Birth of New Spliceosomal Introns in Fungi by Multiplication of Introner-like Elements
Birth of New Spliceosomal Introns in Fungi by Multiplication of Introner-like Elements
复制标题
通过内含子样元件的倍增在真菌中产生新的剪接体内含子
DOI：
10.1016/j.cub.2012.05.011
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发表时间：
2012
期刊：
影响因子：
9.2
通讯作者：
J. Collemare
中科院分区：
文献类型：
--
作者：
A. Burgt;E. Severing;P. D. Wit;J. Collemare
剪接体内含子是真核生物基因中分离外显子的非编码序列，通过剪接机制从前信使RNA中去除。自发现以来，它们的起源一直是生物学中的一个谜[1，2]，因为内含子增益似乎在许多真核细胞谱系中并不常见[3，4]。尽管最近有报道称内含子增加了[5，6]，但没有一种提出的增加机制[7]能够令人信服地解释当今真核生物基因组中大量的内含子。在这里，我们报告了特定的剪接体内含子，它们具有高度的序列相似性，并使人想起内含子元件[8]。这些元件在六种真菌基因组的不相关基因中繁殖，并占这些真菌物种中内含子增益的绝大多数。这样的内含子样元件（ILE）包含规则剪接体内含子（RSIs）的所有典型特征[9，10]，但是更长并且预测具有更稳定的二级结构。然而，倍增事件的年代测定表明，它们在10万年内的序列和长度退化，最终变得与RSIs无法区分。我们认为，ILEs不仅占内含子增益在六种真菌，但也在祖先的真核生物，以引起大多数RSIs的一个未知的增殖机制。
Spliceosomal introns are noncoding sequences that separate exons in eukaryotic genes and are removed from pre-messenger RNAs by the splicing machinery. Their origin has remained a mystery in biology since their discovery [1, 2] because intron gains seem to be infrequent in many eukaryotic lineages [3, 4]. Although a few recent intron gains have been reported [5, 6], none of the proposed gain mechanisms [7] can convincingly explain the high number of introns in present-day eukaryotic genomes. Here we report on particular spliceosomal introns that share high sequence similarity and are reminiscent of introner elements [8]. These elements multiplied in unrelated genes of six fungal genomes and account for the vast majority of intron gains in these fungal species. Such introner-like elements (ILEs) contain all typical characteristics of regular spliceosomal introns (RSIs) [9, 10] but are longer and predicted to harbor more stable secondary structures. However, dating of multiplication events showed that they degenerate in sequence and length within 100,000 years to eventually become indistinguishable from RSIs. We suggest that ILEs not only account for intron gains in six fungi but also in ancestral eukaryotes to give rise to most RSIs by a yet unknown multiplication mechanism.
影响因子：
13.8
作者：
Warf, M. Bryan;Berglund, J. Andrew
通讯作者：
Berglund, J. Andrew
影响因子：
7.2
作者：
Mathews, David H.;Moss, Walter N.;Turner, Douglas H.
通讯作者：
Turner, Douglas H.