IRD, UR 072, Laboratoire Evolution, Génomes et Spéciation, UPR 9034, CNRS, 91198 Gif-sur-Yvette Cedex, France.
Virology. 2010 Feb 5;397(1):145-54. doi: 10.1016/j.virol.2009.10.042. Epub 2009 Dec 1.
The Tetraviridae is a family of non-enveloped positive-stranded RNA insect viruses that is defined by the T=4 symmetry of virions. We report the complete Euprosterna elaeasa virus (EeV) genome sequence of 5698 nt with no poly(A) tail and two overlapping open reading frames, encoding the replicase and capsid precursor, with approximately 67% amino acid identity to Thosea asigna virus (TaV). The N-terminally positioned 17 kDa protein is released from the capsid precursor by a NPGP motif. EeV has 40 nm non-enveloped isometric particles composed of 58 and 7 kDa proteins. The 3'-end of TaV/EeV is predicted to form a conserved pseudoknot. Replicases of TaV and EeV include a newly delineated VPg signal mediating the protein priming of RNA synthesis in dsRNA Birnaviridae. Results of rooted phylogenetic analysis of replicase and capsid proteins are presented to implicate recombination between monopartite tetraviruses, involving autonomization of a sgRNA, in the emergence of bipartite tetraviruses. They are also used to revise the Tetraviridae taxonomy.
四病毒科是一类具有 T=4 对称的无包膜正链 RNA 昆虫病毒，其特征为病毒粒子的四进制对称性。我们报告了全长为 5698 个核苷酸、无 poly(A)尾巴且具有两个重叠开放阅读框的东方果实蝇病毒（EeV）全基因组序列，其复制酶和衣壳前体的编码区与柑橘银纹夜蛾病毒（TaV）的约有 67%的氨基酸同一性。N 端位置的 17 kDa 蛋白通过 NPGP 基序从衣壳前体中释放出来。EeV 具有 40nm 无包膜的等轴立体颗粒，由 58 和 7 kDa 蛋白组成。预测 TaV/EeV 的 3' 端形成保守的假结。TaV 和 EeV 的复制酶包括一个新划定的 VPg 信号，介导 dsRNA 双 RNA 病毒中 RNA 合成的蛋白引发作用。基于复制酶和衣壳蛋白的系统发育分析结果表明，单分体四病毒之间的重组涉及 sgRNA 的自主化，导致了二分体四病毒的出现。它们还被用于修订四病毒科的分类法。
