Split Introns in the Genome of Giardia intestinalis Are Excised by Spliceosome-Mediated trans-Splicing
Split Introns in the Genome of Giardia intestinalis Are Excised by Spliceosome-Mediated trans-Splicing
复制标题
通过剪接体介导的反式剪接切除肠贾第鞭毛虫基因组中的分裂内含子
DOI：
10.1016/j.cub.2011.01.025
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发表时间：
2011-02-22
期刊：
影响因子：
9.2
通讯作者：
Hashimoto, Tetsuo
中科院分区：
文献类型：
--
作者：
Kamikawa, Ryoma;Inagaki, Yuji;Hashimoto, Tetsuo
剪接体内含子是大多数真核生物基因组的标志，由细胞中最大、最复杂的分子机器剪接体从早期mrna中切除。贾第鞭毛虫是贾第鞭毛虫病的病原体，是一种分化的单细胞真核生物，它也具有剪接体，但迄今为止在其基因组中仅鉴定出四个典型（顺式剪接）内含子[2-4]。我们证明，这种生物体具有剪接体介导的分裂内含子反式剪接的新形式，这对于至少两个重要基因产生成熟mrna至关重要：一个编码热休克蛋白90 (HSP90)，控制一组细胞蛋白[5]的构象，另一个编码动力蛋白分子运动蛋白，参与真核鞭毛[6]的运动。这些外溢内含子具有与真核生物中已知的其他反式剪接系统不同的特性，这表明贾第鞭毛虫独立地进化出了一种独特的剪接分裂内含子的系统。
Spliceosomal introns are hallmarks of most eukaryotic genomes and are excised from premature mRNAs by a spliceosome that is among the largest, and most complex, molecular machine in cells [1]. The divergent unicellular eukaryote Giardia intestinalis, the causative agent of giardiasis, also possesses spliceosomes, but only four canonical (cis-spliced) introns have been identified in its genome to date [2-4]. We demonstrate that this organism has a novel form of spliceosome-mediated trans-splicing of split introns that is essential for generating mature mRNAs for at least Iwo important genes: one encoding a heat shock protein 90 (HSP90), which controls the conformation of a suite of cellular proteins [5], and the other encoding a dynein molecular motor protein, involved in the motility of eukaryotic flagella [6]. These spill introns have properties that distinguish them from other trans-splicing systems known within eukaryotes, suggesting that Giardia independently evolved a unique system to splice split introns.