title: Generation of helper-free amphotropic retroviruses that transduce a dominant-acting, methotrexate-resistant dihydrofolate reductase gene.
abstract: We constructed several retroviruses which transduced a mutant dihydrofolate reductase gene that was resistant to methotrexate inhibition and functioned as a dominant selectable marker. The titer of dihydrofolate reductase-transducing virus produced by virus-producing cells could be increased to very high levels by selection of the cells in increasing concentrations of methotrexate. Helper virus-free dihydrofolate reductase-transducing virus was also generated by using a broad-host-range amphotropic retroviral packaging system. Cell lines producing helper-free dihydrofolate reductase-transducing virus with a titer of 4 X 10(6) per ml were generated. These retroviral vectors should have general utility for high-efficiency transduction of genes in cultured cells and in animals.
authors.forename: A D
authors.initials: AD
authors.lastname: Miller
authors.forename: M F
authors.initials: MF
authors.lastname: Law
authors.forename: I M
authors.initials: IM
authors.lastname: Verma
mesh_terms: D000818:Animals; D002415:Cats; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004351:Drug Resistance; D005347:Fibroblasts / Q000201:enzymology; D005784:Gene Amplification; D005822:Genetic Vectors; D009052:Leukemia Virus, Murine / Q000235:genetics*; D008727:Methotrexate / Q000494:pharmacology; D051379:Mice; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics*; D014161:Transduction, Genetic
chemical_list: D013762:Tetrahydrofolate Dehydrogenase; D008727:Methotrexate