Molecular mechanisms in caterpillar baculovirus infections

Baculoviruses are double-stranded DNA, enveloped viruses which infect the larval stage of lepidoptera.  As such, they have been studied as potential biocontrol agents and are used worldwide for pest control for forest insects and crops such as cotton and soybean.  Baculoviruses exhibit interesting pathology in infected caterpillars- for example they induce a walking behavior during infection, block molting, and liquefy the cadaver after death.  At the cellular level, we have found that baculoviruses (specifically Autographa californica M nucleopolyhedrovirus) manipulate the actin cytoskeleton of the host in striking ways.  After entry into the cell cytoplasm, viral nucleocapsids utilize actin-based motility to propel them about the cell.  And following nuclear entry, viral early genes cause numerous alterations to the host cytoskeleton, including an aggregation of actin around the cell periphery and nuclear translocation of soluble actin monomers.  As the virus replicates, nuclear actin polymerizes into filaments, which contributes both to the structure of viral replication centers as well as allowing virus escape from the nucleus, and ultimately from the cell, to spread the infection.