Mechanistic insights into human pre-mRNA splicing of human ultra-short introns: Potential unusual mechanism identifies G-rich introns
Mechanistic insights into human pre-mRNA splicing of human ultra-short introns: Potential unusual mechanism identifies G-rich introns
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DOI：
10.1016/j.bbrc.2012.05.112
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发表时间：
2012-06-29
影响因子：
3.1
通讯作者：
Mayeda, Akila
中科院分区：
文献类型：
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作者：
Sasaki-Haraguchi, Noriko;Shimada, Makoto K.;Mayeda, Akila
目前还不清楚如何非常短的内含子（2.7 MDa）没有空间位阻。通过筛选注释的人类转录组数据库（H-InvDB），我们确定了三个模型超短内含子：HNRNPH 1（hnRNP H1）基因中的56-nt内含子、NDOR 1（NADPH依赖性二黄素氧化还原酶1）基因中的49-nt内含子和ESRP 2（上皮剪接调节蛋白2）基因中的43-nt内含子。我们验证了这些内源性超短内含子是剪接的，并且在用相应的小基因转染的培养细胞中也重演了这一点。这些超短内含子的剪接被剪接抑制剂spliceostatin A抑制，表明SF 3b（U2 snRNP组分）参与了它们的剪接过程。56-nt的内含子含有嘧啶丰富的道被剪接出的lymphocyte形式，这种剪接被抑制的破坏U1，U2，或U4的snRNA。相比之下，49-和43-nt的内含子是富含嘌呤的整体没有任何嘧啶丰富的道，这些lcRNA是不可检测的。值得注意的是，在49-和43-nt内含子中共享的富含G的内含子序列是其剪接所必需的，这表明这些超短内含子可能募集与富含G的内含子剪接增强子相关的新的辅助剪接机制。(C)2012 Elsevier Inc. All rights reserved.
It is unknown how very short introns (2.7 MDa) without steric hindrance. By screening an annotated human transcriptome database (H-InvDB), we identified three model ultra-short introns: the 56-nt intron in the HNRNPH1 (hnRNP H1) gene, the 49-nt intron in the NDOR1 (NADPH dependent diflavin oxidoreductase 1) gene, and the 43-nt intron in the ESRP2 (epithelial splicing regulatory protein 2) gene. We verified that these endogenous ultra-short introns are spliced, and also recapitulated this in cultured cells transfected with the corresponding mini-genes. The splicing of these ultra-short introns was repressed by a splicing inhibitor, spliceostatin A, suggesting that SF3b (a U2 snRNP component) is involved in their splicing processes. The 56-nt intron containing a pyrimidine-rich tract was spliced out in a lariat form, and this splicing was inhibited by the disruption of U1, U2, or U4 snRNA. In contrast, the 49- and 43-nt introns were purine-rich overall without any pyrimidine-rich tract, and these lariat RNAs were not detectable. Remarkably, shared G-rich intronic sequences in the 49- and 43-nt introns were required for their splicing, suggesting that these ultra-short introns may recruit a novel auxiliary splicing mechanism linked to G-rich intronic splicing enhancers. (C) 2012 Elsevier Inc. All rights reserved.