是，在雌二醇处理的MCF-7细胞中，只有一小部分雌激素受体- α直接靶基因受到影响。鉴定出8个真正的SRA下游靶基因（SLC2A3、SLC2A12、CCL20、TGFB2、DIO2、TMEM65、TBL1X和TMPRSS2），代表了除TMPRSS2外的全新SRA靶点。这些数据表明SRA在葡萄糖摄取、细胞信号传导、T(3)激素产生和侵袭/转移中发挥了意想不到的作用。MDA-MB-231细胞中SRA的缺失降低了对这一过程至关重要的一些基因的侵袭性和表达。与敲低数据一致，过表达的SRA ncRNA协同激活某些目标启动子，并可能增强一些协调节蛋白的活性。这项研究是一个有价值的资源，因为它代表了哺乳动物RNA共调节因子的第一个全基因组分析。
The human steroid receptor RNA activator (SRA) gene encodes both noncoding RNAs (ncRNAs) and protein-generating isoforms. In reporter assays, SRA ncRNA enhances nuclear receptor and myogenic differentiation 1 (MyoD)-mediated transcription but also participates in specific corepressor complexes, serving as a distinct scaffold. That SRA RNA levels might affect some biological functions, such as proliferation, apoptosis, steroidogenesis, and myogenesis, has been reported. However, the breadth of endogenous target genes that might be regulated by SRA RNAs remains largely unknown. To address this, we depleted SRA RNA in two human cancer cell lines with small interfering RNAs and then assayed for changes in gene expression by microarray analyses. The majority of significantly changed genes were reduced upon SRA knockdown, implicating SRA RNAs as endogenous coactivators. Unexpectedly, only a small subset of direct estrogen receptor-alpha target genes was affected in estradiol-treated MCF-7 cells. Eight bona fide SRA downstream target genes were identified (SLC2A3, SLC2A12, CCL20, TGFB2, DIO2, TMEM65, TBL1X, and TMPRSS2), representing entirely novel SRA targets, except for TMPRSS2. These data suggest unanticipated roles for SRA in glucose uptake, cellular signaling, T(3) hormone generation, and invasion/metastasis. SRA depletion in MDA-MB-231 cells reduced invasiveness and expression of some genes critical for this process. Consistent with the knockdown data, overexpressed SRA ncRNA coactivates certain target promoters and may enhance the activity of some coregulatory proteins. This study is a valuable resource because it represents the first genome-wide analysis of a mammalian RNA coregulator.