Olendraite Ingrida, Lukhovitskaya Nina I, Porter Sanford D, Valles Steven M, Firth Andrew E
Division of Virology, Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK.
Center for Medical, Agricultural and Veterinary Entomology, USDA-ARS, 1600 SW 23rd Drive, Gainesville, FL 32608, USA.
J Gen Virol. 2017 Sep;98(9):2368-2378. doi: 10.1099/jgv.0.000902. Epub 2017 Aug 31.
Solenopsis invicta virus 2 is a single-stranded positive-sense picorna-like RNA virus with an unusual genome structure. The monopartite genome of approximately 11 kb contains four open reading frames in its 5' third, three of which encode proteins with homology to picornavirus-like jelly-roll fold capsid proteins. These are followed by an intergenic region, and then a single long open reading frame that covers the 3' two-thirds of the genome. The polypeptide translation of this 3' open reading frame contains motifs characteristic of picornavirus-like helicase, protease and RNA-dependent RNA polymerase domains. An inspection of public transcriptome shotgun assembly sequences revealed five related apparently nearly complete virus genomes isolated from ant species and one from a dipteran insect. By high-throughput sequencing and in silico assembly of RNA isolated from Solenopsis invicta and four other ant species, followed by targeted Sanger sequencing, we obtained nearly complete genomes for four further viruses in the group. Four further sequences were obtained from a recent large-scale invertebrate virus study. The 15 sequences are highly divergent (pairwise amino acid identities of as low as 17 % in the non-structural polyprotein), but possess the same overall polycistronic genome structure, which is distinct from all other characterized picorna-like viruses. Consequently, we propose the formation of a new virus family, Polycipiviridae, to classify this clade of arthropod-infecting polycistronic picorna-like viruses. We further propose that this family be divided into three genera: Chipolycivirus (2 species), Hupolycivirus (2 species) and Sopolycivirus (11 species), with members of the latter infecting ants in at least 3 different subfamilies.
红火蚁病毒2是一种单链正义的类微小核糖核酸病毒，其基因组结构不同寻常。约11kb的单分体基因组在其5'端三分之一区域含有四个开放阅读框，其中三个编码与微小核糖核酸病毒样果冻卷折叠衣壳蛋白具有同源性的蛋白质。随后是一个基因间隔区，接着是一个覆盖基因组3'端三分之二区域的单一长开放阅读框。这个3'端开放阅读框的多肽翻译包含微小核糖核酸病毒样解旋酶、蛋白酶和依赖RNA的RNA聚合酶结构域的特征基序。对公共转录组鸟枪法组装序列的检查发现，从蚁类物种中分离出了五个相关的、显然近乎完整的病毒基因组，还有一个来自双翅目昆虫。通过对从红火蚁和其他四种蚁类物种中分离的RNA进行高通量测序和电子组装，随后进行靶向桑格测序，我们获得了该病毒组中另外四种病毒的近乎完整的基因组。另外四个序列来自最近一项大规模的无脊椎动物病毒研究。这15个序列高度分化（非结构多聚蛋白中的氨基酸两两同一性低至17%），但具有相同的整体多顺反子基因组结构，这与所有其他已鉴定的类微小核糖核酸病毒不同。因此，我们提议形成一个新的病毒科——多顺反子病毒科，以对这一感染节肢动物的多顺反子类微小核糖核酸病毒进化枝进行分类。我们还提议将这个科分为三个属：芯片多顺反子病毒属（2个物种）、胡多顺反子病毒属（2个物种）和索多顺反子病毒属（11个物种），后一属的成员感染至少3个不同亚科的蚂蚁。
