BmeIF4E2 promotes AcMNPV infection in the silkworm, Bombyx mori, by direct interaction.

The molecular mechanism of baculovirus infection is the basis of baculovirus wide application. Identifying and elucidating the functional genes of virus replication is the focus of research. Eukaryotic initiation factor 4E (eIF4E) is a key component of the translation initiation process to synthesize proteins required for replication. Our pre-transcriptomics data suggest that BmeIF4E is associated with Autographacalifornica nucleopolyhedrovirus (AcMNPV) infection, but its exact role is unknown. The study first clarified, using bioinformatics, that the function of BmeIF4E2 is highly conserved, and expression profile analysis revealed that the high expression of BmeIF4E2 is mainly distributed in the egg stage, 4th instar molting stage, and pupal stage. To clarify the function of BmeIF4E2 in AcMNPV infestation, it was overexpressed and interfered in BmN cells. The increase of virus after overexpression and decrease of virus after interference indicated that BmeIF4E2 could promote AcMNPV infection. To analyze whether BmeIF4E2 is directly involved in promoting AcMNPV infection, His-tag pull down analysis was performed with prokaryotic expression of BmeIF4E2 protein as bait. It was found that BmeIF4E2 could interact directly with vAcMNPV-eGFP. Finally, we validated this in individual silkworms using the inhibitor 4E2RCat and the recombinant virus AcMNPV-BmeIF4E2, and the results were consistent with those obtained in cells. Thus, BmeIF4E2 is a key gene that promotes AcMNPV infection in silkworms via direct interaction. The results are valuable for pest biological control and improving the yield of baculovirus expression systems.