Intron-loss evolution of hatching enzyme genes in Teleostei.
Intron-loss evolution of hatching enzyme genes in Teleostei.
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DOI：
10.1186/1471-2148-10-260
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发表时间：
2010-08-27
影响因子：
3.4
通讯作者：
Yasumasu S
中科院分区：
文献类型：
--
作者：
Kawaguchi M;Hiroi J;Miya M;Nishida M;Iuchi I;Yasumasu S
孵化酶是一种在胚胎孵化时破坏卵被膜的蛋白酶，属于虾青素金属蛋白酶家族。在所有脊椎动物的基因组中都发现了这种酶的直链基因。最近，我们发现四足动物的基因外显子-内含子结构是保守的，而硬骨鱼的基因经常丢失内含子。真骨鱼类孵化酶基因中这种内含子丢失的发生是一种罕见的进化事件，因为大多数真核基因通常被内含子中断，并且内含子插入位点在物种之间是保守的。在这里，我们报告了广泛的研究的外显子-内含子结构的硬骨鱼孵化酶基因的深入了解如何以及为什么内含子在进化过程中丢失。我们研究了27种真骨鱼类孵化酶基因内含子丢失的进化途径。底栖硬骨鱼的孵化酶基因只有一种类型，它保留了假定祖先的9-外显子-8-内含子结构。另一方面，耳首类和真硬骨鱼类具有两种类型的孵化酶基因，这表明在耳首类和真硬骨鱼类的共同祖先中发生了基因复制事件。系统发育分析结果表明，重复基因可分为两个分支，即分支I和分支II。在耳首鱼类和真硬骨鱼类中，进化枝I基因形成了一种遗传特异性结构，如8-外显子-7-内含子、5-外显子-4-内含子、4-外显子-3-内含子或无内含子结构。与进化枝I基因相比，进化枝II基因的结构相对稳定，与祖先基因的结构相似。表达分析表明，孵化酶基因是高表达的基因相比，管家基因。当在进化枝I和II基因之间比较表达水平时，进化枝I基因倾向于比进化枝II基因表达更高。孵化酶基因的进化失去了它们的内含子，而内含子丢失事件发生在硬骨鱼发育的特定点。我们认为，在硬骨鱼进化过程中，高表达的孵化酶基因经常丢失其内含子，而低表达的基因保持祖先基因的外显子-内含子结构。
Hatching enzyme, belonging to the astacin metallo-protease family, digests egg envelope at embryo hatching. Orthologous genes of the enzyme are found in all vertebrate genomes. Recently, we found that exon-intron structures of the genes were conserved among tetrapods, while the genes of teleosts frequently lost their introns. Occurrence of such intron losses in teleostean hatching enzyme genes is an uncommon evolutionary event, as most eukaryotic genes are generally known to be interrupted by introns and the intron insertion sites are conserved from species to species. Here, we report on extensive studies of the exon-intron structures of teleostean hatching enzyme genes for insight into how and why introns were lost during evolution. We investigated the evolutionary pathway of intron-losses in hatching enzyme genes of 27 species of Teleostei. Hatching enzyme genes of basal teleosts are of only one type, which conserves the 9-exon-8-intron structure of an assumed ancestor. On the other hand, otocephalans and euteleosts possess two types of hatching enzyme genes, suggesting a gene duplication event in the common ancestor of otocephalans and euteleosts. The duplicated genes were classified into two clades, clades I and II, based on phylogenetic analysis. In otocephalans and euteleosts, clade I genes developed a phylogeny-specific structure, such as an 8-exon-7-intron, 5-exon-4-intron, 4-exon-3-intron or intron-less structure. In contrast to the clade I genes, the structures of clade II genes were relatively stable in their configuration, and were similar to that of the ancestral genes. Expression analyses revealed that hatching enzyme genes were high-expression genes, when compared to that of housekeeping genes. When expression levels were compared between clade I and II genes, clade I genes tends to be expressed more highly than clade II genes. Hatching enzyme genes evolved to lose their introns, and the intron-loss events occurred at the specific points of teleostean phylogeny. We propose that the high-expression hatching enzyme genes frequently lost their introns during the evolution of teleosts, while the low-expression genes maintained the exon-intron structure of the ancestral gene.
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影响因子：
64.5
作者：
CHOW, LT;GELINAS, RE;ROBERTS, RJ
通讯作者：
ROBERTS, RJ
影响因子：
11.4
作者：
Jeffares, Daniel C.;Penkett, Christopher J.;Baehler, Juerg
通讯作者：
Baehler, Juerg
影响因子：
10.7
作者：
Loh, Yong-Hwee;Brenner, Sydney;Venkatesh, Byrappa
通讯作者：
Venkatesh, Byrappa
影响因子：
14.9
作者：
Irimia M;Roy SW
通讯作者：
Roy SW
DOI：
10.1073/pnas.0500383102
发表时间：
2005-04-19
影响因子：
11.1
作者：
Roy, SW;Gilbert, W
通讯作者：
Gilbert, W