Mitochondrial Group II Introns in the Raphidophycean Flagellate Chattonella spp. Suggest a Diatom-to-Chattonella Lateral Group II Intron Transfer
Mitochondrial Group II Introns in the Raphidophycean Flagellate Chattonella spp. Suggest a Diatom-to-Chattonella Lateral Group II Intron Transfer
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DOI：
10.1016/j.protis.2009.02.003
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发表时间：
2009-08-01
期刊：
影响因子：
2.5
通讯作者：
Sako, Yoshihiko
中科院分区：
文献类型：
--
作者：
Kamikawa, Ryoma;Masuda, Isao;Sako, Yoshihiko
在四种raphiophyic鞭毛虫Chattonella antiqua， c . marina, c . ovata和c . minima的细胞色素c氧化酶亚基I （cox1）基因中，我们发现了两个II组内含子，这里称为Chattonella cox1-i1和Chattonella cox1-i2，编码一个开放阅读框架（ORF），该框架由三个结构域组成：逆转录酶（RT）， RNA成熟酶（Ma）和锌指（H-N-H）内切酶结构域。二级结构表明，Chattonella cox1-i1和Chattonella cox1-i2都属于IIA1类群，尽管前者在臂i的ε '区具有类似IIB类群的二级结构特征。内含子的二级结构表明，查顿菌cox1-i1可能与5种系统发育分化的真核生物cox1基因中插入的II族内含子具有共同的进化起源。相比之下，Chattonella cox1-i2被认为与硅藻cox1基因中的II族内含子具有密切的进化亲和力。基于RT结构域的系统发育显示了一个树形拓扑结构，其中查顿菌cox1-i2嵌套在硅藻序列中，表明硅藻到查顿菌的内含子转移已经发生。最后，我们在深分枝raphiophysians的cox1基因中没有发现内含子。根据简略的讨论，查顿菌cox1-i1和查顿菌cox1-i2从盐下查顿菌（C. subsalsa）分化后侵入了查顿菌祖先细胞的cox1基因。2009爱思唯尔有限公司版权所有。
In the cytochrome c oxidase subunit I (cox1) gene of four raphidophycean flagellates Chattonella antiqua, C. marina, C. ovata, and C. minima we found two group II introns described here as Chattonella cox1-i1 and Chattonella cox1-i2 encoding an open reading frame (ORF) comprised of three domains: reverse transcriptase (RT), RNA maturase (Ma) and zinc finger (H-N-H) endonuclease domains. The secondary structures show both Chattonella cox1-i1 and Chattonella cox1-i2 belong to group IIA1, albeit the former possesses a group IIB- like secondary structural character in the epsilon' region of arm I. Our phylogenetic analysis inferred from RT domain sequences of the intronic ORF, comparison of the insertionsites, and the secondary structures of the introns suggests that Chattonella cox1-i1 likely shares an evolutionary origin with the group II introns inserted in cox1 genes of five phylogenetically diverged eukaryotes. In contrast, Chattonella cox1-i2 was suggested to bear a close evolutionary affinity to the group II introns found in diatom cox 1 genes. The RT domain-based phylogeny shows a tree topology in which Chattonella cox1-i2 is nested in the diatom sequences suggesting that a diatom-to-Chattonella intron transfer has taken place. Finally, we found no intron in cox1 genes from deeper-branching raphidophyceans. Based on parsimonious discussion, Chattonella cox1-i1 and Chattonellacox1-i2 have invaded into the cox1 gene of an ancestral Chattonella cellafter diverging from C. subsalsa. (C) 2009 Elsevier GmbH. All rights reserved.