Notes on Genus: Tremovirus


Type member: Avian encephalomyelitis virus


General Description

The genus Tremovirus (from from an alternative name given to avian encephalomyelitis virus, “epidemic tremor”) is one of the genera in the family Picornaviridae. Genome organisation is fairly conserved within the family but members of this genus have a 5'-UTR which has no polyC tract, it has neither a leader protein nor an internal capsid (1A) protein and the 2A protein is not a protease.


Virions isometric (icosahedral), not enveloped 30 nm in diameter, made of 60 units (protomers) each consisting of one molecule of each of three surface coat proteins.


Monopartite positive sense single-stranded RNA 7.0-7.1 kb in length. There is a genome-linked protein (VPg) at the 5'-terminus and a 3'-polyA tail.

Genus Genomic Organization

The RNA encodes a single polyprotein that is subsequently processed into the functional products. The major structural proteins are encoded near the N-terminus.

Type Member Genomic Organization

The genome of about 7,050 nucleotides is translated into a single polyprotein, which is subsequently processed into ten products:
1B  26.8 kDaCoat protein VP2 (surface capsid protein)
1C 27.0 kDaCoat protein VP3 (surface capsid protein)
1D 31.8 kDaCoat protein VP1 (surface capsid protein)
2A 18.0 kDanon-structural protein
2B 10.2 kDanon-structural protein
2C 25.1 kDanon-structural protein
3A 18.6 kDanon-structural protein
3B 2.3 kDaGenome-linked protein (VPg)
3C 23.9 kDaprotease
3D 55.6 kDapolymerase