Nanoviridae
Encyclopedia
The Nanoviridae are a family of virus
es, including the following genera:
composed of a single strand of DNA
which is arranged in a circular fashion. They have a multipartite genome, with between 6 and 11 circular ssDNAs, each of ~1kb. Their name is derived from the Greek word “nano” meaning dwarf, because of their small genome and also the stunting effect on infected plants.
Virions of this family have a simple composition: they have a capsid
but no surrounding envelope. The capsid is round in shape, has a diameter of between 18-20 nm and displays icosahedral symmetry.
of a host cell, the small DNA molecules that have become encapsidated with the genomic ssDNA act as primers
. They bind to complementary regions and help in initiation of DNA synthesis by host polymerases. On completion of synthesis, there will be a double stranded intermediate that is transcribed
unidirectionally. Most individual nanovirus particles only encode for a single protein
.
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
es, including the following genera:
- Genus Nanovirus; type species: Subterranean clover stunt virus
- Genus Babuvirus; type species: Banana bunchy top virusBanana bunchy top virusBanana bunchy top virus is a plant pathogenic virus of the family Nanoviridae.-Information:In 2004 Hawaii rediscovered Banana Bunchy top virus in residential areas close to major commercial plantations. It was first discovered in Hawaii in 1989...
Virus structure and genome
Nanoviruses have a genomeGenome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
composed of a single strand of DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
which is arranged in a circular fashion. They have a multipartite genome, with between 6 and 11 circular ssDNAs, each of ~1kb. Their name is derived from the Greek word “nano” meaning dwarf, because of their small genome and also the stunting effect on infected plants.
Virions of this family have a simple composition: they have a capsid
Capsid
A capsid is the protein shell of a virus. It consists of several oligomeric structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The capsid encloses the genetic...
but no surrounding envelope. The capsid is round in shape, has a diameter of between 18-20 nm and displays icosahedral symmetry.
Replication
After infectionInfection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
of a host cell, the small DNA molecules that have become encapsidated with the genomic ssDNA act as primers
Primer (molecular biology)
A primer is a strand of nucleic acid that serves as a starting point for DNA synthesis. They are required for DNA replication because the enzymes that catalyze this process, DNA polymerases, can only add new nucleotides to an existing strand of DNA...
. They bind to complementary regions and help in initiation of DNA synthesis by host polymerases. On completion of synthesis, there will be a double stranded intermediate that is transcribed
Transcription (genetics)
Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...
unidirectionally. Most individual nanovirus particles only encode for a single protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
.