snRNA 3' end formation: the dawn of the Integrator complex.
snRNA 3' end formation: the dawn of the Integrator complex.
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DOI：
10.1042/bst0381082
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发表时间：
2010-08
影响因子：
3.9
通讯作者：
Wagner EJ
中科院分区：
文献类型：
--
作者：
Chen J;Wagner EJ
普遍表达的富含尿苷的 snRNA（小核 RNA）对于内含子的去除、组蛋白 mRNA 的正确表达和核糖体 RNA 的生物合成至关重要。关于它们组装成 snRNP（小核核糖核蛋白）颗粒及其在其他基因表达中的最终功能，人们已经了解很多；然而，相比之下，人们对这些关键非编码 RNA 的生物合成知之甚少。 snRNA 3' 端形成所需的序列元件已被鉴定，有趣的是，snRNA 的加工独特地依赖于 snRNA 启动子，这表明共转录加工很重要。然而，介导 snRNA 加工的反式作用 RNA 加工因子仍然难以捉摸，阻碍了整体进展。最近，参与这一过程的因子被生化纯化，并命名为积分复合体。自从最初发现以来，整合蛋白不仅与 snRNA 的产生有关，而且还与可能独立于 snRNA 生物发生的其他细胞过程有关。在本研究中，我们讨论 snRNA 生物合成和整合蛋白的作用。我们比较了不同类别的 RNA 聚合酶 II 转录物的 3' 末端形成模型，并制定/提出了 snRNA 生物发生中的整合器功能模型。
The ubiquitously expressed uridine-rich snRNAs (small nuclear RNAs) are essential for the removal of introns, proper expression of histone mRNA and biosynthesis of ribosomal RNA. Much is known about their assembly into snRNP (small nuclear ribonucleoprotein) particles and their ultimate function in the expression of other genes; however, in comparison, less is known about the biosynthesis of these critical non-coding RNAs. The sequence elements necessary for 3′ end formation of snRNAs have been identified and, intriguingly, the processing of snRNAs is uniquely dependent on the snRNA promoter, indicating that co-transcriptional processing is important. However, the trans-acting RNA-processing factors that mediate snRNA processing remained elusive, hindering overall progress. Recently, the factors involved in this process were biochemically purified, and designated the Integrator complex. Since their initial discovery, Integrator proteins have been implicated not only in the production of snRNA, but also in other cellular processes that may be independent of snRNA biogenesis. In the present study, we discuss snRNA biosynthesis and the roles of Integrator proteins. We compare models of 3′ end formation for different classes of RNA polymerase II transcripts and formulate/propose a model of Integrator function in snRNA biogenesis.