Enterovirus

NB. Rhinoviruses are merged into enterovirus genus

VIRION

Non-enveloped, spherical, about 30 nm in diameter, T=pseudo3 icosahedral capsid surrounding the naked RNA genome. The capsid consists of a densely-packed icosahedral arrangement of 60 protomers, each consisting of 4 polypeptides, VP1, VP2, VP3 and VP4. VP4 is located on the internal side of the capsid.


Enterovirus:
Rhinovirus :

GENOME

Monopartite, linear ssRNA(+) genome of 7.2-8.5 kb, polyadenylated, composed of a single ORF encoding a polyprotein. Viral genomic RNA has a viral protein (VPg) at its 5’ end instead of a methylated nucleotide cap structure. The long UTR at the 5’ end contains a type I internal ribosome entry site. The P1 region encodes the structural polypeptides. The P2 and P3 regions encode the nonstructural proteins associated with replication.

GENE EXPRESSION

The virion RNA is infectious and serves as both the genome and viral messenger RNA. The IRES allows direct translation of the polyprotein. The polyprotein is initially processed by the viral proteases into three precursor proteins, P1, P2, and P3. Precursor P1 is then proteolytically cleaved to yield the structural proteins. Precursors P2 and P3 are processed into replicase, VPg, and a number of proteins that modify the host cell, ultimately leading to cell lysis.

REPLICATION

poliovirus replication cycle

CYTOPLASMIC

  1. Attachement of the virus to host receptors mediates endocytosis of the virus into the host cell.
  2. The capsid undergoes a conformational change and releases VP4 that opens a pore in the host endosomal membrane and the viral genomic RNA penetrates into the host cell cytoplasm (the empty capsid remains intact).
  3. VPg is removed from the viral RNA, which is then translated into a processed polyprotein.
  4. Shutoff of cellular cap-dependent translation through the cleavage of translation initiation factors by viral protease.
  5. Replication occurs in viral factories made of membrane vesicles derived from the ER. A dsRNA genome is synthesized from the genomic ssRNA(+).
  6. The dsRNA genome is transcribed/replicated thereby providing viral mRNAs/new ssRNA(+) genomes.
  7. New genomic RNA is believed to be packaged into preassembled procapsids.
  8. Cell lysis and virus release.
  9. Maturation of provirions by an unknown host protease.

Host-virus interaction

Apoptosis modulation

Picornaviruses modulate host apoptosis .

Poliovirus infection activates the apoptotic pathway, involving mitochondrial damage, cytochrome c efflux, and consecutive activation of caspases (caspase-3 caspase and -9) , whereas antiapoptotic activity has been attributed to cardiovirus leader protein .

Modulation of apoptosis depends on the host cell-type and on the time the infection because of the presence of viral pro- and anti-apoptotic factors respectively at the beginning and at the end of the infectious cycle .

Autophagy modulation

Picornaviruses subvert the cell autophagic pathway to facilitates viral infection :

- Human rhinovirus 2 activates the autophagic pathway
- Coxsackievirus and poliovirus infection induces autophagy-like vesicles

Innate immune response inhibition

Picornaviruses inhibit the host IFN-mediated response by inactivating either MDA-5, RIG-I, MAVS or IRF-3:
- Coxsackievirus B3 cleaves and inhibits MAVS
- Enteroviruses cleave and inhibit RIG-I
- Poliovirus cleaves and inhibits MDA-5

Picornaviruses inhibit Toll-like receptor 3 mediated antiviral response as well:

- Coxsackievirus B 3C and enterovirus 71 proteases 3C cleave TRIF .

Host gene expression shutoff by virus

Enteroviruses inhibit host translation by cleaving PABP (coxsackievirus and poliovirus) , eIF5B and activating 4E-BP1 .

Poliovirus also inhibits host transcription by cleaving the TATA-binding protein .

HRV14, HRV16 and poliovirus inhibit host mRNA export as well .

Matching UniProtKB/Swiss-Prot entries

41 entries grouped by protein (browse by keywords)

Genome polyprotein

Select_all Deselect_all  
POLG_HRV8AHuman rhinovirus A serotype 89 (strain 41467-Gallo) (HRV-89) reference strain
POLG_POL1MPoliovirus type 1 (strain Mahoney) reference strain
POLG_BOVEVBovine enterovirus (strain VG-5-27) (BEV)
POLG_CX16GCoxsackievirus A16 (strain G-10)
POLG_CX16TCoxsackievirus A16 (strain Tainan/5079/98)
POLG_CXA21Coxsackievirus A21 (strain Coe)
POLG_CXA24Coxsackievirus A24 (strain EH24/70)
POLG_CXA9Coxsackievirus A9 (strain Griggs)
POLG_CXB1JCoxsackievirus B1 (strain Japan)
POLG_CXB2OCoxsackievirus B2 (strain Ohio-1)
POLG_CXB3NCoxsackievirus B3 (strain Nancy)
POLG_CXB3WCoxsackievirus B3 (strain Woodruff)
POLG_CXB4ECoxsackievirus B4 (strain E2)
POLG_CXB4JCoxsackievirus B4 (strain JVB / Benschoten / New York/51)
POLG_CXB5PCoxsackievirus B5 (strain Peterborough / 1954/UK/85)
POLG_CXB6SCoxsackievirus B6 (strain Schmitt)
POLG_EC01FEchovirus 1 (strain Human/Egypt/Farouk/1951) (E-1)
POLG_EC11GEchovirus 11 (strain Gregory)
POLG_EC12TEchovirus 12 (strain Travis)
POLG_EC30BEchovirus 30 (strain Bastianni)
POLG_EC05NEchovirus 5 (strain Noyce)
POLG_EC06CEchovirus 6 (strain Charles)
POLG_EC09BEchovirus 9 (strain Barty)
POLG_EC09HEchovirus 9 (strain Hill)
POLG_HE701Human enterovirus 70 (strain J670/71) (EV 70)
POLG_HE71MHuman enterovirus 71 (strain 7423/MS/87) (Ev 71)
POLG_HE71BHuman enterovirus 71 (strain BrCr) (Ev 71)
POLG_HRV14Human rhinovirus 14 (HRV-14)
POLG_HRV16Human rhinovirus 16 (HRV-16)
POLG_HRV1AHuman rhinovirus 1A (HRV-1A)
POLG_HRV1BHuman rhinovirus 1B (HRV-1B)
POLG_HRV2Human rhinovirus 2 (HRV-2)
POLG_HRV3Human rhinovirus 3 (HRV-3)
POLG_POL1SPoliovirus type 1 (strain Sabin)
POLG_POL2LPoliovirus type 2 (strain Lansing)
POLG_POL2WPoliovirus type 2 (strain W-2)
POLG_POL32Poliovirus type 3 (strain 23127)
POLG_POL3LPoliovirus type 3 (strains P3/Leon/37 and P3/Leon 12A[1]B)
POLG_PEV9UPorcine enterovirus 9 (strain UKG/410/73)
POLG_SVDVHSwine vesicular disease virus (strain H/3 '76) (SVDV)
POLG_SVDVUSwine vesicular disease virus (strain UKG/27/72) (SVDV)