Polydnaviriformidae (taxid:2946196)

VIRION

Enveloped, prolate ellipsoid form (ichnoviriform) and cylindrical (bracoviriform). Depending on the species, a virion contains one or several nucleocapsids.

GENOME

Segmented, circular supercoiled dsDNAs ranging from 2.0-31kb. Each virion contains multiple copies of the genome.

GENE EXPRESSION

REPLICATION

NUCLEAR

a) replicative: occurs in the calyx cells of the ovary.

1. Excision and circularization of viral DNA in the ovary cells.
2. Viral DNA synthesis.
3. Appearance of viral envelopes and nucleocapsids in the nucleus.
4. Mature virions are released into the lumen of the oviduct probably by lysis (brachoviriform) or budding through the cell membrane (ichnoviriform).

b) vegetative: occurs in all non-reproductive cells.

The viral genome is transmitted in proviral linear form integrated in the wasp's chromosomes. The virus DNA is replicated, just like any other part of the wasp's genome.

Host-virus interaction

Apoptosis modulation

PTP-H2 triggers mitochondrial membrane depolarization and caspase-dependent apoptosis suggesting that apoptosis is induced through a mitochondria-dependent death pathway.

NF-kappa-B modulation

Polydnavirus Ank proteins bind NF-kappa-B homodimers and inhibit processing of relish/NF-kappa-B p110 subunit .

Innate immune response inhibition

Microplitis demolitor cracovirus PTP-H2 and PTP-H3 are functional tyrosine phosphatases whose expression inhibit phagocytosis . Another protein, Glc1.8 is also involved in suppression of the insect cellular immune response .