Notes on Genus: Parechovirus


Type member: Human parechovirus


General Description

The genus Parechovirus (from the former name of the type member, enteric cytopathic human orphan) 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 without a polyC tract, and there is neither a leader protease nor an internal capsid (1A) protein.


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 c. 7.3 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 at the N-terminus.

Type Member Genomic Organization

The genome of about 7,300 nucleotides is translated into a single polyprotein, which is subsequently processed into ten products:
1B  31.7 kDaCoat protein VP2 (surface capsid protein)
1C 28.3 kDaCoat protein VP3 (surface capsid protein)
1D 26.4 kDaCoat protein VP1 (surface capsid protein)
2A 16.6 kDanon-structural protein, possibly a protease
2B 13.5 kDanon-structural protein
2C 37.9 kDanon-structural protein
3A 13.3 kDanon-structural protein
3B 2.2 kDaGenome-linked protein (VPg)
3C 22.5 kDaprotease
3D 53.7 kDapolymerase