Fromanvirus

VIRION

Non-enveloped, head-tail structure. The capsid is icosahedral, about 60nm in diameter. The capsid proteins are covalently linked. Tail is flexible, about 135 nm in length and 8 nm in width, with a terminal knob and a single short fiber.

GENOME

Linear, dsDNA genome of about 52 kb, containing about 88 genes. The genome has cohesive ends (cos sites).

GENE EXPRESSION

REPLICATION

CYTOPLASMIC

  1. Adsorption: The phage attaches to target cell adhesion receptors through its tail fibers.
  2. Ejection of the viral DNA into host cell cytoplasm by long flexible tail ejection system.
  3. Transcription and translation of early genes.
  4. Shutoff of host gene expression, possibly by gp77, gp78 and gp79.
  5. Replication of genomic DNA by rolling circle.
  6. Transcription and translation of late genes
  7. Assembly of an empty procapsid and packaging of the genome.
  8. Viral tail fiber assembly and viral tail assembly.
  9. Mature virions are released from the cell by lysis.