Non-enveloped, rod of filaments of 7 nm in diameter and 1000 to 1200nm long in length. Helical capsid with adsorption proteins on one end.


Circular, ssDNA genome (+) of 6.3 to 7.5 kb encoding for 12 to 15 proteins. Replication occurs via dsDNA intermediate and rolling circle.


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



  1. Virus mediates pilus-mediated adsorption of the virus onto host cell. Pilus retraction pulls the virion to the host internal 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. A viral protein may nick RF DNA strand at the origin of replication.
  6. (+) strand replication occurs by rolling circle.
  7. New (+)ssDNA genomes are converted into new RF molecules, and further transcription occurs.
  8. A conversion into RF dsDNA is inhibited, as neo-synthesized genomic ssDNA is covered with a viral protein.
  9. Assembly of the viral capsid.
  10. New virions are secreted from host cell.
  11. Infected cells continue to divide and produce virions indefinitely.

Matching UniProtKB/Swiss-Prot entries

25 entries grouped by strain (browse by keywords)

13 entries

Spiroplasma virus SpV1-C74 (SpV1) reference strain

ORF7_SPV1C Uncharacterized protein ORF7
ORF4_SPV1C Uncharacterized protein ORF4
ORF13_SPV1C Uncharacterized protein ORF13
ORF2_SPV1C Uncharacterized protein ORF2
ORF1_SPV1C Uncharacterized protein ORF1
ORF14_SPV1C Uncharacterized protein ORF14
ORF15_SPV1C Uncharacterized protein ORF15
ORF10_SPV1C Uncharacterized protein ORF10
ORF5_SPV1C Uncharacterized protein ORF5
ORF12_SPV1C Uncharacterized protein ORF12
ORF11_SPV1C Uncharacterized protein ORF11
INTG_SPV1C Putative integrase ORF3
CAPSD_SPV1C Putative capsid protein ORF9

12 entries

Spiroplasma virus SpV1-R8A2 B (SpV1) (Spiroplasma virus 1) reference strain

CAPSD_SPV1R Putative capsid protein ORF9 (Gene 9 protein)
ORF4_SPV1R Uncharacterized protein ORF4 (Gene 4 protein)
ORF12_SPV1R Uncharacterized protein ORF12 (Gene 12 protein)
ORF8_SPV1R Uncharacterized protein ORF8 (Gene 8 protein)
ORF2_SPV1R Uncharacterized protein ORF2 (Gene 2 protein)
ORF11_SPV1R Uncharacterized protein ORF11 (Gene 11 protein)
ORF10_SPV1R Uncharacterized protein ORF10 (Gene 10 protein)
ORF7_SPV1R Uncharacterized protein ORF7 (Gene 7 protein)
ORF6_SPV1R Uncharacterized protein ORF6 (Gene 6 protein)
ORF1_SPV1R Uncharacterized protein ORF1 (Gene 1 protein)
ORF5_SPV1R Uncharacterized protein ORF5 (Gene 5 protein)
INTG_SPV1R Putative integrase ORF3 (Gene 3 protein)