Picornavirales, a proposed order of positive-sense single-stranded RNA viruses with a pseudo-T=3 virion architecture
Picornavirales, a proposed order of positive-sense single-stranded RNA viruses with a pseudo-T=3 virion architecture
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DOI：
10.1007/s00705-008-0041-x
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发表时间：
2008-04-01
影响因子：
2.7
通讯作者：
Gorbalenya, Alexander E.
中科院分区：
文献类型：
--
作者：
Le Gall, Olivier;Christian, Peter;Gorbalenya, Alexander E.
尽管“小核糖核酸样”病毒有明显的自然分组，但这个假定的“超级组”的分类学意义从未得到充分的解决。我们最近向ICTV提出，应该创建一个命令并命名为小核糖核酸病毒目，以包括感染具有相似特性的真核生物的病毒：（i）通常具有5 ′-结合VPg和3 ′-聚腺苷酸化的正义RNA基因组，（ii）基因组翻译成自体蛋白水解加工的多聚蛋白，（iii）衣壳蛋白，其组织在含有三个相关的包绕结构域的模块中，所述包绕结构域形成具有假T = 3对称性的小的二十面体的无包膜颗粒，和（iv）含有超家族III解旋酶、具有胰凝乳蛋白酶样折叠的（半胱氨酸）蛋白酶和RNA依赖性RNA聚合酶的三结构域模块。根据上述标准，小核糖核酸病毒目包括小核糖核酸病毒科、Comoviridae、双链病毒科、Marnaviridae、Equiviridae和未分配的Cheravirus、Iflavirus和Sadwavirus属。其他小核糖核酸样病毒的分类群，如马铃薯Y病毒科、杯状病毒科、贫病毒科，不符合上述几个标准，并且关系较远：因此它们不被提议为新目的成员。新描述的病毒，尚未被ICTV分配到现有的分类单元，可能属于拟议的目的。
Despite the apparent natural grouping of "picorna-like" viruses, the taxonomical significance of this putative "supergroup" was never addressed adequately. We recently proposed to the ICTV that an order should be created and named Picornavirales, to include viruses infecting eukaryotes that share similar properties: (i) a positive-sense RNA genome, usually with a 5'-bound VPg and 3'-polyadenylated, (ii) genome translation into autoproteolytically processed polyprotein(s), (iii) capsid proteins organized in a module containing three related jelly-roll domains which form small icosahedral, non-enveloped particles with a pseudo-T = 3 symmetry, and (iv) a three-domain module containing a superfamily III helicase, a (cysteine) proteinase with a chymotrypsin-like fold and an RNA-dependent RNA polymerase. According to the above criteria, the order Picornavirales includes the families Picornaviridae, Comoviridae, Dicistroviridae, Marnaviridae, Sequiviridae and the unassigned genera Cheravirus, Iflavirus and Sadwavirus. Other taxa of "picorna-like" viruses, e.g. Potyviridae, Caliciviridae, Hypoviridae, do not conform to several of the above criteria and are more remotely related: therefore they are not being proposed as members of the new order. Newly described viruses, not yet assigned to an existing taxon by ICTV, may belong to the proposed order.