Giant virus with a remarkable complement of genes infects marine zooplankton
Giant virus with a remarkable complement of genes infects marine zooplankton
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DOI：
10.1073/pnas.1007615107
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发表时间：
2010-11-09
影响因子：
11.1
通讯作者：
Suttle, Curtis A.
中科院分区：
文献类型：
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作者：
Fischer, Matthias G.;Allen, Michael J.;Suttle, Curtis A.
作为异养细菌和浮游植物的主要消费者，微型浮游动物是水生食物网中至关重要的一环。在这里，我们展示了一个主要的海洋微鞭毛虫食草动物感染了一种巨大的病毒，咖啡馆罗伯根病毒(CroV)，它拥有所有已描述的海洋病毒中最大的基因组(约730kb的双链DNA)。这个富含AT的基因组中央618kb的编码部分包含544个预测的蛋白质编码基因；已经检测到可能的早期启动子和晚期启动子基序，分别分配给其中的191个和72个，至少274个基因在感染过程中表达。CroV的不同编码能力包括预测的翻译因子、DNA修复酶如DNA错配修复蛋白MutS和两个光解酶、多种泛素途径组件、四个内含子元件和22个tRNAs。许多基因，包括异亮氨酰-tRNA合成酶、eIF-2-γ和Elp3样组蛋白乙酰转移酶，在病毒中通常是不存在的。我们还发现了一个38kb的推测细菌起源的基因组区域，该区域编码几种预测的碳水化合物代谢酶，包括3-脱氧-D-甘露糖的整个生物合成途径，3-脱氧-D-甘露糖是革兰氏阴性细菌外膜的关键成分。系统进化分析表明，CroV是一种核质大DNA病毒，与棘阿米巴多噬拟病毒是其最近的亲缘关系，但只有不到三分之一的CroV基因与Mimi病毒有同源性。CroV是一种高度复杂的海洋病毒，也是唯一一种对基因细节进行研究的病毒，它可以感染海洋中的一种主要捕食者群体。
As major consumers of heterotrophic bacteria and phytoplankton, microzooplankton are a critical link in aquatic foodwebs. Here, we show that a major marine microflagellate grazer is infected by a giant virus, Cafeteria roenbergensis virus (CroV), which has the largest genome of any described marine virus (approximate to 730 kb of double-stranded DNA). The central 618-kb coding part of this AT-rich genome contains 544 predicted protein-coding genes; putative early and late promoter motifs have been detected and assigned to 191 and 72 of them, respectively, and at least 274 genes were expressed during infection. The diverse coding potential of CroV includes predicted translation factors, DNA repair enzymes such as DNA mismatch repair protein MutS and two photolyases, multiple ubiquitin pathway components, four intein elements, and 22 tRNAs. Many genes including isoleucyl-tRNA synthetase, eIF-2 gamma, and an Elp3-like histone acetyltransferase are usually not found in viruses. We also discovered a 38-kb genomic region of putative bacterial origin, which encodes several predicted carbohydrate metabolizing enzymes, including an entire pathway for the biosynthesis of 3-deoxy-D-manno-octulosonate, a key component of the outer membrane in Gram-negative bacteria. Phylogenetic analysis indicates that CroV is a nucleocytoplasmic large DNA virus, with Acanthamoeba polyphaga mimivirus as its closest relative, although less than one-third of the genes of CroV have homologs in Mimivirus. CroV is a highly complex marine virus and the only virus studied in genetic detail that infects one of the major groups of predators in the oceans.