Nuclear F-actin is required for AcMNPV nucleocapsid morphogenesis

During nucleocapsid assembly, filamentous actin (F-actin) colocalizes with the major capsid protein of Autographa californica M nucleopolyhedrovirus ( AcMNPV) within nuclei of infected lepidopteran host cells. Cytochalasin D ( CD) disrupts actin filaments and prevents assembly of progeny AcMNPV, sugge sting that nuclear F-actin is essential for nucleocapsid morphogenesis. Dir ect proof for this hypothesis was provided by the demonstration that two Ac MNPV recombinants engineered to express either wild-type- or CD-resistant a ctin:at equivalent rates were differentially sensitive to CD. The AcMNPV re quirement for nuclear F-actin is unique among intracellular pathogens and m ay constitute a significant host range factor, (C) 1999 Academic Press.