Non-enveloped, round, T=1 icosahedral symmetry, about 30 nm in diameter. The capsid consists of 12 pentagonal trumpet-shaped pentomers. The virion is composed of 60 copies each of the F, G, and J proteins, and 12 copies of the H protein. There are 12 spikes which are each composed of 5 G and one H proteins.
Circular, ssDNA(+) genome of 4.5kb. Replication occurs via dsDNA intermediate and rolling circle.
Early and late genes promoters tightly regulates the timing of gene expression, which is crucial for the replication cycle.
- The viral particle attaches to host cell by binding host lipopolysaccharides.
- The proteins of the capsid perform Injection of the viral DNA through bacterial membranes into cell cytoplasm.
- Host polymerase convert the (+)ssDNA viral genome into a covalently closed dsDNA called replicative form DNA I (RF-I).
- Early viral genes are transcribed by host RNA polymerase, producing viral replication proteins.
- Viral protein A cleaves RF-I(+) DNA strand at the origin of replication and covalently attaches itself to the DNA.
- (+)strand replication occurs by rolling circle, which is converted to dsDNA by host polymerase, generating RF-II molecules (amplification of RF-I).
- Late viral genes are transcribed by host RNA polymerase.
- Procapsid assembly in the cytoplasm.
- Viral protein C binds to replication complex, inducing synthesis and packaging of neo-synthesized (+)ssDNA genomes (RF-III) into procapsids.
- Procapsids maturation occurs in host cytoplasm
- Mature virions are released from the cell by lysis.