A functional interaction between the carboxy-terminal domain of RNA polymerase II and pre-mRNA splicing.
A functional interaction between the carboxy-terminal domain of RNA polymerase II and pre-mRNA splicing.
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DOI：
10.1083/jcb.136.1.5
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发表时间：
1997-01-13
期刊：
影响因子：
--
通讯作者：
Warren SL
中科院分区：
文献类型：
--
作者：
Du L;Warren SL
在之前的研究中，我们发现 Sm snRNP 和 SerArg (SR) 家族蛋白与含有过度磷酸化 CTD 的 Pol II 分子发生共免疫沉淀。 Pol IIo 和剪接因子之间的关联在前体 mRNA 不存在的情况下得以维持，并且聚合酶不需要参与转录。后一个发现使我们推测 CTD 的磷酸化形式与体内前 mRNA 剪接成分相互作用。为了验证这一想法，我们对一组嵌套的 CTD 衍生蛋白进行了分析，以确定其改变剪接因子核分布以及干扰体内剪接的能力。含有七肽 1-52 (CTD52)、1-32 (CTD32)、1-26 (CTD26)、1-13 (CTD13)、1-6 (CTD6)、1-3 (CTD3) 或 1 (CTD1) 的蛋白质在哺乳动物细胞中表达。 CTD 衍生的蛋白质在体内被磷酸化，并在细胞核中积累，尽管它们缺乏传统的核定位信号。 CTD52 诱导剪接因子从离散核结构域到弥散核质的选择性重组，并且显着地，它阻止剪接但不剪接的人 β-珠蛋白转录物的积累。剪接因子破坏的程度和剪接的抑制程度与添加到蛋白质中的七肽的数量成正比。上述结果表明Pol II 的CTD 和pre-mRNA 剪接之间存在功能性相互作用。
In the preceding study we found that Sm snRNPs and SerArg (SR) family proteins co-immunoprecipitate with Pol II molecules containing a hyperphosphorylated CTD. The association between Pol IIo and splicing factors is maintained in the absence of pre-mRNA, and the polymerase need not be transcriptionally engaged. The latter findings led us to hypothesize that a phosphorylated form of the CTD interacts with pre-mRNA splicing components in vivo. To test this idea, a nested set of CTD-derived proteins was assayed for the ability to alter the nuclear distribution of splicing factors, and to interfere with splicing in vivo. Proteins containing heptapeptides 1-52 (CTD52), 1-32 (CTD32), 1-26 (CTD26), 1-13 (CTD13), 1-6 (CTD6), 1-3 (CTD3), or 1 (CTD1) were expressed in mammalian cells. The CTD-derived proteins become phosphorylated in vivo, and accumulate in the nucleus even though they lack a conventional nuclear localization signal. CTD52 induces a selective reorganization of splicing factors from discrete nuclear domains to the diffuse nucleoplasm, and significantly, it blocks the accumulation of spliced, but not unspliced, human β-globin transcripts. The extent of splicing factor disruption, and the degree of inhibition of splicing, are proportional to the number of heptapeptides added to the protein. The above results indicate a functional interaction between Pol II's CTD and pre-mRNA splicing.