title: Improved Semliki Forest virus vectors for receptor research and gene therapy.
abstract: We have modified Semliki Forest virus (SFV) vectors to broaden their application range. Here we describe a series of site-directed mutagenesis experiments on the SFV subgenomic 26S promoter to down-regulate the heterologous gene expression. Several mutants showed a dramatic effect on transgene expression levels in BHK cells. The luciferase activity was reduced to approximately 30%, 3%, and 1% compared to the wild type promoter. Similarly, a decrease in beta-galactosidase activity was observed in BHK cells and after injection into the striatum of male Wistar rats. Novel non-cytopathogenic and temperature-sensitive SFV vectors have recently been developed by introduction of point mutations in the viral nonstructural genes nsP2 and nsP4. These vectors do not show the typical shut down of host cell protein synthesis after SFV infections and therefore allow for a substantially prolonged survival of host cells. Both the mutant vectors demonstrating lower and more physiological expression levels and the non-cytopathogenic vectors should be valuable tools for various applications within receptor research. Furthermore, recent studies suggest that SFV vectors can be efficient gene delivery vehicles for gene therapy applications.
authors.affiliation: F. Hoffmann-La Roche, Research Laboratories, 4070 Basel, Switzerland.
authors.forename: K
authors.initials: K
authors.lastname: Lundstrom
authors.forename: P
authors.initials: P
authors.lastname: Ziltener
authors.forename: D
authors.initials: D
authors.lastname: Hermann
authors.forename: C
authors.initials: C
authors.lastname: Schweitzer
authors.forename: J G
authors.initials: JG
authors.lastname: Richards
authors.forename: F
authors.initials: F
authors.lastname: Jenck
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism / Q000821:virology; D002460:Cell Line; D006224:Cricetinae; D003588:Cytopathogenic Effect, Viral / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D015870:Gene Expression; D017930:Genes, Reporter; D015316:Genetic Therapy; D005822:Genetic Vectors; D007763:Lac Operon; D008156:Luciferases / Q000235:genetics; D008297:Male; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic; D051381:Rats; D017208:Rats, Wistar; D011991:Receptors, Virus; D012107:Research Design; D012672:Semliki forest virus / Q000235:genetics* / Q000472:pathogenicity; D013696:Temperature; D017361:Viral Nonstructural Proteins / Q000235:genetics
chemical_list: D004279:DNA, Viral; D011991:Receptors, Virus; D017361:Viral Nonstructural Proteins; D008156:Luciferases