Baculovirus promotes occlusion-derived virus assembly by inducing nuclear lamina disruption

The nuclear lamina represents a natural barrier to the replication of many DNA viruses. Baculoviruses are important insect pathogens and microbial insecticides. They produce two types of virions during their life cycle: budded virus (BV) and occlusion-derived virus (ODV). Our previous study has clarified the effect of nuclear lamina disruption on BV production, but its role in ODV assembly remains unclear. This study aims to reveal the effect of nuclear lamina disruption on baculovirus ODV assembly, thereby further elucidating the mechanism underlying efficient baculovirus infection in insects.

Transmission electron microscopy was used to examine intranuclear microvesicle formation and ODV assembly in baculovirus-infected insect cells treated with a cyclin-dependent kinase 1 inhibitor to inhibit nuclear lamina disruption.

Inhibition of nuclear lamina disruption did not affect the nucleocapsid transport to the ring zone, but significantly reduced intranuclear microvesicle formation and led to the abnormal accumulation of nucleocapsid-attached vesicle intermediates, ultimately resulting in the inhibition of ODV assembly.

The nuclear lamina serves as a natural physical barrier to ODV morphogenesis in baculovirus-infected insect cells. Baculoviruses overcome this barrier by inducing nuclear lamina disruption, thereby promoting intranuclear microvesicle formation and ODV assembly, and ultimately facilitating their efficient proliferation in insect hosts. This study provides a theoretical foundation for further understanding the molecular mechanisms of baculovirus infection in insects.