Bombyx mori Akirin hijacks a viral peptide vSP27 encoded by BmCPV circRNA and activates the ROS-NF-κB pathway against viral infection

Bombyx mori cypovirus (BmCPV), a member of the family Reoviridae, is a model of Cypovirus, has a 10 segmented double-stranded RNA genome. However, so far, only one viral small peptide vSP27 with negative regulation on viral infection was identified; the mechanisms underlying host-BmCPV interaction are still unknown. Here, we identified that vSP27 was translated from a BmCPV derived circular RNA (circRNA-vSP27). Subsequently, results showed that vSP27 induced generation of ROS activated the NF-kappa B signaling pathway, induced the expression of antimicrobial peptides, and suppressed BmCPV infection. On the other hand, we identified a nuclear protein Akirin that could hijack vSP27, positively regulate the NF-kappa B pathway, and lead to inhibiting the viral infection. Altogether, our data suggested that BmCPV derived circRNA-vSP27 with small peptide translation activity may be employed by the host immunity in defense against the BmCPV infection.

Automated summary

The study identified that vSP27 of BmCPV is translated from a circular RNA and can suppress viral infection by inducing ROS generation, activating the NF-kappa B signaling pathway, and promoting the expression of antimicrobial peptides. Additionally, a nuclear protein Akirin was found to interact with vSP27, positively regulate the NF-kappa B pathway, and inhibit viral infection. These findings suggest that the BmCPV-derived circRNA-vSP27 may play a role in host immunity against BmCPV infection.