title: Isolation of a taxol-resistant Chinese hamster ovary cell mutant that has an alteration in alpha-tubulin.
abstract: Taxol is a plant alkaloid that has antimitotic activity and appears to stabilize microtubules [Schiff, P. B., Fant, J. & Horwitz, S. B. (1979) Nature (London) 277, 665-667]. Taxol-resistant cells were selected from a population of UV-mutagen-treated Chinese hamster ovary cells by a single-step procedure. These mutants have normal morphologies and growth rates but are 2- to 3-fold more resistant to the toxic effects of the drug than the wild-type parent. One out of 20 mutants screened by two-dimensional electrophoresis for chemical alterations in tubulin had an "extra" spot with a more acidic isoelectric point that alpha-tubulin. This extra spot was shown to be an electrophoretic variant alpha-tubulin by its copurification with tubulin in crude microtubule-containing preparations and by one-dimensional peptide mapping. The alpha-tubulin mutant was found to be temperature sensitive for growth, and this property was used as the basis for the selection of revertants. Seventeen temperature-resistant revertants of the alpha-tubulin mutant were selected for their ability to grow at 40 degrees C and three of these revertants were found to have simultaneously lost their taxol resistance and the electrophoretic variant alpha-tubulin. These results provide evidence that an alteration in alpha-tubulin can confer taxon resistance on a mammalian cell line and suggest that alpha-tubulin is essential for cell viability.
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D007526:Isoelectric Point; D008870:Microtubules / Q000187:drug effects*; D009154:Mutation; D010053:Ovary; D017239:Paclitaxel; D010446:Peptide Fragments / Q000032:analysis; D014404:Tubulin / Q000235:genetics*
chemical_list: D000470:Alkaloids; D000972:Antineoplastic Agents, Phytogenic; D010446:Peptide Fragments; D014404:Tubulin; D017239:Paclitaxel