Betapolyomavirus

VIRION

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

GENOME

Circular dsDNA about 5 kb in size, associated with cellular histones in a chromatin-like complex. Encodes for 5-9 proteins.
On rare non-specific recombination, the viral genome can be integrated in host chromosome. This inactivates the integrated virus but can give the host cell a replicative advantage sometimes leading to malignant tumours.

GENE EXPRESSION

Transcription is nuclear, in two phases; early (replication), late (virion assembly/exit). 5-9 proteins are expressed from the two pre-MRNA by alternative splicing. All genes are transcribed by host RNA pol II.

REPLICATION

NUCLEAR

  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.

Host-virus interaction

Cell-cycle modulation

The large T antigen binds to host key cell cycle regulators retinoblastoma protein RB1/pRb and TP53 and induces the disassembly of host E2F1 transcription factors from RB1, thus promoting transcriptional activation of E2F1-regulated S-phase genes.

Matching UniProtKB/Swiss-Prot entries

29 entries grouped by strain (browse by keywords)

All proteins are shown (view only 25 complete proteome entries)

6 entries

Simian virus 40 (SV40) reference strain

Select_allDeselect_all
AGNO_SV40 Agnoprotein
LT_SV40 Large T antigen (LT) (LT-AG) (EC 3.6.4.-)
VP2_SV40 Minor capsid protein VP2 (Minor structural protein VP2)
SELP_SV40 SV40 early leader protein (SELP)
ST_SV40 Small t antigen (ST) (ST-AG)
VP1_SV40 Major capsid protein VP1 (Major structural protein VP1)

5 entries

JC polyomavirus (JCPyV) (JCV) reference strain

Select_allDeselect_all
AGNO_POVJC Agnoprotein (Agno)
LT_POVJC Large T antigen (LT) (LT-AG) (EC 3.6.4.-)
ST_POVJC Small t antigen (ST) (ST-AG)
VP2_POVJC Minor capsid protein VP2 (Minor structural protein VP2)
VP1_POVJC Major capsid protein VP1 (Major structural protein VP1)

4 entries

WU polyomavirus (WUPyV) reference strain

Select_allDeselect_all
LT_POVWU Large T antigen (LT) (LT-AG) (EC 3.6.4.-)
ST_POVWU Small t antigen (ST) (ST-AG)
VP2_POVWU Minor capsid protein VP2 (Minor structural protein VP2)
VP1_POVWU Major capsid protein VP1 (Major structural protein VP1)

5 entries

BK polyomavirus (BKPyV) (Human polyomavirus 1)

Select_allDeselect_all
AGNO_POVBK Agnoprotein (Agno)
LT_POVBK Large T antigen (LT) (LT-AG) (EC 3.6.4.-)
ST_POVBK Small t antigen (ST) (ST-AG)
VP2_POVBK Minor capsid protein VP2 (Minor structural protein VP2)
VP1_POVBK Major capsid protein VP1 (Major structural protein VP1)

5 entries

BK polyomavirus (strain AS) (BKPyV)

Select_allDeselect_all
AGNO_POVBA Agnoprotein (Agno)
LT_POVBA Large T antigen (LT) (LT-AG) (EC 3.6.4.-)
ST_POVBA Small t antigen (ST) (ST-AG)
VP2_POVBA Minor capsid protein VP2 (Minor structural protein VP2)
VP1_POVBA Major capsid protein VP1 (Major structural protein VP1)

4 entries

Murine polyomavirus (strain Kilham) (MPyV) (Murine pneumotropic virus)

Select_allDeselect_all
LT_POVMK Large T antigen (LT) (LT-AG) (EC 3.6.4.-)
VP1_POVMK Major capsid protein VP1 (Major structural protein VP1)
ST_POVMK Small t antigen (ST) (ST-AG)
VP2_POVMK Minor capsid protein VP2 (Minor structural protein VP2)