Gammapolyomavirus (taxid:1891716)



Non-enveloped capsid with a T=7d icosahedral symmetry, about 50 nm in diameter.



Circular dsDNA about 5 kb in size, associated with cellular histones in a chromatin-like complex. Encodes for 9 proteins.


Transcription is nuclear, in two phases; early (replication), late (virion assembly/exit). Proteins are expressed from the two pre-MRNA by alternative splicing. All genes are transcribed by host RNA pol II.



  1. Attachement of the viral proteins to host receptors triggers lipid-mediated endocytosis of the virus into the host cell.
  2. Virion transits through endoplasmic reticulum where host protein disulfide isomerases rearrange its capsid structure
  3. Export of misfolded virion to the cytoplasm possibly through host ERAD pathway
  4. Loss of VP1 in the low-calcium conditions of the cytosol
  5. Import of genomic DNA into host nucleus.
  6. Transcription of early genes (LT and sT genes)
  7. Replication of the DNA genome in the nucleus.
  8. Transcription of late genes encoding for structural proteins (VP1, VP2 and VP3).
  9. Assembly of new virions in nuclear viral factories.
  10. Virions are released by lysis of the cell.

Matching UniProtKB/Swiss-Prot entries

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6 entries grouped by strain

6 entries

Budgerigar fledgling disease virus (BFPyV) (Aves polyomavirus 1) reference strain

VP2_BFPYV Minor capsid protein VP2 (Minor structural protein VP2)
VP1_BFPYV Major capsid protein VP1 (Major structural protein VP1)
LT_BFPYV Large T antigen (LT) (LT-AG) (EC 3.6.4.-)
AGNO2_BFPYV Avian agnoprotein 2b (Agno-2b)
ST_BFPYV Small t antigen (ST) (ST-AG)
AGNO1_BFPYV Avian agnoprotein 1a (Agno-1a)