Cotranscriptional splicing potentiates the mRNA production from a subset of estradiol-stimulated genes
Cotranscriptional splicing potentiates the mRNA production from a subset of estradiol-stimulated genes
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DOI：
10.1128/mcb.02231-07
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发表时间：
2008-09-01
影响因子：
5.3
通讯作者：
Auboeuf, Didier
中科院分区：
文献类型：
--
作者：
Bittencourt, Danielle;Dutertre, Martin;Auboeuf, Didier
虽然已知基因表达的早期步骤，如转录预起始，通常是限速的，并受到类固醇激素等刺激的调节，但下游步骤，包括剪接，对mRNA产生速率的潜在影响尚不清楚。在这项工作中，我们研究了转录刺激雌二醇对细胞周期蛋白D1， PS2和c-fos基因表达的影响，通过测量DNA模板上的RNA聚合酶II的水平，RNA聚合酶II相关的新生转录物的水平，以及未剪接，部分剪接和完全剪接的RNA的水平。我们证明，与PS2相比，cyclin D1的第一个内含子的共转录剪接效率更高，并增强了cyclin D1 mRNA的产生速率。共转录剪接的机制取决于基因5'端RNA聚合酶II的丝氨酸5磷酸化水平和CBP80的募集，CBP80是帽结合复合物的两个亚基之一，可以刺激启动子-近端内含子的剪接。我们的数据表明，由雌二醇刺激的基因子集（如细胞周期蛋白D1）产生的mRNA可以在一个非常有效的“装配线”中发生。相比之下，我们首次证明，尽管PS2基因具有强烈的转录激活作用，但由于低效率的共转录RNA加工，mRNA的产生并未优化。
While early steps of gene expression, such as transcription preinitiation, are known to often be rate limiting and to be regulated by such stimuli as steroid hormones, the potential impact of downstream steps, including splicing, on the mRNA production rate is unknown. In this work, we studied the effects of the transcriptional stimulus estradiol on cyclin D1, PS2, and c-fos gene expression by measuring the levels of RNA polymerase II on the DNA templates, the levels of nascent transcripts associated with RNA polymerase II, and the levels of unspliced, partially spliced, and fully spliced RNAs. We demonstrated that the efficiency of cotranscriptional splicing of the first intron was higher in the case of cyclin D1 than with PS2 and potentiated the cyclin D1 mRNA production rate. The mechanism involved in cotranscriptional splicing depended on the level of serine 5 phosphorylation of RNA polymerase II at the gene 5' end and on the recruitment of CBP80, one of the two subunits of the cap binding complex, which stimulates splicing of the promoter-proximal intron. Our data indicate that mRNA production from a subset of estradiol-stimulated genes, such as cyclin D1, could occur in a very efficient "assembly line." In contrast, we demonstrated for the first time that despite a strong transcriptional activation of the PS2 gene, the production of mRNA is not optimized owing to inefficient cotranscriptional RNA processing.