Brome mosaic virus
Encyclopedia
Brome mosaic virus is a small (27 nm, 86S), positive-stranded, icosahedral RNA
plant virus belonging to the family Bromoviridae of the alphavirus-like superfamily.
BMV commonly infects Bromus inermis
(see Bromus
) and other grasses, can be found almost anywhere wheat is grown, and thrives in areas with heavy foot or machinery traffic. It is also one of the few grass viruses that infects dicotyledonous plants; however, it primarily infects monocotyledonous plants, such as barley and others in the family Gramineae.
BMV was first isolated in 1942 from bromegrass (Bromus inermis) (Lane, 1974), had its genomic
organization determined by the 1970s, and was completely sequenced with commercially available clone
s by the 1980s (Ahlquist et al., 1981; Lane, 2003).
The alphavirus-like superfamily includes more than 250 plant and animal viruses including Tobacco mosaic virus, Semliki forest virus, Hepatitis E virus, Sindbis virus, and arboviruses (which cause certain types of encephalitis
) (Sullivan & Ahlquist, 1997; Lampio, 1999). Many of the positive-strand RNA viruses that belong to the alphavirus family share a high degree of similarity in proteins involved in genomic replication and synthesis (Ahlquist et al., 1985; French & Ahlquist, 1988). The sequence similarities of RNA replication genes
and strategies for BMV have been shown to extend to a wide range of plant and animal viruses beyond the alphaviruses, including many other positive-strand RNA viruses from other families (Ahlquist, 1992). Understanding how these viruses replicate and targeting key points in their life cycle can help advance antiviral treatments worldwide.
BMV consists of a genome
that is divided into three 5' cap
ped RNAs. RNA1 (3.2 kb) encodes a protein called 1a (109 kDa), which contains both an N-proximal methyltransferase
domain and a C-proximal helicase
-like domain. The methyltransferase domain shows sequence similarity to other alphavirus m7G methyltransferases and guanyltransferases, called nsP1 proteins, involved in RNA capping (Ahola & Ahlquist, 1999). RNA2 (2.9 kb) encodes the 2a protein (94 kDa), the RNA-dependent RNA polymerase, responsible for replication of the viral genome (Ahlquist, 1992; Sullivan & Ahlquist, 1997). The dicistronic RNA3 (2.1 kb) encodes for two proteins, the 3a protein (involved in cell-to-cell migration during infection) and the coat protein (for RNA encapsidation and vascular spread), which is expressed from a subgenomic replication intermediate mRNA, called RNA4 (0.9 kb). 3a and coat protein are essential for systemic infection in plants but not RNA replication (Sacher & Ahlquist, 1989; Sullivan & Ahlquist, 1997; Diez et al., 2000).
RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....
plant virus belonging to the family Bromoviridae of the alphavirus-like superfamily.
BMV commonly infects Bromus inermis
Bromus inermis
Bromus inermis is a species of the true grass family . This bunchgrass is native to Europe- Common names :* Arctic brome – English [Bromus inermis subsp. pumpellianus]* Austrian bromegrass – English [Bromus inermis subsp. inermis]...
(see Bromus
Bromus
Bromus is a large genus of the grass family . Estimates in the scientific literature of the number of species have ranged from 100 to 400, but plant taxonomists currently recognize around 160–170 species...
) and other grasses, can be found almost anywhere wheat is grown, and thrives in areas with heavy foot or machinery traffic. It is also one of the few grass viruses that infects dicotyledonous plants; however, it primarily infects monocotyledonous plants, such as barley and others in the family Gramineae.
BMV was first isolated in 1942 from bromegrass (Bromus inermis) (Lane, 1974), had its genomic
Genome
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....
organization determined by the 1970s, and was completely sequenced with commercially available clone
Cloning
Cloning in biology is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments , cells , or...
s by the 1980s (Ahlquist et al., 1981; Lane, 2003).
The alphavirus-like superfamily includes more than 250 plant and animal viruses including Tobacco mosaic virus, Semliki forest virus, Hepatitis E virus, Sindbis virus, and arboviruses (which cause certain types of encephalitis
Encephalitis
Encephalitis is an acute inflammation of the brain. Encephalitis with meningitis is known as meningoencephalitis. Symptoms include headache, fever, confusion, drowsiness, and fatigue...
) (Sullivan & Ahlquist, 1997; Lampio, 1999). Many of the positive-strand RNA viruses that belong to the alphavirus family share a high degree of similarity in proteins involved in genomic replication and synthesis (Ahlquist et al., 1985; French & Ahlquist, 1988). The sequence similarities of RNA replication genes
Gênes
Gênes is the name of a département of the First French Empire in present Italy, named after the city of Genoa. It was formed in 1805, when Napoleon Bonaparte occupied the Republic of Genoa. Its capital was Genoa, and it was divided in the arrondissements of Genoa, Bobbio, Novi Ligure, Tortona and...
and strategies for BMV have been shown to extend to a wide range of plant and animal viruses beyond the alphaviruses, including many other positive-strand RNA viruses from other families (Ahlquist, 1992). Understanding how these viruses replicate and targeting key points in their life cycle can help advance antiviral treatments worldwide.
BMV consists of a genome
Genome
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....
that is divided into three 5' cap
5' cap
The 5' cap is a specially altered nucleotide on the 5' end of precursor messenger RNA and some other primary RNA transcripts as found in eukaryotes. The process of 5' capping is vital to creating mature messenger RNA, which is then able to undergo translation...
ped RNAs. RNA1 (3.2 kb) encodes a protein called 1a (109 kDa), which contains both an N-proximal methyltransferase
Methyltransferase
A methyltransferase is a type of transferase enzyme that transfers a methyl group from a donor to an acceptor.Methylation often occurs on nucleic bases in DNA or amino acids in protein structures...
domain and a C-proximal helicase
Helicase
Helicases are a class of enzymes vital to all living organisms. They are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separating two annealed nucleic acid strands using energy derived from ATP hydrolysis.-Function:Many cellular processes Helicases are a...
-like domain. The methyltransferase domain shows sequence similarity to other alphavirus m7G methyltransferases and guanyltransferases, called nsP1 proteins, involved in RNA capping (Ahola & Ahlquist, 1999). RNA2 (2.9 kb) encodes the 2a protein (94 kDa), the RNA-dependent RNA polymerase, responsible for replication of the viral genome (Ahlquist, 1992; Sullivan & Ahlquist, 1997). The dicistronic RNA3 (2.1 kb) encodes for two proteins, the 3a protein (involved in cell-to-cell migration during infection) and the coat protein (for RNA encapsidation and vascular spread), which is expressed from a subgenomic replication intermediate mRNA, called RNA4 (0.9 kb). 3a and coat protein are essential for systemic infection in plants but not RNA replication (Sacher & Ahlquist, 1989; Sullivan & Ahlquist, 1997; Diez et al., 2000).