RS domains contact splicing signals and promote splicing by a common mechanism in yeast through humans
RS domains contact splicing signals and promote splicing by a common mechanism in yeast through humans
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DOI：
10.1101/gad.1422106
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发表时间：
2006-07-01
影响因子：
10.5
通讯作者：
Green, Michael R.
中科院分区：
文献类型：
--
作者：
Shen, Haihong;Green, Michael R.
丝氨酸-精氨酸（SR）蛋白是后生动物常见的剪接因子，含有一个必需的富含丝氨酸（RS）结构域。我们以前已经发现哺乳动物剪接体的装配涉及RS结构域和两个剪接信号（分支点和5'剪接位点）之间的一系列顺序相互作用。在这里，我们研究RS域是如何被定向到专门接触剪接信号，以及这种相互作用如何促进剪接。酵母Saccharomyces cerevisiae缺乏SR蛋白。然而，我们表明，拴系一个哺乳动物RS域酵母肌动蛋白前mRNA拯救剪接的某些分支点或5'剪接位点突变体，其中U snRNA碱基配对已减少。相反，在哺乳动物前mRNA上，当剪接信号与U snRNA的互补性增加时，通常必需的SR蛋白变得不稳定。我们发现，在没有其他剪接因子的情况下，RS结构域栓系到前mRNA选择性地接触双链RNA区域，并增强RNA-RNA碱基配对。值得注意的是，所有这些活动都需要RS结构域的磷酸化。基于这些结果，我们提出RS域选择性地接触剪接信号，因为，由于瞬时U snRNA碱基配对，它们是部分双链的。RS结构域-剪接信号相互作用反过来促进（或稳定）U snRNA和前mRNA底物之间的碱基配对，从而增强剪接。我们的研究结果揭示了RS结构域功能在酵母中通过人类的共同机制。
Serine-arginine (SR) proteins are general metazoan splicing factors that contain an essential arginine-serine-rich (RS) domain. We have previously found that mammalian spliceosome assembly involves a series of sequential interactions between RS domains and two splicing signals: the branchpoint and the 5' splice site. Here we study how RS domains are directed to specifically contact splicing signals, and how this interaction promotes splicing. The yeast Saccharomyces cerevisiae lacks SR proteins. However, we show that tethering a mammalian RS domain to a yeast actin pre-mRNA rescues splicing of certain branchpoint or 5' splice site mutants in which U snRNA base-pairing has been decreased. Conversely, on a mammalian pre-mRNA, a normally essential SR protein becomes dispensable when the complementarity of a splicing signal to a U snRNA is increased. We find that in the absence of other splicing factors an RS domain tethered to a pre-mRNA selectively contacts a double-stranded RNA region and enhances RNA-RNA base-pairing. Significantly, all of these activities require phosphorylation of the RS domain. Based on these results, we propose that RS domains selectively contact splicing signals because, due to transient U snRNA base-pairing, they are partially double-stranded. The RS domain-splicing signal interaction, in turn, promotes (or stabilizes) base-pairing between the U snRNA and pre-mRNA substrate, thereby enhancing splicing. Our results reveal a common mechanism of RS domain function in yeast through humans.