Gene

Cell biology

Ecology

Baculoviridae

Biology

Viral replication

Virology

Glycoprotein

Botany

Larva

Genetics

Midgut

Viral envelope

Genome

Viral entry

Budding

Insect

Infectivity

Virus

Host (biology)

DNA virus

Recombinant DNA

Spodoptera

Phenotype

Annual Review of Virology

Baculoviruses are large DNA viruses of insects that are highly pathogenic in many hosts. In the infection cycle, baculoviruses produce two types of virions. These virion phenotypes are physically and functionally distinct, and each serves a critical role in the biology of the virus. One phenotype, the occlusion-derived virus (ODV), is occluded within a crystallized protein that facilitates oral infection of the host. A large complex of at least nine ODV envelope proteins called per os infectivity factors are critically important for ODV infection of insect midgut epithelial cells. Viral egress from midgut cells is by budding to produce a second virus phenotype, the budded virus (BV). BV binds, enters, and replicates in most other tissues of the host insect. Cell recognition and entry by BV are mediated by a single major envelope glycoprotein: GP64 in some baculoviruses and F in others. Entry and egress by the two virion phenotypes occur by dramatically different mechanisms and reflect a life cycle in which ODV is specifically adapted for oral infection while BV mediates dissemination of the infection within the animal.

Baculovirus Entry and Egress from Insect Cells