Aphthovirus

The genus Aphthovirus currently includes three species of non-enveloped viruses of the family Picornaviridae. The name given the aphthoviruses of the disease, the foot- and - mouth disease virus ( FMDV ) causes as the main representative of the genus (Greek αφθαι ( aphthai ) for small vesicles of the oral mucosa ).

Morphology

The virions are aphthoviruses of about 27 to 30 nm in size in diameter and of 60 capsomers ( T = 1) is composed. It is characterized by very smooth compared to other picornaviruses surface structure and the thinness of the capsid, the thickness is only about 3 nm on average. At the Kapsidecken with five-pointed symmetry one finds pores. Consisting of a 17 to 23 amino acids, protein flexible loop (GH loop) of the capsid protein 1D, protrudes from the surface. The conserved recognition motif RGD is capable of binding to integrins on the cell surface and uptake of virions into the cell at their peak.

The virions of the FMDV are unstable below a pH of 6.8, that of the first ERAV below 5.5. Some serotypes of FMDV produce empty, RNA-free and therefore non-infectious capsids in excess.

Genome

The genome of the aphthoviruses is 7.5 to 8.7 kb in length. Translation into a single polyprotein which is cleaved by viral proteases into the individual viral proteins can begin anzwei alternative starting points within the same reading frame. This creates two different length forms of the L- protein ( Lab and Lb ), having a proteolytic activity as a cysteine ​​protease. L proteins are also able to cleave the cellular initiation factor eIF- 4G, so that the entire cellular Cap -dependent translation is inhibited. Since the aphthoviruses like all picornaviruses to possess an IRES translation initiation at the 5 ' end of the genome, the viral protein synthesis remains unaffected.

System

  • Genus aphthovirus
  • Species Equine Rhinitis A Virus ( ERAV ) ( previously equine rhinovirus 1) )
  • Species Bovine Rhinitis B Virus ( BRAV ) ( previously bovine rhinovirus 2)
  • Species foot-and - mouth disease virus ( FMDV )
Picornavirales Virus classification National Center for Biotechnology Information Foot-and-mouth disease virus Virus#Etymology Internal ribosome entry site
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