The Genome of the Foraminiferan Reticulomyxa filosa
The Genome of the Foraminiferan Reticulomyxa filosa
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DOI：
10.1016/j.cub.2013.11.027
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发表时间：
2014-01-06
期刊：
影响因子：
9.2
通讯作者：
Schliwa, Manfred
中科院分区：
文献类型：
--
作者：
Gloeckner, Gernot;Huelsmann, Norbert;Schliwa, Manfred
背景：根茎是真核生物进化的一个主要分支，有广泛的微化石记录，但只有很少的分子数据可用。丝状网孔虫属有孔虫目，是一种在淡水环境中自由生活的根瘤菌。在培养中，它只能在一个细胞中以具有数千个单倍体核的疟原虫的形式繁殖。丝状孔虫基因组是第一个被破译的有孔虫基因组。结果：基因组具有极强的重复性，大量的相同序列暗示着频繁的扩增和同源重组事件。据推测，这些机制被用来为更高的转录活性提供更多的基因拷贝，并在某些基因家族（如激酶家族）中建立基因多样化的储存库。基因库表明，它能够切换到单细胞，鞭毛性状态从未在培养中观察到。与另一种根瘤菌，绿蛛纲藻类Bigelowiella natans的比较表明，参与信号传导的蛋白质可能是建立根瘤菌谱系的驱动因素。与其他原生生物相比，水平基因转移是有限的，但我们发现了细菌到真核生物和真核生物到真核生物转移事件的证据。结论：黄毛霉基因组具有独特的结构，具有广泛的重复均质化和基因扩增，这表明其具有不同生命周期阶段的潜力。r . filosa快速运输物质的能力从伪足胞体可能是由肌动蛋白的高分散和驱动蛋白基因家族成员。
Background: Rhizaria are a major branch of eukaryote evolution with an extensive microfossil record, but only scarce molecular data are available. The rhizarian species Reticulomyxa filosa, belonging to the Foraminifera, is free-living in freshwater environments. In culture, it thrives only as a plasmodium with thousands of haploid nuclei in one cell. The R. filosa genome is the first foraminiferal genome to be deciphered.Results: The genome is extremely repetitive, and the large amounts of identical sequences hint at frequent amplifications and homologous recombination events. Presumably, these mechanisms are employed to provide more gene copies for higher transcriptional activity and to build up a reservoir of gene diversification in certain gene families, such as the kinesin family. The gene repertoire indicates that it is able to switch to a single-celled, flagellated sexual state never observed in culture. Comparison to another rhizarian, the chlorarachniophyte alga Bigelowiella natans, reveals that proteins involved in signaling were likely drivers in establishing the Rhizaria lineage. Compared to some other protists, horizontal gene transfer is limited, but we found evidence of bacterial-to-eukaryote and eukaryote-to-eukaryote transfer events.Conclusions: The R. filosa genome exhibits a unique architecture with extensive repeat homogenization and gene amplification, which highlights its potential for diverse life-cycle stages. The ability of R. filosa to rapidly transport matter from the pseudopodia to the cell body may be supported by the high diversification of actin and kinesin gene family members.