Molecular biology
VIRION
Non-enveloped, icosahedral capsid with a T=7d symmetry, about 45 nm in diameter.
GENOME
Circular dsDNA about 5 kb in size, associated with cellular histones in a chromatin-like complex. Encodes for 5-9 proteins.
GENE EXPRESSION
Transcription is nuclear, in two phases; early (replication), late (virion assembly). All genes are transcribed by host RNA pol II.
REPLICATION
NUCLEAR
- Virus attaches to host receptors and is endocytosed into vesicles in the host cell.
- Virion transits through endoplasmic reticulum where host protein disulfide isomerases rearrange its capsid structure
- Export of misfolded virion to the cytoplasm possibly through host ERAD pathway
- Loss of VP1 in the low-calcium conditions of the cytosol
- Import of genomic DNA into host nucleus.
- Transcription of early genes (LT and sT genes)
- Replication of the DNA genome in the nucleus.
- Transcription of late genes encoding for structural proteins (VP1, VP2 and VP3).
- Assembly of new virions in the nucleus.
- Virions are released by lysis of the cell.