Negative-sense ssRNA viruses

Negative ssRNA Virus
Ebola Virus
Virus classification
Group:	Group V ((−)ssRNA)
Order, Family, and Genus
Order Mononegavirales Family Bornaviridae Family Filoviridae Family Mymonaviridae Family Nyamiviridae Family Paramyxoviridae Family Pneumoviridae Family Rhabdoviridae Family Sunviridae Order Bunyavirales Family Feraviridae Family Fimoviridae Family Hantaviridae Family Jonviridae Family Nairoviridae Family Peribunyaviridae Family Phasmaviridae Family Phenuiviridae Family Tospoviridae Unassigned families: Family Arenaviridae Family Ophioviridae Family Orthomyxoviridae Unassigned genera: Genus Deltavirus

A negative-sense single-stranded RNA virus (or (-)ssRNA virus) is a virus that uses negative sense, single-stranded RNA as its genetic material. Single stranded RNA viruses are classified as positive or negative depending on the sense or polarity of the RNA. The negative viral RNA is complementary to the mRNA and must be converted to a positive RNA by RNA polymerase before translation. Therefore, the purified RNA of a negative sense virus is not infectious by itself, as it needs to be converted to a positive sense RNA for replication. These viruses belong to Group V on the Baltimore classification.

In addition, negative-sense single-stranded RNA viruses have complex genomic sequences, cell cycles, and replication habits which utilize various complexes of proteins in order to arrange itself in specific conformations and carry out necessary processes for proper survival and reproduction of its genomic sequence. The complexity of negative-sense single-stranded RNA viruses carries into its ability to suppress the innate immune response of the cells it infects and the construction of a capsid which is unique to the varying classifications of negative-sense single-stranded RNA viruses.

Negative sense ssRNA viruses need RNA polymerase to form a positive sense RNA. The positive-sense RNA acts as a viral mRNA, which is translated into proteins for the production of new virion materials. With the newly formed virions, more negative sense RNA molecules are produced.

In more details, replication of the virion consists of the following steps:

The genome size of a negative RNA virus is between 10kb to 30kb. Two genome subgroups can be distinguished, nonsegmented and segmented, and are described as such:

Two orders and twenty one families are currently recognised in this group. Several of these families contain extremely similar genetic structures and are classified under the order Mononegavirales. A number of unassigned species and genera are yet to be classified.

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