Molecular biology
VIRION
Envelopped. extracellular baculovirus virions can be found in two forms: OV (occluded virus) and BV (budded virus).
GENOME
Circular dsDNA, 80-180 kb in length, encoding for 100 to 180 proteins.
GENE EXPRESSION
REPLICATION
NUCLEUS
- Virus attaches to host receptors.
- Fusion of virus membrane with the vesicle membrane occurs; DNA genome is released into the nucleus.
- Immediate early phase: host RNA polymerase transcribes viral genes involved in the regulation of the replication cascade, prevention of host responses and viral DNA synthesis.
- Late phase: The virally encoded RNA polymerase expresses late genes.
- Shutdown of host cell transcription.
- Replication of the genome by rolling circle.
- Nucleocapsids are formed which can either bud out through the cellular membrane and disseminate the infection or be occluded for horizontal transmission.
- Occlusion phase: the virus becomes occluded in the protein polyhedrin and the polyhedral envelope (calyx) is produced. Lysis of the cell releases the occluded virus.