title: Amplification of the gene for histidyl-tRNA synthetase in histidinol-resistant Chinese hamster ovary cells.
abstract: Histidinol-resistant (HisOHR) mutants with up to a 30-fold increase in histidyl-tRNA synthetase activity have been isolated by stepwise adaptation of wild-type Chinese hamster ovary (CHO) cells to increasing amounts of histidinol in the medium. Immunoprecipitation of [35S]methionine-labeled cell lysates with antibodies to histidyl-tRNA synthetase showed increased synthesis of the enzyme in histidinol-resistant cells. The histidinol-resistant cell lines had an increase in translatable polyadenylated mRNA for histidyl-tRNA synthetase. A cDNA for CHO histidyl-tRNA synthetase has been cloned, using these histidyl-tRNA synthetase-overproducing mutants as the source of mRNA. Southern blot analysis of wild-type and histidinol-resistant cells with this cDNA showed that the histidyl-tRNA synthetase DNA bands were amplified in the resistant cells. These HisOHR cells owed their resistance to histidinol to amplification of the gene for histidyl-tRNA synthetase.
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000235:genetics*; D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA; D004351:Drug Resistance; D005260:Female; D005347:Fibroblasts / Q000187:drug effects; D005784:Gene Amplification; D006643:Histidine-tRNA Ligase / Q000235:genetics*; D006641:Histidinol / Q000494:pharmacology; D008970:Molecular Weight; D011061:Poly A / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis
chemical_list: D012333:RNA, Messenger; D011061:Poly A; D006641:Histidinol; D004247:DNA; D000604:Amino Acyl-tRNA Synthetases; D006643:Histidine-tRNA Ligase