Bombyx mori cypovirus encoded small peptide inhibits viral multiplication
Bombyx mori cypovirus encoded small peptide inhibits viral multiplication
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家蚕病毒编码的小肽抑制病毒增殖
DOI：
10.1016/j.dci.2019.02.017
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发表时间：
2019-07-01
影响因子：
2.9
通讯作者：
Gong, Chengliang
中科院分区：
文献类型：
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作者：
Hu, Xiaolong;Chen, Fei;Gong, Chengliang
家蚕胞质病毒（BmCPV）是呼肠孤病毒科（Reoviridae）成员，是蚕业中最具传染性的病原之一。它专门感染家蚕的中肠。BmCPV基因组由10个dsRNA片段（S1-S10）组成，通常认为它们是单顺反子的。本研究在BmCPV S5片段负链的一个区域中预测了编码S5-sORF的一个小的开放阅读框架，该框架包含27个氨基酸残基。免疫荧光法检测到S5-sORF存在于BmCPV感染细胞的细胞质和细胞核中，Western blotting法检测到S5-sORF存在于病毒粒子中，提示S5-sORF可能组装到BmCPV病毒粒子中。病毒基因表达被过表达的S5-sORF抑制，并且病毒增殖被S5-sORF肽剂量依赖性地抑制。利用反向遗传学方法，将S5-sORF的起始密码子（ATG）突变为终止密码子（TGA），获得了一株活的重组病毒BmCPV-S5-sORF（mut）。S5-sORF的表达被抑制后，BmCPV的增殖能力增强。S5-sORF的RNA转录产物和S5-sORF的小肽参与了BmCPV的复制。S5-sORF过表达对家蚕天然免疫途径和凋亡相关基因的表达没有显著影响。我们的研究结果表明，病毒的核苷酸序列被宿主利用，以产生抗病毒肽，这可能是一种新的策略，保护宿主免受病毒感染。
Bombyx mori cypovirus (BmCPV) is one of the most infectious pathogen in sericulture and a member of the family Reoviridae. It specifically infects the midgut of silkworm. The BmCPV genome consists of 10 dsRNAs segments (S1-S10), which have generally been assumed to be monocistronic. In this study, a small open reading frame encoding the peptide S5-sORF, containing 27 amino acid residues, was predicted in a region of the negative ( - ) strand of BmCPV segment S5. An immunofluorescence assay detected S5-sORF in the cytoplasm and nuclei of BmCPV-infected cells, and it was also detected in the virion with western blotting, suggesting that S5sORF may be assembled into the BmCPV virion. Viral gene expression was inhibited by overexpressed S5-sORF, and viral multiplication was dose-dependently suppressed by the S5-sORF peptide. A viable recombinant virus, BmCPV-S5-sORF(mut), in which the start codon (ATG) of S5-sORF was mutated to a stop codon (TGA), was generated with reverse genetics. The proliferation of BmCPV was increased by the abolition of S5-sORF expression. Furthermore, the RNA transcript of S5-sORF and small peptide of S5-sORF were involved in BmCPV replication. The expression of genes related to the innate immune pathways and apoptosis in the silkworm were not significantly affected by S5-sORF overexpression. Our results suggest that a viral nucleotide sequence is utilized by the host to generate an antiviral peptide, which may be a novel strategy protecting the host from viral infection.