Nonhomologous recombination between defective poliovirus and coxsackievirus genomes suggests a new model of genetic plasticity for picornaviruses.
Nonhomologous recombination between defective poliovirus and coxsackievirus genomes suggests a new model of genetic plasticity for picornaviruses.
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DOI：
10.1128/mbio.01119-14
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发表时间：
2014-08-05
期刊：
影响因子：
6.4
通讯作者：
Delpeyroux F
中科院分区：
文献类型：
--
作者：
Holmblat B;Jégouic S;Muslin C;Blondel B;Joffret ML;Delpeyroux F
与马达加斯加脊髓灰质炎暴发有关的大多数流行疫苗衍生脊髓灰质炎病毒(CVDPV)已被证明是口服脊髓灰质炎疫苗(Sabin 2)的2型脊髓灰质炎病毒(PV)毒株与另一种C类人类肠道病毒(HEV-C)之间的重组病毒，特别是17型柯萨奇A型病毒(CA17)。我们通过建立重组模型研究了PV和非PV HEV-C之间的异型遗传交换，通过将缺陷或感染性CA17 RNA与细胞共转染，可以挽救3‘端短缺失的2型PV RNA基因组。我们分离了200多种不同的PV/CA17重组体，使用表达人PV受体(PVR)的小鼠细胞，并选择具有PV衣壳的病毒。我们发现一些同源(H)重组体和大部分非同源(NH)重组体优先位于编码蛋白2A、2B和3A的区域，呈现双亲序列的重复。短复制似乎是稳定的，而较长的复制在培养细胞传代过程中或在PVR转基因小鼠繁殖后被删除，产生具有不同重组位点的H重组体。这表明NH重组事件可能是产生和选择最合适的H重组子的一个瞬时的中间步骤。除了主要产生H重组子的经典重组思想的复制选择机制外，还可能存在一种模块化的重组机制，涉及NH重组前体，塑造重组肠道病毒和其他微小RNA病毒的基因组。疫苗衍生脊髓灰质炎病毒(CVDPV)在免疫力低下的人群中繁殖，可使这些病毒致病，导致脊髓灰质炎暴发。大多数cVDPV是脊髓灰质炎病毒(PV)株和另一种人类肠道病毒，如17型柯萨奇A型病毒(CA17)之间的异型重组体。为了进一步研究PV和CA17之间的遗传交换，我们建立了一个重组模型，通过将缺失的PV基因组与CA17基因组RNA共转染细胞，可以挽救具有短缺失的PV RNA基因组。发现了许多重组体，包括同源的PV/CA17重组体，但大多数非同源重组体呈现优先位于特定区域的双亲序列的重复。在培养的细胞或小鼠中，通过传代切除长的复制，产生不同的同源重组体。因此，导致非同源重组体的重组可以被视为肠道病毒以及可能在其他RNA病毒中遗传可塑性的模型。
Most of the circulating vaccine-derived polioviruses (cVDPVs) implicated in poliomyelitis outbreaks in Madagascar have been shown to be recombinants between the type 2 poliovirus (PV) strain of the oral polio vaccine (Sabin 2) and another species C human enterovirus (HEV-C), such as type 17 coxsackie A virus (CA17) in particular. We studied intertypic genetic exchanges between PV and non-PV HEV-C by developing a recombination model, making it possible to rescue defective type 2 PV RNA genomes with a short deletion at the 3′ end by the cotransfection of cells with defective or infectious CA17 RNAs. We isolated over 200 different PV/CA17 recombinants, using murine cells expressing the human PV receptor (PVR) and selecting viruses with PV capsids. We found some homologous (H) recombinants and, mostly, nonhomologous (NH) recombinants presenting duplications of parental sequences preferentially located in the regions encoding proteins 2A, 2B, and 3A. Short duplications appeared to be stable, whereas longer duplications were excised during passaging in cultured cells or after multiplication in PVR-transgenic mice, generating H recombinants with diverse sites of recombination. This suggests that NH recombination events may be a transient, intermediate step in the generation and selection of the fittest H recombinants. In addition to the classical copy-choice mechanism of recombination thought to generate mostly H recombinants, there may also be a modular mechanism of recombination, involving NH recombinant precursors, shaping the genomes of recombinant enteroviruses and other picornaviruses. The multiplication of circulating vaccine-derived polioviruses (cVDPVs) in poorly immunized human populations can render these viruses pathogenic, causing poliomyelitis outbreaks. Most cVDPVs are intertypic recombinants between a poliovirus (PV) strain and another human enterovirus, such as type 17 coxsackie A viruses (CA17). For further studies of the genetic exchanges between PV and CA17, we have developed a model of recombination, making it possible to rescue defective PV RNA genomes with a short deletion by cotransfecting cells with the defective PV genome and CA17 genomic RNA. Numerous recombinants were found, including homologous PV/CA17 recombinants, but mostly nonhomologous recombinants presenting duplications of parental sequences preferentially located in particular regions. Long duplications were excised by passages in cultured cells or in mice, generating diverse homologous recombinants. Recombination leading to nonhomologous recombinants, which evolve into homologous recombinants, may therefore be seen as a model of genetic plasticity in enteroviruses and, possibly, in other RNA viruses.