Orthoreovirus

VIRION

Non enveloped, icosahedral virion with a double capsid structure, about 80 nm in diameter. Pentameric turrets sit on the outside of the innermost capsid. The outer capsid has a T=13 icosahedral symmetry, the inner capsid a T=2* icosahedral symmetry.
Virion maturation schemes

GENOME

Segmented dsRNA linear genome. Contains 10 segments: L1, L2, L3, M1, M2, M3, S1, S2, S3, S4, coding for 12-13 proteins. Segments size range from 1,189 to 3,916nt (MRV-3De). Genome total size is 23.5 Kb (MRV-3De). MuNSC and S.1s are produced by leaky scanning of mRNA M3 and S1 respectively.

GENE EXPRESSION

The dsRNA genome is never completely uncoated, to prevent activation of antiviral state by the cell in response to dsRNA. The viral polymerase lambda3 synthesizes a capped and non-polyadenylated monocistronic mRNA from each dsRNA segment. These capped mRNAs are translocated to the cell cytoplasm where they are translated.

REPLICATION

CYTOPLASMIC

  1. Attachement to host receptors mediates clathrin-mediated endocytosis of virus into host cell.
  2. Particles are partially uncoated in endolysosomes, but not entirely, and penetrate in the cytoplasm.
  3. Early transcription of the dsRNA genome by viral polymerase occurs inside this sub-viral particle (naked core), so that dsRNA is never exposed to the cytoplasm.
  4. Full-length plus-strand transcripts from each of the dsRNA segments are synthesized. These plus-strand transcripts are used as templates for translation.
  5. Viral proteins and genomic RNAs aggregates in cytoplasmic viral factories.
  6. (+)RNAs are encapsidated in a sub-viral particle, in which they are transcribed to give RNA (-) molecules with which they become base-paired to produce dsRNA genomes.
  7. The capsid is assembled on the sub-viral particle.
  8. Mature virions are released presumably following cell death and associated breakdown of host plasma membrane.

Host-virus interaction

Apoptosis modulation

Mammalian reovirus mediates host cell apoptosis through the activation of death receptors, including TRAIL, TNFR and Fas . Activation of these death receptors induces the activation downstream caspases (caspase-3).

Avian orthoreovirus induces host cell apoptosis probably through upregulation of p53 (activation of DNA-damage signalling) by viral sigmaC protein .

Autophagy modulation

Avian orthoreovirus also seems to induces autophagy .

Innate immune response inhibition

Mammalian orthoreoreovirus σ3 protein binds to dsRNA and inhibits the PRK-mediated antiviral response of the host cell .
Mammalian orthoreovirus &mu2; protein from strain Lang (T1L) inhibits IFN-beta-induced reporter gene expression .

Avian orthoreovirus σA protein binds to dsRNA and inhibits the PRK-mediated antiviral response of the host cell .

Cell-cycle modulation

Human and avian reovirus induce G2/M cell cycle arrest .

Matching UniProtKB/Swiss-Prot entries

34 entries grouped by strain (browse by keywords)

All proteins are shown (view only 32 complete proteome entries)

11 entries

Reovirus type 1 (strain Lang) (T1L) (Mammalian orthoreovirus 1) reference strain

Select_allDeselect_all
LMBD1_REOVL Inner capsid protein lambda-1 (Lambda1) (EC 3.6.4.13) (ATP-dependent DNA helicase lambda-1) ...
LMBD2_REOVL Outer capsid protein lambda-2 (Lambda2) (Lambda2(Cap)) [Includes: mRNA guanylyltransferase (EC ...
MUNS_REOVL Protein mu-NS (MuNS)
MU1_REOVL Outer capsid protein mu-1 (Mu1) [Cleaved into: Outer capsid protein mu-1N; Outer capsid protein ...
MU2_REOVL Microtubule-associated protein mu-2 (Mu2)
RDRP_REOVL RNA-directed RNA polymerase lambda-3 (Lambda3) (EC 2.7.7.48) (Lambda3(Pol))
SIGM2_REOVL Inner capsid protein sigma-2 (Sigma2)
SIGNS_REOVL Protein sigma-NS (SigmaNS)
SIGM1_REOVL Outer capsid protein sigma-1 (Sigma1) (Cell attachment protein) (Hemagglutinin)
SIGM3_REOVL Outer capsid protein sigma-3 (Sigma3)
SIG1S_REOVL Protein sigma-1-small (Sigma1s) (Sigma-s) (Sigma1NS) (Sigma1bNS) (p14)

11 entries

Reovirus type 2 (strain D5/Jones) (T2J) (Mammalian orthoreovirus 2)

Select_allDeselect_all
LMBD1_REOVJ Inner capsid protein lambda-1 (Lambda1) (EC 3.6.4.13) (ATP-dependent DNA helicase lambda-1) ...
LMBD2_REOVJ Outer capsid protein lambda-2 (Lambda2) (Lambda2(Cap)) [Includes: mRNA guanylyltransferase (EC ...
MU2_REOVJ Microtubule-associated protein mu-2 (Mu2)
MUNS_REOVJ Protein mu-NS (MuNS)
MU1_REOVJ Outer capsid protein mu-1 (Mu1) [Cleaved into: Outer capsid protein mu-1N; Outer capsid protein ...
RDRP_REOVJ RNA-directed RNA polymerase lambda-3 (Lambda3) (EC 2.7.7.48) (Lambda3(Pol))
SIGM2_REOVJ Inner capsid protein sigma-2 (Sigma2)
SIGM3_REOVJ Outer capsid protein sigma-3 (Sigma3)
SIG1S_REOVJ Protein sigma-1-small (Sigma1s) (Sigma-s) (Sigma1NS) (Sigma1bNS) (p14)
SIGM1_REOVJ Outer capsid protein sigma-1 (Sigma1) (Cell attachment protein) (Hemagglutinin)
SIGNS_REOVJ Protein sigma-NS (SigmaNS)

11 entries

Reovirus type 3 (strain Dearing) (T3D) (Mammalian orthoreovirus 3)

Select_allDeselect_all
LMBD1_REOVD Inner capsid protein lambda-1 (Lambda1) (EC 3.6.4.13) (ATP-dependent DNA helicase lambda-1) ...
LMBD2_REOVD Outer capsid protein lambda-2 (Lambda2) (Lambda2(Cap)) [Includes: mRNA guanylyltransferase (EC ...
MU1_REOVD Outer capsid protein mu-1 (Mu1) [Cleaved into: Outer capsid protein mu-1N; Outer capsid protein ...
MU2_REOVD Microtubule-associated protein mu-2 (Mu2)
MUNS_REOVD Protein mu-NS (MuNS)
RDRP_REOVD RNA-directed RNA polymerase lambda-3 (Lambda3) (EC 2.7.7.48) (Lambda3(Pol))
SIG1S_REOVD Protein sigma-1-small (Sigma1s) (Sigma-s) (Sigma1NS) (Sigma1bNS) (p14)
SIGM1_REOVD Outer capsid protein sigma-1 (Sigma1) (Cell attachment protein) (Hemagglutinin)
SIGNS_REOVD Protein sigma-NS (SigmaNS)
SIGM2_REOVD Inner capsid protein sigma-2 (Sigma2)
SIGM3_REOVD Outer capsid protein sigma-3 (Sigma3)

1 entry

Avian reovirus (strain S1133) (ARV)

SIGC_ARVS1 Sigma-C capsid protein (Sigma-3 protein)