纤毛虫原生动物的分子生物学研究:若干热点领域及新进展  

On molecular biology of ciliated protozoa:Frontier areas and progresses

作　　者：伊珍珍[1] 苗苗[2] 高珊[3] 高凤[3] 宋微波[3] 

机构地区：[1]华南师范大学广州亚热带生物多样性与环境生物监测重点实验室,广州510631 [2]中国科学院大学存济医学院,北京100049 [3]中国海洋大学海洋生物多样性与进化研究所,青岛266003

出　　处：《科学通报》2016年第20期2227-2238,共12页Chinese Science Bulletin

基　　金：青岛市应用基础研究计划(15-12-1-1-jch);国家自然科学基金(31471973)资助

摘　　要：作为分子生物学研究的重要模式材料,纤毛门原生动物在细胞生物学、遗传学、基因组学、生态学以及真核生物的起源和进化等领域均具有重要的研究价值.近年来,本团队在纤毛虫多样性和细胞学研究的同时,聚焦在纤毛虫的分子生物学领域并形成了一批新成果:完成了多个代表性类群2000余条标记性基因的测序和提交以及基因标记筛选、拓扑结构优化等相关的方法学探讨;以此为基础,开展了门内50余个纲目级阶元系统关系的梳理以及基于多基因分析对整个纤毛门的系统树重构建;揭示了四膜虫(Tetrahymena)的一个重要表观遗传学新现象,即特异性修饰组蛋白H3第27位赖氨酸的单甲基化酶TXR1的敲除将严重影响DNA复制延伸的速度和保守度,证实了表观遗传信息的微扰可直接影响遗传信息的复制;对具沟急游虫(Strombidium sulcatum)等6个代表种的转录组/全基因组/线粒体基因组的测序和分析,为纤毛虫进化过程中关键节点种类定位、寻找功能基因家族与形态特征的相关性提供了大量信息;首次发现了选择性拼接在钩刺斜管虫(Chilodonella uncinata)的基因家族中广泛存在并提出一新的理论模型:选择性拼接可能是基因乱序进化过程的中间形式,为探讨纤毛虫物种分化、形成机制提供了一新的视角;在对DNA条形码候选基因分析比较的基础上,初步揭示出不同纤毛虫类群生境间的迁移机制,发现和定位了4个优良候选区段并构建了80余种代表性类群的基因条形码数据库.Ciliated protists are important organisms which play significant roles in studies on cell biology, genetics, biodiversity, biogeography and ecology, environmental biology etc. In last decade, molecular investigations on phylogeny, barcoding, epigenetics, genomics, and gene evolution have been performed by the authors＇ groups and the main results can be summarized as follows：（i） Phylogenetic relationships within over 50 classes/orders are analyzed, and two new classes, six new orders/suborders are established by the authors＇ groups, based on more than 2000 new sequences. Additionally, theoretical researches focusing on gene marker selection and topological optimization are also performed, in order to provide theoretical guidance for future study. We suggested that unidentified environmental sequences, and secondary structures of r RNA gene could be used for inferring phylogenetic relationships of ciliates, at least on some taxon level. And we also discussed the impact of missing data present in concatenated analyses, and paralogs of protein-coding genes on phylogenetic analyses.（ii） Transcriptome/genome genome of six representative ciliates（Strombidium sulcatum, Uronema marinum, Metanophrys similis, Euplotes vannus, Uroleptopsis citrina, Paramecium caudatum） were sequenced and analyzed, which will help to find out the evolutionary position of key species, the relationship between expression of the functional gene family and morphological characteristics, and to understand the association between genetic information and phenotype; Also, we compared mitochondrial genome of the genus Euplotes species, thus found the gene order and transcriptional directions were the same among three species, but 3 split protein coding genes（nad9, nad2 and rpl16） were predicted only in mt-genome of E. vannus.（iii） Knockout of histone methyltransferase TXR1（Tetrahymena Trithorax related 1）, specific for H3 lysine 27 mono-methylation（H3K27me1）, leads to severe replication stress in the model organism Te

关 键 词：纤毛门原生动物 分子系统学 基因条形码 表观遗传学 基因组学 进化 

分 类 号：Q953[生物学—动物学]