Research and Education Center for Prevention of Global Infectious Disease of Animal, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan.
Azabu University, Sagamihara, Kanagawa, Japan.
Infect Genet Evol. 2019 Nov;75:103975. doi: 10.1016/j.meegid.2019.103975. Epub 2019 Jul 22.
Enterovirus G (EV-G) belongs to the family of Picornaviridae. Two types of recombinant porcine EV-Gs carrying papain-like cysteine protease (PLCP) gene of porcine torovirus, a virus in Coronaviridae, are reported. Type 1 recombinant EV-Gs are detected in pig feces in Japan, USA, and Belgium and carry the PLPC gene at the junction site of 2C/3A genes, while PLPC gene replaces the viral structural genes in type 2 recombinant EV-G detected in pig feces in a Chinese farm. We identified a novel type 2 recombinant EV-G carrying the PLCP gene with flanking sequences in place of the viral structural genes in pig feces in Japan. The ~0.3 kb-long upstream flanking sequence had no sequence homology with any proteins deposited in GenBank, while the downstream ~0.9 kb-long flanking sequence included a domain having high amino acid sequence homology with a baculoviral inhibitor of apoptosis repeat superfamily. The pig feces, where the novel type 2 recombinant EV-G was detected, also carried type 1 recombinant EV-G. The amount of type 1 and type 2 recombinant EV-G genomes was almost same in the pig feces. Although the phylogenetic analysis suggested that these two recombinant EV-Gs have independently evolved, type 1 recombinant EV-G might have served as a helper virus by providing viral structural proteins for dissemination of the type 2 recombinant EV-G.
肠道病毒 G（EV-G）属于小核糖核酸病毒科。据报道，有两种携带冠状病毒科猪传染性胃肠炎病毒木瓜蛋白酶样半胱氨酸蛋白酶（PLCP）基因的重组猪 EV-G。1 型重组 EV-G 存在于日本、美国和比利时的猪粪便中，其 PLCP 基因位于 2C/3A 基因交界处，而 2 型重组 EV-G 的 PLPC 基因取代了在中国一个农场猪粪便中检测到的病毒结构基因。我们在日本猪粪便中鉴定出一种携带侧翼序列的新型 2 型重组 EV-G，其 PLCP 基因取代了病毒结构基因。约 0.3kb 长的上游侧翼序列与 GenBank 中任何已注册的蛋白质均无序列同源性，而下游约 0.9kb 长的侧翼序列则包含一个与杆状病毒凋亡抑制剂重复超家族具有高度氨基酸序列同源性的结构域。新型 2 型重组 EV-G 检测到的猪粪便也携带 1 型重组 EV-G。猪粪便中 1 型和 2 型重组 EV-G 基因组的含量几乎相同。虽然系统进化分析表明这两种重组 EV-G 是独立进化的，但 1 型重组 EV-G 可能通过提供病毒结构蛋白促进了 2 型重组 EV-G 的传播，从而发挥了辅助病毒的作用。
