Non-enveloped, round, T=1 icosahedral symmetry, 21-22 nm in diameter. The capsid consists of 60 copies of CP protein.
Linear, ssDNA genome of about 4kb in size, with long inverted terminal repeats. Both positive and negative strands are encapsidated, but a majority of strands are of negative polarity (85%).
The genome is replicated through rolling-hairpin mechanism.
Host proteins transcribe the genomes into mRNAs.
- Attachement to host receptors initiates clathrin-mediated endocytosis of the virion into the host cell.
- The virion penetrates into the cytoplasm via permeabilization of host endosomal membrane.
- Microtubular transport of the virion toward the nucleus.
- The viral ssDNA genome penetrates into the nucleus.
- The ssDNA is converted into dsDNA by cellular proteins.
- dsDNA transcription gives rise to viral mRNAs when host cell enters S phase and translated to produce viral proteins.
- Replication occurs through rolling-hairpin mechanism, with NS1 endonuclease binding covalently to the 5’ genomic end.
- Individual ssDNA genomes are excised from replication concatemers by a process called junction resolution.
- These newly synthesized ssDNA can either
a) be converted to dsDNA and serve as a template for transcription/replication
b) be encapsidated to form new virions that are released from the cell by budding.