Picornaviridae

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.

GENOME

Monopartite, linear ssRNA(+) genome of 7.1-8.9 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 an internal ribosome entry site. The P1 region encodes the structural polypeptides. The P2 and P3 regions encode the nonstructural proteins associated with replication. The shorter 3’ UTR is important in (-)strand synthesis. L is an additional N-terminal leader protein present in some genera that can either be a papain-like cysteine proteinases (genera aphthovirus, erbovirus) or have another function (genera kobuvirus, cardiovirus, teschovirus, sapelovirus, senecavirus).

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 protease(s) into various precursor and mature proteins to yield the structural proteins, replicase, VPg, and a number of proteins that modify the host cell, ultimately leading to cell lysis.

REPLICATION

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.
  3. VPg is removed from the viral RNA, which is then translated into a processed polyprotein.
  4. In entero-, rhino-, and aphthoviruses, 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 and EMCV activates the autophagic pathway
- Foot-and-mouth disease virus utilizes 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:
- HAV cleaves and inhibits MAVS
- Coxsackievirus B3 cleaves and inhibits MAVS
- Enteroviruses and cardiviruses cleave and inhibit RIG-I
-Poliovirus cleaves and inhibits MDA-5
- Mengovirus and foot-and-mouth disease virus leader proteins inhibit IRF-3 .

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

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

Host gene expression shutoff by virus

Picornaviruses inhibit host translation by cleaving various translation factors such as PABP (FMDV, poliovirus and coxsackievirus) , eIF3a, eIF3b (FMDV) , eIF5B and activating 4E-BP1 .

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

Some enteroviruses or cardioviruses inhibit host mRNA export as well.

Matching UniProtKB/Swiss-Prot entries

78 entries grouped by strain (browse by keywords)

2 entries

Encephalomyocarditis virus (strain Rueckert) (EMCV) reference strain

Select_all Deselect_all  
ALT2B_EMCVRProtein 2B*
POLG_EMCVRGenome polyprotein

1 entry

Avian encephalomyelitis virus (strain Calnek vaccine) (AEV) reference strain


POLG_AEVCAGenome polyprotein

1 entry

Human hepatitis A virus genotype IB (isolate HM175) (HHAV) (Human hepatitis A virus (isolate Human/Australia/HM175/1976)) reference strain


POLG_HAVHMGenome polyprotein

1 entry

Human parechovirus 2 (strain Williamson) (HPeV-2) (Echovirus 23) reference strain


POLG_HPE2WGenome polyprotein

1 entry

Human rhinovirus A serotype 89 (strain 41467-Gallo) (HRV-89) reference strain


POLG_HRV8AGenome polyprotein

1 entry

Poliovirus type 1 (strain Mahoney) reference strain

2 entries

Encephalomyocarditis virus

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ALT2B_EMCVProtein 2B*
POLG_EMCVGenome polyprotein

2 entries

Mengo encephalomyocarditis virus

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ALT2B_ENMGOProtein 2B*
POLG_ENMGOGenome polyprotein

2 entries

Theiler's murine encephalomyelitis virus (strain DA) (TMEV)

Select_all Deselect_all  
POLG_TMEVDGenome polyprotein
SMALL_TMEVDProtein L*

1 entry

Avian encephalomyelitis virus (strain L2Z) (AEV)


POLG_AEVL2Genome polyprotein

1 entry

Avian encephalomyelitis virus (strain Van Reokel) (AEV)


POLG_AEVVRGenome polyprotein

1 entry

Bovine enterovirus (strain VG-5-27) (BEV)


POLG_BOVEVGenome polyprotein

1 entry

Coxsackievirus A16 (strain G-10)


POLG_CX16GGenome polyprotein

1 entry

Coxsackievirus A16 (strain Tainan/5079/98)


POLG_CX16TGenome polyprotein

1 entry

Coxsackievirus A21 (strain Coe)


POLG_CXA21Genome polyprotein

1 entry

Coxsackievirus A24 (strain EH24/70)


POLG_CXA24Genome polyprotein

1 entry

Coxsackievirus A9 (strain Griggs)


POLG_CXA9Genome polyprotein

1 entry

Coxsackievirus B1 (strain Japan)


POLG_CXB1JGenome polyprotein

1 entry

Coxsackievirus B2 (strain Ohio-1)


POLG_CXB2OGenome polyprotein

1 entry

Coxsackievirus B3 (strain Nancy)

1 entry

Coxsackievirus B3 (strain Woodruff)


POLG_CXB3WGenome polyprotein

1 entry

Coxsackievirus B4 (strain E2)


POLG_CXB4EGenome polyprotein

1 entry

Coxsackievirus B4 (strain JVB / Benschoten / New York/51)


POLG_CXB4JGenome polyprotein

1 entry

Coxsackievirus B5 (strain Peterborough / 1954/UK/85)


POLG_CXB5PGenome polyprotein

1 entry

Coxsackievirus B6 (strain Schmitt)


POLG_CXB6SGenome polyprotein

1 entry

Echovirus 1 (strain Human/Egypt/Farouk/1951) (E-1)


POLG_EC01FGenome polyprotein

1 entry

Echovirus 11 (strain Gregory)


POLG_EC11GGenome polyprotein

1 entry

Echovirus 12 (strain Travis)


POLG_EC12TGenome polyprotein

1 entry

Echovirus 30 (strain Bastianni)


POLG_EC30BGenome polyprotein

1 entry

Echovirus 5 (strain Noyce)


POLG_EC05NGenome polyprotein

1 entry

Echovirus 6 (strain Charles)


POLG_EC06CGenome polyprotein

1 entry

Echovirus 9 (strain Barty)


POLG_EC09BGenome polyprotein

1 entry

Echovirus 9 (strain Hill)


POLG_EC09HGenome polyprotein

1 entry

Encephalomyocarditis virus (strain emc-b nondiabetogenic)


POLG_EMCVBGenome polyprotein

1 entry

Encephalomyocarditis virus (strain emc-d diabetogenic)


POLG_EMCVDGenome polyprotein

1 entry

Foot-and-mouth disease virus (isolate -/Azerbaijan/A22-550/1965 serotype A) (FMDV)


POLG_FMDVZGenome polyprotein

1 entry

Foot-and-mouth disease virus (isolate -/Brazil/C3Indaial/1971 serotype C) (FMDV)


POLG_FMDVIGenome polyprotein

1 entry

Foot-and-mouth disease virus (isolate -/Germany/A5Westerwald/1951 serotype A) (FMDV)


POLG_FMDV5Genome polyprotein

1 entry

Foot-and-mouth disease virus (isolate -/Germany/C1Oberbayen/1960 serotype C) (FMDV)


POLG_FMDVTGenome polyprotein

1 entry

Foot-and-mouth disease virus (isolate -/Spain/S8c1SantaPau/1970 serotype C) (FMDV)


POLG_FMDVSGenome polyprotein

1 entry

Foot-and-mouth disease virus (isolate Bovine/Brazil/A24Cruzeiro/1955 serotype A) (FMDV)


POLG_FMDVCGenome polyprotein

1 entry

Foot-and-mouth disease virus (isolate Bovine/Germany/O1Kaufbeuren/1966 serotype O) (FMDV)


POLG_FMDVOGenome polyprotein

1 entry

Foot-and-mouth disease virus (isolate Bovine/United Kingdom/A12Valle119/1932 serotype A) (FMDV)


POLG_FMDVAGenome polyprotein

1 entry

Foot-and-mouth disease virus (strain A10-61) (Aphthovirus A) (FMDV)


POLG_FMDV1Genome polyprotein

1 entry

Human enterovirus 70 (strain J670/71) (EV 70)


POLG_HE701Genome polyprotein

1 entry

Human enterovirus 71 (strain 7423/MS/87) (Ev 71)


POLG_HE71MGenome polyprotein

1 entry

Human enterovirus 71 (strain BrCr) (Ev 71)


POLG_HE71BGenome polyprotein

1 entry

Human hepatitis A virus genotype IA (isolate GBM) (HHAV) (Human hepatitis A virus (isolate Human/Germany/GBM/1976))


POLG_HAVGBGenome polyprotein

1 entry

Human hepatitis A virus genotype IA (isolate H2) (HHAV) (Human hepatitis A virus (isolate Human/China/H2/1982))


POLG_HAVH2Genome polyprotein

1 entry

Human hepatitis A virus genotype IA (isolate LA) (HHAV) (Human hepatitis A virus (isolate Human/Northern California/LA/1974))


POLG_HAVLAGenome polyprotein

1 entry

Human hepatitis A virus genotype IB (isolate MBB) (HHAV) (Human hepatitis A virus (isolate Human/Northern Africa/MBB/1978))


POLG_HAVMBGenome polyprotein

1 entry

Human hepatitis A virus genotype IIA (isolate CF-53) (HHAV) (Human hepatitis A virus (isolate Human/France/CF-53/1979))


POLG_HAVCFGenome polyprotein

1 entry

Human hepatitis A virus genotype IIB (isolate SLF88) (HHAV) (Human hepatitis A virus (isolate Human/Sierra Leone/SLF88/1988))


POLG_HAV88Genome polyprotein

1 entry

Human hepatitis A virus genotype IIIA (isolate NOR-21) (HHAV) (Human hepatitis A virus (isolate Human/Norway/NOR-21/1998))


POLG_HAVNOGenome polyprotein

1 entry

Human hepatitis A virus genotype IIIB (isolate HAJ85-1) (HHAV) (Human hepatitis A virus (isolate Human/Japan/HAJ85-1/1985))


POLG_HAVJ8Genome polyprotein

1 entry

Human parechovirus 1 (strain Harris) (HPeV-1) (Echovirus 22)


POLG_HPE1HGenome polyprotein

1 entry

Human parechovirus 2 (strain CT86-6760) (HPeV-2) (Echovirus 23)


POLG_HPE23Genome polyprotein

1 entry

Human rhinovirus 14 (HRV-14)

1 entry

Human rhinovirus 16 (HRV-16)

1 entry

Human rhinovirus 1A (HRV-1A)


POLG_HRV1AGenome polyprotein

1 entry

Human rhinovirus 1B (HRV-1B)


POLG_HRV1BGenome polyprotein

1 entry

Human rhinovirus 2 (HRV-2)


POLG_HRV2Genome polyprotein

1 entry

Human rhinovirus 3 (HRV-3)


POLG_HRV3Genome polyprotein

1 entry

Poliovirus type 1 (strain Sabin)


POLG_POL1SGenome polyprotein

1 entry

Poliovirus type 2 (strain Lansing)


POLG_POL2LGenome polyprotein

1 entry

Poliovirus type 2 (strain W-2)


POLG_POL2WGenome polyprotein

1 entry

Poliovirus type 3 (strain 23127)


POLG_POL32Genome polyprotein

1 entry

Poliovirus type 3 (strains P3/Leon/37 and P3/Leon 12A[1]B)


POLG_POL3LGenome polyprotein

1 entry

Porcine enterovirus 9 (strain UKG/410/73)


POLG_PEV9UGenome polyprotein

1 entry

Simian hepatitis A virus genotype V (isolate AGM-27) (SHAV) (Simian hepatitis A virus (isolate Cercopithecus/Kenya/AGM-27/1985))


POLG_HAVS2Genome polyprotein

1 entry

Swine vesicular disease virus (strain H/3 '76) (SVDV)


POLG_SVDVHGenome polyprotein

1 entry

Swine vesicular disease virus (strain UKG/27/72) (SVDV)


POLG_SVDVUGenome polyprotein

1 entry

Theiler's murine encephalomyelitis virus (strain BeAn 8386) (TMEV)


POLG_TMEVBGenome polyprotein

1 entry

Theiler's murine encephalomyelitis virus (strain GDVII) (TMEV)


POLG_TMEVGGenome polyprotein