Expression of a methotrexate-resistant dihydrofolate reductase gene by transformed hematopoietic cells of mice.
DNA-mediated gene transfer was used to introduce DNA from a methotrexate-resistant mouse fibroblast cell line into mouse bone marrow cells. This cell line contained a methotrexate-resistant dihydrofolate reductase, active at 10(-4) M methotrexate, which was electrophoretically separable from the wild-type mouse enzyme. Transformed hematopoietic cells were returned to irradiated mice and selected in vivo by methotrexate administration. Some recipients of transformed marrow cells expressed the electrophoretically distinct, methotrexate-resistant dihydrofolate reductase in hematopoietic cells. These observations suggest that successful transformation of marrow stem cells to methotrexate resistance is accomplished by insertion of a dihydrofolate reductase gene coding for a mutant enzyme that is highly resistant to methotrexate.
D000818:Animals; D001853:Bone Marrow / Q000201:enzymology*; D001854:Bone Marrow Cells; D004351:Drug Resistance; D005796:Genes; D008727:Methotrexate / Q000494:pharmacology*; D051379:Mice; D008808:Mice, Inbred CBA; D009154:Mutation; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics*; D014170:Transformation, Genetic
D013762:Tetrahydrofolate Dehydrogenase; D008727:Methotrexate