Per os infectivity factor (IPR007784)

Short name: PIR

Overlapping homologous superfamilies


Family relationships



This entry represents a group of dsDNA Baculovirus proteins. It is required for the infectivity of the OBs or occlusion bodies. It is a structural protein of the ODV envelope required only in the first steps of per os larva infection, as viruses being produced in cells expressing the gene for this protein but not containing it in their genomes are able to produce successful infections. Baculoviruses are large DNA viruses that infect arthropods, mainly members of the order Lepidoptera. In their life cycle, they produce two kinds of particles, a budded, non-occluded virus (BV), which buds out of the infected cell and is responsible for the cell-to-cell transmission of the virus, and an occluded form, the occlusion body (OB), which is responsible for protecting the virus between encounters with larvae. A variable number of virions are included in the para-crystalline structure of the OB, mainly constituted by the virus-encoded polyhedrin protein; these virions are called occlusion body-derived virions or ODVs [PMID: 12466478].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.