AcMNPV Core Gene ac109 Is Required for Budded Virion Transport to the Nucleus and for Occlusion of Viral Progeny

Abstract

Autographa californica multiple nucleopolyhedrovirus (AcMNPV) ac109 core gene hasbeen previously characterized as an essential late gene. Our results showed thatbudded virions could be detected in supernatants of infected Sf-9 cells, even whenac109 knockout viruses displayed a single-cell infection phenotype. Moreover, confocalmicroscopy analysis revealed that budded virions can enter the cytoplasm but areunable to enter the cell nucleus. This defect could be repaired by complementingac109 in trans. In addition, polyhedra of normal size could be detected in Sf-9 nucleiinfected with ac109 knockout viruses. However, electron microscopy demonstratedthat these occlusion bodies were empty. Altogether these results indicate that ac109 isrequired for infectivity of both phenotypes of virus.