Abstract：
A recent marine metagenomic study has revealed the existence of a novel group of viruses designated mirusviruses, which are proposed to form an evolutionary link between two realms of double-stranded DNA viruses, Varidnaviria and Duplodnaviria. Metagenomic data suggest that mirusviruses infect microeukaryotes in the photic layer of the ocean, but their host range remains largely unknown. In this study, we investigated the presence of mirusvirus marker genes in 1,901 publicly available eukaryotic genome assemblies, mainly derived from unicellular eukaryotes, to identify potential hosts of mirusviruses. Mirusvirus marker sequences were identified in 915 assemblies spanning 227 genera across eight supergroups of eukaryotes. The habitats of the putative mirusvirus hosts included not only marine but also other diverse environments. Among the major capsid protein (MCP) signals in the genome assemblies, we identified 85 sequences that showed high sequence and structural similarities to reference mirusvirus MCPs. A phylogenetic analysis of these sequences revealed their distant evolutionary relationships with the seven previously reported mirusvirus clades. Most of the scaffolds with these MCP sequences encoded multiple mirusvirus homologs, suggesting that mirusviral infection contributes to the alteration of the host genome. We also identified three circular mirusviral genomes within the genomic data of the oil-producing thraustochytrid Schizochytrium sp. and the endolithic green alga Ostreobium quekettii. Overall, mirusviruses probably infect a wide spectrum of eukaryotes and are more diverse than previously reported.
摘要：
最近的一项海洋宏基因组研究揭示了一组新的病毒的存在，被称为Mirusvirus病毒，它们被提议在双链DNA病毒的两个领域之间形成进化联系，Varidnavria和Duplodnavria。宏基因组数据表明，mirusvirus感染海洋光层中的微真核生物，但是它们的宿主范围仍然未知。在这项研究中,我们调查了1,901个公开的真核细胞基因组组件中的mirusvirus标记基因的存在，主要来自单细胞真核生物，来识别潜在的mirusvirus宿主.Mirusvirus标记序列在8个真核生物超群中跨越227个属的915个装配体中鉴定。假定的mirusvirus宿主的栖息地不仅包括海洋环境，还包括其他不同的环境。在基因组组装中的主要衣壳蛋白（MCP）信号中，我们鉴定出85个与参比mirusvirusMCP具有高度序列和结构相似性的序列.对这些序列的系统发育分析揭示了它们与先前报道的七个mirusvirus进化枝的遥远进化关系。大多数具有这些MCP序列的支架编码多个毛象病毒同源物，提示毛病毒感染有助于宿主基因组的改变。我们还在产油的破囊氏囊裂殖囊虫的基因组数据中确定了三个环形病毒基因组。和石器时代的绿色藻类Ostreobiumquecktii。总的来说,mirusvirus可能感染广泛的真核生物，并且比以前报道的更加多样化。
