Non-enveloped, round, T=1 icosahedral symmetry, about 20 nm in diameter. The capsid consists of 12 pentagonal trumpet-shaped pentomers.


Monopartite, circular, ssDNA genome of about 1.8 to 3.8 kb.
The genome is replicated through double-stranded intermediates. The replication (Rep) protein initiates rolling circle replication.


One or two mRNAs encode for the Rep, capsid, and possibly others proteins. Some mRNA can undergo alternative splicing.



  1. Virus penetrates into the host cell.
  2. Uncoating, the viral ssDNA genome penetrates into the nucleus.
  3. Viral ssDNA is converted into dsDNA with the participation of cellular factors. dsDNA transcription gives rise to viral mRNAs.
  4. Viral mRNAs are translated to produce viral proteins.
  5. Replication may be mediated by a Rep protein, and would occur by rolling circle replication producing ssDNA genomes.
  6. These newly synthesized ssDNA can either
    a) be converted to dsDNA and serve as a template for transcription/replication
    b) be encapsidated by capsid protein and form virions released by cell lysis.

Host-virus interaction

Autophagy modulation

Cap protein of PCV2 induces activation of host autophagy in order to enhance its own replication .

Apoptosis modulation

PCV2 ORF3-encoded protein induces apoptosis by activating caspase-8 and caspase-3 pathways . This protein may be a candidate for PML bodies inhibition which is essential for nuclear virus replication in mammals.

Matching UniProtKB/Swiss-Prot entries

40 entries grouped by strain (browse by keywords)

All proteins are shown (view only 39 complete proteome entries)

7 entries

Beak and feather disease virus (BFDV) reference strain

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CAPSD_BFDVCapsid protein
ORF3_BFDVUncharacterized protein ORF3
ORF4_BFDVUncharacterized protein ORF4
ORF5_BFDVUncharacterized protein ORF5
ORF6_BFDVUncharacterized protein ORF6
ORF7_BFDVUncharacterized protein ORF7
REP_BFDVReplication-associated protein (EC 2.7.7.-) (EC 3.1.21.-) (EC ...

3 entries

Chicken anemia virus (isolate Germany Cuxhaven-1) (CAV) reference strain

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CAPSD_CAVC1Capsid protein (CA1) (Coat protein)
VP2_CAVC1Dual specificity protein phosphatase VP2 (EC (EC

2 entries

Canary circovirus (CaCV) reference strain

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CAPSD_CACVProbable capsid protein
REP_CACVReplication-associated protein (EC 2.7.7.-) (EC 3.1.21.-) (EC ...

2 entries

Porcine circovirus 1 (isolate China) (PCV1) reference strain

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CAPSD_PCV1CCapsid protein
REP_PCV1CReplication-associated protein (EC 2.7.7.-) (EC 3.1.21.-) (EC ...

5 entries

Pigeon circovirus (PiCV) (Columbid circovirus)

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CAPSD_PICVProbable capsid protein
ORFC2_PICVUncharacterized protein ORFC2
ORFC3_PICVUncharacterized protein ORFC3
ORFC4_PICVUncharacterized protein ORFC4
REP_PICVReplication-associated protein (EC 2.7.7.-) (EC 3.1.21.-) (EC ...

4 entries

Goose circovirus (GoCV)

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CAPSD_GOCVProbable capsid protein
ORFC2_GOCVUncharacterized protein ORFC2
ORFV2_GOCVUncharacterized protein ORFV2
REP_GOCVReplication-associated protein (EC 2.7.7.-) (EC 3.1.21.-) (EC ...

4 entries

Porcine circovirus 2 (PCV2)

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CAPSD_PCV2Capsid protein
NS0_PCV2Protein NS0
ORF3_PCV2Protein ORF3
REP_PCV2Replication-associated protein (EC 2.7.7.-) (EC 3.1.21.-) (EC ...

3 entries

Chicken anemia virus (isolate Australia/CAU269-7/2000) (CAV)

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CAPSD_CAVCACapsid protein (CA1) (Coat protein)
VP2_CAVCADual specificity protein phosphatase VP2 (EC (EC

3 entries

Chicken anemia virus (isolate Japan 82-2) (CAV)

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CAPSD_CAV82Capsid protein (CA1) (Coat protein)
VP2_CAV82Dual specificity protein phosphatase VP2 (EC (EC

3 entries

Chicken anemia virus (isolate USA 26p4) (CAV)

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CAPSD_CAV26Capsid protein (CA1) (Coat protein)
VP2_CAV26Dual specificity protein phosphatase VP2 (EC (EC

3 entries

Chicken anemia virus (isolate USA CIA-1) (CAV)

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CAPSD_CAVCICapsid protein (CA1) (Coat protein)
VP2_CAVCIDual specificity protein phosphatase VP2 (EC (EC

1 entry

Chicken anemia virus (isolate Australia) (CAV)

CAPSD_CAVAUCapsid protein (CA1) (Coat protein)