Laboratory of Sericulture and Entomoresources, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, 464-8601, Japan.
Sci Rep. 2017 Jun 19;7(1):3807. doi: 10.1038/s41598-017-03710-z.
Baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) replicates in both Spodoptera frugiperda Sf21 and Trichoplusia ni Tn368 cells, whereas AcMNPV defective in hcf-1 (host cell-factor 1) gene productively infects only Sf21 cells, indicating that HCF-1 is indispensable for the AcMNPV productive infection of Tn368 cells. Here, we demonstrated that HCF-1 protein transiently expressed in Tn368 cells promotes the DNA synthesis of Hyphantria cunea MNPV (HycuMNPV), Orygia pseudotsugata MNPV and Bombyx mori NPV, which are normally unable to replicate in Tn368 cells. We also demonstrated that a recombinant HycuMNPV harboring the hcf-1 gene successfully replicates in Tn368 cells, generating substantial yields of progeny viruses and polyhedra. These results indicate that HCF-1 encoded by AcMNPV is an essential viral factor for productive NPV infection of Tn368 cells. Taken together with the previous findings on HRF-1 (host range factor 1), the present results provide strong evidence that viral genes acquired through horizontal gene transfer play an important role in baculovirus evolution, serving to expand the host range of baculoviruses.
杆状病毒 Autographa californica 多角体核型多角体病毒（AcMNPV）在 Spodoptera frugiperda Sf21 和 Trichoplusia ni Tn368 细胞中均能复制，而 hcf-1（宿主细胞因子 1）基因缺失的 AcMNPV 则能有效地感染 Sf21 细胞，这表明 HCF-1 是 AcMNPV 对 Tn368 细胞有效感染所必需的。在这里，我们证明了在 Tn368 细胞中瞬时表达的 HCF-1 蛋白促进了舞毒蛾多核型多角体病毒（Hyphantria cunea MNPV）、茶尺蠖多核型多角体病毒和家蚕核型多角体病毒的 DNA 合成，而这些病毒通常无法在 Tn368 细胞中复制。我们还证明了携带 hcf-1 基因的重组 HycuMNPV 能够在 Tn368 细胞中成功复制，产生大量的子代病毒和多角体。这些结果表明，AcMNPV 编码的 HCF-1 是 AcMNPV 对 Tn368 细胞进行有效 NPV 感染所必需的病毒因子。结合之前关于 HRF-1（宿主范围因子 1）的研究结果，本研究结果提供了强有力的证据，表明通过水平基因转移获得的病毒基因在杆状病毒进化中发挥了重要作用，有助于扩大杆状病毒的宿主范围。
