title: Vectors containing a prokaryotic dihydrofolate reductase gene transform Drosophila cells to methotrexate-resistance.
abstract: Transformed Drosophila Kc cell lines, resistant to methotrexate, an inhibitor of de novo purine and pyrimidine synthesis, have been obtained by calcium phosphate transfection of plasmids containing a sequence coding for a methotrexate-resistant dihydrofolate reductase enzyme (DHFR). The introduced DNA is stably maintained in the cells as head-to-tail multimeric structures of the initial DNA sequence even after several months of culture in the presence of the selective agent. The introduced sequences are present at a high copy number in the transformed cells and express cytoplasmic RNAs transcribed from the DHFR gene.
mesh_terms: D000818:Animals; D002460:Cell Line; D004247:DNA / Q000302:isolation & purification; D004330:Drosophila / Q000235:genetics*; D004351:Drug Resistance; D005784:Gene Amplification; D005822:Genetic Vectors; D008727:Methotrexate / Q000494:pharmacology; D009690:Nucleic Acid Conformation; D010957:Plasmids; D012313:RNA / Q000302:isolation & purification; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics*; D014170:Transformation, Genetic
chemical_list: D012313:RNA; D004247:DNA; D013762:Tetrahydrofolate Dehydrogenase; D008727:Methotrexate