Department of Molecular Genòmics, Institute of Molecular Biology of Barcelona (IBMB), Barcelona, Spain.
Wiley Interdiscip Rev RNA. 2012 Sep-Oct;3(5):707-17. doi: 10.1002/wrna.1131. Epub 2012 Jul 16.
Most eukaryotic primary transcripts include segments, or introns, that will be accurately removed during RNA biogenesis. This process, known as pre-messenger RNA splicing, is catalyzed by the spliceosome, accurately selecting a set of intronic marks from others apparently equivalent. This identification is critical, as incorrectly spliced RNAs can be toxic for the organism. One of these marks, the dinucleotide AG, signals the intronic 3' end, or 3' splice site (ss). In this review we will focus on those intronic features that have an impact on 3' ss selection. These include the location and type of neighboring sequences, and their distance to the 3' end. We will see that their interplay is needed to select the right intronic end, and that this can be modulated by additional intronic elements that contribute to alternative splicing, whereby diverse RNAs can be generated from identical precursors. This complexity, still poorly understood, is fundamental for the accuracy of gene expression. In addition, a clear knowledge of 3' ss selection is needed to fully decipher the coding potential of genomes.
大多数真核生物的初级转录本包含在 RNA 生物发生过程中会被准确切除的片段，或内含子。这个过程被称为前信使 RNA 剪接，由剪接体催化，从其他看似等效的内含子标记中准确选择一组内含子标记。这种识别是至关重要的，因为错误剪接的 RNA 可能对生物体有毒。这些标记之一是二核苷酸 AG，它标志着内含子的 3' 末端，或 3' 剪接位点 (ss)。在这篇综述中，我们将重点关注那些对 3' ss 选择有影响的内含子特征。这些特征包括邻近序列的位置和类型，以及它们与 3' 末端的距离。我们将看到，它们的相互作用对于选择正确的内含子末端是必要的，并且这种相互作用可以通过有助于可变剪接的其他内含子元件来调节，从而可以从相同的前体生成不同的 RNA。这种复杂性，仍然知之甚少，是基因表达准确性的基础。此外，为了充分破译基因组的编码潜力，还需要清楚地了解 3' ss 选择。
