Widespread genome reorganization of an obligate virus mutualist.
Widespread genome reorganization of an obligate virus mutualist.
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专性病毒共同主义的广泛基因组重组。
DOI：
10.1371/journal.pgen.1004660
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发表时间：
2014-09
期刊：
影响因子：
4.5
通讯作者：
Strand MR
中科院分区：
文献类型：
--
作者：
Burke GR;Walden KK;Whitfield JB;Robertson HM;Strand MR
多脱氧核糖核酸病毒科之所以引起人们的兴趣，是因为它提供了与动物宿主进化出互利关系的病毒的最好例子。Bracovirus属中的多DNA病毒与茧蜂科中的寄生蜂严格相关，并且在200亿年前从裸壳进化而来。每种黄蜂依靠其相关的杆状病毒寄生宿主，而每种杆状病毒依靠其黄蜂进行垂直传播。此前的研究证实，臂病毒基因组由前病毒片段和裸病毒样复制基因组成，但这些成分在黄蜂基因组中的组织方式尚不清楚。在这里，我们测序的基因组的黄蜂侧沟茧蜂demolitor的特点，前病毒基因组M。强心剂杆状病毒（MdBV）。与裸病毒不同，杆状病毒产生包装多个环状双链DNA的病毒体。包装成MdBV病毒粒子的DNA片段位于M.破坏者基因组每个前病毒片段由同源基序限制，所述同源基序引导加工以形成成熟的病毒DNA。前病毒片段的快速进化掩盖了其他携带杆状病毒的黄蜂和MdBV之间的同源性。然而，MdBV前病毒基因座侧翼的一些结构域与其他物种共享。鉴定了先前鉴定为编码复制所需蛋白质的所有MdBV基因。其中一些基因位于多基因簇中，但其他基因，包括转录结构基因的RNA聚合酶亚基和加工前病毒片段的整合酶，广泛分布在M.破坏者基因组总的来说，我们的研究结果表明，基因组分散是一个关键特征，在进化的bracoviruses到互利。微生物与多细胞生物形成了从拮抗（寄生）到有益（互利）的专性联系。虽然存在许多专性互利细菌、真菌和原生动物的例子，但病毒通常被认为是寄生性的。一个例外是Polydnaviridae家族，它由大型DNA病毒组成，这些病毒已经进化成被称为寄生蜂的昆虫的互利主义者。每种黄蜂依靠其相关的多DNA病毒寄生宿主，而每种多DNA病毒依靠其黄蜂进行传播。大约1亿年前，Bracovirus属的多DNA病毒从一组称为裸病毒的病毒进化而来，裸病毒与另一个称为杆状病毒的病毒大家族密切相关，杆状病毒是昆虫的致命病原体。因此，臂状病毒很有意义，因为它们提供了一个研究系统，用于研究进化成互利主义者如何影响病毒基因组的结构和功能。在这项研究中，我们对蜜蜂侧沟茧蜂的基因组进行了测序，以表征M。强心剂杆状病毒（MdBV）。杆状病毒的病毒祖先具有独立的环状基因组，而MdBV的前病毒基因组广泛分布在M.爆破工我们的研究结果还为MdBV基因组如何产生黄蜂赖以寄生宿主昆虫的病毒颗粒提供了新的见解。
The family Polydnaviridae is of interest because it provides the best example of viruses that have evolved a mutualistic association with their animal hosts. Polydnaviruses in the genus Bracovirus are strictly associated with parasitoid wasps in the family Braconidae, and evolved ∼100 million years ago from a nudivirus. Each wasp species relies on its associated bracovirus to parasitize hosts, while each bracovirus relies on its wasp for vertical transmission. Prior studies establish that bracovirus genomes consist of proviral segments and nudivirus-like replication genes, but how these components are organized in the genomes of wasps is unknown. Here, we sequenced the genome of the wasp Microplitis demolitor to characterize the proviral genome of M. demolitor bracovirus (MdBV). Unlike nudiviruses, bracoviruses produce virions that package multiple circular, double-stranded DNAs. DNA segments packaged into MdBV virions resided in eight dispersed loci in the M. demolitor genome. Each proviral segment was bounded by homologous motifs that guide processing to form mature viral DNAs. Rapid evolution of proviral segments obscured homology between other bracovirus-carrying wasps and MdBV. However, some domains flanking MdBV proviral loci were shared with other species. All MdBV genes previously identified to encode proteins required for replication were identified. Some of these genes resided in a multigene cluster but others, including subunits of the RNA polymerase that transcribes structural genes and integrases that process proviral segments, were widely dispersed in the M. demolitor genome. Overall, our results indicate that genome dispersal is a key feature in the evolution of bracoviruses into mutualists. Microorganisms form obligate associations with multicellular organisms that range from antagonistic (parasitic) to beneficial (mutualists). Although numerous examples of obligate, mutualistic bacteria, fungi, and protozoans exist, viruses are thought to usually form parasitic associations. An exception is the family Polydnaviridae, which consists of large DNA viruses that have evolved into mutualists of insects called parasitoid wasps. Each wasp species relies on its associated polydnavirus to parasitize hosts while each polydnavirus relies on its wasp for transmission. Polydnaviruses in the genus Bracovirus evolved approximately 100 million years ago from a group of viruses called nudiviruses, which are closely related to another large family of viruses called baculoviruses that are virulent pathogens of insects. Bracoviruses are of interest, therefore, because they provide a study system for examining how evolution into mutualists affects the structure and function of viral genomes. In this study, we sequenced the genome of the wasp Microplitis demolitor to characterize the proviral genome of M. demolitor bracovirus (MdBV). While the viral ancestor of bracoviruses possessed an independent circular genome, the proviral genome of MdBV is widely dispersed in the genome of M. demolitor. Our results also provide new insights into how the MdBV genome functions to produce virus particles that wasps rely upon to parasitize host insects.
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影响因子：
12.3
作者：
Desjardins, Christopher A.;Gundersen-Rindal, Dawn E.;Hostetler, Jessica B.;Tallon, Luke J.;Fadrosh, Douglas W.;Fuester, Roger W.;Pedroni, Monica J.;Haas, Brian J.;Schatz, Michael C.;Jones, Kristine M.;Crabtree, Jonathan;Forberger, Heather;Nene, Vishvanath
通讯作者：
Nene, Vishvanath
影响因子：
6.7
作者：
Burke GR;Thomas SA;Eum JH;Strand MR
通讯作者：
Strand MR
影响因子：
5.4
作者：
Chen, Yun-Ru;Zhong, Silin;Blissard, Gary W.
通讯作者：
Blissard, Gary W.
影响因子：
3.8
作者：
Bitra, Kavita;Zhang, Shu;Strand, Michael R.
通讯作者：
Strand, Michael R.
影响因子：
5.4
作者：
Burke, Gaelen R.;Strand, Michael R.
通讯作者：
Strand, Michael R.