Betaretrovirus

VIRION

Enveloped, spherical to pleomorphic in shape, 80-100 nm in diameter.

GENOME

Monopartite, linear, dimeric, ssRNA(+) genome of about 8-10 kb, with a 5'-cap and a 3’poly-A tail. There are two long terminal repeats (LTRs) of about 600nt long at the 5' and 3' ends. The LTRs contain the U3, R, and U5 regions. There are also a primer binding site (PBS) at the 5’end and a polypurine tract (PPT) at the 3’end.

GENE EXPRESSION

The integrated provirus utilizes the promoter elements in the 5’LTR to drive transcription. This gives rise to the unspliced full length mRNA that will serve as genomic RNA to be packaged into virions or used as a template for translation of gag, gag-pro (1 ribosomal frameshift), and gag-pro-pol (2 ribosomal frameshifts) polyproteins. The spliced mRNAs encode env that is cleaved into SU and TM envelope proteins and sag, a superantigen encoded at the 3’end of the MMTV genome.

REPLICATION

NUCLEAR

  1. Virus attaches to host receptors through the SU glycoprotein. TM glycoprotein mediates fusion with cell membrane.
  2. Internalization and partial uncoating.
  3. ssRNA(+) genome is copied into a linear dsDNA molecule by the reverse transcriptase.
  4. Nuclear entry of the viral dsDNA when the nuclear membrane is disassembled at mitosis.
  5. Viral dsDNA is covalently and randomly integrated into the cell’s genome by the viral integrase (=provirus).
  6. Transcription of provirus by Pol II produces viral spliced and unspliced RNAs.
  7. Nuclear export of the incompletely spliced RNAs.
  8. Translation of unspliced viral RNAs produces Env, Gag and Gag-Pol polyproteins.
  9. Assembly of the virion as intracytoplasmic particles.
  10. Intracytoplasmic particles relocate to the plasma membrane, become enveloped, and are released.
  11. Proteolytic processing of the precursors polyproteins by viral protease and maturation of the virions.

Host-virus interaction

Superantigen

Mouse Mammary Tumour virus expresses a superantigen to evade innate immune response

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Matching UniProtKB/Swiss-Prot entries

36 entries grouped by strain (browse by keywords)

All proteins are shown (view only 26 complete proteome entries)

5 entries

Mouse mammary tumor virus (strain C3H) (MMTV) reference strain

Select_allDeselect_all
ENV_MMTVC Envelope glycoprotein gp70 (Env polyprotein) [Cleaved into: Surface protein (SU) (Glycoprotein 52) ...
GAG_MMTVC Gag polyprotein [Cleaved into: Matrix protein p10; Phosphorylated protein pp21; Protein p3; Protein ...
PRO_MMTVC Gag-Pro polyprotein [Cleaved into: Matrix protein p10; Phosphorylated protein pp21; Protein p3; ...
PR73_MMTVC Protein PR73 (Superantigen) (Sag)
POL_MMTVC Gag-Pro-Pol polyprotein [Cleaved into: Matrix protein p10; Phosphorylated protein pp21; Protein p3; ...

5 entries

Mouse mammary tumor virus (strain BR6) (MMTV)

Select_allDeselect_all
ENV_MMTVB Envelope glycoprotein gp70 (Env polyprotein) [Cleaved into: Surface protein (SU) (Glycoprotein 52) ...
GAG_MMTVB Gag polyprotein [Cleaved into: Matrix protein p10; Phosphorylated protein pp21; Protein p3; Protein ...
PR73_MMTVB Protein PR73
POL_MMTVB Pol polyprotein [Cleaved into: Reverse transcriptase/ribonuclease H (RT) (EC 2.7.7.49) (EC 2.7.7.7) ...
VPRT_MMTVB Protease (EC 3.4.23.-)

5 entries

Sheep pulmonary adenomatosis virus (Jaagsiekte sheep retrovirus) (JSRV)

Select_allDeselect_all
ENV_JSRV Envelope glycoprotein (Env polyprotein) [Cleaved into: Surface protein (SU) (Glycoprotein 52) ...
GAG_JSRV Gag polyprotein [Cleaved into: Matrix protein p10; Core protein p18; p12; Capsid protein p27; ...
POL_JSRV Pol polyprotein [Cleaved into: Reverse transcriptase/ribonuclease H (RT) (EC 2.7.7.49) (EC 2.7.7.7) ...
VPU_JSRV Protein Vpu (ORF-X protein)
VPRT_JSRV Bifunctional protease/dUTPase [Includes: Aspartic protease (EC 3.4.23.-); Deoxyuridine ...

4 entries

Mason-Pfizer monkey virus (MPMV) (Simian Mason-Pfizer virus)

Select_allDeselect_all
ENV_MPMV Envelope glycoprotein (Env polyprotein) [Cleaved into: Surface protein (SU) (Glycoprotein 70) ...
GAG_MPMV Gag polyprotein (Core polyprotein) [Cleaved into: Matrix protein p10; Core phosphoprotein pp24; p12; ...
POL_MPMV Pol polyprotein [Cleaved into: Reverse transcriptase/ribonuclease H (RT) (EC 2.7.7.49) (EC 2.7.7.7) ...
VPRT_MPMV Protease (EC 3.4.23.-)

4 entries

Mouse mammary tumor virus (strain GR) (MMTV)

Select_allDeselect_all
ENV_MMTVG Envelope glycoprotein gp70 (Env polyprotein) [Cleaved into: Surface protein (SU) (Glycoprotein 52) ...
PR7R_MMTVG Protein PR73 3'-endogenous
PR7L_MMTVG Protein PR73 5'-endogenous
PR73_MMTVG Protein PR73

4 entries

Simian retrovirus SRV-1

Select_allDeselect_all
ENV_SRV1 Envelope glycoprotein (Env polyprotein) [Cleaved into: Surface protein (SU) (Glycoprotein 70) ...
GAG_SRV1 Gag polyprotein (Core polyprotein) [Cleaved into: Matrix protein p10; Core phosphoprotein pp18; p12; ...
POL_SRV1 Pol polyprotein [Cleaved into: Reverse transcriptase/ribonuclease H (RT) (EC 2.7.7.49) (EC 2.7.7.7) ...
VPRT_SRV1 Protease (EC 3.4.23.-)

4 entries

Simian retrovirus SRV-2

Select_allDeselect_all
ENV_SRV2 Envelope glycoprotein (Env polyprotein) [Cleaved into: Surface protein (SU) (Glycoprotein 70) ...
GAG_SRV2 Gag polyprotein (Core polyprotein) [Cleaved into: Matrix protein p10; Core phosphoprotein pp18; p12; ...
POL_SRV2 Pol polyprotein [Cleaved into: Reverse transcriptase/ribonuclease H (RT) (EC 2.7.7.49) (EC 2.7.7.7) ...
VPRT_SRV2 Protease (EC 3.4.23.-)

4 entries

Squirrel monkey retrovirus (SMRV-H) (SMRV-HLB)

Select_allDeselect_all
ENV_SMRVH Envelope glycoprotein (Env polyprotein) [Cleaved into: Surface protein (SU) (Glycoprotein 70) ...
GAG_SMRVH Gag polyprotein [Cleaved into: Core protein p19; Core protein p16; Putative nucleocapsid protein ...
POL_SMRVH Pol polyprotein [Cleaved into: Reverse transcriptase/ribonuclease H (RT) (EC 2.7.7.49) (EC 2.7.7.7) ...
VPRT_SMRVH Protease (EC 3.4.23.-)

1 entry

Simian retrovirus SRV-2 (isolate 2R-18B1)

ENV_SRV2R Envelope glycoprotein (Env polyprotein) [Cleaved into: Surface protein (SU) (Glycoprotein 70) ...