''Umatilla virus'' (UMAV) is a dsRNA virus in the family '' Reoviridae'', subfamily ''

Sedoreovirinae ''Sedoreovirinae'' (''sedo'' = smooth) is a subfamily of the ''Reoviridae'' family of viruses. Viruses in this subfamily are distinguished by the absence of a turreted protein on the inner capsid to produce a smooth surface. Characteristics Like ...

'', and the genus ''

Orbivirus ''Orbivirus'' is a genus of double-stranded RNA viruses in the family ''Reoviridae'' and subfamily ''Sedoreovirinae''. Unlike other reoviruses, orbiviruses are arboviruses. They can infect and replicate within a wide range of arthropod and verte ...

''. This arbovirus was first isolated in 1969 in Umatilla County, Oregon in a group of ''Culex pipiens'' mosquitoes. The viral host is the '' Passer domesticus'' bird with the vectors being '' Culex'' mosquitoes.

Virus structure

According to the Baltimore classification, '' Reoviridae'' are in Group III due to their

dsRNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...

genome. This family of viruses have a linear and segmented genomic arrangement and they lack a lipid envelope. Opposed to having a lipid envelope, these viruses pack their genome into a multi-layered capsid; the outer capsid being T=13 and the inner T=2. The family is divided into two subfamilies and UMAV belongs to ''Sedoreovirinae''. This subfamily lacks turrets and therefore has a smooth surface. UMAV is in the genus ''

'', which was originally named after its ring shape. The Umatilla virus genome is broken into ten segments with one packaged per virion. The ten segmented genome encodes for 7 major structural proteins and 3 major non-structural. The UMAV genome is 19,402 bp long, with 5.695% of the genome being non-coding. With UMAV being in the family ''Reoviridae'', it is a non-enveloped virus, but the core is around 30 nm in diameter. The ten segments of this linear dsRNA in the virus mostly code for a single viral protein.

Replication

Along with other viruses in the ''Reoviridae'' family, Umatilla virus replication occurs in the cytoplasm. This virus comes with some of its own replication proteins. Entrance into the host cell occurs through cell receptors endocytosis. This process is due to the interaction with sialic acid on the host. The outer capsid is removed as the virus is entering the host via endocytosis. So that the dsRNA never comes in direct contact with the cytoplasm, early replication occurs in the viral core. Both replication and assembly occur in the cytoplasm of the host cell. Host ribosomes are used to translate the viral RNA into mRNA. Virions self-assemble in they host cell cytoplasm and then exit by budding following host cell death.

Transmission

This virus is transmitted by ''Culex'' mosquitoes and is found in ''Passer domesticus'' birds.

References

{{Taxonbar, from=Q18976064 Orbiviruses