Requirements for intron-mediated enhancement of gene expression in Arabidopsis
Requirements for intron-mediated enhancement of gene expression in Arabidopsis
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DOI：
10.1017/s1355838202020551
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发表时间：
2002-11-01
期刊：
影响因子：
4.5
通讯作者：
Rose, AB
中科院分区：
文献类型：
--
作者：
Rose, AB
为了探索内含子介导的基因表达增强的可能机制，在转基因拟南芥中系统地测试了PAT 1内含子1提高mRNA积累所需的特征。该内含子具有显著的弹性，当5'和3'剪接位点、分支点序列的突变阻止剪接时，或当内含子U丰富度降低时，保留了增加mRNA积累的一些能力。通过同时消除分支点和5'剪接位点来消除增强，这些结构参与剪接体组装的前两个步骤。虽然这表明剪接机制是必需的，但内含子剪接显然不足以增强mRNA的积累。其他五个内含子都被有效地剪接，但在增加mRNA水平的能力上差异很大。此外，PAT1内含子1被剪接，但当移动到3'UTR时失去了提高mRINA积累的能力。这些发现表明，剪接本身对于内含子增强mRINA积累来说既不是必要的，也不是充分的，并提出了一种需要剪接机制识别内含子但也涉及非保守内含子序列的机制。
To explore possible mechanisms of intron-mediated enhancement of gene expression, the features of PAT1 intron 1 required to elevate mRNA accumulation were systematically tested in transgenic Arabidopsis. This intron is remarkably resilient, retaining some ability to increase mRNA accumulation when splicing was prevented by mutation of 5' and 3' splice sites, branchpoint sequences, or when intron U-richness was reduced. Enhancement was abolished by simultaneously eliminating branchpoints and the 5' splice site, structures involved in the first two steps of spliceosome assembly. Although this suggests that the splicing machinery is required, intron splicing is clearly not enough to enhance mRNA accumulation. Five other introns were all efficiently spliced but varied widely in their ability to increase mRNA levels. Furthermore, PAT1 intron 1 was spliced but lost the ability to elevate mRINA accumulation when moved to the 3' UTR. These findings demonstrate that splicing per se is neither necessary nor sufficient for an intron to enhance mRINA accumulation, and suggest a mechanism that requires intron recognition by the splicing machinery but also involves nonconserved intron sequences.