Picornaviridae (taxid:12058)
VIRION

Non-enveloped, spherical, about 30 nm in diameter, pseudo T=3 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 (IRES). 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). Enzymes:RNA dependent RNA polymerase, VPG Nucleotidylylase, terminal adenylyltransferase, proteases.
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.
ENZYMES
- RNA-dependent RNA polymerase [RdRp]
- VPG-type capping [VPg]
- NTPase-helicase [2C]
- Polyprotein major protease (Peptidase C3) [3Cpro, 2A]
- Self cleaving protease (Peptidase C28) [L]
REPLICATION
CYTOPLASMIC
- Attachement of the virus to host receptors mediates endocytosis of the virus into the host cell.
- 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.
- VPg is removed from the viral RNA, which is then translated into a processed polyprotein.
- In entero-, rhino-, and aphthoviruses, shutoff of cellular cap-dependent translation through the cleavage of translation initiation factors by viral protease.
- Replication occurs in viral factories made of membrane vesicles derived from the ER. A dsRNA genome is synthesized from the genomic ssRNA(+).
- The dsRNA genome is transcribed/replicated thereby providing viral mRNAs/new ssRNA(+) genomes.
- New genomic RNA is believed to be packaged into preassembled procapsids.
- Cell lysis and virus release.
- 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
(all links/actions below point to uniprot.org website)95 entries grouped by strain
2 entries
Encephalomyocarditis virus (strain Rueckert) (EMCV) reference strain
2 entries
Poliovirus type 1 (strain Mahoney) reference strain
1 entry
Aichi virus (strain Human/A846/88/1989) (AiV) (Aichi virus (strain A846/88)) reference strain
1 entry
Avian encephalomyelitis virus (strain Calnek vaccine) (AEV) reference strain
1 entry
Cosavirus A (isolate Human/Pakistan/0553/-) (HCoSV-A) reference strain
1 entry
Foot-and-mouth disease virus serotype O (FMDV) reference strain
1 entry
Human hepatitis A virus genotype IB (isolate HM175) (HHAV) (Human hepatitis A virus (isolate Human/Australia/HM175/1976)) reference strain
1 entry
Human parechovirus 2 (strain Williamson) (HPeV-2) (Echovirus 23) reference strain
1 entry
Human rhinovirus A serotype 89 (strain 41467-Gallo) (HRV-89) reference strain
1 entry
Salivirus A (isolate Human/Nigeria/NG-J1/2007) (SV-A) reference strain
1 entry
Seneca Valley virus (isolate -/United States/SSV-001/2002) (SVV) reference strain
2 entries
Coxsackievirus B3 (strain Nancy)
2 entries
Encephalomyocarditis virus
2 entries
Human enterovirus 71 (strain USA/BrCr/1970) (EV71) (EV-71)
2 entries
Mengo encephalomyocarditis virus
2 entries
Theiler's murine encephalomyelitis virus (strain DA) (TMEV)
2 entries
Theiler's murine encephalomyelitis virus (strain GDVII) (TMEV)
1 entry
Avian encephalomyelitis virus (strain L2Z) (AEV)
1 entry
Avian encephalomyelitis virus (strain Van Reokel) (AEV)
1 entry
Bovine enterovirus (strain VG-5-27) (BEV)
1 entry
Coxsackievirus A16 (strain G-10)
1 entry
Coxsackievirus A16 (strain Tainan/5079/98)
1 entry
Coxsackievirus A21 (strain Coe)
1 entry
Coxsackievirus A24 (strain EH24/70)
1 entry
Coxsackievirus A9 (strain Griggs)
1 entry
Coxsackievirus B1 (strain Japan)
1 entry
Coxsackievirus B2 (strain Ohio-1)
1 entry
Coxsackievirus B3 (strain Woodruff)
1 entry
Coxsackievirus B4 (strain E2)
1 entry
Coxsackievirus B4 (strain JVB / Benschoten / New York/51)
1 entry
Coxsackievirus B5 (strain Peterborough / 1954/UK/85)
1 entry
Coxsackievirus B6 (strain Schmitt)
1 entry
Echovirus 1 (strain Human/Egypt/Farouk/1951) (E-1)
1 entry
Echovirus 11 (strain Gregory)
1 entry
Echovirus 12 (strain Travis)
1 entry
Echovirus 30 (strain Bastianni)
1 entry
Echovirus 5 (strain Noyce)
1 entry
Echovirus 6 (strain Charles)
1 entry
Echovirus 9 (strain Barty)
1 entry
Echovirus 9 (strain Hill)
1 entry
Encephalomyocarditis virus (strain emc-b nondiabetogenic)
1 entry
Encephalomyocarditis virus (strain emc-d diabetogenic)
1 entry
Foot-and-mouth disease virus (isolate -/Azerbaijan/A22-550/1965 serotype A) (FMDV)
1 entry
Foot-and-mouth disease virus (isolate -/Brazil/C3Indaial/1971 serotype C) (FMDV)
1 entry
Foot-and-mouth disease virus (isolate -/Germany/A5Westerwald/1951 serotype A) (FMDV)
1 entry
Foot-and-mouth disease virus (isolate -/Germany/C1Oberbayen/1960 serotype C) (FMDV)
1 entry
Foot-and-mouth disease virus (isolate -/Spain/S8c1SantaPau/1970 serotype C) (FMDV)
1 entry
Foot-and-mouth disease virus (isolate Bovine/Brazil/A24Cruzeiro/1955 serotype A) (FMDV)
1 entry
Foot-and-mouth disease virus (isolate Bovine/United Kingdom/A12Valle119/1932 serotype A) (FMDV)
1 entry
Foot-and-mouth disease virus (isolate Swine/Taiwan/OTai/1997 serotype O) (FMDV)
1 entry
Foot-and-mouth disease virus (strain A10/Holland/1961 serotype A) (FMDV)
1 entry
Foot-and-mouth disease virus serotype Asia-1 (FMDV)
1 entry
Foot-and-mouth disease virus serotype SAT-2 (FMDV)
1 entry
Human enterovirus 70 (strain J670/71) (EV70) (EV-70)
1 entry
Human enterovirus 71 (EV71) (EV-71)
1 entry
Human enterovirus 71 (strain 7423/MS/87) (EV71) (EV-71)
1 entry
Human enterovirus D68 (EV68) (EV-68)
1 entry
Human hepatitis A virus genotype IA (isolate GBM) (HHAV) (Human hepatitis A virus (isolate Human/Germany/GBM/1976))
1 entry
Human hepatitis A virus genotype IA (isolate H2) (HHAV) (Human hepatitis A virus (isolate Human/China/H2/1982))
1 entry
Human hepatitis A virus genotype IA (isolate LA) (HHAV) (Human hepatitis A virus (isolate Human/Northern California/LA/1974))
1 entry
Human hepatitis A virus genotype IB (isolate MBB) (HHAV) (Human hepatitis A virus (isolate Human/Northern Africa/MBB/1978))
1 entry
Human hepatitis A virus genotype IIA (isolate CF-53) (HHAV) (Human hepatitis A virus (isolate Human/France/CF-53/1979))
1 entry
Human hepatitis A virus genotype IIB (isolate SLF88) (HHAV) (Human hepatitis A virus (isolate Human/Sierra Leone/SLF88/1988))
1 entry
Human hepatitis A virus genotype IIIA (isolate NOR-21) (HHAV) (Human hepatitis A virus (isolate Human/Norway/NOR-21/1998))
1 entry
Human hepatitis A virus genotype IIIB (isolate HAJ85-1) (HHAV) (Human hepatitis A virus (isolate Human/Japan/HAJ85-1/1985))
1 entry
Human klassevirus 1 (HKV-1)
1 entry
Human parechovirus 1 (strain Harris) (HPeV-1) (Echovirus 22)
1 entry
Human parechovirus 5 (strain CT86-6760) (HPeV-5) (Echovirus 23)
1 entry
Human rhinovirus 14 (HRV-14)
1 entry
Human rhinovirus 16 (HRV-16)
1 entry
Human rhinovirus 1A (HRV-1A)
1 entry
Human rhinovirus 1B (HRV-1B)
1 entry
Human rhinovirus 2 (HRV-2)
1 entry
Human rhinovirus 3 (HRV-3)
1 entry
Human rhinovirus C (strain C15) (HRV-C15)
1 entry
Ljunganvirus 1 (LV) (Ljungan virus 1)
1 entry
Poliovirus type 1 (strain Sabin)
1 entry
Poliovirus type 2 (strain Lansing)
1 entry
Poliovirus type 2 (strain W-2)
1 entry
Poliovirus type 3 (strain 23127)
1 entry
Poliovirus type 3 (strains P3/Leon/37 and P3/Leon 12A[1]B)
1 entry
Porcine enterovirus 9 (strain UKG/410/73)
1 entry
Saffold virus (SafV) (Human TMEV-like virus-Saffold)
1 entry
Simian hepatitis A virus genotype V (isolate AGM-27) (SHAV) (Simian hepatitis A virus (isolate Cercopithecus/Kenya/AGM-27/1985))
1 entry
Swine vesicular disease virus (strain H/3 '76) (SVDV)
1 entry
Swine vesicular disease virus (strain UKG/27/72) (SVDV)
1 entry
Theiler's murine encephalomyelitis virus (strain BeAn 8386) (TMEV)
hepatovirus B1 taxid:1708572
Protein | ModelArchive |
Genome polyprotein | ma-jd-viral-30863 |