''Megabirnaviridae'' is a family of

double-stranded RNA viruses Double-stranded RNA viruses (dsRNA viruses) are a polyphyletic group of viruses that have double-stranded genomes made of ribonucleic acid. The double-stranded genome is used to transcribe a positive-strand RNA by the viral RNA-dependent RNA pol ...

with one genus ''Megabirnavirus'' which infects

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

. The group name derives from member's ''bi''partite ds''RNA'' genome and ''mega'' that is greater genome size (16 kbp) than families ''

Birnaviridae ''Birnaviridae'' is a family of double-stranded RNA viruses. Salmonid fish, birds and insects serve as natural hosts. There are currently 11 species in this family, divided among seven genera. Diseases associated with this family include infec ...

'' (6 kbp) and '' Picobirnaviridae'' (4 kbp). There is only one species in this family: ''Rosellinia necatrix megabirnavirus 1''. Diseases associated with this family include: reduced host

virulence Virulence is a pathogen's or microorganism's ability to cause damage to a host. In most, especially in animal systems, virulence refers to the degree of damage caused by a microbe to its host. The pathogenicity of an organism—its ability to ca ...

Structure

Viruses in the family ''Megabirnaviridae'' are non-enveloped, with icosahedral geometries, and T=1 symmetry. The diameter is around 50 nm.

Genome

The genome is composed of two double-stranded RNA segments of 7.2–8.9 kbp each and of a total length of 16.1 kbp. The genome codes for four proteins.

Life cycle

Viral replication is

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The ...

ic. Entry into the host cell is achieved by penetration into the host cell. Replication follows the double-stranded RNA virus replication model. Double-stranded 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, the fir ...

is the method of transcription. The virus exits the host cell by cell to cell movement. Fungi serve as the natural host. Transmission routes are parental and sexual.

Taxonomy

The family ''Megabirnaviridae'' has one genus which has one species: * ''Megabirnavirus'' ** ''Rosellinia necatrix megabirnavirus 1''

References

External links

ICTV Report: ''Megabirnaviridae''

{{Taxonbar, from=Q18811491 Virus families Riboviria