title: Temperature-sensitive nonsense mutations in essential genes of Escherichia coli.
abstract: Cells containing nonsense mutations in essential genes have been isolated in a strain of Escherichia coli that carried the su4(ts) gene which specifies a temperature-sensitive tyrosine transfer ribonucleic acid. Such cells are unable to form colonies at temperatures which inactivate this suppressor transfer ribonucleic acid. A screening procedure for the identification of mutants that carry temperature-sensitive nonsense mutations in essential genes is described, and certain properties of two such mutants are reported.
mesh_terms: D002874:Chromosome Mapping; D004926:Escherichia coli / Q000201:enzymology / Q000302:isolation & purification / Q000378:metabolism*; D009154:Mutation; D009604:Nitrosoguanidines; D010452:Peptide Biosynthesis; D010641:Phenotype; D012329:RNA, Bacterial / Q000096:biosynthesis*; D012343:RNA, Transfer / Q000096:biosynthesis*; D013194:Staining and Labeling; D013489:Suppression, Genetic; D013696:Temperature; D014161:Transduction, Genetic
chemical_list: D009604:Nitrosoguanidines; D012329:RNA, Bacterial; D012343:RNA, Transfer