Semliki Forest virus
|Semliki Forest virus|
|Group:||Group IV ((+)ssRNA)|
|Species:||Semliki Forest virus|
The Semliki Forest virus was first isolated from mosquitoes in the Semliki Forest, Uganda by the Uganda Virus Research Institute in 1942 and described by Smithburn & Haddow. It is known to cause disease in both animals and man. It is an Alphavirus found in central, eastern, and southern Africa.
The Semliki Forest virus is a positive-stranded RNA virus with a genome of approximately 13,000 base pairs which encodes nine proteins. The 5’ two thirds of the genome encode four non-structural proteins concerned with RNA synthesis and the structural proteins are encoded in the 3’ third. Of the structural proteins, the C proteins makes up the icosahedral capsid which is enveloped by a lipid bilayer, derived from the host cell. The outermost surface of the virus is almost entirely covered by heterodimers of glycoproteins E1 and E2, arranged in interconnective trimers, which form an outer shell. Trimers are anchored in the membrane by an E2 cytoplasmic domain that associates with the nucleocapsid.
Replication occurs via a negative strand intermediate giving rise to a full length genomic RNA for export in new virions and a subgenomic message that is translated into the structural proteins.
Semliki Forest virus is spread mainly by mosquito bites. It is not able to infect mammals through inhalation or gastrointestinal exposure, although rodents in the laboratory can be infected by intranasal instillation. The virus is able to cause a lethal encephalitis in rodents, but generally only mild symptoms in humans. Only one lethal human infection has been reported. In this one case, the patient was immunodeficient and had been exposed to large amounts of virus in the laboratory.
Semliki Forest virus has been used extensively in biological research as a model of the viral life cycle and of viral neuropathy. Due to its broad host range and efficient replication, it has also been developed as a vector for genes encoding vaccines and anti-cancer agents, and as a tool in gene therapy.
- PMID 10882067 (PubMed)
- Smithburn KC & Haddow AJ (1944) Semliki Forest Virus I. Isolation and Pathogenic Properties. J. Immunol. 49 p141-157
- PMID 10501479 (PubMed)
- PMID 2982998 (PubMed)
- PMID 2158754 (PubMed)
- PMID 424742 (PubMed)
- PMID 20692305 (PubMed)
- Lundstrom, K. (2003). "Semliki Forest virus vectors for gene therapy". Expert Opinion on Biological Therapy 3 (5): 771–777. doi:10.1517/147125220.127.116.111. PMID 12880377.
- de Cedron, M.G., Ehsani, N., Mikkola, M.L., Garcia, J.A., and Kaariainen, L. RNA helicase activity of Semliki Forest virus replicase protein NSP2. FEBS Lett. 448: 19-22 (1999)
- Hardy P.A., Mazzini M.J., Schweitzer C., Lundstrom K., Glode L.M. Recombinant Semliki forest virus infects and kills human prostate cancer cell lines and prostatic duct epithelial cells ex vivo. Int J Mol Med. 2000 Mar;5(3):241-5.