Arteriviridae

VIRION

Enveloped, spherical, about 45-60 nm in diameter. The virion is comprised of an isometric core of 20-30 nm surrounded by a lipid-containing envelope. The RNA genome associates with the N protein to form the nucleocapsid.

GENOME

Monopartite, linear, ssRNA(+) genome of 12-16kb in size, capped, and polyadenylated. The leader RNA (65-89 bp) at the 5' end of the genome is also present at the end of each subgenomic RNAs.

GENE EXPRESSION

The virion RNA is infectious and serves as both genome and viral messenger RNA. ORF1b is translated by a ribosomal frameshifting. Polyproteins 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. The mRNA2 is bicistronic. PRRSV, LDV and SHFV also express a truncated polyprotein 1aTF due to a ribosomal frameshifting in the nsp2 gene.
The 3' proximal region of SHFV contains in addition a large insertion that may encode three additional glycoproteins. Protein GP2 and 5a are produced by leaky scanning from the E and gp5 subgenomic mRNA respectively.

REPLICATION

CYTOPLASMIC

  1. Attachement to host receptors mediates clathrin-mediated endocytosis of the virus into the host cell.
  2. Fusion of virus membrane with the endosomal membrane. ssRNA(+) genome is released into the cytoplasm.
  3. Synthesis and proteolysis of replicase polyproteins.
  4. Replication occurs in viral factories. A dsRNA genome is synthesized from the genomic ssRNA(+).
  5. The dsRNA genome is transcribed/replicated thereby providing viral mRNAs/new ssRNA(+) genomes.
  6. Synthesis of structural proteins encoded by subgenomic mRNAs.
  7. assembly and ESCRT-independent budding at the membranes of endoplasmic reticulum (ER), intermediate compartments, and/or Golgi complex.
  8. Release of new virions by exocytosis.

Host-virus interaction

Apoptosis modulation

The equine arteritis virus and PRRSV induce apoptosis via host caspases activation (caspase-8 and mitochondria-dependent caspase-9)

Autophagy modulation

PRRSV induces autophagy to promote virus replication .

Innate immune response inhibition

PRRSV clearly inhibits the type-I IFN response and down-regulates TLR3, TLR7, and TLR8 expression.
At least three non-structural proteins (Nsp1, Nsp2, and Nsp11) play roles in the IFN suppression and NF-κB pathways :

Nsp1α subunit inhibits the IκB phosphorylation in the cytoplasm and therefore the activation of NF-κB.

Nsp1β inhibits phosphorylation of STAT1 and nuclear translocation of ISGF3 complex (composed of STAT1, STAT2 and IRF9). Nsp1β prevents IRF3 activation, thereby interfering with the RIG-I signaling pathway .

Nsp2 inhibits IFN production by blocking the ubiquitinylation of phosphorylated IκB and phosphorylation of IRF3 through the OTU domain. Nsp2 has the potential to deconjugate ISGylation.

Nsp11 suppresses IFN-β production through degradation of IPS-1 mRNA. For the second wave of IFN signaling, PRRSV Nsp1β blocks the phosphorylation of STATs and inhibits the nuclear translocation of ISGF3 complex (composed of STAT1, STAT2 and IRF9).

Matching UniProtKB/Swiss-Prot entries

39 entries grouped by protein (browse by keywords)

All proteins are shown (view only 30 complete proteome entries)

1 entry

Truncated polyprotein 1aTF

1ATF_PRRSS
Porcine reproductive and respiratory syndrome virus (isolate Pig/United States/SD 01-08/2001) (PRRSV)

3 entries

Envelope small membrane protein (Protein E) (Glycoprotein 2b) (Protein GP2b) (Gs)

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E_EAVBU
Equine arteritis virus (strain Bucyrus) (EAV) reference strain

Envelope small membrane protein (Protein E) (Glycoprotein 2a) (Protein GP2a)

E_PRRSL
Porcine reproductive and respiratory syndrome virus (strain Lelystad) (PRRSV) reference strain
E_PRRSS
Porcine reproductive and respiratory syndrome virus (isolate Pig/United States/SD 01-08/2001) (PRRSV)

2 entries

Glycoprotein 2a (Protein GP2a) (GP2)

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GP2A_PRRSL
Porcine reproductive and respiratory syndrome virus (strain Lelystad) (PRRSV) reference strain
GP2A_PRRSS
Porcine reproductive and respiratory syndrome virus (isolate Pig/United States/SD 01-08/2001) (PRRSV)

1 entry

Glycoprotein 2b (Protein GP2b) (GP(S))

GP2B_EAVBU
Equine arteritis virus (strain Bucyrus) (EAV) reference strain

3 entries

Glycoprotein 3 (Protein GP3)

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GP3_EAVBU
Equine arteritis virus (strain Bucyrus) (EAV) reference strain
GP3_PRRSL
Porcine reproductive and respiratory syndrome virus (strain Lelystad) (PRRSV) reference strain
GP3_PRRSS
Porcine reproductive and respiratory syndrome virus (isolate Pig/United States/SD 01-08/2001) (PRRSV)

3 entries

Glycoprotein 4 (Protein GP4)

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GP4_EAVBU
Equine arteritis virus (strain Bucyrus) (EAV) reference strain
GP4_PRRSL
Porcine reproductive and respiratory syndrome virus (strain Lelystad) (PRRSV) reference strain
GP4_PRRSS
Porcine reproductive and respiratory syndrome virus (isolate Pig/United States/SD 01-08/2001) (PRRSV)

3 entries

Glycoprotein 5 (Protein GP5) (G(L))

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GP5_EAVBU
Equine arteritis virus (strain Bucyrus) (EAV) reference strain
GP5_PRRSL
Porcine reproductive and respiratory syndrome virus (strain Lelystad) (PRRSV) reference strain
GP5_PRRSS
Porcine reproductive and respiratory syndrome virus (isolate Pig/United States/SD 01-08/2001) (PRRSV)

3 entries

Membrane protein (Protein M)

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M_EAVBU
Equine arteritis virus (strain Bucyrus) (EAV) reference strain
M_PRRSL
Porcine reproductive and respiratory syndrome virus (strain Lelystad) (PRRSV) reference strain
M_PRRSS
Porcine reproductive and respiratory syndrome virus (isolate Pig/United States/SD 01-08/2001) (PRRSV)

5 entries

Nucleoprotein (Nucleocapsid protein) (Protein N)

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NCAP_EAVBU
Equine arteritis virus (strain Bucyrus) (EAV) reference strain
NCAP_PRRSL
Porcine reproductive and respiratory syndrome virus (strain Lelystad) (PRRSV) reference strain
NCAP_LDV
Lactate dehydrogenase-elevating virus (LDV)
NCAP_LDVC
Lactate dehydrogenase elevating virus (strain C) (LDV)
NCAP_PRRSS
Porcine reproductive and respiratory syndrome virus (isolate Pig/United States/SD 01-08/2001) (PRRSV)

3 entries

Structural protein ORF5a

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ORF5A_EAVBU
Equine arteritis virus (strain Bucyrus) (EAV) reference strain

Protein ORF5a

ORF5A_PRRSL
Porcine reproductive and respiratory syndrome virus (strain Lelystad) (PRRSV) reference strain
ORF5A_PRRSR
Porcine reproductive and respiratory syndrome virus (strain VR-2332) (PRRSV)

9 entries

Replicase polyprotein 1ab (ORF1ab polyprotein)

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RPOA_EAVBU
Equine arteritis virus (strain Bucyrus) (EAV) reference strain
RPOA_PRRSB
Porcine reproductive and respiratory syndrome virus (strain HB-1) (PRRSV) reference strain
RPOA_PRRSL
Porcine reproductive and respiratory syndrome virus (strain Lelystad) (PRRSV) reference strain
RPOA_SHFV
Simian hemorrhagic fever virus (SHFV) reference strain
RPOA_LDVC
Lactate dehydrogenase elevating virus (strain C) (LDV)
RPOA_LDVP
Lactate dehydrogenase elevating virus (strain Plagemann) (LDV)
RPOA_PRRS1
Porcine reproductive and respiratory syndrome virus (strain 16244B) (PRRSV)
RPOA_PRRSR
Porcine reproductive and respiratory syndrome virus (strain VR-2332) (PRRSV)
RPOA_PRRSS
Porcine reproductive and respiratory syndrome virus (isolate Pig/United States/SD 01-08/2001) (PRRSV)

1 entry

Replicase polyprotein 1TF (ORF1ab polyprotein)

RPOTF_PRRSL
Porcine reproductive and respiratory syndrome virus (strain Lelystad) (PRRSV) reference strain

2 entries

Protein X (Envelope protein) (VpX)

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VPX_LDV
Lactate dehydrogenase-elevating virus (LDV)
VPX_LDVC
Lactate dehydrogenase elevating virus (strain C) (LDV)