Self-splicing group I introns in eukaryotic viruses
Self-splicing group I introns in eukaryotic viruses
复制标题
真核病毒中的自剪接 I 组内含子
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
P. Songsri
中科院分区：
文献类型：
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作者：
Takashi Yamada;K. Tamura;T. Aimi;P. Songsri
我们报告的发生自我剪接组I内含子的病毒感染真核绿色小球藻。内含子包含先前针对IB组内含子描述的一级序列和二级结构的所有保守特征。小球藻病毒内含子（约400 nt）在体外自我剪接，产生典型的I组内含子剪接中间体和产物。与真核细胞核I组内含子都位于rRNA基因中不同，这些内含子插入到编码蛋白质的基因中。在一种情况下，外显子编码的蛋白质与真核转录因子SII（TFIIS）具有显著的同源性，这可能对病毒基因表达很重要。在另一种情况下，具有未知功能的14.2 kDa多肽的开放阅读框（ORF）的基因包含内含子。这些内含子的病毒物种之间的分散分布和它们的结构相似的组I内含子的藻类和原生生物表明水平内含子传输。这些真核病毒的内含子提供了一个机会，以了解如何组I内含子到达不同的系统发育王国的生物。
We report the occurrence of self-splicing group I introns in viruses that infect the eukaryotic green alga Chlorella. The introns contained all the conserved features of primary sequence and secondary structure previously described for the group IB introns. The Chlorella viral introns (approximately 400 nt) self-spliced in vitro, yielding the typical group I intron splicing intermediates and products. Contrasting to eukaryotic nuclear group I introns, all of which are located in the rRNA genes, these introns were inserted in genes encoding proteins. In one case, the exons encoded a protein showing significant homology to the eukaryotic transcription factor SII (TFIIS), which may be important for viral gene expression. In another case, the gene for the open reading frame (ORF) of a 14.2 kDa polypeptide with unknown functions contained the intron. Scattered distribution of these introns among the viral species and their structural similarity to the group I introns of algae and protists indicated horizontal intron transmission. These eukaryotic viral introns offer an opportunity to understand how group I introns reach organisms of different phylogenetic kingdoms.