Enveloped, spherical, about 120 to 140nm in diameter. The tubular nucleocapsid is bend into an open torus hence the name “torovirus”.


Monopartite, linear ssRNA(+) genome of 28kb in size. Capped, and polyadenylated.


The virion RNA is infectious and serves as both the genome and viral messenger RNA. Genomic RNA encodes for ORF1a, as for ORF1b, it is translated by ribosomal frameshifting. Resulting proteins pp1a and pp1ab are processed into the viral polymerase (RdRp) and other non-structural proteins involved in RNA synthesis. Structural proteins are expressed as subgenomic RNAs. Each RNA (genomic and subgenomic) is translated to yield only the protein encoded by the 5’-most ORF.
A putative 30K protein overlapping ORF1a might be expressed from an alternative CUG codon .



  1. Attachement of the viral S protein (maybe also HE if present) to host receptors mediates endocytosis of the virus into the host cell.
  2. Synthesis and proteolytic cleavage of the replicase polyprotein.
  3. Fusion of virus membrane with the endosomal membrane (probably mediated by E2), ssRNA(+) genome is released into the cytoplasm.
  4. Synthesis and proteolytic cleavage of the replicase polyprotein.
  5. Replication occurs in viral factories. A dsRNA genome is synthesized from the genomic ssRNA(+).
  6. The dsRNA genome is transcribed/replicated thereby providing viral mRNAs/new ssRNA(+) genomes.
  7. Synthesis of structural proteins encoded by subgenomic mRNAs.
  8. Assembly and budding at membranes of the endoplasmic reticulum (ER), the intermediate compartments, and/or the Golgi complex.
  9. Release of new virions by exocytosis.

Host-virus interaction

Apoptosis modulation

Equine torovirus Berne virus induces apoptosis in infected cells at late times postinfection via host caspases activation .

Matching UniProtKB/Swiss-Prot entries

15 entries grouped by strain (browse by keywords)

All proteins are shown (view only 12 complete proteome entries)

6 entries

Berne virus (BEV) reference strain

Select_all Deselect_all  
HEMA_BEVTruncated non-functional hemagglutinin-esterase homolog
NCAP_BEVNucleoprotein (Nucleocapsid protein) (NC) (Protein N)
R1AB_BEVReplicase polyprotein 1ab (pp1ab) (ORF1ab polyprotein)
R1A_BEVReplicase polyprotein 1a (pp1a) (ORF1a polyprotein)
SPIKE_BEVSpike glycoprotein (S glycoprotein) (E2) (Peplomer protein)
VME1_BEVMembrane protein (M protein) (E1 glycoprotein) (Matrix glycoprotein) (Membrane ...

6 entries

Breda virus 1 (BRV-1) reference strain

Select_all Deselect_all  
HEMA_BRV1Hemagglutinin-esterase (HE protein) (EC (E3 glycoprotein)
NCAP_BRV1Nucleoprotein (Nucleocapsid protein) (NC) (Protein N)
R1AB_BRV1Replicase polyprotein 1ab (pp1ab) (ORF1ab polyprotein)
R1A_BRV1Replicase polyprotein 1a (pp1a) (ORF1a polyprotein)
SPIKE_BRV1Spike glycoprotein (S glycoprotein) (E2) (Peplomer protein)
VME1_BRV1Membrane protein (M protein) (E1 glycoprotein) (Matrix glycoprotein) (Membrane ...

1 entry

Breda virus 2 (BRV-2)

HEMA_BRV2Hemagglutinin-esterase (HE protein) (EC (E3 glycoprotein)

1 entry

Human torovirus (HuTV)

HEMA_HUTVHemagglutinin-esterase (HE protein) (EC (E3 glycoprotein)

1 entry

Porcine torovirus (strain P10) (PoTV)

HEMA_PTV10Hemagglutinin-esterase (HE protein) (EC (E3 glycoprotein)