Plectroviridae (taxid:2732098)

VIRION

Non-enveloped, rod of filaments of 7-15nm in diameter and 230 to 2000nm in length. Helical capsid with adsorption proteins on one end.

GENOME

Circular, ssDNA genome (+) of 4.5 to 8kb encoding for 4 to 13 proteins. Replication occurs via dsDNA intermediate and rolling circle (Plectrovirus, Suturavirus) or by replicative transposition (Vespertilliovirus).

GENE EXPRESSION

Each gene is transcribed by host cellular machinery, via a specific promoter. Some genes end by a transcription terminator.

ENZYMES

(Plectrovirus; Suturavirus)

• Proka-type Endonuclease [Rep]
  or
  (Vespertiliovirus)
  
• Integrase/transposase? [ORF3]

REPLICATION

CYTOPLASMIC

1. Viral protein mediates binding to host membrane.
2. The proteins of the capsid perform the injection of the viral DNA through bacterial membranes into cell cytoplasm.
3. Host polymerase convert the (+)ssDNA viral genome into a covalently closed dsDNA called replicative form DNA (RF).
4. dsDNA transcription by host RNA polymerase gives rise to viral mRNAs.
5. (+) strand replication occurs by rolling circle.
6. New (+)ssDNA genomes are converted into new RF molecules, and further transcription occurs.
7. Viral proteins interaction with ssDNA genome trigger the assembly of the viral capsid.
8. New virions are secreted from host cell.