A strong exonic splicing enhancer in dystrophin exon 19 achieve proper splicing without an upstream polypyrimidine tract
A strong exonic splicing enhancer in dystrophin exon 19 achieve proper splicing without an upstream polypyrimidine tract
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DOI：
10.1093/jb/mvm227
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发表时间：
2008-03-01
影响因子：
2.7
通讯作者：
Matsuo, Masafumi
中科院分区：
文献类型：
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作者：
Habara, Yasuaki;Doshita, Mari;Matsuo, Masafumi
已知正确的剪接是在位于外显子-内含子边界的保守顺式元件的控制下进行的。最近，研究表明，除了剪接供体和受体位点序列外，外显子剪接增强子（ESEs）等其他元件对于某些外显子的正确剪接是必不可少的；然而，这些顺式元素之间的关系尚不清楚。在本报告中，我们利用肌营养不良蛋白外显子19来分析ESE与其上游受体位点序列之间的关系。肌营养不良蛋白外显子19编码外显子剪接增强子（dyse - ese19）序列，维持适当的剪接供体和受体一致序列。利用HeLa细胞中表达的一个minigene报告基因进行剪接模式分析，结果表明，一个强聚嘧啶通道（PPT）或一个完全活性的dysese19足以实现正确的剪接。这两个顺式元件中的每一个都有足够的活性来进行正确的外显子19剪接，这表明当下游外显子含有强ESE时，PPT被认为是剪接必不可少的顺式元件。这种补偿只在活细胞中发现，而在“体外剪接”中没有发现。这表明先前使用体外剪接系统的剪接实验可能低估了ESEs的活性。
Proper splicing is known to proceed under the control of conserved cis-elements located at exon-intron boundaries. Recently, it was shown that additional elements, such as exonic splicing enhancers (ESEs), are essential for the proper splicing of certain exons, in addition to the splice donor and acceptor site sequences; however, the relationship between these cis-elements is still unclear. In this report, we utilize dystrophin exon 19 to analyse the relationship between the ESE and its upstream acceptor site sequences. Dystrophin exon 19, which maintains adequate splicing donor and acceptor consensus sequences, encodes exonic splicing enhancer (dys-ESE19) sequences. Splice pattern analysis, using a minigene reporter expressed in HeLa cells, showed that either a strong polypyrimidine tract (PPT) or a fully active dys-ESE19 is sufficient for proper splicing. Each of these two cis-elements has enough activity for proper exon 19 splicing suggesting that the PPT, which is believed to be an essential cis-element for splicing, is dispensable when the downstream exon contains a strong ESE. This compensation was only seen in living cells but not in 'in vitro splicing'. This suggests the possibility that the previous splicing experiments using an in vitro splicing system could underestimate the activity of ESEs.