| Group IV ((+)ssRNA)|
Winter vomiting bug
| Caliciviridae, Feline calicivirus, Sapovirus, Vesivirus, Lagovirus|Murine norovirus Wikipedia
Murine norovirus (MNV) is a species of norovirus affecting mice. It was first identified in 2003. Until the 2014 discovery that human norovirus could be cultured in B cells, MNV was the only norovirus it was possible to grow in the laboratory using cell culture techniques.
Like all noroviruses, MNV has a linear, non-segmented, positive-sense RNA genome of approximately 7.5 kbp, encoding a large polyprotein which is cleaved into six smaller non-structural proteins (NS1/2 to NS7) by the viral 3C-like protease (NS6), a major structural protein (VP1) of about 58~60 kDa and a minor capsid protein (VP2). In addition to these proteins, MNV is unique amongst the noroviruses in possessing an additional fourth open reading frame overlapping the VP1 coding sequence. This additional reading frame encodes a virulence factor (VF1) which regulates the innate immune response. The 3'UTR of the viral genome forms stem-loop structures which have a role in virulence.