Hepatitis E virus (HEV) infects humans and more than a dozen other animal species. We previously showed that open reading frame 2 (ORF2) and ORF3 are apparently not involved in HEV cross‐species infection, which infers that the ORF1 may contribute to host tropism. In this study, we utilize the genomic backbone of HEV‐1 which only infects humans to construct a panel of intergenotypic chimeras in which the entire ORF1 gene or its functional domains were swapped with the corresponding regions from HEV‐3 that infects both humans and pigs. We demonstrated that the chimeric HEVs were replication competent in human liver cells. Subsequently, we intrahepatically inoculated the RNA transcripts of chimeras into pigs to determine if the swapped ORF1 regions confer the chimeras’ ability to infect pigs. We showed that there was no evidence of infectivity in pigs for any of the chimeras. We also investigated the role of human ribosome protein sequence S17, which expanded host range in cultured cells, in HEV cross‐species infection. We demonstrated that S17 insertion in HEV ORF1 did not abolish HEV replication competency in vitro, but also did not expand HEV host tropism in vivo. The results highlight the complexity of the underlying mechanism of HEV cross‐species infection.

中文翻译：

---

利用基因型嵌合病毒剖析戊型肝炎病毒ORF1非结构基因在跨物种感染中的潜在作用。

戊型肝炎病毒 (HEV) 感染人类和十多种其他动物物种。我们之前表明开放阅读框2（ORF2）和ORF3显然不参与HEV跨物种感染，这推断ORF1可能有助于宿主向性。在这项研究中，我们利用仅感染人类的​​ HEV-1 的基因组骨架构建了一组基因型间嵌合体，其中整个 ORF1 基因或其功能域与感染人类和猪的 HEV-3 的相应区域进行交换。我们证明嵌合 HEV 在人肝细胞中具有复制能力。随后，我们将嵌合体的RNA转录物肝内接种到猪体内，以确定交换的ORF1区域是否赋予嵌合体感染猪的能力。我们发现没有证据表明任何嵌合体对猪具有感染性。我们还研究了人类核糖体蛋白序列 S17 在 HEV 跨物种感染中的作用，该序列扩大了培养细胞中的宿主范围。我们证明，在 HEV ORF1 中插入 S17 并不会消除 HEV 体外复制能力，也不会在体内扩大 HEV 宿主向性。结果凸显了 HEV 跨物种感染潜在机制的复杂性。