Corticoviridae (taxid:10659)

VIRION

Icosahedral pseudo T=21 capsid 56 nm in diameter, composed of 1200 P1 (spike) and 60 P2 (capsid) proteins. The pentameric receptor-binding spikes are protruding from the 12 fivefold axes. The capsid encloses an internal lipid core containing the structural proteins P3 to P9.

• Double jelly roll-fold major capsid protein [MCP P2]
• Triple jelly roll-fold penton capsid protein [Spike P1]

GENOME

Circular, supercoiled dsDNA genome of about 10 kb encoding for 21 proteins. Displays a very high number of negative supercoils.

GENE EXPRESSION

The genome is organized in three operons.

ENZYMES

• Proka-type Endonuclease [P12 rep]

REPLICATION

CYTOPLASMIC

1. Adsorption: the phage attach to target cell
2. Injection: viral DNA is injected in host cell cytoplasm
3. Transcription and translation of early genes
4. Replication of genomic DNA via a rolling-circle mechanism
5. Transcription and translation of late genes
6. Capsid proteins polymerize around a lipoprotein vesicle translocated in the cytoplasm by virion assembly factors.
7. Genomic DNA is packaged in new virions
8. Mature virions are released from the cell by lysis