''Emesvirus'' is a genus of

positive-strand RNA viruses Positive-strand RNA viruses (+ssRNA viruses) are a group of related viruses that have positive-sense, single-stranded genomes made of ribonucleic acid. The positive-sense genome can act as messenger RNA (mRNA) and can be directly translated int ...

, in the family ''

Fiersviridae ''Fiersviridae'' is a family of positive-strand RNA viruses which infect prokaryotes. Bacteria serve as the natural host. They are small viruses with linear, positive-sense, single-stranded RNA genomes that encode four proteins. All phages of t ...

''.

Enterobacteria Enterobacteriaceae is a large family (biology), family of Gram-negative bacteria. It includes over 30 genera and more than 100 species. Its classification above the level of Family (taxonomy), family is still a subject of debate, but one class ...

serve as natural hosts. There are three species in this genus. In 2020, the genus was renamed from ''Levivirus'' to its current name.

Structure

Viruses in ''Emesvirus'' are non-enveloped, with

icosahedral In geometry, an icosahedron ( or ) is a polyhedron with 20 faces. The name comes . The plural can be either "icosahedra" () or "icosahedrons". There are infinitely many non- similar shapes of icosahedra, some of them being more symmetrical tha ...

and Spherical geometries, and T=3 symmetry. The capsid diameter is around 26 nm.

Genome

Emesviruses have a

positive-sense In molecular biology and genetics, the sense of a nucleic acid molecule, particularly of a strand of DNA or RNA, refers to the nature of the roles of the strand and its complement in specifying a sequence of amino acids. Depending on the context, ...

, single-stranded RNA genome. The genome is linear and non-segmented and around 3.5kb in length. The genome codes for four proteins, which are the

coat A coat is typically an outer garment for the upper body, worn by any gender for warmth or fashion. Coats typically have long sleeves and are open down the front, and closing by means of buttons, zippers, hook-and-loop fasteners (AKA velcro), ...

replicase RNA-dependent RNA polymerase (RdRp) or RNA replicase is an enzyme that catalyzes the replication of RNA from an RNA template. Specifically, it catalyzes synthesis of the RNA strand complementary to a given RNA template. This is in contrast to ...

, maturation, and

lysis Lysis ( ; from Greek 'loosening') is the breaking down of the membrane of a cell, often by viral, enzymic, or osmotic (that is, "lytic" ) mechanisms that compromise its integrity. A fluid containing the contents of lysed cells is called a ...

protein.

Life cycle

Entry into the host cell is achieved by

adsorption Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the ''adsorbate'' on the surface of the ''adsorbent''. This process differs from absorption, in which a ...

into the host cell. Replication follows the positive-strand RNA virus replication model. Positive-strand RNA virus

transcription Transcription refers to the process of converting sounds (voice, music etc.) into letters or musical notes, or producing a copy of something in another medium, including: Genetics * Transcription (biology), the copying of DNA into RNA, often th ...

is the method of transcription.

Translation Translation is the communication of the semantics, meaning of a #Source and target languages, source-language text by means of an Dynamic and formal equivalence, equivalent #Source and target languages, target-language text. The English la ...

takes place by suppression of termination. The virus exits the host cell by bacteria lysis. Enterobacteria serve as the natural host.

Taxonomy

The genus ''Emesvirus'' has the following two species: * ''Emesvirus japonicum'' * ''Emesvirus piscicola'' * ''Emesvirus zinderi'', commonly called

bacteriophage MS2 Bacteriophage MS2 (''Emesvirus zinderi''), commonly called MS2, is an icosahedral, positive-sense single-stranded RNA virus that infects the bacterium ''Escherichia coli'' and other members of the Enterobacteriaceae. MS2 is a member of a family ...

References

External links

Viralzone: Levivirus

ICTV
{{Taxonbar, from=Q16999917 Virus genera Fiersviridae