Functional endogenous viral elements in the genome of the parasitoid wasp Cotesia congregata: insights into the evolutionary dynamics of bracoviruses
Functional endogenous viral elements in the genome of the parasitoid wasp Cotesia congregata: insights into the evolutionary dynamics of bracoviruses
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DOI：
10.1098/rstb.2013.0047
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发表时间：
2013-09-19
影响因子：
6.3
通讯作者：
Drezen, Jean-Michel
中科院分区：
文献类型：
--
作者：
Bezier, Annie;Louis, Faustine;Drezen, Jean-Michel
臂状病毒是迄今为止所描述的最复杂的内源性病毒元件。自大约100年前以来，裸芽病毒基因已被寄主在拟寄生蜂基因组中。它们在黄蜂的生命周期中起着至关重要的作用，因为它们产生苞片病毒颗粒，这些颗粒在黄蜂产卵期间被注射到被寄生的鳞翅目宿主体内。臂状病毒颗粒包衣多个编码毒力基因的dsDNA环。它们在被寄生幼虫中的表达是黄蜂成功寄生的关键。本文报道了寄生蜂Cotesia congregata基因组中原病毒片段（即用于产生被封装的dsDNA环的主序列）的基因组组织。原病毒由一个大基因座组成，包括三分之二的原病毒片段和七个分散的基因座，每个基因座包含一到三个片段。与密切相关的物种进行比较基因组分析，深入了解了臂状病毒基因组的进化动力学。不同黄蜂基因组的保守同源性表明不同物种间原病毒大位点的同源性。裸病毒基因odv-e66-like1在大基因座内保守，表明裸病毒基因组和臂状病毒前病毒片段在古代共定位。相比之下，大基因座内原病毒片段的进化涉及一系列谱系特异性重复。
Bracoviruses represent the most complex endogenous viral elements (EVEs) described to date. Nudiviral genes have been hosted within parasitoid wasp genomes since approximately 100 Ma. They play a crucial role in the wasp life cycle as they produce bracovirus particles, which are injected into parasitized lepidopteran hosts during wasp oviposition. Bracovirus particles encapsidate multiple dsDNA circles encoding virulence genes. Their expression in parasitized caterpillars is essential for wasp parasitism success. Here, we report on the genomic organization of the proviral segments (i.e. master sequences used to produce the encapsidated dsDNA circles) present in the Cotesia congregata parasitoid wasp genome. The provirus is composed of a macrolocus, comprising two-thirds of the proviral segments and of seven dispersed loci, each containing one to three segments. Comparative genomic analyses with closely related species gave insights into the evolutionary dynamics of bracovirus genomes. Conserved synteny in the different wasp genomes showed the orthology of the proviral macrolocus across different species. The nudiviral gene odv-e66-like1 is conserved within the macrolocus, suggesting an ancient co-localization of the nudiviral genome and bracovirus proviral segments. By contrast, the evolution of proviral segments within the macrolocus has involved a series of lineage-specific duplications.