Widespread endogenization of giant viruses shapes genomes of green algae
Widespread endogenization of giant viruses shapes genomes of green algae
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DOI：
10.1038/s41586-020-2924-2
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发表时间：
2020-11-18
期刊：
影响因子：
64.8
通讯作者：
Aylward, Frank O.
中科院分区：
文献类型：
--
作者：
Moniruzzaman, Mohammad;Weinheimer, Alaina R.;Aylward, Frank O.
作者指出，来自巨型病毒的大型内源性病毒元件是绿藻基因组的重要组成部分。内源性病毒元件(EVES)--将其基因组整合到宿主基因组中的病毒--在真核生物中普遍存在，在基因组进化中具有重要作用(1，2)。到目前为止，已发现的绝大多数EVE是由几个基因组成的小基因组区域(2)，但最近的证据表明，一些大的双链DNA病毒也可能内源性进入宿主的基因组(1)。核质大DNA病毒(NCLDV)由于其庞大的基因组和复杂的进化起源(3-6)，近年来引起了人们的极大兴趣，但目前尚不清楚它们是否是真核生物EVES的重要组成部分。在这里，我们报道了NCLDV在不同的绿藻中的广泛内源性；这些巨型伊夫类的大小超过100万个碱基对，在一些基因组中包含多达10%的总开放阅读框，大大增加了真核基因组中已知的病毒基因的规模。这些内源元件通常与寄主基因组共享基因，并含有大量剪接体内含子和大量重复，表明它们与寄主基因组紧密同化。NCLDV含有大的马赛克基因组，其基因来自多种来源，它们的内源性作用代表着一种被低估的新遗传物质进入真核血统的管道，这可能会对基因组组成产生重大影响。
The authors show that large endogenous viral elements derived from giant viruses are prominent components of green algal genomes.Endogenous viral elements (EVEs)-viruses that have integrated their genomes into those of their hosts-are prevalent in eukaryotes and have an important role in genome evolution(1,2). The vast majority of EVEs that have been identified to date are small genomic regions comprising a few genes(2), but recent evidence suggests that some large double-stranded DNA viruses may also endogenize into the genome of the host(1). Nucleocytoplasmic large DNA viruses (NCLDVs) have recently become of great interest owing to their large genomes and complex evolutionary origins(3-6), but it is not yet known whether they are a prominent component of eukaryotic EVEs. Here we report the widespread endogenization of NCLDVs in diverse green algae; these giant EVEs reached sizes greater than 1 million base pairs and contained as many as around 10% of the total open reading frames in some genomes, substantially increasing the scale of known viral genes in eukaryotic genomes. These endogenized elements often shared genes with host genomic loci and contained numerous spliceosomal introns and large duplications, suggesting tight assimilation into host genomes. NCLDVs contain large and mosaic genomes with genes derived from multiple sources, and their endogenization represents an underappreciated conduit of new genetic material into eukaryotic lineages that can substantially impact genome composition.