VIRION
Non-enveloped, round, T=1 icosahedral symmetry, about 25 nm in diameter. The capsid consists of 12 pentagonal trumpet-shaped pentamers.
GENOME
Monopartite, circular, ssDNA genome of about 2300 bp.
The genome is replicated through double-stranded intermediates. A replication Rep-like protein would initiates rolling circle replication.
GENE EXPRESSION
One mRNA is transcribed by cellular RNA polymerase II and encodes for three proteins: VP1, VP2 and VP3 probably through leaky scanning mechanism.
REPLICATION
NUCLEAR
- Virus penetrates into the host cell.
- Uncoating, the viral ssDNA genome penetrates into the nucleus.
- Viral ssDNA is converted into dsDNA with the participation of cellular factors. dsDNA transcription gives rise to viral mRNAs.
- Viral mRNAs are translated to produce viral proteins.
- Replication may be mediated by a Rep protein, and would occur by rolling circle replication producing ssDNA genomes.
- These newly synthesized ssDNA can either
a) be converted to dsDNA and serve as a template for transcription/replication
b) be encapsidated by capsid protein and form virions released by cell lysis.
