Tight junction protein claudin-2 promotes cell entry of Bombyx mori cypovirus

• Published in: Applied microbiology and biotechnology 2021-08, Vol.105 (14-15), p.6019-6031
• Main Authors: Zhu, Min, Zhang, Xing, Pan, Jun, Zhu, Hanxue, Zhang, Ziyao, Liang, Zi, Cao, Guangli, Hu, Xiaolong, Xue, Renyu, Gong, Chengliang
• Format: Article
• Language: English
• Subjects: Antibodies; Applied Microbial and Cell Physiology; Biomedical and Life Sciences; Biotechnology; Bombyx mori; Complementation; Fluorescence; Gene expression; Health aspects; Immunofluorescence; Immunoprecipitation; Infections; Life Sciences; Membrane proteins; Microbial Genetics and Genomics; Microbiology; Physiological aspects; Proteins; Reoviruses; Silkworms; siRNA; Tight junctions; VP3 protein; VP7 protein
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-021-11456-y

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 .