School of Biology & Basic Medical Science, Soochow University, Suzhou, 215123, China.
National Engineering Laboratory for Modern Silk, Soochow University, Suzhou, 215123, China.
Appl Microbiol Biotechnol. 2021 Aug;105(14-15):6019-6031. doi: 10.1007/s00253-021-11456-y. Epub 2021 Jul 29.
Claudin-2 is a major component of tight junctions (TJs), which play an important role in reovirus entry into host cells. The Bombyx mori cytoplasmic polyhedosis virus (BmCPV) relates to the cypovirus strain of the reovirus family. So far, the role of claudin-2 in the process of BmCPV infection is not known. In the present study, it was observed that increasing expression of the claudin-2 gene (CLDN2) may concomitantly elevate BmCPV infection. Contrarily, knockdown of CLDN2 expression by siRNAs can reduce BmCPV infection. Similarly, antibody-based blockage of claudin-2 could also decrease BmCPV cell entry. These results suggest that claudin-2 can promote BmCPV infection in vitro. Moreover, immunofluorescence (IF) assays showed that claudin-2 can interact with BmCPV during viral infection. Specifically, co-immunoprecipitation experiments indicated that claudin-2 binds the BmCPV VP7 (instead of VP3 proteins). The interaction between VP7 and claudin-2 was further confirmed by bimolecular fluorescence complementation (BIFC). Altogether, our results suggest that BmCPV cell entry can be promoted upon interaction of VP7 with claudin-2. These findings provide new mechanistic insights related to BmCPV infection. KEY POINTS: •Claudin-2 could promote BmCPV infection of cells. •Claudin-2 interacted with BmCPV during BmCPV infection. •Claudin-2 could interact with BmCPV VP7 protein, but not with VP3 proteins.
紧密连接（TJ）的主要成分之一是 Claudin-2，它在呼肠孤病毒进入宿主细胞中发挥重要作用。家蚕质型多角体病毒（BmCPV）与呼肠孤病毒科的 Cypovirus 株有关。到目前为止，Claudin-2 在 BmCPV 感染过程中的作用尚不清楚。在本研究中，观察到 Claudin-2 基因（CLDN2）的表达增加可能同时提高 BmCPV 的感染。相反，通过 siRNA 敲低 CLDN2 的表达会降低 BmCPV 的感染。同样，基于抗体的 Claudin-2 阻断也可以减少 BmCPV 进入细胞。这些结果表明 Claudin-2 可以促进 BmCPV 在体外感染。此外，免疫荧光（IF）检测表明 Claudin-2 可以在病毒感染过程中与 BmCPV 相互作用。具体而言，共免疫沉淀实验表明 Claudin-2 结合 BmCPV 的 VP7（而非 VP3 蛋白）。双分子荧光互补（BIFC）进一步证实了 VP7 与 Claudin-2 之间的相互作用。总之，我们的结果表明，VP7 与 Claudin-2 的相互作用可以促进 BmCPV 进入细胞。这些发现为 BmCPV 感染提供了新的机制见解。关键点：•Claudin-2 可以促进 BmCPV 感染细胞。•Claudin-2 在 BmCPV 感染过程中与 BmCPV 相互作用。•Claudin-2 可以与 BmCPV 的 VP7 蛋白相互作用，但不能与 VP3 蛋白相互作用。
